Re: [PATCH v2 1/2] powerpc/drmem: accelerate memory_add_physaddr_to_nid() with LMB xarray

[Anton Blanchard]

Hi Scott,

I'm hitting this issue and Rick just pointed my at your patch. Any
chance we could get it upstream?

Thanks,
Anton

> On PowerPC, memory_add_physaddr_to_nid() uses a linear search to find
> an LMB matching the given address.  This scales very poorly when there
> are many LMBs.  The poor scaling cripples drmem_init() during boot:
> lmb_set_nid(), which calls memory_add_physaddr_to_nid(), is called for
> each LMB.
> 
> If we index each LMB in an xarray by its base address we can achieve
> O(log n) search during memory_add_physaddr_to_nid(), which scales much
> better.
> 
> For example, in the lab we have a 64TB P9 machine with 256MB LMBs.
> So, suring drmem_init() we instantiate 249854 LMBs.  On a vanilla
> kernel it completes drmem_init() in ~35 seconds with a soft lockup
> trace.  On the patched kernel it completes drmem_init() in ~0.5
> seconds.
> 
> Before:
> [   53.721639] drmem: initializing drmem v2
> [   80.604346] watchdog: BUG: soft lockup - CPU#65 stuck for 23s!
> [swapper/0:1] [   80.604377] Modules linked in:
> [   80.604389] CPU: 65 PID: 1 Comm: swapper/0 Not tainted 5.6.0-rc2+
> #4 [   80.604397] NIP:  c00a4980 LR: c00a4940 CTR:
>  [   80.604407] REGS: c0002dbff8493830 TRAP: 0901
> Not tainted  (5.6.0-rc2+) [   80.604412] MSR:  82009033
>   CR: 44000248  XER: 000d [
> 80.604431] CFAR: c00a4a38 IRQMASK: 0 [   80.604431] GPR00:
> c00a4940 c0002dbff8493ac0 c1904400 c0003cfede30 [
>   80.604431] GPR04:  c0f4095a
> 002f 1000 [   80.604431] GPR08:
> cbf7ecdb7fb8 cbf7ecc2d3c8 0008 c00c0002fdfb2001 [
>   80.604431] GPR12:  c0001e8ec200 [   80.604477]
> NIP [c00a4980] hot_add_scn_to_nid+0xa0/0x3e0 [   80.604486]
> LR [c00a4940] hot_add_scn_to_nid+0x60/0x3e0 [   80.604492]
> Call Trace: [   80.604498] [c0002dbff8493ac0] [c00a4940]
> hot_add_scn_to_nid+0x60/0x3e0 (unreliable) [   80.604509]
> [c0002dbff8493b20] [c0087c10]
> memory_add_physaddr_to_nid+0x20/0x60 [   80.604521]
> [c0002dbff8493b40] [c10d4880] drmem_init+0x25c/0x2f0 [
> 80.604530] [c0002dbff8493c10] [c0010154]
> do_one_initcall+0x64/0x2c0 [   80.604540] [c0002dbff8493ce0]
> [c10c4aa0] kernel_init_freeable+0x2d8/0x3a0 [   80.604550]
> [c0002dbff8493db0] [c0010824] kernel_init+0x2c/0x148 [
> 80.604560] [c0002dbff8493e20] [c000b648]
> ret_from_kernel_thread+0x5c/0x74 [   80.604567] Instruction dump: [
> 80.604574] 392918e8 e949 e90a000a e92a 80ea000c 1d080018
> 3908ffe8 7d094214 [   80.604586] 7fa94040 419d00dc e9490010 714a0088
> <2faa0008> 409e00ac e949 7fbe5040 [   89.047390] drmem: 249854
> LMB(s)
> 
> After:
> [   53.424702] drmem: initializing drmem v2
> [   53.898813] drmem: 249854 LMB(s)
> 
> lmb_set_nid() is called from dlpar_lmb_add() so this patch will also
> improve memory hot-add speeds on big machines.
> 
> Signed-off-by: Scott Cheloha 
> ---
>  arch/powerpc/include/asm/drmem.h |  1 +
>  arch/powerpc/mm/drmem.c  | 24 
>  arch/powerpc/mm/numa.c   | 29 ++---
>  3 files changed, 35 insertions(+), 19 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/drmem.h
> b/arch/powerpc/include/asm/drmem.h index 3d76e1c388c2..90a5a9ad872b
> 100644 --- a/arch/powerpc/include/asm/drmem.h
> +++ b/arch/powerpc/include/asm/drmem.h
> @@ -88,6 +88,7 @@ static inline bool drmem_lmb_reserved(struct
> drmem_lmb *lmb) return lmb->flags & DRMEM_LMB_RESERVED;
>  }
>  
> +struct drmem_lmb *drmem_find_lmb_by_base_addr(u64 base_addr);
>  u64 drmem_lmb_memory_max(void);
>  void __init walk_drmem_lmbs(struct device_node *dn,
>   void (*func)(struct drmem_lmb *, const
> __be32 **)); diff --git a/arch/powerpc/mm/drmem.c
> b/arch/powerpc/mm/drmem.c index 44bfbdae920c..62cbe79e3860 100644
> --- a/arch/powerpc/mm/drmem.c
> +++ b/arch/powerpc/mm/drmem.c
> @@ -11,12 +11,31 @@
>  #include 
>  #include 
>  #include 
> +#include 
>  #include 
>  #include 
>  
> +static DEFINE_XARRAY(drmem_lmb_xa_base_addr);
>  static struct drmem_lmb_info __drmem_info;
>  struct drmem_lmb_info *drmem_info = &__drmem_info;
>  
> +static int drmem_cache_lmb_for_lookup(struct drmem_lmb *lmb)
> +{
> + void *ret;
> +
> + ret = xa_store(&drmem_lmb_xa_base_addr, lmb->base_addr, lmb,
> +GFP_KERNEL);
> + if (xa_is_err(ret))
> + return xa_err(ret);
> +
> + return 0;
> +}
> +
> +struct drmem_lmb *drmem_find_lmb_by_base_addr(u64 base_addr)
> +{
> + return xa_load(&drmem_lmb_xa_base_addr, base_addr);
> +}
> +
>  u64 drmem_lmb_memory_max(void)
>  {
>   struct drmem_lmb *last_lmb;
> @@ -364,6 +383,8 @@ static void __init init_drmem_v1_lmbs(const
> __be32 *prop) 
>   for_each_drmem_lmb(lmb) {
>   read_drconf_v1_cell(lmb, &prop);
> + if (drmem_cache_lmb_for_lookup(lmb) != 0)
> + 

Re: [PATCH] ring-buffer: speed up buffer resets by avoiding synchronize_rcu for each CPU

[Anton Blanchard]

Hi Nick,

> On a 144 thread system, `perf ftrace` takes about 20 seconds to start
> up, due to calling synchronize_rcu() for each CPU.
> 
>   cat /proc/108560/stack
> 0xc0003e7eb336f470
> __switch_to+0x2e0/0x480
> __wait_rcu_gp+0x20c/0x220
> synchronize_rcu+0x9c/0xc0
> ring_buffer_reset_cpu+0x88/0x2e0
> tracing_reset_online_cpus+0x84/0xe0
> tracing_open+0x1d4/0x1f0
> 
> On a system with 10x more threads, it starts to become an annoyance.
> 
> Batch these up so we disable all the per-cpu buffers first, then
> synchronize_rcu() once, then reset each of the buffers. This brings
> the time down to about 0.5s.

It's gone from somewhere more than 10 minutes (I gave up waiting) to
3 seconds. Nice work!

Tested-by: Anton Blanchard 

Thanks,
Anton

> Cc: Paul McKenney 
> Cc: Anton Blanchard 
> Cc: Steven Rostedt 
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Nicholas Piggin 
> ---
>  include/linux/ring_buffer.h |  1 +
>  kernel/trace/ring_buffer.c  | 85
> +++-- kernel/trace/trace.c|
> 4 +- 3 files changed, 73 insertions(+), 17 deletions(-)
> 
> diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
> index c76b2f3b3ac4..136ea0997e6d 100644
> --- a/include/linux/ring_buffer.h
> +++ b/include/linux/ring_buffer.h
> @@ -143,6 +143,7 @@ bool ring_buffer_iter_dropped(struct
> ring_buffer_iter *iter); unsigned long ring_buffer_size(struct
> trace_buffer *buffer, int cpu); 
>  void ring_buffer_reset_cpu(struct trace_buffer *buffer, int cpu);
> +void ring_buffer_reset_online_cpus(struct trace_buffer *buffer);
>  void ring_buffer_reset(struct trace_buffer *buffer);
>  
>  #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
> diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
> index b8e1ca48be50..3f1fd02bd14a 100644
> --- a/kernel/trace/ring_buffer.c
> +++ b/kernel/trace/ring_buffer.c
> @@ -270,6 +270,9 @@ EXPORT_SYMBOL_GPL(ring_buffer_event_data);
>  #define for_each_buffer_cpu(buffer, cpu) \
>   for_each_cpu(cpu, buffer->cpumask)
>  
> +#define for_each_online_buffer_cpu(buffer, cpu)  \
> + for_each_cpu_and(cpu, buffer->cpumask, cpu_online_mask)
> +
>  #define TS_SHIFT 27
>  #define TS_MASK  ((1ULL << TS_SHIFT) - 1)
>  #define TS_DELTA_TEST(~TS_MASK)
> @@ -4484,6 +4487,26 @@ rb_reset_cpu(struct ring_buffer_per_cpu
> *cpu_buffer) rb_head_page_activate(cpu_buffer);
>  }
>  
> +/* Must have disabled the cpu buffer then done a synchronize_rcu */
> +static void reset_disabled_cpu_buffer(struct ring_buffer_per_cpu
> *cpu_buffer) +{
> + unsigned long flags;
> +
> + raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
> +
> + if (RB_WARN_ON(cpu_buffer,
> local_read(&cpu_buffer->committing)))
> + goto out;
> +
> + arch_spin_lock(&cpu_buffer->lock);
> +
> + rb_reset_cpu(cpu_buffer);
> +
> + arch_spin_unlock(&cpu_buffer->lock);
> +
> + out:
> + raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
> +}
> +
>  /**
>   * ring_buffer_reset_cpu - reset a ring buffer per CPU buffer
>   * @buffer: The ring buffer to reset a per cpu buffer of
> @@ -4492,7 +4515,6 @@ rb_reset_cpu(struct ring_buffer_per_cpu
> *cpu_buffer) void ring_buffer_reset_cpu(struct trace_buffer *buffer,
> int cpu) {
>   struct ring_buffer_per_cpu *cpu_buffer =
> buffer->buffers[cpu];
> - unsigned long flags;
>  
>   if (!cpumask_test_cpu(cpu, buffer->cpumask))
>   return;
> @@ -4503,24 +4525,42 @@ void ring_buffer_reset_cpu(struct
> trace_buffer *buffer, int cpu) /* Make sure all commits have finished
> */ synchronize_rcu();
>  
> - raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
> + reset_disabled_cpu_buffer(cpu_buffer);
>  
> - if (RB_WARN_ON(cpu_buffer,
> local_read(&cpu_buffer->committing)))
> - goto out;
> + atomic_dec(&cpu_buffer->record_disabled);
> + atomic_dec(&cpu_buffer->resize_disabled);
> +}
> +EXPORT_SYMBOL_GPL(ring_buffer_reset_cpu);
>  
> - arch_spin_lock(&cpu_buffer->lock);
> +/**
> + * ring_buffer_reset_cpu - reset a ring buffer per CPU buffer
> + * @buffer: The ring buffer to reset a per cpu buffer of
> + * @cpu: The CPU buffer to be reset
> + */
> +void ring_buffer_reset_online_cpus(struct trace_buffer *buffer)
> +{
> + struct ring_buffer_per_cpu *cpu_buffer;
> + int cpu;
>  
> - rb_reset_cpu(cpu_buffer);
> + for_each_online_buffer_cpu(buffer, cpu) {
> + cpu_buffer = buffer->buffers[cpu];
>  
> - arch_

CFS bandwidth control hits hard lockup warnings

[Anton Blanchard]

Hi,

We are seeing hard lockup warnings caused by CFS bandwidth control code. The
test case below fails almost immediately on a reasonably large (144 thread)
POWER9 guest with:

watchdog: CPU 80 Hard LOCKUP
watchdog: CPU 80 TB:1134131922788, last heartbeat TB:1133207948315 (1804ms ago)
Modules linked in:
CPU: 80 PID: 0 Comm: swapper/80 Tainted: G L
4.20.0-rc4-00156-g94f371cb7394-dirty #98
NIP:  c018f618 LR: c0185174 CTR: c018f5f0
REGS: cfbbbd70 TRAP: 0100   Tainted: G L 
(4.20.0-rc4-00156-g94f371cb7394-dirty)
MSR:  80009033   CR: 28000222  XER: 
CFAR: c0002440 IRQMASK: 1
GPR00: c0185174 c03fef927610 c10bd500 c03fab1dbb80
GPR04: c03ffe2d3000 c018f5f0 c03ffe2d3000 0076e60d19fe
GPR08: c03fab1dbb80 0178 c03fa722f800 0001
GPR12: c018f5f0 cffb3700 c03fef927f90 
GPR16:  c0f8d468 0050 c004ace0
GPR20: c03ffe743260 2a61 0001 
GPR24: 0076e61c5aa0 3b9aca00  c017cdb0
GPR28: c03fc229 c03ffe2d3000 c018f5f0 c03fa74ca800
NIP [c018f618] tg_unthrottle_up+0x28/0xc0
LR [c0185174] walk_tg_tree_from+0x94/0x120
Call Trace:
[c03fef927610] [c03fe3ad5000] 0xc03fe3ad5000 (unreliable)
[c03fef927690] [c004b8ac] smp_muxed_ipi_message_pass+0x5c/0x70
[c03fef9276e0] [c019d828] unthrottle_cfs_rq+0xe8/0x300
[c03fef927770] [c019dc80] distribute_cfs_runtime+0x160/0x1d0
[c03fef927820] [c019e044] sched_cfs_period_timer+0x154/0x2f0
[c03fef9278a0] [c01f8fc0] __hrtimer_run_queues+0x180/0x430
[c03fef927920] [c01fa2a0] hrtimer_interrupt+0x110/0x300
[c03fef9279d0] [c00291d4] timer_interrupt+0x104/0x2e0
[c03fef927a30] [c0009028] decrementer_common+0x108/0x110

Adding CPUs, or adding empty cgroups makes the situation worse. We haven't
had a chance to dig deeper yet.

Note: The test case makes no attempt to clean up after itself and sometimes
takes my guest down :)

Thanks,
Anton
--

#!/bin/bash -e 

echo 1 > /proc/sys/kernel/nmi_watchdog
echo 1 > /proc/sys/kernel/watchdog_thresh

mkdir -p /sys/fs/cgroup/cpu/base_cgroup
echo 1000 > /sys/fs/cgroup/cpu/base_cgroup/cpu.cfs_period_us
echo 100 > /sys/fs/cgroup/cpu/base_cgroup/cpu.cfs_quota_us

# Create some empty cgroups
for i in $(seq 1 1024)
do
mkdir -p /sys/fs/cgroup/cpu/base_cgroup/$i
done

# Create some cgroups with a CPU soaker
for i in $(seq 1 144)
do
(while :; do :; done ) &
PID=$!
mkdir -p /sys/fs/cgroup/cpu/base_cgroup/$PID
echo $PID > /sys/fs/cgroup/cpu/base_cgroup/$PID/cgroup.procs
done

Re: [PATCH 1/2] ext4: fix warning about stack corruption

[Anton Blanchard]

> > Unfortunately it doesn't appear to work, at least with ppc64le
> > clang:
> >
> > fs/ext4/mballoc.c:2303:17: error: fields must have a constant size:
> > 'variable length array in structure' extension will never be
> > supported ext4_grpblk_t counters[blocksize_bits + 2];  
> 
> My fix for this is in the ext4/dev branch in linux-next, I hope it
> still makes it into v4.13.

Thanks Arnd, I see it now.

Anton

Re: [PATCH 1/2] ext4: fix warning about stack corruption

[Anton Blanchard]

Hi Arnd,

> After commit 62d1034f53e3 ("fortify: use WARN instead of BUG for
> now"), we get a warning about possible stack overflow from a memcpy
> that was not strictly bounded to the size of the local variable:
> 
> inlined from 'ext4_mb_seq_groups_show' at
> fs/ext4/mballoc.c:2322:2: include/linux/string.h:309:9: error:
> '__builtin_memcpy': writing between 161 and 1116 bytes into a region
> of size 160 overflows the destination [-Werror=stringop-overflow=]
> 
> We actually had a bug here that would have been found by the warning,
> but it was already fixed last year in commit 30a9d7afe70e ("ext4: fix
> stack memory corruption with 64k block size").
> 
> This replaces the fixed-length structure on the stack with a
> variable-length structure, using the correct upper bound that tells
> the compiler that everything is really fine here. I also change the
> loop count to check for the same upper bound for consistency, but the
> existing code is already correct here.
> 
> Note that while clang won't allow certain kinds of variable-length
> arrays in structures, this particular instance is fine, as the array
> is at the end of the structure, and the size is strictly bounded.

Unfortunately it doesn't appear to work, at least with ppc64le clang:

fs/ext4/mballoc.c:2303:17: error: fields must have a constant size: 'variable 
length array in structure' extension will never be supported
ext4_grpblk_t counters[blocksize_bits + 2];

Anton

Re: [PATCH] powerpc: Tweak copy selection parameter in __copy_tofrom_user_power7()

[Anton Blanchard]

Hi Andrew,

> Experiments with the netperf benchmark indicated that the size
> selecting VMX-based copies in __copy_tofrom_user_power7() was
> suboptimal on POWER8. Measurements showed that parity was in the
> neighbourhood of 3328 bytes, rather than greater than 4096. The
> change gives a 1.5-2.0% improvement in performance for 4096-byte
> buffers, reducing the relative time spent in
> __copy_tofrom_user_power7() from approximately 7% to approximately 5%
> in the TCP_RR benchmark.

Nice work! All our context switch optimisations we've made over
the last year has likely moved the break even point for this.

Acked-by: Anton Blanchard 

Anton

> Signed-off-by: Andrew Jeffery 
> ---
>  arch/powerpc/lib/copyuser_power7.S | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/powerpc/lib/copyuser_power7.S
> b/arch/powerpc/lib/copyuser_power7.S index a24b4039352c..706b7cc19846
> 100644 --- a/arch/powerpc/lib/copyuser_power7.S
> +++ b/arch/powerpc/lib/copyuser_power7.S
> @@ -82,14 +82,14 @@
>  _GLOBAL(__copy_tofrom_user_power7)
>  #ifdef CONFIG_ALTIVEC
>   cmpldi  r5,16
> - cmpldi  cr1,r5,4096
> + cmpldi  cr1,r5,3328
>  
>   std r3,-STACKFRAMESIZE+STK_REG(R31)(r1)
>   std r4,-STACKFRAMESIZE+STK_REG(R30)(r1)
>   std r5,-STACKFRAMESIZE+STK_REG(R29)(r1)
>  
>   blt .Lshort_copy
> - bgt cr1,.Lvmx_copy
> + bge cr1,.Lvmx_copy
>  #else
>   cmpldi  r5,16
>  

[PATCH] [media] ir-spi: Fix issues with lirc API

[Anton Blanchard]

From: Anton Blanchard 

The ir-spi driver has 2 issues which prevents it from working with
lirc:

1. The ir-spi driver uses 16 bits of SPI data to create one cycle of
the waveform. As such our SPI clock needs to be 16x faster than the
carrier frequency.

The driver is inconsistent in how it currently handles this. It
initializes it to the carrier frequency:

But the commit message has some example code which initialises it
to 16x the carrier frequency:

val = 608000;
ret = ioctl(fd, LIRC_SET_SEND_CARRIER, &val);

To maintain compatibility with lirc, always do the frequency adjustment
in the driver.

2. lirc presents pulses in microseconds, but the ir-spi driver treats
them as cycles of the carrier. Similar to other lirc drivers, do the
conversion with DIV_ROUND_CLOSEST().

Fixes: fe052da49201 ("[media] rc: add support for IR LEDs driven through SPI")
Cc: sta...@vger.kernel.org
Signed-off-by: Anton Blanchard 
---
 drivers/media/rc/ir-spi.c | 9 ++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/media/rc/ir-spi.c b/drivers/media/rc/ir-spi.c
index c8863f36686a..f39cf8cb639f 100644
--- a/drivers/media/rc/ir-spi.c
+++ b/drivers/media/rc/ir-spi.c
@@ -57,10 +57,13 @@ static int ir_spi_tx(struct rc_dev *dev,
 
/* convert the pulse/space signal to raw binary signal */
for (i = 0; i < count; i++) {
+   unsigned int periods;
int j;
u16 val = ((i + 1) % 2) ? idata->pulse : idata->space;
 
-   if (len + buffer[i] >= IR_SPI_MAX_BUFSIZE)
+   periods = DIV_ROUND_CLOSEST(buffer[i] * idata->freq, 100);
+
+   if (len + periods >= IR_SPI_MAX_BUFSIZE)
return -EINVAL;
 
/*
@@ -69,13 +72,13 @@ static int ir_spi_tx(struct rc_dev *dev,
 * contain a space duration.
 */
val = (i % 2) ? idata->space : idata->pulse;
-   for (j = 0; j < buffer[i]; j++)
+   for (j = 0; j < periods; j++)
idata->tx_buf[len++] = val;
}
 
memset(&xfer, 0, sizeof(xfer));
 
-   xfer.speed_hz = idata->freq;
+   xfer.speed_hz = idata->freq * 16;
xfer.len = len * sizeof(*idata->tx_buf);
xfer.tx_buf = idata->tx_buf;
 
-- 
2.11.0

Re: [PATCH] Enabled pstore write for powerpc

[Anton Blanchard]

Hi Ankit,

> After commit c950fd6f201a kernel registers pstore write based on flag
> set. Pstore write for powerpc is broken as flags(PSTORE_FLAGS_DMESG)
> is not set for powerpc architecture. On panic, kernel doesn't write
> message to /fs/pstore/dmesg*(Entry doesn't gets created at all).
> 
> This patch enables pstore write for powerpc architecture by setting
> PSTORE_FLAGS_DMESG flag.
> 
> Fixes:c950fd6f201a pstore: Split pstore fragile flags

Ouch! We've used pstore to shoot customer bugs, so we should also mark
this for stable. Looks like 4.9 onwards?

Anton

> Signed-off-by: Ankit Kumar 
> ---
> 
>  arch/powerpc/kernel/nvram_64.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/powerpc/kernel/nvram_64.c
> b/arch/powerpc/kernel/nvram_64.c index d5e2b83..021db31 100644
> --- a/arch/powerpc/kernel/nvram_64.c
> +++ b/arch/powerpc/kernel/nvram_64.c
> @@ -561,6 +561,7 @@ static ssize_t nvram_pstore_read(u64 *id, enum
> pstore_type_id *type, static struct pstore_info nvram_pstore_info = {
>   .owner = THIS_MODULE,
>   .name = "nvram",
> + .flags = PSTORE_FLAGS_DMESG,
>   .open = nvram_pstore_open,
>   .read = nvram_pstore_read,
>   .write = nvram_pstore_write,

Re: [PATCH] ppc64/kprobe: Fix oops when kprobed on 'stdu' instruction

[Anton Blanchard]

Hi Ravi,

> If we set a kprobe on a 'stdu' instruction on powerpc64, we see a
> kernel OOPS:

Ouch! We should mark this for stable.

Anton

Re: 5-level pagetable patches break ppc64le

[Anton Blanchard]

Hi Kirill,

> > My ppc64le boot tests stopped working as of commit c2febafc6773
> > ("mm: convert generic code to 5-level paging")
> > 
> > We hang part way during boot, just before bringing up the network. I
> > haven't had a chance to narrow it down yet.  
> 
> Please check if patch by this link helps:
> 
> http://lkml.kernel.org/r/20170313052213.11411-1-kirill.shute...@linux.intel.com

It does fix the ppc64le boot hangs, thanks.

Tested-by: Anton Blanchard 

Anton

5-level pagetable patches break ppc64le

[Anton Blanchard]

Hi,

My ppc64le boot tests stopped working as of commit c2febafc6773 ("mm:
convert generic code to 5-level paging")

We hang part way during boot, just before bringing up the network. I
haven't had a chance to narrow it down yet.

Anton

[tip:perf/urgent] perf/core: Rename CONFIG_[UK]PROBE_EVENT to CONFIG_[UK]PROBE_EVENTS

[tip-bot for Anton Blanchard]

Commit-ID:  6b0b7551428e4caae1e2c023a529465a9a9ae2d4
Gitweb: http://git.kernel.org/tip/6b0b7551428e4caae1e2c023a529465a9a9ae2d4
Author: Anton Blanchard 
AuthorDate: Thu, 16 Feb 2017 17:00:50 +1100
Committer:  Ingo Molnar 
CommitDate: Wed, 1 Mar 2017 10:26:39 +0100

perf/core: Rename CONFIG_[UK]PROBE_EVENT to CONFIG_[UK]PROBE_EVENTS

We have uses of CONFIG_UPROBE_EVENT and CONFIG_KPROBE_EVENT as
well as CONFIG_UPROBE_EVENTS and CONFIG_KPROBE_EVENTS.

Consistently use the plurals.

Signed-off-by: Anton Blanchard 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Josh Poimboeuf 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: a...@kernel.org
Cc: alexander.shish...@linux.intel.com
Cc: da...@davemloft.net
Cc: sparcli...@vger.kernel.org
Link: http://lkml.kernel.org/r/20170216060050.20866-1-an...@ozlabs.org
Signed-off-by: Ingo Molnar 
---
 Documentation/trace/kprobetrace.txt |  2 +-
 Documentation/trace/uprobetracer.txt|  2 +-
 arch/powerpc/configs/85xx/kmp204x_defconfig |  2 +-
 arch/s390/configs/default_defconfig |  2 +-
 arch/s390/configs/gcov_defconfig|  2 +-
 arch/s390/configs/performance_defconfig |  2 +-
 arch/s390/defconfig |  2 +-
 kernel/trace/Kconfig|  6 +++---
 kernel/trace/Makefile   |  4 ++--
 kernel/trace/trace.c| 10 +-
 kernel/trace/trace_probe.h  |  4 ++--
 11 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/Documentation/trace/kprobetrace.txt 
b/Documentation/trace/kprobetrace.txt
index e4991fb..41ef9d8 100644
--- a/Documentation/trace/kprobetrace.txt
+++ b/Documentation/trace/kprobetrace.txt
@@ -12,7 +12,7 @@ kprobes can probe (this means, all functions body except for 
__kprobes
 functions). Unlike the Tracepoint based event, this can be added and removed
 dynamically, on the fly.
 
-To enable this feature, build your kernel with CONFIG_KPROBE_EVENT=y.
+To enable this feature, build your kernel with CONFIG_KPROBE_EVENTS=y.
 
 Similar to the events tracer, this doesn't need to be activated via
 current_tracer. Instead of that, add probe points via
diff --git a/Documentation/trace/uprobetracer.txt 
b/Documentation/trace/uprobetracer.txt
index fa7b680..bf526a7c 100644
--- a/Documentation/trace/uprobetracer.txt
+++ b/Documentation/trace/uprobetracer.txt
@@ -7,7 +7,7 @@
 Overview
 
 Uprobe based trace events are similar to kprobe based trace events.
-To enable this feature, build your kernel with CONFIG_UPROBE_EVENT=y.
+To enable this feature, build your kernel with CONFIG_UPROBE_EVENTS=y.
 
 Similar to the kprobe-event tracer, this doesn't need to be activated via
 current_tracer. Instead of that, add probe points via
diff --git a/arch/powerpc/configs/85xx/kmp204x_defconfig 
b/arch/powerpc/configs/85xx/kmp204x_defconfig
index a60..34a4da2 100644
--- a/arch/powerpc/configs/85xx/kmp204x_defconfig
+++ b/arch/powerpc/configs/85xx/kmp204x_defconfig
@@ -210,7 +210,7 @@ CONFIG_DEBUG_SHIRQ=y
 CONFIG_DETECT_HUNG_TASK=y
 CONFIG_SCHEDSTATS=y
 CONFIG_RCU_TRACE=y
-CONFIG_UPROBE_EVENT=y
+CONFIG_UPROBE_EVENTS=y
 CONFIG_CRYPTO_NULL=y
 CONFIG_CRYPTO_PCBC=m
 CONFIG_CRYPTO_MD4=y
diff --git a/arch/s390/configs/default_defconfig 
b/arch/s390/configs/default_defconfig
index 143b1e0..4b176fe 100644
--- a/arch/s390/configs/default_defconfig
+++ b/arch/s390/configs/default_defconfig
@@ -609,7 +609,7 @@ CONFIG_SCHED_TRACER=y
 CONFIG_FTRACE_SYSCALLS=y
 CONFIG_STACK_TRACER=y
 CONFIG_BLK_DEV_IO_TRACE=y
-CONFIG_UPROBE_EVENT=y
+CONFIG_UPROBE_EVENTS=y
 CONFIG_FUNCTION_PROFILER=y
 CONFIG_HIST_TRIGGERS=y
 CONFIG_TRACE_ENUM_MAP_FILE=y
diff --git a/arch/s390/configs/gcov_defconfig b/arch/s390/configs/gcov_defconfig
index f05d2d6..0de46cc 100644
--- a/arch/s390/configs/gcov_defconfig
+++ b/arch/s390/configs/gcov_defconfig
@@ -560,7 +560,7 @@ CONFIG_SCHED_TRACER=y
 CONFIG_FTRACE_SYSCALLS=y
 CONFIG_STACK_TRACER=y
 CONFIG_BLK_DEV_IO_TRACE=y
-CONFIG_UPROBE_EVENT=y
+CONFIG_UPROBE_EVENTS=y
 CONFIG_FUNCTION_PROFILER=y
 CONFIG_HIST_TRIGGERS=y
 CONFIG_TRACE_ENUM_MAP_FILE=y
diff --git a/arch/s390/configs/performance_defconfig 
b/arch/s390/configs/performance_defconfig
index 2358bf3..e167557 100644
--- a/arch/s390/configs/performance_defconfig
+++ b/arch/s390/configs/performance_defconfig
@@ -558,7 +558,7 @@ CONFIG_SCHED_TRACER=y
 CONFIG_FTRACE_SYSCALLS=y
 CONFIG_STACK_TRACER=y
 CONFIG_BLK_DEV_IO_TRACE=y
-CONFIG_UPROBE_EVENT=y
+CONFIG_UPROBE_EVENTS=y
 CONFIG_FUNCTION_PROFILER=y
 CONFIG_HIST_TRIGGERS=y
 CONFIG_TRACE_ENUM_MAP_FILE=y
diff --git a/arch/s390/defconfig b/arch/s390/defconfig
index 68bfd09..97189db 100644
--- a/arch/s390/defconfig
+++ b/arch/s390/defconfig
@@ -179,7 +179,7 @@ CONFIG_FTRACE_SYSCALLS=y
 CONFIG_TRACER_SNAPSHOT_PER_CPU_SWAP=y
 CONFIG_STACK_TRACER=y
 CONFIG_BLK_DEV_IO_TRACE=y
-CONFIG_UPROBE_EVENT=y
+CONFIG_UPROBE_EVENTS=y
 CONFIG_FUNCTION_

Re: [PATCH] powernv:idle: Fix bug due to labeling ambiguity in power_enter_stop

[Anton Blanchard]

Hi Gautham,

> +handle_esl_ec_set:

Unless we want to expose this to things like perf, we might want to
make it a local label (eg .Lxx)

Anton

[PATCH] perf: Rename CONFIG_[UK]PROBE_EVENT to CONFIG_[UK]PROBE_EVENTS

[Anton Blanchard]

From: Anton Blanchard 

We have uses of CONFIG_UPROBE_EVENT and CONFIG_KPROBE_EVENT as
well as CONFIG_UPROBE_EVENTS and CONFIG_KPROBE_EVENTS. Consistently
use the plurals.

Signed-off-by: Anton Blanchard 
---
 Documentation/trace/kprobetrace.txt |  2 +-
 Documentation/trace/uprobetracer.txt|  2 +-
 arch/powerpc/configs/85xx/kmp204x_defconfig |  2 +-
 arch/s390/configs/default_defconfig |  2 +-
 arch/s390/configs/gcov_defconfig|  2 +-
 arch/s390/configs/performance_defconfig |  2 +-
 arch/s390/defconfig |  2 +-
 kernel/trace/Kconfig|  6 +++---
 kernel/trace/Makefile   |  4 ++--
 kernel/trace/trace.c| 10 +-
 kernel/trace/trace_probe.h  |  4 ++--
 11 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/Documentation/trace/kprobetrace.txt 
b/Documentation/trace/kprobetrace.txt
index e4991fb..41ef9d8 100644
--- a/Documentation/trace/kprobetrace.txt
+++ b/Documentation/trace/kprobetrace.txt
@@ -12,7 +12,7 @@ kprobes can probe (this means, all functions body except for 
__kprobes
 functions). Unlike the Tracepoint based event, this can be added and removed
 dynamically, on the fly.
 
-To enable this feature, build your kernel with CONFIG_KPROBE_EVENT=y.
+To enable this feature, build your kernel with CONFIG_KPROBE_EVENTS=y.
 
 Similar to the events tracer, this doesn't need to be activated via
 current_tracer. Instead of that, add probe points via
diff --git a/Documentation/trace/uprobetracer.txt 
b/Documentation/trace/uprobetracer.txt
index fa7b680..bf526a7c 100644
--- a/Documentation/trace/uprobetracer.txt
+++ b/Documentation/trace/uprobetracer.txt
@@ -7,7 +7,7 @@
 Overview
 
 Uprobe based trace events are similar to kprobe based trace events.
-To enable this feature, build your kernel with CONFIG_UPROBE_EVENT=y.
+To enable this feature, build your kernel with CONFIG_UPROBE_EVENTS=y.
 
 Similar to the kprobe-event tracer, this doesn't need to be activated via
 current_tracer. Instead of that, add probe points via
diff --git a/arch/powerpc/configs/85xx/kmp204x_defconfig 
b/arch/powerpc/configs/85xx/kmp204x_defconfig
index a60..34a4da2 100644
--- a/arch/powerpc/configs/85xx/kmp204x_defconfig
+++ b/arch/powerpc/configs/85xx/kmp204x_defconfig
@@ -210,7 +210,7 @@ CONFIG_DEBUG_SHIRQ=y
 CONFIG_DETECT_HUNG_TASK=y
 CONFIG_SCHEDSTATS=y
 CONFIG_RCU_TRACE=y
-CONFIG_UPROBE_EVENT=y
+CONFIG_UPROBE_EVENTS=y
 CONFIG_CRYPTO_NULL=y
 CONFIG_CRYPTO_PCBC=m
 CONFIG_CRYPTO_MD4=y
diff --git a/arch/s390/configs/default_defconfig 
b/arch/s390/configs/default_defconfig
index e0097536..53d7cbb 100644
--- a/arch/s390/configs/default_defconfig
+++ b/arch/s390/configs/default_defconfig
@@ -609,7 +609,7 @@ CONFIG_SCHED_TRACER=y
 CONFIG_FTRACE_SYSCALLS=y
 CONFIG_STACK_TRACER=y
 CONFIG_BLK_DEV_IO_TRACE=y
-CONFIG_UPROBE_EVENT=y
+CONFIG_UPROBE_EVENTS=y
 CONFIG_FUNCTION_PROFILER=y
 CONFIG_HIST_TRIGGERS=y
 CONFIG_TRACE_ENUM_MAP_FILE=y
diff --git a/arch/s390/configs/gcov_defconfig b/arch/s390/configs/gcov_defconfig
index f05d2d6..0de46cc 100644
--- a/arch/s390/configs/gcov_defconfig
+++ b/arch/s390/configs/gcov_defconfig
@@ -560,7 +560,7 @@ CONFIG_SCHED_TRACER=y
 CONFIG_FTRACE_SYSCALLS=y
 CONFIG_STACK_TRACER=y
 CONFIG_BLK_DEV_IO_TRACE=y
-CONFIG_UPROBE_EVENT=y
+CONFIG_UPROBE_EVENTS=y
 CONFIG_FUNCTION_PROFILER=y
 CONFIG_HIST_TRIGGERS=y
 CONFIG_TRACE_ENUM_MAP_FILE=y
diff --git a/arch/s390/configs/performance_defconfig 
b/arch/s390/configs/performance_defconfig
index 2cf8734..e77f0dc 100644
--- a/arch/s390/configs/performance_defconfig
+++ b/arch/s390/configs/performance_defconfig
@@ -558,7 +558,7 @@ CONFIG_SCHED_TRACER=y
 CONFIG_FTRACE_SYSCALLS=y
 CONFIG_STACK_TRACER=y
 CONFIG_BLK_DEV_IO_TRACE=y
-CONFIG_UPROBE_EVENT=y
+CONFIG_UPROBE_EVENTS=y
 CONFIG_FUNCTION_PROFILER=y
 CONFIG_HIST_TRIGGERS=y
 CONFIG_TRACE_ENUM_MAP_FILE=y
diff --git a/arch/s390/defconfig b/arch/s390/defconfig
index d00e368..0732a7f 100644
--- a/arch/s390/defconfig
+++ b/arch/s390/defconfig
@@ -179,7 +179,7 @@ CONFIG_FTRACE_SYSCALLS=y
 CONFIG_TRACER_SNAPSHOT_PER_CPU_SWAP=y
 CONFIG_STACK_TRACER=y
 CONFIG_BLK_DEV_IO_TRACE=y
-CONFIG_UPROBE_EVENT=y
+CONFIG_UPROBE_EVENTS=y
 CONFIG_FUNCTION_PROFILER=y
 CONFIG_TRACE_ENUM_MAP_FILE=y
 CONFIG_KPROBES_SANITY_TEST=y
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index d503800..d4a06e7 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -429,7 +429,7 @@ config BLK_DEV_IO_TRACE
 
  If unsure, say N.
 
-config KPROBE_EVENT
+config KPROBE_EVENTS
depends on KPROBES
depends on HAVE_REGS_AND_STACK_ACCESS_API
bool "Enable kprobes-based dynamic events"
@@ -447,7 +447,7 @@ config KPROBE_EVENT
  This option is also required by perf-probe subcommand of perf tools.
  If you want to use perf tools, this option is strongly recommended.
 
-config UPROBE_EVENT
+config UPROBE_EVENTS
bool &

Re: [PATCH] perf: Fix CONFIG_KPROBE_EVENTS and CONFIG_UPROBE_EVENTS typos

[Anton Blanchard]

Hi Ingo,

> So the names should be fixed, it should be CONFIG_UPROBE_EVENTS and 
> CONFIG_KPROBE_EVENTS throughout the code. It's CONFIG_PERF_EVENTS and 
> CONFIG_PROBE_EVENTS after all and lives in kernel/events/ - all
> plural.
> 
> I didn't notice the misnomer when merging these bits.

Ok, patch to follow.

Anton

[PATCH] perf: Fix CONFIG_KPROBE_EVENTS and CONFIG_UPROBE_EVENTS typos

[Anton Blanchard]

From: Anton Blanchard 

Fix some incorrect Kconfig options, they should be CONFIG_KPROBE_EVENT
and CONFIG_UPROBE_EVENT.

Signed-off-by: Anton Blanchard 
---
 arch/sparc/configs/sparc64_defconfig | 2 +-
 tools/perf/util/probe-file.c | 8 
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/sparc/configs/sparc64_defconfig 
b/arch/sparc/configs/sparc64_defconfig
index b2e650d..f912fd1 100644
--- a/arch/sparc/configs/sparc64_defconfig
+++ b/arch/sparc/configs/sparc64_defconfig
@@ -213,7 +213,7 @@ CONFIG_SCHEDSTATS=y
 # CONFIG_RCU_CPU_STALL_DETECTOR is not set
 CONFIG_SYSCTL_SYSCALL_CHECK=y
 CONFIG_BLK_DEV_IO_TRACE=y
-CONFIG_UPROBE_EVENTS=y
+CONFIG_UPROBE_EVENT=y
 CONFIG_KEYS=y
 CONFIG_CRYPTO_NULL=m
 CONFIG_CRYPTO_TEST=m
diff --git a/tools/perf/util/probe-file.c b/tools/perf/util/probe-file.c
index 436b647..6c74391 100644
--- a/tools/perf/util/probe-file.c
+++ b/tools/perf/util/probe-file.c
@@ -38,9 +38,9 @@ static void print_open_warning(int err, bool uprobe)
const char *config;
 
if (uprobe)
-   config = "CONFIG_UPROBE_EVENTS";
+   config = "CONFIG_UPROBE_EVENT";
else
-   config = "CONFIG_KPROBE_EVENTS";
+   config = "CONFIG_KPROBE_EVENT";
 
pr_warning("%cprobe_events file does not exist"
   " - please rebuild kernel with %s.\n",
@@ -59,8 +59,8 @@ static void print_both_open_warning(int kerr, int uerr)
if (kerr == -ENOTSUP && uerr == -ENOTSUP)
pr_warning("Tracefs or debugfs is not mounted.\n");
else if (kerr == -ENOENT && uerr == -ENOENT)
-   pr_warning("Please rebuild kernel with CONFIG_KPROBE_EVENTS "
-  "or/and CONFIG_UPROBE_EVENTS.\n");
+   pr_warning("Please rebuild kernel with CONFIG_KPROBE_EVENT "
+  "or/and CONFIG_UPROBE_EVENT.\n");
else {
char sbuf[STRERR_BUFSIZE];
pr_warning("Failed to open kprobe events: %s.\n",
-- 
2.9.3

Re: llist code relies on undefined behaviour, upsets llvm/clang

[Anton Blanchard]

Hi Peter,

> Last I checked I couldn't build a x86_64 kernel with llvm. So no, not
> something I've ever ran into.
> 
> Also, I would argue that this is broken in llvm, the kernel very much
> relies on things like this all over the place. Sure, we're way outside
> of what the C language spec says, but who bloody cares ;-)

True, but is there anything preventing gcc from implementing this
optimisation in the future? If we are relying on undefined behaviour we
should have a -fno-strict-* option to cover it.

> If llvm wants to compile the kernel, it needs to learn the C dialect
> the kernel uses.

LLVM has done that before (eg adding -fno-strict-overflow). I don't
think that option covers this case however.

Anton

llist code relies on undefined behaviour, upsets llvm/clang

[Anton Blanchard]

Hi,

I was debugging a hang on a ppc64le kernel built with clang, and it
looks to be undefined behaviour with pointer wrapping in the llist code.

A test case is below. llist_for_each_entry() does container_of() on a
NULL pointer, which wraps our pointer negative, then adds the same
offset back in and expects to get back to NULL. Unfortunately clang
decides that this can never be NULL and optimises it into an infinite
loop.

Build with -DFIX, such that the llist_node has a zero offset from the
start of the struct, and things work.

Is anyone other than ppc64le building kernels with llvm/clang these
days? This should reproduce on ARM64 and x86-64.

Anton
--

#include 

#define __compiler_offsetof(a, b)   \
__builtin_offsetof(a, b)

#undef offsetof
#ifdef __compiler_offsetof
#define offsetof(TYPE, MEMBER)  __compiler_offsetof(TYPE, MEMBER)
#else
#define offsetof(TYPE, MEMBER)  ((size_t)&((TYPE *)0)->MEMBER)
#endif

struct llist_node {
struct llist_node *next;
};

#define container_of(ptr, type, member) ({  \
const typeof( ((type *)0)->member ) *__mptr = (ptr);\
(type *)( (char *)__mptr - offsetof(type,member) );})

#define llist_entry(ptr, type, member)  \
container_of(ptr, type, member)

#define llist_for_each_entry(pos, node, member) \
for ((pos) = llist_entry((node), typeof(*(pos)), member);   \
 &(pos)->member != NULL;\
 (pos) = llist_entry((pos)->member.next, typeof(*(pos)), member))

struct foo {
#ifndef FIX
unsigned long a;
#endif
struct llist_node ll;
};

void working(void);

struct llist_node *ptr;

void bar(void)
{
struct foo *f;

llist_for_each_entry(f, ptr, ll) {
}

working();
}

Re: ext4 filesystem corruption with 4.10-rc2 on ppc64le

[Anton Blanchard]

Hi Ted,

> Anton or Chandan, could you do me a favor and verify whether or not
> 64k block sizes are working for you on ppcle on ext4 by running
> xfstests?  Light duty testing works for me but when I stress ext4 with
> pagesize==blocksize on ppcle64 via xfstests, it blows up.  I suspect
> (but am not sure) it's due to (non-upstream) device driver issues, and
> a verification that you can run xfstests on your ppcle64 systems using
> standard upstream device drivers would be very helpful, since I don't
> have easy console access on the machines I have access to at
> $WORK.  :-(

I fired off an xfstests run, and it looks good. There are 3 failures,
but they seem to be setup issues on my part. I also double checked
those same three failed on 4.8.

Chandan has been running the test suite regularly, and plans to do a
run against mainline too.

Anton

ext4 filesystem corruption with 4.10-rc2 on ppc64le

[Anton Blanchard]

Hi,

I'm consistently seeing ext4 filesystem corruption using a mainline
kernel. It doesn't take much to trigger it - download a ppc64le Ubuntu
cloud image, boot it in KVM and run:

sudo apt-get update
sudo apt-get dist-upgrade
sudo reboot

And it never makes it back up, dying with rather severe filesystem
corruption.

I've narrowed it down to:

64e1c57fa474 ("ext4: Use clean_bdev_aliases() instead of iteration")
e64855c6cfaa ("fs: Add helper to clean bdev aliases under a bh and use it")
ce98321bf7d2 ("fs: Remove unmap_underlying_metadata")

Backing these patches out fixes the issue.

Anton

Re: [PATCH] perf TUI: Don't throw error for zero length symbols

[Anton Blanchard]

Hi Ravi,

> > perf report (with TUI) exits with error when it finds a sample of
> > zero length symbol(i.e. addr == sym->start == sym->end). Actually
> > these are valid samples. Don't exit TUI and show report with such
> > symbols.
> >
> > Link: https://lkml.org/lkml/2016/10/8/189

You can add:

Tested-by: Anton Blanchard 

Also, since this issue makes perf report pretty much useless on
ppc64, can we mark it for stable@, at least to get it into 4.9 where
the ppc64 kernel changes that triggered this appeared?

Anton

> > Reported-by: Anton Blanchard 
> > Signed-off-by: Ravi Bangoria 
> > ---
> >  tools/perf/util/annotate.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
> > index aeb5a44..430d039 100644
> > --- a/tools/perf/util/annotate.c
> > +++ b/tools/perf/util/annotate.c
> > @@ -593,7 +593,8 @@ static int __symbol__inc_addr_samples(struct
> > symbol *sym, struct map *map,
> >
> > pr_debug3("%s: addr=%#" PRIx64 "\n", __func__,
> > map->unmap_ip(map, addr));
> >
> > -   if (addr < sym->start || addr >= sym->end) {
> > +   if ((addr < sym->start || addr >= sym->end) &&
> > +   (addr != sym->end || sym->start != sym->end)) {
> > pr_debug("%s(%d): ERANGE! sym->name=%s, start=%#"
> > PRIx64 ", addr=%#" PRIx64 ", end=%#" PRIx64 "\n", __func__,
> > __LINE__, sym->name, sym->start, addr, sym->end); return -ERANGE;  
> 

Re: perf TUI fails with "failed to process type: 64"

[Anton Blanchard]

Hi,

I forgot about the set of issues below. Michael had a suggested powerpc
fix for 3, but it it would be nice to fix the perf bugs in 1 and 2.

Anton
--

> Updating to mainline as of last night, I started seeing the following
> error when running the perf report TUI:
> 
> 0x46068 [0x8]: failed to process type: 68
> 
> This event is just PERF_RECORD_FINISHED_ROUND:
> 
> 0x46068 [0x8]: event: 68
> .
> . ... raw event: size 8 bytes
> .  :  44 00 00 00 00 00 08 00
> D...
> 
> 0x46068 [0x8]: PERF_RECORD_FINISHED_ROUND
> 
> Which of course is not our error. It took me a while to find the real
> culprit:
> 
>  14c00-14c00 g exc_virt_0x4c00_system_call
> 
> A zero length symbol, which __symbol__inc_addr_samples() barfs on:
> 
> if (addr < sym->start || addr >= sym->end) {
> ...
>   return -ERANGE;
> 
> Seems like we have 3 bugs here:
> 
> 1. Output the real source of the error instead of
> PERF_RECORD_FINISHED_ROUND
> 
> 2. Don't exit the TUI if we find a sample on a zero length symbol
> 
> 3. Why do we have zero length symbols in the first place? Does the
> recent ppc64 exception clean up have something to do with it?
> 
> Anton

Re: [PATCH 1/3] powerpc: Emulation support for load/store instructions on LE

[Anton Blanchard]

Hi,

> kprobe, uprobe, hw-breakpoint and xmon are the only user of
> emulate_step.
> 
> Kprobe / uprobe single-steps instruction if they can't emulate it, so
> there is no problem with them. As I mention, hw-breakpoint is broken.
> However I'm not sure about xmon, I need to check that.

I was mostly concerned that it would impact kprobes. Sounds like we are
ok there.

> So yes, there is no user-visible feature that depends on this.

Aren't hardware breakpoints exposed via perf? I'd call perf
user-visible.

Anton

Re: [PATCH 1/3] powerpc: Emulation support for load/store instructions on LE

[Anton Blanchard]

Hi Ravi,

> emulate_step() uses a number of underlying kernel functions that were
> initially not enabled for LE. This has been rectified since. So, fix
> emulate_step() for LE for the corresponding instructions.

Thanks. Should this be queued up for stable?

Anton

> Reported-by: Anton Blanchard 
> Signed-off-by: Ravi Bangoria 
> ---
>  arch/powerpc/lib/sstep.c | 20 
>  1 file changed, 20 deletions(-)
> 
> diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
> index 3362299..6ca3b90 100644
> --- a/arch/powerpc/lib/sstep.c
> +++ b/arch/powerpc/lib/sstep.c
> @@ -1807,8 +1807,6 @@ int __kprobes emulate_step(struct pt_regs
> *regs, unsigned int instr) goto instr_done;
>  
>   case LARX:
> - if (regs->msr & MSR_LE)
> - return 0;
>   if (op.ea & (size - 1))
>   break;  /* can't handle
> misaligned */ err = -EFAULT;
> @@ -1832,8 +1830,6 @@ int __kprobes emulate_step(struct pt_regs
> *regs, unsigned int instr) goto ldst_done;
>  
>   case STCX:
> - if (regs->msr & MSR_LE)
> - return 0;
>   if (op.ea & (size - 1))
>   break;  /* can't handle
> misaligned */ err = -EFAULT;
> @@ -1859,8 +1855,6 @@ int __kprobes emulate_step(struct pt_regs
> *regs, unsigned int instr) goto ldst_done;
>  
>   case LOAD:
> - if (regs->msr & MSR_LE)
> - return 0;
>   err = read_mem(®s->gpr[op.reg], op.ea, size,
> regs); if (!err) {
>   if (op.type & SIGNEXT)
> @@ -1872,8 +1866,6 @@ int __kprobes emulate_step(struct pt_regs
> *regs, unsigned int instr) 
>  #ifdef CONFIG_PPC_FPU
>   case LOAD_FP:
> - if (regs->msr & MSR_LE)
> - return 0;
>   if (size == 4)
>   err = do_fp_load(op.reg, do_lfs, op.ea,
> size, regs); else
> @@ -1882,15 +1874,11 @@ int __kprobes emulate_step(struct pt_regs
> *regs, unsigned int instr) #endif
>  #ifdef CONFIG_ALTIVEC
>   case LOAD_VMX:
> - if (regs->msr & MSR_LE)
> - return 0;
>   err = do_vec_load(op.reg, do_lvx, op.ea & ~0xfUL,
> regs); goto ldst_done;
>  #endif
>  #ifdef CONFIG_VSX
>   case LOAD_VSX:
> - if (regs->msr & MSR_LE)
> - return 0;
>   err = do_vsx_load(op.reg, do_lxvd2x, op.ea, regs);
>   goto ldst_done;
>  #endif
> @@ -1913,8 +1901,6 @@ int __kprobes emulate_step(struct pt_regs
> *regs, unsigned int instr) goto instr_done;
>  
>   case STORE:
> - if (regs->msr & MSR_LE)
> - return 0;
>   if ((op.type & UPDATE) && size == sizeof(long) &&
>   op.reg == 1 && op.update_reg == 1 &&
>   !(regs->msr & MSR_PR) &&
> @@ -1927,8 +1913,6 @@ int __kprobes emulate_step(struct pt_regs
> *regs, unsigned int instr) 
>  #ifdef CONFIG_PPC_FPU
>   case STORE_FP:
> - if (regs->msr & MSR_LE)
> - return 0;
>   if (size == 4)
>   err = do_fp_store(op.reg, do_stfs, op.ea,
> size, regs); else
> @@ -1937,15 +1921,11 @@ int __kprobes emulate_step(struct pt_regs
> *regs, unsigned int instr) #endif
>  #ifdef CONFIG_ALTIVEC
>   case STORE_VMX:
> - if (regs->msr & MSR_LE)
> - return 0;
>   err = do_vec_store(op.reg, do_stvx, op.ea & ~0xfUL,
> regs); goto ldst_done;
>  #endif
>  #ifdef CONFIG_VSX
>   case STORE_VSX:
> - if (regs->msr & MSR_LE)
> - return 0;
>   err = do_vsx_store(op.reg, do_stxvd2x, op.ea, regs);
>   goto ldst_done;
>  #endif

[tip:perf/urgent] perf jit: Fix build issue on Ubuntu

[tip-bot for Anton Blanchard]

Commit-ID:  53613e005496234bb684e5db551fbcededa73999
Gitweb: http://git.kernel.org/tip/53613e005496234bb684e5db551fbcededa73999
Author: Anton Blanchard 
AuthorDate: Thu, 13 Oct 2016 13:20:43 +1100
Committer:  Arnaldo Carvalho de Melo 
CommitDate: Mon, 17 Oct 2016 11:25:34 -0300

perf jit: Fix build issue on Ubuntu

When building on Ubuntu 16.04, I get the following error:

Makefile:49: *** the openjdk development package appears to me missing, install 
and try again.  Stop.

The problem is that update-java-alternatives has multiple spaces between
fields, and cut treats each space as a new delimiter:

java-1.8.0-openjdk-ppc64el 1081   
/usr/lib/jvm/java-1.8.0-openjdk-ppc64el

Fix this by using awk, which handles this fine.

Signed-off-by: Anton Blanchard 
Reviewed-by: Stephane Eranian 
Cc: Alexander Shishkin 
Cc: Peter Zijlstra 
Link: 
http://lkml.kernel.org/r/1476325243-15788-1-git-send-email-an...@ozlabs.org
Signed-off-by: Arnaldo Carvalho de Melo 
---
 tools/perf/jvmti/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/jvmti/Makefile b/tools/perf/jvmti/Makefile
index 5ce61a1..df14e6b 100644
--- a/tools/perf/jvmti/Makefile
+++ b/tools/perf/jvmti/Makefile
@@ -36,7 +36,7 @@ SOLIBEXT=so
 # The following works at least on fedora 23, you may need the next
 # line for other distros.
 ifneq (,$(wildcard /usr/sbin/update-java-alternatives))
-JDIR=$(shell /usr/sbin/update-java-alternatives -l | head -1 | cut -d ' ' -f 3)
+JDIR=$(shell /usr/sbin/update-java-alternatives -l | head -1 | awk '{print 
$$3}')
 else
   ifneq (,$(wildcard /usr/sbin/alternatives))
 JDIR=$(shell alternatives --display java | tail -1 | cut -d' ' -f 5 | sed 
's%/jre/bin/java.%%g')

[PATCH] perf jit: Fix build issue on Ubuntu

[Anton Blanchard]

From: Anton Blanchard 

When building on Ubuntu 16.04, I get the following error:

Makefile:49: *** the openjdk development package appears to me missing, install 
and try again.  Stop.

The problem is that update-java-alternatives has multiple spaces between
fields, and cut treats each space as a new delimiter:

java-1.8.0-openjdk-ppc64el 1081   
/usr/lib/jvm/java-1.8.0-openjdk-ppc64el

Fix this by using awk, which handles this fine.

Signed-off-by: Anton Blanchard 
---
 tools/perf/jvmti/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/jvmti/Makefile b/tools/perf/jvmti/Makefile
index 5ce61a1..df14e6b 100644
--- a/tools/perf/jvmti/Makefile
+++ b/tools/perf/jvmti/Makefile
@@ -36,7 +36,7 @@ SOLIBEXT=so
 # The following works at least on fedora 23, you may need the next
 # line for other distros.
 ifneq (,$(wildcard /usr/sbin/update-java-alternatives))
-JDIR=$(shell /usr/sbin/update-java-alternatives -l | head -1 | cut -d ' ' -f 3)
+JDIR=$(shell /usr/sbin/update-java-alternatives -l | head -1 | awk '{print 
$$3}')
 else
   ifneq (,$(wildcard /usr/sbin/alternatives))
 JDIR=$(shell alternatives --display java | tail -1 | cut -d' ' -f 5 | sed 
's%/jre/bin/java.%%g')
-- 
2.7.4

Re: perf TUI fails with "failed to process type: 64"

[Anton Blanchard]

Hi Michael,

> >  14c00-14c00 g exc_virt_0x4c00_system_call  
>^
>What's this? The address? If so it's wrong?

Offset into the binary I think, there's one 64kB page of ELF gunk at
the start.

> Seems likely. But I can't see why.
> 
> AFAICS we have never emitted a size for those symbols:
> 
> Old:
> $ nm --print-size build/vmlinux | grep -w system_call_relon_pSeries
> c0004c00 T system_call_relon_pSeries
> 
> New:
> $ nm --print-size build/vmlinux | grep -w exc_virt_0x4c00_system_call
> c0004c00 T exc_virt_0x4c00_system_call
> 
> 
> It also doesn't look like we're emitting another symbol with the same
> address, which has caused confusion in the past:
> 
> Old:
> c0004c00 T exc_virt_0x4c00_system_call
> c0004d00 T exc_virt_0x4d00_single_step
> 
> New:
> c0004c00 T system_call_relon_pSeries
> c0004d00 T single_step_relon_pSeries
> 
> So more digging required.

Thanks for checking, it's starting to sound like a perf bug.

Anton

perf TUI fails with "failed to process type: 64"

[Anton Blanchard]

Hi,

Updating to mainline as of last night, I started seeing the following
error when running the perf report TUI:

0x46068 [0x8]: failed to process type: 68

This event is just PERF_RECORD_FINISHED_ROUND:

0x46068 [0x8]: event: 68
.
. ... raw event: size 8 bytes
.  :  44 00 00 00 00 00 08 00  D...

0x46068 [0x8]: PERF_RECORD_FINISHED_ROUND

Which of course is not our error. It took me a while to find the real
culprit:

 14c00-14c00 g exc_virt_0x4c00_system_call

A zero length symbol, which __symbol__inc_addr_samples() barfs on:

if (addr < sym->start || addr >= sym->end) {
...
return -ERANGE;

Seems like we have 3 bugs here:

1. Output the real source of the error instead of PERF_RECORD_FINISHED_ROUND

2. Don't exit the TUI if we find a sample on a zero length symbol

3. Why do we have zero length symbols in the first place? Does the recent
   ppc64 exception clean up have something to do with it?

Anton

Re: [PATCH 0/3] Fix crypto/vmx/p8_ghash memory corruption

[Anton Blanchard]

Hi Marcelo

> This series fixes the memory corruption found by Jan Stancek in
> 4.8-rc7. The problem however also affects previous versions of the
> driver.

If it affects previous versions, please add the lines in the sign off to
get it into the stable kernels.

Anton

Re: [PATCH] Work around for enabling CONFIG_CMDLINE on ppc64le

[Anton Blanchard]

Hi,

> But I can't merge that patch.
> 
> Our options are one or both of:
>  - get GCC fixed and backport the fix to the compilers we care about.
>  - blacklist the broken compiler versions.
> 
> Is there a GCC bug filed for this?

Likely: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71709

We need confirmation this patch fixes the 6.x issue too and that we need
a backport.

Anton

[tip:perf/urgent] perf symbols: Fix annotation of objects with debuginfo files

[tip-bot for Anton Blanchard]

Commit-ID:  50de1a0c54cdbc69a6dbcbc323f53daf95a4050e
Gitweb: http://git.kernel.org/tip/50de1a0c54cdbc69a6dbcbc323f53daf95a4050e
Author: Anton Blanchard 
AuthorDate: Sat, 13 Aug 2016 11:55:33 +1000
Committer:  Arnaldo Carvalho de Melo 
CommitDate: Mon, 15 Aug 2016 16:49:57 -0300

perf symbols: Fix annotation of objects with debuginfo files

Commit 73cdf0c6ea9c ("perf symbols: Record text offset in dso
to calculate objdump address") started storing the offset of
the text section for all DSOs:

   if (elf_section_by_name(elf, &ehdr, &tshdr, ".text", NULL))
   dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;

Unfortunately this breaks debuginfo files, because we need to calculate
the offset of the text section in the associated executable file. As a
result perf annotate returns junk for all debuginfo files.

Fix this by using runtime_ss->elf which should point at the executable
when parsing a debuginfo file.

Signed-off-by: Anton Blanchard 
Reviewed-by: Naveen N. Rao 
Tested-by: Wang Nan 
Cc: Peter Zijlstra 
Cc: Ravi Bangoria 
Cc: sta...@vger.kernel.org # v4.6+
Fixes: 73cdf0c6ea9c ("perf symbols: Record text offset in dso to calculate 
objdump address")
Link: http://lkml.kernel.org/r/20160813115533.6de17912@kryten
Signed-off-by: Arnaldo Carvalho de Melo 
---
 tools/perf/util/symbol-elf.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index a34321e..a811c13 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -837,7 +837,8 @@ int dso__load_sym(struct dso *dso, struct map *map,
sec = syms_ss->symtab;
shdr = syms_ss->symshdr;
 
-   if (elf_section_by_name(elf, &ehdr, &tshdr, ".text", NULL))
+   if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
+   ".text", NULL))
dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
 
if (runtime_ss->opdsec)

[PATCH v2] perf symbols: Fix annotation of objects with debuginfo files

[Anton Blanchard]

From: Anton Blanchard 

Commit 73cdf0c6ea9c ("perf symbols: Record text offset in dso
to calculate objdump address") started storing the offset of
the text section for all DSOs: 

   if (elf_section_by_name(elf, &ehdr, &tshdr, ".text", NULL))
   dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;

Unfortunately this breaks debuginfo files, because we need to calculate
the offset of the text section in the associated executable file. As a
result perf annotate returns junk for all debuginfo files.

Fix this by using runtime_ss->elf which should point at the executable
when parsing a debuginfo file.

Cc: sta...@vger.kernel.org # v4.6+
Fixes: 73cdf0c6ea9c ("perf symbols: Record text offset in dso to calculate 
objdump address")
Signed-off-by: Anton Blanchard 
---

v2: Fix from Naveen

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index a34321e..a811c13 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -837,7 +837,8 @@ int dso__load_sym(struct dso *dso, struct map *map,
sec = syms_ss->symtab;
shdr = syms_ss->symshdr;
 
-   if (elf_section_by_name(elf, &ehdr, &tshdr, ".text", NULL))
+   if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
+   ".text", NULL))
dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
 
if (runtime_ss->opdsec)

[PATCH] perf symbols: Fix annotation of objects with debuginfo files

[Anton Blanchard]

From: Anton Blanchard 

Commit 73cdf0c6ea9c ("perf symbols: Record text offset in dso
to calculate objdump address") started storing the offset of
the text section for all DSOs: 

   if (elf_section_by_name(elf, &ehdr, &tshdr, ".text", NULL))
   dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;

Unfortunately this breaks debuginfo files, because we need to calculate
the offset of the text section in the associated executable file. As a
result perf annotate returns junk for all debuginfo files.

Fix this by using runtime_ss->elf which should point at the executable
when parsing a debuginfo file.

Cc: sta...@vger.kernel.org # v4.6+
Fixes: 73cdf0c6ea9c ("perf symbols: Record text offset in dso to calculate 
objdump address")
Signed-off-by: Anton Blanchard 
---

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index a34321e..9e36073 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -837,7 +837,7 @@ int dso__load_sym(struct dso *dso, struct map *map,
sec = syms_ss->symtab;
shdr = syms_ss->symshdr;
 
-   if (elf_section_by_name(elf, &ehdr, &tshdr, ".text", NULL))
+   if (elf_section_by_name(runtime_ss->elf, &ehdr, &tshdr, ".text", NULL))
dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
 
if (runtime_ss->opdsec)

Re: [PATCH 2/2] perf ppc64le: Fix probe location when using DWARF

[Anton Blanchard]

Hi Arnaldo,

> Anyway, Anton, does this fix the problem for you?

Yes it does, thanks!

Anton

Re: [PATCH 2/2] perf ppc64le: Fix probe location when using DWARF

[Anton Blanchard]

Hi,

> Powerpc has Global Entry Point and Local Entry Point for functions.
> LEP catches call from both the GEP and the LEP. Symbol table of ELF
> contains GEP and Offset from which we can calculate LEP, but debuginfo
> does not have LEP info.
> 
> Currently, perf prioritize symbol table over dwarf to probe on LEP
> for ppc64le. But when user tries to probe with function parameter,
> we fall back to using dwarf(i.e. GEP) and when function called via
> LEP, probe will never hit.

This patch causes a build failure for me on ppc64le:

libperf.a(libperf-in.o): In function `arch__post_process_probe_trace_events':

tools/perf/arch/powerpc/util/sym-handling.c:109: undefined reference to 
`get_target_map'

Anton

> For example:
>   $ objdump -d vmlinux
> ...
> do_sys_open():
> c02eb4a0:   e8 00 4c 3c addis   r2,r12,232
> c02eb4a4:   60 00 42 38 addir2,r2,96
> c02eb4a8:   a6 02 08 7c mflrr0
> c02eb4ac:   d0 ff 41 fb std r26,-48(r1)
> 
>   $ sudo ./perf probe do_sys_open
>   $ sudo cat /sys/kernel/debug/tracing/kprobe_events
> p:probe/do_sys_open _text+3060904
> 
>   $ sudo ./perf probe 'do_sys_open filename:string'
>   $ sudo cat /sys/kernel/debug/tracing/kprobe_events
> p:probe/do_sys_open _text+3060896 filename_string=+0(%gpr4):string
> 
> For second case, perf probed on GEP. So when function will be called
> via LEP, probe won't hit.
> 
>   $ sudo ./perf record -a -e probe:do_sys_open ls
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 0.195 MB perf.data ]
> 
> To resolve this issue, let's not prioritize symbol table, let perf
> decide what it wants to use. Perf is already converting GEP to LEP
> when it uses symbol table. When perf uses debuginfo, let it find
> LEP offset form symbol table. This way we fall back to probe on LEP
> for all cases.
> 
> After patch:
>   $ sudo ./perf probe 'do_sys_open filename:string'
>   $ sudo cat /sys/kernel/debug/tracing/kprobe_events
> p:probe/do_sys_open _text+3060904 filename_string=+0(%gpr4):string
> 
>   $ sudo ./perf record -a -e probe:do_sys_open ls
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 0.197 MB perf.data (11 samples)
> ]
> 
> Signed-off-by: Ravi Bangoria 
> ---
>  tools/perf/arch/powerpc/util/sym-handling.c | 27
> + tools/perf/util/probe-event.c   |
> 37 -
> tools/perf/util/probe-event.h   |  6 - 3 files
> changed, 49 insertions(+), 21 deletions(-)
> 
> diff --git a/tools/perf/arch/powerpc/util/sym-handling.c
> b/tools/perf/arch/powerpc/util/sym-handling.c index c6d0f91..8d4dc97
> 100644 --- a/tools/perf/arch/powerpc/util/sym-handling.c
> +++ b/tools/perf/arch/powerpc/util/sym-handling.c
> @@ -54,10 +54,6 @@ int arch__compare_symbol_names(const char *namea,
> const char *nameb) #endif
>  
>  #if defined(_CALL_ELF) && _CALL_ELF == 2
> -bool arch__prefers_symtab(void)
> -{
> - return true;
> -}
>  
>  #ifdef HAVE_LIBELF_SUPPORT
>  void arch__sym_update(struct symbol *s, GElf_Sym *sym)
> @@ -100,4 +96,27 @@ void arch__fix_tev_from_maps(struct
> perf_probe_event *pev, tev->point.offset += lep_offset;
>   }
>  }
> +
> +void arch__post_process_probe_trace_events(struct perf_probe_event
> *pev,
> +int ntevs)
> +{
> + struct probe_trace_event *tev;
> + struct map *map;
> + struct symbol *sym = NULL;
> + struct rb_node *tmp;
> + int i = 0;
> +
> + map = get_target_map(pev->target, pev->uprobes);
> + if (!map || map__load(map, NULL) < 0)
> + return;
> +
> + for (i = 0; i < ntevs; i++) {
> + tev = &pev->tevs[i];
> + map__for_each_symbol(map, sym, tmp) {
> + if (map->unmap_ip(map, sym->start) ==
> tev->point.address)
> + arch__fix_tev_from_maps(pev, tev,
> map, sym);
> + }
> + }
> +}
> +
>  #endif
> diff --git a/tools/perf/util/probe-event.c
> b/tools/perf/util/probe-event.c index 4e215e7..5efa535 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -178,7 +178,7 @@ static struct map *kernel_get_module_map(const
> char *module) return NULL;
>  }
>  
> -static struct map *get_target_map(const char *target, bool user)
> +struct map *get_target_map(const char *target, bool user)
>  {
>   /* Init maps of given executable or kernel */
>   if (user)
> @@ -703,19 +703,32 @@ post_process_kernel_probe_trace_events(struct
> probe_trace_event *tevs, return skipped;
>  }
>  
> +void __weak
> +arch__post_process_probe_trace_events(struct perf_probe_event *pev
> __maybe_unused,
> +   int ntevs __maybe_unused)
> +{
> +}
> +
>  /* Post processing the probe events */
> -static int post_process_probe_trace_events(struct probe_trace_event
> *tevs, +static int post_p

Re: [patch V2 30/67] powerpc/numa: Convert to hotplug state machine

[Anton Blanchard]

> > I noticed tip started failing in my CI environment which tests on
> > QEMU. The failure bisected to commit
> > 425209e0abaf2c6e3a90ce4fedb935c10652bf80  
> 
> That's very useful, thanks Anton!
> 
> I have removed this commit from the series for the time being,
> refactored the followup commits (there was one trivial conflict). We
> can re-try this patch when a fix is found.

Thanks Ingo, my tests are passing again after your last push.

Anton

Re: [patch V2 30/67] powerpc/numa: Convert to hotplug state machine

[Anton Blanchard]

Hi Anna-Maria,

> >> Install the callbacks via the state machine and let the core invoke
> >> the callbacks on the already online CPUs.  
> >
> > This is causing an oops on ppc64le QEMU, looks like a NULL
> > pointer:  
> 
> Did you tested it against tip WIP.hotplug?

I noticed tip started failing in my CI environment which tests on QEMU.
The failure bisected to commit 425209e0abaf2c6e3a90ce4fedb935c10652bf80

It reproduces running ppc64le QEMU on a x86-64 box. On Ubuntu:

sudo apt-get install qemu-system-ppc gcc-powerpc64le-linux-gnu

make ARCH=powerpc pseries_le_defconfig

make ARCH=powerpc CROSS_COMPILE=powerpc64le-linux-gnu- vmlinux -j4

qemu-system-ppc64 -nographic -vga none -kernel vmlinux 

Anton

Re: [patch V2 30/67] powerpc/numa: Convert to hotplug state machine

[Anton Blanchard]

Hi,

> From: Sebastian Andrzej Siewior 
> 
> Install the callbacks via the state machine and let the core invoke
> the callbacks on the already online CPUs.

This is causing an oops on ppc64le QEMU, looks like a NULL pointer:

percpu: Embedded 3 pages/cpu @c0001fe0 s145816 r0 d50792 u1048576
Unable to handle kernel paging request for data at address 0x1e08
Faulting instruction address: 0xc01e6b78
Oops: Kernel access of bad area, sig: 11 [#1]
SMP NR_CPUS=2048 NUMA pSeries
Modules linked in:
CPU: 0 PID: 0 Comm: swapper Not tainted 4.7.0-rc7-00198-g425209e #14
task: c0d82a00 ti: c0dc4000 task.ti: c0dc4000
NIP: c01e6b78 LR: c01e6df4 CTR: 
REGS: c0dc7b60 TRAP: 0300   Not tainted  (4.7.0-rc7-00198-g425209e)
MSR: 82001033   CR: 44000220  XER: 
CFAR: 8468 DAR: 1e08 DSISR: 4000 SOFTE: 0 
GPR00: 0006 c0dc7de0 c0dc6c00  
GPR04:   c0001fe1fb70 0010 
GPR08: c0dfe918 c0e50dd0 c0e56c00 0001 
GPR12:  cfe0 0060 00f1d618 
GPR16: 00efccd8 00efcb20 fffd  
GPR20: 1f15 c0dfa8e0 c0ccfafc c0dfeb18 
GPR24: c0dfee34 c0ccfaf8  0001 
GPR28: c0ebad20 c0ccfb00  c0001fe1fb00 
NIP [c01e6b78] local_memory_node+0x18/0x80
LR [c01e6df4] __build_all_zonelists+0x214/0x2d0
Call Trace:
[c0dc7de0] [c01e6ccc] __build_all_zonelists+0xec/0x2d0 
(unreliable)
[c0dc7e70] [c0c39fbc] build_all_zonelists_init+0x1c/0x3c
[c0dc7e90] [c0282acc] build_all_zonelists+0x17c/0x18c
[c0dc7f00] [c0c13c54] start_kernel+0x18c/0x514
[c0dc7f90] [c0008c60] start_here_common+0x20/0xa0
Instruction dump:
38810178 7f63db78 48769171 6000 4bfffd2c 6042 3c4c00be 384200a0 
3d420009 78631f24 392aa1d0 7c69182a <81231e08> 38631e00 2b890002 419d001c 

Anton

> Signed-off-by: Sebastian Andrzej Siewior 
> Cc: Andrew Morton 
> Cc: Benjamin Herrenschmidt 
> Cc: Bharata B Rao 
> Cc: Christophe Jaillet 
> Cc: Linus Torvalds 
> Cc: Michael Ellerman 
> Cc: Nikunj A Dadhania 
> Cc: Paul Mackerras 
> Cc: Peter Zijlstra 
> Cc: Raghavendra K T 
> Cc: Thomas Gleixner 
> Cc: linuxppc-...@lists.ozlabs.org
> Signed-off-by: Anna-Maria Gleixner 
> ---
>  arch/powerpc/mm/numa.c | 46
> --
> include/linux/cpuhotplug.h |  1 + 2 files changed, 17 insertions(+),
> 30 deletions(-)
> 
> diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
> index 669a15e..d48ac48 100644
> --- a/arch/powerpc/mm/numa.c
> +++ b/arch/powerpc/mm/numa.c
> @@ -581,30 +581,22 @@ static void verify_cpu_node_mapping(int cpu,
> int node) }
>  }
>  
> -static int cpu_numa_callback(struct notifier_block *nfb, unsigned
> long action,
> -  void *hcpu)
> +/* Must run before sched domains notifier. */
> +static int ppc_numa_cpu_prepare(unsigned int cpu)
>  {
> - unsigned long lcpu = (unsigned long)hcpu;
> - int ret = NOTIFY_DONE, nid;
> + int nid;
>  
> - switch (action) {
> - case CPU_UP_PREPARE:
> - case CPU_UP_PREPARE_FROZEN:
> - nid = numa_setup_cpu(lcpu);
> - verify_cpu_node_mapping((int)lcpu, nid);
> - ret = NOTIFY_OK;
> - break;
> + nid = numa_setup_cpu(cpu);
> + verify_cpu_node_mapping(cpu, nid);
> + return 0;
> +}
> +
> +static int ppc_numa_cpu_dead(unsigned int cpu)
> +{
>  #ifdef CONFIG_HOTPLUG_CPU
> - case CPU_DEAD:
> - case CPU_DEAD_FROZEN:
> - case CPU_UP_CANCELED:
> - case CPU_UP_CANCELED_FROZEN:
> - unmap_cpu_from_node(lcpu);
> - ret = NOTIFY_OK;
> - break;
> + unmap_cpu_from_node(cpu);
>  #endif
> - }
> - return ret;
> + return 0;
>  }
>  
>  /*
> @@ -913,11 +905,6 @@ static void __init
> dump_numa_memory_topology(void) }
>  }
>  
> -static struct notifier_block ppc64_numa_nb = {
> - .notifier_call = cpu_numa_callback,
> - .priority = 1 /* Must run before sched domains notifier. */
> -};
> -
>  /* Initialize NODE_DATA for a node on the local memory */
>  static void __init setup_node_data(int nid, u64 start_pfn, u64
> end_pfn) {
> @@ -953,7 +940,7 @@ static void __init setup_node_data(int nid, u64
> start_pfn, u64 end_pfn) 
>  void __init initmem_init(void)
>  {
> - int nid, cpu;
> + int nid;
>  
>   max_low_pfn = memblock_end_of_DRAM() >> PAGE_SHIFT;
>   max_pfn = max_low_pfn;
> @@ -985,15 +972,14 @@ void __init initmem_init(void)
>   setup_node_to_cpumask_map();
>  
>   reset_numa_cpu_lookup_table();
> - register_cpu_notifier(&ppc64_numa_nb);
> +
>   /*
>* We need the numa_cpu_lookup_table to

Re: [patch 10/15] sched/migration: Move calc_load_migrate() into CPU_DYING

[Anton Blanchard]

Hi Thomas,

> It really does not matter when we fold the load for the outgoing cpu.
> It's almost dead anyway, so there is no harm if we fail to fold the
> few microseconds which are required for going fully away.

We are seeing the load average shoot up when hot unplugging CPUs (+1
for every CPU we offline) on ppc64. This reproduces on bare metal as
well as inside a KVM guest. A bisect points at this commit.

As an example, a completely idle box with 128 CPUS and 112 hot
unplugged:

# uptime
 04:35:30 up  1:23,  2 users,  load average: 112.43, 122.94, 125.54

Anton

[PATCH 1/2] exit: Quieten greatest stack depth printk

[Anton Blanchard]

From: Anton Blanchard 

Many targets enable CONFIG_DEBUG_STACK_USAGE, and while the information
is useful, it isn't worthy of pr_warn(). Reduce it to pr_info().

Signed-off-by: Anton Blanchard 
---
 kernel/exit.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/exit.c b/kernel/exit.c
index 9e6e135..bbdef62 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -639,7 +639,7 @@ static void check_stack_usage(void)
 
spin_lock(&low_water_lock);
if (free < lowest_to_date) {
-   pr_warn("%s (%d) used greatest stack depth: %lu bytes left\n",
+   pr_info("%s (%d) used greatest stack depth: %lu bytes left\n",
current->comm, task_pid_nr(current), free);
lowest_to_date = free;
}
-- 
2.7.4

[PATCH 2/2] mm: workingset: printk missing log level, use pr_info()

[Anton Blanchard]

From: Anton Blanchard 

commit 612e44939c3c ("mm: workingset: eviction buckets for bigmem/lowbit
machines") added a printk without a log level. Quieten it by using
pr_info().

Signed-off-by: Anton Blanchard 
---
 mm/workingset.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/workingset.c b/mm/workingset.c
index 8a75f8d..5772775 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -491,7 +491,7 @@ static int __init workingset_init(void)
max_order = fls_long(totalram_pages - 1);
if (max_order > timestamp_bits)
bucket_order = max_order - timestamp_bits;
-   printk("workingset: timestamp_bits=%d max_order=%d bucket_order=%u\n",
+   pr_info("workingset: timestamp_bits=%d max_order=%d bucket_order=%u\n",
   timestamp_bits, max_order, bucket_order);
 
ret = list_lru_init_key(&workingset_shadow_nodes, &shadow_nodes_key);
-- 
2.7.4

Re: [PATCH] powerpc: inline current_stack_pointer()

[Anton Blanchard]

Hi,

> current_stack_pointeur() is a single instruction function. it
> It is not worth breaking the execution flow with a bl/blr for a
> single instruction

Check out bfe9a2cfe91a ("powerpc: Reimplement __get_SP() as a function
not a define") to see why we made it a function.

Anton

[tip:sched/core] sched/cpuacct: Check for NULL when using task_pt_regs()

[tip-bot for Anton Blanchard]

Commit-ID:  bd92883051a0228cc34996b8e766111ba10c9aac
Gitweb: http://git.kernel.org/tip/bd92883051a0228cc34996b8e766111ba10c9aac
Author: Anton Blanchard 
AuthorDate: Wed, 6 Apr 2016 21:59:50 +1000
Committer:  Ingo Molnar 
CommitDate: Wed, 13 Apr 2016 13:22:37 +0200

sched/cpuacct: Check for NULL when using task_pt_regs()

task_pt_regs() can return NULL for kernel threads, so add a check.
This fixes an oops at boot on ppc64.

Reported-and-Tested-by: Srikar Dronamraju 
Tested-by: Zhao Lei 
Signed-off-by: Anton Blanchard 
Acked-by: Zhao Lei 
Cc: Linus Torvalds 
Cc: Michael Ellerman 
Cc: Peter Zijlstra 
Cc: Stephen Rothwell 
Cc: Thomas Gleixner 
Cc: efa...@gmx.de
Cc: hte...@gmail.com
Cc: linuxppc-...@lists.ozlabs.org
Cc: t...@kernel.org
Cc: yangds.f...@cn.fujitsu.com
Link: http://lkml.kernel.org/r/20160406215950.04bc3f0b@kryten
Signed-off-by: Ingo Molnar 
---
 kernel/sched/cpuacct.c | 7 +++
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c
index df947e0..41f85c4 100644
--- a/kernel/sched/cpuacct.c
+++ b/kernel/sched/cpuacct.c
@@ -316,12 +316,11 @@ static struct cftype files[] = {
 void cpuacct_charge(struct task_struct *tsk, u64 cputime)
 {
struct cpuacct *ca;
-   int index;
+   int index = CPUACCT_USAGE_SYSTEM;
+   struct pt_regs *regs = task_pt_regs(tsk);
 
-   if (user_mode(task_pt_regs(tsk)))
+   if (regs && user_mode(regs))
index = CPUACCT_USAGE_USER;
-   else
-   index = CPUACCT_USAGE_SYSTEM;
 
rcu_read_lock();
 

[PATCH] sched/cpuacct: Check for NULL when using task_pt_regs()

[Anton Blanchard]

task_pt_regs() can return NULL for kernel threads, so add a check.
This fixes an oops at boot on ppc64.

Fixes: d740037fac70 ("sched/cpuacct: Split usage accounting into user_usage and 
sys_usage")
Signed-off-by: Anton Blanchard 
Reported-and-Tested-by: Srikar Dronamraju 
---

diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c
index df947e0..41f85c4 100644
--- a/kernel/sched/cpuacct.c
+++ b/kernel/sched/cpuacct.c
@@ -316,12 +316,11 @@ static struct cftype files[] = {
 void cpuacct_charge(struct task_struct *tsk, u64 cputime)
 {
struct cpuacct *ca;
-   int index;
+   int index = CPUACCT_USAGE_SYSTEM;
+   struct pt_regs *regs = task_pt_regs(tsk);
 
-   if (user_mode(task_pt_regs(tsk)))
+   if (regs && user_mode(regs))
index = CPUACCT_USAGE_USER;
-   else
-   index = CPUACCT_USAGE_SYSTEM;
 
rcu_read_lock();
 

[PATCH] sched/cpuacct: Check for NULL when using task_pt_regs()

[Anton Blanchard]

Hi Peter,

> Ah, so sometihng like:
> 
>   struct pt_regs *regs = task_pt_regs();
>   int index = CPUACCT_USAGE_SYSTEM;
> 
>   if (regs && user_mode(regs))
>   index = CPUACCT_USAGE_USER;
> 
> should work, right?

Looks good, and the patch below does fix the oops for me.

Anton
--

task_pt_regs() can return NULL for kernel threads, so add a check.
This fixes an oops at boot on ppc64.

Signed-off-by: Anton Blanchard 
---

diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c
index df947e0..41f85c4 100644
--- a/kernel/sched/cpuacct.c
+++ b/kernel/sched/cpuacct.c
@@ -316,12 +316,11 @@ static struct cftype files[] = {
 void cpuacct_charge(struct task_struct *tsk, u64 cputime)
 {
struct cpuacct *ca;
-   int index;
+   int index = CPUACCT_USAGE_SYSTEM;
+   struct pt_regs *regs = task_pt_regs(tsk);
 
-   if (user_mode(task_pt_regs(tsk)))
+   if (regs && user_mode(regs))
index = CPUACCT_USAGE_USER;
-   else
-   index = CPUACCT_USAGE_SYSTEM;
 
rcu_read_lock();
 

Re: [tip:sched/core] sched/cpuacct: Split usage accounting into user_usage and sys_usage

[Anton Blanchard]

Hi,

> > >  void cpuacct_charge(struct task_struct *tsk, u64 cputime)
> > >  {
> > >   struct cpuacct *ca;
> > > + int index;
> > > +
> > > + if (user_mode(task_pt_regs(tsk)))
> > > + index = CPUACCT_USAGE_USER;
> > > + else
> > > + index = CPUACCT_USAGE_SYSTEM;

This is oopsing because PowerPC task_pt_regs() returns NULL for
kernel threads.

Anton

[tip:perf/urgent] perf jit: genelf makes assumptions about endian

[tip-bot for Anton Blanchard]

Commit-ID:  9f56c092b99b40ce3cf4c6d0134ff7e513c9f1a6
Gitweb: http://git.kernel.org/tip/9f56c092b99b40ce3cf4c6d0134ff7e513c9f1a6
Author: Anton Blanchard 
AuthorDate: Tue, 29 Mar 2016 17:59:44 +1100
Committer:  Arnaldo Carvalho de Melo 
CommitDate: Wed, 30 Mar 2016 18:12:06 -0300

perf jit: genelf makes assumptions about endian

Commit 9b07e27f88b9 ("perf inject: Add jitdump mmap injection support")
incorrectly assumed that PowerPC is big endian only.

Simplify things by consolidating the define of GEN_ELF_ENDIAN and checking
for __BYTE_ORDER == __BIG_ENDIAN.

The PowerPC checks were also incorrect, they do not match what gcc
emits. We should first look for __powerpc64__, then __powerpc__.

Signed-off-by: Anton Blanchard 
Acked-by: Michael Ellerman 
Cc: Carl Love 
Cc: Stephane Eranian 
Cc: Sukadev Bhattiprolu 
Cc: linuxppc-...@lists.ozlabs.org
Fixes: 9b07e27f88b9 ("perf inject: Add jitdump mmap injection support")
Link: http://lkml.kernel.org/r/20160329175944.33a211cc@kryten
Signed-off-by: Arnaldo Carvalho de Melo 
---
 tools/perf/util/genelf.h | 24 ++--
 1 file changed, 10 insertions(+), 14 deletions(-)

diff --git a/tools/perf/util/genelf.h b/tools/perf/util/genelf.h
index cd67e64..2fbeb59 100644
--- a/tools/perf/util/genelf.h
+++ b/tools/perf/util/genelf.h
@@ -9,36 +9,32 @@ int jit_add_debug_info(Elf *e, uint64_t code_addr, void 
*debug, int nr_debug_ent
 
 #if   defined(__arm__)
 #define GEN_ELF_ARCH   EM_ARM
-#define GEN_ELF_ENDIAN ELFDATA2LSB
 #define GEN_ELF_CLASS  ELFCLASS32
 #elif defined(__aarch64__)
 #define GEN_ELF_ARCH   EM_AARCH64
-#define GEN_ELF_ENDIAN ELFDATA2LSB
 #define GEN_ELF_CLASS  ELFCLASS64
 #elif defined(__x86_64__)
 #define GEN_ELF_ARCH   EM_X86_64
-#define GEN_ELF_ENDIAN ELFDATA2LSB
 #define GEN_ELF_CLASS  ELFCLASS64
 #elif defined(__i386__)
 #define GEN_ELF_ARCH   EM_386
-#define GEN_ELF_ENDIAN ELFDATA2LSB
 #define GEN_ELF_CLASS  ELFCLASS32
-#elif defined(__ppcle__)
-#define GEN_ELF_ARCH   EM_PPC
-#define GEN_ELF_ENDIAN ELFDATA2LSB
-#define GEN_ELF_CLASS  ELFCLASS64
-#elif defined(__powerpc__)
-#define GEN_ELF_ARCH   EM_PPC64
-#define GEN_ELF_ENDIAN ELFDATA2MSB
-#define GEN_ELF_CLASS  ELFCLASS64
-#elif defined(__powerpcle__)
+#elif defined(__powerpc64__)
 #define GEN_ELF_ARCH   EM_PPC64
-#define GEN_ELF_ENDIAN ELFDATA2LSB
 #define GEN_ELF_CLASS  ELFCLASS64
+#elif defined(__powerpc__)
+#define GEN_ELF_ARCH   EM_PPC
+#define GEN_ELF_CLASS  ELFCLASS32
 #else
 #error "unsupported architecture"
 #endif
 
+#if __BYTE_ORDER == __BIG_ENDIAN
+#define GEN_ELF_ENDIAN ELFDATA2MSB
+#else
+#define GEN_ELF_ENDIAN ELFDATA2LSB
+#endif
+
 #if GEN_ELF_CLASS == ELFCLASS64
 #define elf_newehdrelf64_newehdr
 #define elf_getshdrelf64_getshdr

[PATCH] perf jit: genelf makes assumptions about endian

[Anton Blanchard]

Commit 9b07e27f88b9 ("perf inject: Add jitdump mmap injection support")
incorrectly assumed that PowerPC is big endian only.

Simplify things by consolidating the define of GEN_ELF_ENDIAN and checking
for __BYTE_ORDER == __BIG_ENDIAN.

The PowerPC checks were also incorrect, they do not match what gcc
emits. We should first look for __powerpc64__, then __powerpc__.

Fixes: 9b07e27f88b9 ("perf inject: Add jitdump mmap injection support")
Signed-off-by: Anton Blanchard 
---

diff --git a/tools/perf/util/genelf.h b/tools/perf/util/genelf.h
index cd67e64..2fbeb59 100644
--- a/tools/perf/util/genelf.h
+++ b/tools/perf/util/genelf.h
@@ -9,36 +9,32 @@ int jit_add_debug_info(Elf *e, uint64_t code_addr, void 
*debug, int nr_debug_ent
 
 #if   defined(__arm__)
 #define GEN_ELF_ARCH   EM_ARM
-#define GEN_ELF_ENDIAN ELFDATA2LSB
 #define GEN_ELF_CLASS  ELFCLASS32
 #elif defined(__aarch64__)
 #define GEN_ELF_ARCH   EM_AARCH64
-#define GEN_ELF_ENDIAN ELFDATA2LSB
 #define GEN_ELF_CLASS  ELFCLASS64
 #elif defined(__x86_64__)
 #define GEN_ELF_ARCH   EM_X86_64
-#define GEN_ELF_ENDIAN ELFDATA2LSB
 #define GEN_ELF_CLASS  ELFCLASS64
 #elif defined(__i386__)
 #define GEN_ELF_ARCH   EM_386
-#define GEN_ELF_ENDIAN ELFDATA2LSB
 #define GEN_ELF_CLASS  ELFCLASS32
-#elif defined(__ppcle__)
-#define GEN_ELF_ARCH   EM_PPC
-#define GEN_ELF_ENDIAN ELFDATA2LSB
-#define GEN_ELF_CLASS  ELFCLASS64
-#elif defined(__powerpc__)
-#define GEN_ELF_ARCH   EM_PPC64
-#define GEN_ELF_ENDIAN ELFDATA2MSB
-#define GEN_ELF_CLASS  ELFCLASS64
-#elif defined(__powerpcle__)
+#elif defined(__powerpc64__)
 #define GEN_ELF_ARCH   EM_PPC64
-#define GEN_ELF_ENDIAN ELFDATA2LSB
 #define GEN_ELF_CLASS  ELFCLASS64
+#elif defined(__powerpc__)
+#define GEN_ELF_ARCH   EM_PPC
+#define GEN_ELF_CLASS  ELFCLASS32
 #else
 #error "unsupported architecture"
 #endif
 
+#if __BYTE_ORDER == __BIG_ENDIAN
+#define GEN_ELF_ENDIAN ELFDATA2MSB
+#else
+#define GEN_ELF_ENDIAN ELFDATA2LSB
+#endif
+
 #if GEN_ELF_CLASS == ELFCLASS64
 #define elf_newehdrelf64_newehdr
 #define elf_getshdrelf64_getshdr

Re: [PATCH] powerpc: fix dedotify for binutils >= 2.26

[Anton Blanchard]

> Since binutils 2.26 BFD is doing suffix merging on STRTAB sections.
> But dedotify modifies the symbol names in place, which can also modify
> unrelated symbols with a name that matches a suffix of a dotted
> name.  To remove the leading dot of a symbol name we can just
> increment the pointer into the STRTAB section instead.

Thanks Andreas.

> Signed-off-by: Andreas Schwab 

I think we should get it into stable too.

Anton

> ---
>  arch/powerpc/kernel/module_64.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/kernel/module_64.c
> b/arch/powerpc/kernel/module_64.c index ac64ffd..08b7a40 100644
> --- a/arch/powerpc/kernel/module_64.c
> +++ b/arch/powerpc/kernel/module_64.c
> @@ -340,7 +340,7 @@ static void dedotify(Elf64_Sym *syms, unsigned
> int numsyms, char *strtab) if (name[0] == '.') {
>   if (strcmp(name+1, "TOC.") == 0)
>   syms[i].st_shndx = SHN_ABS;
> - memmove(name, name+1, strlen(name));
> + syms[i].st_name++;
>   }
>   }
>   }

Re: [PATCH 3/9] powerpc32: checksum_wrappers_64 becomes checksum_wrappers

[Anton Blanchard]

Hi Scott,

> I wonder why it was 64-bit specific in the first place.

I think it was part of a series where I added my 64bit assembly checksum
routines, and I didn't step back and think that the wrapper code would
be useful on 32 bit.

Anton
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Re: [PATCH v2] Makefile: Fix detection of clang when cross-compiling

[Anton Blanchard]

Hi,

>  > When the host's C compiler is clang, and when attempting to
>  > cross-compile Linux e.g. to MIPS with mipsel-linux-gcc, the
>  > Makefile would incorrectly detect the use of clang, which
>  > resulted in clang-specific flags being passed to
>  > mipsel-linux-gcc.
>  >
>  > This can be verified under Debian by installing the "clang"
>  > package, and then using it as the default compiler with:
>  > sudo update-alternatives --config cc
>  >
>  > This patch moves the detection of clang after the $(CC)
>  > variable is initialized to the name of the cross-compiler, so
>  > that the check applies
>  > to the cross-compiler and not the host's C compiler.
>  >
>  > v2: Move the detection of clang after the inclusion of the
>  > arch/*/Makefile (as they might set $(CROSS_COMPILE))
>  >
>  > Signed-off-by: Paul Cercueil  >
> 
> Applied to kbuild.git#kbuild. I will push it after v4.1-rc1
> becomes available, though.
> 
> Drat. I wish I saw this earlier.
> 
> This breaks patches which check for the value of COMPILER in 
> arch/*/Makefile. This detection must be performed before the
> inclusion of the arch Makefile.
> 
> Can I move this to after the initialization of CC but before the
> include?
> 
> I'm not sure that being able to define the default compiler per arch
> is necessary. But I know I need to be able to add arch specific flags
> for clang.

I can confirm the patch breaks ppc64le clang builds.

Anton
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Re: [RFC PATCH] powerpc/numa: initialize distance lookup table from drconf path

[Anton Blanchard]

Hi Nikunj,

> > Thanks for the patch. Have we tested that this doesn't regress the
> > non dynamic representation?
> 
> Yes, that is tested. And works as expected.

Great, you can add:

Acked-by: Anton Blanchard 

Anton
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Re: [RFC PATCH] powerpc/numa: initialize distance lookup table from drconf path

[Anton Blanchard]

Hi Nikunj,

> From: Nikunj A Dadhania 
> 
> powerpc/numa: initialize distance lookup table from drconf path
> 
> In some situations, a NUMA guest that supports
> ibm,dynamic-memory-reconfiguration node will end up having flat NUMA
> distances between nodes. This is because of two problems in the
> current code.

Thanks for the patch. Have we tested that this doesn't regress the
non dynamic representation?

Regards,
Anton

> 1) Different representations of associativity lists.
> 
>There is an assumption about the associativity list in
>initialize_distance_lookup_table(). Associativity list has two
> forms:
> 
>a) [cpu,memory]@x/ibm,associativity has following
>   format:
> 
> 
>b)
> ibm,dynamic-reconfiguration-memory/ibm,associativity-lookup-arrays
> 
>  
>M = the number of associativity lists
>N = the number of entries per associativity list
> 
>Fix initialize_distance_lookup_table() so that it does not assume
>"case a". And update the caller to skip the length field before
>sending the associativity list.
> 
> 2) Distance table not getting updated from drconf path.
> 
>Node distance table will not get initialized in certain cases as
>ibm,dynamic-reconfiguration-memory path does not initialize the
>lookup table.
> 
>Call initialize_distance_lookup_table() from drconf path with
>appropriate associativity list.
> 
> Reported-by: Bharata B Rao 
> Signed-off-by: Nikunj A Dadhania 
> ---
>  arch/powerpc/mm/numa.c | 16 +---
>  1 file changed, 13 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
> index 5e80621..8b9502a 100644
> --- a/arch/powerpc/mm/numa.c
> +++ b/arch/powerpc/mm/numa.c
> @@ -225,7 +225,7 @@ static void initialize_distance_lookup_table(int
> nid, for (i = 0; i < distance_ref_points_depth; i++) {
>   const __be32 *entry;
>  
> - entry =
> &associativity[be32_to_cpu(distance_ref_points[i])];
> + entry =
> &associativity[be32_to_cpu(distance_ref_points[i]) - 1];
> distance_lookup_table[nid][i] = of_read_number(entry, 1); }
>  }
> @@ -248,8 +248,12 @@ static int associativity_to_nid(const __be32
> *associativity) nid = -1;
>  
>   if (nid > 0 &&
> - of_read_number(associativity, 1) >=
> distance_ref_points_depth)
> - initialize_distance_lookup_table(nid, associativity);
> + of_read_number(associativity, 1) >=
> distance_ref_points_depth) {
> + /*
> +  * Skip the length field and send start of
> associativity array
> +  */
> + initialize_distance_lookup_table(nid, associativity
> + 1);
> + }
>  
>  out:
>   return nid;
> @@ -507,6 +511,12 @@ static int of_drconf_to_nid_single(struct
> of_drconf_cell *drmem, 
>   if (nid == 0x || nid >= MAX_NUMNODES)
>   nid = default_nid;
> +
> + if (nid > 0) {
> + index = drmem->aa_index * aa->array_sz;
> + initialize_distance_lookup_table(nid,
> +
> &aa->arrays[index]);
> + }
>   }
>  
>   return nid;

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Re: [PATCH V3 09/13] selftests, powerpc: Add test for DSCR value inheritence across fork

[Anton Blanchard]

Hi Anshuman,

Thanks for getting these testcases into the kernel.

> This patch adds a test to verify that the changed DSCR value inside
> any process would be inherited to it's child process across the fork
> system call.

One issue I do notice (a bug in my original test cases too), is that we
don't restore the DSCR on exit. I'm not sure we need to go to the
trouble of saving and restoring it, but we should at least get it back
to 0 when done.

Also a tiny nit, no need for a newline in perror():

open() failed
: Permission denied

With those changes you can add:

Signed-off-by: Anton Blanchard 

to the patches based on my testcases.

Anton
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[PATCH] compiler: add support for gcc 6

[Anton Blanchard]

gcc has recently bumped its major version and this is causing kernel
build errors. Create include/linux/compiler-gcc6.h which is a copy
of compiler-gcc5.h, minus a few comments that no longer apply.

Signed-off-by: Anton Blanchard 
---

I'm told the versioning scheme in gcc has changed, and to expect
much more rev'ing of the major version. We should probably rethink
if we need a separate file per major version.

diff --git a/include/linux/compiler-gcc6.h b/include/linux/compiler-gcc6.h
new file mode 100644
index 000..ba064fa
--- /dev/null
+++ b/include/linux/compiler-gcc6.h
@@ -0,0 +1,59 @@
+#ifndef __LINUX_COMPILER_H
+#error "Please don't include  directly, include 
 instead."
+#endif
+
+#define __used __attribute__((__used__))
+#define __must_check   __attribute__((warn_unused_result))
+#define __compiler_offsetof(a, b)  __builtin_offsetof(a, b)
+
+/* Mark functions as cold. gcc will assume any path leading to a call
+   to them will be unlikely.  This means a lot of manual unlikely()s
+   are unnecessary now for any paths leading to the usual suspects
+   like BUG(), printk(), panic() etc. [but let's keep them for now for
+   older compilers]
+
+   gcc also has a __attribute__((__hot__)) to move hot functions into
+   a special section, but I don't see any sense in this right now in
+   the kernel context */
+#define __cold __attribute__((__cold__))
+
+#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
+
+#ifndef __CHECKER__
+# define __compiletime_warning(message) __attribute__((warning(message)))
+# define __compiletime_error(message) __attribute__((error(message)))
+#endif /* __CHECKER__ */
+
+/*
+ * Mark a position in code as unreachable.  This can be used to
+ * suppress control flow warnings after asm blocks that transfer
+ * control elsewhere.
+ */
+#define unreachable() __builtin_unreachable()
+
+/* Mark a function definition as prohibited from being cloned. */
+#define __noclone  __attribute__((__noclone__))
+
+/*
+ * Tell the optimizer that something else uses this function or variable.
+ */
+#define __visible __attribute__((externally_visible))
+
+/*
+ * GCC 'asm goto' miscompiles certain code sequences:
+ *
+ *   http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
+ *
+ * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
+ *
+ * (asm goto is automatically volatile - the naming reflects this.)
+ */
+#define asm_volatile_goto(x...)do { asm goto(x); asm (""); } while (0)
+
+#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP
+#define __HAVE_BUILTIN_BSWAP32__
+#define __HAVE_BUILTIN_BSWAP64__
+#define __HAVE_BUILTIN_BSWAP16__
+#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */
+
+#define KASAN_ABI_VERSION 4
-- 
2.1.0

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[tip:locking/core] jump_label: Allow asm/ jump_label.h to be included in assembly

[tip-bot for Anton Blanchard]

Commit-ID:  55dd0df781e58ec23d218376ea4a676e7362a98c
Gitweb: http://git.kernel.org/tip/55dd0df781e58ec23d218376ea4a676e7362a98c
Author: Anton Blanchard 
AuthorDate: Thu, 9 Apr 2015 13:51:30 +1000
Committer:  Ingo Molnar 
CommitDate: Thu, 9 Apr 2015 09:40:23 +0200

jump_label: Allow asm/jump_label.h to be included in assembly

Wrap asm/jump_label.h for all archs with #ifndef __ASSEMBLY__.
Since these are kernel only headers, we don't need #ifdef
__KERNEL__ so can simplify things a bit.

If an architecture wants to use jump labels in assembly, it
will still need to define a macro to create the __jump_table
entries (see ARCH_STATIC_BRANCH in the powerpc asm/jump_label.h
for an example).

Signed-off-by: Anton Blanchard 
Acked-by: Peter Zijlstra (Intel) 
Cc: Andrew Morton 
Cc: Linus Torvalds 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: b...@kernel.crashing.org
Cc: catalin.mari...@arm.com
Cc: da...@davemloft.net
Cc: heiko.carst...@de.ibm.com
Cc: jba...@akamai.com
Cc: li...@arm.linux.org.uk
Cc: linuxppc-...@lists.ozlabs.org
Cc: liu...@gmail.com
Cc: mgor...@suse.de
Cc: mma...@suse.cz
Cc: m...@ellerman.id.au
Cc: pau...@samba.org
Cc: r...@linux-mips.org
Cc: rost...@goodmis.org
Cc: schwidef...@de.ibm.com
Cc: will.dea...@arm.com
Link: http://lkml.kernel.org/r/1428551492-21977-1-git-send-email-an...@samba.org
Signed-off-by: Ingo Molnar 
---
 arch/arm/include/asm/jump_label.h   | 5 ++---
 arch/arm64/include/asm/jump_label.h | 8 
 arch/mips/include/asm/jump_label.h  | 7 +++
 arch/s390/include/asm/jump_label.h  | 3 +++
 arch/sparc/include/asm/jump_label.h | 5 ++---
 arch/x86/include/asm/jump_label.h   | 5 ++---
 6 files changed, 16 insertions(+), 17 deletions(-)

diff --git a/arch/arm/include/asm/jump_label.h 
b/arch/arm/include/asm/jump_label.h
index 70f9b9b..5f337dc 100644
--- a/arch/arm/include/asm/jump_label.h
+++ b/arch/arm/include/asm/jump_label.h
@@ -1,7 +1,7 @@
 #ifndef _ASM_ARM_JUMP_LABEL_H
 #define _ASM_ARM_JUMP_LABEL_H
 
-#ifdef __KERNEL__
+#ifndef __ASSEMBLY__
 
 #include 
 
@@ -27,8 +27,6 @@ l_yes:
return true;
 }
 
-#endif /* __KERNEL__ */
-
 typedef u32 jump_label_t;
 
 struct jump_entry {
@@ -37,4 +35,5 @@ struct jump_entry {
jump_label_t key;
 };
 
+#endif  /* __ASSEMBLY__ */
 #endif
diff --git a/arch/arm64/include/asm/jump_label.h 
b/arch/arm64/include/asm/jump_label.h
index 076a1c7..c0e5165 100644
--- a/arch/arm64/include/asm/jump_label.h
+++ b/arch/arm64/include/asm/jump_label.h
@@ -18,11 +18,12 @@
  */
 #ifndef __ASM_JUMP_LABEL_H
 #define __ASM_JUMP_LABEL_H
+
+#ifndef __ASSEMBLY__
+
 #include 
 #include 
 
-#ifdef __KERNEL__
-
 #define JUMP_LABEL_NOP_SIZEAARCH64_INSN_SIZE
 
 static __always_inline bool arch_static_branch(struct static_key *key)
@@ -39,8 +40,6 @@ l_yes:
return true;
 }
 
-#endif /* __KERNEL__ */
-
 typedef u64 jump_label_t;
 
 struct jump_entry {
@@ -49,4 +48,5 @@ struct jump_entry {
jump_label_t key;
 };
 
+#endif  /* __ASSEMBLY__ */
 #endif /* __ASM_JUMP_LABEL_H */
diff --git a/arch/mips/include/asm/jump_label.h 
b/arch/mips/include/asm/jump_label.h
index fdbff44..608aa57 100644
--- a/arch/mips/include/asm/jump_label.h
+++ b/arch/mips/include/asm/jump_label.h
@@ -8,9 +8,9 @@
 #ifndef _ASM_MIPS_JUMP_LABEL_H
 #define _ASM_MIPS_JUMP_LABEL_H
 
-#include 
+#ifndef __ASSEMBLY__
 
-#ifdef __KERNEL__
+#include 
 
 #define JUMP_LABEL_NOP_SIZE 4
 
@@ -39,8 +39,6 @@ l_yes:
return true;
 }
 
-#endif /* __KERNEL__ */
-
 #ifdef CONFIG_64BIT
 typedef u64 jump_label_t;
 #else
@@ -53,4 +51,5 @@ struct jump_entry {
jump_label_t key;
 };
 
+#endif  /* __ASSEMBLY__ */
 #endif /* _ASM_MIPS_JUMP_LABEL_H */
diff --git a/arch/s390/include/asm/jump_label.h 
b/arch/s390/include/asm/jump_label.h
index 58642fd..2b77e23 100644
--- a/arch/s390/include/asm/jump_label.h
+++ b/arch/s390/include/asm/jump_label.h
@@ -1,6 +1,8 @@
 #ifndef _ASM_S390_JUMP_LABEL_H
 #define _ASM_S390_JUMP_LABEL_H
 
+#ifndef __ASSEMBLY__
+
 #include 
 
 #define JUMP_LABEL_NOP_SIZE 6
@@ -39,4 +41,5 @@ struct jump_entry {
jump_label_t key;
 };
 
+#endif  /* __ASSEMBLY__ */
 #endif
diff --git a/arch/sparc/include/asm/jump_label.h 
b/arch/sparc/include/asm/jump_label.h
index ec2e2e2..cc9b04a 100644
--- a/arch/sparc/include/asm/jump_label.h
+++ b/arch/sparc/include/asm/jump_label.h
@@ -1,7 +1,7 @@
 #ifndef _ASM_SPARC_JUMP_LABEL_H
 #define _ASM_SPARC_JUMP_LABEL_H
 
-#ifdef __KERNEL__
+#ifndef __ASSEMBLY__
 
 #include 
 
@@ -22,8 +22,6 @@ l_yes:
return true;
 }
 
-#endif /* __KERNEL__ */
-
 typedef u32 jump_label_t;
 
 struct jump_entry {
@@ -32,4 +30,5 @@ struct jump_entry {
jump_label_t key;
 };
 
+#endif  /* __ASSEMBLY__ */
 #endif
diff --git a/arch/x86/include/asm/jump_label.h 
b/arch/x86/include/asm/jump_label.h
index 6a2cefb..a4c1cf7 100644
--- a/arch/x86/include/asm/jump_label.h
+++ b/arch/x86/include/asm/jump_label.h
@@ -1,7 +1,7 @@
 #ifndef _ASM_X86_JUMP_LABEL_H
 #define _ASM_X86_JUMP_LABEL_H
 
-#ifdef __KER

[tip:locking/core] powerpc, jump_label: Include linux/ jump_label.h to get HAVE_JUMP_LABEL define

[tip-bot for Anton Blanchard]

Commit-ID:  58995a9a5b292458f94a2356b8c878230fa56fe0
Gitweb: http://git.kernel.org/tip/58995a9a5b292458f94a2356b8c878230fa56fe0
Author: Anton Blanchard 
AuthorDate: Thu, 9 Apr 2015 13:51:32 +1000
Committer:  Ingo Molnar 
CommitDate: Thu, 9 Apr 2015 09:40:29 +0200

powerpc, jump_label: Include linux/jump_label.h to get HAVE_JUMP_LABEL define

Commit 1bc9e47aa8e4 ("powerpc/jump_label: Use HAVE_JUMP_LABEL")
converted uses of CONFIG_JUMP_LABEL to HAVE_JUMP_LABEL in
some assembly files.

HAVE_JUMP_LABEL is defined in linux/jump_label.h, so we need to
include this or we always get the non jump label fallback code.

Signed-off-by: Anton Blanchard 
Acked-by: Michael Ellerman 
Acked-by: Peter Zijlstra (Intel) 
Cc: Andrew Morton 
Cc: Linus Torvalds 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: b...@kernel.crashing.org
Cc: catalin.mari...@arm.com
Cc: da...@davemloft.net
Cc: heiko.carst...@de.ibm.com
Cc: jba...@akamai.com
Cc: li...@arm.linux.org.uk
Cc: linuxppc-...@lists.ozlabs.org
Cc: liu...@gmail.com
Cc: mgor...@suse.de
Cc: mma...@suse.cz
Cc: pau...@samba.org
Cc: r...@linux-mips.org
Cc: rost...@goodmis.org
Cc: schwidef...@de.ibm.com
Cc: will.dea...@arm.com
Fixes: 1bc9e47aa8e4 ("powerpc/jump_label: Use HAVE_JUMP_LABEL")
Link: http://lkml.kernel.org/r/1428551492-21977-3-git-send-email-an...@samba.org
Signed-off-by: Ingo Molnar 
---
 arch/powerpc/platforms/powernv/opal-wrappers.S | 2 +-
 arch/powerpc/platforms/pseries/hvCall.S| 2 +-
 arch/powerpc/platforms/pseries/lpar.c  | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S 
b/arch/powerpc/platforms/powernv/opal-wrappers.S
index 0509bca..fcbe899 100644
--- a/arch/powerpc/platforms/powernv/opal-wrappers.S
+++ b/arch/powerpc/platforms/powernv/opal-wrappers.S
@@ -9,11 +9,11 @@
  * 2 of the License, or (at your option) any later version.
  */
 
+#include 
 #include 
 #include 
 #include 
 #include 
-#include 
 
.section".text"
 
diff --git a/arch/powerpc/platforms/pseries/hvCall.S 
b/arch/powerpc/platforms/pseries/hvCall.S
index ccd53f9..74b5b8e 100644
--- a/arch/powerpc/platforms/pseries/hvCall.S
+++ b/arch/powerpc/platforms/pseries/hvCall.S
@@ -7,12 +7,12 @@
  * as published by the Free Software Foundation; either version
  * 2 of the License, or (at your option) any later version.
  */
+#include 
 #include 
 #include 
 #include 
 #include 
 #include 
-#include 
 
.section".text"

diff --git a/arch/powerpc/platforms/pseries/lpar.c 
b/arch/powerpc/platforms/pseries/lpar.c
index b5682fd..b7a67e3 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -26,7 +26,7 @@
 #include 
 #include 
 #include 
-#include 
+#include 
 #include 
 #include 
 #include 
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[tip:locking/core] jump_label: Allow jump labels to be used in assembly

[tip-bot for Anton Blanchard]

Commit-ID:  c0ccf6f99e3a43b87980c9df7da48427885206d0
Gitweb: http://git.kernel.org/tip/c0ccf6f99e3a43b87980c9df7da48427885206d0
Author: Anton Blanchard 
AuthorDate: Thu, 9 Apr 2015 13:51:31 +1000
Committer:  Ingo Molnar 
CommitDate: Thu, 9 Apr 2015 09:40:24 +0200

jump_label: Allow jump labels to be used in assembly

To use jump labels in assembly we need the HAVE_JUMP_LABEL
define, so we select a fallback version if the toolchain does
not support them.

Modify linux/jump_label.h so it can be included by assembly
files. We also need to add -DCC_HAVE_ASM_GOTO to KBUILD_AFLAGS.

Signed-off-by: Anton Blanchard 
Acked-by: Peter Zijlstra (Intel) 
Cc: Andrew Morton 
Cc: Linus Torvalds 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: b...@kernel.crashing.org
Cc: catalin.mari...@arm.com
Cc: da...@davemloft.net
Cc: heiko.carst...@de.ibm.com
Cc: jba...@akamai.com
Cc: li...@arm.linux.org.uk
Cc: linuxppc-...@lists.ozlabs.org
Cc: liu...@gmail.com
Cc: mgor...@suse.de
Cc: mma...@suse.cz
Cc: m...@ellerman.id.au
Cc: pau...@samba.org
Cc: r...@linux-mips.org
Cc: rost...@goodmis.org
Cc: schwidef...@de.ibm.com
Cc: will.dea...@arm.com
Link: http://lkml.kernel.org/r/1428551492-21977-2-git-send-email-an...@samba.org
Signed-off-by: Ingo Molnar 
---
 Makefile   |  1 +
 include/linux/jump_label.h | 21 +
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/Makefile b/Makefile
index 9fab639..a2aa475 100644
--- a/Makefile
+++ b/Makefile
@@ -779,6 +779,7 @@ KBUILD_ARFLAGS := $(call ar-option,D)
 # check for 'asm goto'
 ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC)), y)
KBUILD_CFLAGS += -DCC_HAVE_ASM_GOTO
+   KBUILD_AFLAGS += -DCC_HAVE_ASM_GOTO
 endif
 
 include $(srctree)/scripts/Makefile.kasan
diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index 98f923b6..f4de473 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -45,6 +45,12 @@
  * same as using STATIC_KEY_INIT_FALSE.
  */
 
+#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
+# define HAVE_JUMP_LABEL
+#endif
+
+#ifndef __ASSEMBLY__
+
 #include 
 #include 
 #include 
@@ -55,7 +61,7 @@ extern bool static_key_initialized;
"%s used before call to jump_label_init", \
__func__)
 
-#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
+#ifdef HAVE_JUMP_LABEL
 
 struct static_key {
atomic_t enabled;
@@ -66,13 +72,18 @@ struct static_key {
 #endif
 };
 
-# include 
-# define HAVE_JUMP_LABEL
 #else
 struct static_key {
atomic_t enabled;
 };
-#endif /* CC_HAVE_ASM_GOTO && CONFIG_JUMP_LABEL */
+#endif /* HAVE_JUMP_LABEL */
+#endif /* __ASSEMBLY__ */
+
+#ifdef HAVE_JUMP_LABEL
+#include 
+#endif
+
+#ifndef __ASSEMBLY__
 
 enum jump_label_type {
JUMP_LABEL_DISABLE = 0,
@@ -203,3 +214,5 @@ static inline bool static_key_enabled(struct static_key 
*key)
 }
 
 #endif /* _LINUX_JUMP_LABEL_H */
+
+#endif /* __ASSEMBLY__ */
--
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Please read the FAQ at  http://www.tux.org/lkml/

[PATCH 2/3] jump_label: Allow jump labels to be used in assembly

[Anton Blanchard]

To use jump labels in assembly we need the HAVE_JUMP_LABEL define,
so we select a fallback version if the toolchain does not support
them.

Modify linux/jump_label.h so it can be included by assembly files.
We also need to add -DCC_HAVE_ASM_GOTO to KBUILD_AFLAGS.

Signed-off-by: Anton Blanchard 
---
 Makefile   |  1 +
 include/linux/jump_label.h | 21 +
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/Makefile b/Makefile
index e734965..3624215 100644
--- a/Makefile
+++ b/Makefile
@@ -779,6 +779,7 @@ KBUILD_ARFLAGS := $(call ar-option,D)
 # check for 'asm goto'
 ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC)), y)
KBUILD_CFLAGS += -DCC_HAVE_ASM_GOTO
+   KBUILD_AFLAGS += -DCC_HAVE_ASM_GOTO
 endif
 
 include $(srctree)/scripts/Makefile.kasan
diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index 98f923b6..f4de473 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -45,6 +45,12 @@
  * same as using STATIC_KEY_INIT_FALSE.
  */
 
+#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
+# define HAVE_JUMP_LABEL
+#endif
+
+#ifndef __ASSEMBLY__
+
 #include 
 #include 
 #include 
@@ -55,7 +61,7 @@ extern bool static_key_initialized;
"%s used before call to jump_label_init", \
__func__)
 
-#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
+#ifdef HAVE_JUMP_LABEL
 
 struct static_key {
atomic_t enabled;
@@ -66,13 +72,18 @@ struct static_key {
 #endif
 };
 
-# include 
-# define HAVE_JUMP_LABEL
 #else
 struct static_key {
atomic_t enabled;
 };
-#endif /* CC_HAVE_ASM_GOTO && CONFIG_JUMP_LABEL */
+#endif /* HAVE_JUMP_LABEL */
+#endif /* __ASSEMBLY__ */
+
+#ifdef HAVE_JUMP_LABEL
+#include 
+#endif
+
+#ifndef __ASSEMBLY__
 
 enum jump_label_type {
JUMP_LABEL_DISABLE = 0,
@@ -203,3 +214,5 @@ static inline bool static_key_enabled(struct static_key 
*key)
 }
 
 #endif /* _LINUX_JUMP_LABEL_H */
+
+#endif /* __ASSEMBLY__ */
-- 
2.1.0

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Please read the FAQ at  http://www.tux.org/lkml/

[PATCH 3/3] powerpc: Include linux/jump_label.h to get HAVE_JUMP_LABEL define

[Anton Blanchard]

Commit 1bc9e47aa8e4 ("powerpc/jump_label: Use HAVE_JUMP_LABEL")
converted uses of CONFIG_JUMP_LABEL to HAVE_JUMP_LABEL in
some assembly files.

HAVE_JUMP_LABEL is defined in linux/jump_label.h, so we need to
include this or we always get the non jump label fallback code.

Fixes: 1bc9e47aa8e4 ("powerpc/jump_label: Use HAVE_JUMP_LABEL")
Signed-off-by: Anton Blanchard 
---
 arch/powerpc/platforms/powernv/opal-wrappers.S | 2 +-
 arch/powerpc/platforms/pseries/hvCall.S| 2 +-
 arch/powerpc/platforms/pseries/lpar.c  | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S 
b/arch/powerpc/platforms/powernv/opal-wrappers.S
index b23fe7c..4c4fe6f 100644
--- a/arch/powerpc/platforms/powernv/opal-wrappers.S
+++ b/arch/powerpc/platforms/powernv/opal-wrappers.S
@@ -9,11 +9,11 @@
  * 2 of the License, or (at your option) any later version.
  */
 
+#include 
 #include 
 #include 
 #include 
 #include 
-#include 
 
.section".text"
 
diff --git a/arch/powerpc/platforms/pseries/hvCall.S 
b/arch/powerpc/platforms/pseries/hvCall.S
index ccd53f9..74b5b8e 100644
--- a/arch/powerpc/platforms/pseries/hvCall.S
+++ b/arch/powerpc/platforms/pseries/hvCall.S
@@ -7,12 +7,12 @@
  * as published by the Free Software Foundation; either version
  * 2 of the License, or (at your option) any later version.
  */
+#include 
 #include 
 #include 
 #include 
 #include 
 #include 
-#include 
 
.section".text"

diff --git a/arch/powerpc/platforms/pseries/lpar.c 
b/arch/powerpc/platforms/pseries/lpar.c
index b5682fd..b7a67e3 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -26,7 +26,7 @@
 #include 
 #include 
 #include 
-#include 
+#include 
 #include 
 #include 
 #include 
-- 
2.1.0

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[PATCH 1/3] jump_label: Allow asm/jump_label.h to be included in assembly

[Anton Blanchard]

Wrap asm/jump_label.h for all archs with #ifndef __ASSEMBLY__.
Since these are kernel only headers, we don't need #ifdef __KERNEL__
so can simplify things a bit.

If an architecture wants to use jump labels in assembly, it
will still need to define a macro to create the __jump_table
entries (see ARCH_STATIC_BRANCH in the powerpc asm/jump_label.h
for an example).

Signed-off-by: Anton Blanchard 
---
 arch/arm/include/asm/jump_label.h   | 5 ++---
 arch/arm64/include/asm/jump_label.h | 8 
 arch/mips/include/asm/jump_label.h  | 7 +++
 arch/s390/include/asm/jump_label.h  | 3 +++
 arch/sparc/include/asm/jump_label.h | 5 ++---
 arch/x86/include/asm/jump_label.h   | 5 ++---
 6 files changed, 16 insertions(+), 17 deletions(-)

diff --git a/arch/arm/include/asm/jump_label.h 
b/arch/arm/include/asm/jump_label.h
index 70f9b9b..5f337dc 100644
--- a/arch/arm/include/asm/jump_label.h
+++ b/arch/arm/include/asm/jump_label.h
@@ -1,7 +1,7 @@
 #ifndef _ASM_ARM_JUMP_LABEL_H
 #define _ASM_ARM_JUMP_LABEL_H
 
-#ifdef __KERNEL__
+#ifndef __ASSEMBLY__
 
 #include 
 
@@ -27,8 +27,6 @@ l_yes:
return true;
 }
 
-#endif /* __KERNEL__ */
-
 typedef u32 jump_label_t;
 
 struct jump_entry {
@@ -37,4 +35,5 @@ struct jump_entry {
jump_label_t key;
 };
 
+#endif  /* __ASSEMBLY__ */
 #endif
diff --git a/arch/arm64/include/asm/jump_label.h 
b/arch/arm64/include/asm/jump_label.h
index 076a1c7..c0e5165 100644
--- a/arch/arm64/include/asm/jump_label.h
+++ b/arch/arm64/include/asm/jump_label.h
@@ -18,11 +18,12 @@
  */
 #ifndef __ASM_JUMP_LABEL_H
 #define __ASM_JUMP_LABEL_H
+
+#ifndef __ASSEMBLY__
+
 #include 
 #include 
 
-#ifdef __KERNEL__
-
 #define JUMP_LABEL_NOP_SIZEAARCH64_INSN_SIZE
 
 static __always_inline bool arch_static_branch(struct static_key *key)
@@ -39,8 +40,6 @@ l_yes:
return true;
 }
 
-#endif /* __KERNEL__ */
-
 typedef u64 jump_label_t;
 
 struct jump_entry {
@@ -49,4 +48,5 @@ struct jump_entry {
jump_label_t key;
 };
 
+#endif  /* __ASSEMBLY__ */
 #endif /* __ASM_JUMP_LABEL_H */
diff --git a/arch/mips/include/asm/jump_label.h 
b/arch/mips/include/asm/jump_label.h
index fdbff44..608aa57 100644
--- a/arch/mips/include/asm/jump_label.h
+++ b/arch/mips/include/asm/jump_label.h
@@ -8,9 +8,9 @@
 #ifndef _ASM_MIPS_JUMP_LABEL_H
 #define _ASM_MIPS_JUMP_LABEL_H
 
-#include 
+#ifndef __ASSEMBLY__
 
-#ifdef __KERNEL__
+#include 
 
 #define JUMP_LABEL_NOP_SIZE 4
 
@@ -39,8 +39,6 @@ l_yes:
return true;
 }
 
-#endif /* __KERNEL__ */
-
 #ifdef CONFIG_64BIT
 typedef u64 jump_label_t;
 #else
@@ -53,4 +51,5 @@ struct jump_entry {
jump_label_t key;
 };
 
+#endif  /* __ASSEMBLY__ */
 #endif /* _ASM_MIPS_JUMP_LABEL_H */
diff --git a/arch/s390/include/asm/jump_label.h 
b/arch/s390/include/asm/jump_label.h
index 58642fd..2b77e23 100644
--- a/arch/s390/include/asm/jump_label.h
+++ b/arch/s390/include/asm/jump_label.h
@@ -1,6 +1,8 @@
 #ifndef _ASM_S390_JUMP_LABEL_H
 #define _ASM_S390_JUMP_LABEL_H
 
+#ifndef __ASSEMBLY__
+
 #include 
 
 #define JUMP_LABEL_NOP_SIZE 6
@@ -39,4 +41,5 @@ struct jump_entry {
jump_label_t key;
 };
 
+#endif  /* __ASSEMBLY__ */
 #endif
diff --git a/arch/sparc/include/asm/jump_label.h 
b/arch/sparc/include/asm/jump_label.h
index ec2e2e2..cc9b04a 100644
--- a/arch/sparc/include/asm/jump_label.h
+++ b/arch/sparc/include/asm/jump_label.h
@@ -1,7 +1,7 @@
 #ifndef _ASM_SPARC_JUMP_LABEL_H
 #define _ASM_SPARC_JUMP_LABEL_H
 
-#ifdef __KERNEL__
+#ifndef __ASSEMBLY__
 
 #include 
 
@@ -22,8 +22,6 @@ l_yes:
return true;
 }
 
-#endif /* __KERNEL__ */
-
 typedef u32 jump_label_t;
 
 struct jump_entry {
@@ -32,4 +30,5 @@ struct jump_entry {
jump_label_t key;
 };
 
+#endif  /* __ASSEMBLY__ */
 #endif
diff --git a/arch/x86/include/asm/jump_label.h 
b/arch/x86/include/asm/jump_label.h
index 6a2cefb..a4c1cf7 100644
--- a/arch/x86/include/asm/jump_label.h
+++ b/arch/x86/include/asm/jump_label.h
@@ -1,7 +1,7 @@
 #ifndef _ASM_X86_JUMP_LABEL_H
 #define _ASM_X86_JUMP_LABEL_H
 
-#ifdef __KERNEL__
+#ifndef __ASSEMBLY__
 
 #include 
 #include 
@@ -30,8 +30,6 @@ l_yes:
return true;
 }
 
-#endif /* __KERNEL__ */
-
 #ifdef CONFIG_X86_64
 typedef u64 jump_label_t;
 #else
@@ -44,4 +42,5 @@ struct jump_entry {
jump_label_t key;
 };
 
+#endif  /* __ASSEMBLY__ */
 #endif
-- 
2.1.0

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[PATCH 4/7] x86: Use die_spin_lock_{irqsave,irqrestore}

[Anton Blanchard]

Replace the x86 specific oops locking with the common one.

Signed-off-by: Anton Blanchard 
---
 arch/x86/kernel/dumpstack.c | 26 +++---
 1 file changed, 3 insertions(+), 23 deletions(-)

diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index b74ebc7..b635f73 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -15,6 +15,7 @@
 #include 
 #include 
 #include 
+#include 
 
 #include 
 
@@ -196,28 +197,12 @@ void show_stack(struct task_struct *task, unsigned long 
*sp)
show_stack_log_lvl(task, NULL, sp, bp, "");
 }
 
-static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
-static int die_owner = -1;
-static unsigned int die_nest_count;
-
 unsigned long oops_begin(void)
 {
-   int cpu;
unsigned long flags;
 
oops_enter();
-
-   /* racy, but better than risking deadlock. */
-   raw_local_irq_save(flags);
-   cpu = smp_processor_id();
-   if (!arch_spin_trylock(&die_lock)) {
-   if (cpu == die_owner)
-   /* nested oops. should stop eventually */;
-   else
-   arch_spin_lock(&die_lock);
-   }
-   die_nest_count++;
-   die_owner = cpu;
+   die_spin_lock_irqsave(flags);
console_verbose();
bust_spinlocks(1);
return flags;
@@ -231,13 +216,8 @@ void oops_end(unsigned long flags, struct pt_regs *regs, 
int signr)
crash_kexec(regs);
 
bust_spinlocks(0);
-   die_owner = -1;
add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
-   die_nest_count--;
-   if (!die_nest_count)
-   /* Nest count reaches zero, release the lock. */
-   arch_spin_unlock(&die_lock);
-   raw_local_irq_restore(flags);
+   die_spin_unlock_irqrestore(flags);
oops_exit();
 
if (!signr)
-- 
2.1.0

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[PATCH 2/7] powerpc: Use die_spin_lock_{irqsave,irqrestore}

[Anton Blanchard]

Replace the powerpc specific oops locking with the common one.

Signed-off-by: Anton Blanchard 
---
 arch/powerpc/kernel/traps.c | 24 +++-
 1 file changed, 3 insertions(+), 21 deletions(-)

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 19e4744..4cc1e72 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -36,6 +36,7 @@
 #include 
 #include 
 #include 
+#include 
 
 #include 
 #include 
@@ -109,14 +110,10 @@ static void pmac_backlight_unblank(void)
 static inline void pmac_backlight_unblank(void) { }
 #endif
 
-static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
-static int die_owner = -1;
-static unsigned int die_nest_count;
 static int die_counter;
 
 static unsigned __kprobes long oops_begin(struct pt_regs *regs)
 {
-   int cpu;
unsigned long flags;
 
if (debugger(regs))
@@ -124,17 +121,7 @@ static unsigned __kprobes long oops_begin(struct pt_regs 
*regs)
 
oops_enter();
 
-   /* racy, but better than risking deadlock. */
-   raw_local_irq_save(flags);
-   cpu = smp_processor_id();
-   if (!arch_spin_trylock(&die_lock)) {
-   if (cpu == die_owner)
-   /* nested oops. should stop eventually */;
-   else
-   arch_spin_lock(&die_lock);
-   }
-   die_nest_count++;
-   die_owner = cpu;
+   die_spin_lock_irqsave(flags);
console_verbose();
bust_spinlocks(1);
if (machine_is(powermac))
@@ -146,15 +133,10 @@ static void __kprobes oops_end(unsigned long flags, 
struct pt_regs *regs,
   int signr)
 {
bust_spinlocks(0);
-   die_owner = -1;
add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
-   die_nest_count--;
oops_exit();
printk("\n");
-   if (!die_nest_count)
-   /* Nest count reaches zero, release the lock. */
-   arch_spin_unlock(&die_lock);
-   raw_local_irq_restore(flags);
+   die_spin_unlock_irqrestore(flags);
 
crash_fadump(regs, "die oops");
 
-- 
2.1.0

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[PATCH 5/7] watchdog: Serialise soft lockup errors with die_spin_lock_{irqsave,irqrestore}

[Anton Blanchard]

A simple kernel module was used to create concurrent soft and
hard lockups:

http://ozlabs.org/~anton/junkcode/badguy.tar.gz

Signed-off-by: Anton Blanchard 
---
 kernel/watchdog.c | 4 
 1 file changed, 4 insertions(+)

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 70bf118..dd161e3 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -19,6 +19,7 @@
 #include 
 #include 
 #include 
+#include 
 
 #include 
 #include 
@@ -313,6 +314,7 @@ static enum hrtimer_restart watchdog_timer_fn(struct 
hrtimer *hrtimer)
struct pt_regs *regs = get_irq_regs();
int duration;
int softlockup_all_cpu_backtrace = sysctl_softlockup_all_cpu_backtrace;
+   unsigned long flags;
 
/* kick the hardlockup detector */
watchdog_interrupt_count();
@@ -384,6 +386,7 @@ static enum hrtimer_restart watchdog_timer_fn(struct 
hrtimer *hrtimer)
}
}
 
+   die_spin_lock_irqsave(flags);
pr_emerg("BUG: soft lockup - CPU#%d stuck for %us! [%s:%d]\n",
smp_processor_id(), duration,
current->comm, task_pid_nr(current));
@@ -394,6 +397,7 @@ static enum hrtimer_restart watchdog_timer_fn(struct 
hrtimer *hrtimer)
show_regs(regs);
else
dump_stack();
+   die_spin_unlock_irqrestore(flags);
 
if (softlockup_all_cpu_backtrace) {
/* Avoid generating two back traces for current
-- 
2.1.0

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[PATCH 7/7] powerpc: Serialise BUG and WARNs with die_spin_lock_{irqsave,irqrestore}

[Anton Blanchard]

A simple kernel module was used to create concurrent WARNs and BUGs:

http://ozlabs.org/~anton/junkcode/warnstorm.tar.gz

Signed-off-by: Anton Blanchard 
---
 arch/powerpc/kernel/traps.c | 44 
 1 file changed, 36 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 4cc1e72..f779557 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -1114,6 +1114,39 @@ static int emulate_math(struct pt_regs *regs)
 static inline int emulate_math(struct pt_regs *regs) { return -1; }
 #endif
 
+static bool __report_bug(unsigned long bugaddr, struct pt_regs *regs)
+{
+   const struct bug_entry *bug;
+   unsigned long flags;
+   int err;
+
+   if (!is_valid_bugaddr(bugaddr))
+   return false;
+
+   bug = find_bug(bugaddr);
+   if (!bug)
+   return false;
+
+   if (is_warning_bug(bug)) {
+   die_spin_lock_irqsave(flags);
+   report_bug(bugaddr, regs);
+   die_spin_unlock_irqrestore(flags);
+
+   regs->nip += 4;
+
+   return true;
+   }
+
+   flags = oops_begin(regs);
+   report_bug(bugaddr, regs);
+   err = SIGTRAP;
+   if (__die("Exception in kernel mode", regs, err))
+   err = 0;
+   oops_end(flags, regs, err);
+
+   return true;
+}
+
 void __kprobes program_check_exception(struct pt_regs *regs)
 {
enum ctx_state prev_state = exception_enter();
@@ -1138,11 +1171,9 @@ void __kprobes program_check_exception(struct pt_regs 
*regs)
== NOTIFY_STOP)
goto bail;
 
-   if (!(regs->msr & MSR_PR) &&  /* not user-mode */
-   report_bug(regs->nip, regs) == BUG_TRAP_TYPE_WARN) {
-   regs->nip += 4;
+   if (!user_mode(regs) && __report_bug(regs->nip, regs))
goto bail;
-   }
+
_exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
goto bail;
}
@@ -1157,11 +1188,8 @@ void __kprobes program_check_exception(struct pt_regs 
*regs)
 * -  A tend is illegally attempted.
 * -  writing a TM SPR when transactional.
 */
-   if (!user_mode(regs) &&
-   report_bug(regs->nip, regs) == BUG_TRAP_TYPE_WARN) {
-   regs->nip += 4;
+   if (!user_mode(regs) && __report_bug(regs->nip, regs))
goto bail;
-   }
/* If usermode caused this, it's done something illegal and
 * gets a SIGILL slap on the wrist.  We call it an illegal
 * operand to distinguish from the instruction just being bad
-- 
2.1.0

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[PATCH 6/7] dump_stack: Serialise dump_stack with die_spin_lock_{irqsave,irqrestore}

[Anton Blanchard]

Remove another version of a recursive lock in dump_stack.

Signed-off-by: Anton Blanchard 
---
 lib/dump_stack.c | 40 
 1 file changed, 4 insertions(+), 36 deletions(-)

diff --git a/lib/dump_stack.c b/lib/dump_stack.c
index 6745c62..f64ee3c 100644
--- a/lib/dump_stack.c
+++ b/lib/dump_stack.c
@@ -7,7 +7,7 @@
 #include 
 #include 
 #include 
-#include 
+#include 
 
 static void __dump_stack(void)
 {
@@ -20,44 +20,12 @@ static void __dump_stack(void)
  *
  * Architectures can override this implementation by implementing its own.
  */
-#ifdef CONFIG_SMP
-static atomic_t dump_lock = ATOMIC_INIT(-1);
-
 asmlinkage __visible void dump_stack(void)
 {
-   int was_locked;
-   int old;
-   int cpu;
-
-   /*
-* Permit this cpu to perform nested stack dumps while serialising
-* against other CPUs
-*/
-   preempt_disable();
-
-retry:
-   cpu = smp_processor_id();
-   old = atomic_cmpxchg(&dump_lock, -1, cpu);
-   if (old == -1) {
-   was_locked = 0;
-   } else if (old == cpu) {
-   was_locked = 1;
-   } else {
-   cpu_relax();
-   goto retry;
-   }
-
-   __dump_stack();
+   unsigned long flags;
 
-   if (!was_locked)
-   atomic_set(&dump_lock, -1);
-
-   preempt_enable();
-}
-#else
-asmlinkage __visible void dump_stack(void)
-{
+   die_spin_lock_irqsave(flags);
__dump_stack();
+   die_spin_unlock_irqrestore(flags);
 }
-#endif
 EXPORT_SYMBOL(dump_stack);
-- 
2.1.0

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[PATCH 1/7] Add die_spin_lock_{irqsave,irqrestore}

[Anton Blanchard]

Many architectures have their own oops locking code that allows
the lock to be taken recursively. Create a common version.

Avoid creating generic locking functions, so they can't be
abused in other parts of the kernel.

Signed-off-by: Anton Blanchard 
---
 include/linux/die_lock.h | 23 +++
 lib/Makefile |  1 +
 lib/die_lock.c   | 43 +++
 3 files changed, 67 insertions(+)
 create mode 100644 include/linux/die_lock.h
 create mode 100644 lib/die_lock.c

diff --git a/include/linux/die_lock.h b/include/linux/die_lock.h
new file mode 100644
index 000..540d09d
--- /dev/null
+++ b/include/linux/die_lock.h
@@ -0,0 +1,23 @@
+#ifndef __LINUX_DIE_LOCK_H
+#define __LINUX_DIE_LOCK_H
+
+#include 
+
+/**
+ * die_spin_lock_irqsave - lock die spinlock
+ * @flags: interrupt state is saved here
+ *
+ * The die spinlock is used to serialise output during oopses, BUGs and
+ * WARNs. It can be taken recursively so that nested oopses will not
+ * lock up.
+ */
+unsigned long __die_spin_lock_irqsave(void);
+#define die_spin_lock_irqsave(flags)   \
+   do {\
+   typecheck(unsigned long, flags);\
+   flags = __die_spin_lock_irqsave();  \
+   } while (0)
+
+void die_spin_unlock_irqrestore(unsigned long flags);
+
+#endif /* __LINUX_DIE_LOCK_H */
diff --git a/lib/Makefile b/lib/Makefile
index 3c3b30b..7d87a80 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -28,6 +28,7 @@ obj-y += bcd.o div64.o sort.o parser.o halfmd4.o 
debug_locks.o random32.o \
 bsearch.o find_last_bit.o find_next_bit.o llist.o memweight.o kfifo.o \
 percpu-refcount.o percpu_ida.o rhashtable.o reciprocal_div.o
 obj-y += string_helpers.o
+obj-y += die_lock.o
 obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o
 obj-y += kstrtox.o
 obj-$(CONFIG_TEST_KSTRTOX) += test-kstrtox.o
diff --git a/lib/die_lock.c b/lib/die_lock.c
new file mode 100644
index 000..5d2de2e
--- /dev/null
+++ b/lib/die_lock.c
@@ -0,0 +1,43 @@
+#include 
+#include 
+
+static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
+static int die_owner = -1;
+static unsigned int die_nest_count;
+
+unsigned long __die_spin_lock_irqsave(void)
+{
+   unsigned long flags;
+   int cpu;
+
+   /* racy, but better than risking deadlock. */
+   raw_local_irq_save(flags);
+
+   cpu = smp_processor_id();
+   if (!arch_spin_trylock(&die_lock)) {
+   if (cpu != die_owner)
+   arch_spin_lock(&die_lock);
+   }
+   die_nest_count++;
+   die_owner = cpu;
+
+   return flags;
+}
+
+/**
+ * die_spin_unlock_irqrestore - Unlock die spinlock
+ * @flags: interrupt state to restore
+ *
+ * Unlock die spinlock and restore interrupt state. This must be
+ * paired with die_spin_lock_irqsave.
+ */
+void die_spin_unlock_irqrestore(unsigned long flags)
+{
+   die_nest_count--;
+   if (!die_nest_count) {
+   die_owner = -1;
+   /* Nest count reaches zero, release the lock. */
+   arch_spin_unlock(&die_lock);
+   }
+   raw_local_irq_restore(flags);
+}
-- 
2.1.0

--
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[PATCH 0/7] Serialise oopses, BUGs, WARNs, dump_stack, soft lockups and hard lockups

[Anton Blanchard]

Every now and then I end up with an undebuggable issue because multiple
CPUs hit something at the same time and everything is interleaved:

CR: 4882  XER: 
,RI
c003dc72fd10
,LE
d65b84e8
Instruction dump:
MSR: 800100029033

Very annoying.

Some architectures already have their own recursive locking for oopses
and we have another version for serialising dump_stack.

Create a common version and use it everywhere (oopses, BUGs, WARNs,
dump_stack, soft lockups and hard lockups). A few testcases were
used to verify the series:

A trivial module to create concurrent WARNs, BUGs and oopses:

http://ozlabs.org/~anton/junkcode/warnstorm.tar.gz

And one to create concurrent soft and hard lockups:

http://ozlabs.org/~anton/junkcode/badguy.tar.gz

Anton Blanchard (7):
  Add die_spin_lock_{irqsave,irqrestore}
  powerpc: Use die_spin_lock_{irqsave,irqrestore}
  arm: Use die_spin_lock_{irqsave,irqrestore}
  x86: Use die_spin_lock_{irqsave,irqrestore}
  watchdog: Serialise soft lockup errors with
die_spin_lock_{irqsave,irqrestore}
  dump_stack: Serialise dump_stack with
die_spin_lock_{irqsave,irqrestore}
  powerpc: Serialise BUG and WARNs with
die_spin_lock_{irqsave,irqrestore}

 arch/arm/kernel/traps.c | 26 ++---
 arch/powerpc/kernel/traps.c | 68 ++---
 arch/x86/kernel/dumpstack.c | 26 ++---
 include/linux/die_lock.h| 23 +++
 kernel/watchdog.c   |  4 +++
 lib/Makefile|  1 +
 lib/die_lock.c  | 43 
 lib/dump_stack.c| 40 +++---
 8 files changed, 120 insertions(+), 111 deletions(-)
 create mode 100644 include/linux/die_lock.h
 create mode 100644 lib/die_lock.c

-- 
2.1.0

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[PATCH 3/7] arm: Use die_spin_lock_{irqsave,irqrestore}

[Anton Blanchard]

Replace the ARM specific oops locking with the common one.

Signed-off-by: Anton Blanchard 
---
 arch/arm/kernel/traps.c | 26 +++---
 1 file changed, 3 insertions(+), 23 deletions(-)

diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 788e23f..3e3469d 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -26,6 +26,7 @@
 #include 
 #include 
 #include 
+#include 
 
 #include 
 #include 
@@ -263,28 +264,12 @@ static int __die(const char *str, int err, struct pt_regs 
*regs)
return 0;
 }
 
-static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
-static int die_owner = -1;
-static unsigned int die_nest_count;
-
 static unsigned long oops_begin(void)
 {
-   int cpu;
unsigned long flags;
 
oops_enter();
-
-   /* racy, but better than risking deadlock. */
-   raw_local_irq_save(flags);
-   cpu = smp_processor_id();
-   if (!arch_spin_trylock(&die_lock)) {
-   if (cpu == die_owner)
-   /* nested oops. should stop eventually */;
-   else
-   arch_spin_lock(&die_lock);
-   }
-   die_nest_count++;
-   die_owner = cpu;
+   die_spin_lock_irqsave(flags);
console_verbose();
bust_spinlocks(1);
return flags;
@@ -296,13 +281,8 @@ static void oops_end(unsigned long flags, struct pt_regs 
*regs, int signr)
crash_kexec(regs);
 
bust_spinlocks(0);
-   die_owner = -1;
add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
-   die_nest_count--;
-   if (!die_nest_count)
-   /* Nest count reaches zero, release the lock. */
-   arch_spin_unlock(&die_lock);
-   raw_local_irq_restore(flags);
+   die_spin_unlock_irqrestore(flags);
oops_exit();
 
if (in_interrupt())
-- 
2.1.0

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Re: [PATCH 3/3] powerpc: Include linux/jump_label.h to get HAVE_JUMP_LABEL define

[Anton Blanchard]

Hi Jason,

> > diff --git a/arch/powerpc/platforms/pseries/lpar.c
> > b/arch/powerpc/platforms/pseries/lpar.c index 469751d..14ac1ad
> > 100644 --- a/arch/powerpc/platforms/pseries/lpar.c
> > +++ b/arch/powerpc/platforms/pseries/lpar.c
> > @@ -27,6 +27,7 @@
> >  #include 
> >  #include 
> >  #include 
> > +#include 
> >  #include 
> >  #include 
> >  #include 
> 
> You can drop the 'static_key.h' include here since its redundant.

Thanks, I incorporated this into the next series.

Anton
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Re: Confusing behaviour with /proc/sys/kernel/nmi_watchdog

[Anton Blanchard]

Hi Andrew,

> On Wed, Nov 05, 2014 at 09:34:20AM +1100, Anton Blanchard wrote:
> > commit 9919e39a1738 ("kvm: ensure hard lockup detection is disabled
> > by default") provided a way for the kernel to disable the hard
> > lockup detector at runtime.
> > 
> > I'm using it on ppc64 but notice some weird behaviour with the
> > nmi_watchdog procfs variable. At boot, that the hard lockup
> > detector appears to be enabled even when we disable it via
> > watchdog_enable_hardlockup_detector(false):
> > 
> > # cat /proc/sys/kernel/nmi_watchdog 
> > 1
> > 
> > I have to echo 0 to it then echo 1 again to enable it.
> > 
> > Anton
> 
> Hi Anton,
> 
> Yes, the nmi watchdog proc variables are currently a bit
> confusing. Uli has posted a series to clear all that up
> though. Please see
> 
> https://lkml.org/lkml/2014/10/17/340

Any progress on this? I'm rebasing our hardware NMI patch for ppc64 and
notice the strange behaviour is still in mainline.

Anton
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[PATCH 2/3] jump_label: Allow jump labels to be used in assembly

[Anton Blanchard]

To use jump labels in assembly we need the HAVE_JUMP_LABEL define,
so we select a fallback version if the toolchain does not support
them.

Modify linux/jump_label.h so it can be included by assembly files.
We also need to add -DCC_HAVE_ASM_GOTO to KBUILD_AFLAGS.

Signed-off-by: Anton Blanchard 
---
 Makefile   |  1 +
 include/linux/jump_label.h | 21 +
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/Makefile b/Makefile
index ef748e1..7b83c3f 100644
--- a/Makefile
+++ b/Makefile
@@ -774,6 +774,7 @@ KBUILD_ARFLAGS := $(call ar-option,D)
 # check for 'asm goto'
 ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC)), y)
KBUILD_CFLAGS += -DCC_HAVE_ASM_GOTO
+   KBUILD_AFLAGS += -DCC_HAVE_ASM_GOTO
 endif
 
 include $(srctree)/scripts/Makefile.extrawarn
diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index 98f923b6..f4de473 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -45,6 +45,12 @@
  * same as using STATIC_KEY_INIT_FALSE.
  */
 
+#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
+# define HAVE_JUMP_LABEL
+#endif
+
+#ifndef __ASSEMBLY__
+
 #include 
 #include 
 #include 
@@ -55,7 +61,7 @@ extern bool static_key_initialized;
"%s used before call to jump_label_init", \
__func__)
 
-#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
+#ifdef HAVE_JUMP_LABEL
 
 struct static_key {
atomic_t enabled;
@@ -66,13 +72,18 @@ struct static_key {
 #endif
 };
 
-# include 
-# define HAVE_JUMP_LABEL
 #else
 struct static_key {
atomic_t enabled;
 };
-#endif /* CC_HAVE_ASM_GOTO && CONFIG_JUMP_LABEL */
+#endif /* HAVE_JUMP_LABEL */
+#endif /* __ASSEMBLY__ */
+
+#ifdef HAVE_JUMP_LABEL
+#include 
+#endif
+
+#ifndef __ASSEMBLY__
 
 enum jump_label_type {
JUMP_LABEL_DISABLE = 0,
@@ -203,3 +214,5 @@ static inline bool static_key_enabled(struct static_key 
*key)
 }
 
 #endif /* _LINUX_JUMP_LABEL_H */
+
+#endif /* __ASSEMBLY__ */
-- 
2.1.0

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[PATCH 1/3] jump_label: Allow asm/jump_label.h to be included in assembly

[Anton Blanchard]

Wrap asm/jump_label.h for all archs with #ifndef __ASSEMBLY__.
Since these are kernel only headers, we don't need #ifdef __KERNEL__
so can simplify things a bit.

If an architecture wants to use jump labels in assembly, it
will still need to define a macro to create the __jump_table
entries (see ARCH_STATIC_BRANCH in the powerpc asm/jump_label.h
for an example).

Signed-off-by: Anton Blanchard 
---
 arch/arm/include/asm/jump_label.h   | 5 ++---
 arch/arm64/include/asm/jump_label.h | 8 
 arch/mips/include/asm/jump_label.h  | 7 +++
 arch/s390/include/asm/jump_label.h  | 3 +++
 arch/sparc/include/asm/jump_label.h | 5 ++---
 arch/x86/include/asm/jump_label.h   | 5 ++---
 6 files changed, 16 insertions(+), 17 deletions(-)

diff --git a/arch/arm/include/asm/jump_label.h 
b/arch/arm/include/asm/jump_label.h
index 70f9b9b..5f337dc 100644
--- a/arch/arm/include/asm/jump_label.h
+++ b/arch/arm/include/asm/jump_label.h
@@ -1,7 +1,7 @@
 #ifndef _ASM_ARM_JUMP_LABEL_H
 #define _ASM_ARM_JUMP_LABEL_H
 
-#ifdef __KERNEL__
+#ifndef __ASSEMBLY__
 
 #include 
 
@@ -27,8 +27,6 @@ l_yes:
return true;
 }
 
-#endif /* __KERNEL__ */
-
 typedef u32 jump_label_t;
 
 struct jump_entry {
@@ -37,4 +35,5 @@ struct jump_entry {
jump_label_t key;
 };
 
+#endif  /* __ASSEMBLY__ */
 #endif
diff --git a/arch/arm64/include/asm/jump_label.h 
b/arch/arm64/include/asm/jump_label.h
index 076a1c7..c0e5165 100644
--- a/arch/arm64/include/asm/jump_label.h
+++ b/arch/arm64/include/asm/jump_label.h
@@ -18,11 +18,12 @@
  */
 #ifndef __ASM_JUMP_LABEL_H
 #define __ASM_JUMP_LABEL_H
+
+#ifndef __ASSEMBLY__
+
 #include 
 #include 
 
-#ifdef __KERNEL__
-
 #define JUMP_LABEL_NOP_SIZEAARCH64_INSN_SIZE
 
 static __always_inline bool arch_static_branch(struct static_key *key)
@@ -39,8 +40,6 @@ l_yes:
return true;
 }
 
-#endif /* __KERNEL__ */
-
 typedef u64 jump_label_t;
 
 struct jump_entry {
@@ -49,4 +48,5 @@ struct jump_entry {
jump_label_t key;
 };
 
+#endif  /* __ASSEMBLY__ */
 #endif /* __ASM_JUMP_LABEL_H */
diff --git a/arch/mips/include/asm/jump_label.h 
b/arch/mips/include/asm/jump_label.h
index fdbff44..608aa57 100644
--- a/arch/mips/include/asm/jump_label.h
+++ b/arch/mips/include/asm/jump_label.h
@@ -8,9 +8,9 @@
 #ifndef _ASM_MIPS_JUMP_LABEL_H
 #define _ASM_MIPS_JUMP_LABEL_H
 
-#include 
+#ifndef __ASSEMBLY__
 
-#ifdef __KERNEL__
+#include 
 
 #define JUMP_LABEL_NOP_SIZE 4
 
@@ -39,8 +39,6 @@ l_yes:
return true;
 }
 
-#endif /* __KERNEL__ */
-
 #ifdef CONFIG_64BIT
 typedef u64 jump_label_t;
 #else
@@ -53,4 +51,5 @@ struct jump_entry {
jump_label_t key;
 };
 
+#endif  /* __ASSEMBLY__ */
 #endif /* _ASM_MIPS_JUMP_LABEL_H */
diff --git a/arch/s390/include/asm/jump_label.h 
b/arch/s390/include/asm/jump_label.h
index 346b1c8..1e78ffd 100644
--- a/arch/s390/include/asm/jump_label.h
+++ b/arch/s390/include/asm/jump_label.h
@@ -1,6 +1,8 @@
 #ifndef _ASM_S390_JUMP_LABEL_H
 #define _ASM_S390_JUMP_LABEL_H
 
+#ifndef __ASSEMBLY__
+
 #include 
 
 #define JUMP_LABEL_NOP_SIZE 6
@@ -34,4 +36,5 @@ struct jump_entry {
jump_label_t key;
 };
 
+#endif  /* __ASSEMBLY__ */
 #endif
diff --git a/arch/sparc/include/asm/jump_label.h 
b/arch/sparc/include/asm/jump_label.h
index ec2e2e2..cc9b04a 100644
--- a/arch/sparc/include/asm/jump_label.h
+++ b/arch/sparc/include/asm/jump_label.h
@@ -1,7 +1,7 @@
 #ifndef _ASM_SPARC_JUMP_LABEL_H
 #define _ASM_SPARC_JUMP_LABEL_H
 
-#ifdef __KERNEL__
+#ifndef __ASSEMBLY__
 
 #include 
 
@@ -22,8 +22,6 @@ l_yes:
return true;
 }
 
-#endif /* __KERNEL__ */
-
 typedef u32 jump_label_t;
 
 struct jump_entry {
@@ -32,4 +30,5 @@ struct jump_entry {
jump_label_t key;
 };
 
+#endif  /* __ASSEMBLY__ */
 #endif
diff --git a/arch/x86/include/asm/jump_label.h 
b/arch/x86/include/asm/jump_label.h
index 6a2cefb..a4c1cf7 100644
--- a/arch/x86/include/asm/jump_label.h
+++ b/arch/x86/include/asm/jump_label.h
@@ -1,7 +1,7 @@
 #ifndef _ASM_X86_JUMP_LABEL_H
 #define _ASM_X86_JUMP_LABEL_H
 
-#ifdef __KERNEL__
+#ifndef __ASSEMBLY__
 
 #include 
 #include 
@@ -30,8 +30,6 @@ l_yes:
return true;
 }
 
-#endif /* __KERNEL__ */
-
 #ifdef CONFIG_X86_64
 typedef u64 jump_label_t;
 #else
@@ -44,4 +42,5 @@ struct jump_entry {
jump_label_t key;
 };
 
+#endif  /* __ASSEMBLY__ */
 #endif
-- 
2.1.0

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[PATCH 3/3] powerpc: Include linux/jump_label.h to get HAVE_JUMP_LABEL define

[Anton Blanchard]

Commit 1bc9e47aa8e4 ("powerpc/jump_label: Use HAVE_JUMP_LABEL")
converted uses of CONFIG_JUMP_LABEL to HAVE_JUMP_LABEL in
some assembly files.

HAVE_JUMP_LABEL is defined in linux/jump_label.h, so we need to
include this or we always get the non jump label fallback code.

Fixes: 1bc9e47aa8e4 ("powerpc/jump_label: Use HAVE_JUMP_LABEL")
Signed-off-by: Anton Blanchard 
---
 arch/powerpc/platforms/powernv/opal-wrappers.S | 2 +-
 arch/powerpc/platforms/pseries/hvCall.S| 2 +-
 arch/powerpc/platforms/pseries/lpar.c  | 1 +
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S 
b/arch/powerpc/platforms/powernv/opal-wrappers.S
index 0509bca..fcbe899 100644
--- a/arch/powerpc/platforms/powernv/opal-wrappers.S
+++ b/arch/powerpc/platforms/powernv/opal-wrappers.S
@@ -9,11 +9,11 @@
  * 2 of the License, or (at your option) any later version.
  */
 
+#include 
 #include 
 #include 
 #include 
 #include 
-#include 
 
.section".text"
 
diff --git a/arch/powerpc/platforms/pseries/hvCall.S 
b/arch/powerpc/platforms/pseries/hvCall.S
index ccd53f9..74b5b8e 100644
--- a/arch/powerpc/platforms/pseries/hvCall.S
+++ b/arch/powerpc/platforms/pseries/hvCall.S
@@ -7,12 +7,12 @@
  * as published by the Free Software Foundation; either version
  * 2 of the License, or (at your option) any later version.
  */
+#include 
 #include 
 #include 
 #include 
 #include 
 #include 
-#include 
 
.section".text"

diff --git a/arch/powerpc/platforms/pseries/lpar.c 
b/arch/powerpc/platforms/pseries/lpar.c
index 469751d..14ac1ad 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -27,6 +27,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 #include 
 #include 
-- 
2.1.0

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Re: [PATCH 1/2] jump_label: Allow jump labels to be used in assembly

[Anton Blanchard]

Hi Steve,

> Have you tested this on other archs? Because just looking at x86, it
> doesn't seem that asm/jump_label.h can handle being called in
> assembly.

Since no one is including linux/jump_label.h in assembly yet, nothing
should break. We could however add __ASSEMBLY__ protection to all the
asm/jump_label.h files. Patches on the way.

Anton
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[PATCH 2/2] powerpc: Include linux/jump_label.h to get HAVE_JUMP_LABEL define

[Anton Blanchard]

Commit 1bc9e47aa8e4 ("powerpc/jump_label: Use HAVE_JUMP_LABEL")
converted uses of CONFIG_JUMP_LABEL to HAVE_JUMP_LABEL in
some assembly files.

HAVE_JUMP_LABEL is defined in linux/jump_label.h, so we need to
include this or we always get the non jump label fallback code.

Fixes: 1bc9e47aa8e4 ("powerpc/jump_label: Use HAVE_JUMP_LABEL")
Signed-off-by: Anton Blanchard 
---
 arch/powerpc/platforms/pseries/hvCall.S | 2 +-
 arch/powerpc/platforms/pseries/lpar.c   | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/pseries/hvCall.S 
b/arch/powerpc/platforms/pseries/hvCall.S
index ccd53f9..74b5b8e 100644
--- a/arch/powerpc/platforms/pseries/hvCall.S
+++ b/arch/powerpc/platforms/pseries/hvCall.S
@@ -7,12 +7,12 @@
  * as published by the Free Software Foundation; either version
  * 2 of the License, or (at your option) any later version.
  */
+#include 
 #include 
 #include 
 #include 
 #include 
 #include 
-#include 
 
.section".text"

diff --git a/arch/powerpc/platforms/pseries/lpar.c 
b/arch/powerpc/platforms/pseries/lpar.c
index 469751d..14ac1ad 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -27,6 +27,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 #include 
 #include 
-- 
2.1.0

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[PATCH 1/2] jump_label: Allow jump labels to be used in assembly

[Anton Blanchard]

To use jump labels in assembly we need the HAVE_JUMP_LABEL define,
so we select a fallback version if the toolchain does not support
them.

Modify linux/jump_label.h so it can be included by assembly files.
We also need to add -DCC_HAVE_ASM_GOTO to KBUILD_AFLAGS.

Signed-off-by: Anton Blanchard 
---
 Makefile   |  1 +
 include/linux/jump_label.h | 21 +
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/Makefile b/Makefile
index ef748e1..7b83c3f 100644
--- a/Makefile
+++ b/Makefile
@@ -774,6 +774,7 @@ KBUILD_ARFLAGS := $(call ar-option,D)
 # check for 'asm goto'
 ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC)), y)
KBUILD_CFLAGS += -DCC_HAVE_ASM_GOTO
+   KBUILD_AFLAGS += -DCC_HAVE_ASM_GOTO
 endif
 
 include $(srctree)/scripts/Makefile.extrawarn
diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index 98f923b6..f4de473 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -45,6 +45,12 @@
  * same as using STATIC_KEY_INIT_FALSE.
  */
 
+#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
+# define HAVE_JUMP_LABEL
+#endif
+
+#ifndef __ASSEMBLY__
+
 #include 
 #include 
 #include 
@@ -55,7 +61,7 @@ extern bool static_key_initialized;
"%s used before call to jump_label_init", \
__func__)
 
-#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
+#ifdef HAVE_JUMP_LABEL
 
 struct static_key {
atomic_t enabled;
@@ -66,13 +72,18 @@ struct static_key {
 #endif
 };
 
-# include 
-# define HAVE_JUMP_LABEL
 #else
 struct static_key {
atomic_t enabled;
 };
-#endif /* CC_HAVE_ASM_GOTO && CONFIG_JUMP_LABEL */
+#endif /* HAVE_JUMP_LABEL */
+#endif /* __ASSEMBLY__ */
+
+#ifdef HAVE_JUMP_LABEL
+#include 
+#endif
+
+#ifndef __ASSEMBLY__
 
 enum jump_label_type {
JUMP_LABEL_DISABLE = 0,
@@ -203,3 +214,5 @@ static inline bool static_key_enabled(struct static_key 
*key)
 }
 
 #endif /* _LINUX_JUMP_LABEL_H */
+
+#endif /* __ASSEMBLY__ */
-- 
2.1.0

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[PATCH] powerpc: secondary CPUs signal to master before setting active and online (fixes kernel BUG at kernel/smpboot.c:134!)

[Anton Blanchard]

Hi Ingo,

> At that point I thought the previous task_cpu() was somewhat ingrained
> in the scheduler and came up with the patch. If not, we could go on a
> hunt to see what else needs fixing.

I had another look. The scheduled does indeed make assumptions about the
previous task_cpu, but we have a hammer to fix it up called
select_fallback_rq.

I annotated select_fallback_rq, and did hit a case where the CPU was
not active. ppc64 patch below.

I think x86 have a similar (although harder to hit) issue. While it
does wait for the cpu_online bit to be set:

while (!cpu_online(cpu)) {
cpu_relax();
touch_nmi_watchdog();
}

The cpu_active bit is set after the cpu_online bit:

void set_cpu_online(unsigned int cpu, bool online)
{
if (online) {
cpumask_set_cpu(cpu, to_cpumask(cpu_online_bits));
cpumask_set_cpu(cpu, to_cpumask(cpu_active_bits));

If the CPU got delayed between the two stores (eg a KVM guest had the CPU
scheduled out), then we'd end up with cpu_active unset and hit the same
issue in select_fallback_rq.

Anton
--

I have a busy ppc64le KVM box where guests sometimes hit the infamous
"kernel BUG at kernel/smpboot.c:134!" issue during boot:

BUG_ON(td->cpu != smp_processor_id());

Basically a per CPU hotplug thread scheduled on the wrong CPU. The oops
output confirms it:

CPU: 0
Comm: watchdog/130

The problem is that we aren't ensuring the CPU active and online bits are set
before allowing the master to continue on. The master unparks the secondary
CPUs kthreads and the scheduler looks for a CPU to run on. It calls
select_task_rq and realises the suggested CPU is not in the cpus_allowed
mask. It then ends up in select_fallback_rq, and since the active and
online bits aren't set we choose some other CPU to run on.

Cc: sta...@vger.kernel.org
Signed-off-by: Anton Blanchard 
---
 arch/powerpc/kernel/smp.c | 9 -
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 71e186d..d40e46e 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -700,7 +700,6 @@ void start_secondary(void *unused)
smp_store_cpu_info(cpu);
set_dec(tb_ticks_per_jiffy);
preempt_disable();
-   cpu_callin_map[cpu] = 1;
 
if (smp_ops->setup_cpu)
smp_ops->setup_cpu(cpu);
@@ -739,6 +738,14 @@ void start_secondary(void *unused)
notify_cpu_starting(cpu);
set_cpu_online(cpu, true);
 
+   /*
+* CPU must be marked active and online before we signal back to the
+* master, because the scheduler needs to see the cpu_online and
+* cpu_active bits set.
+*/
+   smp_wmb();
+   cpu_callin_map[cpu] = 1;
+
local_irq_enable();
 
cpu_startup_entry(CPUHP_ONLINE);
-- 
2.1.0

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Re: [PATCH] kthread: kthread_bind fails to enforce CPU affinity (fixes kernel BUG at kernel/smpboot.c:134!)

[Anton Blanchard]

Hi Ingo,

> So we cannot call set_task_cpu() because in the normal life time 
> of a task the ->cpu value gets set on wakeup. So if a task is 
> blocked right now, and its affinity changes, it ought to get a 
> correct ->cpu selected on wakeup. The affinity mask and the 
> current value of ->cpu getting out of sync is thus 'normal'.
> 
> (Check for example how set_cpus_allowed_ptr() works: we first set 
> the new allowed mask, then do we migrate the task away if 
> necessary.)
> 
> In the kthread_bind() case this is explicitly assumed: it only 
> calls do_set_cpus_allowed().
> 
> But obviously the bug triggers in kernel/smpboot.c, and that 
> assert shows a real bug - and your patch makes the assert go 
> away, so the question is, how did the kthread get woken up and 
> put on a runqueue without its ->cpu getting set?

I started going down this line earlier today, and found things like:

select_task_rq_fair:

if (p->nr_cpus_allowed == 1)
return prev_cpu;

I tried returning cpumask_first(tsk_cpus_allowed()) instead, and while
I couldn't hit the BUG I did manage to get a scheduler lockup during
testing.

At that point I thought the previous task_cpu() was somewhat ingrained
in the scheduler and came up with the patch. If not, we could go on a
hunt to see what else needs fixing.

Anton
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Re: [PATCH] kthread: kthread_bind fails to enforce CPU affinity (fixes kernel BUG at kernel/smpboot.c:134!)

[Anton Blanchard]

Hi Linus,

> The __set_task_cpu() function does various other things too:
> 
> set_task_rq(p, cpu);
>   #ifdef CONFIG_SMP
> /*
>  * After ->cpu is set up to a new value, task_rq_lock(p, ...)
> can be
>  * successfuly executed on another CPU. We must ensure that
> updates of
>  * per-task data have been completed by this moment.
>  */
> smp_wmb();
> task_thread_info(p)->cpu = cpu;
> p->wake_cpu = cpu;
>   #endif
> 
> which makes me worry about just setting the thread_info->cpu value.
> That set_task_rq() initializes various group scheduling things, an
> dthat whole "wake_cpu" thing seems relevant too.

Yeah, I would definitely like the scheduler guys to weigh in on this,
especially considering how difficult it can be to hit.

Anton
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[PATCH] kthread: kthread_bind fails to enforce CPU affinity (fixes kernel BUG at kernel/smpboot.c:134!)

[Anton Blanchard]

I have a busy ppc64le KVM box where guests sometimes hit the infamous
"kernel BUG at kernel/smpboot.c:134!" issue during boot:

BUG_ON(td->cpu != smp_processor_id());

Basically a per CPU hotplug thread scheduled on the wrong CPU. The oops
output confirms it:

CPU: 0
Comm: watchdog/130

The issue is in kthread_bind where we set the cpus_allowed mask, but do
not touch task_thread_info(p)->cpu. The scheduler assumes the previously
scheduled CPU is in the cpus_allowed mask, but in this case we are
moving a thread to another CPU so it is not.

We used to call set_task_cpu which sets task_thread_info(p)->cpu (in fact
kthread_bind still has a comment suggesting this). That was removed in
e2912009fb7b ("sched: Ensure set_task_cpu() is never called on blocked
tasks").

Since we cannot call set_task_cpu (the task is in a sleeping state),
just do an explicit set of task_thread_info(p)->cpu.

Fixes: e2912009fb7b ("sched: Ensure set_task_cpu() is never called on blocked 
tasks")
Cc: sta...@vger.kernel.org
Signed-off-by: Anton Blanchard 
---
 kernel/kthread.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/kthread.c b/kernel/kthread.c
index 10e489c..e40ab1d 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -327,13 +327,14 @@ EXPORT_SYMBOL(kthread_create_on_node);
 
 static void __kthread_bind(struct task_struct *p, unsigned int cpu, long state)
 {
-   /* Must have done schedule() in kthread() before we set_task_cpu */
+   /* Must have done schedule() in kthread() before we change affinity */
if (!wait_task_inactive(p, state)) {
WARN_ON(1);
return;
}
/* It's safe because the task is inactive. */
do_set_cpus_allowed(p, cpumask_of(cpu));
+   task_thread_info(p)->cpu = cpu;
p->flags |= PF_NO_SETAFFINITY;
 }
 
-- 
2.1.0

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Re: [PATCH 1/2] tpm/tpm_ibmvtpm: Fail in ibmvtpm_get_data if driver_data is bad

[Anton Blanchard]

Hi,

> is this patchset still needed after Vicky's patch 
> "[tpmdd-devel] Fix NULL return in tpm_ibmvtpm_get_desired_dma"
> https://patchwork.ozlabs.org/patch/402315/
> 
> Ashley raised some concerns.
> 
> Since merge window is coming up, a fast reply is appreciated.

We definitely need a way to catch an invalid driver data pointer, but it
looks like that needs to be reworked after Vicky's patch.

Vicky could you look at all uses of ibmvtpm_get_data and make
sure we don't blindly dereference it? eg:

static int tpm_ibmvtpm_resume(struct device *dev)
{
struct ibmvtpm_dev *ibmvtpm = ibmvtpm_get_data(dev);
...

rc = plpar_hcall_norets(H_ENABLE_CRQ,
ibmvtpm->vdev->unit_address);

Anton
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Re: Confusing behaviour with /proc/sys/kernel/nmi_watchdog

[Anton Blanchard]

Hi Don,

> > commit 9919e39a1738 ("kvm: ensure hard lockup detection is disabled
> > by default") provided a way for the kernel to disable the hard
> > lockup detector at runtime.
> > 
> > I'm using it on ppc64 but notice some weird behaviour with the
> > nmi_watchdog procfs variable. At boot, that the hard lockup
> > detector appears to be enabled even when we disable it via
> > watchdog_enable_hardlockup_detector(false):
> > 
> > # cat /proc/sys/kernel/nmi_watchdog 
> > 1
> > 
> > I have to echo 0 to it then echo 1 again to enable it.
> 
> I believe Andrew answered the question for you, it's a WIP and we have
> patches to clean that up.

Thanks, yes good to see it being worked on.

> I don't see ppc64 watchdog support in arch/powerpc, is that something
> you are working with on implementing?

I've submitted it over on linuxppc-dev:

http://patchwork.ozlabs.org/patch/406802/

Anton
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Confusing behaviour with /proc/sys/kernel/nmi_watchdog

[Anton Blanchard]

Hi,

commit 9919e39a1738 ("kvm: ensure hard lockup detection is disabled by
default") provided a way for the kernel to disable the hard lockup
detector at runtime.

I'm using it on ppc64 but notice some weird behaviour with the
nmi_watchdog procfs variable. At boot, that the hard lockup
detector appears to be enabled even when we disable it via
watchdog_enable_hardlockup_detector(false):

# cat /proc/sys/kernel/nmi_watchdog 
1

I have to echo 0 to it then echo 1 again to enable it.

Anton
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[PATCH] quota: Add log level to printk

[Anton Blanchard]

Signed-off-by: Anton Blanchard 
---

Index: b/fs/quota/dquot.c
===
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -2743,7 +2743,7 @@ static int __init dquot_init(void)
for (i = 0; i < nr_hash; i++)
INIT_HLIST_HEAD(dquot_hash + i);
 
-   printk("Dquot-cache hash table entries: %ld (order %ld, %ld bytes)\n",
+   pr_info("Dquot-cache hash table entries: %ld (order %ld, %ld bytes)\n",
nr_hash, order, (PAGE_SIZE << order));
 
register_shrinker(&dqcache_shrinker);
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[PATCH] lib/raid6: Add log level to printks

[Anton Blanchard]

Signed-off-by: Anton Blanchard 
---

Index: b/lib/raid6/algos.c
===
--- a/lib/raid6/algos.c
+++ b/lib/raid6/algos.c
@@ -121,9 +121,9 @@ static inline const struct raid6_recov_c
raid6_2data_recov = best->data2;
raid6_datap_recov = best->datap;
 
-   printk("raid6: using %s recovery algorithm\n", best->name);
+   pr_info("raid6: using %s recovery algorithm\n", best->name);
} else
-   printk("raid6: Yikes! No recovery algorithm found!\n");
+   pr_err("raid6: Yikes! No recovery algorithm found!\n");
 
return best;
 }
@@ -157,18 +157,18 @@ static inline const struct raid6_calls *
bestperf = perf;
best = *algo;
}
-   printk("raid6: %-8s %5ld MB/s\n", (*algo)->name,
+   pr_info("raid6: %-8s %5ld MB/s\n", (*algo)->name,
   (perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2));
}
}
 
if (best) {
-   printk("raid6: using algorithm %s (%ld MB/s)\n",
+   pr_info("raid6: using algorithm %s (%ld MB/s)\n",
   best->name,
   (bestperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2));
raid6_call = *best;
} else
-   printk("raid6: Yikes!  No algorithm found!\n");
+   pr_err("raid6: Yikes!  No algorithm found!\n");
 
return best;
 }
@@ -194,7 +194,7 @@ int __init raid6_select_algo(void)
syndromes = (void *) __get_free_pages(GFP_KERNEL, 1);
 
if (!syndromes) {
-   printk("raid6: Yikes!  No memory available.\n");
+   pr_err("raid6: Yikes!  No memory available.\n");
return -ENOMEM;
}
 
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[PATCH] mm: page_alloc: Convert boot printks without log level to pr_info

[Anton Blanchard]

Signed-off-by: Anton Blanchard 
---

Index: b/mm/page_alloc.c
===
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3894,14 +3894,14 @@ void __ref build_all_zonelists(pg_data_t
else
page_group_by_mobility_disabled = 0;
 
-   printk("Built %i zonelists in %s order, mobility grouping %s.  "
+   pr_info("Built %i zonelists in %s order, mobility grouping %s.  "
"Total pages: %ld\n",
nr_online_nodes,
zonelist_order_name[current_zonelist_order],
page_group_by_mobility_disabled ? "off" : "on",
vm_total_pages);
 #ifdef CONFIG_NUMA
-   printk("Policy zone: %s\n", zone_names[policy_zone]);
+   pr_info("Policy zone: %s\n", zone_names[policy_zone]);
 #endif
 }
 
@@ -5333,33 +5333,33 @@ void __init free_area_init_nodes(unsigne
find_zone_movable_pfns_for_nodes();
 
/* Print out the zone ranges */
-   printk("Zone ranges:\n");
+   pr_info("Zone ranges:\n");
for (i = 0; i < MAX_NR_ZONES; i++) {
if (i == ZONE_MOVABLE)
continue;
-   printk(KERN_CONT "  %-8s ", zone_names[i]);
+   pr_info("  %-8s ", zone_names[i]);
if (arch_zone_lowest_possible_pfn[i] ==
arch_zone_highest_possible_pfn[i])
-   printk(KERN_CONT "empty\n");
+   pr_cont("empty\n");
else
-   printk(KERN_CONT "[mem %0#10lx-%0#10lx]\n",
+   pr_cont("[mem %0#10lx-%0#10lx]\n",
arch_zone_lowest_possible_pfn[i] << PAGE_SHIFT,
(arch_zone_highest_possible_pfn[i]
<< PAGE_SHIFT) - 1);
}
 
/* Print out the PFNs ZONE_MOVABLE begins at in each node */
-   printk("Movable zone start for each node\n");
+   pr_info("Movable zone start for each node\n");
for (i = 0; i < MAX_NUMNODES; i++) {
if (zone_movable_pfn[i])
-   printk("  Node %d: %#010lx\n", i,
+   pr_info("  Node %d: %#010lx\n", i,
   zone_movable_pfn[i] << PAGE_SHIFT);
}
 
/* Print out the early node map */
-   printk("Early memory node ranges\n");
+   pr_info("Early memory node ranges\n");
for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid)
-   printk("  node %3d: [mem %#010lx-%#010lx]\n", nid,
+   pr_info("  node %3d: [mem %#010lx-%#010lx]\n", nid,
   start_pfn << PAGE_SHIFT, (end_pfn << PAGE_SHIFT) - 1);
 
/* Initialise every node */
@@ -5495,7 +5495,7 @@ void __init mem_init_print_info(const ch
 
 #undef adj_init_size
 
-   printk("Memory: %luK/%luK available "
+   pr_info("Memory: %luK/%luK available "
   "(%luK kernel code, %luK rwdata, %luK rodata, "
   "%luK init, %luK bss, %luK reserved"
 #ifdef CONFIG_HIGHMEM
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Re: [PATCH v3] powerpc/iommu/ddw: Fix endianness

[Anton Blanchard]

Hi Alexey,

> rtas_call() accepts and returns values in CPU endianness.
> The ddw_query_response and ddw_create_response structs members are
> defined and treated as BE but as they are passed to rtas_call() as
> (u32 *) and they get byteswapped automatically, the data is
> CPU-endian. This fixes ddw_query_response and ddw_create_response
> definitions and use.
> 
> of_read_number() is designed to work with device tree cells - it
> assumes the input is big-endian and returns data in CPU-endian.
> However due to the ddw_create_response struct fix, create.addr_hi/lo
> are already CPU-endian so do not byteswap them.
> 
> ddw_avail is a pointer to the "ibm,ddw-applicable" property which
> contains 3 cells which are big-endian as it is a device tree.
> rtas_call() accepts a RTAS token in CPU-endian. This makes use of
> of_property_read_u32_array to byte swap and avoid the need for a
> number of be32_to_cpu calls.
> 
> Cc: sta...@vger.kernel.org # v3.13
> Cc: Benjamin Herrenschmidt 
> Reviewed-by: Anton Blanchard 
> [aik: folded Anton's patch with of_property_read_u32_array]
> Signed-off-by: Alexey Kardashevskiy 

Thanks for updating, looks good. Could we make it clear the bug is
present in 3.13-3.17 with:

Cc: sta...@vger.kernel.org # v3.13+

Acked-by: Anton Blanchard 

Anton
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Re: [PATCH 10/15] powerpc/mm: Add hooks for cxl

[Anton Blanchard]

Hi Mikey,

> We only map what a user processes maps and we tear it down when the
> process is teared down (on the file descriptor release).  So I think
> we are ok.  
> 
> Unless there's some lazy teardown you're alluding to that I'm missing?

I was trying to make sure things like the TLB batching code won't allow
a tlbie to be postponed until after a CAPI mapping is destroyed. It's
been ages since I looked at that part of the mm code.

Anton
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Re: [PATCH 09/15] powerpc/opal: Add PHB to cxl mode call

[Anton Blanchard]

> From: Ian Munsie 
> 
> This adds the OPAL call to change a PHB into cxl mode.
> 
> Signed-off-by: Ian Munsie 
> Signed-off-by: Michael Neuling 

Reviewed-by: Anton Blanchard 
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Re: [PATCH 10/15] powerpc/mm: Add hooks for cxl

[Anton Blanchard]

> From: Ian Munsie 
> 
> This add a hook into tlbie() so that we use global invalidations when
> there are cxl contexts active.
> 
> Normally cxl snoops broadcast tlbie.  cxl can have TLB entries
> invalidated via MMIO, but we aren't doing that yet.  So for now we
> are just disabling local tlbies when cxl contexts are active.  In
> future we can make tlbie() local mode smarter so that it invalidates
> cxl contexts explicitly when it needs to.
> 
> This also adds a hooks for when SLBs are invalidated to ensure any
> corresponding SLBs in cxl are also invalidated at the same time.
> 
> Signed-off-by: Ian Munsie 
> Signed-off-by: Michael Neuling 

> + use_local = local && mmu_has_feature(MMU_FTR_TLBIEL) && 
> !cxl_ctx_in_use();

Seems reasonable until we can get the MMIO based optimisation in.

Will all CAPI cached translations be invalidated before we finish using
a CAPI context? And conversely, could CAPI cache any translations when a
context isn't active? I'm mostly concerned that we can't have a
situation where badly behaving userspace could result in a stale
translation.

>   spu_flush_all_slbs(mm);
>  #endif
> + cxl_slbia(mm);

>   spu_flush_all_slbs(mm);
>  #endif
> + cxl_slbia(mm);

>   spu_flush_all_slbs(mm);
>  #endif
> + cxl_slbia(mm);

>   spu_flush_all_slbs(mm);
>  #endif
> + cxl_slbia(mm);

Should we combine the SPU vs CXL callouts into something common -
perhaps copro_flush_all_slbs()?

Anton
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Re: [PATCH 02/15] powerpc/cell: Move data segment faulting code out of cell platform

[Anton Blanchard]

> From: Ian Munsie 
> 
> __spu_trap_data_seg() currently contains code to determine the VSID
> and ESID required for a particular EA and mm struct.
> 
> This code is generically useful for other co-processors.  This moves
> the code of the cell platform so it can be used by other powerpc code.

Could we also mention:

and adds 1TB segment support.

> Signed-off-by: Ian Munsie 
> Signed-off-by: Michael Neuling 

Reviewed-by: Anton Blanchard 

Anton
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Re: [PATCH 01/15] powerpc/cell: Move spu_handle_mm_fault() out of cell platform

[Anton Blanchard]

> From: Ian Munsie 
> 
> Currently spu_handle_mm_fault() is in the cell platform.
> 
> This code is generically useful for other non-cell co-processors on
> powerpc.
> 
> This patch moves this function out of the cell platform into
> arch/powerpc/mm so that others may use it.
> 
> Signed-off-by: Ian Munsie 
> Signed-off-by: Michael Neuling 

Reviewed-by: Anton Blanchard 

Anton
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Re: [PATCH v2] powerpc/iommu/ddw: Fix endianness

[Anton Blanchard]

Hi Alexey,

> ddw_avail is a pointer to the "ibm,ddw-applicable" property which
> contains 3 cells which are big-endian as it is a device tree.
> rtas_call() accepts a RTAS token in CPU-endian. This converts RTAS
> tokens from big-endian to CPU-endian. Since every token is used once
> till guest is rebooted, there is no much sense in caching RTAS tokens
> in CPU-endian.

I see a few sparse endian warnings with this. This patch (that applies
on top of yours) uses of_property_read_u32_array to byte swap and avoid
the need for a number of be32_to_cpu calls.

Can you verify this works and then fold it into yours? Also mark it for
inclusion in stable v3.13+.

You can add:

Reviewed-by: Anton Blanchard 

Thanks!
Anton

Index: b/arch/powerpc/platforms/pseries/iommu.c
===
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -725,16 +725,18 @@ static void remove_ddw(struct device_nod
 {
struct dynamic_dma_window_prop *dwp;
struct property *win64;
-   const u32 *ddw_avail;
+   u32 ddw_avail[3];
u64 liobn;
-   int len, ret = 0;
+   int ret = 0;
+
+   ret = of_property_read_u32_array(np, "ibm,ddw-applicable",
+&ddw_avail[0], 3);
 
-   ddw_avail = of_get_property(np, "ibm,ddw-applicable", &len);
win64 = of_find_property(np, DIRECT64_PROPNAME, NULL);
if (!win64)
return;
 
-   if (!ddw_avail || len < 3 * sizeof(u32) || win64->length < sizeof(*dwp))
+   if (ret || win64->length < sizeof(*dwp))
goto delprop;
 
dwp = win64->value;
@@ -750,7 +752,7 @@ static void remove_ddw(struct device_nod
pr_debug("%s successfully cleared tces in window.\n",
 np->full_name);
 
-   ret = rtas_call(be32_to_cpu(ddw_avail[2]), 1, 1, NULL, liobn);
+   ret = rtas_call(ddw_avail[2], 1, 1, NULL, liobn);
if (ret)
pr_warning("%s: failed to remove direct window: rtas returned "
"%d to ibm,remove-pe-dma-window(%x) %llx\n",
@@ -841,7 +843,7 @@ static int query_ddw(struct pci_dev *dev
cfg_addr = edev->pe_config_addr;
buid = edev->phb->buid;
 
-   ret = rtas_call(be32_to_cpu(ddw_avail[0]), 3, 5, (u32 *)query,
+   ret = rtas_call(ddw_avail[0], 3, 5, (u32 *)query,
  cfg_addr, BUID_HI(buid), BUID_LO(buid));
dev_info(&dev->dev, "ibm,query-pe-dma-windows(%x) %x %x %x"
" returned %d\n", ddw_avail[0], cfg_addr, BUID_HI(buid),
@@ -872,7 +874,7 @@ static int create_ddw(struct pci_dev *de
 
do {
/* extra outputs are LIOBN and dma-addr (hi, lo) */
-   ret = rtas_call(be32_to_cpu(ddw_avail[1]), 5, 4, (u32 *)create,
+   ret = rtas_call(ddw_avail[1], 5, 4, (u32 *)create,
cfg_addr, BUID_HI(buid), BUID_LO(buid),
page_shift, window_shift);
} while (rtas_busy_delay(ret));
@@ -911,7 +913,7 @@ static u64 enable_ddw(struct pci_dev *de
int page_shift;
u64 dma_addr, max_addr;
struct device_node *dn;
-   const u32 *uninitialized_var(ddw_avail);
+   u32 ddw_avail[3];
struct direct_window *window;
struct property *win64;
struct dynamic_dma_window_prop *ddwprop;
@@ -943,8 +945,9 @@ static u64 enable_ddw(struct pci_dev *de
 * for the given node in that order.
 * the property is actually in the parent, not the PE
 */
-   ddw_avail = of_get_property(pdn, "ibm,ddw-applicable", &len);
-   if (!ddw_avail || len < 3 * sizeof(u32))
+   ret = of_property_read_u32_array(pdn, "ibm,ddw-applicable",
+&ddw_avail[0], 3);
+   if (ret)
goto out_failed;
 
/*
--
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[PATCH 2/2] tpm/tpm_ibmvtpm: Remove unnecessary casts

[Anton Blanchard]

There is no need to cast from a void pointer to another pointer.

Signed-off-by: Anton Blanchard 
---

Index: b/drivers/char/tpm/tpm_ibmvtpm.c
===
--- a/drivers/char/tpm/tpm_ibmvtpm.c
+++ b/drivers/char/tpm/tpm_ibmvtpm.c
@@ -65,7 +65,7 @@ static struct ibmvtpm_dev *ibmvtpm_get_d
struct tpm_chip *chip = dev_get_drvdata(dev);
 
BUG_ON(!chip);
-   return (struct ibmvtpm_dev *)TPM_VPRIV(chip);
+   return TPM_VPRIV(chip);
 }
 
 /**
@@ -83,7 +83,7 @@ static int tpm_ibmvtpm_recv(struct tpm_c
u16 len;
int sig;
 
-   ibmvtpm = (struct ibmvtpm_dev *)TPM_VPRIV(chip);
+   ibmvtpm = TPM_VPRIV(chip);
 
if (!ibmvtpm->rtce_buf) {
dev_err(ibmvtpm->dev, "ibmvtpm device is not ready\n");
@@ -127,7 +127,7 @@ static int tpm_ibmvtpm_send(struct tpm_c
u64 *word = (u64 *) &crq;
int rc;
 
-   ibmvtpm = (struct ibmvtpm_dev *)TPM_VPRIV(chip);
+   ibmvtpm = TPM_VPRIV(chip);
 
if (!ibmvtpm->rtce_buf) {
dev_err(ibmvtpm->dev, "ibmvtpm device is not ready\n");
@@ -521,7 +521,7 @@ static void ibmvtpm_crq_process(struct i
  **/
 static irqreturn_t ibmvtpm_interrupt(int irq, void *vtpm_instance)
 {
-   struct ibmvtpm_dev *ibmvtpm = (struct ibmvtpm_dev *) vtpm_instance;
+   struct ibmvtpm_dev *ibmvtpm = vtpm_instance;
struct ibmvtpm_crq *crq;
 
/* while loop is needed for initial setup (get version and
--
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[PATCH 1/2] tpm/tpm_ibmvtpm: Fail in ibmvtpm_get_data if driver_data is bad

[Anton Blanchard]

I'm looking at an oops in tpm_ibmvtpm_get_desired_dma:

  28:   00 00 20 39 li  r9,0
  2c:   10 00 01 e8 ld  r0,16(r1)
  30:   28 00 69 80 lwz r3,40(r9)

We set r9 to 0 then load r9+40. The problem is actually in
ibmvtpm_get_data, it can return NULL but the rest of the driver
never expects it.

Add a BUG_ON in ibmvtpm_get_data. We still need to identify the root
cause but at least this makes it obvious what went wrong.

Cc: sta...@vger.kernel.org
Signed-off-by: Anton Blanchard 
---

diff --git a/drivers/char/tpm/tpm_ibmvtpm.c b/drivers/char/tpm/tpm_ibmvtpm.c
index af74c57..0d1eeba 100644
--- a/drivers/char/tpm/tpm_ibmvtpm.c
+++ b/drivers/char/tpm/tpm_ibmvtpm.c
@@ -63,9 +63,9 @@ static int ibmvtpm_send_crq(struct vio_dev *vdev, u64 w1, u64 
w2)
 static struct ibmvtpm_dev *ibmvtpm_get_data(const struct device *dev)
 {
struct tpm_chip *chip = dev_get_drvdata(dev);
-   if (chip)
-   return (struct ibmvtpm_dev *)TPM_VPRIV(chip);
-   return NULL;
+
+   BUG_ON(!chip);
+   return (struct ibmvtpm_dev *)TPM_VPRIV(chip);
 }
 
 /**
--
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[tip:perf/core] perf symbols: Ignore stripped vmlinux and fallback to kallsyms

[tip-bot for Anton Blanchard]

Commit-ID:  d0b0d0406fe6743e734e1ba780155f8db5f713e6
Gitweb: http://git.kernel.org/tip/d0b0d0406fe6743e734e1ba780155f8db5f713e6
Author: Anton Blanchard 
AuthorDate: Tue, 9 Sep 2014 08:59:29 +1000
Committer:  Arnaldo Carvalho de Melo 
CommitDate: Wed, 17 Sep 2014 17:08:10 -0300

perf symbols: Ignore stripped vmlinux and fallback to kallsyms

If a vmlinux is stripped, perf will use it and ignore kallsyms. We
end up with useless profiles where everything maps to a few
runtime symbols:

63.39%   swapper  [kernel.kallsyms]   [k] hcall_real_table
 4.90%  beam.smp  [kernel.kallsyms]   [k] hcall_real_table
 4.44%  beam.smp  [kernel.kallsyms]   [k] __sched_text_start
 3.72%  beam.smp  [kernel.kallsyms]   [k] __run_at_kexec

Detect this case and fallback to using kallsyms. This fixes the issue:

62.81%   swapper  [kernel.kallsyms]   [k] snooze_loop
 4.44%  beam.smp  [kernel.kallsyms]   [k] __schedule
 0.91%  beam.smp  [kernel.kallsyms]   [k] _switch
 0.73%  beam.smp  [kernel.kallsyms]   [k] put_prev_entity

Signed-off-by: Anton Blanchard 
Acked-by: Namhyung Kim 
Cc: Ingo Molnar 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20140909085929.4a5a81f0@kryten
Signed-off-by: Arnaldo Carvalho de Melo 
---
 tools/perf/util/symbol-elf.c | 8 
 1 file changed, 8 insertions(+)

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 9c9b27f..2a92e10 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -717,6 +717,14 @@ int dso__load_sym(struct dso *dso, struct map *map,
symbols__delete(&dso->symbols[map->type]);
 
if (!syms_ss->symtab) {
+   /*
+* If the vmlinux is stripped, fail so we will fall back
+* to using kallsyms. The vmlinux runtime symbols aren't
+* of much use.
+*/
+   if (dso->kernel)
+   goto out_elf_end;
+
syms_ss->symtab  = syms_ss->dynsym;
syms_ss->symshdr = syms_ss->dynshdr;
}
--
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[tip:perf/core] perf symbols: Add path to Ubuntu kernel debuginfo file

[tip-bot for Anton Blanchard]

Commit-ID:  c657f423aed0d836c807ea1d6d8d28b3914446fa
Gitweb: http://git.kernel.org/tip/c657f423aed0d836c807ea1d6d8d28b3914446fa
Author: Anton Blanchard 
AuthorDate: Mon, 15 Sep 2014 16:57:56 -0300
Committer:  Arnaldo Carvalho de Melo 
CommitDate: Wed, 17 Sep 2014 17:08:10 -0300

perf symbols: Add path to Ubuntu kernel debuginfo file

Ubuntu places the kernel debuginfo in /usr/lib/debug/boot/vmlinux-*

Signed-off-by: Anton Blanchard 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
echo Link: http://lkml.kernel.org/n/tip-`ranpwd -l 24`@git.kernel.org
Link: http://lkml.kernel.org/r/20140909091152.2698c0f7@kryten
[ Adapted it to use the perf.data file kernel version as in 0a7e6d1b6844 ]
Signed-off-by: Arnaldo Carvalho de Melo 
---
 tools/perf/util/symbol.c | 8 +++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 1adb143..be84f7a 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1757,7 +1757,7 @@ static int vmlinux_path__init(struct perf_session_env 
*env)
char bf[PATH_MAX];
char *kernel_version;
 
-   vmlinux_path = malloc(sizeof(char *) * 5);
+   vmlinux_path = malloc(sizeof(char *) * 6);
if (vmlinux_path == NULL)
return -1;
 
@@ -1788,6 +1788,12 @@ static int vmlinux_path__init(struct perf_session_env 
*env)
if (vmlinux_path[vmlinux_path__nr_entries] == NULL)
goto out_fail;
++vmlinux_path__nr_entries;
+   snprintf(bf, sizeof(bf), "/usr/lib/debug/boot/vmlinux-%s",
+kernel_version);
+   vmlinux_path[vmlinux_path__nr_entries] = strdup(bf);
+   if (vmlinux_path[vmlinux_path__nr_entries] == NULL)
+   goto out_fail;
+++vmlinux_path__nr_entries;
snprintf(bf, sizeof(bf), "/lib/modules/%s/build/vmlinux", 
kernel_version);
vmlinux_path[vmlinux_path__nr_entries] = strdup(bf);
if (vmlinux_path[vmlinux_path__nr_entries] == NULL)
--
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[tip:perf/core] perf tools powerpc: Fix build issue when DWARF support is disabled

[tip-bot for Anton Blanchard]

Commit-ID:  65ccb4faae872b63dd8f5fbc83d0195e3dfabf0d
Gitweb: http://git.kernel.org/tip/65ccb4faae872b63dd8f5fbc83d0195e3dfabf0d
Author: Anton Blanchard 
AuthorDate: Mon, 25 Aug 2014 18:25:06 +1000
Committer:  Arnaldo Carvalho de Melo 
CommitDate: Wed, 17 Sep 2014 17:08:07 -0300

perf tools powerpc: Fix build issue when DWARF support is disabled

The powerpc skip callchain code uses DWARF, so we must disable it if
DWARF is disabled.

Signed-off-by: Anton Blanchard 
Cc: Ingo Molnar 
Cc: Michael Ellerman 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Sukadev Bhattiprolu 
Link: http://lkml.kernel.org/r/20140825182506.2be6512d@kryten
Signed-off-by: Arnaldo Carvalho de Melo 
---
 tools/perf/arch/powerpc/Makefile |  2 +-
 tools/perf/config/Makefile   | 10 ++
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/tools/perf/arch/powerpc/Makefile b/tools/perf/arch/powerpc/Makefile
index b92219b..6f7782b 100644
--- a/tools/perf/arch/powerpc/Makefile
+++ b/tools/perf/arch/powerpc/Makefile
@@ -1,6 +1,6 @@
 ifndef NO_DWARF
 PERF_HAVE_DWARF_REGS := 1
 LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/dwarf-regs.o
+LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/skip-callchain-idx.o
 endif
 LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/header.o
-LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/skip-callchain-idx.o
diff --git a/tools/perf/config/Makefile b/tools/perf/config/Makefile
index 75d4c23..98c9fd1 100644
--- a/tools/perf/config/Makefile
+++ b/tools/perf/config/Makefile
@@ -48,10 +48,6 @@ ifneq ($(ARCH),$(filter $(ARCH),x86 arm))
   NO_LIBDW_DWARF_UNWIND := 1
 endif
 
-ifeq ($(ARCH),powerpc)
-  CFLAGS += -DHAVE_SKIP_CALLCHAIN_IDX
-endif
-
 ifeq ($(LIBUNWIND_LIBS),)
   NO_LIBUNWIND := 1
 else
@@ -378,6 +374,12 @@ ifndef NO_LIBELF
   endif # NO_DWARF
 endif # NO_LIBELF
 
+ifeq ($(ARCH),powerpc)
+  ifndef NO_DWARF
+CFLAGS += -DHAVE_SKIP_CALLCHAIN_IDX
+  endif
+endif
+
 ifndef NO_LIBUNWIND
   ifneq ($(feature-libunwind), 1)
 msg := $(warning No libunwind found. Please install libunwind-dev[el] >= 
1.1 and/or set LIBUNWIND_DIR);
--
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[PATCH 2/2] powerpc: Use CONFIG_ARCH_HAS_FAST_MULTIPLIER

[Anton Blanchard]

I ran some tests to compare hash_64 using shifts and multiplies.
The results:

POWER6: ~2x slower
POWER7: ~2x faster
POWER8: ~2x faster

Now we have a proper config option, select
CONFIG_ARCH_HAS_FAST_MULTIPLIER on POWER7 and POWER8.

Signed-off-by: Anton Blanchard 
---

Index: b/arch/powerpc/platforms/Kconfig.cputype
===
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -116,10 +116,12 @@ config POWER6_CPU
 config POWER7_CPU
bool "POWER7"
depends on PPC_BOOK3S_64
+   select ARCH_HAS_FAST_MULTIPLIER
 
 config POWER8_CPU
bool "POWER8"
depends on PPC_BOOK3S_64
+   select ARCH_HAS_FAST_MULTIPLIER
 
 config E5500_CPU
bool "Freescale e5500"
--
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