Once stop_machine() is gone from the CPU offline path, we won't be able
to depend on disabling preemption to prevent CPUs from going offline
from under us.
Use the get/put_online_cpus_atomic() APIs to prevent CPUs from going
offline, while invoking from atomic context.
Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Cc: Gleb Natapov <g...@redhat.com>
Cc: Alexander Graf <ag...@suse.de>
Cc: Rob Herring <rob.herr...@calxeda.com>
Cc: Grant Likely <grant.lik...@secretlab.ca>
Cc: Kumar Gala <ga...@kernel.crashing.org>
Cc: Zhao Chenhui <chenhui.z...@freescale.com>
Cc: linuxppc-...@lists.ozlabs.org
Cc: k...@vger.kernel.org
Cc: kvm-ppc@vger.kernel.org
Cc: oprofile-l...@lists.sf.net
Cc: cbe-oss-...@lists.ozlabs.org
Signed-off-by: Srivatsa S. Bhat <srivatsa.b...@linux.vnet.ibm.com>
---
arch/powerpc/kernel/irq.c | 7 ++++++-
arch/powerpc/kernel/machine_kexec_64.c | 4 ++--
arch/powerpc/kernel/smp.c | 2 ++
arch/powerpc/kvm/book3s_hv.c | 5 +++--
arch/powerpc/mm/mmu_context_nohash.c | 3 +++
arch/powerpc/oprofile/cell/spu_profiler.c | 3 +++
arch/powerpc/oprofile/cell/spu_task_sync.c | 4 ++++
arch/powerpc/oprofile/op_model_cell.c | 6 ++++++
8 files changed, 29 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index ca39bac..41e9961 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -45,6 +45,7 @@
#include <linux/irq.h>
#include <linux/seq_file.h>
#include <linux/cpumask.h>
+#include <linux/cpu.h>
#include <linux/profile.h>
#include <linux/bitops.h>
#include <linux/list.h>
@@ -410,7 +411,10 @@ void migrate_irqs(void)
unsigned int irq;
static int warned;
cpumask_var_t mask;
- const struct cpumask *map = cpu_online_mask;
+ const struct cpumask *map;
+
+ get_online_cpus_atomic();
+ map = cpu_online_mask;
alloc_cpumask_var(&mask, GFP_ATOMIC);
@@ -436,6 +440,7 @@ void migrate_irqs(void)
}
free_cpumask_var(mask);
+ put_online_cpus_atomic();
local_irq_enable();
mdelay(1);
diff --git a/arch/powerpc/kernel/machine_kexec_64.c
b/arch/powerpc/kernel/machine_kexec_64.c
index 611acdf..38f6d75 100644
--- a/arch/powerpc/kernel/machine_kexec_64.c
+++ b/arch/powerpc/kernel/machine_kexec_64.c
@@ -187,7 +187,7 @@ static void kexec_prepare_cpus_wait(int wait_state)
int my_cpu, i, notified=-1;
hw_breakpoint_disable();
- my_cpu = get_cpu();
+ my_cpu = get_online_cpus_atomic();
/* Make sure each CPU has at least made it to the state we need.
*
* FIXME: There is a (slim) chance of a problem if not all of the CPUs
@@ -266,7 +266,7 @@ static void kexec_prepare_cpus(void)
*/
kexec_prepare_cpus_wait(KEXEC_STATE_REAL_MODE);
- put_cpu();
+ put_online_cpus_atomic();
}
#else /* ! SMP */
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index ee7ac5e..2123bec 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -277,9 +277,11 @@ void smp_send_debugger_break(void)
if (unlikely(!smp_ops))
return;
+ get_online_cpus_atomic();
for_each_online_cpu(cpu)
if (cpu != me)
do_message_pass(cpu, PPC_MSG_DEBUGGER_BREAK);
+ put_online_cpus_atomic();
}
#endif
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 2efa9dd..9d8a973 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -28,6 +28,7 @@
#include <linux/fs.h>
#include <linux/anon_inodes.h>
#include <linux/cpumask.h>
+#include <linux/cpu.h>
#include <linux/spinlock.h>
#include <linux/page-flags.h>
#include <linux/srcu.h>
@@ -78,7 +79,7 @@ void kvmppc_fast_vcpu_kick(struct kvm_vcpu *vcpu)
++vcpu->stat.halt_wakeup;
}
- me = get_cpu();
+ me = get_online_cpus_atomic();
/* CPU points to the first thread of the core */
if (cpu != me && cpu >= 0 && cpu < nr_cpu_ids) {
@@ -88,7 +89,7 @@ void kvmppc_fast_vcpu_kick(struct kvm_vcpu *vcpu)
else if (cpu_online(cpu))
smp_send_reschedule(cpu);
}
- put_cpu();
+ put_online_cpus_atomic();
}
/*
diff --git a/arch/powerpc/mm/mmu_context_nohash.c
b/arch/powerpc/mm/mmu_context_nohash.c
index e779642..c7bdcb4 100644
--- a/arch/powerpc/mm/mmu_context_nohash.c
+++ b/arch/powerpc/mm/mmu_context_nohash.c
@@ -194,6 +194,8 @@ void switch_mmu_context(struct mm_struct *prev, struct
mm_struct *next)
unsigned int i, id, cpu = smp_processor_id();
unsigned long *map;
+ get_online_cpus_atomic();
+
/* No lockless fast path .. yet */
raw_spin_lock(&context_lock);
@@ -280,6 +282,7 @@ void switch_mmu_context(struct mm_struct *prev, struct
mm_struct *next)
pr_hardcont(" -> %d\n", id);
set_context(id, next->pgd);
raw_spin_unlock(&context_lock);
+ put_online_cpus_atomic();
}
/*
diff --git a/arch/powerpc/oprofile/cell/spu_profiler.c
b/arch/powerpc/oprofile/cell/spu_profiler.c
index b129d00..ab6e6c1 100644
--- a/arch/powerpc/oprofile/cell/spu_profiler.c
+++ b/arch/powerpc/oprofile/cell/spu_profiler.c
@@ -14,6 +14,7 @@
#include <linux/hrtimer.h>
#include <linux/smp.h>
+#include <linux/cpu.h>
#include <linux/slab.h>
#include <asm/cell-pmu.h>
#include <asm/time.h>
@@ -142,6 +143,7 @@ static enum hrtimer_restart profile_spus(struct hrtimer
*timer)
if (!spu_prof_running)
goto stop;
+ get_online_cpus_atomic();
for_each_online_cpu(cpu) {
if (cbe_get_hw_thread_id(cpu))
continue;
@@ -177,6 +179,7 @@ static enum hrtimer_restart profile_spus(struct hrtimer
*timer)
oprof_spu_smpl_arry_lck_flags);
}
+ put_online_cpus_atomic();
smp_wmb(); /* insure spu event buffer updates are written */
/* don't want events intermingled... */
diff --git a/arch/powerpc/oprofile/cell/spu_task_sync.c
b/arch/powerpc/oprofile/cell/spu_task_sync.c
index 28f1af2..8464ef6 100644
--- a/arch/powerpc/oprofile/cell/spu_task_sync.c
+++ b/arch/powerpc/oprofile/cell/spu_task_sync.c
@@ -28,6 +28,7 @@
#include <linux/oprofile.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
+#include <linux/cpu.h>
#include "pr_util.h"
#define RELEASE_ALL 9999
@@ -448,11 +449,14 @@ static int number_of_online_nodes(void)
{
u32 cpu; u32 tmp;
int nodes = 0;
+
+ get_online_cpus_atomic();
for_each_online_cpu(cpu) {
tmp = cbe_cpu_to_node(cpu) + 1;
if (tmp > nodes)
nodes++;
}
+ put_online_cpus_atomic();
return nodes;
}
diff --git a/arch/powerpc/oprofile/op_model_cell.c
b/arch/powerpc/oprofile/op_model_cell.c
index b9589c1..c9bb028 100644
--- a/arch/powerpc/oprofile/op_model_cell.c
+++ b/arch/powerpc/oprofile/op_model_cell.c
@@ -22,6 +22,7 @@
#include <linux/oprofile.h>
#include <linux/percpu.h>
#include <linux/smp.h>
+#include <linux/cpu.h>
#include <linux/spinlock.h>
#include <linux/timer.h>
#include <asm/cell-pmu.h>
@@ -463,6 +464,7 @@ static void cell_virtual_cntr(unsigned long data)
* not both playing with the counters on the same node.
*/
+ get_online_cpus_atomic();
spin_lock_irqsave(&cntr_lock, flags);
prev_hdw_thread = hdw_thread;
@@ -550,6 +552,7 @@ static void cell_virtual_cntr(unsigned long data)
}
spin_unlock_irqrestore(&cntr_lock, flags);
+ put_online_cpus_atomic();
mod_timer(&timer_virt_cntr, jiffies + HZ / 10);
}
@@ -608,6 +611,8 @@ static void spu_evnt_swap(unsigned long data)
/* Make sure spu event interrupt handler and spu event swap
* don't access the counters simultaneously.
*/
+
+ get_online_cpus_atomic();
spin_lock_irqsave(&cntr_lock, flags);
cur_spu_evnt_phys_spu_indx = spu_evnt_phys_spu_indx;
@@ -673,6 +678,7 @@ static void spu_evnt_swap(unsigned long data)
}
spin_unlock_irqrestore(&cntr_lock, flags);
+ put_online_cpus_atomic();
/* swap approximately every 0.1 seconds */
mod_timer(&timer_spu_event_swap, jiffies + HZ / 25);
--
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