Re: [patch V3 13/37] mips/mm/highmem: Switch to generic kmap atomic
On 2021-01-09 01:33:52 [+0100], Thomas Bogendoerfer wrote:
> On Sat, Jan 09, 2021 at 12:58:05AM +0100, Thomas Bogendoerfer wrote:
> > On Fri, Jan 08, 2021 at 08:20:43PM +, Paul Cercueil wrote:
> > > Hi Thomas,
> > >
> > > 5.11 does not boot anymore on Ingenic SoCs, I bisected it to this commit.
> > >
> > > Any idea what could be happening?
> >
> > not yet, kernel crash log of a Malta QEMU is below.
>
> update:
>
> This dirty hack lets the Malta QEMU boot again:
>
> diff --git a/mm/highmem.c b/mm/highmem.c
> index c3a9ea7875ef..190cdda1149d 100644
> --- a/mm/highmem.c
> +++ b/mm/highmem.c
> @@ -515,7 +515,7 @@ void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t
> prot)
> vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
> BUG_ON(!pte_none(*(kmap_pte - idx)));
> pteval = pfn_pte(pfn, prot);
> - set_pte_at(&init_mm, vaddr, kmap_pte - idx, pteval);
> + set_pte(kmap_pte - idx, pteval);
> arch_kmap_local_post_map(vaddr, pteval);
> current->kmap_ctrl.pteval[kmap_local_idx()] = pteval;
> preempt_enable();
>
> set_pte_at() tries to update cache and could do an kmap_atomic() there.
So the old implementation used set_pte() while the new one uses
set_pte_at().
> Not sure, if this is allowed at this point.
The problem is the recursion
kmap_atomic() -> __update_cache() -> kmap_atomic()
and kmap_local_idx_push() runs out if index space before stack space.
I'm not sure if the __update_cache() worked for highmem. It has been
added for that in commit
f4281bba81810 ("MIPS: Handle highmem pages in __update_cache")
but it assumes that the address returned by kmap_atomic() is the same or
related enough for flush_data_cache_page() to work.
> Thomas.
>
Sebastian
Re: [patch V3 13/37] mips/mm/highmem: Switch to generic kmap atomic
> Am 10.01.2021 um 12:35 schrieb Paul Cercueil : > > Hi Thomas, > > Le sam. 9 janv. 2021 à 1:33, Thomas Bogendoerfer > a écrit : >> On Sat, Jan 09, 2021 at 12:58:05AM +0100, Thomas Bogendoerfer wrote: >>> On Fri, Jan 08, 2021 at 08:20:43PM +, Paul Cercueil wrote: >>> > Hi Thomas, >>> > >>> > 5.11 does not boot anymore on Ingenic SoCs, I bisected it to this commit. Just for completeness, I have no such problems booting CI20/jz4780 or Skytone400/jz4730 (unpublished work) with 5.11-rc2. But may depend on board capabilites (ram size, memory layout or something else). >>> > >>> > Any idea what could be happening? >>> not yet, kernel crash log of a Malta QEMU is below. >> update: >> This dirty hack lets the Malta QEMU boot again: >> diff --git a/mm/highmem.c b/mm/highmem.c >> index c3a9ea7875ef..190cdda1149d 100644 >> --- a/mm/highmem.c >> +++ b/mm/highmem.c >> @@ -515,7 +515,7 @@ void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t >> prot) >> vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); >> BUG_ON(!pte_none(*(kmap_pte - idx))); >> pteval = pfn_pte(pfn, prot); >> -set_pte_at(&init_mm, vaddr, kmap_pte - idx, pteval); >> +set_pte(kmap_pte - idx, pteval); >> arch_kmap_local_post_map(vaddr, pteval); >> current->kmap_ctrl.pteval[kmap_local_idx()] = pteval; >> preempt_enable(); >> set_pte_at() tries to update cache and could do an kmap_atomic() there. >> Not sure, if this is allowed at this point. > > Yes, I can confirm that your workaround works here too. > > Cheers, > -Paul > >
Re: [patch V3 13/37] mips/mm/highmem: Switch to generic kmap atomic
Hi Thomas, Le sam. 9 janv. 2021 à 1:33, Thomas Bogendoerfer a écrit : On Sat, Jan 09, 2021 at 12:58:05AM +0100, Thomas Bogendoerfer wrote: On Fri, Jan 08, 2021 at 08:20:43PM +, Paul Cercueil wrote: > Hi Thomas, > > 5.11 does not boot anymore on Ingenic SoCs, I bisected it to this commit. > > Any idea what could be happening? not yet, kernel crash log of a Malta QEMU is below. update: This dirty hack lets the Malta QEMU boot again: diff --git a/mm/highmem.c b/mm/highmem.c index c3a9ea7875ef..190cdda1149d 100644 --- a/mm/highmem.c +++ b/mm/highmem.c @@ -515,7 +515,7 @@ void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot) vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); BUG_ON(!pte_none(*(kmap_pte - idx))); pteval = pfn_pte(pfn, prot); - set_pte_at(&init_mm, vaddr, kmap_pte - idx, pteval); + set_pte(kmap_pte - idx, pteval); arch_kmap_local_post_map(vaddr, pteval); current->kmap_ctrl.pteval[kmap_local_idx()] = pteval; preempt_enable(); set_pte_at() tries to update cache and could do an kmap_atomic() there. Not sure, if this is allowed at this point. Yes, I can confirm that your workaround works here too. Cheers, -Paul
Re: [patch V3 13/37] mips/mm/highmem: Switch to generic kmap atomic
On Sat, Jan 09, 2021 at 12:58:05AM +0100, Thomas Bogendoerfer wrote: > On Fri, Jan 08, 2021 at 08:20:43PM +, Paul Cercueil wrote: > > Hi Thomas, > > > > 5.11 does not boot anymore on Ingenic SoCs, I bisected it to this commit. > > > > Any idea what could be happening? > > not yet, kernel crash log of a Malta QEMU is below. update: This dirty hack lets the Malta QEMU boot again: diff --git a/mm/highmem.c b/mm/highmem.c index c3a9ea7875ef..190cdda1149d 100644 --- a/mm/highmem.c +++ b/mm/highmem.c @@ -515,7 +515,7 @@ void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot) vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); BUG_ON(!pte_none(*(kmap_pte - idx))); pteval = pfn_pte(pfn, prot); - set_pte_at(&init_mm, vaddr, kmap_pte - idx, pteval); + set_pte(kmap_pte - idx, pteval); arch_kmap_local_post_map(vaddr, pteval); current->kmap_ctrl.pteval[kmap_local_idx()] = pteval; preempt_enable(); set_pte_at() tries to update cache and could do an kmap_atomic() there. Not sure, if this is allowed at this point. Thomas. -- Crap can work. Given enough thrust pigs will fly, but it's not necessarily a good idea.[ RFC1925, 2.3 ]
Re: [patch V3 13/37] mips/mm/highmem: Switch to generic kmap atomic
On Fri, Jan 08, 2021 at 08:20:43PM +, Paul Cercueil wrote: > Hi Thomas, > > 5.11 does not boot anymore on Ingenic SoCs, I bisected it to this commit. > > Any idea what could be happening? not yet, kernel crash log of a Malta QEMU is below. Thomas. Kernel bug detected[#1]: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.11.0-rc1-00017-gccb21774863a #2 $ 0 : 0001 0010 $ 4 : 0001 05cf 9e00059f $ 8 : 00118173 809e6db8 9e00059f $12 : 82023c00 0001 810da04c 0212422f $16 : 810da000 00027800 05cf 80b4bf9c $20 : 809e968c 82602400 810da000 000b $24 : 021558f9 $28 : 820e 820e3928 80b1 802710d0 Hi: 346c Lo: 02dd epc : 80271114 __kmap_local_pfn_prot+0x78/0x1c0 ra: 802710d0 __kmap_local_pfn_prot+0x34/0x1c0 Status: 1000a403KERNEL EXL IE Cause : 00800034 (ExcCode 0d) PrId : 0001a800 (MIPS P5600) Modules linked in: Process swapper/0 (pid: 1, threadinfo=(ptrval), task=(ptrval), tls=) Stack : 7fff 820c2408 820e3990 ff04 0a00 80518224 81a4 810da000 0001 05cf fff64000 8011c77c 820e3b26 ff04 0a00 80518440 80b3 80b4bf64 9e0005cf 05cf fff64000 80271188 820e3a60 80b1 80194478 005e 80954406 809e 810da000 0001 05cf fff68000 8011c77c 8088fd44 809f6074 00f4 80b4bf68 ... Call Trace: [<80271114>] __kmap_local_pfn_prot+0x78/0x1c0 [<8011c77c>] __update_cache+0x16c/0x174 [<80271188>] __kmap_local_pfn_prot+0xec/0x1c0 [<8011c77c>] __update_cache+0x16c/0x174 [<80271188>] __kmap_local_pfn_prot+0xec/0x1c0 [<8011c77c>] __update_cache+0x16c/0x174 [<80271188>] __kmap_local_pfn_prot+0xec/0x1c0 [<8011c77c>] __update_cache+0x16c/0x174 [<80271188>] __kmap_local_pfn_prot+0xec/0x1c0 [<8011c77c>] __update_cache+0x16c/0x174 [<80271188>] __kmap_local_pfn_prot+0xec/0x1c0 [<8011c77c>] __update_cache+0x16c/0x174 [<80271188>] __kmap_local_pfn_prot+0xec/0x1c0 [<8011c77c>] __update_cache+0x16c/0x174 [<80271188>] __kmap_local_pfn_prot+0xec/0x1c0 [<8011c77c>] __update_cache+0x16c/0x174 [<80271188>] __kmap_local_pfn_prot+0xec/0x1c0 [<8011c77c>] __update_cache+0x16c/0x174 [<80271188>] __kmap_local_pfn_prot+0xec/0x1c0 [<8011c77c>] __update_cache+0x16c/0x174 [<80271188>] __kmap_local_pfn_prot+0xec/0x1c0 [<8011c77c>] __update_cache+0x16c/0x174 [<80271188>] __kmap_local_pfn_prot+0xec/0x1c0 [<8011c77c>] __update_cache+0x16c/0x174 [<80271188>] __kmap_local_pfn_prot+0xec/0x1c0 [<8011c77c>] __update_cache+0x16c/0x174 [<80271188>] __kmap_local_pfn_prot+0xec/0x1c0 [<8011c77c>] __update_cache+0x16c/0x174 [<80271188>] __kmap_local_pfn_prot+0xec/0x1c0 [<8011c77c>] __update_cache+0x16c/0x174 [<80271188>] __kmap_local_pfn_prot+0xec/0x1c0 [<802c49a0>] copy_string_kernel+0x168/0x264 [<802c5d18>] kernel_execve+0xd0/0x164 [<801006cc>] try_to_run_init_process+0x18/0x5c [<80859e0c>] kernel_init+0xd0/0x120 [<801037f8>] ret_from_kernel_thread+0x14/0x1c Code: 8c630564 28640010 38840001 <00040336> 8f82000c 2463 00021100 00431021 2403ffbf -- Crap can work. Given enough thrust pigs will fly, but it's not necessarily a good idea.[ RFC1925, 2.3 ]
Re: [patch V3 13/37] mips/mm/highmem: Switch to generic kmap atomic
Hi Thomas, 5.11 does not boot anymore on Ingenic SoCs, I bisected it to this commit. Any idea what could be happening? Cheers, -Paul
[patch V3 13/37] mips/mm/highmem: Switch to generic kmap atomic
No reason having the same code in every architecture
Signed-off-by: Thomas Gleixner
Cc: Thomas Bogendoerfer
Cc: linux-m...@vger.kernel.org
---
V3: Remove the kmap types cruft
---
arch/mips/Kconfig |1
arch/mips/include/asm/fixmap.h |4 -
arch/mips/include/asm/highmem.h|6 +-
arch/mips/include/asm/kmap_types.h | 13 --
arch/mips/mm/highmem.c | 77 -
arch/mips/mm/init.c|4 -
6 files changed, 6 insertions(+), 99 deletions(-)
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -2719,6 +2719,7 @@ config WAR_MIPS34K_MISSED_ITLB
config HIGHMEM
bool "High Memory Support"
depends on 32BIT && CPU_SUPPORTS_HIGHMEM && SYS_SUPPORTS_HIGHMEM &&
!CPU_MIPS32_3_5_EVA
+ select KMAP_LOCAL
config CPU_SUPPORTS_HIGHMEM
bool
--- a/arch/mips/include/asm/fixmap.h
+++ b/arch/mips/include/asm/fixmap.h
@@ -17,7 +17,7 @@
#include
#ifdef CONFIG_HIGHMEM
#include
-#include
+#include
#endif
/*
@@ -52,7 +52,7 @@ enum fixed_addresses {
#ifdef CONFIG_HIGHMEM
/* reserved pte's for temporary kernel mappings */
FIX_KMAP_BEGIN = FIX_CMAP_END + 1,
- FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
+ FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_MAX_IDX * NR_CPUS) - 1,
#endif
__end_of_fixed_addresses
};
--- a/arch/mips/include/asm/highmem.h
+++ b/arch/mips/include/asm/highmem.h
@@ -24,7 +24,7 @@
#include
#include
#include
-#include
+#include
/* declarations for highmem.c */
extern unsigned long highstart_pfn, highend_pfn;
@@ -48,11 +48,11 @@ extern pte_t *pkmap_page_table;
#define ARCH_HAS_KMAP_FLUSH_TLB
extern void kmap_flush_tlb(unsigned long addr);
-extern void *kmap_atomic_pfn(unsigned long pfn);
#define flush_cache_kmaps()BUG_ON(cpu_has_dc_aliases)
-extern void kmap_init(void);
+#define arch_kmap_local_post_map(vaddr, pteval)
local_flush_tlb_one(vaddr)
+#define arch_kmap_local_post_unmap(vaddr) local_flush_tlb_one(vaddr)
#endif /* __KERNEL__ */
--- a/arch/mips/include/asm/kmap_types.h
+++ /dev/null
@@ -1,13 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ASM_KMAP_TYPES_H
-#define _ASM_KMAP_TYPES_H
-
-#ifdef CONFIG_DEBUG_HIGHMEM
-#define __WITH_KM_FENCE
-#endif
-
-#include
-
-#undef __WITH_KM_FENCE
-
-#endif
--- a/arch/mips/mm/highmem.c
+++ b/arch/mips/mm/highmem.c
@@ -8,8 +8,6 @@
#include
#include
-static pte_t *kmap_pte;
-
unsigned long highstart_pfn, highend_pfn;
void kmap_flush_tlb(unsigned long addr)
@@ -17,78 +15,3 @@ void kmap_flush_tlb(unsigned long addr)
flush_tlb_one(addr);
}
EXPORT_SYMBOL(kmap_flush_tlb);
-
-void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
-{
- unsigned long vaddr;
- int idx, type;
-
- type = kmap_atomic_idx_push();
- idx = type + KM_TYPE_NR*smp_processor_id();
- vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
-#ifdef CONFIG_DEBUG_HIGHMEM
- BUG_ON(!pte_none(*(kmap_pte - idx)));
-#endif
- set_pte(kmap_pte-idx, mk_pte(page, prot));
- local_flush_tlb_one((unsigned long)vaddr);
-
- return (void*) vaddr;
-}
-EXPORT_SYMBOL(kmap_atomic_high_prot);
-
-void kunmap_atomic_high(void *kvaddr)
-{
- unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
- int type __maybe_unused;
-
- if (vaddr < FIXADDR_START)
- return;
-
- type = kmap_atomic_idx();
-#ifdef CONFIG_DEBUG_HIGHMEM
- {
- int idx = type + KM_TYPE_NR * smp_processor_id();
-
- BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
-
- /*
-* force other mappings to Oops if they'll try to access
-* this pte without first remap it
-*/
- pte_clear(&init_mm, vaddr, kmap_pte-idx);
- local_flush_tlb_one(vaddr);
- }
-#endif
- kmap_atomic_idx_pop();
-}
-EXPORT_SYMBOL(kunmap_atomic_high);
-
-/*
- * This is the same as kmap_atomic() but can map memory that doesn't
- * have a struct page associated with it.
- */
-void *kmap_atomic_pfn(unsigned long pfn)
-{
- unsigned long vaddr;
- int idx, type;
-
- preempt_disable();
- pagefault_disable();
-
- type = kmap_atomic_idx_push();
- idx = type + KM_TYPE_NR*smp_processor_id();
- vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
- set_pte(kmap_pte-idx, pfn_pte(pfn, PAGE_KERNEL));
- flush_tlb_one(vaddr);
-
- return (void*) vaddr;
-}
-
-void __init kmap_init(void)
-{
- unsigned long kmap_vstart;
-
- /* cache the first kmap pte */
- kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
- kmap_pte = virt_to_kpte(kmap_vstart);
-}
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c
@@ -36,7 +36,6 @@
#include
#include
#include
-#include
#include
#include
#include
@@ -402,9 +401,6 @@ void __init paging_init(void)
pagetable_init();
-#ifdef CONFIG
