diff options
| author | Zachary Amsden <zach@vmware.com> | 2007-04-08 16:04:01 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-04-08 19:47:55 -0700 |
| commit | 49f19710512c825aaea73b9207b3a848027cda1d (patch) | |
| tree | 06da31bd9a84273e12aa43f536f90eb8146ff92e /arch/i386/mm | |
| parent | a5bfffac645a7b2d8119f8bbae34df5c94832799 (diff) | |
[PATCH] Proper fix for highmem kmap_atomic functions for VMI for 2.6.21
Since lazy MMU batching mode still allows interrupts to enter, it is
possible for interrupt handlers to try to use kmap_atomic, which fails when
lazy mode is active, since the PTE update to highmem will be delayed. The
best workaround is to issue an explicit flush in kmap_atomic_functions
case; this is the only way nested PTE updates can happen in the interrupt
handler.
Thanks to Jeremy Fitzhardinge for noting the bug and suggestions on a fix.
This patch gets reverted again when we start 2.6.22 and the bug gets fixed
differently.
Signed-off-by: Zachary Amsden <zach@vmware.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/i386/mm')
| -rw-r--r-- | arch/i386/mm/highmem.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/i386/mm/highmem.c b/arch/i386/mm/highmem.c index bb2de1089ad..ac70d09df7e 100644 --- a/arch/i386/mm/highmem.c +++ b/arch/i386/mm/highmem.c @@ -42,6 +42,7 @@ void *kmap_atomic(struct page *page, enum km_type type) vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); set_pte(kmap_pte-idx, mk_pte(page, kmap_prot)); + arch_flush_lazy_mmu_mode(); return (void*) vaddr; } @@ -82,6 +83,7 @@ void *kmap_atomic_pfn(unsigned long pfn, enum km_type type) idx = type + KM_TYPE_NR*smp_processor_id(); vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); set_pte(kmap_pte-idx, pfn_pte(pfn, kmap_prot)); + arch_flush_lazy_mmu_mode(); return (void*) vaddr; } |