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| 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 /include/asm-i386 | |
| parent | a5bfffac645a7b2d8119f8bbae34df5c94832799 (diff) | |
| download | lwn-49f19710512c825aaea73b9207b3a848027cda1d.tar.gz lwn-49f19710512c825aaea73b9207b3a848027cda1d.zip | |
[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 'include/asm-i386')
| -rw-r--r-- | include/asm-i386/paravirt.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/asm-i386/paravirt.h b/include/asm-i386/paravirt.h index 46dc34ca887a..e63f1e444fcf 100644 --- a/include/asm-i386/paravirt.h +++ b/include/asm-i386/paravirt.h @@ -421,14 +421,17 @@ static inline void pmd_clear(pmd_t *pmdp) #define PARAVIRT_LAZY_NONE 0 #define PARAVIRT_LAZY_MMU 1 #define PARAVIRT_LAZY_CPU 2 +#define PARAVIRT_LAZY_FLUSH 3 #define __HAVE_ARCH_ENTER_LAZY_CPU_MODE #define arch_enter_lazy_cpu_mode() paravirt_ops.set_lazy_mode(PARAVIRT_LAZY_CPU) #define arch_leave_lazy_cpu_mode() paravirt_ops.set_lazy_mode(PARAVIRT_LAZY_NONE) +#define arch_flush_lazy_cpu_mode() paravirt_ops.set_lazy_mode(PARAVIRT_LAZY_FLUSH) #define __HAVE_ARCH_ENTER_LAZY_MMU_MODE #define arch_enter_lazy_mmu_mode() paravirt_ops.set_lazy_mode(PARAVIRT_LAZY_MMU) #define arch_leave_lazy_mmu_mode() paravirt_ops.set_lazy_mode(PARAVIRT_LAZY_NONE) +#define arch_flush_lazy_mmu_mode() paravirt_ops.set_lazy_mode(PARAVIRT_LAZY_FLUSH) /* These all sit in the .parainstructions section to tell us what to patch. */ struct paravirt_patch { |