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authorZachary Amsden <zach@vmware.com>2007-04-08 16:04:01 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-04-08 19:47:55 -0700
commit49f19710512c825aaea73b9207b3a848027cda1d (patch)
tree06da31bd9a84273e12aa43f536f90eb8146ff92e /include/asm-i386
parenta5bfffac645a7b2d8119f8bbae34df5c94832799 (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 'include/asm-i386')
-rw-r--r--include/asm-i386/paravirt.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/include/asm-i386/paravirt.h b/include/asm-i386/paravirt.h
index 46dc34ca887..e63f1e444fc 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 {