From 49f19710512c825aaea73b9207b3a848027cda1d Mon Sep 17 00:00:00 2001 From: Zachary Amsden Date: Sun, 8 Apr 2007 16:04:01 -0700 Subject: [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 Cc: Andi Kleen Cc: Jeremy Fitzhardinge Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/asm-i386/paravirt.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/asm-i386/paravirt.h') 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 { -- cgit v1.2.3-59-g8ed1b