From: Zachary Amsden Date: Thu, 7 Dec 2006 01:14:09 +0000 (+0100) Subject: [PATCH] paravirt: fix missing pte update X-Git-Tag: v2.6.20-rc1~145^2^2~8^2~65 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8ecb8950695e907ed25acffec9e98c6806e311c8;p=linux-2.6 [PATCH] paravirt: fix missing pte update The function ptep_get_and_clear uses an atomic instruction sequence to get and clear an active pte. Rather than add such an atomic operator to all virtual machine implementations in paravirt-ops, it is easier to support the raw atomic sequence and use either a trapping writable pagetable approach, or a post-update notification. For the post update notification, we require the pte_update function to be called after the access. Combine the 2-level and 3-level paging operators into one common function which does the post-update notification, and rename the actual atomic sequences to raw_ptep_xxx operators. Signed-off-by: Zachary Amsden Signed-off-by: Andi Kleen Cc: Andi Kleen Cc: Jeremy Fitzhardinge Cc: Chris Wright Signed-off-by: Andrew Morton --- diff --git a/include/asm-i386/pgtable-2level.h b/include/asm-i386/pgtable-2level.h index c08cbc4c2d..38c3fcc067 100644 --- a/include/asm-i386/pgtable-2level.h +++ b/include/asm-i386/pgtable-2level.h @@ -23,8 +23,7 @@ #define pte_clear(mm,addr,xp) do { set_pte_at(mm, addr, xp, __pte(0)); } while (0) #define pmd_clear(xp) do { set_pmd(xp, __pmd(0)); } while (0) -#define __HAVE_ARCH_PTEP_GET_AND_CLEAR -#define ptep_get_and_clear(mm,addr,xp) __pte(xchg(&(xp)->pte_low, 0)) +#define raw_ptep_get_and_clear(xp) __pte(xchg(&(xp)->pte_low, 0)) #define pte_page(x) pfn_to_page(pte_pfn(x)) #define pte_none(x) (!(x).pte_low) diff --git a/include/asm-i386/pgtable-3level.h b/include/asm-i386/pgtable-3level.h index 54287f148c..7a2318f383 100644 --- a/include/asm-i386/pgtable-3level.h +++ b/include/asm-i386/pgtable-3level.h @@ -119,8 +119,7 @@ static inline void pud_clear (pud_t * pud) { } #define pmd_offset(pud, address) ((pmd_t *) pud_page(*(pud)) + \ pmd_index(address)) -#define __HAVE_ARCH_PTEP_GET_AND_CLEAR -static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) +static inline pte_t raw_ptep_get_and_clear(pte_t *ptep) { pte_t res; diff --git a/include/asm-i386/pgtable.h b/include/asm-i386/pgtable.h index 04dd39b973..b4a301f647 100644 --- a/include/asm-i386/pgtable.h +++ b/include/asm-i386/pgtable.h @@ -326,6 +326,14 @@ do { \ __young; \ }) +#define __HAVE_ARCH_PTEP_GET_AND_CLEAR +static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) +{ + pte_t pte = raw_ptep_get_and_clear(ptep); + pte_update(mm, addr, ptep); + return pte; +} + #define __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm, unsigned long addr, pte_t *ptep, int full) {