[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 <zach@vmware.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@muc.de>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
This commit is contained in:
Zachary Amsden 2006-12-07 02:14:09 +01:00 committed by Andi Kleen
parent dfbea0ad50
commit 8ecb895069
3 changed files with 10 additions and 4 deletions

View file

@ -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)

View file

@ -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;

View file

@ -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)
{