diff options
| author | Andy Whitcroft <apw@shadowen.org> | 2008-06-26 19:55:58 +1000 |
|---|---|---|
| committer | Paul Mackerras <paulus@samba.org> | 2008-07-01 11:28:56 +1000 |
| commit | 016b33c4958681c24056abed8ec95844a0da80a3 (patch) | |
| tree | 67ba81cb6bc980119fab4eee15f09488e5777012 | |
| parent | 03d70617b8a789c3721afaafde06fcbba7c7ebf1 (diff) | |
powerpc: Add 64 bit version of huge_ptep_set_wrprotect
The implementation of huge_ptep_set_wrprotect() directly calls
ptep_set_wrprotect() to mark a hugepte write protected. However this
call is not appropriate on ppc64 kernels as this is a small page only
implementation. This can lead to the hash not being flushed correctly
when a mapping is being converted to COW, allowing processes to continue
using the original copy.
Currently huge_ptep_set_wrprotect() unconditionally calls
ptep_set_wrprotect(). This is fine on ppc32 kernels as this call is
generic. On 64 bit this is implemented as:
pte_update(mm, addr, ptep, _PAGE_RW, 0);
On ppc64 this last parameter is the page size and is passed directly on
to hpte_need_flush():
hpte_need_flush(mm, addr, ptep, old, huge);
And this directly affects the page size we pass to flush_hash_page():
flush_hash_page(vaddr, rpte, psize, ssize, 0);
As this changes the way the hash is calculated we will flush the wrong
pages, potentially leaving live hashes to the original page.
Move the definition of huge_ptep_set_wrprotect() to the 32/64 bit specific
headers.
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
| -rw-r--r-- | include/asm-powerpc/hugetlb.h | 6 | ||||
| -rw-r--r-- | include/asm-powerpc/pgtable-ppc32.h | 6 | ||||
| -rw-r--r-- | include/asm-powerpc/pgtable-ppc64.h | 9 |
3 files changed, 15 insertions, 6 deletions
diff --git a/include/asm-powerpc/hugetlb.h b/include/asm-powerpc/hugetlb.h index 649c6c3b87b..be32ff02f4a 100644 --- a/include/asm-powerpc/hugetlb.h +++ b/include/asm-powerpc/hugetlb.h @@ -49,12 +49,6 @@ static inline pte_t huge_pte_wrprotect(pte_t pte) return pte_wrprotect(pte); } -static inline void huge_ptep_set_wrprotect(struct mm_struct *mm, - unsigned long addr, pte_t *ptep) -{ - ptep_set_wrprotect(mm, addr, ptep); -} - static inline int huge_ptep_set_access_flags(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep, pte_t pte, int dirty) diff --git a/include/asm-powerpc/pgtable-ppc32.h b/include/asm-powerpc/pgtable-ppc32.h index dde466bd2ce..e1d2bb57f1d 100644 --- a/include/asm-powerpc/pgtable-ppc32.h +++ b/include/asm-powerpc/pgtable-ppc32.h @@ -652,6 +652,12 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, { pte_update(ptep, (_PAGE_RW | _PAGE_HWWRITE), 0); } +static inline void huge_ptep_set_wrprotect(struct mm_struct *mm, + unsigned long addr, pte_t *ptep) +{ + ptep_set_wrprotect(mm, addr, ptep); +} + #define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS static inline void __ptep_set_access_flags(pte_t *ptep, pte_t entry, int dirty) diff --git a/include/asm-powerpc/pgtable-ppc64.h b/include/asm-powerpc/pgtable-ppc64.h index 2e48be841cc..b2754d46be4 100644 --- a/include/asm-powerpc/pgtable-ppc64.h +++ b/include/asm-powerpc/pgtable-ppc64.h @@ -312,6 +312,15 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, return; old = pte_update(mm, addr, ptep, _PAGE_RW, 0); } +static inline void huge_ptep_set_wrprotect(struct mm_struct *mm, + unsigned long addr, pte_t *ptep) +{ + unsigned long old; + + if ((pte_val(*ptep) & _PAGE_RW) == 0) + return; + old = pte_update(mm, addr, ptep, _PAGE_RW, 1); +} /* * We currently remove entries from the hashtable regardless of whether |