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| author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2010-07-23 08:53:23 +1000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2010-07-23 08:53:23 +1000 |
| commit | ca91e6c09d656c6deb1f2bc5d57186c718106aa5 (patch) | |
| tree | a8d30759b6fac5616691b7a4a94222ab371d2bd6 /arch/powerpc/mm/hash_utils_64.c | |
| parent | b1623e7eb280f853f60338c7bb68bd3f3a970205 (diff) | |
| download | linux-ca91e6c09d656c6deb1f2bc5d57186c718106aa5.tar.bz2 | |
powerpc/mm: Move around testing of _PAGE_PRESENT in hash code
Instead of adding _PAGE_PRESENT to the access permission mask
in each low level routine independently, we add it once from
hash_page().
We also move the preliminary access check (the racy one before
the PTE is locked) up so it applies to the huge page case. This
duplicates code in __hash_page_huge() which we'll remove in a
subsequent patch to fix a race in there.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/mm/hash_utils_64.c')
| -rw-r--r-- | arch/powerpc/mm/hash_utils_64.c | 19 |
1 files changed, 11 insertions, 8 deletions
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c index 98f262de5585..40847a9dd6db 100644 --- a/arch/powerpc/mm/hash_utils_64.c +++ b/arch/powerpc/mm/hash_utils_64.c @@ -955,6 +955,17 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap) return 1; } + /* Add _PAGE_PRESENT to the required access perm */ + access |= _PAGE_PRESENT; + + /* Pre-check access permissions (will be re-checked atomically + * in __hash_page_XX but this pre-check is a fast path + */ + if (access & ~pte_val(*ptep)) { + DBG_LOW(" no access !\n"); + return 1; + } + #ifdef CONFIG_HUGETLB_PAGE if (hugeshift) return __hash_page_huge(ea, access, vsid, ptep, trap, local, @@ -967,14 +978,6 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap) DBG_LOW(" i-pte: %016lx %016lx\n", pte_val(*ptep), pte_val(*(ptep + PTRS_PER_PTE))); #endif - /* Pre-check access permissions (will be re-checked atomically - * in __hash_page_XX but this pre-check is a fast path - */ - if (access & ~pte_val(*ptep)) { - DBG_LOW(" no access !\n"); - return 1; - } - /* Do actual hashing */ #ifdef CONFIG_PPC_64K_PAGES /* If _PAGE_4K_PFN is set, make sure this is a 4k segment */ |