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| author | Will Deacon <will.deacon@arm.com> | 2012-08-10 16:51:18 (GMT) |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2012-08-11 08:15:59 (GMT) |
| commit | 47f1204329237a0f8655f5a9f14a38ac81946ca1 (patch) | |
| tree | 863782a6d372973865860a3e55d79a0cbd01880d /arch/arm | |
| parent | 237ec6f2e51d2fc2ff37c7c5f1ccc9264d09c85b (diff) | |
| download | linux-47f1204329237a0f8655f5a9f14a38ac81946ca1.tar.xz | |
ARM: 7487/1: mm: avoid setting nG bit for user mappings that aren't present
Swap entries are encoding in ptes such that !pte_present(pte) and
pte_file(pte). The remaining bits of the descriptor are used to identify
the swapfile and offset within it to the swap entry.
When writing such a pte for a user virtual address, set_pte_at
unconditionally sets the nG bit, which (in the case of LPAE) will
corrupt the swapfile offset and lead to a BUG:
[ 140.494067] swap_free: Unused swap offset entry 000763b4
[ 140.509989] BUG: Bad page map in process rs:main Q:Reg pte:0ec76800 pmd:8f92e003
This patch fixes the problem by only setting the nG bit for user
mappings that are actually present.
Cc: <stable@vger.kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/include/asm/pgtable.h | 34 | ||||
| -rw-r--r-- | arch/arm/mm/flush.c | 2 |
2 files changed, 18 insertions, 18 deletions
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h index f66626d..d88f9f0 100644 --- a/arch/arm/include/asm/pgtable.h +++ b/arch/arm/include/asm/pgtable.h @@ -195,6 +195,18 @@ static inline pte_t *pmd_page_vaddr(pmd_t pmd) #define pte_clear(mm,addr,ptep) set_pte_ext(ptep, __pte(0), 0) +#define pte_none(pte) (!pte_val(pte)) +#define pte_present(pte) (pte_val(pte) & L_PTE_PRESENT) +#define pte_write(pte) (!(pte_val(pte) & L_PTE_RDONLY)) +#define pte_dirty(pte) (pte_val(pte) & L_PTE_DIRTY) +#define pte_young(pte) (pte_val(pte) & L_PTE_YOUNG) +#define pte_exec(pte) (!(pte_val(pte) & L_PTE_XN)) +#define pte_special(pte) (0) + +#define pte_present_user(pte) \ + ((pte_val(pte) & (L_PTE_PRESENT | L_PTE_USER)) == \ + (L_PTE_PRESENT | L_PTE_USER)) + #if __LINUX_ARM_ARCH__ < 6 static inline void __sync_icache_dcache(pte_t pteval) { @@ -206,25 +218,15 @@ extern void __sync_icache_dcache(pte_t pteval); static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pteval) { - if (addr >= TASK_SIZE) - set_pte_ext(ptep, pteval, 0); - else { + unsigned long ext = 0; + + if (addr < TASK_SIZE && pte_present_user(pteval)) { __sync_icache_dcache(pteval); - set_pte_ext(ptep, pteval, PTE_EXT_NG); + ext |= PTE_EXT_NG; } -} -#define pte_none(pte) (!pte_val(pte)) -#define pte_present(pte) (pte_val(pte) & L_PTE_PRESENT) -#define pte_write(pte) (!(pte_val(pte) & L_PTE_RDONLY)) -#define pte_dirty(pte) (pte_val(pte) & L_PTE_DIRTY) -#define pte_young(pte) (pte_val(pte) & L_PTE_YOUNG) -#define pte_exec(pte) (!(pte_val(pte) & L_PTE_XN)) -#define pte_special(pte) (0) - -#define pte_present_user(pte) \ - ((pte_val(pte) & (L_PTE_PRESENT | L_PTE_USER)) == \ - (L_PTE_PRESENT | L_PTE_USER)) + set_pte_ext(ptep, pteval, ext); +} #define PTE_BIT_FUNC(fn,op) \ static inline pte_t pte_##fn(pte_t pte) { pte_val(pte) op; return pte; } diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c index 7745854..40ca11e 100644 --- a/arch/arm/mm/flush.c +++ b/arch/arm/mm/flush.c @@ -231,8 +231,6 @@ void __sync_icache_dcache(pte_t pteval) struct page *page; struct address_space *mapping; - if (!pte_present_user(pteval)) - return; if (cache_is_vipt_nonaliasing() && !pte_exec(pteval)) /* only flush non-aliasing VIPT caches for exec mappings */ return; |