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| author | Will Deacon <will.deacon@arm.com> | 2012-08-10 17:51:18 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-09-14 10:00:36 -0700 |
| commit | 9a0417a2d4b082bede8c0495d14d8bb20afaa700 (patch) | |
| tree | 283aad49cbeaf79cbfcd021fb7a1417cf7f7a1f2 /arch/arm/include/asm/pgtable.h | |
| parent | 33fe660ca2679c4d0234a49cffb82001a57ab003 (diff) | |
| download | lwn-9a0417a2d4b082bede8c0495d14d8bb20afaa700.tar.gz lwn-9a0417a2d4b082bede8c0495d14d8bb20afaa700.zip | |
ARM: 7487/1: mm: avoid setting nG bit for user mappings that aren't present
commit 47f1204329237a0f8655f5a9f14a38ac81946ca1 upstream.
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.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/arm/include/asm/pgtable.h')
| -rw-r--r-- | arch/arm/include/asm/pgtable.h | 34 |
1 files changed, 18 insertions, 16 deletions
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h index 5750704e0271..4c477044c47a 100644 --- a/arch/arm/include/asm/pgtable.h +++ b/arch/arm/include/asm/pgtable.h @@ -360,6 +360,18 @@ static inline pte_t *pmd_page_vaddr(pmd_t pmd) #define set_pte_ext(ptep,pte,ext) cpu_set_pte_ext(ptep,pte,ext) #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) { @@ -371,25 +383,15 @@ 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; } |