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| author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2018-02-23 21:04:48 +0300 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2018-02-26 17:27:14 +0300 |
| commit | 753e8abc36b2c966caea075db0c845563c8a19bf (patch) | |
| tree | 8a507c29bc0b2da625692d8e1bbe0f396be0c8a7 /arch/arm64/mm/mmu.c | |
| parent | 4a3928c6f8a53fa1aed28ccba227742486e8ddcb (diff) | |
| download | linux-753e8abc36b2c966caea075db0c845563c8a19bf.tar.xz | |
arm64: mm: fix thinko in non-global page table attribute check
The routine pgattr_change_is_safe() was extended in commit 4e6020565596
("arm64: mm: Permit transitioning from Global to Non-Global without BBM")
to permit changing the nG attribute from not set to set, but did so in a
way that inadvertently disallows such changes if other permitted attribute
changes take place at the same time. So update the code to take this into
account.
Fixes: 4e6020565596 ("arm64: mm: Permit transitioning from Global to ...")
Cc: <stable@vger.kernel.org> # 4.14.x-
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/mm/mmu.c')
| -rw-r--r-- | arch/arm64/mm/mmu.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 84a019f55022..8c704f1e53c2 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -108,7 +108,7 @@ static bool pgattr_change_is_safe(u64 old, u64 new) * The following mapping attributes may be updated in live * kernel mappings without the need for break-before-make. */ - static const pteval_t mask = PTE_PXN | PTE_RDONLY | PTE_WRITE; + static const pteval_t mask = PTE_PXN | PTE_RDONLY | PTE_WRITE | PTE_NG; /* creating or taking down mappings is always safe */ if (old == 0 || new == 0) @@ -118,9 +118,9 @@ static bool pgattr_change_is_safe(u64 old, u64 new) if ((old | new) & PTE_CONT) return false; - /* Transitioning from Global to Non-Global is safe */ - if (((old ^ new) == PTE_NG) && (new & PTE_NG)) - return true; + /* Transitioning from Non-Global to Global is unsafe */ + if (old & ~new & PTE_NG) + return false; return ((old ^ new) & ~mask) == 0; } |