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| author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2015-11-09 11:55:46 +0300 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2015-11-09 17:26:36 +0300 |
| commit | fb226c3d7c77b4f99cee675795cc0e70937c56ee (patch) | |
| tree | 08f88c1b14952e03fdf797f0ec233923463cfa56 /arch/arm64 | |
| parent | b219545e9646e9d4089a74029c82ae59645e12ae (diff) | |
| download | linux-fb226c3d7c77b4f99cee675795cc0e70937c56ee.tar.xz | |
arm64: fix R/O permissions of FDT mapping
The mapping permissions of the FDT are set to 'PAGE_KERNEL | PTE_RDONLY'
in an attempt to map the FDT as read-only. However, not only does this
break at build time under STRICT_MM_TYPECHECKS (since the two terms are
of different types in that case), it also results in both the PTE_WRITE
and PTE_RDONLY attributes to be set, which means the region is still
writable under ARMv8.1 DBM (and an attempted write will simply clear the
PT_RDONLY bit).
So instead, define PAGE_KERNEL_RO (which already has an established
meaning across architectures) and use that instead.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64')
| -rw-r--r-- | arch/arm64/include/asm/pgtable.h | 1 | ||||
| -rw-r--r-- | arch/arm64/mm/mmu.c | 2 |
2 files changed, 2 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index c3d22a507648..1c99d5610bc7 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -78,6 +78,7 @@ extern void __pgd_error(const char *file, int line, unsigned long val); #define _PAGE_DEFAULT (PROT_DEFAULT | PTE_ATTRINDX(MT_NORMAL)) #define PAGE_KERNEL __pgprot(_PAGE_DEFAULT | PTE_PXN | PTE_UXN | PTE_DIRTY | PTE_WRITE) +#define PAGE_KERNEL_RO __pgprot(_PAGE_DEFAULT | PTE_PXN | PTE_UXN | PTE_DIRTY | PTE_RDONLY) #define PAGE_KERNEL_EXEC __pgprot(_PAGE_DEFAULT | PTE_UXN | PTE_DIRTY | PTE_WRITE) #define PAGE_KERNEL_EXEC_CONT __pgprot(_PAGE_DEFAULT | PTE_UXN | PTE_DIRTY | PTE_WRITE | PTE_CONT) diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 2784f052df5e..5e23de53b747 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -691,7 +691,7 @@ void __set_fixmap(enum fixed_addresses idx, void *__init fixmap_remap_fdt(phys_addr_t dt_phys) { const u64 dt_virt_base = __fix_to_virt(FIX_FDT); - pgprot_t prot = PAGE_KERNEL | PTE_RDONLY; + pgprot_t prot = PAGE_KERNEL_RO; int size, offset; void *dt_virt; |