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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2015-11-09 11:55:46 +0300
committerCatalin Marinas <catalin.marinas@arm.com>2015-11-09 17:26:36 +0300
commitfb226c3d7c77b4f99cee675795cc0e70937c56ee (patch)
tree08f88c1b14952e03fdf797f0ec233923463cfa56 /arch/arm64
parentb219545e9646e9d4089a74029c82ae59645e12ae (diff)
downloadlinux-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.h1
-rw-r--r--arch/arm64/mm/mmu.c2
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;