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Date: Sun, 15 Nov 2015 08:38:25 +0100 From: Ard Biesheuvel <ard.biesheuvel@...aro.org> To: Laura Abbott <labbott@...oraproject.org> Cc: Catalin Marinas <catalin.marinas@....com>, Will Deacon <will.deacon@....com>, "linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org> Subject: Re: [PATCHv2] arm64: Fix R/O permissions in mark_rodata_ro On 12 November 2015 at 21:21, Laura Abbott <labbott@...oraproject.org> wrote: > The permissions in mark_rodata_ro trigger a build error > with STRICT_MM_TYPECHECKS. Fix this by introducing > PAGE_KERNEL_ROX for the same reasons as PAGE_KERNEL_RO. Forgive the bikeshedding but perhaps PAGE_KERNEL_EXEC_RO is more consistent? > From Ard: > > "PAGE_KERNEL_EXEC has PTE_WRITE set as well, making the range > writeable under the ARMv8.1 DBM feature, that manages the > dirty bit in hardware (writing to a page with the PTE_RDONLY > and PTE_WRITE bits both set will clear the PTE_RDONLY bit in that case)" > > Signed-off-by: Laura Abbott <labbott@...oraproject.org> Acked-by: Ard Biesheuvel <ard.biesheuvel@...aro.org> > --- > arch/arm64/include/asm/pgtable.h | 1 + > arch/arm64/mm/mmu.c | 2 +- > 2 files changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index 9819a94..7e074f9 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -81,6 +81,7 @@ extern void __pgd_error(const char *file, int line, unsigned long val); > > #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_ROX __pgprot(_PAGE_DEFAULT | 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 9ca5996..6598c48 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -475,7 +475,7 @@ void mark_rodata_ro(void) > { > create_mapping_late(__pa(_stext), (unsigned long)_stext, > (unsigned long)_etext - (unsigned long)_stext, > - PAGE_KERNEL_EXEC | PTE_RDONLY); > + PAGE_KERNEL_ROX); > > } > #endif > -- > 2.5.0 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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