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Date: Tue, 10 Nov 2015 17:57:36 -0800 From: Laura Abbott <labbott@...oraproject.org> To: Catalin Marinas <catalin.marinas@....com>, Will Deacon <will.deacon@....com>, Ard Biesheuvel <ard.biesheuvel@...aro.org>, Zhong Jiang <zhongjiang@...wei.com> Cc: Laura Abbott <labbott@...oraproject.org>, linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, Kees Cook <keescook@...omium.org>, Xishi Qiu <qiuxishi@...wei.com>, Mark Rutland <mark.rutland@....com> Subject: [PATCHv2 1/2] arm64: Get existing page protections in split_pmd Rather than always putting the least restrictived permissions (PAGE_KERNEL_EXEC) when spliting a pmd into pages, use the existing permissions from the pmd for the page. Signed-off-by: Laura Abbott <labbott@...oraproject.org> --- v2: Typo and typechecking fixed I chose not to add the Reviewed-by from Ard here because of the addition of the contiguous bit in split_pmd. Not sure if I should be explicitly carrying it over. --- arch/arm64/mm/mmu.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index c2fa6b5..496c3fd 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -76,15 +76,13 @@ static void __init *early_alloc(unsigned long sz) static void split_pmd(pmd_t *pmd, pte_t *pte) { unsigned long pfn = pmd_pfn(*pmd); + unsigned long addr = pfn << PAGE_SHIFT; + pgprot_t prot = __pgprot((pmd_val(*pmd) ^ addr) | PTE_TYPE_PAGE); + int i = 0; do { - /* - * Need to have the least restrictive permissions available - * permissions will be fixed up later. Default the new page - * range as contiguous ptes. - */ - set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC_CONT)); + set_pte(pte, pfn_pte(pfn, prot)); pfn++; } while (pte++, i++, i < PTRS_PER_PTE); } -- 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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