From mboxrd@z Thu Jan 1 00:00:00 1970 From: catalin.marinas@arm.com (Catalin Marinas) Date: Wed, 12 Mar 2014 16:03:40 +0000 Subject: [PATCH] ARM64: Kernel managed pages are only flushed In-Reply-To: <20140312145653.GA9691@mudshark.cambridge.arm.com> References: <1394018446-16738-1-git-send-email-Bharat.Bhushan@freescale.com> <20140306065339.GA2975@localhost> <20140312145653.GA9691@mudshark.cambridge.arm.com> Message-ID: <20140312160340.GI17083@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, Mar 12, 2014 at 02:56:53PM +0000, Will Deacon wrote: > On Wed, Mar 12, 2014 at 02:41:31PM +0000, Bharat.Bhushan at freescale.com wrote: > > Did you get the chance to look into this? What is your take for this patch > > or you want to suggest some other solution? > > See my reply to Laura here: > > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-March/238510.html > > We *really* don't want executable device mappings. /dev/mem mapping use pgprot_noncached() but I think we could generalise any of the writecombine and dmacoherent mappings to XN like in the patch below: diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index b524dcd17243..2d3cede62709 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -286,11 +286,11 @@ static inline int has_transparent_hugepage(void) * Mark the prot value as uncacheable and unbufferable. */ #define pgprot_noncached(prot) \ - __pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_DEVICE_nGnRnE)) + __pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_DEVICE_nGnRnE) | PTE_PXN | PTE_UXN) #define pgprot_writecombine(prot) \ - __pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_NORMAL_NC)) + __pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_NORMAL_NC) | PTE_PXN | PTE_UXN) #define pgprot_dmacoherent(prot) \ - __pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_NORMAL_NC)) + __pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_NORMAL_NC) | PTE_PXN | PTE_UXN) #define __HAVE_PHYS_MEM_ACCESS_PROT struct file; extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, -- Catalin