From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ard Biesheuvel Subject: [PATCH 1/2] arm64/efi: base UEFI mapping permissions on region attributes Date: Tue, 30 Jun 2015 12:17:22 +0200 Message-ID: <1435659443-17625-2-git-send-email-ard.biesheuvel@linaro.org> References: <1435659443-17625-1-git-send-email-ard.biesheuvel@linaro.org> Return-path: In-Reply-To: <1435659443-17625-1-git-send-email-ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, matt.fleming-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org Cc: leif.lindholm-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, roy.franz-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, msalter-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, lersek-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, Ard Biesheuvel List-Id: linux-efi@vger.kernel.org Currently, we infer the UEFI memory region mapping permissions from the memory region type (i.e., runtime services code are mapped RWX and runtime services data mapped RW-). This appears to work fine but is not entirely UEFI spec compliant. So instead, use the designated permission attributes to decide how these regions should be mapped. Since UEFIv2.5 introduces a new EFI_MEMORY_RO permission attribute, and redefines EFI_MEMORY_WP as a cacheability attribute, use only the former as a read-only attribute. For setting the PXN bit, the corresponding EFI_MEMORY_XP attribute is used. Signed-off-by: Ard Biesheuvel --- arch/arm64/kernel/efi.c | 32 +++++++++++++------- 1 file changed, 21 insertions(+), 11 deletions(-) diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c index ab21e0d58278..5dcab58d5d30 100644 --- a/arch/arm64/kernel/efi.c +++ b/arch/arm64/kernel/efi.c @@ -247,20 +247,30 @@ static bool __init efi_virtmap_init(void) memrange_efi_to_native(&paddr, &npages); size = npages << PAGE_SHIFT; - pr_info(" EFI remap 0x%016llx => %p\n", - md->phys_addr, (void *)md->virt_addr); - - /* - * Only regions of type EFI_RUNTIME_SERVICES_CODE need to be - * executable, everything else can be mapped with the XN bits - * set. - */ if (!is_normal_ram(md)) prot = __pgprot(PROT_DEVICE_nGnRE); - else if (md->type == EFI_RUNTIME_SERVICES_CODE) - prot = PAGE_KERNEL_EXEC; else - prot = PAGE_KERNEL; + prot = PAGE_KERNEL_EXEC; + + /* + * On 64 KB granule kernels, only use strict permissions when + * the region does not share a 64 KB page frame with another + * region at either end. + */ + if (!IS_ENABLED(CONFIG_ARM64_64K_PAGES) || + !(md->virt_addr % PAGE_SIZE || + (md->phys_addr + md->num_pages * EFI_PAGE_SIZE) % PAGE_SIZE)) { + + if (md->attribute & EFI_MEMORY_RO) + prot |= __pgprot(PTE_RDONLY); + if (md->attribute & EFI_MEMORY_XP) + prot |= __pgprot(PTE_PXN); + } + + pr_info(" EFI remap 0x%016llx => %p (R%c%c)\n", + md->phys_addr, (void *)md->virt_addr, + prot & __pgprot(PTE_RDONLY) ? '-' : 'W', + prot & __pgprot(PTE_PXN) ? '-' : 'X'); create_pgd_mapping(&efi_mm, paddr, md->virt_addr, size, prot); } -- 1.9.1 From mboxrd@z Thu Jan 1 00:00:00 1970 From: ard.biesheuvel@linaro.org (Ard Biesheuvel) Date: Tue, 30 Jun 2015 12:17:22 +0200 Subject: [PATCH 1/2] arm64/efi: base UEFI mapping permissions on region attributes In-Reply-To: <1435659443-17625-1-git-send-email-ard.biesheuvel@linaro.org> References: <1435659443-17625-1-git-send-email-ard.biesheuvel@linaro.org> Message-ID: <1435659443-17625-2-git-send-email-ard.biesheuvel@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Currently, we infer the UEFI memory region mapping permissions from the memory region type (i.e., runtime services code are mapped RWX and runtime services data mapped RW-). This appears to work fine but is not entirely UEFI spec compliant. So instead, use the designated permission attributes to decide how these regions should be mapped. Since UEFIv2.5 introduces a new EFI_MEMORY_RO permission attribute, and redefines EFI_MEMORY_WP as a cacheability attribute, use only the former as a read-only attribute. For setting the PXN bit, the corresponding EFI_MEMORY_XP attribute is used. Signed-off-by: Ard Biesheuvel --- arch/arm64/kernel/efi.c | 32 +++++++++++++------- 1 file changed, 21 insertions(+), 11 deletions(-) diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c index ab21e0d58278..5dcab58d5d30 100644 --- a/arch/arm64/kernel/efi.c +++ b/arch/arm64/kernel/efi.c @@ -247,20 +247,30 @@ static bool __init efi_virtmap_init(void) memrange_efi_to_native(&paddr, &npages); size = npages << PAGE_SHIFT; - pr_info(" EFI remap 0x%016llx => %p\n", - md->phys_addr, (void *)md->virt_addr); - - /* - * Only regions of type EFI_RUNTIME_SERVICES_CODE need to be - * executable, everything else can be mapped with the XN bits - * set. - */ if (!is_normal_ram(md)) prot = __pgprot(PROT_DEVICE_nGnRE); - else if (md->type == EFI_RUNTIME_SERVICES_CODE) - prot = PAGE_KERNEL_EXEC; else - prot = PAGE_KERNEL; + prot = PAGE_KERNEL_EXEC; + + /* + * On 64 KB granule kernels, only use strict permissions when + * the region does not share a 64 KB page frame with another + * region at either end. + */ + if (!IS_ENABLED(CONFIG_ARM64_64K_PAGES) || + !(md->virt_addr % PAGE_SIZE || + (md->phys_addr + md->num_pages * EFI_PAGE_SIZE) % PAGE_SIZE)) { + + if (md->attribute & EFI_MEMORY_RO) + prot |= __pgprot(PTE_RDONLY); + if (md->attribute & EFI_MEMORY_XP) + prot |= __pgprot(PTE_PXN); + } + + pr_info(" EFI remap 0x%016llx => %p (R%c%c)\n", + md->phys_addr, (void *)md->virt_addr, + prot & __pgprot(PTE_RDONLY) ? '-' : 'W', + prot & __pgprot(PTE_PXN) ? '-' : 'X'); create_pgd_mapping(&efi_mm, paddr, md->virt_addr, size, prot); } -- 1.9.1