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The new Properties Table feature introduced in UEFIv2.5 may split memory regions that cover PE/COFF memory images into separate code and data regions. Since these regions only differ in the type (runtime code vs runtime data) and the permission bits, but not in the memory type attributes (UC/WC/WT/WB), the spec does not require them to be aligned to 64 KB. Since the relative offset of PE/COFF .text and .data segments cannot be changed on the fly, this means that we can no longer pad out those regions to be mappable using 64 KB pages. Unfortunately, there is no annotation in the UEFI memory map that identifies data regions that were split off from a code region, so we must apply this logic to all adjacent runtime regions whose attributes only differ in the permission bits. So instead of rounding each memory region to 64 KB alignment at both ends, only round down regions that are not directly preceded by another runtime region with the same type attributes. Since the UEFI spec does not mandate that the memory map be sorted, this means we also need to sort it first. Note that this change will result in all EFI_MEMORY_RUNTIME regions whose start addresses are not aligned to the OS page size to be mapped with executable permissions (i.e., on kernels compiled with 64 KB pages). However, since these mappings are only active during the time that UEFI Runtime Services are being invoked, the window for abuse is rather small. Tested-by: Mark Salter <msalter@redhat.com> Tested-by: Mark Rutland <mark.rutland@arm.com> [UEFI 2.4 only] Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Matt Fleming <matt.fleming@intel.com> Reviewed-by: Mark Salter <msalter@redhat.com> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Cc: <stable@vger.kernel.org> # v4.0+ Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Leif Lindholm <leif.lindholm@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/1443218539-7610-3-git-send-email-matt@codeblueprint.co.uk Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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| .. | ||
| arm-stub.c | ||
| efi-stub-helper.c | ||
| efistub.h | ||
| fdt.c | ||
| Makefile | ||