arm64/efi: Apply strict permissions to UEFI Runtime Services regions
commit1fd55a9a09b0293af95ab4299b108f030fef4464
authorArd Biesheuvel <ard.biesheuvel@linaro.org>
Mon, 25 Apr 2016 20:06:43 +0000 (25 21:06 +0100)
committerIngo Molnar <mingo@kernel.org>
Thu, 28 Apr 2016 09:33:53 +0000 (28 11:33 +0200)
tree38a49c1e7a44b7bd8e62b215f9fbe9266f310c69
parent9fc68b717c24a215a32c1b4e05b30433cafb2599
arm64/efi: Apply strict permissions to UEFI Runtime Services regions

Recent UEFI versions expose permission attributes for runtime services
memory regions, either in the UEFI memory map or in the separate memory
attributes table. This allows the kernel to map these regions with
stricter permissions, rather than the RWX permissions that are used by
default. So wire this up in our mapping routine.

Note that in the absence of permission attributes, we still only map
regions of type EFI_RUNTIME_SERVICE_CODE with the executable bit set.
Also, we base the mapping attributes of EFI_MEMORY_MAPPED_IO on the
type directly rather than on the absence of the EFI_MEMORY_WB attribute.
This is more correct, but is also required for compatibility with the
upcoming support for the Memory Attributes Table, which only carries
permission attributes, not memory type attributes.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Jones <pjones@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1461614832-17633-12-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
arch/arm64/kernel/efi.c