tree 946e2e56ee6d1ea26c4c986448717c7683b8ce0b
parent 609eaf0748a5b9dccf3810a2b822a0559f33c0b2
author Ard Biesheuvel <ard.biesheuvel@linaro.org> 1503085784 +0100
committer Ingo Molnar <mingo@kernel.org> 1503301431 +0200

arm/efi: Split zImage code and data into separate PE/COFF sections

To prevent unintended modifications to the kernel text (malicious or
otherwise) while running the EFI stub, describe the kernel image as
two separate sections: a .text section with read-execute permissions,
covering .text, .rodata, .piggytext and the GOT sections (which the
stub does not care about anyway), and a .data section with read-write
permissions, covering .data and .bss.

This relies on the firmware to actually take the section permission
flags into account, but this is something that is currently being
implemented in EDK2, which means we will likely start seeing it in
the wild between one and two years from now.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20170818194947.19347-12-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>