On 01/04/2016 06:46 AM, Will Deacon wrote:

On Sun, Jan 03, 2016 at 05:05:57PM +0100, Ard Biesheuvel wrote:

quoted

Instead of using absolute addresses for both the exception location
and the fixup, use offsets relative to the exception table entry values.
Not only does this cut the size of the exception table in half, it is
also a prerequisite for KASLR, since absolute exception table entries
are subject to dynamic relocation, which is incompatible with the sorting
of the exception table that occurs at build time.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <redacted>
Signed-off-by: Ard Biesheuvel <redacted>
---

Note that this patch supersedes the version I sent as part of the series that
implements KASLR for arm64: http://thread.gmane.org/gmane.linux.kernel/2116531

 arch/arm64/include/asm/assembler.h   |  2 +-
 arch/arm64/include/asm/futex.h       |  4 ++--
 arch/arm64/include/asm/uaccess.h     | 18 ++++++++++--------
 arch/arm64/kernel/armv8_deprecated.c |  4 ++--
 arch/arm64/mm/extable.c              |  2 +-
 scripts/sortextable.c                |  2 +-
 6 files changed, 17 insertions(+), 15 deletions(-)

This looks good to me, so for the arm64 part (i.e. this patch):

  Acked-by: Will Deacon [off-list ref]

May I humbly ask why the [Finnish] you don't use the equivalent of the
x86 _ASM_EXTABLE() macro?  In fact, why don't we make that one generic, too?

	-hpa