On 4 September 2017 at 18:17, Nicolas Pitre [off-list ref] wrote:

On Sun, 3 Sep 2017, Ard Biesheuvel wrote:

quoted

To avoid having to relocate the contents of extable entries at
runtime when running with KASLR enabled, wire up the existing
support for emitting them as relative references. This ensures
these quantities are invariant under runtime relocation.

Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Ard Biesheuvel <redacted>

Could it be better to have a macro that encapsulates exception entries
e.g.:

        .macro ex_entry insn fixup
        .long   \insn - ., \fixup - .
        .endif

so that if ever this changes again or for whatever reason someone needs
absolute entries then this won't have to be done everywhere. The section
switch could be included in such a macro too. And it is so easy to
forget to do the "- ." when adding new entries.

Good point. I will change that.