Re: [PATCH v2 6/9] s390/module: Use s390_kernel_write() for late relocations

Joe Lawrence <joe.lawrence@xxxxxxxxxx> · Thu, 30 Apr 2020 13:04:10 -0400

On 4/30/20 12:48 PM, Josh Poimboeuf wrote:
On Thu, Apr 30, 2020 at 10:38:21AM -0400, Joe Lawrence wrote:
On Thu, Apr 23, 2020 at 01:10:30PM -0500, Josh Poimboeuf wrote:
This is more of note for the future, but when/if we add livepatch
support on arm64 we'll need to make the very same adjustment there as
well.  See the following pattern:

arch/arm64/kernel/module.c:

   reloc_insn_movw()
   reloc_insn_imm()
   reloc_insn_adrp()

     *place = cpu_to_le32(insn);

maybe something like aarch64_insn_patch_text_nosync() could be used
there, I dunno. (It looks like ftrace and jump_labels are using that
interface.)

This is outside the scope of the patchset, but I thought I'd mention it
as I was curious to see how other arches were currently handling their
relocation updates.

True... I suspect your klp-convert selftests will catch that?

Indeed.  Actually I had hacked enough livepatch code support on ARM to 
see what happened when converting and loading the test patches :)

-- Joe