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

Joe Lawrence
2020-04-30T17:04:22Z

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