Messages in this thread | | | Date | Fri, 8 Apr 2022 13:41:33 +0200 | From | Peter Zijlstra <> | Subject | Re: [RFC PATCH v1 0/9] arm64: livepatch: Use DWARF Call Frame Information for frame pointer validation |
| |
Right; so not having seen the patches due to Madhaven's email being broken, I can perhaps less appreciated the crazy involved.
On Thu, Apr 07, 2022 at 05:21:51PM -0700, Josh Poimboeuf wrote: > 2) > > If I understand correctly, objtool is converting parts of DWARF to a new > format which can then be read by the kernel. In that case, please don't > call it DWARF as that will cause a lot of confusion. > > There are actually several similarities between your new format and ORC, > which is also an objtool-created DWARF alternative. It would be > interesting to see if they could be combined somehow.
What Josh said; please use/extend ORC.
I really don't understand where all this crazy is coming from; why does objtool need to do something radically weird for ARM64?
There are existing ARM64 patches for objtool; in fact they have recently been re-posted:
https://lkml.kernel.org/r/20220407120141.43801-1-chenzhongjin@huawei.com
The only tricky bit seems to be the whole jump-table issue. Using DWARF as input to deal with jump-tables should be possible -- exceedingly overkill, but possible I suppose. Mandating DWARF sucks though, compile times are so much worse with DWARVES on :/
Once objtool can properly follow/validate ARM64 code, it should be fairly straight forward to have it generate ORC data just like it does on x86_64.
| |