Re: [External] Re: [PATCH v2] riscv: Dump user opcode bytes on fatal faults

["Björn Töpel" <bjorn@kernel.org>]

yunhui cui <cuiyunhui@bytedance.com> writes:

> Hi Björn,
>
> On Wed, Aug 16, 2023 at 11:11 PM Björn Töpel <bjorn@kernel.org> wrote:
>>
>> Hi Yunhui,
>>
>> Waking up the dead! ;-)
>>
>
>>
>> X86's show_opcodes() is used both for kernel oops:es, and userland
>> unhandled signals. On RISC-V there's dump_kernel_instr() added in commit
>> eb165bfa8eaf ("riscv: Add instruction dump to RISC-V splats").
>>
>> Wdyt about reworking that function, so that it works for userland epc as
>> well? I think it's useful to have the surrounding instruction context,
>> and not just on instruction.
>
> Okay,  Based on your suggestion, I'm going to rename dump_kernel_instr
> to dump_instr. Like:
> static void dump_instr(const char *loglvl, struct pt_regs *regs)
> {
> ...
>                 if (user_mode(regs))
>                         bad = get_user_nofault(val, &insns[i]);
>                 else
>                         bad = get_kernel_nofault(val, &insns[i]);
> ...
> }
>
> What do you think?

Yeah, looks good! Does that work for you?


Björn