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

[yunhui cui]

Hi  Björn,

On Thu, Aug 17, 2023 at 6:03 PM Björn Töpel <bjorn at kernel.org> wrote:
>
> yunhui cui <cuiyunhui at bytedance.com> writes:
>
> > Hi Björn,
> >
> > On Wed, Aug 16, 2023 at 11:11 PM Björn Töpel <bjorn at 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?
Yeah, It works for me, I'll update the patch to v3 and send it.

Thanks,
Yunhui