[Crash-utility] [Crash Utility] Improvement for getting offline CPU register without symbol "crash_notes"

[HAGIO KAZUHITO(萩尾 一仁)]

Hi James, Nicholas,

sorry for the late reply.

-----Original Message-----
> 
> Dear Maintaniners,
> 
> 
> 
> Sorry for attaching a not readable patch file at previous mail.
> 
> I add the diff of the patch inline for your review.

Thanks.
but please use text format next time, not HTML email, if possible.

> 
> 
> 
> And provide the reason of improvement again and look forward for your feedback.
> 
> 
> 
> We want to improve the crash_tool for the case that need offline cpu register info even Kdump without
> crash_notes.
> 
> 
> 
> For one thing,  we will prepare a Kdump with all CPU register info in ELF note.

Just to clarify, is this not implemented yet?
So currently the subject should be something like "arm64: Get CPU registers
without crash_notes symbol"?

As for the patch itself, I'm fine with it, although it looks like maybe it
can be united with the code when crash_notes exists.

Thanks,
Kazu


> 
> For another thing, we need to modify crash_tool and make it support adding offline cpu register info even
> Kdump without crash_notes.
> 
> 
> 
> 
> 
> Signed-off-by: Nicholas Tang <Nicholas.tang at mediatek.com>
> 
> 
> 
> --- crash-7.3.0/arm64.c  2021-04-27 16:01:07.000000000 +0800
> 
> +++ crash-7.3.0.mod/arm64.c    2021-06-15 17:13:54.037273227 +0800
> 
> @@ -3667,8 +3667,41 @@ arm64_get_crash_notes(void)
> 
>                ulong *notes_ptrs;
> 
>                ulong i, found;
> 
> -              if (!symbol_exists("crash_notes"))
> 
> +             if (!symbol_exists("crash_notes")) {
> 
> +                             if (DISKDUMP_DUMPFILE() || KDUMP_DUMPFILE()) {
> 
> +                                             if (!(ms->panic_task_regs = calloc((size_t)kt->cpus,
> sizeof(struct arm64_pt_regs))))
> 
> +                                                             error(FATAL, "cannot calloc
> panic_task_regs space\n");
> 
> +
> 
> +                                             for  (i = found = 0; i < kt->cpus; i++) {
> 
> +                                                             if (DISKDUMP_DUMPFILE())
> 
> +                                                                             note =
> diskdump_get_prstatus_percpu(i);
> 
> +                                                             else if (KDUMP_DUMPFILE())
> 
> +                                                                             note =
> netdump_get_prstatus_percpu(i);
> 
> +                                                             else {
> 
> +                                                                             error(WARNING, "cpu %d:
> cannot find NT_PRSTATUS note\n", i);
> 
> +                                                                             continue;
> 
> +                                                             }
> 
> +
> 
> +                                                             /*
> 
> +                                                             * Find correct location of note data. This
> contains elf_prstatus
> 
> +                                                             * structure which has registers etc. for
> the crashed task.
> 
> +                                                             */
> 
> +                                                             offset = sizeof(Elf64_Nhdr);
> 
> +                                                             offset = roundup(offset + note->n_namesz,
> 4);
> 
> +                                                             p = (char *)note + offset; /* start of
> elf_prstatus */
> 
> +
> 
> +                                                             BCOPY(p + OFFSET(elf_prstatus_pr_reg),
> &ms->panic_task_regs[i],
> 
> +                                                                   sizeof(struct arm64_pt_regs));
> 
> +
> 
> +                                                             found++;
> 
> +                                             }
> 
> +                             }
> 
> +                             if (!found) {
> 
> +                                             free(ms->panic_task_regs);
> 
> +                                             ms->panic_task_regs = NULL;
> 
> +                             }
> 
>                                return;
> 
> +             }
> 
>                 crash_notes = symbol_value("crash_notes");
> 
> 
> 
> BR
> 
> James Hsu
> 
> From: James Hsu ($B=y7D{b(B)
> Sent: Wednesday, July 7, 2021 3:11 PM
> To: crash-utility at redhat.com
> Cc: Nicholas Tang ($BE"?A51(B); James Hsu ($B=y7D{b(B)
> Subject: [Crash Utility] Improvement for getting offline CPU register without symbol "crash_notes"
> 
> 
> 
> Dear crash_tool maintainers,
> 
> 
> 
> We want to improve the crash_tool for the case that need offline cpu register info even Kdump without
> crash_notes.
> 
> 
> 
> For one thing,  we will prepare a Kdump with all CPU register info in ELF note.
> 
> For another thing, we need to modify crash_tool and make it support adding offline cpu register info even
> Kdump without crash_notes.
> 
> 
> 
> We prepare a patch for the case with ARCH=arm64.
> 
> Please take your time to review our patch and look forward to receving your comments.
> 
> 
> 
> BR
> 
> James Hsu
> 
> 
> 
> 
> 
> 
> 
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