[Crash-utility] ARM panic registers

[Per Fransson]

On Tue, Sep 20, 2011 at 8:42 PM, Dave Anderson <anderson at redhat.com> wrote:
>
>
> ----- Original Message -----
>> On Tue, Sep 20, 2011 at 10:41:51AM -0400, Dave Anderson wrote:
>> > >
>> > > static void
>> > > get_netdump_regs_arm(struct bt_info *bt, ulong *eip, ulong *esp)
>> > > {
>> > >   machdep->get_stack_frame(bt, eip, esp);
>> > > }
>> > >
>> > > If we're not going to use the ELF notes, why fail if they're not
>> > > there?
>> >
>> > I'm not sure what you mean about reading "directly from within the
>> > PT_LOAD segments",  but I agree with you that the preliminary "if"
>> > section of get_netdump_regs_arm() which sets bt->machdep is a
>> > no-op -- given that arm_get_dumpfile_stack_frame() just ignores
>> > it, and resets bt->machdep from that ARM-specific ms->crash_task_regs
>> > area.
>> >
>> > Mika, you agree?
>>
>> Absolutely - we already have similar for diskdump:
>>
>> static void
>> get_diskdump_regs_arm(struct bt_info *bt, ulong *eip, ulong *esp)
>> {
>>       machdep->get_stack_frame(bt, eip, esp);
>> }
>>
>> I tested Per's suggestion on my few kdump/netdump vmcores and it
>> works well.
>>
>> If you prefer to have a patch for this change, it is included below
>> (all credits goes to Per).
>>
>> diff --git a/netdump.c b/netdump.c
>> index 1e9960c..a194364 100644
>> --- a/netdump.c
>> +++ b/netdump.c
>> @@ -2580,34 +2580,6 @@ get_netdump_regs_ppc64(struct bt_info *bt,
>> ulong *eip, ulong *esp)
>>  static void
>>  get_netdump_regs_arm(struct bt_info *bt, ulong *eip, ulong *esp)
>>  {
>> -     Elf64_Nhdr *note;
>> -     size_t len;
>> -
>> -     if ((bt->task == tt->panic_task) ||
>> -             (is_task_active(bt->task) && nd->num_prstatus_notes > 1)) {
>> -             /*
>> -              * Registers are saved during the dump process for the
>> -              * panic task. Whereas in kdump, regs are captured for all
>> -              * CPUs if they responded to an IPI.
>> -              */
>> -                if (nd->num_prstatus_notes > 1) {
>> -                     if (!nd->nt_prstatus_percpu[bt->tc->processor])
>> -                             error(FATAL,
>> -                                   "cannot determine NT_PRSTATUS ELF note "
>> -                                   "for %s task: %lx\n",
>> -                                    (bt->task == tt->panic_task) ?
>> -                                    "panic" : "active", bt->task);
>> -                        note = (Elf64_Nhdr *)
>> -
>>                                nd->nt_prstatus_percpu[bt->tc->processor];
>> -             } else
>> -                     note = (Elf64_Nhdr *)nd->nt_prstatus;
>> -
>> -             len = sizeof(Elf64_Nhdr);
>> -             len = roundup(len + note->n_namesz, 4);
>> -             bt->machdep = (void *)((char *)note + len +
>> -                     MEMBER_OFFSET("elf_prstatus", "pr_reg"));
>> -     }
>> -
>>       machdep->get_stack_frame(bt, eip, esp);
>>  }
>
> Queued for crash-5.1.9 -- thanks guys,
>  Dave
>
>
>
>
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Much obliged.

Regards,
Per