[Crash-utility] ARM panic registers

[Dave Anderson]

----- 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