[Crash-utility] arm64: Get CPU registers without crash_notes symbol

[James Hsu]

Dear Kazu,

Sorry for late reply
Thanks for your suggestion and I have prepared a V2 patch, please help
to review.

BTW, I have switched to evolution mail system, if still look like html
format, please let me know, thanks.

Signed-off-by: James Hsu <james.hsu at mediatek.com> 

diff --git a/arm64.c b/arm64.c
index 8934961..03c8167 100644
--- a/arm64.c
+++ b/arm64.c
@@ -3667,8 +3667,42 @@ 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);
+
+				if(!note) {
+					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");
 
Thanks
James Hsu

On Wed, 2021-08-11 at 02:52 +0000, HAGIO KAZUHITO(萩尾　一仁) wrote:
> -----Original Message-----
> > 
> > Dear Crash 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.
> > It is verified with our kdump without crash_note and can get all
> > cpu register.
> > Please take your time to review our patch and look forward to
> > receiving your comments.
> > 
> > Patch detail as below
> 
> I've rewritten the commit log, is this ok?
> --
> arm64: Get CPU registers from ELF notes even without crash_notes
> symbol
> 
> Currently arm64 crash retrieves the CPU registers from crash_notes
> symbol
> or ELF notes only when the symbol exists, but there are dumpfiles
> which
> have the registers in ELF notes without the symbol.
> 
> With the patch, crash can retrieve the registers from ELF notes
> without
> the crash_notes symbol.
> --
> 
> And please add Signed-off-by tag.
> 
> > --- 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;
> > +				}
> 
> This else block should be separated from the if block like this?
> 
> if (!note) {
> 	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;
> > +		}
> 
> This if block should be within the if (DISKDUMP_DUMPFILE()... block.
> 
> >  		return;
> > +	}
> >  
> >  	crash_notes = symbol_value("crash_notes");
> >  
> 
> (and this email still looks HTML one to me :-)
> 
> Thanks,
> Kazu
> 
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