[Crash-utility] ppc64 specific changes to support kdump vmcore
Dave Anderson
anderson at redhat.com
Tue Feb 14 19:13:40 UTC 2006
Haren Myneni wrote:
> Reposting this patch as it did not made to crash mailing list. Dave,
> Thanks for adding my different e-mail address to subscriber list.
>
No problem -- I prefer to keep this list subscriber-only to avoid the spam
you see on other lists...
>
> Dave,
>
> Attaching a patch which contains ppc64 specific changes to read kdump
> vmcore. As we are saving pt_regs for all cpus, it reads them from vmcore
> instead of looking for specific symbols, used for PPC64 netdump/diskdump
> vmcore. Also, prints regs before any active backtrace. Whereas for
> netdump vmcore, regs will be displayed anyway as part of exception frame
> since the 'bt' command displays from the top frame.
> Verified with "Make Warn"
>
> Please let me know if you have any comments.
>
This patch looks good. No comment... ;-)
>
> As Badari mentioned, when the sparsemem is enabled, pg_dat->node_mem_map
> member does not exists. mem_map for each node is scattered across
> multiple sections and is not contiguous. Therefore, some detailed
> changes are needed. Until we fix this issue, can we include some hack
> so that users can use other commands for vmcore analysis.
> The fix will be:
> if (MEMBER_EXISTS("pglist_data", "node_mem_map"))
> readmem(pgdat+OFFSET(pglist_data_node_mem_map), KVADDR,
> &node_mem_map, sizeof(ulong),
> "node_mem_map", FAULT_ON_ERROR);
>
> [I noticed your response to Badari's posting. Since the sparsemem is
> effected only for powerpc at this point, we thought, user can use the
> limited functionality with the above change. (Ex: bt) until we have the
> complete fix. At least we will be having crash tool available for kdump
> vmore on ppc64. The sparsemem issue will be fixed soon. Ok, please
> ignore this if you prefer to wait for the complete fix]
>
I was tinkering around with this by simulating the bogus setting of
"node_mem_map" above, and I'm surprised that you can get as much
functionality as crash does give you. Most people probably wouldn't even
notice. Anyway, I was about to change my mind, and put the EXISTS
check in for now -- but along with a non-fatal error message that would be
annoying enough for you guys to whip up a real fix. I'll still do that,
unless by "fixed soon", you mean in a day or two?
Dave
>
> Thanks
> Haren
>
> ------------------------------------------------------------------------------------------------------------------------
> diff -Naurp crash-4.0-2.20.orig/netdump.c crash-4.0-2.20/netdump.c
> --- crash-4.0-2.20.orig/netdump.c 2006-02-11 16:50:28.000000000 -0800
> +++ crash-4.0-2.20/netdump.c 2006-02-11 16:50:58.000000000 -0800
> @@ -1680,7 +1680,13 @@ get_netdump_regs_ppc64(struct bt_info *b
> Elf64_Nhdr *note;
> size_t len;
>
> - if (bt->task == tt->panic_task) {
> + 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)
> note = (Elf64_Nhdr *)
> nd->nt_prstatus_percpu[bt->tc->processor];
> diff -Naurp crash-4.0-2.20.orig/ppc64.c crash-4.0-2.20/ppc64.c
> --- crash-4.0-2.20.orig/ppc64.c 2006-02-11 16:50:32.000000000 -0800
> +++ crash-4.0-2.20/ppc64.c 2006-02-13 16:10:56.000000000 -0800
> @@ -1420,20 +1420,11 @@ ppc64_check_eframe(struct ppc64_pt_regs
> return NULL;
> }
>
> -/*
> - * Print exception frame information for ppc64
> - */
> static void
> -ppc64_print_eframe(char *efrm_str, struct ppc64_pt_regs *regs,
> - struct bt_info *bt)
> +ppc64_print_regs(struct ppc64_pt_regs *regs)
> {
> int i;
>
> - if (BT_REFERENCE_CHECK(bt))
> - return;
> -
> - fprintf(fp, " %s [%lx] exception frame:", efrm_str, regs->trap);
> -
> /* print out the gprs... */
> for(i=0; i<32; i++) {
> if(!(i % 3))
> @@ -1465,9 +1456,66 @@ ppc64_print_eframe(char *efrm_str, struc
> fprintf(fp, "DAR: %016lx\n", regs->dar);
> fprintf(fp, " DSISR: %016lx ", regs->dsisr);
> fprintf(fp, " Syscall Result: %016lx\n", regs->result);
> +}
> +
> +/*
> + * Print the exception frame information
> + */
> +static void
> +ppc64_print_eframe(char *efrm_str, struct ppc64_pt_regs *regs,
> + struct bt_info *bt)
> +{
> + if (BT_REFERENCE_CHECK(bt))
> + return;
> +
> + fprintf(fp, " %s [%lx] exception frame:", efrm_str, regs->trap);
> + ppc64_print_regs(regs);
> fprintf(fp, "\n");
> }
>
> +/*
> + * get SP and IP from the saved ptregs.
> + */
> +static int
> +ppc64_kdump_stack_frame(struct bt_info *bt_in, ulong *nip, ulong *ksp)
> +{
> + struct ppc64_pt_regs *pt_regs;
> + unsigned long unip;
> +
> + pt_regs = (struct ppc64_pt_regs *)bt_in->machdep;
> + if (!pt_regs->gpr[1]) {
> + /*
> + * Not collected regs. May be the corresponding CPU not
> + * responded to an IPI.
> + */
> + fprintf(fp, "%0lx: GPR1 register value (SP) was not saved\n",
> + bt_in->task);
> + return FALSE;
> + }
> + *ksp = pt_regs->gpr[1];
> + readmem(*ksp+16, KVADDR, &unip, sizeof(ulong), "Regs NIP value",
> + FAULT_ON_ERROR);
> + *nip = unip;
> +
> + if (bt_in->flags &&
> + ((BT_TEXT_SYMBOLS|BT_TEXT_SYMBOLS_PRINT|BT_TEXT_SYMBOLS_NOPRINT)))
> + return TRUE;
> +
> + /*
> + * Print the collected regs for the active task
> + */
> + ppc64_print_regs(pt_regs);
> +
> + fprintf(fp, " NIP [%016lx] %s\n", pt_regs->nip,
> + closest_symbol(pt_regs->nip));
> + if (unip != pt_regs->link)
> + fprintf(fp, " LR [%016lx] %s\n", pt_regs->link,
> + closest_symbol(pt_regs->link));
> +
> + fprintf(fp, "\n");
> +
> + return TRUE;
> +}
>
> /*
> * Get the starting point for the active cpus in a diskdump/netdump.
> @@ -1485,12 +1533,18 @@ ppc64_get_dumpfile_stack_frame(struct bt
> ulong ur_ksp = 0;
> int check_hardirq, check_softirq;
> int check_intrstack = TRUE;
> + struct ppc64_pt_regs *pt_regs;
> +
> + /*
> + * For the kdump vmcore, Use SP and IP values that are saved in ptregs.
> + */
> + if (pc->flags && KDUMP)
> + return ppc64_kdump_stack_frame(bt_in, nip, ksp);
>
> bt = &bt_local;
> BCOPY(bt_in, bt, sizeof(struct bt_info));
> ms = machdep->machspec;
> ur_nip = ur_ksp = 0;
> - struct ppc64_pt_regs *pt_regs;
>
> panic_task = tt->panic_task == bt->task ? TRUE : FALSE;
>
>
> ------------------------------------------------------------------------------------------------------------------------
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