[Crash-utility] [PATCH] ppc64: rework bt command
Dave Anderson
anderson at redhat.com
Fri Sep 7 20:10:14 UTC 2018
----- Original Message -----
> Commit 3db3d3992d78 was aimed at making 'bt' work for dumpfiles saved
> with fadump but it introduced a bit of unwarranted complexity in 'bt'
> command processing. Rework 'bt' command processing for PPC64 arch to
> make it a little less compilated and also, print symbols for NIP and
> LR registers on exception frames.
>
> Signed-off-by: Hari Bathini <hbathini at linux.ibm.com>
Thanks, Hari. As we discussed in the related bugzilla, this looks good.
Queued for crash-7.2.4:
https://github.com/crash-utility/crash/commit/5fe78861ea1589084f6a2956a6ff63677c9269e1
Dave
> ---
> ppc64.c | 140
> +++++++++++++++++++++++++++++++++++++++++++++------------------
> 1 file changed, 99 insertions(+), 41 deletions(-)
>
> diff --git a/ppc64.c b/ppc64.c
> index f5d0dac..03fecd3 100644
> --- a/ppc64.c
> +++ b/ppc64.c
> @@ -2093,15 +2093,10 @@ ppc64_print_stack_entry(int frame,
> lr);
> return;
> }
> - if (req->pc != lr) {
> - fprintf(fp, "\n%s[Link Register] ",
> - frame < 10 ? " " : "");
> - fprintf(fp, "[%lx] %s at %lx",
> - req->sp, lrname, lr);
> - }
> req->ra = lr;
> }
> - if (!req->name || STREQ(req->name,lrname))
> + if (!req->name || STREQ(req->name, lrname) ||
> + !is_kernel_text(req->pc))
> fprintf(fp, " (unreliable)");
>
> fprintf(fp, "\n");
> @@ -2219,6 +2214,22 @@ ppc64_print_regs(struct ppc64_pt_regs *regs)
> fprintf(fp, " Syscall Result: %016lx\n", regs->result);
> }
>
> +static void ppc64_print_nip_lr(struct ppc64_pt_regs *regs, int print_lr)
> +{
> + char buf[BUFSIZE];
> + char *sym_buf;
> +
> + sym_buf = value_to_symstr(regs->nip, buf, 0);
> + if (sym_buf[0] != NULLCHAR)
> + fprintf(fp, " [NIP : %s]\n", sym_buf);
> +
> + if (print_lr) {
> + sym_buf = value_to_symstr(regs->link, buf, 0);
> + if (sym_buf[0] != NULLCHAR)
> + fprintf(fp, " [LR : %s]\n", sym_buf);
> + }
> +}
> +
> /*
> * Print the exception frame information
> */
> @@ -2231,6 +2242,59 @@ ppc64_print_eframe(char *efrm_str, struct
> ppc64_pt_regs *regs,
>
> fprintf(fp, " %s [%lx] exception frame:\n", efrm_str, regs->trap);
> ppc64_print_regs(regs);
> + ppc64_print_nip_lr(regs, 1);
> +}
> +
> +/*
> + * For vmcore typically saved with KDump or FADump, get SP and IP values
> + * from the saved ptregs.
> + */
> +static int
> +ppc64_vmcore_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 || !pt_regs->gpr[1]) {
> + /*
> + * Not collected regs. May be the corresponding CPU not
> + * responded to an IPI in case of KDump OR f/w has not
> + * not provided the register info in case of FADump.
> + */
> + fprintf(fp, "%0lx: GPR1 register value (SP) was not saved\n",
> + bt_in->task);
> + return FALSE;
> + }
> + *ksp = pt_regs->gpr[1];
> + if (IS_KVADDR(*ksp)) {
> + readmem(*ksp+16, KVADDR, &unip, sizeof(ulong), "Regs NIP value",
> + FAULT_ON_ERROR);
> + *nip = unip;
> + } else {
> + if (IN_TASK_VMA(bt_in->task, *ksp))
> + fprintf(fp, "%0lx: Task is running in user space\n",
> + bt_in->task);
> + else
> + fprintf(fp, "%0lx: Invalid Stack Pointer %0lx\n",
> + bt_in->task, *ksp);
> + *nip = pt_regs->nip;
> + }
> +
> + 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);
> + if (!IS_KVADDR(*ksp))
> + return FALSE;
> +
> + ppc64_print_nip_lr(pt_regs, (unip != pt_regs->link) ? 1 : 0);
> +
> + return TRUE;
> }
>
> /*
> @@ -2239,7 +2303,7 @@ ppc64_print_eframe(char *efrm_str, struct ppc64_pt_regs
> *regs,
> static int
> ppc64_get_dumpfile_stack_frame(struct bt_info *bt_in, ulong *nip, ulong
> *ksp)
> {
> - int i;
> + int i, ret, panic_task;
> char *sym;
> ulong *up;
> struct bt_info bt_local, *bt;
> @@ -2251,11 +2315,29 @@ ppc64_get_dumpfile_stack_frame(struct bt_info *bt_in,
> ulong *nip, ulong *ksp)
> struct ppc64_pt_regs *pt_regs;
> struct syment *sp;
>
> - bt = &bt_local;
> - BCOPY(bt_in, bt, sizeof(struct bt_info));
> - ms = machdep->machspec;
> + bt = &bt_local;
> + BCOPY(bt_in, bt, sizeof(struct bt_info));
> + ms = machdep->machspec;
> + ur_nip = ur_ksp = 0;
> +
> + panic_task = tt->panic_task == bt->task ? TRUE : FALSE;
>
> check_hardirq = check_softirq = tt->flags & IRQSTACKS ? TRUE : FALSE;
> + if (panic_task && bt->machdep) {
> + pt_regs = (struct ppc64_pt_regs *)bt->machdep;
> + ur_nip = pt_regs->nip;
> + ur_ksp = pt_regs->gpr[1];
> + } else if ((pc->flags & KDUMP) ||
> + ((pc->flags & DISKDUMP) &&
> + (*diskdump_flags & KDUMP_CMPRS_LOCAL))) {
> + /*
> + * For the KDump or FADump vmcore, use SP and IP values
> + * that are saved in ptregs.
> + */
> + ret = ppc64_vmcore_stack_frame(bt_in, nip, ksp);
> + if (ret)
> + return TRUE;
> + }
>
> if (bt->task != tt->panic_task) {
> char cpu_frozen = FALSE;
> @@ -2385,38 +2467,14 @@ retry:
> check_intrstack = FALSE;
> goto retry;
> }
> -
> /*
> - * We didn't find what we were looking for, so try to use
> - * the SP and IP values saved in ptregs.
> + * We didn't find what we were looking for, so just use what was
> + * passed in the ELF header.
> */
> - pt_regs = (struct ppc64_pt_regs *)bt_in->machdep;
> - if (!pt_regs || !pt_regs->gpr[1]) {
> - /*
> - * Not collected regs. May be the corresponding CPU did not
> - * respond to an IPI.
> - */
> - if (CRASHDEBUG(1))
> - fprintf(fp, "%0lx: GPR1(SP) register value not saved\n",
> - bt_in->task);
> - } else {
> - *ksp = pt_regs->gpr[1];
> - if (IS_KVADDR(*ksp)) {
> - readmem(*ksp+16, KVADDR, nip, sizeof(ulong),
> - "Regs NIP value", FAULT_ON_ERROR);
> - ppc64_print_regs(pt_regs);
> - return TRUE;
> - } else {
> - if (IN_TASK_VMA(bt_in->task, *ksp))
> - fprintf(fp, "%0lx: Task is running in user space\n",
> - bt_in->task);
> - else
> - fprintf(fp, "%0lx: Invalid Stack Pointer %0lx\n",
> - bt_in->task, *ksp);
> - *nip = pt_regs->nip;
> - ppc64_print_regs(pt_regs);
> - return FALSE;
> - }
> + if (ur_nip && ur_ksp) {
> + *nip = ur_nip;
> + *ksp = ur_ksp;
> + return TRUE;
> }
>
> console("ppc64_get_dumpfile_stack_frame: cannot find SP for panic
> task\n");
>
>
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