[Crash-utility] [PATCH v4 5/5] ppc64: Add gdb multi-stack unwind support

Please note, there is a known issue which some ppc cannot stack unwind successfully as: crash> bt PID: 2 TASK: c000000004797f80 CPU: 0 COMMAND: "kthreadd" #0 [c00000000484fbc0] _end at c00000000484fd70 (unreliable) #1 [c00000000484fd70] __switch_to at c00000000001fabc #2 [c00000000484fdd0] __schedule at c0000000011ca9dc #3 [c00000000484feb0] schedule at c0000000011caeb0 #4 [c00000000484ff20] kthreadd at c0000000001af6c4 #5 [c00000000484ffe0] start_kernel_thread at c00000000000ded8 crash> gdb bt #0 0xc00000000484fd70 in ?? () gdb: gdb request failed: bt This has nothing to do with bt/gdb bt, see root cause in [1][2]. [1]: https://www.mail-archive.com/devel@lists.crash-utility.osci.io/msg01124.html [2]: https://www.mail-archive.com/devel@lists.crash-utility.osci.io/msg01139.html Co-developed-by: Alexey Makhalov <alexey.makhalov(a)broadcom.com&gt; Co-developed-by: Tao Liu <ltao(a)redhat.com&gt; Signed-off-by: Tao Liu <ltao(a)redhat.com&gt; --- ppc64.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 64 insertions(+), 6 deletions(-) diff --git a/ppc64.c b/ppc64.c index 532eb3f..d1a5067 100644 --- a/ppc64.c +++ b/ppc64.c @@ -2053,6 +2053,7 @@ ppc64_back_trace_cmd(struct bt_info *bt) char buf[BUFSIZE]; struct gnu_request *req; extern void print_stack_text_syms(struct bt_info *, ulong, ulong); + extra_stacks_idx = 0; bt->flags |= BT_EXCEPTION_FRAME; @@ -2071,6 +2072,29 @@ ppc64_back_trace_cmd(struct bt_info *bt) req->pc = bt->instptr; req->sp = bt->stkptr; + if (is_task_active(bt->task)) { + if (!extra_stacks_regs[extra_stacks_idx]) { + extra_stacks_regs[extra_stacks_idx] = + (struct user_regs_bitmap_struct *) + malloc(sizeof(struct user_regs_bitmap_struct)); + } + memset(extra_stacks_regs[extra_stacks_idx], 0, + sizeof(struct user_regs_bitmap_struct)); + extra_stacks_regs[extra_stacks_idx]->ur.nip = req->pc; + extra_stacks_regs[extra_stacks_idx]->ur.gpr[1] = req->sp; + SET_BIT(extra_stacks_regs[extra_stacks_idx]->bitmap, + REG_SEQ(ppc64_pt_regs, nip)); + SET_BIT(extra_stacks_regs[extra_stacks_idx]->bitmap, + REG_SEQ(ppc64_pt_regs, gpr[0]) + 1); + if (!bt->machdep || + (extra_stacks_regs[extra_stacks_idx]->ur.gpr[1] != + ((struct user_regs_bitmap_struct *)(bt->machdep))->ur.gpr[1] && + extra_stacks_regs[extra_stacks_idx]->ur.nip != + ((struct user_regs_bitmap_struct *)(bt->machdep))->ur.nip)) { + gdb_add_substack (extra_stacks_idx++); + } + } + if (bt->flags & (BT_TEXT_SYMBOLS|BT_TEXT_SYMBOLS_PRINT|BT_TEXT_SYMBOLS_NOPRINT)) { if (!INSTACK(req->sp, bt)) @@ -2512,6 +2536,28 @@ 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); + + if (!((regs->msr >> MSR_PR_LG) & 0x1) && + !(bt->flags & BT_EFRAME_SEARCH)) { + if (!extra_stacks_regs[extra_stacks_idx]) { + extra_stacks_regs[extra_stacks_idx] = + (struct user_regs_bitmap_struct *) + malloc(sizeof(struct user_regs_bitmap_struct)); + } + memset(extra_stacks_regs[extra_stacks_idx], 0, + sizeof(struct user_regs_bitmap_struct)); + memcpy(&extra_stacks_regs[extra_stacks_idx]->ur, regs, + sizeof(struct ppc64_pt_regs)); + for (int i = 0; i < sizeof(struct ppc64_pt_regs)/sizeof(ulong); i++) + SET_BIT(extra_stacks_regs[extra_stacks_idx]->bitmap, i); + if (!bt->machdep || + (extra_stacks_regs[extra_stacks_idx]->ur.gpr[1] != + ((struct user_regs_bitmap_struct *)(bt->machdep))->ur.gpr[1] && + extra_stacks_regs[extra_stacks_idx]->ur.nip != + ((struct user_regs_bitmap_struct *)(bt->machdep))->ur.nip)) { + gdb_add_substack (extra_stacks_idx++); + } + } } static int @@ -2552,6 +2598,12 @@ ppc64_get_current_task_reg(int regno, const char *name, int size, tc = CURRENT_CONTEXT(); if (!tc) return FALSE; + + if (sid && sid <= extra_stacks_idx) { + ur_bitmap = extra_stacks_regs[sid - 1]; + goto get_sub; + } + BZERO(&bt_setup, sizeof(struct bt_info)); clone_bt_info(&bt_setup, &bt_info, tc); fill_stackbuf(&bt_info); @@ -2570,39 +2622,45 @@ ppc64_get_current_task_reg(int regno, const char *name, int size, goto get_all; } +get_sub: switch (regno) { case PPC64_R0_REGNUM ... PPC64_R31_REGNUM: if (!NUM_IN_BITMAP(ur_bitmap->bitmap, REG_SEQ(ppc64_pt_regs, gpr[0]) + regno - PPC64_R0_REGNUM)) { - FREEBUF(ur_bitmap); + if (!sid) + FREEBUF(ur_bitmap); return FALSE; } break; case PPC64_PC_REGNUM: if (!NUM_IN_BITMAP(ur_bitmap->bitmap, REG_SEQ(ppc64_pt_regs, nip))) { - FREEBUF(ur_bitmap); + if (!sid) + FREEBUF(ur_bitmap); return FALSE; } break; case PPC64_MSR_REGNUM: if (!NUM_IN_BITMAP(ur_bitmap->bitmap, REG_SEQ(ppc64_pt_regs, msr))) { - FREEBUF(ur_bitmap); + if (!sid) + FREEBUF(ur_bitmap); return FALSE; } break; case PPC64_LR_REGNUM: if (!NUM_IN_BITMAP(ur_bitmap->bitmap, REG_SEQ(ppc64_pt_regs, link))) { - FREEBUF(ur_bitmap); + if (!sid) + FREEBUF(ur_bitmap); return FALSE; } break; case PPC64_CTR_REGNUM: if (!NUM_IN_BITMAP(ur_bitmap->bitmap, REG_SEQ(ppc64_pt_regs, ctr))) { - FREEBUF(ur_bitmap); + if (!sid) + FREEBUF(ur_bitmap); return FALSE; } break; @@ -2645,7 +2703,7 @@ get_all: ret = TRUE; break; } - if (bt_info.need_free) { + if (!sid && bt_info.need_free) { FREEBUF(ur_bitmap); bt_info.need_free = FALSE; } -- 2.47.0