[Crash-utility] [PATCH v5 09/14] x86_64: Add gdb stack unwinding support

This patch will add stack unwinding support for x86_64 CPU arch. It follows the tech path of ppc64_get_stack_frame() & ppc64_get_cpu_reg() in ppc64.c, to get and consume the cpu regs. One different case is, we need to handle inactive_task_frame structure specifically in x86_64. If inactive_task_frame structure enabled, for inactive tasks, 7 regs can be get from inactive_task_frame in stack, and sp need to rewind back to skip inactive_task_frame structure (See code comments in x86_64.c:x86_64_get_stack_frame()); for active tasks, we get regs by the original way. If inactive_task_frame structure is not enabled, for inactive tasks, the stack frame is organized as linked list, and sp/bp can be get from stack; for active tasks, we get regs by the original way. vmware_vmss_get_cpu_reg() whould be called only for active tasks to get their registers from corresponding CPUs. Otherwise, the standard path of fetching pt_regs from the memory (inactive_task_frame) should be used. Cc: Sourabh Jain <sourabhjain(a)linux.ibm.com&gt; Cc: Hari Bathini <hbathini(a)linux.ibm.com&gt; Cc: Mahesh J Salgaonkar <mahesh(a)linux.ibm.com&gt; Cc: Naveen N. Rao <naveen.n.rao(a)linux.vnet.ibm.com&gt; Cc: Lianbo Jiang <lijiang(a)redhat.com&gt; Cc: HAGIO KAZUHITO(萩尾 一仁) <k-hagio-ab(a)nec.com&gt; Cc: Tao Liu <ltao(a)redhat.com&gt; Cc: Alexey Makhalov <alexey.makhalov(a)broadcom.com&gt; Signed-off-by: Tao Liu <ltao(a)redhat.com&gt; Signed-off-by: Alexey Makhalov <alexey.makhalov(a)broadcom.com&gt; --- defs.h | 19 +++- symbols.c | 14 +++ x86_64.c | 317 +++++++++++++++++++++++++++++++++++++++++++++++++----- 3 files changed, 320 insertions(+), 30 deletions(-) diff --git a/defs.h b/defs.h index 49ace67..d79f5bc 100644 --- a/defs.h +++ b/defs.h @@ -2244,6 +2244,20 @@ struct offset_table { /* stash of commonly-used offsets */ long vmap_node_busy; long rb_list_head; long file_f_inode; + long inactive_task_frame_r15; + long inactive_task_frame_r14; + long inactive_task_frame_r13; + long inactive_task_frame_r12; + long inactive_task_frame_flags; + long inactive_task_frame_si; + long inactive_task_frame_di; + long inactive_task_frame_bx; + long thread_struct_es; + long thread_struct_ds; + long thread_struct_fsbase; + long thread_struct_gsbase; + long thread_struct_fs; + long thread_struct_gs; }; struct size_table { /* stash of commonly-used sizes */ @@ -8019,7 +8033,7 @@ extern int have_full_symbols(void); /* * Register numbers must be in sync with gdb/features/i386/64bit-core.c - * to make crash_target->fetch_registers() ---> machdep->get_cpu_reg() + * to make crash_target->fetch_registers() ---> machdep->get_current_task_reg() * working properly. */ enum x86_64_regnum { @@ -8063,6 +8077,9 @@ enum x86_64_regnum { FOSEG_REGNUM, FOOFF_REGNUM, FOP_REGNUM, + FS_BASE_REGNUM = 152, + GS_BASE_REGNUM, + ORIG_RAX_REGNUM, LAST_REGNUM }; diff --git a/symbols.c b/symbols.c index 69a1fbb..927c5ad 100644 --- a/symbols.c +++ b/symbols.c @@ -11813,6 +11813,20 @@ dump_offset_table(char *spec, ulong makestruct) fprintf(fp, " zs_pool_size_class: %ld\n", OFFSET(zs_pool_size_class)); fprintf(fp, " size_class_size: %ld\n", OFFSET(size_class_size)); fprintf(fp, " zspage_huge: %ld\n", OFFSET(zspage_huge)); + fprintf(fp, " inactive_task_frame_r15: %ld\n", OFFSET(inactive_task_frame_r15)); + fprintf(fp, " inactive_task_frame_r14: %ld\n", OFFSET(inactive_task_frame_r14)); + fprintf(fp, " inactive_task_frame_r13: %ld\n", OFFSET(inactive_task_frame_r13)); + fprintf(fp, " inactive_task_frame_r12: %ld\n", OFFSET(inactive_task_frame_r12)); + fprintf(fp, " inactive_task_frame_flags: %ld\n", OFFSET(inactive_task_frame_flags)); + fprintf(fp, " inactive_task_frame_si: %ld\n", OFFSET(inactive_task_frame_si)); + fprintf(fp, " inactive_task_frame_di: %ld\n", OFFSET(inactive_task_frame_di)); + fprintf(fp, " inactive_task_frame_bx: %ld\n", OFFSET(inactive_task_frame_bx)); + fprintf(fp, " thread_struct_es: %ld\n", OFFSET(thread_struct_es)); + fprintf(fp, " thread_struct_ds: %ld\n", OFFSET(thread_struct_ds)); + fprintf(fp, " thread_struct_fsbase: %ld\n", OFFSET(thread_struct_fsbase)); + fprintf(fp, " thread_struct_gsbase: %ld\n", OFFSET(thread_struct_gsbase)); + fprintf(fp, " thread_struct_fs: %ld\n", OFFSET(thread_struct_fs)); + fprintf(fp, " thread_struct_gs: %ld\n", OFFSET(thread_struct_gs)); fprintf(fp, "\n size_table:\n"); fprintf(fp, " page: %ld\n", SIZE(page)); diff --git a/x86_64.c b/x86_64.c index 24a7040..145436f 100644 --- a/x86_64.c +++ b/x86_64.c @@ -126,7 +126,7 @@ static int x86_64_get_framesize(struct bt_info *, ulong, ulong, char *); static void x86_64_framesize_debug(struct bt_info *); static void x86_64_get_active_set(void); static int x86_64_get_kvaddr_ranges(struct vaddr_range *); -static int x86_64_get_cpu_reg(int, int, const char *, int, void *); +static int x86_64_get_current_task_reg(int, const char *, int, void *); static int x86_64_verify_paddr(uint64_t); static void GART_init(void); static void x86_64_exception_stacks_init(void); @@ -143,6 +143,23 @@ struct machine_specific x86_64_machine_specific = { 0 }; static const char *exception_functions_orig[]; static const char *exception_functions_5_8[]; +/* Use this hardwired version -- sometimes the + * debuginfo doesn't pick this up even though + * it exists in the kernel; it shouldn't change. + */ +struct x86_64_user_regs_struct { + unsigned long r15, r14, r13, r12, bp, bx; + unsigned long r11, r10, r9, r8, ax, cx, dx; + unsigned long si, di, orig_ax, ip, cs; + unsigned long flags, sp, ss, fs_base; + unsigned long gs_base, ds, es, fs, gs; +}; + +struct user_regs_bitmap_struct { + struct x86_64_user_regs_struct ur; + ulong bitmap[32]; +}; + /* * Do all necessary machine-specific setup here. This is called several * times during initialization. @@ -195,7 +212,7 @@ x86_64_init(int when) machdep->machspec->irq_eframe_link = UNINITIALIZED; machdep->machspec->irq_stack_gap = UNINITIALIZED; machdep->get_kvaddr_ranges = x86_64_get_kvaddr_ranges; - machdep->get_current_task_reg = x86_64_get_cpu_reg; + machdep->get_current_task_reg = x86_64_get_current_task_reg; if (machdep->cmdline_args[0]) parse_cmdline_args(); if ((string = pc->read_vmcoreinfo("relocate"))) { @@ -500,6 +517,12 @@ x86_64_init(int when) MEMBER_OFFSET_INIT(thread_struct_rsp, "thread_struct", "sp"); if (INVALID_MEMBER(thread_struct_rsp0)) MEMBER_OFFSET_INIT(thread_struct_rsp0, "thread_struct", "sp0"); + MEMBER_OFFSET_INIT(thread_struct_es, "thread_struct", "es"); + MEMBER_OFFSET_INIT(thread_struct_ds, "thread_struct", "ds"); + MEMBER_OFFSET_INIT(thread_struct_fsbase, "thread_struct", "fsbase"); + MEMBER_OFFSET_INIT(thread_struct_gsbase, "thread_struct", "gsbase"); + MEMBER_OFFSET_INIT(thread_struct_fs, "thread_struct", "fs"); + MEMBER_OFFSET_INIT(thread_struct_gs, "thread_struct", "gs"); STRUCT_SIZE_INIT(tss_struct, "tss_struct"); MEMBER_OFFSET_INIT(tss_struct_ist, "tss_struct", "ist"); if (INVALID_MEMBER(tss_struct_ist)) { @@ -583,17 +606,6 @@ x86_64_init(int when) "user_regs_struct", "r15"); STRUCT_SIZE_INIT(user_regs_struct, "user_regs_struct"); if (!VALID_STRUCT(user_regs_struct)) { - /* Use this hardwired version -- sometimes the - * debuginfo doesn't pick this up even though - * it exists in the kernel; it shouldn't change. - */ - struct x86_64_user_regs_struct { - unsigned long r15, r14, r13, r12, bp, bx; - unsigned long r11, r10, r9, r8, ax, cx, dx; - unsigned long si, di, orig_ax, ip, cs; - unsigned long flags, sp, ss, fs_base; - unsigned long gs_base, ds, es, fs, gs; - }; ASSIGN_SIZE(user_regs_struct) = sizeof(struct x86_64_user_regs_struct); ASSIGN_OFFSET(user_regs_struct_rip) = @@ -891,7 +903,7 @@ x86_64_dump_machdep_table(ulong arg) fprintf(fp, " is_page_ptr: x86_64_is_page_ptr()\n"); fprintf(fp, " verify_paddr: x86_64_verify_paddr()\n"); fprintf(fp, " get_kvaddr_ranges: x86_64_get_kvaddr_ranges()\n"); - fprintf(fp, " get_cpu_reg: x86_64_get_cpu_reg()\n"); + fprintf(fp, "get_current_task_reg: x86_64_get_current_task_reg()\n"); fprintf(fp, " init_kernel_pgd: x86_64_init_kernel_pgd()\n"); fprintf(fp, "clear_machdep_cache: x86_64_clear_machdep_cache()\n"); fprintf(fp, " xendump_p2m_create: %s\n", PVOPS_XEN() ? @@ -4973,22 +4985,143 @@ x86_64_eframe_verify(struct bt_info *bt, long kvaddr, long cs, long ss, return FALSE; } +static ulong +get_reg_from_inactive_task_frame(struct bt_info *bt, char *reg_name, + ulong reg_offset) +{ + ulong reg_value = 0, rsp = 0; + char reg_info[64]; + + snprintf(reg_info, sizeof(reg_info), "inactive_task_frame.%s", reg_name); + + readmem(bt->task + OFFSET(task_struct_thread) + + OFFSET(thread_struct_rsp), KVADDR, &rsp, + sizeof(ulong), "thread_struct.rsp", FAULT_ON_ERROR); + readmem(rsp + reg_offset, KVADDR, &reg_value, + sizeof(ulong), reg_info, FAULT_ON_ERROR); + return reg_value; +} + +#define SET_REG_BITMAP(REGMAP, TYPE, MEMBER) \ + SET_BIT(REGMAP, REG_SEQ(TYPE, MEMBER)) + /* * Get a stack frame combination of pc and ra from the most relevent spot. */ static void x86_64_get_stack_frame(struct bt_info *bt, ulong *pcp, ulong *spp) { - if (bt->flags & BT_DUMPFILE_SEARCH) - return x86_64_get_dumpfile_stack_frame(bt, pcp, spp); + struct user_regs_bitmap_struct *ur_bitmap; + ulong pcp_save = *pcp; + ulong spp_save = *spp; + ulong sp; if (bt->flags & BT_SKIP_IDLE) bt->flags &= ~BT_SKIP_IDLE; + if (pcp) + *pcp = x86_64_get_pc(bt); + if (spp) + sp = *spp = x86_64_get_sp(bt); + ur_bitmap = (struct user_regs_bitmap_struct *)GETBUF(sizeof(*ur_bitmap)); + memset(ur_bitmap, 0, sizeof(*ur_bitmap)); + + if (VALID_MEMBER(inactive_task_frame_bp)) { + if (!is_task_active(bt->task)) { + /* + * For inactive tasks in live and dumpfile, regs can be + * get from inactive_task_frame struct. + */ + ur_bitmap->ur.r15 = get_reg_from_inactive_task_frame(bt, + "r15", OFFSET(inactive_task_frame_r15)); + ur_bitmap->ur.r14 = get_reg_from_inactive_task_frame(bt, + "r14", OFFSET(inactive_task_frame_r14)); + ur_bitmap->ur.r13 = get_reg_from_inactive_task_frame(bt, + "r13", OFFSET(inactive_task_frame_r13)); + ur_bitmap->ur.r12 = get_reg_from_inactive_task_frame(bt, + "r12", OFFSET(inactive_task_frame_r12)); + ur_bitmap->ur.bx = get_reg_from_inactive_task_frame(bt, + "bx", OFFSET(inactive_task_frame_bx)); + ur_bitmap->ur.bp = get_reg_from_inactive_task_frame(bt, + "bp", OFFSET(inactive_task_frame_bp)); + /* + For inactive tasks: + crash> task -x 1|grep sp + sp = 0xffffc90000013d00 + crash> rd ffffc90000013d00 32 + ffffc90000013d00: ffff888104dad4a8 0000000000000000 r15,r14 + ffffc90000013d10: ffff888100280000 ffff888100216500 r13,r12 + ffffc90000013d20: ffff888100217018 ffff88817fd2c800 rbx,rbp + ffffc90000013d30: ffffffff81a6a1b3 ffffc90000013de0 saved_rip,... + ffffc90000013d40: ffff888100000004 99ccbf53ea493000 + ffffc90000013d50: ffff888100216500 ffff888100216500 + + crash> dis __schedule + ... + 0xffffffff81a6a1ab <__schedule+507>: mov %r13,%rsi + 0xffffffff81a6a1ae <__schedule+510>: call 0xffffffff81003490 <__switch_to_asm> + 0xffffffff81a6a1b3 <__schedule+515>: mov %rax,%rdi <<=== saved_rip + ... + crash> dis __switch_to_asm + 0xffffffff81003490 <__switch_to_asm>: push %rbp + 0xffffffff81003491 <__switch_to_asm+1>: push %rbx + 0xffffffff81003492 <__switch_to_asm+2>: push %r12 + 0xffffffff81003494 <__switch_to_asm+4>: push %r13 + 0xffffffff81003496 <__switch_to_asm+6>: push %r14 + 0xffffffff81003498 <__switch_to_asm+8>: push %r15 + 0xffffffff8100349a <__switch_to_asm+10>: mov %rsp,0x14d8(%rdi) + ... + Now saved_rip = ffffffff81a6a1b3, and we are starting + the stack unwind at saved_rip, which is function __schedule() + instead of function __switch_to_asm(), so the stack pointer should + be rewind from ffffc90000013d00 back to ffffc90000013d38, + aka *spp += 7 * reg_len. Otherwise we are unwinding function + __schedule() but with __switch_to_asm()'s stack frame, which + will fail. + */ + sp += 7 * sizeof(unsigned long); + SET_REG_BITMAP(ur_bitmap->bitmap, x86_64_user_regs_struct, r15); + SET_REG_BITMAP(ur_bitmap->bitmap, x86_64_user_regs_struct, r14); + SET_REG_BITMAP(ur_bitmap->bitmap, x86_64_user_regs_struct, r13); + SET_REG_BITMAP(ur_bitmap->bitmap, x86_64_user_regs_struct, r12); + SET_REG_BITMAP(ur_bitmap->bitmap, x86_64_user_regs_struct, bx); + SET_REG_BITMAP(ur_bitmap->bitmap, x86_64_user_regs_struct, bp); + } else { + /* + * For active tasks in dumpfile, we get regs through the + * original way. For active tasks in live, we only get + * ip and sp in the end of the function. + */ + if (bt->flags & BT_DUMPFILE_SEARCH) { + FREEBUF(ur_bitmap); + bt->need_free = FALSE; + *pcp = pcp_save; + *spp = spp_save; + return x86_64_get_dumpfile_stack_frame(bt, pcp, spp); + } + } + } else { + if (!is_task_active(bt->task)) { + readmem(*spp, KVADDR, &(ur_bitmap->ur.bp), + sizeof(ulong), "ur_bitmap->ur.bp", FAULT_ON_ERROR); + SET_REG_BITMAP(ur_bitmap->bitmap, x86_64_user_regs_struct, bp); + } else { + if (bt->flags & BT_DUMPFILE_SEARCH) { + FREEBUF(ur_bitmap); + bt->need_free = FALSE; + *pcp = pcp_save; + *spp = spp_save; + return x86_64_get_dumpfile_stack_frame(bt, pcp, spp); + } + } + } - if (pcp) - *pcp = x86_64_get_pc(bt); - if (spp) - *spp = x86_64_get_sp(bt); + ur_bitmap->ur.ip = *pcp; + ur_bitmap->ur.sp = sp; + SET_REG_BITMAP(ur_bitmap->bitmap, x86_64_user_regs_struct, ip); + SET_REG_BITMAP(ur_bitmap->bitmap, x86_64_user_regs_struct, sp); + + bt->machdep = ur_bitmap; + bt->need_free = TRUE; } /* @@ -6401,6 +6534,17 @@ x86_64_ORC_init(void) }; struct ORC_data *orc; + MEMBER_OFFSET_INIT(inactive_task_frame_bp, "inactive_task_frame", "bp"); + MEMBER_OFFSET_INIT(inactive_task_frame_ret_addr, "inactive_task_frame", "ret_addr"); + MEMBER_OFFSET_INIT(inactive_task_frame_r15, "inactive_task_frame", "r15"); + MEMBER_OFFSET_INIT(inactive_task_frame_r14, "inactive_task_frame", "r14"); + MEMBER_OFFSET_INIT(inactive_task_frame_r13, "inactive_task_frame", "r13"); + MEMBER_OFFSET_INIT(inactive_task_frame_r12, "inactive_task_frame", "r12"); + MEMBER_OFFSET_INIT(inactive_task_frame_flags, "inactive_task_frame", "flags"); + MEMBER_OFFSET_INIT(inactive_task_frame_si, "inactive_task_frame", "si"); + MEMBER_OFFSET_INIT(inactive_task_frame_di, "inactive_task_frame", "di"); + MEMBER_OFFSET_INIT(inactive_task_frame_bx, "inactive_task_frame", "bx"); + if (machdep->flags & FRAMEPOINTER) return; @@ -6458,9 +6602,6 @@ x86_64_ORC_init(void) orc->__stop_orc_unwind = symbol_value("__stop_orc_unwind"); orc->orc_lookup = symbol_value("orc_lookup"); - MEMBER_OFFSET_INIT(inactive_task_frame_bp, "inactive_task_frame", "bp"); - MEMBER_OFFSET_INIT(inactive_task_frame_ret_addr, "inactive_task_frame", "ret_addr"); - orc->has_signal = MEMBER_EXISTS("orc_entry", "signal"); /* added at 6.3 */ orc->has_end = MEMBER_EXISTS("orc_entry", "end"); /* removed at 6.4 */ @@ -9073,17 +9214,135 @@ x86_64_get_kvaddr_ranges(struct vaddr_range *vrp) return cnt; } +#define CHECK_REG_CASE(R, r) \ + case R##_REGNUM: \ + if (!NUM_IN_BITMAP(ur_bitmap->bitmap, \ + REG_SEQ(x86_64_user_regs_struct, r))) { \ + FREEBUF(ur_bitmap); \ + return FALSE; \ + } \ + break; + +#define COPY_REG_CASE(R, r) \ + case R##_REGNUM: \ + if (size != sizeof(ur_bitmap->ur.r)) \ + break; \ + memcpy(value, &ur_bitmap->ur.r, size); \ + ret = TRUE; \ + break; + static int -x86_64_get_cpu_reg(int cpu, int regno, const char *name, +x86_64_get_current_task_reg(int regno, const char *name, int size, void *value) { - if (regno >= LAST_REGNUM) - return FALSE; + struct bt_info bt_info, bt_setup; + struct task_context *tc; + struct user_regs_bitmap_struct *ur_bitmap; + ulong ip, sp; + bool ret = FALSE; + + switch (regno) { + case RAX_REGNUM ... GS_REGNUM: + case FS_BASE_REGNUM ... ORIG_RAX_REGNUM: + break; + default: + return FALSE; + } - if (VMSS_DUMPFILE()) - return vmware_vmss_get_cpu_reg(cpu, regno, name, size, value); + tc = CURRENT_CONTEXT(); + if (!tc) + return FALSE; - return FALSE; + /* + * Task is active, grab CPU's registers + */ + if (is_task_active(tc->task) && VMSS_DUMPFILE()) + return vmware_vmss_get_cpu_reg(tc->processor, regno, name, size, value); + + BZERO(&bt_setup, sizeof(struct bt_info)); + clone_bt_info(&bt_setup, &bt_info, tc); + fill_stackbuf(&bt_info); + + // reusing the get_dumpfile_regs function to get pt regs structure + get_dumpfile_regs(&bt_info, &sp, &ip); + if (bt_info.stackbuf) + FREEBUF(bt_info.stackbuf); + ur_bitmap = (struct user_regs_bitmap_struct *)bt_info.machdep; + if (!ur_bitmap) + return FALSE; + + /* Get all registers from elf notes*/ + if (!bt_info.need_free) { + goto get_all; + } + + /* Get subset registers from stack frame*/ + switch (regno) { + CHECK_REG_CASE(RAX, ax); + CHECK_REG_CASE(RBX, bx); + CHECK_REG_CASE(RCX, cx); + CHECK_REG_CASE(RDX, dx); + CHECK_REG_CASE(RSI, si); + CHECK_REG_CASE(RDI, di); + CHECK_REG_CASE(RBP, bp); + CHECK_REG_CASE(RSP, sp); + CHECK_REG_CASE(R8, r8); + CHECK_REG_CASE(R9, r9); + CHECK_REG_CASE(R10, r10); + CHECK_REG_CASE(R11, r11); + CHECK_REG_CASE(R12, r12); + CHECK_REG_CASE(R13, r13); + CHECK_REG_CASE(R14, r14); + CHECK_REG_CASE(R15, r15); + CHECK_REG_CASE(RIP, ip); + CHECK_REG_CASE(EFLAGS, flags); + CHECK_REG_CASE(CS, cs); + CHECK_REG_CASE(SS, ss); + CHECK_REG_CASE(DS, ds); + CHECK_REG_CASE(ES, es); + CHECK_REG_CASE(FS, fs); + CHECK_REG_CASE(GS, gs); + CHECK_REG_CASE(FS_BASE, fs_base); + CHECK_REG_CASE(GS_BASE, gs_base); + CHECK_REG_CASE(ORIG_RAX, orig_ax); + } + +get_all: + switch (regno) { + COPY_REG_CASE(RAX, ax); + COPY_REG_CASE(RBX, bx); + COPY_REG_CASE(RCX, cx); + COPY_REG_CASE(RDX, dx); + COPY_REG_CASE(RSI, si); + COPY_REG_CASE(RDI, di); + COPY_REG_CASE(RBP, bp); + COPY_REG_CASE(RSP, sp); + COPY_REG_CASE(R8, r8); + COPY_REG_CASE(R9, r9); + COPY_REG_CASE(R10, r10); + COPY_REG_CASE(R11, r11); + COPY_REG_CASE(R12, r12); + COPY_REG_CASE(R13, r13); + COPY_REG_CASE(R14, r14); + COPY_REG_CASE(R15, r15); + COPY_REG_CASE(RIP, ip); + COPY_REG_CASE(EFLAGS, flags); + COPY_REG_CASE(CS, cs); + COPY_REG_CASE(SS, ss); + COPY_REG_CASE(DS, ds); + COPY_REG_CASE(ES, es); + COPY_REG_CASE(FS, fs); + COPY_REG_CASE(GS, gs); + COPY_REG_CASE(FS_BASE, fs_base); + COPY_REG_CASE(GS_BASE, gs_base); + COPY_REG_CASE(ORIG_RAX, orig_ax); + } + + if (bt_info.need_free) { + FREEBUF(ur_bitmap); + bt_info.need_free = FALSE; + } + return ret; } /* -- 2.40.1