-/*
- * Post mortem Dwarf CFI based unwinding on top of regs and stack dumps.
- *
- * Lots of this code have been borrowed or heavily inspired from parts of
- * the libunwind 0.99 code which are (amongst other contributors I may have
- * forgotten):
- *
- * Copyright (C) 2002-2007 Hewlett-Packard Co
- * Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
- *
- * And the bugs have been added by:
- *
- * Copyright (C) 2010, Frederic Weisbecker <fweisbec@gmail.com>
- * Copyright (C) 2012, Jiri Olsa <jolsa@redhat.com>
- *
- */
-
-#include <elf.h>
-#include <gelf.h>
-#include <fcntl.h>
-#include <string.h>
-#include <unistd.h>
-#include <sys/mman.h>
-#include <linux/list.h>
-#include <libunwind.h>
-#include <libunwind-ptrace.h>
-#include "callchain.h"
+#include "unwind.h"
#include "thread.h"
#include "session.h"
-#include "perf_regs.h"
-#include "unwind.h"
-#include "symbol.h"
-#include "util.h"
#include "debug.h"
-#include "asm/bug.h"
-
-extern int
-UNW_OBJ(dwarf_search_unwind_table) (unw_addr_space_t as,
- unw_word_t ip,
- unw_dyn_info_t *di,
- unw_proc_info_t *pi,
- int need_unwind_info, void *arg);
-
-#define dwarf_search_unwind_table UNW_OBJ(dwarf_search_unwind_table)
-
-extern int
-UNW_OBJ(dwarf_find_debug_frame) (int found, unw_dyn_info_t *di_debug,
- unw_word_t ip,
- unw_word_t segbase,
- const char *obj_name, unw_word_t start,
- unw_word_t end);
-
-#define dwarf_find_debug_frame UNW_OBJ(dwarf_find_debug_frame)
-
-#define DW_EH_PE_FORMAT_MASK 0x0f /* format of the encoded value */
-#define DW_EH_PE_APPL_MASK 0x70 /* how the value is to be applied */
-
-/* Pointer-encoding formats: */
-#define DW_EH_PE_omit 0xff
-#define DW_EH_PE_ptr 0x00 /* pointer-sized unsigned value */
-#define DW_EH_PE_udata4 0x03 /* unsigned 32-bit value */
-#define DW_EH_PE_udata8 0x04 /* unsigned 64-bit value */
-#define DW_EH_PE_sdata4 0x0b /* signed 32-bit value */
-#define DW_EH_PE_sdata8 0x0c /* signed 64-bit value */
-
-/* Pointer-encoding application: */
-#define DW_EH_PE_absptr 0x00 /* absolute value */
-#define DW_EH_PE_pcrel 0x10 /* rel. to addr. of encoded value */
-
-/*
- * The following are not documented by LSB v1.3, yet they are used by
- * GCC, presumably they aren't documented by LSB since they aren't
- * used on Linux:
- */
-#define DW_EH_PE_funcrel 0x40 /* start-of-procedure-relative */
-#define DW_EH_PE_aligned 0x50 /* aligned pointer */
+#include "arch/common.h"
-/* Flags intentionaly not handled, since they're not needed:
- * #define DW_EH_PE_indirect 0x80
- * #define DW_EH_PE_uleb128 0x01
- * #define DW_EH_PE_udata2 0x02
- * #define DW_EH_PE_sleb128 0x09
- * #define DW_EH_PE_sdata2 0x0a
- * #define DW_EH_PE_textrel 0x20
- * #define DW_EH_PE_datarel 0x30
- */
+struct unwind_libunwind_ops __weak *local_unwind_libunwind_ops;
+struct unwind_libunwind_ops __weak *x86_32_unwind_libunwind_ops;
+struct unwind_libunwind_ops __weak *arm64_unwind_libunwind_ops;
-struct unwind_info {
- struct perf_sample *sample;
- struct machine *machine;
- struct thread *thread;
-};
-
-#define dw_read(ptr, type, end) ({ \
- type *__p = (type *) ptr; \
- type __v; \
- if ((__p + 1) > (type *) end) \
- return -EINVAL; \
- __v = *__p++; \
- ptr = (typeof(ptr)) __p; \
- __v; \
- })
-
-static int __dw_read_encoded_value(u8 **p, u8 *end, u64 *val,
- u8 encoding)
+static void unwind__register_ops(struct thread *thread,
+ struct unwind_libunwind_ops *ops)
{
- u8 *cur = *p;
- *val = 0;
-
- switch (encoding) {
- case DW_EH_PE_omit:
- *val = 0;
- goto out;
- case DW_EH_PE_ptr:
- *val = dw_read(cur, unsigned long, end);
- goto out;
- default:
- break;
- }
-
- switch (encoding & DW_EH_PE_APPL_MASK) {
- case DW_EH_PE_absptr:
- break;
- case DW_EH_PE_pcrel:
- *val = (unsigned long) cur;
- break;
- default:
- return -EINVAL;
- }
-
- if ((encoding & 0x07) == 0x00)
- encoding |= DW_EH_PE_udata4;
-
- switch (encoding & DW_EH_PE_FORMAT_MASK) {
- case DW_EH_PE_sdata4:
- *val += dw_read(cur, s32, end);
- break;
- case DW_EH_PE_udata4:
- *val += dw_read(cur, u32, end);
- break;
- case DW_EH_PE_sdata8:
- *val += dw_read(cur, s64, end);
- break;
- case DW_EH_PE_udata8:
- *val += dw_read(cur, u64, end);
- break;
- default:
- return -EINVAL;
- }
-
- out:
- *p = cur;
- return 0;
-}
-
-#define dw_read_encoded_value(ptr, end, enc) ({ \
- u64 __v; \
- if (__dw_read_encoded_value(&ptr, end, &__v, enc)) { \
- return -EINVAL; \
- } \
- __v; \
- })
-
-static u64 elf_section_offset(int fd, const char *name)
-{
- Elf *elf;
- GElf_Ehdr ehdr;
- GElf_Shdr shdr;
- u64 offset = 0;
-
- elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
- if (elf == NULL)
- return 0;
-
- do {
- if (gelf_getehdr(elf, &ehdr) == NULL)
- break;
-
- if (!elf_section_by_name(elf, &ehdr, &shdr, name, NULL))
- break;
-
- offset = shdr.sh_offset;
- } while (0);
-
- elf_end(elf);
- return offset;
+ thread->unwind_libunwind_ops = ops;
}
-#ifndef NO_LIBUNWIND_DEBUG_FRAME
-static int elf_is_exec(int fd, const char *name)
+int unwind__prepare_access(struct thread *thread, struct map *map,
+ bool *initialized)
{
- Elf *elf;
- GElf_Ehdr ehdr;
- int retval = 0;
+ const char *arch;
+ enum dso_type dso_type;
+ struct unwind_libunwind_ops *ops = local_unwind_libunwind_ops;
+ int err;
- elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
- if (elf == NULL)
+ if (thread->addr_space) {
+ pr_debug("unwind: thread map already set, dso=%s\n",
+ map->dso->name);
+ if (initialized)
+ *initialized = true;
return 0;
- if (gelf_getehdr(elf, &ehdr) == NULL)
- goto out;
-
- retval = (ehdr.e_type == ET_EXEC);
-
-out:
- elf_end(elf);
- pr_debug("unwind: elf_is_exec(%s): %d\n", name, retval);
- return retval;
-}
-#endif
-
-struct table_entry {
- u32 start_ip_offset;
- u32 fde_offset;
-};
-
-struct eh_frame_hdr {
- unsigned char version;
- unsigned char eh_frame_ptr_enc;
- unsigned char fde_count_enc;
- unsigned char table_enc;
-
- /*
- * The rest of the header is variable-length and consists of the
- * following members:
- *
- * encoded_t eh_frame_ptr;
- * encoded_t fde_count;
- */
-
- /* A single encoded pointer should not be more than 8 bytes. */
- u64 enc[2];
-
- /*
- * struct {
- * encoded_t start_ip;
- * encoded_t fde_addr;
- * } binary_search_table[fde_count];
- */
- char data[0];
-} __packed;
-
-static int unwind_spec_ehframe(struct dso *dso, struct machine *machine,
- u64 offset, u64 *table_data, u64 *segbase,
- u64 *fde_count)
-{
- struct eh_frame_hdr hdr;
- u8 *enc = (u8 *) &hdr.enc;
- u8 *end = (u8 *) &hdr.data;
- ssize_t r;
-
- r = dso__data_read_offset(dso, machine, offset,
- (u8 *) &hdr, sizeof(hdr));
- if (r != sizeof(hdr))
- return -EINVAL;
-
- /* We dont need eh_frame_ptr, just skip it. */
- dw_read_encoded_value(enc, end, hdr.eh_frame_ptr_enc);
-
- *fde_count = dw_read_encoded_value(enc, end, hdr.fde_count_enc);
- *segbase = offset;
- *table_data = (enc - (u8 *) &hdr) + offset;
- return 0;
-}
-
-static int read_unwind_spec_eh_frame(struct dso *dso, struct machine *machine,
- u64 *table_data, u64 *segbase,
- u64 *fde_count)
-{
- int ret = -EINVAL, fd;
- u64 offset = dso->data.eh_frame_hdr_offset;
-
- if (offset == 0) {
- fd = dso__data_get_fd(dso, machine);
- if (fd < 0)
- return -EINVAL;
-
- /* Check the .eh_frame section for unwinding info */
- offset = elf_section_offset(fd, ".eh_frame_hdr");
- dso->data.eh_frame_hdr_offset = offset;
- dso__data_put_fd(dso);
}
- if (offset)
- ret = unwind_spec_ehframe(dso, machine, offset,
- table_data, segbase,
- fde_count);
+ /* env->arch is NULL for live-mode (i.e. perf top) */
+ if (!thread->mg->machine->env || !thread->mg->machine->env->arch)
+ goto out_register;
- return ret;
-}
-
-#ifndef NO_LIBUNWIND_DEBUG_FRAME
-static int read_unwind_spec_debug_frame(struct dso *dso,
- struct machine *machine, u64 *offset)
-{
- int fd;
- u64 ofs = dso->data.debug_frame_offset;
-
- if (ofs == 0) {
- fd = dso__data_get_fd(dso, machine);
- if (fd < 0)
- return -EINVAL;
-
- /* Check the .debug_frame section for unwinding info */
- ofs = elf_section_offset(fd, ".debug_frame");
- dso->data.debug_frame_offset = ofs;
- dso__data_put_fd(dso);
- }
-
- *offset = ofs;
- if (*offset)
+ dso_type = dso__type(map->dso, thread->mg->machine);
+ if (dso_type == DSO__TYPE_UNKNOWN)
return 0;
- return -EINVAL;
-}
-#endif
-
-static struct map *find_map(unw_word_t ip, struct unwind_info *ui)
-{
- struct addr_location al;
-
- thread__find_addr_map(ui->thread, PERF_RECORD_MISC_USER,
- MAP__FUNCTION, ip, &al);
- if (!al.map) {
- /*
- * We've seen cases (softice) where DWARF unwinder went
- * through non executable mmaps, which we need to lookup
- * in MAP__VARIABLE tree.
- */
- thread__find_addr_map(ui->thread, PERF_RECORD_MISC_USER,
- MAP__VARIABLE, ip, &al);
- }
- return al.map;
-}
-
-static int
-find_proc_info(unw_addr_space_t as, unw_word_t ip, unw_proc_info_t *pi,
- int need_unwind_info, void *arg)
-{
- struct unwind_info *ui = arg;
- struct map *map;
- unw_dyn_info_t di;
- u64 table_data, segbase, fde_count;
- int ret = -EINVAL;
-
- map = find_map(ip, ui);
- if (!map || !map->dso)
- return -EINVAL;
-
- pr_debug("unwind: find_proc_info dso %s\n", map->dso->name);
-
- /* Check the .eh_frame section for unwinding info */
- if (!read_unwind_spec_eh_frame(map->dso, ui->machine,
- &table_data, &segbase, &fde_count)) {
- memset(&di, 0, sizeof(di));
- di.format = UNW_INFO_FORMAT_REMOTE_TABLE;
- di.start_ip = map->start;
- di.end_ip = map->end;
- di.u.rti.segbase = map->start + segbase;
- di.u.rti.table_data = map->start + table_data;
- di.u.rti.table_len = fde_count * sizeof(struct table_entry)
- / sizeof(unw_word_t);
- ret = dwarf_search_unwind_table(as, ip, &di, pi,
- need_unwind_info, arg);
- }
-
-#ifndef NO_LIBUNWIND_DEBUG_FRAME
- /* Check the .debug_frame section for unwinding info */
- if (ret < 0 &&
- !read_unwind_spec_debug_frame(map->dso, ui->machine, &segbase)) {
- int fd = dso__data_get_fd(map->dso, ui->machine);
- int is_exec = elf_is_exec(fd, map->dso->name);
- unw_word_t base = is_exec ? 0 : map->start;
- const char *symfile;
-
- if (fd >= 0)
- dso__data_put_fd(map->dso);
-
- symfile = map->dso->symsrc_filename ?: map->dso->name;
-
- memset(&di, 0, sizeof(di));
- if (dwarf_find_debug_frame(0, &di, ip, base, symfile,
- map->start, map->end))
- return dwarf_search_unwind_table(as, ip, &di, pi,
- need_unwind_info, arg);
- }
-#endif
-
- return ret;
-}
-
-static int access_fpreg(unw_addr_space_t __maybe_unused as,
- unw_regnum_t __maybe_unused num,
- unw_fpreg_t __maybe_unused *val,
- int __maybe_unused __write,
- void __maybe_unused *arg)
-{
- pr_err("unwind: access_fpreg unsupported\n");
- return -UNW_EINVAL;
-}
-
-static int get_dyn_info_list_addr(unw_addr_space_t __maybe_unused as,
- unw_word_t __maybe_unused *dil_addr,
- void __maybe_unused *arg)
-{
- return -UNW_ENOINFO;
-}
-
-static int resume(unw_addr_space_t __maybe_unused as,
- unw_cursor_t __maybe_unused *cu,
- void __maybe_unused *arg)
-{
- pr_err("unwind: resume unsupported\n");
- return -UNW_EINVAL;
-}
+ arch = normalize_arch(thread->mg->machine->env->arch);
-static int
-get_proc_name(unw_addr_space_t __maybe_unused as,
- unw_word_t __maybe_unused addr,
- char __maybe_unused *bufp, size_t __maybe_unused buf_len,
- unw_word_t __maybe_unused *offp, void __maybe_unused *arg)
-{
- pr_err("unwind: get_proc_name unsupported\n");
- return -UNW_EINVAL;
-}
-
-static int access_dso_mem(struct unwind_info *ui, unw_word_t addr,
- unw_word_t *data)
-{
- struct map *map;
- ssize_t size;
-
- map = find_map(addr, ui);
- if (!map) {
- pr_debug("unwind: no map for %lx\n", (unsigned long)addr);
- return -1;
+ if (!strcmp(arch, "x86")) {
+ if (dso_type != DSO__TYPE_64BIT)
+ ops = x86_32_unwind_libunwind_ops;
+ } else if (!strcmp(arch, "arm64") || !strcmp(arch, "arm")) {
+ if (dso_type == DSO__TYPE_64BIT)
+ ops = arm64_unwind_libunwind_ops;
}
- if (!map->dso)
+ if (!ops) {
+ pr_err("unwind: target platform=%s is not supported\n", arch);
return -1;
-
- size = dso__data_read_addr(map->dso, map, ui->machine,
- addr, (u8 *) data, sizeof(*data));
-
- return !(size == sizeof(*data));
-}
-
-static int access_mem(unw_addr_space_t __maybe_unused as,
- unw_word_t addr, unw_word_t *valp,
- int __write, void *arg)
-{
- struct unwind_info *ui = arg;
- struct stack_dump *stack = &ui->sample->user_stack;
- u64 start, end;
- int offset;
- int ret;
-
- /* Don't support write, probably not needed. */
- if (__write || !stack || !ui->sample->user_regs.regs) {
- *valp = 0;
- return 0;
- }
-
- ret = perf_reg_value(&start, &ui->sample->user_regs, PERF_REG_SP);
- if (ret)
- return ret;
-
- end = start + stack->size;
-
- /* Check overflow. */
- if (addr + sizeof(unw_word_t) < addr)
- return -EINVAL;
-
- if (addr < start || addr + sizeof(unw_word_t) >= end) {
- ret = access_dso_mem(ui, addr, valp);
- if (ret) {
- pr_debug("unwind: access_mem %p not inside range"
- " 0x%" PRIx64 "-0x%" PRIx64 "\n",
- (void *) (uintptr_t) addr, start, end);
- *valp = 0;
- return ret;
- }
- return 0;
- }
-
- offset = addr - start;
- *valp = *(unw_word_t *)&stack->data[offset];
- pr_debug("unwind: access_mem addr %p val %lx, offset %d\n",
- (void *) (uintptr_t) addr, (unsigned long)*valp, offset);
- return 0;
-}
-
-static int access_reg(unw_addr_space_t __maybe_unused as,
- unw_regnum_t regnum, unw_word_t *valp,
- int __write, void *arg)
-{
- struct unwind_info *ui = arg;
- int id, ret;
- u64 val;
-
- /* Don't support write, I suspect we don't need it. */
- if (__write) {
- pr_err("unwind: access_reg w %d\n", regnum);
- return 0;
- }
-
- if (!ui->sample->user_regs.regs) {
- *valp = 0;
- return 0;
- }
-
- id = libunwind__arch_reg_id(regnum);
- if (id < 0)
- return -EINVAL;
-
- ret = perf_reg_value(&val, &ui->sample->user_regs, id);
- if (ret) {
- pr_err("unwind: can't read reg %d\n", regnum);
- return ret;
- }
-
- *valp = (unw_word_t) val;
- pr_debug("unwind: reg %d, val %lx\n", regnum, (unsigned long)*valp);
- return 0;
-}
-
-static void put_unwind_info(unw_addr_space_t __maybe_unused as,
- unw_proc_info_t *pi __maybe_unused,
- void *arg __maybe_unused)
-{
- pr_debug("unwind: put_unwind_info called\n");
-}
-
-static int entry(u64 ip, struct thread *thread,
- unwind_entry_cb_t cb, void *arg)
-{
- struct unwind_entry e;
- struct addr_location al;
-
- thread__find_addr_location(thread, PERF_RECORD_MISC_USER,
- MAP__FUNCTION, ip, &al);
-
- e.ip = ip;
- e.map = al.map;
- e.sym = al.sym;
-
- pr_debug("unwind: %s:ip = 0x%" PRIx64 " (0x%" PRIx64 ")\n",
- al.sym ? al.sym->name : "''",
- ip,
- al.map ? al.map->map_ip(al.map, ip) : (u64) 0);
-
- return cb(&e, arg);
-}
-
-static void display_error(int err)
-{
- switch (err) {
- case UNW_EINVAL:
- pr_err("unwind: Only supports local.\n");
- break;
- case UNW_EUNSPEC:
- pr_err("unwind: Unspecified error.\n");
- break;
- case UNW_EBADREG:
- pr_err("unwind: Register unavailable.\n");
- break;
- default:
- break;
- }
-}
-
-static unw_accessors_t accessors = {
- .find_proc_info = find_proc_info,
- .put_unwind_info = put_unwind_info,
- .get_dyn_info_list_addr = get_dyn_info_list_addr,
- .access_mem = access_mem,
- .access_reg = access_reg,
- .access_fpreg = access_fpreg,
- .resume = resume,
- .get_proc_name = get_proc_name,
-};
-
-int unwind__prepare_access(struct thread *thread)
-{
- if (callchain_param.record_mode != CALLCHAIN_DWARF)
- return 0;
-
- thread->addr_space = unw_create_addr_space(&accessors, 0);
- if (!thread->addr_space) {
- pr_err("unwind: Can't create unwind address space.\n");
- return -ENOMEM;
}
+out_register:
+ unwind__register_ops(thread, ops);
- unw_set_caching_policy(thread->addr_space, UNW_CACHE_GLOBAL);
- return 0;
+ err = thread->unwind_libunwind_ops->prepare_access(thread);
+ if (initialized)
+ *initialized = err ? false : true;
+ return err;
}
void unwind__flush_access(struct thread *thread)
{
- if (callchain_param.record_mode != CALLCHAIN_DWARF)
- return;
-
- unw_flush_cache(thread->addr_space, 0, 0);
+ if (thread->unwind_libunwind_ops)
+ thread->unwind_libunwind_ops->flush_access(thread);
}
void unwind__finish_access(struct thread *thread)
{
- if (callchain_param.record_mode != CALLCHAIN_DWARF)
- return;
-
- unw_destroy_addr_space(thread->addr_space);
-}
-
-static int get_entries(struct unwind_info *ui, unwind_entry_cb_t cb,
- void *arg, int max_stack)
-{
- u64 val;
- unw_word_t ips[max_stack];
- unw_addr_space_t addr_space;
- unw_cursor_t c;
- int ret, i = 0;
-
- ret = perf_reg_value(&val, &ui->sample->user_regs, PERF_REG_IP);
- if (ret)
- return ret;
-
- ips[i++] = (unw_word_t) val;
-
- /*
- * If we need more than one entry, do the DWARF
- * unwind itself.
- */
- if (max_stack - 1 > 0) {
- WARN_ONCE(!ui->thread, "WARNING: ui->thread is NULL");
- addr_space = ui->thread->addr_space;
-
- if (addr_space == NULL)
- return -1;
-
- ret = unw_init_remote(&c, addr_space, ui);
- if (ret)
- display_error(ret);
-
- while (!ret && (unw_step(&c) > 0) && i < max_stack) {
- unw_get_reg(&c, UNW_REG_IP, &ips[i]);
- ++i;
- }
-
- max_stack = i;
- }
-
- /*
- * Display what we got based on the order setup.
- */
- for (i = 0; i < max_stack && !ret; i++) {
- int j = i;
-
- if (callchain_param.order == ORDER_CALLER)
- j = max_stack - i - 1;
- ret = ips[j] ? entry(ips[j], ui->thread, cb, arg) : 0;
- }
-
- return ret;
+ if (thread->unwind_libunwind_ops)
+ thread->unwind_libunwind_ops->finish_access(thread);
}
int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
- struct thread *thread,
- struct perf_sample *data, int max_stack)
+ struct thread *thread,
+ struct perf_sample *data, int max_stack)
{
- struct unwind_info ui = {
- .sample = data,
- .thread = thread,
- .machine = thread->mg->machine,
- };
-
- if (!data->user_regs.regs)
- return -EINVAL;
-
- if (max_stack <= 0)
- return -EINVAL;
-
- return get_entries(&ui, cb, arg, max_stack);
+ if (thread->unwind_libunwind_ops)
+ return thread->unwind_libunwind_ops->get_entries(cb, arg, thread, data, max_stack);
+ return 0;
}
projects / cascardo / linux.git / blobdiff