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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /tools/perf/util/unwind-libdw.c | |
parent | Initial commit. (diff) | |
download | linux-430c2fc249ea5c0536abd21c23382884005c9093.tar.xz linux-430c2fc249ea5c0536abd21c23382884005c9093.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tools/perf/util/unwind-libdw.c')
-rw-r--r-- | tools/perf/util/unwind-libdw.c | 287 |
1 files changed, 287 insertions, 0 deletions
diff --git a/tools/perf/util/unwind-libdw.c b/tools/perf/util/unwind-libdw.c new file mode 100644 index 000000000..a74b517f7 --- /dev/null +++ b/tools/perf/util/unwind-libdw.c @@ -0,0 +1,287 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/compiler.h> +#include <elfutils/libdw.h> +#include <elfutils/libdwfl.h> +#include <inttypes.h> +#include <errno.h> +#include "debug.h" +#include "dso.h" +#include "unwind.h" +#include "unwind-libdw.h" +#include "machine.h" +#include "map.h" +#include "symbol.h" +#include "thread.h" +#include <linux/types.h> +#include <linux/zalloc.h> +#include "event.h" +#include "perf_regs.h" +#include "callchain.h" + +static char *debuginfo_path; + +static int __find_debuginfo(Dwfl_Module *mod __maybe_unused, void **userdata, + const char *modname __maybe_unused, Dwarf_Addr base __maybe_unused, + const char *file_name, const char *debuglink_file __maybe_unused, + GElf_Word debuglink_crc __maybe_unused, char **debuginfo_file_name) +{ + const struct dso *dso = *userdata; + + assert(dso); + if (dso->symsrc_filename && strcmp (file_name, dso->symsrc_filename)) + *debuginfo_file_name = strdup(dso->symsrc_filename); + return -1; +} + +static const Dwfl_Callbacks offline_callbacks = { + .find_debuginfo = __find_debuginfo, + .debuginfo_path = &debuginfo_path, + .section_address = dwfl_offline_section_address, + // .find_elf is not set as we use dwfl_report_elf() instead. +}; + +static int __report_module(struct addr_location *al, u64 ip, + struct unwind_info *ui) +{ + Dwfl_Module *mod; + struct dso *dso = NULL; + /* + * Some callers will use al->sym, so we can't just use the + * cheaper thread__find_map() here. + */ + thread__find_symbol(ui->thread, PERF_RECORD_MISC_USER, ip, al); + + if (al->map) + dso = al->map->dso; + + if (!dso) + return 0; + + mod = dwfl_addrmodule(ui->dwfl, ip); + if (mod) { + Dwarf_Addr s; + + dwfl_module_info(mod, NULL, &s, NULL, NULL, NULL, NULL, NULL); + if (s != al->map->start - al->map->pgoff) + mod = 0; + } + + if (!mod) + mod = dwfl_report_elf(ui->dwfl, dso->short_name, dso->long_name, -1, + al->map->start - al->map->pgoff, false); + if (!mod) { + char filename[PATH_MAX]; + + if (dso__build_id_filename(dso, filename, sizeof(filename), false)) + mod = dwfl_report_elf(ui->dwfl, dso->short_name, filename, -1, + al->map->start - al->map->pgoff, false); + } + + if (mod) { + void **userdatap; + + dwfl_module_info(mod, &userdatap, NULL, NULL, NULL, NULL, NULL, NULL); + *userdatap = dso; + } + + return mod && dwfl_addrmodule(ui->dwfl, ip) == mod ? 0 : -1; +} + +static int report_module(u64 ip, struct unwind_info *ui) +{ + struct addr_location al; + + return __report_module(&al, ip, ui); +} + +/* + * Store all entries within entries array, + * we will process it after we finish unwind. + */ +static int entry(u64 ip, struct unwind_info *ui) + +{ + struct unwind_entry *e = &ui->entries[ui->idx++]; + struct addr_location al; + + if (__report_module(&al, ip, ui)) + return -1; + + e->ip = ip; + e->ms.maps = al.maps; + e->ms.map = al.map; + e->ms.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 0; +} + +static pid_t next_thread(Dwfl *dwfl, void *arg, void **thread_argp) +{ + /* We want only single thread to be processed. */ + if (*thread_argp != NULL) + return 0; + + *thread_argp = arg; + return dwfl_pid(dwfl); +} + +static int access_dso_mem(struct unwind_info *ui, Dwarf_Addr addr, + Dwarf_Word *data) +{ + struct addr_location al; + ssize_t size; + + if (!thread__find_map(ui->thread, PERF_RECORD_MISC_USER, addr, &al)) { + pr_debug("unwind: no map for %lx\n", (unsigned long)addr); + return -1; + } + + if (!al.map->dso) + return -1; + + size = dso__data_read_addr(al.map->dso, al.map, ui->machine, + addr, (u8 *) data, sizeof(*data)); + + return !(size == sizeof(*data)); +} + +static bool memory_read(Dwfl *dwfl __maybe_unused, Dwarf_Addr addr, Dwarf_Word *result, + void *arg) +{ + struct unwind_info *ui = arg; + struct stack_dump *stack = &ui->sample->user_stack; + u64 start, end; + int offset; + int ret; + + ret = perf_reg_value(&start, &ui->sample->user_regs, PERF_REG_SP); + if (ret) + return false; + + end = start + stack->size; + + /* Check overflow. */ + if (addr + sizeof(Dwarf_Word) < addr) + return false; + + if (addr < start || addr + sizeof(Dwarf_Word) > end) { + ret = access_dso_mem(ui, addr, result); + if (ret) { + pr_debug("unwind: access_mem 0x%" PRIx64 " not inside range" + " 0x%" PRIx64 "-0x%" PRIx64 "\n", + addr, start, end); + return false; + } + return true; + } + + offset = addr - start; + *result = *(Dwarf_Word *)&stack->data[offset]; + pr_debug("unwind: access_mem addr 0x%" PRIx64 ", val %lx, offset %d\n", + addr, (unsigned long)*result, offset); + return true; +} + +static const Dwfl_Thread_Callbacks callbacks = { + .next_thread = next_thread, + .memory_read = memory_read, + .set_initial_registers = libdw__arch_set_initial_registers, +}; + +static int +frame_callback(Dwfl_Frame *state, void *arg) +{ + struct unwind_info *ui = arg; + Dwarf_Addr pc; + bool isactivation; + + if (!dwfl_frame_pc(state, &pc, NULL)) { + pr_err("%s", dwfl_errmsg(-1)); + return DWARF_CB_ABORT; + } + + // report the module before we query for isactivation + report_module(pc, ui); + + if (!dwfl_frame_pc(state, &pc, &isactivation)) { + pr_err("%s", dwfl_errmsg(-1)); + return DWARF_CB_ABORT; + } + + if (!isactivation) + --pc; + + return entry(pc, ui) || !(--ui->max_stack) ? + DWARF_CB_ABORT : DWARF_CB_OK; +} + +int unwind__get_entries(unwind_entry_cb_t cb, void *arg, + struct thread *thread, + struct perf_sample *data, + int max_stack) +{ + struct unwind_info *ui, ui_buf = { + .sample = data, + .thread = thread, + .machine = thread->maps->machine, + .cb = cb, + .arg = arg, + .max_stack = max_stack, + }; + Dwarf_Word ip; + int err = -EINVAL, i; + + if (!data->user_regs.regs) + return -EINVAL; + + ui = zalloc(sizeof(ui_buf) + sizeof(ui_buf.entries[0]) * max_stack); + if (!ui) + return -ENOMEM; + + *ui = ui_buf; + + ui->dwfl = dwfl_begin(&offline_callbacks); + if (!ui->dwfl) + goto out; + + err = perf_reg_value(&ip, &data->user_regs, PERF_REG_IP); + if (err) + goto out; + + err = report_module(ip, ui); + if (err) + goto out; + + err = !dwfl_attach_state(ui->dwfl, EM_NONE, thread->tid, &callbacks, ui); + if (err) + goto out; + + err = dwfl_getthread_frames(ui->dwfl, thread->tid, frame_callback, ui); + + if (err && ui->max_stack != max_stack) + err = 0; + + /* + * Display what we got based on the order setup. + */ + for (i = 0; i < ui->idx && !err; i++) { + int j = i; + + if (callchain_param.order == ORDER_CALLER) + j = ui->idx - i - 1; + + err = ui->entries[j].ip ? ui->cb(&ui->entries[j], ui->arg) : 0; + } + + out: + if (err) + pr_debug("unwind: failed with '%s'\n", dwfl_errmsg(-1)); + + dwfl_end(ui->dwfl); + free(ui); + return 0; +} |