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287 lines
6.4 KiB
287 lines
6.4 KiB
// SPDX-License-Identifier: GPL-2.0 |
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#include <linux/compiler.h> |
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#include <elfutils/libdw.h> |
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#include <elfutils/libdwfl.h> |
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#include <inttypes.h> |
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#include <errno.h> |
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#include "debug.h" |
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#include "dso.h" |
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#include "unwind.h" |
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#include "unwind-libdw.h" |
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#include "machine.h" |
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#include "map.h" |
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#include "symbol.h" |
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#include "thread.h" |
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#include <linux/types.h> |
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#include <linux/zalloc.h> |
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#include "event.h" |
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#include "perf_regs.h" |
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#include "callchain.h" |
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static char *debuginfo_path; |
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static int __find_debuginfo(Dwfl_Module *mod __maybe_unused, void **userdata, |
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const char *modname __maybe_unused, Dwarf_Addr base __maybe_unused, |
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const char *file_name, const char *debuglink_file __maybe_unused, |
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GElf_Word debuglink_crc __maybe_unused, char **debuginfo_file_name) |
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{ |
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const struct dso *dso = *userdata; |
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assert(dso); |
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if (dso->symsrc_filename && strcmp (file_name, dso->symsrc_filename)) |
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*debuginfo_file_name = strdup(dso->symsrc_filename); |
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return -1; |
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} |
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static const Dwfl_Callbacks offline_callbacks = { |
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.find_debuginfo = __find_debuginfo, |
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.debuginfo_path = &debuginfo_path, |
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.section_address = dwfl_offline_section_address, |
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// .find_elf is not set as we use dwfl_report_elf() instead. |
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}; |
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static int __report_module(struct addr_location *al, u64 ip, |
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struct unwind_info *ui) |
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{ |
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Dwfl_Module *mod; |
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struct dso *dso = NULL; |
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/* |
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* Some callers will use al->sym, so we can't just use the |
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* cheaper thread__find_map() here. |
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*/ |
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thread__find_symbol(ui->thread, PERF_RECORD_MISC_USER, ip, al); |
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if (al->map) |
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dso = al->map->dso; |
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if (!dso) |
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return 0; |
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mod = dwfl_addrmodule(ui->dwfl, ip); |
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if (mod) { |
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Dwarf_Addr s; |
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dwfl_module_info(mod, NULL, &s, NULL, NULL, NULL, NULL, NULL); |
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if (s != al->map->start - al->map->pgoff) |
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mod = 0; |
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} |
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if (!mod) |
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mod = dwfl_report_elf(ui->dwfl, dso->short_name, dso->long_name, -1, |
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al->map->start - al->map->pgoff, false); |
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if (!mod) { |
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char filename[PATH_MAX]; |
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if (dso__build_id_filename(dso, filename, sizeof(filename), false)) |
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mod = dwfl_report_elf(ui->dwfl, dso->short_name, filename, -1, |
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al->map->start - al->map->pgoff, false); |
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} |
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if (mod) { |
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void **userdatap; |
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dwfl_module_info(mod, &userdatap, NULL, NULL, NULL, NULL, NULL, NULL); |
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*userdatap = dso; |
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} |
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return mod && dwfl_addrmodule(ui->dwfl, ip) == mod ? 0 : -1; |
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} |
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static int report_module(u64 ip, struct unwind_info *ui) |
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{ |
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struct addr_location al; |
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return __report_module(&al, ip, ui); |
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} |
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/* |
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* Store all entries within entries array, |
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* we will process it after we finish unwind. |
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*/ |
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static int entry(u64 ip, struct unwind_info *ui) |
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{ |
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struct unwind_entry *e = &ui->entries[ui->idx++]; |
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struct addr_location al; |
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if (__report_module(&al, ip, ui)) |
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return -1; |
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e->ip = ip; |
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e->ms.maps = al.maps; |
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e->ms.map = al.map; |
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e->ms.sym = al.sym; |
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pr_debug("unwind: %s:ip = 0x%" PRIx64 " (0x%" PRIx64 ")\n", |
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al.sym ? al.sym->name : "''", |
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ip, |
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al.map ? al.map->map_ip(al.map, ip) : (u64) 0); |
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return 0; |
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} |
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static pid_t next_thread(Dwfl *dwfl, void *arg, void **thread_argp) |
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{ |
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/* We want only single thread to be processed. */ |
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if (*thread_argp != NULL) |
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return 0; |
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*thread_argp = arg; |
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return dwfl_pid(dwfl); |
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} |
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static int access_dso_mem(struct unwind_info *ui, Dwarf_Addr addr, |
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Dwarf_Word *data) |
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{ |
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struct addr_location al; |
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ssize_t size; |
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if (!thread__find_map(ui->thread, PERF_RECORD_MISC_USER, addr, &al)) { |
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pr_debug("unwind: no map for %lx\n", (unsigned long)addr); |
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return -1; |
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} |
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if (!al.map->dso) |
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return -1; |
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size = dso__data_read_addr(al.map->dso, al.map, ui->machine, |
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addr, (u8 *) data, sizeof(*data)); |
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return !(size == sizeof(*data)); |
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} |
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static bool memory_read(Dwfl *dwfl __maybe_unused, Dwarf_Addr addr, Dwarf_Word *result, |
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void *arg) |
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{ |
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struct unwind_info *ui = arg; |
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struct stack_dump *stack = &ui->sample->user_stack; |
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u64 start, end; |
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int offset; |
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int ret; |
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ret = perf_reg_value(&start, &ui->sample->user_regs, PERF_REG_SP); |
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if (ret) |
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return false; |
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end = start + stack->size; |
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/* Check overflow. */ |
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if (addr + sizeof(Dwarf_Word) < addr) |
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return false; |
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if (addr < start || addr + sizeof(Dwarf_Word) > end) { |
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ret = access_dso_mem(ui, addr, result); |
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if (ret) { |
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pr_debug("unwind: access_mem 0x%" PRIx64 " not inside range" |
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" 0x%" PRIx64 "-0x%" PRIx64 "\n", |
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addr, start, end); |
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return false; |
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} |
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return true; |
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} |
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offset = addr - start; |
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*result = *(Dwarf_Word *)&stack->data[offset]; |
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pr_debug("unwind: access_mem addr 0x%" PRIx64 ", val %lx, offset %d\n", |
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addr, (unsigned long)*result, offset); |
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return true; |
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} |
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static const Dwfl_Thread_Callbacks callbacks = { |
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.next_thread = next_thread, |
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.memory_read = memory_read, |
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.set_initial_registers = libdw__arch_set_initial_registers, |
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}; |
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static int |
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frame_callback(Dwfl_Frame *state, void *arg) |
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{ |
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struct unwind_info *ui = arg; |
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Dwarf_Addr pc; |
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bool isactivation; |
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if (!dwfl_frame_pc(state, &pc, NULL)) { |
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pr_err("%s", dwfl_errmsg(-1)); |
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return DWARF_CB_ABORT; |
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} |
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// report the module before we query for isactivation |
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report_module(pc, ui); |
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if (!dwfl_frame_pc(state, &pc, &isactivation)) { |
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pr_err("%s", dwfl_errmsg(-1)); |
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return DWARF_CB_ABORT; |
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} |
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if (!isactivation) |
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--pc; |
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return entry(pc, ui) || !(--ui->max_stack) ? |
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DWARF_CB_ABORT : DWARF_CB_OK; |
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} |
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int unwind__get_entries(unwind_entry_cb_t cb, void *arg, |
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struct thread *thread, |
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struct perf_sample *data, |
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int max_stack) |
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{ |
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struct unwind_info *ui, ui_buf = { |
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.sample = data, |
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.thread = thread, |
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.machine = thread->maps->machine, |
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.cb = cb, |
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.arg = arg, |
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.max_stack = max_stack, |
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}; |
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Dwarf_Word ip; |
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int err = -EINVAL, i; |
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if (!data->user_regs.regs) |
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return -EINVAL; |
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ui = zalloc(sizeof(ui_buf) + sizeof(ui_buf.entries[0]) * max_stack); |
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if (!ui) |
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return -ENOMEM; |
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*ui = ui_buf; |
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ui->dwfl = dwfl_begin(&offline_callbacks); |
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if (!ui->dwfl) |
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goto out; |
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err = perf_reg_value(&ip, &data->user_regs, PERF_REG_IP); |
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if (err) |
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goto out; |
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err = report_module(ip, ui); |
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if (err) |
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goto out; |
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err = !dwfl_attach_state(ui->dwfl, EM_NONE, thread->tid, &callbacks, ui); |
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if (err) |
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goto out; |
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err = dwfl_getthread_frames(ui->dwfl, thread->tid, frame_callback, ui); |
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if (err && ui->max_stack != max_stack) |
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err = 0; |
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/* |
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* Display what we got based on the order setup. |
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*/ |
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for (i = 0; i < ui->idx && !err; i++) { |
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int j = i; |
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if (callchain_param.order == ORDER_CALLER) |
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j = ui->idx - i - 1; |
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err = ui->entries[j].ip ? ui->cb(&ui->entries[j], ui->arg) : 0; |
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} |
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out: |
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if (err) |
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pr_debug("unwind: failed with '%s'\n", dwfl_errmsg(-1)); |
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dwfl_end(ui->dwfl); |
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free(ui); |
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return 0; |
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}
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