1 #include <linux/compiler.h>
2 #include <elfutils/libdw.h>
3 #include <elfutils/libdwfl.h>
8 #include "unwind-libdw.h"
11 #include <linux/types.h>
13 #include "perf_regs.h"
14 #include "callchain.h"
16 static char *debuginfo_path;
18 static const Dwfl_Callbacks offline_callbacks = {
19 .find_debuginfo = dwfl_standard_find_debuginfo,
20 .debuginfo_path = &debuginfo_path,
21 .section_address = dwfl_offline_section_address,
24 static int __report_module(struct addr_location *al, u64 ip,
25 struct unwind_info *ui)
28 struct dso *dso = NULL;
30 thread__find_addr_location(ui->thread,
31 PERF_RECORD_MISC_USER,
32 MAP__FUNCTION, ip, al);
40 mod = dwfl_addrmodule(ui->dwfl, ip);
44 dwfl_module_info(mod, NULL, &s, NULL, NULL, NULL, NULL, NULL);
45 if (s != al->map->start - al->map->pgoff)
50 mod = dwfl_report_elf(ui->dwfl, dso->short_name,
51 (dso->symsrc_filename ? dso->symsrc_filename : dso->long_name), -1, al->map->start - al->map->pgoff,
54 return mod && dwfl_addrmodule(ui->dwfl, ip) == mod ? 0 : -1;
57 static int report_module(u64 ip, struct unwind_info *ui)
59 struct addr_location al;
61 return __report_module(&al, ip, ui);
65 * Store all entries within entries array,
66 * we will process it after we finish unwind.
68 static int entry(u64 ip, struct unwind_info *ui)
71 struct unwind_entry *e = &ui->entries[ui->idx++];
72 struct addr_location al;
74 if (__report_module(&al, ip, ui))
81 pr_debug("unwind: %s:ip = 0x%" PRIx64 " (0x%" PRIx64 ")\n",
82 al.sym ? al.sym->name : "''",
84 al.map ? al.map->map_ip(al.map, ip) : (u64) 0);
88 static pid_t next_thread(Dwfl *dwfl, void *arg, void **thread_argp)
90 /* We want only single thread to be processed. */
91 if (*thread_argp != NULL)
95 return dwfl_pid(dwfl);
98 static int access_dso_mem(struct unwind_info *ui, Dwarf_Addr addr,
101 struct addr_location al;
104 thread__find_addr_map(ui->thread, PERF_RECORD_MISC_USER,
105 MAP__FUNCTION, addr, &al);
108 * We've seen cases (softice) where DWARF unwinder went
109 * through non executable mmaps, which we need to lookup
110 * in MAP__VARIABLE tree.
112 thread__find_addr_map(ui->thread, PERF_RECORD_MISC_USER,
113 MAP__VARIABLE, addr, &al);
117 pr_debug("unwind: no map for %lx\n", (unsigned long)addr);
124 size = dso__data_read_addr(al.map->dso, al.map, ui->machine,
125 addr, (u8 *) data, sizeof(*data));
127 return !(size == sizeof(*data));
130 static bool memory_read(Dwfl *dwfl __maybe_unused, Dwarf_Addr addr, Dwarf_Word *result,
133 struct unwind_info *ui = arg;
134 struct stack_dump *stack = &ui->sample->user_stack;
139 ret = perf_reg_value(&start, &ui->sample->user_regs, PERF_REG_SP);
143 end = start + stack->size;
145 /* Check overflow. */
146 if (addr + sizeof(Dwarf_Word) < addr)
149 if (addr < start || addr + sizeof(Dwarf_Word) > end) {
150 ret = access_dso_mem(ui, addr, result);
152 pr_debug("unwind: access_mem 0x%" PRIx64 " not inside range"
153 " 0x%" PRIx64 "-0x%" PRIx64 "\n",
160 offset = addr - start;
161 *result = *(Dwarf_Word *)&stack->data[offset];
162 pr_debug("unwind: access_mem addr 0x%" PRIx64 ", val %lx, offset %d\n",
163 addr, (unsigned long)*result, offset);
167 static const Dwfl_Thread_Callbacks callbacks = {
168 .next_thread = next_thread,
169 .memory_read = memory_read,
170 .set_initial_registers = libdw__arch_set_initial_registers,
174 frame_callback(Dwfl_Frame *state, void *arg)
176 struct unwind_info *ui = arg;
180 if (!dwfl_frame_pc(state, &pc, &isactivation)) {
181 pr_err("%s", dwfl_errmsg(-1));
182 return DWARF_CB_ABORT;
188 return entry(pc, ui) || !(--ui->max_stack) ?
189 DWARF_CB_ABORT : DWARF_CB_OK;
192 int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
193 struct thread *thread,
194 struct perf_sample *data,
197 struct unwind_info *ui, ui_buf = {
200 .machine = thread->mg->machine,
203 .max_stack = max_stack,
206 int err = -EINVAL, i;
208 if (!data->user_regs.regs)
211 ui = zalloc(sizeof(ui_buf) + sizeof(ui_buf.entries[0]) * max_stack);
217 ui->dwfl = dwfl_begin(&offline_callbacks);
221 err = perf_reg_value(&ip, &data->user_regs, PERF_REG_IP);
225 err = report_module(ip, ui);
229 if (!dwfl_attach_state(ui->dwfl, EM_NONE, thread->tid, &callbacks, ui))
232 err = dwfl_getthread_frames(ui->dwfl, thread->tid, frame_callback, ui);
234 if (err && ui->max_stack != max_stack)
238 * Display what we got based on the order setup.
240 for (i = 0; i < ui->idx && !err; i++) {
243 if (callchain_param.order == ORDER_CALLER)
246 err = ui->entries[j].ip ? ui->cb(&ui->entries[j], ui->arg) : 0;
251 pr_debug("unwind: failed with '%s'\n", dwfl_errmsg(-1));