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"
17 static char *debuginfo_path;
19 static const Dwfl_Callbacks offline_callbacks = {
20 .find_debuginfo = dwfl_standard_find_debuginfo,
21 .debuginfo_path = &debuginfo_path,
22 .section_address = dwfl_offline_section_address,
25 static int __report_module(struct addr_location *al, u64 ip,
26 struct unwind_info *ui)
29 struct dso *dso = NULL;
31 thread__find_addr_location(ui->thread,
32 PERF_RECORD_MISC_USER,
33 MAP__FUNCTION, ip, al);
41 mod = dwfl_addrmodule(ui->dwfl, ip);
45 dwfl_module_info(mod, NULL, &s, NULL, NULL, NULL, NULL, NULL);
46 if (s != al->map->start)
51 mod = dwfl_report_elf(ui->dwfl, dso->short_name,
52 dso->long_name, -1, al->map->start,
55 return mod && dwfl_addrmodule(ui->dwfl, ip) == mod ? 0 : -1;
58 static int report_module(u64 ip, struct unwind_info *ui)
60 struct addr_location al;
62 return __report_module(&al, ip, ui);
66 * Store all entries within entries array,
67 * we will process it after we finish unwind.
69 static int entry(u64 ip, struct unwind_info *ui)
72 struct unwind_entry *e = &ui->entries[ui->idx++];
73 struct addr_location al;
75 if (__report_module(&al, ip, ui))
82 pr_debug("unwind: %s:ip = 0x%" PRIx64 " (0x%" PRIx64 ")\n",
83 al.sym ? al.sym->name : "''",
85 al.map ? al.map->map_ip(al.map, ip) : (u64) 0);
89 static pid_t next_thread(Dwfl *dwfl, void *arg, void **thread_argp)
91 /* We want only single thread to be processed. */
92 if (*thread_argp != NULL)
96 return dwfl_pid(dwfl);
99 static int access_dso_mem(struct unwind_info *ui, Dwarf_Addr addr,
102 struct addr_location al;
105 thread__find_addr_map(ui->thread, PERF_RECORD_MISC_USER,
106 MAP__FUNCTION, addr, &al);
109 * We've seen cases (softice) where DWARF unwinder went
110 * through non executable mmaps, which we need to lookup
111 * in MAP__VARIABLE tree.
113 thread__find_addr_map(ui->thread, PERF_RECORD_MISC_USER,
114 MAP__VARIABLE, addr, &al);
118 pr_debug("unwind: no map for %lx\n", (unsigned long)addr);
125 size = dso__data_read_addr(al.map->dso, al.map, ui->machine,
126 addr, (u8 *) data, sizeof(*data));
128 return !(size == sizeof(*data));
131 static bool memory_read(Dwfl *dwfl __maybe_unused, Dwarf_Addr addr, Dwarf_Word *result,
134 struct unwind_info *ui = arg;
135 struct stack_dump *stack = &ui->sample->user_stack;
140 ret = perf_reg_value(&start, &ui->sample->user_regs, PERF_REG_SP);
144 end = start + stack->size;
146 /* Check overflow. */
147 if (addr + sizeof(Dwarf_Word) < addr)
150 if (addr < start || addr + sizeof(Dwarf_Word) > end) {
151 ret = access_dso_mem(ui, addr, result);
153 pr_debug("unwind: access_mem 0x%" PRIx64 " not inside range"
154 " 0x%" PRIx64 "-0x%" PRIx64 "\n",
161 offset = addr - start;
162 *result = *(Dwarf_Word *)&stack->data[offset];
163 pr_debug("unwind: access_mem addr 0x%" PRIx64 ", val %lx, offset %d\n",
164 addr, (unsigned long)*result, offset);
168 static const Dwfl_Thread_Callbacks callbacks = {
169 .next_thread = next_thread,
170 .memory_read = memory_read,
171 .set_initial_registers = libdw__arch_set_initial_registers,
175 frame_callback(Dwfl_Frame *state, void *arg)
177 struct unwind_info *ui = arg;
181 if (!dwfl_frame_pc(state, &pc, &isactivation)) {
182 pr_err("%s", dwfl_errmsg(-1));
183 return DWARF_CB_ABORT;
189 return entry(pc, ui) || !(--ui->max_stack) ?
190 DWARF_CB_ABORT : DWARF_CB_OK;
193 int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
194 struct thread *thread,
195 struct perf_sample *data,
198 struct unwind_info *ui, ui_buf = {
201 .machine = thread->mg->machine,
204 .max_stack = max_stack,
207 int err = -EINVAL, i;
209 if (!data->user_regs.regs)
212 ui = zalloc(sizeof(ui_buf) + sizeof(ui_buf.entries[0]) * max_stack);
218 ui->dwfl = dwfl_begin(&offline_callbacks);
222 err = perf_reg_value(&ip, &data->user_regs, PERF_REG_IP);
226 err = report_module(ip, ui);
230 if (!dwfl_attach_state(ui->dwfl, EM_NONE, thread->tid, &callbacks, ui))
233 err = dwfl_getthread_frames(ui->dwfl, thread->tid, frame_callback, ui);
235 if (err && ui->max_stack != max_stack)
239 * Display what we got based on the order setup.
241 for (i = 0; i < ui->idx && !err; i++) {
244 if (callchain_param.order == ORDER_CALLER)
247 err = ui->entries[j].ip ? ui->cb(&ui->entries[j], ui->arg) : 0;
252 pr_debug("unwind: failed with '%s'\n", dwfl_errmsg(-1));