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"
15 static char *debuginfo_path;
17 static const Dwfl_Callbacks offline_callbacks = {
18 .find_debuginfo = dwfl_standard_find_debuginfo,
19 .debuginfo_path = &debuginfo_path,
20 .section_address = dwfl_offline_section_address,
23 static int __report_module(struct addr_location *al, u64 ip,
24 struct unwind_info *ui)
27 struct dso *dso = NULL;
29 thread__find_addr_location(ui->thread,
30 PERF_RECORD_MISC_USER,
31 MAP__FUNCTION, ip, al);
39 mod = dwfl_addrmodule(ui->dwfl, ip);
41 mod = dwfl_report_elf(ui->dwfl, dso->short_name,
42 dso->long_name, -1, al->map->start,
45 return mod && dwfl_addrmodule(ui->dwfl, ip) == mod ? 0 : -1;
48 static int report_module(u64 ip, struct unwind_info *ui)
50 struct addr_location al;
52 return __report_module(&al, ip, ui);
55 static int entry(u64 ip, struct unwind_info *ui)
58 struct unwind_entry e;
59 struct addr_location al;
61 if (__report_module(&al, ip, ui))
68 pr_debug("unwind: %s:ip = 0x%" PRIx64 " (0x%" PRIx64 ")\n",
69 al.sym ? al.sym->name : "''",
71 al.map ? al.map->map_ip(al.map, ip) : (u64) 0);
73 return ui->cb(&e, ui->arg);
76 static pid_t next_thread(Dwfl *dwfl, void *arg, void **thread_argp)
78 /* We want only single thread to be processed. */
79 if (*thread_argp != NULL)
83 return dwfl_pid(dwfl);
86 static int access_dso_mem(struct unwind_info *ui, Dwarf_Addr addr,
89 struct addr_location al;
92 thread__find_addr_map(ui->thread, PERF_RECORD_MISC_USER,
93 MAP__FUNCTION, addr, &al);
95 pr_debug("unwind: no map for %lx\n", (unsigned long)addr);
102 size = dso__data_read_addr(al.map->dso, al.map, ui->machine,
103 addr, (u8 *) data, sizeof(*data));
105 return !(size == sizeof(*data));
108 static bool memory_read(Dwfl *dwfl __maybe_unused, Dwarf_Addr addr, Dwarf_Word *result,
111 struct unwind_info *ui = arg;
112 struct stack_dump *stack = &ui->sample->user_stack;
117 ret = perf_reg_value(&start, &ui->sample->user_regs, PERF_REG_SP);
121 end = start + stack->size;
123 /* Check overflow. */
124 if (addr + sizeof(Dwarf_Word) < addr)
127 if (addr < start || addr + sizeof(Dwarf_Word) > end) {
128 ret = access_dso_mem(ui, addr, result);
130 pr_debug("unwind: access_mem 0x%" PRIx64 " not inside range"
131 " 0x%" PRIx64 "-0x%" PRIx64 "\n",
138 offset = addr - start;
139 *result = *(Dwarf_Word *)&stack->data[offset];
140 pr_debug("unwind: access_mem addr 0x%" PRIx64 ", val %lx, offset %d\n",
141 addr, (unsigned long)*result, offset);
145 static const Dwfl_Thread_Callbacks callbacks = {
146 .next_thread = next_thread,
147 .memory_read = memory_read,
148 .set_initial_registers = libdw__arch_set_initial_registers,
152 frame_callback(Dwfl_Frame *state, void *arg)
154 struct unwind_info *ui = arg;
157 if (!dwfl_frame_pc(state, &pc, NULL)) {
158 pr_err("%s", dwfl_errmsg(-1));
159 return DWARF_CB_ABORT;
162 return entry(pc, ui) || !(--ui->max_stack) ?
163 DWARF_CB_ABORT : DWARF_CB_OK;
166 int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
167 struct thread *thread,
168 struct perf_sample *data,
171 struct unwind_info ui = {
174 .machine = thread->mg->machine,
177 .max_stack = max_stack,
182 if (!data->user_regs.regs)
185 ui.dwfl = dwfl_begin(&offline_callbacks);
189 err = perf_reg_value(&ip, &data->user_regs, PERF_REG_IP);
193 err = report_module(ip, &ui);
197 if (!dwfl_attach_state(ui.dwfl, EM_NONE, thread->tid, &callbacks, &ui))
200 err = dwfl_getthread_frames(ui.dwfl, thread->tid, frame_callback, &ui);
202 if (err && !ui.max_stack)
207 pr_debug("unwind: failed with '%s'\n", dwfl_errmsg(-1));