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);
43 dwfl_module_info(mod, NULL, &s, NULL, NULL, NULL, NULL, NULL);
44 if (s != al->map->start - al->map->pgoff)
49 mod = dwfl_report_elf(ui->dwfl, dso->short_name,
50 (dso->symsrc_filename ? dso->symsrc_filename : dso->long_name), -1, al->map->start - al->map->pgoff,
53 return mod && dwfl_addrmodule(ui->dwfl, ip) == mod ? 0 : -1;
56 static int report_module(u64 ip, struct unwind_info *ui)
58 struct addr_location al;
60 return __report_module(&al, ip, ui);
63 static int entry(u64 ip, struct unwind_info *ui)
66 struct unwind_entry e;
67 struct addr_location al;
69 if (__report_module(&al, ip, ui))
76 pr_debug("unwind: %s:ip = 0x%" PRIx64 " (0x%" PRIx64 ")\n",
77 al.sym ? al.sym->name : "''",
79 al.map ? al.map->map_ip(al.map, ip) : (u64) 0);
81 return ui->cb(&e, ui->arg);
84 static pid_t next_thread(Dwfl *dwfl, void *arg, void **thread_argp)
86 /* We want only single thread to be processed. */
87 if (*thread_argp != NULL)
91 return dwfl_pid(dwfl);
94 static int access_dso_mem(struct unwind_info *ui, Dwarf_Addr addr,
97 struct addr_location al;
100 thread__find_addr_map(ui->thread, PERF_RECORD_MISC_USER,
101 MAP__FUNCTION, addr, &al);
103 pr_debug("unwind: no map for %lx\n", (unsigned long)addr);
110 size = dso__data_read_addr(al.map->dso, al.map, ui->machine,
111 addr, (u8 *) data, sizeof(*data));
113 return !(size == sizeof(*data));
116 static bool memory_read(Dwfl *dwfl __maybe_unused, Dwarf_Addr addr, Dwarf_Word *result,
119 struct unwind_info *ui = arg;
120 struct stack_dump *stack = &ui->sample->user_stack;
125 ret = perf_reg_value(&start, &ui->sample->user_regs, PERF_REG_SP);
129 end = start + stack->size;
131 /* Check overflow. */
132 if (addr + sizeof(Dwarf_Word) < addr)
135 if (addr < start || addr + sizeof(Dwarf_Word) > end) {
136 ret = access_dso_mem(ui, addr, result);
138 pr_debug("unwind: access_mem 0x%" PRIx64 " not inside range"
139 " 0x%" PRIx64 "-0x%" PRIx64 "\n",
146 offset = addr - start;
147 *result = *(Dwarf_Word *)&stack->data[offset];
148 pr_debug("unwind: access_mem addr 0x%" PRIx64 ", val %lx, offset %d\n",
149 addr, (unsigned long)*result, offset);
153 static const Dwfl_Thread_Callbacks callbacks = {
154 .next_thread = next_thread,
155 .memory_read = memory_read,
156 .set_initial_registers = libdw__arch_set_initial_registers,
160 frame_callback(Dwfl_Frame *state, void *arg)
162 struct unwind_info *ui = arg;
165 if (!dwfl_frame_pc(state, &pc, NULL)) {
166 pr_err("%s", dwfl_errmsg(-1));
167 return DWARF_CB_ABORT;
170 return entry(pc, ui) || !(--ui->max_stack) ?
171 DWARF_CB_ABORT : DWARF_CB_OK;
174 int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
175 struct thread *thread,
176 struct perf_sample *data,
179 struct unwind_info ui = {
182 .machine = thread->mg->machine,
185 .max_stack = max_stack,
190 if (!data->user_regs.regs)
193 ui.dwfl = dwfl_begin(&offline_callbacks);
197 err = perf_reg_value(&ip, &data->user_regs, PERF_REG_IP);
201 err = report_module(ip, &ui);
205 if (!dwfl_attach_state(ui.dwfl, EM_NONE, thread->tid, &callbacks, &ui))
208 err = dwfl_getthread_frames(ui.dwfl, thread->tid, frame_callback, &ui);
210 if (err && !ui.max_stack)
215 pr_debug("unwind: failed with '%s'\n", dwfl_errmsg(-1));