1 #include <linux/compiler.h>
2 #include <elfutils/libdw.h>
3 #include <elfutils/libdwfl.h>
7 #include "unwind-libdw.h"
10 #include <linux/types.h>
12 #include "perf_regs.h"
14 static char *debuginfo_path;
16 static const Dwfl_Callbacks offline_callbacks = {
17 .find_debuginfo = dwfl_standard_find_debuginfo,
18 .debuginfo_path = &debuginfo_path,
19 .section_address = dwfl_offline_section_address,
22 static int __report_module(struct addr_location *al, u64 ip,
23 struct unwind_info *ui)
26 struct dso *dso = NULL;
28 thread__find_addr_location(ui->thread, ui->machine,
29 PERF_RECORD_MISC_USER,
30 MAP__FUNCTION, ip, al);
38 mod = dwfl_addrmodule(ui->dwfl, ip);
40 mod = dwfl_report_elf(ui->dwfl, dso->short_name,
41 dso->long_name, -1, al->map->start,
44 return mod && dwfl_addrmodule(ui->dwfl, ip) == mod ? 0 : -1;
47 static int report_module(u64 ip, struct unwind_info *ui)
49 struct addr_location al;
51 return __report_module(&al, ip, ui);
54 static int entry(u64 ip, struct unwind_info *ui)
57 struct unwind_entry e;
58 struct addr_location al;
60 if (__report_module(&al, ip, ui))
67 pr_debug("unwind: %s:ip = 0x%" PRIx64 " (0x%" PRIx64 ")\n",
68 al.sym ? al.sym->name : "''",
70 al.map ? al.map->map_ip(al.map, ip) : (u64) 0);
72 return ui->cb(&e, ui->arg);
75 static pid_t next_thread(Dwfl *dwfl, void *arg, void **thread_argp)
77 /* We want only single thread to be processed. */
78 if (*thread_argp != NULL)
82 return dwfl_pid(dwfl);
85 static int access_dso_mem(struct unwind_info *ui, Dwarf_Addr addr,
88 struct addr_location al;
91 thread__find_addr_map(ui->thread, ui->machine, PERF_RECORD_MISC_USER,
92 MAP__FUNCTION, addr, &al);
94 pr_debug("unwind: no map for %lx\n", (unsigned long)addr);
101 size = dso__data_read_addr(al.map->dso, al.map, ui->machine,
102 addr, (u8 *) data, sizeof(*data));
104 return !(size == sizeof(*data));
107 static bool memory_read(Dwfl *dwfl __maybe_unused, Dwarf_Addr addr, Dwarf_Word *result,
110 struct unwind_info *ui = arg;
111 struct stack_dump *stack = &ui->sample->user_stack;
116 ret = perf_reg_value(&start, &ui->sample->user_regs, PERF_REG_SP);
120 end = start + stack->size;
122 /* Check overflow. */
123 if (addr + sizeof(Dwarf_Word) < addr)
126 if (addr < start || addr + sizeof(Dwarf_Word) > end) {
127 ret = access_dso_mem(ui, addr, result);
129 pr_debug("unwind: access_mem 0x%" PRIx64 " not inside range"
130 " 0x%" PRIx64 "-0x%" PRIx64 "\n",
137 offset = addr - start;
138 *result = *(Dwarf_Word *)&stack->data[offset];
139 pr_debug("unwind: access_mem addr 0x%" PRIx64 ", val %lx, offset %d\n",
140 addr, (unsigned long)*result, offset);
144 static const Dwfl_Thread_Callbacks callbacks = {
145 .next_thread = next_thread,
146 .memory_read = memory_read,
147 .set_initial_registers = libdw__arch_set_initial_registers,
151 frame_callback(Dwfl_Frame *state, void *arg)
153 struct unwind_info *ui = arg;
156 if (!dwfl_frame_pc(state, &pc, NULL)) {
157 pr_err("%s", dwfl_errmsg(-1));
158 return DWARF_CB_ABORT;
161 return entry(pc, ui) || !(--ui->max_stack) ?
162 DWARF_CB_ABORT : DWARF_CB_OK;
165 int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
166 struct machine *machine, struct thread *thread,
167 struct perf_sample *data,
170 struct unwind_info ui = {
176 .max_stack = max_stack,
181 if (!data->user_regs.regs)
184 ui.dwfl = dwfl_begin(&offline_callbacks);
188 err = perf_reg_value(&ip, &data->user_regs, PERF_REG_IP);
192 err = report_module(ip, &ui);
196 if (!dwfl_attach_state(ui.dwfl, EM_NONE, thread->tid, &callbacks, &ui))
199 err = dwfl_getthread_frames(ui.dwfl, thread->tid, frame_callback, &ui);
201 if (err && !ui.max_stack)
206 pr_debug("unwind: failed with '%s'\n", dwfl_errmsg(-1));