1// SPDX-License-Identifier: GPL-2.0
  2#include <linux/compiler.h>
  3#include <elfutils/libdw.h>
  4#include <elfutils/libdwfl.h>
  5#include <inttypes.h>
  6#include <errno.h>
  7#include "debug.h"
  8#include "dso.h"
  9#include "unwind.h"
 10#include "unwind-libdw.h"
 11#include "machine.h"
 12#include "map.h"
 13#include "symbol.h"
 14#include "thread.h"
 15#include <linux/types.h>
 16#include <linux/zalloc.h>
 17#include "event.h"
 18#include "perf_regs.h"
 19#include "callchain.h"
 20#include "util/env.h"
 21
 22static char *debuginfo_path;
 23
 24static int __find_debuginfo(Dwfl_Module *mod __maybe_unused, void **userdata,
 25			    const char *modname __maybe_unused, Dwarf_Addr base __maybe_unused,
 26			    const char *file_name, const char *debuglink_file __maybe_unused,
 27			    GElf_Word debuglink_crc __maybe_unused, char **debuginfo_file_name)
 28{
 29	const struct dso *dso = *userdata;
 30
 31	assert(dso);
 32	if (dso->symsrc_filename && strcmp (file_name, dso->symsrc_filename))
 33		*debuginfo_file_name = strdup(dso->symsrc_filename);
 34	return -1;
 35}
 36
 37static const Dwfl_Callbacks offline_callbacks = {
 38	.find_debuginfo		= __find_debuginfo,
 39	.debuginfo_path		= &debuginfo_path,
 40	.section_address	= dwfl_offline_section_address,
 41	// .find_elf is not set as we use dwfl_report_elf() instead.
 42};
 43
 44static int __report_module(struct addr_location *al, u64 ip,
 45			    struct unwind_info *ui)
 46{
 47	Dwfl_Module *mod;
 48	struct dso *dso = NULL;
 49	Dwarf_Addr base;
 50	/*
 51	 * Some callers will use al->sym, so we can't just use the
 52	 * cheaper thread__find_map() here.
 53	 */
 54	thread__find_symbol(ui->thread, PERF_RECORD_MISC_USER, ip, al);
 55
 56	if (al->map)
 57		dso = map__dso(al->map);
 58
 59	if (!dso)
 60		return 0;
 61
 62	/*
 63	 * The generated JIT DSO files only map the code segment without
 64	 * ELF headers.  Since JIT codes used to be packed in a memory
 65	 * segment, calculating the base address using pgoff falls into
 66	 * a different code in another DSO.  So just use the map->start
 67	 * directly to pick the correct one.
 68	 */
 69	if (!strncmp(dso->long_name, "/tmp/jitted-", 12))
 70		base = map__start(al->map);
 71	else
 72		base = map__start(al->map) - map__pgoff(al->map);
 73
 74	mod = dwfl_addrmodule(ui->dwfl, ip);
 75	if (mod) {
 76		Dwarf_Addr s;
 77
 78		dwfl_module_info(mod, NULL, &s, NULL, NULL, NULL, NULL, NULL);
 79		if (s != base)
 80			mod = NULL;
 81	}
 82
 83	if (!mod) {
 84		char filename[PATH_MAX];
 85
 86		__symbol__join_symfs(filename, sizeof(filename), dso->long_name);
 87		mod = dwfl_report_elf(ui->dwfl, dso->short_name, filename, -1,
 88				      base, false);
 89	}
 90	if (!mod) {
 91		char filename[PATH_MAX];
 92
 93		if (dso__build_id_filename(dso, filename, sizeof(filename), false))
 94			mod = dwfl_report_elf(ui->dwfl, dso->short_name, filename, -1,
 95					      base, false);
 96	}
 97
 98	if (mod) {
 99		void **userdatap;
100
101		dwfl_module_info(mod, &userdatap, NULL, NULL, NULL, NULL, NULL, NULL);
102		*userdatap = dso;
103	}
104
105	return mod && dwfl_addrmodule(ui->dwfl, ip) == mod ? 0 : -1;
106}
107
108static int report_module(u64 ip, struct unwind_info *ui)
109{
110	struct addr_location al;
111	int res;
112
113	addr_location__init(&al);
114	res = __report_module(&al, ip, ui);
115	addr_location__exit(&al);
116	return res;
117}
118
119/*
120 * Store all entries within entries array,
121 * we will process it after we finish unwind.
122 */
123static int entry(u64 ip, struct unwind_info *ui)
124
125{
126	struct unwind_entry *e = &ui->entries[ui->idx++];
127	struct addr_location al;
128
129	addr_location__init(&al);
130	if (__report_module(&al, ip, ui)) {
131		addr_location__exit(&al);
132		return -1;
133	}
134
135	e->ip	  = ip;
136	e->ms.maps = al.maps;
137	e->ms.map = al.map;
138	e->ms.sym = al.sym;
139
140	pr_debug("unwind: %s:ip = 0x%" PRIx64 " (0x%" PRIx64 ")\n",
141		 al.sym ? al.sym->name : "''",
142		 ip,
143		 al.map ? map__map_ip(al.map, ip) : (u64) 0);
144	addr_location__exit(&al);
145	return 0;
146}
147
148static pid_t next_thread(Dwfl *dwfl, void *arg, void **thread_argp)
149{
150	/* We want only single thread to be processed. */
151	if (*thread_argp != NULL)
152		return 0;
153
154	*thread_argp = arg;
155	return dwfl_pid(dwfl);
156}
157
158static int access_dso_mem(struct unwind_info *ui, Dwarf_Addr addr,
159			  Dwarf_Word *data)
160{
161	struct addr_location al;
162	ssize_t size;
163	struct dso *dso;
164
165	addr_location__init(&al);
166	if (!thread__find_map(ui->thread, PERF_RECORD_MISC_USER, addr, &al)) {
167		pr_debug("unwind: no map for %lx\n", (unsigned long)addr);
168		goto out_fail;
169	}
170	dso = map__dso(al.map);
171	if (!dso)
172		goto out_fail;
173
174	size = dso__data_read_addr(dso, al.map, ui->machine, addr, (u8 *) data, sizeof(*data));
 
 
 
 
175
176	addr_location__exit(&al);
177	return !(size == sizeof(*data));
178out_fail:
179	addr_location__exit(&al);
180	return -1;
181}
182
183static bool memory_read(Dwfl *dwfl __maybe_unused, Dwarf_Addr addr, Dwarf_Word *result,
184			void *arg)
185{
186	struct unwind_info *ui = arg;
187	const char *arch = perf_env__arch(ui->machine->env);
188	struct stack_dump *stack = &ui->sample->user_stack;
189	u64 start, end;
190	int offset;
191	int ret;
192
193	ret = perf_reg_value(&start, &ui->sample->user_regs,
194			     perf_arch_reg_sp(arch));
195	if (ret)
196		return false;
197
198	end = start + stack->size;
199
200	/* Check overflow. */
201	if (addr + sizeof(Dwarf_Word) < addr)
202		return false;
203
204	if (addr < start || addr + sizeof(Dwarf_Word) > end) {
205		ret = access_dso_mem(ui, addr, result);
206		if (ret) {
207			pr_debug("unwind: access_mem 0x%" PRIx64 " not inside range"
208				 " 0x%" PRIx64 "-0x%" PRIx64 "\n",
209				addr, start, end);
210			return false;
211		}
212		return true;
213	}
214
215	offset  = addr - start;
216	*result = *(Dwarf_Word *)&stack->data[offset];
217	pr_debug("unwind: access_mem addr 0x%" PRIx64 ", val %lx, offset %d\n",
218		 addr, (unsigned long)*result, offset);
219	return true;
220}
221
222static const Dwfl_Thread_Callbacks callbacks = {
223	.next_thread		= next_thread,
224	.memory_read		= memory_read,
225	.set_initial_registers	= libdw__arch_set_initial_registers,
226};
227
228static int
229frame_callback(Dwfl_Frame *state, void *arg)
230{
231	struct unwind_info *ui = arg;
232	Dwarf_Addr pc;
233	bool isactivation;
234
235	if (!dwfl_frame_pc(state, &pc, NULL)) {
236		if (!ui->best_effort)
237			pr_err("%s", dwfl_errmsg(-1));
238		return DWARF_CB_ABORT;
239	}
240
241	// report the module before we query for isactivation
242	report_module(pc, ui);
243
244	if (!dwfl_frame_pc(state, &pc, &isactivation)) {
245		if (!ui->best_effort)
246			pr_err("%s", dwfl_errmsg(-1));
247		return DWARF_CB_ABORT;
248	}
249
250	if (!isactivation)
251		--pc;
252
253	return entry(pc, ui) || !(--ui->max_stack) ?
254	       DWARF_CB_ABORT : DWARF_CB_OK;
255}
256
257int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
258			struct thread *thread,
259			struct perf_sample *data,
260			int max_stack,
261			bool best_effort)
262{
263	struct unwind_info *ui, ui_buf = {
264		.sample		= data,
265		.thread		= thread,
266		.machine	= RC_CHK_ACCESS(thread__maps(thread))->machine,
267		.cb		= cb,
268		.arg		= arg,
269		.max_stack	= max_stack,
270		.best_effort    = best_effort
271	};
272	const char *arch = perf_env__arch(ui_buf.machine->env);
273	Dwarf_Word ip;
274	int err = -EINVAL, i;
275
276	if (!data->user_regs.regs)
277		return -EINVAL;
278
279	ui = zalloc(sizeof(ui_buf) + sizeof(ui_buf.entries[0]) * max_stack);
280	if (!ui)
281		return -ENOMEM;
282
283	*ui = ui_buf;
284
285	ui->dwfl = dwfl_begin(&offline_callbacks);
286	if (!ui->dwfl)
287		goto out;
288
289	err = perf_reg_value(&ip, &data->user_regs, perf_arch_reg_ip(arch));
290	if (err)
291		goto out;
292
293	err = report_module(ip, ui);
294	if (err)
295		goto out;
296
297	err = !dwfl_attach_state(ui->dwfl, EM_NONE, thread__tid(thread), &callbacks, ui);
298	if (err)
299		goto out;
300
301	err = dwfl_getthread_frames(ui->dwfl, thread__tid(thread), frame_callback, ui);
302
303	if (err && ui->max_stack != max_stack)
304		err = 0;
305
306	/*
307	 * Display what we got based on the order setup.
308	 */
309	for (i = 0; i < ui->idx && !err; i++) {
310		int j = i;
311
312		if (callchain_param.order == ORDER_CALLER)
313			j = ui->idx - i - 1;
314
315		err = ui->entries[j].ip ? ui->cb(&ui->entries[j], ui->arg) : 0;
316	}
317
318 out:
319	if (err)
320		pr_debug("unwind: failed with '%s'\n", dwfl_errmsg(-1));
321
322	dwfl_end(ui->dwfl);
323	free(ui);
324	return 0;
325}

  1// SPDX-License-Identifier: GPL-2.0
  2#include <linux/compiler.h>
  3#include <elfutils/libdw.h>
  4#include <elfutils/libdwfl.h>
  5#include <inttypes.h>
  6#include <errno.h>
  7#include "debug.h"
  8#include "dso.h"
  9#include "unwind.h"
 10#include "unwind-libdw.h"
 11#include "machine.h"
 12#include "map.h"
 13#include "symbol.h"
 14#include "thread.h"
 15#include <linux/types.h>
 16#include <linux/zalloc.h>
 17#include "event.h"
 18#include "perf_regs.h"
 19#include "callchain.h"
 
 20
 21static char *debuginfo_path;
 22
 23static int __find_debuginfo(Dwfl_Module *mod __maybe_unused, void **userdata,
 24			    const char *modname __maybe_unused, Dwarf_Addr base __maybe_unused,
 25			    const char *file_name, const char *debuglink_file __maybe_unused,
 26			    GElf_Word debuglink_crc __maybe_unused, char **debuginfo_file_name)
 27{
 28	const struct dso *dso = *userdata;
 29
 30	assert(dso);
 31	if (dso->symsrc_filename && strcmp (file_name, dso->symsrc_filename))
 32		*debuginfo_file_name = strdup(dso->symsrc_filename);
 33	return -1;
 34}
 35
 36static const Dwfl_Callbacks offline_callbacks = {
 37	.find_debuginfo		= __find_debuginfo,
 38	.debuginfo_path		= &debuginfo_path,
 39	.section_address	= dwfl_offline_section_address,
 40	// .find_elf is not set as we use dwfl_report_elf() instead.
 41};
 42
 43static int __report_module(struct addr_location *al, u64 ip,
 44			    struct unwind_info *ui)
 45{
 46	Dwfl_Module *mod;
 47	struct dso *dso = NULL;
 
 48	/*
 49	 * Some callers will use al->sym, so we can't just use the
 50	 * cheaper thread__find_map() here.
 51	 */
 52	thread__find_symbol(ui->thread, PERF_RECORD_MISC_USER, ip, al);
 53
 54	if (al->map)
 55		dso = al->map->dso;
 56
 57	if (!dso)
 58		return 0;
 59
 
 
 
 
 
 
 
 
 
 
 
 
 60	mod = dwfl_addrmodule(ui->dwfl, ip);
 61	if (mod) {
 62		Dwarf_Addr s;
 63
 64		dwfl_module_info(mod, NULL, &s, NULL, NULL, NULL, NULL, NULL);
 65		if (s != al->map->start - al->map->pgoff)
 66			mod = 0;
 67	}
 68
 69	if (!mod)
 70		mod = dwfl_report_elf(ui->dwfl, dso->short_name, dso->long_name, -1,
 71				      al->map->start - al->map->pgoff, false);
 
 
 
 
 72	if (!mod) {
 73		char filename[PATH_MAX];
 74
 75		if (dso__build_id_filename(dso, filename, sizeof(filename), false))
 76			mod = dwfl_report_elf(ui->dwfl, dso->short_name, filename, -1,
 77					      al->map->start - al->map->pgoff, false);
 78	}
 79
 80	if (mod) {
 81		void **userdatap;
 82
 83		dwfl_module_info(mod, &userdatap, NULL, NULL, NULL, NULL, NULL, NULL);
 84		*userdatap = dso;
 85	}
 86
 87	return mod && dwfl_addrmodule(ui->dwfl, ip) == mod ? 0 : -1;
 88}
 89
 90static int report_module(u64 ip, struct unwind_info *ui)
 91{
 92	struct addr_location al;
 
 93
 94	return __report_module(&al, ip, ui);
 
 
 
 95}
 96
 97/*
 98 * Store all entries within entries array,
 99 * we will process it after we finish unwind.
100 */
101static int entry(u64 ip, struct unwind_info *ui)
102
103{
104	struct unwind_entry *e = &ui->entries[ui->idx++];
105	struct addr_location al;
106
107	if (__report_module(&al, ip, ui))
 
 
108		return -1;
 
109
110	e->ip	  = ip;
111	e->ms.maps = al.maps;
112	e->ms.map = al.map;
113	e->ms.sym = al.sym;
114
115	pr_debug("unwind: %s:ip = 0x%" PRIx64 " (0x%" PRIx64 ")\n",
116		 al.sym ? al.sym->name : "''",
117		 ip,
118		 al.map ? al.map->map_ip(al.map, ip) : (u64) 0);
 
119	return 0;
120}
121
122static pid_t next_thread(Dwfl *dwfl, void *arg, void **thread_argp)
123{
124	/* We want only single thread to be processed. */
125	if (*thread_argp != NULL)
126		return 0;
127
128	*thread_argp = arg;
129	return dwfl_pid(dwfl);
130}
131
132static int access_dso_mem(struct unwind_info *ui, Dwarf_Addr addr,
133			  Dwarf_Word *data)
134{
135	struct addr_location al;
136	ssize_t size;
 
137
 
138	if (!thread__find_map(ui->thread, PERF_RECORD_MISC_USER, addr, &al)) {
139		pr_debug("unwind: no map for %lx\n", (unsigned long)addr);
140		return -1;
141	}
 
 
 
142
143	if (!al.map->dso)
144		return -1;
145
146	size = dso__data_read_addr(al.map->dso, al.map, ui->machine,
147				   addr, (u8 *) data, sizeof(*data));
148
 
149	return !(size == sizeof(*data));
 
 
 
150}
151
152static bool memory_read(Dwfl *dwfl __maybe_unused, Dwarf_Addr addr, Dwarf_Word *result,
153			void *arg)
154{
155	struct unwind_info *ui = arg;
 
156	struct stack_dump *stack = &ui->sample->user_stack;
157	u64 start, end;
158	int offset;
159	int ret;
160
161	ret = perf_reg_value(&start, &ui->sample->user_regs, PERF_REG_SP);
 
162	if (ret)
163		return false;
164
165	end = start + stack->size;
166
167	/* Check overflow. */
168	if (addr + sizeof(Dwarf_Word) < addr)
169		return false;
170
171	if (addr < start || addr + sizeof(Dwarf_Word) > end) {
172		ret = access_dso_mem(ui, addr, result);
173		if (ret) {
174			pr_debug("unwind: access_mem 0x%" PRIx64 " not inside range"
175				 " 0x%" PRIx64 "-0x%" PRIx64 "\n",
176				addr, start, end);
177			return false;
178		}
179		return true;
180	}
181
182	offset  = addr - start;
183	*result = *(Dwarf_Word *)&stack->data[offset];
184	pr_debug("unwind: access_mem addr 0x%" PRIx64 ", val %lx, offset %d\n",
185		 addr, (unsigned long)*result, offset);
186	return true;
187}
188
189static const Dwfl_Thread_Callbacks callbacks = {
190	.next_thread		= next_thread,
191	.memory_read		= memory_read,
192	.set_initial_registers	= libdw__arch_set_initial_registers,
193};
194
195static int
196frame_callback(Dwfl_Frame *state, void *arg)
197{
198	struct unwind_info *ui = arg;
199	Dwarf_Addr pc;
200	bool isactivation;
201
202	if (!dwfl_frame_pc(state, &pc, NULL)) {
203		if (!ui->best_effort)
204			pr_err("%s", dwfl_errmsg(-1));
205		return DWARF_CB_ABORT;
206	}
207
208	// report the module before we query for isactivation
209	report_module(pc, ui);
210
211	if (!dwfl_frame_pc(state, &pc, &isactivation)) {
212		if (!ui->best_effort)
213			pr_err("%s", dwfl_errmsg(-1));
214		return DWARF_CB_ABORT;
215	}
216
217	if (!isactivation)
218		--pc;
219
220	return entry(pc, ui) || !(--ui->max_stack) ?
221	       DWARF_CB_ABORT : DWARF_CB_OK;
222}
223
224int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
225			struct thread *thread,
226			struct perf_sample *data,
227			int max_stack,
228			bool best_effort)
229{
230	struct unwind_info *ui, ui_buf = {
231		.sample		= data,
232		.thread		= thread,
233		.machine	= thread->maps->machine,
234		.cb		= cb,
235		.arg		= arg,
236		.max_stack	= max_stack,
237		.best_effort    = best_effort
238	};
 
239	Dwarf_Word ip;
240	int err = -EINVAL, i;
241
242	if (!data->user_regs.regs)
243		return -EINVAL;
244
245	ui = zalloc(sizeof(ui_buf) + sizeof(ui_buf.entries[0]) * max_stack);
246	if (!ui)
247		return -ENOMEM;
248
249	*ui = ui_buf;
250
251	ui->dwfl = dwfl_begin(&offline_callbacks);
252	if (!ui->dwfl)
253		goto out;
254
255	err = perf_reg_value(&ip, &data->user_regs, PERF_REG_IP);
256	if (err)
257		goto out;
258
259	err = report_module(ip, ui);
260	if (err)
261		goto out;
262
263	err = !dwfl_attach_state(ui->dwfl, EM_NONE, thread->tid, &callbacks, ui);
264	if (err)
265		goto out;
266
267	err = dwfl_getthread_frames(ui->dwfl, thread->tid, frame_callback, ui);
268
269	if (err && ui->max_stack != max_stack)
270		err = 0;
271
272	/*
273	 * Display what we got based on the order setup.
274	 */
275	for (i = 0; i < ui->idx && !err; i++) {
276		int j = i;
277
278		if (callchain_param.order == ORDER_CALLER)
279			j = ui->idx - i - 1;
280
281		err = ui->entries[j].ip ? ui->cb(&ui->entries[j], ui->arg) : 0;
282	}
283
284 out:
285	if (err)
286		pr_debug("unwind: failed with '%s'\n", dwfl_errmsg(-1));
287
288	dwfl_end(ui->dwfl);
289	free(ui);
290	return 0;
291}