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tracing: Provide trace events interface for uprobes

Implements trace_event support for uprobes. In its current form it can be used to put probes at a specified offset in a file and dump the required registers when the code flow reaches the probed address. The following example shows how to dump the instruction pointer and %ax a register at the probed text address. Here we are trying to probe zfree in /bin/zsh: # cd /sys/kernel/debug/tracing/ # cat /proc/`pgrep zsh`/maps | grep /bin/zsh | grep r-xp 00400000-0048a000 r-xp 00000000 08:03 130904 /bin/zsh # objdump -T /bin/zsh | grep -w zfree 0000000000446420 g DF .text 0000000000000012 Base zfree # echo 'p /bin/zsh:0x46420 %ip %ax' > uprobe_events # cat uprobe_events p:uprobes/p_zsh_0x46420 /bin/zsh:0x0000000000046420 # echo 1 > events/uprobes/enable # sleep 20 # echo 0 > events/uprobes/enable # cat trace # tracer: nop # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | zsh-24842 [006] 258544.995456: p_zsh_0x46420: (0x446420) arg1=446421 arg2=79 zsh-24842 [007] 258545.000270: p_zsh_0x46420: (0x446420) arg1=446421 arg2=79 zsh-24842 [002] 258545.043929: p_zsh_0x46420: (0x446420) arg1=446421 arg2=79 zsh-24842 [004] 258547.046129: p_zsh_0x46420: (0x446420) arg1=446421 arg2=79

Srikar Dronamraju committed 14 years ago

Commit f3f096c1 parent 8ab83f59 files · +919 −7Browse files

Showing the changes to kernel (7 of 9 files). Show all

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7 files
  1. kernel/trace/Kconfig +16 −0
  2. kernel/trace/Makefile +1 −0
  3. kernel/trace/trace.h +5 −0
  4. kernel/trace/trace_kprobe.c +1 −1
  5. kernel/trace/trace_probe.c +10 −4
  6. kernel/trace/trace_probe.h +2 −1
  7. kernel/trace/trace_uprobe.c +788 −0
kernel/trace/Kconfig+16−0
@@ -386,6 +386,22 @@ config KPROBE_EVENT · 385 unmodified lines
386 This option is also required by perf-probe subcommand of perf tools.386 This option is also required by perf-probe subcommand of perf tools.
387 If you want to use perf tools, this option is strongly recommended.387 If you want to use perf tools, this option is strongly recommended.
388 388
389config UPROBE_EVENT
390 bool "Enable uprobes-based dynamic events"
391 depends on ARCH_SUPPORTS_UPROBES
392 depends on MMU
393 select UPROBES
394 select PROBE_EVENTS
395 select TRACING
396 default n
397 help
398 This allows the user to add tracing events on top of userspace
399 dynamic events (similar to tracepoints) on the fly via the trace
400 events interface. Those events can be inserted wherever uprobes
401 can probe, and record various registers.
402 This option is required if you plan to use perf-probe subcommand
403 of perf tools on user space applications.
404
389config PROBE_EVENTS405config PROBE_EVENTS
390 def_bool n406 def_bool n
391 407
kernel/trace/Makefile+1−0
@@ -62,5 +62,6 @@ ifeq ($(CONFIG_TRACING),y) · 61 unmodified lines
62obj-$(CONFIG_KGDB_KDB) += trace_kdb.o62obj-$(CONFIG_KGDB_KDB) += trace_kdb.o
63endif63endif
64obj-$(CONFIG_PROBE_EVENTS) += trace_probe.o64obj-$(CONFIG_PROBE_EVENTS) += trace_probe.o
65obj-$(CONFIG_UPROBE_EVENT) += trace_uprobe.o
65 66
66libftrace-y := ftrace.o67libftrace-y := ftrace.o
kernel/trace/trace.h+5−0
@@ -103,6 +103,11 @@ struct kretprobe_trace_entry_head { · 102 unmodified lines
103 unsigned long ret_ip;103 unsigned long ret_ip;
104};104};
105 105
106struct uprobe_trace_entry_head {
107 struct trace_entry ent;
108 unsigned long ip;
109};
110
106/*111/*
107 * trace_flag_type is an enumeration that holds different112 * trace_flag_type is an enumeration that holds different
108 * states when a trace occurs. These are:113 * states when a trace occurs. These are:
kernel/trace/trace_kprobe.c+1−1
@@ -525,7 +525,7 @@ static int create_trace_probe(int argc, char **argv) · 524 unmodified lines
525 525
526 /* Parse fetch argument */526 /* Parse fetch argument */
527 ret = traceprobe_parse_probe_arg(arg, &tp->size, &tp->args[i],527 ret = traceprobe_parse_probe_arg(arg, &tp->size, &tp->args[i],
528 is_return);528 is_return, true);
529 if (ret) {529 if (ret) {
530 pr_info("Parse error at argument[%d]. (%d)\n", i, ret);530 pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
531 goto error;531 goto error;
kernel/trace/trace_probe.c+10−4
@@ -550,7 +550,7 @@ static int parse_probe_vars(char *arg, const struct fetch_type *t, · 549 unmodified lines
550 550
551/* Recursive argument parser */551/* Recursive argument parser */
552static int parse_probe_arg(char *arg, const struct fetch_type *t,552static int parse_probe_arg(char *arg, const struct fetch_type *t,
553 struct fetch_param *f, bool is_return)553 struct fetch_param *f, bool is_return, bool is_kprobe)
554{554{
555 unsigned long param;555 unsigned long param;
556 long offset;556 long offset;
@@ -558,6 +558,11 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t, · 1 unmodified line
558 int ret;558 int ret;
559 559
560 ret = 0;560 ret = 0;
561
562 /* Until uprobe_events supports only reg arguments */
563 if (!is_kprobe && arg[0] != '%')
564 return -EINVAL;
565
561 switch (arg[0]) {566 switch (arg[0]) {
562 case '$':567 case '$':
563 ret = parse_probe_vars(arg + 1, t, f, is_return);568 ret = parse_probe_vars(arg + 1, t, f, is_return);
@@ -619,7 +624,8 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t, · 55 unmodified lines
619 return -ENOMEM;624 return -ENOMEM;
620 625
621 dprm->offset = offset;626 dprm->offset = offset;
622 ret = parse_probe_arg(arg, t2, &dprm->orig, is_return);627 ret = parse_probe_arg(arg, t2, &dprm->orig, is_return,
628 is_kprobe);
623 if (ret)629 if (ret)
624 kfree(dprm);630 kfree(dprm);
625 else {631 else {
@@ -677,7 +683,7 @@ static int __parse_bitfield_probe_arg(const char *bf, · 51 unmodified lines
677 683
678/* String length checking wrapper */684/* String length checking wrapper */
679int traceprobe_parse_probe_arg(char *arg, ssize_t *size,685int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
680 struct probe_arg *parg, bool is_return)686 struct probe_arg *parg, bool is_return, bool is_kprobe)
681{687{
682 const char *t;688 const char *t;
683 int ret;689 int ret;
@@ -703,7 +709,7 @@ int traceprobe_parse_probe_arg(char *arg, ssize_t *size, · 19 unmodified lines
703 }709 }
704 parg->offset = *size;710 parg->offset = *size;
705 *size += parg->type->size;711 *size += parg->type->size;
706 ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return);712 ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return, is_kprobe);
707 713
708 if (ret >= 0 && t != NULL)714 if (ret >= 0 && t != NULL)
709 ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);715 ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
kernel/trace/trace_probe.h+2−1
@@ -66,6 +66,7 @@ · 65 unmodified lines
66#define TP_FLAG_TRACE 166#define TP_FLAG_TRACE 1
67#define TP_FLAG_PROFILE 267#define TP_FLAG_PROFILE 2
68#define TP_FLAG_REGISTERED 468#define TP_FLAG_REGISTERED 4
69#define TP_FLAG_UPROBE 8
69 70
70 71
71/* data_rloc: data relative location, compatible with u32 */72/* data_rloc: data relative location, compatible with u32 */
@@ -143,7 +144,7 @@ static inline int is_good_name(const char *name) · 71 unmodified lines
143}144}
144 145
145extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size,146extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
146 struct probe_arg *parg, bool is_return);147 struct probe_arg *parg, bool is_return, bool is_kprobe);
147 148
148extern int traceprobe_conflict_field_name(const char *name,149extern int traceprobe_conflict_field_name(const char *name,
149 struct probe_arg *args, int narg);150 struct probe_arg *args, int narg);
kernel/trace/trace_uprobe.c+788−0
@@ -0,0 +1,788 @@
1/*
2 * uprobes-based tracing events
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
16 *
17 * Copyright (C) IBM Corporation, 2010-2012
18 * Author: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
19 */
20
21#include <linux/module.h>
22#include <linux/uaccess.h>
23#include <linux/uprobes.h>
24#include <linux/namei.h>
25
26#include "trace_probe.h"
27
28#define UPROBE_EVENT_SYSTEM "uprobes"
29
30/*
31 * uprobe event core functions
32 */
33struct trace_uprobe;
34struct uprobe_trace_consumer {
35 struct uprobe_consumer cons;
36 struct trace_uprobe *tu;
37};
38
39struct trace_uprobe {
40 struct list_head list;
41 struct ftrace_event_class class;
42 struct ftrace_event_call call;
43 struct uprobe_trace_consumer *consumer;
44 struct inode *inode;
45 char *filename;
46 unsigned long offset;
47 unsigned long nhit;
48 unsigned int flags; /* For TP_FLAG_* */
49 ssize_t size; /* trace entry size */
50 unsigned int nr_args;
51 struct probe_arg args[];
52};
53
54#define SIZEOF_TRACE_UPROBE(n) \
55 (offsetof(struct trace_uprobe, args) + \
56 (sizeof(struct probe_arg) * (n)))
57
58static int register_uprobe_event(struct trace_uprobe *tu);
59static void unregister_uprobe_event(struct trace_uprobe *tu);
60
61static DEFINE_MUTEX(uprobe_lock);
62static LIST_HEAD(uprobe_list);
63
64static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
65
66/*
67 * Allocate new trace_uprobe and initialize it (including uprobes).
68 */
69static struct trace_uprobe *
70alloc_trace_uprobe(const char *group, const char *event, int nargs)
71{
72 struct trace_uprobe *tu;
73
74 if (!event || !is_good_name(event))
75 return ERR_PTR(-EINVAL);
76
77 if (!group || !is_good_name(group))
78 return ERR_PTR(-EINVAL);
79
80 tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL);
81 if (!tu)
82 return ERR_PTR(-ENOMEM);
83
84 tu->call.class = &tu->class;
85 tu->call.name = kstrdup(event, GFP_KERNEL);
86 if (!tu->call.name)
87 goto error;
88
89 tu->class.system = kstrdup(group, GFP_KERNEL);
90 if (!tu->class.system)
91 goto error;
92
93 INIT_LIST_HEAD(&tu->list);
94 return tu;
95
96error:
97 kfree(tu->call.name);
98 kfree(tu);
99
100 return ERR_PTR(-ENOMEM);
101}
102
103static void free_trace_uprobe(struct trace_uprobe *tu)
104{
105 int i;
106
107 for (i = 0; i < tu->nr_args; i++)
108 traceprobe_free_probe_arg(&tu->args[i]);
109
110 iput(tu->inode);
111 kfree(tu->call.class->system);
112 kfree(tu->call.name);
113 kfree(tu->filename);
114 kfree(tu);
115}
116
117static struct trace_uprobe *find_probe_event(const char *event, const char *group)
118{
119 struct trace_uprobe *tu;
120
121 list_for_each_entry(tu, &uprobe_list, list)
122 if (strcmp(tu->call.name, event) == 0 &&
123 strcmp(tu->call.class->system, group) == 0)
124 return tu;
125
126 return NULL;
127}
128
129/* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */
130static void unregister_trace_uprobe(struct trace_uprobe *tu)
131{
132 list_del(&tu->list);
133 unregister_uprobe_event(tu);
134 free_trace_uprobe(tu);
135}
136
137/* Register a trace_uprobe and probe_event */
138static int register_trace_uprobe(struct trace_uprobe *tu)
139{
140 struct trace_uprobe *old_tp;
141 int ret;
142
143 mutex_lock(&uprobe_lock);
144
145 /* register as an event */
146 old_tp = find_probe_event(tu->call.name, tu->call.class->system);
147 if (old_tp)
148 /* delete old event */
149 unregister_trace_uprobe(old_tp);
150
151 ret = register_uprobe_event(tu);
152 if (ret) {
153 pr_warning("Failed to register probe event(%d)\n", ret);
154 goto end;
155 }
156
157 list_add_tail(&tu->list, &uprobe_list);
158
159end:
160 mutex_unlock(&uprobe_lock);
161
162 return ret;
163}
164
165/*
166 * Argument syntax:
167 * - Add uprobe: p[:[GRP/]EVENT] PATH:SYMBOL[+offs] [FETCHARGS]
168 *
169 * - Remove uprobe: -:[GRP/]EVENT
170 */
171static int create_trace_uprobe(int argc, char **argv)
172{
173 struct trace_uprobe *tu;
174 struct inode *inode;
175 char *arg, *event, *group, *filename;
176 char buf[MAX_EVENT_NAME_LEN];
177 struct path path;
178 unsigned long offset;
179 bool is_delete;
180 int i, ret;
181
182 inode = NULL;
183 ret = 0;
184 is_delete = false;
185 event = NULL;
186 group = NULL;
187
188 /* argc must be >= 1 */
189 if (argv[0][0] == '-')
190 is_delete = true;
191 else if (argv[0][0] != 'p') {
192 pr_info("Probe definition must be started with 'p', 'r' or" " '-'.\n");
193 return -EINVAL;
194 }
195
196 if (argv[0][1] == ':') {
197 event = &argv[0][2];
198 arg = strchr(event, '/');
199
200 if (arg) {
201 group = event;
202 event = arg + 1;
203 event[-1] = '\0';
204
205 if (strlen(group) == 0) {
206 pr_info("Group name is not specified\n");
207 return -EINVAL;
208 }
209 }
210 if (strlen(event) == 0) {
211 pr_info("Event name is not specified\n");
212 return -EINVAL;
213 }
214 }
215 if (!group)
216 group = UPROBE_EVENT_SYSTEM;
217
218 if (is_delete) {
219 if (!event) {
220 pr_info("Delete command needs an event name.\n");
221 return -EINVAL;
222 }
223 mutex_lock(&uprobe_lock);
224 tu = find_probe_event(event, group);
225
226 if (!tu) {
227 mutex_unlock(&uprobe_lock);
228 pr_info("Event %s/%s doesn't exist.\n", group, event);
229 return -ENOENT;
230 }
231 /* delete an event */
232 unregister_trace_uprobe(tu);
233 mutex_unlock(&uprobe_lock);
234 return 0;
235 }
236
237 if (argc < 2) {
238 pr_info("Probe point is not specified.\n");
239 return -EINVAL;
240 }
241 if (isdigit(argv[1][0])) {
242 pr_info("probe point must be have a filename.\n");
243 return -EINVAL;
244 }
245 arg = strchr(argv[1], ':');
246 if (!arg)
247 goto fail_address_parse;
248
249 *arg++ = '\0';
250 filename = argv[1];
251 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
252 if (ret)
253 goto fail_address_parse;
254
255 ret = strict_strtoul(arg, 0, &offset);
256 if (ret)
257 goto fail_address_parse;
258
259 inode = igrab(path.dentry->d_inode);
260
261 argc -= 2;
262 argv += 2;
263
264 /* setup a probe */
265 if (!event) {
266 char *tail = strrchr(filename, '/');
267 char *ptr;
268
269 ptr = kstrdup((tail ? tail + 1 : filename), GFP_KERNEL);
270 if (!ptr) {
271 ret = -ENOMEM;
272 goto fail_address_parse;
273 }
274
275 tail = ptr;
276 ptr = strpbrk(tail, ".-_");
277 if (ptr)
278 *ptr = '\0';
279
280 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
281 event = buf;
282 kfree(tail);
283 }
284
285 tu = alloc_trace_uprobe(group, event, argc);
286 if (IS_ERR(tu)) {
287 pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu));
288 ret = PTR_ERR(tu);
289 goto fail_address_parse;
290 }
291 tu->offset = offset;
292 tu->inode = inode;
293 tu->filename = kstrdup(filename, GFP_KERNEL);
294
295 if (!tu->filename) {
296 pr_info("Failed to allocate filename.\n");
297 ret = -ENOMEM;
298 goto error;
299 }
300
301 /* parse arguments */
302 ret = 0;
303 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
304 /* Increment count for freeing args in error case */
305 tu->nr_args++;
306
307 /* Parse argument name */
308 arg = strchr(argv[i], '=');
309 if (arg) {
310 *arg++ = '\0';
311 tu->args[i].name = kstrdup(argv[i], GFP_KERNEL);
312 } else {
313 arg = argv[i];
314 /* If argument name is omitted, set "argN" */
315 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
316 tu->args[i].name = kstrdup(buf, GFP_KERNEL);
317 }
318
319 if (!tu->args[i].name) {
320 pr_info("Failed to allocate argument[%d] name.\n", i);
321 ret = -ENOMEM;
322 goto error;
323 }
324
325 if (!is_good_name(tu->args[i].name)) {
326 pr_info("Invalid argument[%d] name: %s\n", i, tu->args[i].name);
327 ret = -EINVAL;
328 goto error;
329 }
330
331 if (traceprobe_conflict_field_name(tu->args[i].name, tu->args, i)) {
332 pr_info("Argument[%d] name '%s' conflicts with "
333 "another field.\n", i, argv[i]);
334 ret = -EINVAL;
335 goto error;
336 }
337
338 /* Parse fetch argument */
339 ret = traceprobe_parse_probe_arg(arg, &tu->size, &tu->args[i], false, false);
340 if (ret) {
341 pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
342 goto error;
343 }
344 }
345
346 ret = register_trace_uprobe(tu);
347 if (ret)
348 goto error;
349 return 0;
350
351error:
352 free_trace_uprobe(tu);
353 return ret;
354
355fail_address_parse:
356 if (inode)
357 iput(inode);
358
359 pr_info("Failed to parse address.\n");
360
361 return ret;
362}
363
364static void cleanup_all_probes(void)
365{
366 struct trace_uprobe *tu;
367
368 mutex_lock(&uprobe_lock);
369 while (!list_empty(&uprobe_list)) {
370 tu = list_entry(uprobe_list.next, struct trace_uprobe, list);
371 unregister_trace_uprobe(tu);
372 }
373 mutex_unlock(&uprobe_lock);
374}
375
376/* Probes listing interfaces */
377static void *probes_seq_start(struct seq_file *m, loff_t *pos)
378{
379 mutex_lock(&uprobe_lock);
380 return seq_list_start(&uprobe_list, *pos);
381}
382
383static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
384{
385 return seq_list_next(v, &uprobe_list, pos);
386}
387
388static void probes_seq_stop(struct seq_file *m, void *v)
389{
390 mutex_unlock(&uprobe_lock);
391}
392
393static int probes_seq_show(struct seq_file *m, void *v)
394{
395 struct trace_uprobe *tu = v;
396 int i;
397
398 seq_printf(m, "p:%s/%s", tu->call.class->system, tu->call.name);
399 seq_printf(m, " %s:0x%p", tu->filename, (void *)tu->offset);
400
401 for (i = 0; i < tu->nr_args; i++)
402 seq_printf(m, " %s=%s", tu->args[i].name, tu->args[i].comm);
403
404 seq_printf(m, "\n");
405 return 0;
406}
407
408static const struct seq_operations probes_seq_op = {
409 .start = probes_seq_start,
410 .next = probes_seq_next,
411 .stop = probes_seq_stop,
412 .show = probes_seq_show
413};
414
415static int probes_open(struct inode *inode, struct file *file)
416{
417 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC))
418 cleanup_all_probes();
419
420 return seq_open(file, &probes_seq_op);
421}
422
423static ssize_t probes_write(struct file *file, const char __user *buffer,
424 size_t count, loff_t *ppos)
425{
426 return traceprobe_probes_write(file, buffer, count, ppos, create_trace_uprobe);
427}
428
429static const struct file_operations uprobe_events_ops = {
430 .owner = THIS_MODULE,
431 .open = probes_open,
432 .read = seq_read,
433 .llseek = seq_lseek,
434 .release = seq_release,
435 .write = probes_write,
436};
437
438/* Probes profiling interfaces */
439static int probes_profile_seq_show(struct seq_file *m, void *v)
440{
441 struct trace_uprobe *tu = v;
442
443 seq_printf(m, " %s %-44s %15lu\n", tu->filename, tu->call.name, tu->nhit);
444 return 0;
445}
446
447static const struct seq_operations profile_seq_op = {
448 .start = probes_seq_start,
449 .next = probes_seq_next,
450 .stop = probes_seq_stop,
451 .show = probes_profile_seq_show
452};
453
454static int profile_open(struct inode *inode, struct file *file)
455{
456 return seq_open(file, &profile_seq_op);
457}
458
459static const struct file_operations uprobe_profile_ops = {
460 .owner = THIS_MODULE,
461 .open = profile_open,
462 .read = seq_read,
463 .llseek = seq_lseek,
464 .release = seq_release,
465};
466
467/* uprobe handler */
468static void uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs)
469{
470 struct uprobe_trace_entry_head *entry;
471 struct ring_buffer_event *event;
472 struct ring_buffer *buffer;
473 u8 *data;
474 int size, i, pc;
475 unsigned long irq_flags;
476 struct ftrace_event_call *call = &tu->call;
477
478 tu->nhit++;
479
480 local_save_flags(irq_flags);
481 pc = preempt_count();
482
483 size = sizeof(*entry) + tu->size;
484
485 event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
486 size, irq_flags, pc);
487 if (!event)
488 return;
489
490 entry = ring_buffer_event_data(event);
491 entry->ip = uprobe_get_swbp_addr(task_pt_regs(current));
492 data = (u8 *)&entry[1];
493 for (i = 0; i < tu->nr_args; i++)
494 call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
495
496 if (!filter_current_check_discard(buffer, call, entry, event))
497 trace_buffer_unlock_commit(buffer, event, irq_flags, pc);
498}
499
500/* Event entry printers */
501static enum print_line_t
502print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
503{
504 struct uprobe_trace_entry_head *field;
505 struct trace_seq *s = &iter->seq;
506 struct trace_uprobe *tu;
507 u8 *data;
508 int i;
509
510 field = (struct uprobe_trace_entry_head *)iter->ent;
511 tu = container_of(event, struct trace_uprobe, call.event);
512
513 if (!trace_seq_printf(s, "%s: (", tu->call.name))
514 goto partial;
515
516 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
517 goto partial;
518
519 if (!trace_seq_puts(s, ")"))
520 goto partial;
521
522 data = (u8 *)&field[1];
523 for (i = 0; i < tu->nr_args; i++) {
524 if (!tu->args[i].type->print(s, tu->args[i].name,
525 data + tu->args[i].offset, field))
526 goto partial;
527 }
528
529 if (trace_seq_puts(s, "\n"))
530 return TRACE_TYPE_HANDLED;
531
532partial:
533 return TRACE_TYPE_PARTIAL_LINE;
534}
535
536static int probe_event_enable(struct trace_uprobe *tu, int flag)
537{
538 struct uprobe_trace_consumer *utc;
539 int ret = 0;
540
541 if (!tu->inode || tu->consumer)
542 return -EINTR;
543
544 utc = kzalloc(sizeof(struct uprobe_trace_consumer), GFP_KERNEL);
545 if (!utc)
546 return -EINTR;
547
548 utc->cons.handler = uprobe_dispatcher;
549 utc->cons.filter = NULL;
550 ret = uprobe_register(tu->inode, tu->offset, &utc->cons);
551 if (ret) {
552 kfree(utc);
553 return ret;
554 }
555
556 tu->flags |= flag;
557 utc->tu = tu;
558 tu->consumer = utc;
559
560 return 0;
561}
562
563static void probe_event_disable(struct trace_uprobe *tu, int flag)
564{
565 if (!tu->inode || !tu->consumer)
566 return;
567
568 uprobe_unregister(tu->inode, tu->offset, &tu->consumer->cons);
569 tu->flags &= ~flag;
570 kfree(tu->consumer);
571 tu->consumer = NULL;
572}
573
574static int uprobe_event_define_fields(struct ftrace_event_call *event_call)
575{
576 int ret, i;
577 struct uprobe_trace_entry_head field;
578 struct trace_uprobe *tu = (struct trace_uprobe *)event_call->data;
579
580 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
581 /* Set argument names as fields */
582 for (i = 0; i < tu->nr_args; i++) {
583 ret = trace_define_field(event_call, tu->args[i].type->fmttype,
584 tu->args[i].name,
585 sizeof(field) + tu->args[i].offset,
586 tu->args[i].type->size,
587 tu->args[i].type->is_signed,
588 FILTER_OTHER);
589
590 if (ret)
591 return ret;
592 }
593 return 0;
594}
595
596#define LEN_OR_ZERO (len ? len - pos : 0)
597static int __set_print_fmt(struct trace_uprobe *tu, char *buf, int len)
598{
599 const char *fmt, *arg;
600 int i;
601 int pos = 0;
602
603 fmt = "(%lx)";
604 arg = "REC->" FIELD_STRING_IP;
605
606 /* When len=0, we just calculate the needed length */
607
608 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
609
610 for (i = 0; i < tu->nr_args; i++) {
611 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
612 tu->args[i].name, tu->args[i].type->fmt);
613 }
614
615 pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
616
617 for (i = 0; i < tu->nr_args; i++) {
618 pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
619 tu->args[i].name);
620 }
621
622 return pos; /* return the length of print_fmt */
623}
624#undef LEN_OR_ZERO
625
626static int set_print_fmt(struct trace_uprobe *tu)
627{
628 char *print_fmt;
629 int len;
630
631 /* First: called with 0 length to calculate the needed length */
632 len = __set_print_fmt(tu, NULL, 0);
633 print_fmt = kmalloc(len + 1, GFP_KERNEL);
634 if (!print_fmt)
635 return -ENOMEM;
636
637 /* Second: actually write the @print_fmt */
638 __set_print_fmt(tu, print_fmt, len + 1);
639 tu->call.print_fmt = print_fmt;
640
641 return 0;
642}
643
644#ifdef CONFIG_PERF_EVENTS
645/* uprobe profile handler */
646static void uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs)
647{
648 struct ftrace_event_call *call = &tu->call;
649 struct uprobe_trace_entry_head *entry;
650 struct hlist_head *head;
651 u8 *data;
652 int size, __size, i;
653 int rctx;
654
655 __size = sizeof(*entry) + tu->size;
656 size = ALIGN(__size + sizeof(u32), sizeof(u64));
657 size -= sizeof(u32);
658 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
659 return;
660
661 preempt_disable();
662
663 entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
664 if (!entry)
665 goto out;
666
667 entry->ip = uprobe_get_swbp_addr(task_pt_regs(current));
668 data = (u8 *)&entry[1];
669 for (i = 0; i < tu->nr_args; i++)
670 call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
671
672 head = this_cpu_ptr(call->perf_events);
673 perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head);
674
675 out:
676 preempt_enable();
677}
678#endif /* CONFIG_PERF_EVENTS */
679
680static
681int trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type, void *data)
682{
683 struct trace_uprobe *tu = (struct trace_uprobe *)event->data;
684
685 switch (type) {
686 case TRACE_REG_REGISTER:
687 return probe_event_enable(tu, TP_FLAG_TRACE);
688
689 case TRACE_REG_UNREGISTER:
690 probe_event_disable(tu, TP_FLAG_TRACE);
691 return 0;
692
693#ifdef CONFIG_PERF_EVENTS
694 case TRACE_REG_PERF_REGISTER:
695 return probe_event_enable(tu, TP_FLAG_PROFILE);
696
697 case TRACE_REG_PERF_UNREGISTER:
698 probe_event_disable(tu, TP_FLAG_PROFILE);
699 return 0;
700#endif
701 default:
702 return 0;
703 }
704 return 0;
705}
706
707static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
708{
709 struct uprobe_trace_consumer *utc;
710 struct trace_uprobe *tu;
711
712 utc = container_of(con, struct uprobe_trace_consumer, cons);
713 tu = utc->tu;
714 if (!tu || tu->consumer != utc)
715 return 0;
716
717 if (tu->flags & TP_FLAG_TRACE)
718 uprobe_trace_func(tu, regs);
719
720#ifdef CONFIG_PERF_EVENTS
721 if (tu->flags & TP_FLAG_PROFILE)
722 uprobe_perf_func(tu, regs);
723#endif
724 return 0;
725}
726
727static struct trace_event_functions uprobe_funcs = {
728 .trace = print_uprobe_event
729};
730
731static int register_uprobe_event(struct trace_uprobe *tu)
732{
733 struct ftrace_event_call *call = &tu->call;
734 int ret;
735
736 /* Initialize ftrace_event_call */
737 INIT_LIST_HEAD(&call->class->fields);
738 call->event.funcs = &uprobe_funcs;
739 call->class->define_fields = uprobe_event_define_fields;
740
741 if (set_print_fmt(tu) < 0)
742 return -ENOMEM;
743
744 ret = register_ftrace_event(&call->event);
745 if (!ret) {
746 kfree(call->print_fmt);
747 return -ENODEV;
748 }
749 call->flags = 0;
750 call->class->reg = trace_uprobe_register;
751 call->data = tu;
752 ret = trace_add_event_call(call);
753
754 if (ret) {
755 pr_info("Failed to register uprobe event: %s\n", call->name);
756 kfree(call->print_fmt);
757 unregister_ftrace_event(&call->event);
758 }
759
760 return ret;
761}
762
763static void unregister_uprobe_event(struct trace_uprobe *tu)
764{
765 /* tu->event is unregistered in trace_remove_event_call() */
766 trace_remove_event_call(&tu->call);
767 kfree(tu->call.print_fmt);
768 tu->call.print_fmt = NULL;
769}
770
771/* Make a trace interface for controling probe points */
772static __init int init_uprobe_trace(void)
773{
774 struct dentry *d_tracer;
775
776 d_tracer = tracing_init_dentry();
777 if (!d_tracer)
778 return 0;
779
780 trace_create_file("uprobe_events", 0644, d_tracer,
781 NULL, &uprobe_events_ops);
782 /* Profile interface */
783 trace_create_file("uprobe_profile", 0444, d_tracer,
784 NULL, &uprobe_profile_ops);
785 return 0;
786}
787
788fs_initcall(init_uprobe_trace);