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TOMOYO Linux Cross Reference
Linux/kernel/trace/trace_uprobe.c

Version: ~ [ linux-4.18-rc5 ] ~ [ linux-4.17.6 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.55 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.112 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.140 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.115 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.57 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.27.62 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  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 #define pr_fmt(fmt)     "trace_kprobe: " fmt
 21 
 22 #include <linux/module.h>
 23 #include <linux/uaccess.h>
 24 #include <linux/uprobes.h>
 25 #include <linux/namei.h>
 26 #include <linux/string.h>
 27 #include <linux/rculist.h>
 28 
 29 #include "trace_probe.h"
 30 
 31 #define UPROBE_EVENT_SYSTEM     "uprobes"
 32 
 33 struct uprobe_trace_entry_head {
 34         struct trace_entry      ent;
 35         unsigned long           vaddr[];
 36 };
 37 
 38 #define SIZEOF_TRACE_ENTRY(is_return)                   \
 39         (sizeof(struct uprobe_trace_entry_head) +       \
 40          sizeof(unsigned long) * (is_return ? 2 : 1))
 41 
 42 #define DATAOF_TRACE_ENTRY(entry, is_return)            \
 43         ((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return))
 44 
 45 struct trace_uprobe_filter {
 46         rwlock_t                rwlock;
 47         int                     nr_systemwide;
 48         struct list_head        perf_events;
 49 };
 50 
 51 /*
 52  * uprobe event core functions
 53  */
 54 struct trace_uprobe {
 55         struct list_head                list;
 56         struct trace_uprobe_filter      filter;
 57         struct uprobe_consumer          consumer;
 58         struct path                     path;
 59         struct inode                    *inode;
 60         char                            *filename;
 61         unsigned long                   offset;
 62         unsigned long                   nhit;
 63         struct trace_probe              tp;
 64 };
 65 
 66 #define SIZEOF_TRACE_UPROBE(n)                          \
 67         (offsetof(struct trace_uprobe, tp.args) +       \
 68         (sizeof(struct probe_arg) * (n)))
 69 
 70 static int register_uprobe_event(struct trace_uprobe *tu);
 71 static int unregister_uprobe_event(struct trace_uprobe *tu);
 72 
 73 static DEFINE_MUTEX(uprobe_lock);
 74 static LIST_HEAD(uprobe_list);
 75 
 76 struct uprobe_dispatch_data {
 77         struct trace_uprobe     *tu;
 78         unsigned long           bp_addr;
 79 };
 80 
 81 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
 82 static int uretprobe_dispatcher(struct uprobe_consumer *con,
 83                                 unsigned long func, struct pt_regs *regs);
 84 
 85 #ifdef CONFIG_STACK_GROWSUP
 86 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
 87 {
 88         return addr - (n * sizeof(long));
 89 }
 90 #else
 91 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
 92 {
 93         return addr + (n * sizeof(long));
 94 }
 95 #endif
 96 
 97 static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n)
 98 {
 99         unsigned long ret;
100         unsigned long addr = user_stack_pointer(regs);
101 
102         addr = adjust_stack_addr(addr, n);
103 
104         if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret)))
105                 return 0;
106 
107         return ret;
108 }
109 
110 /*
111  * Uprobes-specific fetch functions
112  */
113 #define DEFINE_FETCH_stack(type)                                        \
114 static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,          \
115                                          void *offset, void *dest)      \
116 {                                                                       \
117         *(type *)dest = (type)get_user_stack_nth(regs,                  \
118                                               ((unsigned long)offset)); \
119 }
120 DEFINE_BASIC_FETCH_FUNCS(stack)
121 /* No string on the stack entry */
122 #define fetch_stack_string      NULL
123 #define fetch_stack_string_size NULL
124 
125 #define DEFINE_FETCH_memory(type)                                       \
126 static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,         \
127                                           void *addr, void *dest)       \
128 {                                                                       \
129         type retval;                                                    \
130         void __user *vaddr = (void __force __user *) addr;              \
131                                                                         \
132         if (copy_from_user(&retval, vaddr, sizeof(type)))               \
133                 *(type *)dest = 0;                                      \
134         else                                                            \
135                 *(type *) dest = retval;                                \
136 }
137 DEFINE_BASIC_FETCH_FUNCS(memory)
138 /*
139  * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
140  * length and relative data location.
141  */
142 static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
143                                             void *addr, void *dest)
144 {
145         long ret;
146         u32 rloc = *(u32 *)dest;
147         int maxlen  = get_rloc_len(rloc);
148         u8 *dst = get_rloc_data(dest);
149         void __user *src = (void __force __user *) addr;
150 
151         if (!maxlen)
152                 return;
153 
154         ret = strncpy_from_user(dst, src, maxlen);
155         if (ret == maxlen)
156                 dst[--ret] = '\0';
157 
158         if (ret < 0) {  /* Failed to fetch string */
159                 ((u8 *)get_rloc_data(dest))[0] = '\0';
160                 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(rloc));
161         } else {
162                 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(rloc));
163         }
164 }
165 
166 static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
167                                                  void *addr, void *dest)
168 {
169         int len;
170         void __user *vaddr = (void __force __user *) addr;
171 
172         len = strnlen_user(vaddr, MAX_STRING_SIZE);
173 
174         if (len == 0 || len > MAX_STRING_SIZE)  /* Failed to check length */
175                 *(u32 *)dest = 0;
176         else
177                 *(u32 *)dest = len;
178 }
179 
180 static unsigned long translate_user_vaddr(void *file_offset)
181 {
182         unsigned long base_addr;
183         struct uprobe_dispatch_data *udd;
184 
185         udd = (void *) current->utask->vaddr;
186 
187         base_addr = udd->bp_addr - udd->tu->offset;
188         return base_addr + (unsigned long)file_offset;
189 }
190 
191 #define DEFINE_FETCH_file_offset(type)                                  \
192 static void FETCH_FUNC_NAME(file_offset, type)(struct pt_regs *regs,    \
193                                                void *offset, void *dest)\
194 {                                                                       \
195         void *vaddr = (void *)translate_user_vaddr(offset);             \
196                                                                         \
197         FETCH_FUNC_NAME(memory, type)(regs, vaddr, dest);               \
198 }
199 DEFINE_BASIC_FETCH_FUNCS(file_offset)
200 DEFINE_FETCH_file_offset(string)
201 DEFINE_FETCH_file_offset(string_size)
202 
203 /* Fetch type information table */
204 static const struct fetch_type uprobes_fetch_type_table[] = {
205         /* Special types */
206         [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
207                                         sizeof(u32), 1, "__data_loc char[]"),
208         [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
209                                         string_size, sizeof(u32), 0, "u32"),
210         /* Basic types */
211         ASSIGN_FETCH_TYPE(u8,  u8,  0),
212         ASSIGN_FETCH_TYPE(u16, u16, 0),
213         ASSIGN_FETCH_TYPE(u32, u32, 0),
214         ASSIGN_FETCH_TYPE(u64, u64, 0),
215         ASSIGN_FETCH_TYPE(s8,  u8,  1),
216         ASSIGN_FETCH_TYPE(s16, u16, 1),
217         ASSIGN_FETCH_TYPE(s32, u32, 1),
218         ASSIGN_FETCH_TYPE(s64, u64, 1),
219         ASSIGN_FETCH_TYPE_ALIAS(x8,  u8,  u8,  0),
220         ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
221         ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
222         ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
223 
224         ASSIGN_FETCH_TYPE_END
225 };
226 
227 static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter)
228 {
229         rwlock_init(&filter->rwlock);
230         filter->nr_systemwide = 0;
231         INIT_LIST_HEAD(&filter->perf_events);
232 }
233 
234 static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter)
235 {
236         return !filter->nr_systemwide && list_empty(&filter->perf_events);
237 }
238 
239 static inline bool is_ret_probe(struct trace_uprobe *tu)
240 {
241         return tu->consumer.ret_handler != NULL;
242 }
243 
244 /*
245  * Allocate new trace_uprobe and initialize it (including uprobes).
246  */
247 static struct trace_uprobe *
248 alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
249 {
250         struct trace_uprobe *tu;
251 
252         if (!event || !is_good_name(event))
253                 return ERR_PTR(-EINVAL);
254 
255         if (!group || !is_good_name(group))
256                 return ERR_PTR(-EINVAL);
257 
258         tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL);
259         if (!tu)
260                 return ERR_PTR(-ENOMEM);
261 
262         tu->tp.call.class = &tu->tp.class;
263         tu->tp.call.name = kstrdup(event, GFP_KERNEL);
264         if (!tu->tp.call.name)
265                 goto error;
266 
267         tu->tp.class.system = kstrdup(group, GFP_KERNEL);
268         if (!tu->tp.class.system)
269                 goto error;
270 
271         INIT_LIST_HEAD(&tu->list);
272         INIT_LIST_HEAD(&tu->tp.files);
273         tu->consumer.handler = uprobe_dispatcher;
274         if (is_ret)
275                 tu->consumer.ret_handler = uretprobe_dispatcher;
276         init_trace_uprobe_filter(&tu->filter);
277         return tu;
278 
279 error:
280         kfree(tu->tp.call.name);
281         kfree(tu);
282 
283         return ERR_PTR(-ENOMEM);
284 }
285 
286 static void free_trace_uprobe(struct trace_uprobe *tu)
287 {
288         int i;
289 
290         for (i = 0; i < tu->tp.nr_args; i++)
291                 traceprobe_free_probe_arg(&tu->tp.args[i]);
292 
293         path_put(&tu->path);
294         kfree(tu->tp.call.class->system);
295         kfree(tu->tp.call.name);
296         kfree(tu->filename);
297         kfree(tu);
298 }
299 
300 static struct trace_uprobe *find_probe_event(const char *event, const char *group)
301 {
302         struct trace_uprobe *tu;
303 
304         list_for_each_entry(tu, &uprobe_list, list)
305                 if (strcmp(trace_event_name(&tu->tp.call), event) == 0 &&
306                     strcmp(tu->tp.call.class->system, group) == 0)
307                         return tu;
308 
309         return NULL;
310 }
311 
312 /* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */
313 static int unregister_trace_uprobe(struct trace_uprobe *tu)
314 {
315         int ret;
316 
317         ret = unregister_uprobe_event(tu);
318         if (ret)
319                 return ret;
320 
321         list_del(&tu->list);
322         free_trace_uprobe(tu);
323         return 0;
324 }
325 
326 /* Register a trace_uprobe and probe_event */
327 static int register_trace_uprobe(struct trace_uprobe *tu)
328 {
329         struct trace_uprobe *old_tu;
330         int ret;
331 
332         mutex_lock(&uprobe_lock);
333 
334         /* register as an event */
335         old_tu = find_probe_event(trace_event_name(&tu->tp.call),
336                         tu->tp.call.class->system);
337         if (old_tu) {
338                 /* delete old event */
339                 ret = unregister_trace_uprobe(old_tu);
340                 if (ret)
341                         goto end;
342         }
343 
344         ret = register_uprobe_event(tu);
345         if (ret) {
346                 pr_warn("Failed to register probe event(%d)\n", ret);
347                 goto end;
348         }
349 
350         list_add_tail(&tu->list, &uprobe_list);
351 
352 end:
353         mutex_unlock(&uprobe_lock);
354 
355         return ret;
356 }
357 
358 /*
359  * Argument syntax:
360  *  - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS]
361  *
362  *  - Remove uprobe: -:[GRP/]EVENT
363  */
364 static int create_trace_uprobe(int argc, char **argv)
365 {
366         struct trace_uprobe *tu;
367         char *arg, *event, *group, *filename;
368         char buf[MAX_EVENT_NAME_LEN];
369         struct path path;
370         unsigned long offset;
371         bool is_delete, is_return;
372         int i, ret;
373 
374         ret = 0;
375         is_delete = false;
376         is_return = false;
377         event = NULL;
378         group = NULL;
379 
380         /* argc must be >= 1 */
381         if (argv[0][0] == '-')
382                 is_delete = true;
383         else if (argv[0][0] == 'r')
384                 is_return = true;
385         else if (argv[0][0] != 'p') {
386                 pr_info("Probe definition must be started with 'p', 'r' or '-'.\n");
387                 return -EINVAL;
388         }
389 
390         if (argv[0][1] == ':') {
391                 event = &argv[0][2];
392                 arg = strchr(event, '/');
393 
394                 if (arg) {
395                         group = event;
396                         event = arg + 1;
397                         event[-1] = '\0';
398 
399                         if (strlen(group) == 0) {
400                                 pr_info("Group name is not specified\n");
401                                 return -EINVAL;
402                         }
403                 }
404                 if (strlen(event) == 0) {
405                         pr_info("Event name is not specified\n");
406                         return -EINVAL;
407                 }
408         }
409         if (!group)
410                 group = UPROBE_EVENT_SYSTEM;
411 
412         if (is_delete) {
413                 int ret;
414 
415                 if (!event) {
416                         pr_info("Delete command needs an event name.\n");
417                         return -EINVAL;
418                 }
419                 mutex_lock(&uprobe_lock);
420                 tu = find_probe_event(event, group);
421 
422                 if (!tu) {
423                         mutex_unlock(&uprobe_lock);
424                         pr_info("Event %s/%s doesn't exist.\n", group, event);
425                         return -ENOENT;
426                 }
427                 /* delete an event */
428                 ret = unregister_trace_uprobe(tu);
429                 mutex_unlock(&uprobe_lock);
430                 return ret;
431         }
432 
433         if (argc < 2) {
434                 pr_info("Probe point is not specified.\n");
435                 return -EINVAL;
436         }
437         /* Find the last occurrence, in case the path contains ':' too. */
438         arg = strrchr(argv[1], ':');
439         if (!arg)
440                 return -EINVAL;
441 
442         *arg++ = '\0';
443         filename = argv[1];
444         ret = kern_path(filename, LOOKUP_FOLLOW, &path);
445         if (ret)
446                 return ret;
447 
448         if (!d_is_reg(path.dentry)) {
449                 ret = -EINVAL;
450                 goto fail_address_parse;
451         }
452 
453         ret = kstrtoul(arg, 0, &offset);
454         if (ret)
455                 goto fail_address_parse;
456 
457         argc -= 2;
458         argv += 2;
459 
460         /* setup a probe */
461         if (!event) {
462                 char *tail;
463                 char *ptr;
464 
465                 tail = kstrdup(kbasename(filename), GFP_KERNEL);
466                 if (!tail) {
467                         ret = -ENOMEM;
468                         goto fail_address_parse;
469                 }
470 
471                 ptr = strpbrk(tail, ".-_");
472                 if (ptr)
473                         *ptr = '\0';
474 
475                 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
476                 event = buf;
477                 kfree(tail);
478         }
479 
480         tu = alloc_trace_uprobe(group, event, argc, is_return);
481         if (IS_ERR(tu)) {
482                 pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu));
483                 ret = PTR_ERR(tu);
484                 goto fail_address_parse;
485         }
486         tu->offset = offset;
487         tu->path = path;
488         tu->filename = kstrdup(filename, GFP_KERNEL);
489 
490         if (!tu->filename) {
491                 pr_info("Failed to allocate filename.\n");
492                 ret = -ENOMEM;
493                 goto error;
494         }
495 
496         /* parse arguments */
497         ret = 0;
498         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
499                 struct probe_arg *parg = &tu->tp.args[i];
500 
501                 /* Increment count for freeing args in error case */
502                 tu->tp.nr_args++;
503 
504                 /* Parse argument name */
505                 arg = strchr(argv[i], '=');
506                 if (arg) {
507                         *arg++ = '\0';
508                         parg->name = kstrdup(argv[i], GFP_KERNEL);
509                 } else {
510                         arg = argv[i];
511                         /* If argument name is omitted, set "argN" */
512                         snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
513                         parg->name = kstrdup(buf, GFP_KERNEL);
514                 }
515 
516                 if (!parg->name) {
517                         pr_info("Failed to allocate argument[%d] name.\n", i);
518                         ret = -ENOMEM;
519                         goto error;
520                 }
521 
522                 if (!is_good_name(parg->name)) {
523                         pr_info("Invalid argument[%d] name: %s\n", i, parg->name);
524                         ret = -EINVAL;
525                         goto error;
526                 }
527 
528                 if (traceprobe_conflict_field_name(parg->name, tu->tp.args, i)) {
529                         pr_info("Argument[%d] name '%s' conflicts with "
530                                 "another field.\n", i, argv[i]);
531                         ret = -EINVAL;
532                         goto error;
533                 }
534 
535                 /* Parse fetch argument */
536                 ret = traceprobe_parse_probe_arg(arg, &tu->tp.size, parg,
537                                                  is_return, false,
538                                                  uprobes_fetch_type_table);
539                 if (ret) {
540                         pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
541                         goto error;
542                 }
543         }
544 
545         ret = register_trace_uprobe(tu);
546         if (ret)
547                 goto error;
548         return 0;
549 
550 error:
551         free_trace_uprobe(tu);
552         return ret;
553 
554 fail_address_parse:
555         path_put(&path);
556 
557         pr_info("Failed to parse address or file.\n");
558 
559         return ret;
560 }
561 
562 static int cleanup_all_probes(void)
563 {
564         struct trace_uprobe *tu;
565         int ret = 0;
566 
567         mutex_lock(&uprobe_lock);
568         while (!list_empty(&uprobe_list)) {
569                 tu = list_entry(uprobe_list.next, struct trace_uprobe, list);
570                 ret = unregister_trace_uprobe(tu);
571                 if (ret)
572                         break;
573         }
574         mutex_unlock(&uprobe_lock);
575         return ret;
576 }
577 
578 /* Probes listing interfaces */
579 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
580 {
581         mutex_lock(&uprobe_lock);
582         return seq_list_start(&uprobe_list, *pos);
583 }
584 
585 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
586 {
587         return seq_list_next(v, &uprobe_list, pos);
588 }
589 
590 static void probes_seq_stop(struct seq_file *m, void *v)
591 {
592         mutex_unlock(&uprobe_lock);
593 }
594 
595 static int probes_seq_show(struct seq_file *m, void *v)
596 {
597         struct trace_uprobe *tu = v;
598         char c = is_ret_probe(tu) ? 'r' : 'p';
599         int i;
600 
601         seq_printf(m, "%c:%s/%s %s:0x%0*lx", c, tu->tp.call.class->system,
602                         trace_event_name(&tu->tp.call), tu->filename,
603                         (int)(sizeof(void *) * 2), tu->offset);
604 
605         for (i = 0; i < tu->tp.nr_args; i++)
606                 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm);
607 
608         seq_putc(m, '\n');
609         return 0;
610 }
611 
612 static const struct seq_operations probes_seq_op = {
613         .start  = probes_seq_start,
614         .next   = probes_seq_next,
615         .stop   = probes_seq_stop,
616         .show   = probes_seq_show
617 };
618 
619 static int probes_open(struct inode *inode, struct file *file)
620 {
621         int ret;
622 
623         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
624                 ret = cleanup_all_probes();
625                 if (ret)
626                         return ret;
627         }
628 
629         return seq_open(file, &probes_seq_op);
630 }
631 
632 static ssize_t probes_write(struct file *file, const char __user *buffer,
633                             size_t count, loff_t *ppos)
634 {
635         return trace_parse_run_command(file, buffer, count, ppos, create_trace_uprobe);
636 }
637 
638 static const struct file_operations uprobe_events_ops = {
639         .owner          = THIS_MODULE,
640         .open           = probes_open,
641         .read           = seq_read,
642         .llseek         = seq_lseek,
643         .release        = seq_release,
644         .write          = probes_write,
645 };
646 
647 /* Probes profiling interfaces */
648 static int probes_profile_seq_show(struct seq_file *m, void *v)
649 {
650         struct trace_uprobe *tu = v;
651 
652         seq_printf(m, "  %s %-44s %15lu\n", tu->filename,
653                         trace_event_name(&tu->tp.call), tu->nhit);
654         return 0;
655 }
656 
657 static const struct seq_operations profile_seq_op = {
658         .start  = probes_seq_start,
659         .next   = probes_seq_next,
660         .stop   = probes_seq_stop,
661         .show   = probes_profile_seq_show
662 };
663 
664 static int profile_open(struct inode *inode, struct file *file)
665 {
666         return seq_open(file, &profile_seq_op);
667 }
668 
669 static const struct file_operations uprobe_profile_ops = {
670         .owner          = THIS_MODULE,
671         .open           = profile_open,
672         .read           = seq_read,
673         .llseek         = seq_lseek,
674         .release        = seq_release,
675 };
676 
677 struct uprobe_cpu_buffer {
678         struct mutex mutex;
679         void *buf;
680 };
681 static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer;
682 static int uprobe_buffer_refcnt;
683 
684 static int uprobe_buffer_init(void)
685 {
686         int cpu, err_cpu;
687 
688         uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer);
689         if (uprobe_cpu_buffer == NULL)
690                 return -ENOMEM;
691 
692         for_each_possible_cpu(cpu) {
693                 struct page *p = alloc_pages_node(cpu_to_node(cpu),
694                                                   GFP_KERNEL, 0);
695                 if (p == NULL) {
696                         err_cpu = cpu;
697                         goto err;
698                 }
699                 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p);
700                 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex);
701         }
702 
703         return 0;
704 
705 err:
706         for_each_possible_cpu(cpu) {
707                 if (cpu == err_cpu)
708                         break;
709                 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf);
710         }
711 
712         free_percpu(uprobe_cpu_buffer);
713         return -ENOMEM;
714 }
715 
716 static int uprobe_buffer_enable(void)
717 {
718         int ret = 0;
719 
720         BUG_ON(!mutex_is_locked(&event_mutex));
721 
722         if (uprobe_buffer_refcnt++ == 0) {
723                 ret = uprobe_buffer_init();
724                 if (ret < 0)
725                         uprobe_buffer_refcnt--;
726         }
727 
728         return ret;
729 }
730 
731 static void uprobe_buffer_disable(void)
732 {
733         int cpu;
734 
735         BUG_ON(!mutex_is_locked(&event_mutex));
736 
737         if (--uprobe_buffer_refcnt == 0) {
738                 for_each_possible_cpu(cpu)
739                         free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer,
740                                                              cpu)->buf);
741 
742                 free_percpu(uprobe_cpu_buffer);
743                 uprobe_cpu_buffer = NULL;
744         }
745 }
746 
747 static struct uprobe_cpu_buffer *uprobe_buffer_get(void)
748 {
749         struct uprobe_cpu_buffer *ucb;
750         int cpu;
751 
752         cpu = raw_smp_processor_id();
753         ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu);
754 
755         /*
756          * Use per-cpu buffers for fastest access, but we might migrate
757          * so the mutex makes sure we have sole access to it.
758          */
759         mutex_lock(&ucb->mutex);
760 
761         return ucb;
762 }
763 
764 static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb)
765 {
766         mutex_unlock(&ucb->mutex);
767 }
768 
769 static void __uprobe_trace_func(struct trace_uprobe *tu,
770                                 unsigned long func, struct pt_regs *regs,
771                                 struct uprobe_cpu_buffer *ucb, int dsize,
772                                 struct trace_event_file *trace_file)
773 {
774         struct uprobe_trace_entry_head *entry;
775         struct ring_buffer_event *event;
776         struct ring_buffer *buffer;
777         void *data;
778         int size, esize;
779         struct trace_event_call *call = &tu->tp.call;
780 
781         WARN_ON(call != trace_file->event_call);
782 
783         if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE))
784                 return;
785 
786         if (trace_trigger_soft_disabled(trace_file))
787                 return;
788 
789         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
790         size = esize + tu->tp.size + dsize;
791         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
792                                                 call->event.type, size, 0, 0);
793         if (!event)
794                 return;
795 
796         entry = ring_buffer_event_data(event);
797         if (is_ret_probe(tu)) {
798                 entry->vaddr[0] = func;
799                 entry->vaddr[1] = instruction_pointer(regs);
800                 data = DATAOF_TRACE_ENTRY(entry, true);
801         } else {
802                 entry->vaddr[0] = instruction_pointer(regs);
803                 data = DATAOF_TRACE_ENTRY(entry, false);
804         }
805 
806         memcpy(data, ucb->buf, tu->tp.size + dsize);
807 
808         event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0);
809 }
810 
811 /* uprobe handler */
812 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs,
813                              struct uprobe_cpu_buffer *ucb, int dsize)
814 {
815         struct event_file_link *link;
816 
817         if (is_ret_probe(tu))
818                 return 0;
819 
820         rcu_read_lock();
821         list_for_each_entry_rcu(link, &tu->tp.files, list)
822                 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file);
823         rcu_read_unlock();
824 
825         return 0;
826 }
827 
828 static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func,
829                                  struct pt_regs *regs,
830                                  struct uprobe_cpu_buffer *ucb, int dsize)
831 {
832         struct event_file_link *link;
833 
834         rcu_read_lock();
835         list_for_each_entry_rcu(link, &tu->tp.files, list)
836                 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file);
837         rcu_read_unlock();
838 }
839 
840 /* Event entry printers */
841 static enum print_line_t
842 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
843 {
844         struct uprobe_trace_entry_head *entry;
845         struct trace_seq *s = &iter->seq;
846         struct trace_uprobe *tu;
847         u8 *data;
848         int i;
849 
850         entry = (struct uprobe_trace_entry_head *)iter->ent;
851         tu = container_of(event, struct trace_uprobe, tp.call.event);
852 
853         if (is_ret_probe(tu)) {
854                 trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
855                                  trace_event_name(&tu->tp.call),
856                                  entry->vaddr[1], entry->vaddr[0]);
857                 data = DATAOF_TRACE_ENTRY(entry, true);
858         } else {
859                 trace_seq_printf(s, "%s: (0x%lx)",
860                                  trace_event_name(&tu->tp.call),
861                                  entry->vaddr[0]);
862                 data = DATAOF_TRACE_ENTRY(entry, false);
863         }
864 
865         for (i = 0; i < tu->tp.nr_args; i++) {
866                 struct probe_arg *parg = &tu->tp.args[i];
867 
868                 if (!parg->type->print(s, parg->name, data + parg->offset, entry))
869                         goto out;
870         }
871 
872         trace_seq_putc(s, '\n');
873 
874  out:
875         return trace_handle_return(s);
876 }
877 
878 typedef bool (*filter_func_t)(struct uprobe_consumer *self,
879                                 enum uprobe_filter_ctx ctx,
880                                 struct mm_struct *mm);
881 
882 static int
883 probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file,
884                    filter_func_t filter)
885 {
886         bool enabled = trace_probe_is_enabled(&tu->tp);
887         struct event_file_link *link = NULL;
888         int ret;
889 
890         if (file) {
891                 if (tu->tp.flags & TP_FLAG_PROFILE)
892                         return -EINTR;
893 
894                 link = kmalloc(sizeof(*link), GFP_KERNEL);
895                 if (!link)
896                         return -ENOMEM;
897 
898                 link->file = file;
899                 list_add_tail_rcu(&link->list, &tu->tp.files);
900 
901                 tu->tp.flags |= TP_FLAG_TRACE;
902         } else {
903                 if (tu->tp.flags & TP_FLAG_TRACE)
904                         return -EINTR;
905 
906                 tu->tp.flags |= TP_FLAG_PROFILE;
907         }
908 
909         WARN_ON(!uprobe_filter_is_empty(&tu->filter));
910 
911         if (enabled)
912                 return 0;
913 
914         ret = uprobe_buffer_enable();
915         if (ret)
916                 goto err_flags;
917 
918         tu->consumer.filter = filter;
919         tu->inode = d_real_inode(tu->path.dentry);
920         ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
921         if (ret)
922                 goto err_buffer;
923 
924         return 0;
925 
926  err_buffer:
927         uprobe_buffer_disable();
928 
929  err_flags:
930         if (file) {
931                 list_del(&link->list);
932                 kfree(link);
933                 tu->tp.flags &= ~TP_FLAG_TRACE;
934         } else {
935                 tu->tp.flags &= ~TP_FLAG_PROFILE;
936         }
937         return ret;
938 }
939 
940 static void
941 probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file)
942 {
943         if (!trace_probe_is_enabled(&tu->tp))
944                 return;
945 
946         if (file) {
947                 struct event_file_link *link;
948 
949                 link = find_event_file_link(&tu->tp, file);
950                 if (!link)
951                         return;
952 
953                 list_del_rcu(&link->list);
954                 /* synchronize with u{,ret}probe_trace_func */
955                 synchronize_sched();
956                 kfree(link);
957 
958                 if (!list_empty(&tu->tp.files))
959                         return;
960         }
961 
962         WARN_ON(!uprobe_filter_is_empty(&tu->filter));
963 
964         uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
965         tu->inode = NULL;
966         tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE;
967 
968         uprobe_buffer_disable();
969 }
970 
971 static int uprobe_event_define_fields(struct trace_event_call *event_call)
972 {
973         int ret, i, size;
974         struct uprobe_trace_entry_head field;
975         struct trace_uprobe *tu = event_call->data;
976 
977         if (is_ret_probe(tu)) {
978                 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0);
979                 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0);
980                 size = SIZEOF_TRACE_ENTRY(true);
981         } else {
982                 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0);
983                 size = SIZEOF_TRACE_ENTRY(false);
984         }
985         /* Set argument names as fields */
986         for (i = 0; i < tu->tp.nr_args; i++) {
987                 struct probe_arg *parg = &tu->tp.args[i];
988 
989                 ret = trace_define_field(event_call, parg->type->fmttype,
990                                          parg->name, size + parg->offset,
991                                          parg->type->size, parg->type->is_signed,
992                                          FILTER_OTHER);
993 
994                 if (ret)
995                         return ret;
996         }
997         return 0;
998 }
999 
1000 #ifdef CONFIG_PERF_EVENTS
1001 static bool
1002 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
1003 {
1004         struct perf_event *event;
1005 
1006         if (filter->nr_systemwide)
1007                 return true;
1008 
1009         list_for_each_entry(event, &filter->perf_events, hw.tp_list) {
1010                 if (event->hw.target->mm == mm)
1011                         return true;
1012         }
1013 
1014         return false;
1015 }
1016 
1017 static inline bool
1018 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event)
1019 {
1020         return __uprobe_perf_filter(&tu->filter, event->hw.target->mm);
1021 }
1022 
1023 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event)
1024 {
1025         bool done;
1026 
1027         write_lock(&tu->filter.rwlock);
1028         if (event->hw.target) {
1029                 list_del(&event->hw.tp_list);
1030                 done = tu->filter.nr_systemwide ||
1031                         (event->hw.target->flags & PF_EXITING) ||
1032                         uprobe_filter_event(tu, event);
1033         } else {
1034                 tu->filter.nr_systemwide--;
1035                 done = tu->filter.nr_systemwide;
1036         }
1037         write_unlock(&tu->filter.rwlock);
1038 
1039         if (!done)
1040                 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
1041 
1042         return 0;
1043 }
1044 
1045 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
1046 {
1047         bool done;
1048         int err;
1049 
1050         write_lock(&tu->filter.rwlock);
1051         if (event->hw.target) {
1052                 /*
1053                  * event->parent != NULL means copy_process(), we can avoid
1054                  * uprobe_apply(). current->mm must be probed and we can rely
1055                  * on dup_mmap() which preserves the already installed bp's.
1056                  *
1057                  * attr.enable_on_exec means that exec/mmap will install the
1058                  * breakpoints we need.
1059                  */
1060                 done = tu->filter.nr_systemwide ||
1061                         event->parent || event->attr.enable_on_exec ||
1062                         uprobe_filter_event(tu, event);
1063                 list_add(&event->hw.tp_list, &tu->filter.perf_events);
1064         } else {
1065                 done = tu->filter.nr_systemwide;
1066                 tu->filter.nr_systemwide++;
1067         }
1068         write_unlock(&tu->filter.rwlock);
1069 
1070         err = 0;
1071         if (!done) {
1072                 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
1073                 if (err)
1074                         uprobe_perf_close(tu, event);
1075         }
1076         return err;
1077 }
1078 
1079 static bool uprobe_perf_filter(struct uprobe_consumer *uc,
1080                                 enum uprobe_filter_ctx ctx, struct mm_struct *mm)
1081 {
1082         struct trace_uprobe *tu;
1083         int ret;
1084 
1085         tu = container_of(uc, struct trace_uprobe, consumer);
1086         read_lock(&tu->filter.rwlock);
1087         ret = __uprobe_perf_filter(&tu->filter, mm);
1088         read_unlock(&tu->filter.rwlock);
1089 
1090         return ret;
1091 }
1092 
1093 static void __uprobe_perf_func(struct trace_uprobe *tu,
1094                                unsigned long func, struct pt_regs *regs,
1095                                struct uprobe_cpu_buffer *ucb, int dsize)
1096 {
1097         struct trace_event_call *call = &tu->tp.call;
1098         struct uprobe_trace_entry_head *entry;
1099         struct hlist_head *head;
1100         void *data;
1101         int size, esize;
1102         int rctx;
1103 
1104         if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1105                 return;
1106 
1107         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1108 
1109         size = esize + tu->tp.size + dsize;
1110         size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32);
1111         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
1112                 return;
1113 
1114         preempt_disable();
1115         head = this_cpu_ptr(call->perf_events);
1116         if (hlist_empty(head))
1117                 goto out;
1118 
1119         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1120         if (!entry)
1121                 goto out;
1122 
1123         if (is_ret_probe(tu)) {
1124                 entry->vaddr[0] = func;
1125                 entry->vaddr[1] = instruction_pointer(regs);
1126                 data = DATAOF_TRACE_ENTRY(entry, true);
1127         } else {
1128                 entry->vaddr[0] = instruction_pointer(regs);
1129                 data = DATAOF_TRACE_ENTRY(entry, false);
1130         }
1131 
1132         memcpy(data, ucb->buf, tu->tp.size + dsize);
1133 
1134         if (size - esize > tu->tp.size + dsize) {
1135                 int len = tu->tp.size + dsize;
1136 
1137                 memset(data + len, 0, size - esize - len);
1138         }
1139 
1140         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1141                               head, NULL);
1142  out:
1143         preempt_enable();
1144 }
1145 
1146 /* uprobe profile handler */
1147 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs,
1148                             struct uprobe_cpu_buffer *ucb, int dsize)
1149 {
1150         if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
1151                 return UPROBE_HANDLER_REMOVE;
1152 
1153         if (!is_ret_probe(tu))
1154                 __uprobe_perf_func(tu, 0, regs, ucb, dsize);
1155         return 0;
1156 }
1157 
1158 static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func,
1159                                 struct pt_regs *regs,
1160                                 struct uprobe_cpu_buffer *ucb, int dsize)
1161 {
1162         __uprobe_perf_func(tu, func, regs, ucb, dsize);
1163 }
1164 
1165 int bpf_get_uprobe_info(const struct perf_event *event, u32 *fd_type,
1166                         const char **filename, u64 *probe_offset,
1167                         bool perf_type_tracepoint)
1168 {
1169         const char *pevent = trace_event_name(event->tp_event);
1170         const char *group = event->tp_event->class->system;
1171         struct trace_uprobe *tu;
1172 
1173         if (perf_type_tracepoint)
1174                 tu = find_probe_event(pevent, group);
1175         else
1176                 tu = event->tp_event->data;
1177         if (!tu)
1178                 return -EINVAL;
1179 
1180         *fd_type = is_ret_probe(tu) ? BPF_FD_TYPE_URETPROBE
1181                                     : BPF_FD_TYPE_UPROBE;
1182         *filename = tu->filename;
1183         *probe_offset = tu->offset;
1184         return 0;
1185 }
1186 #endif  /* CONFIG_PERF_EVENTS */
1187 
1188 static int
1189 trace_uprobe_register(struct trace_event_call *event, enum trace_reg type,
1190                       void *data)
1191 {
1192         struct trace_uprobe *tu = event->data;
1193         struct trace_event_file *file = data;
1194 
1195         switch (type) {
1196         case TRACE_REG_REGISTER:
1197                 return probe_event_enable(tu, file, NULL);
1198 
1199         case TRACE_REG_UNREGISTER:
1200                 probe_event_disable(tu, file);
1201                 return 0;
1202 
1203 #ifdef CONFIG_PERF_EVENTS
1204         case TRACE_REG_PERF_REGISTER:
1205                 return probe_event_enable(tu, NULL, uprobe_perf_filter);
1206 
1207         case TRACE_REG_PERF_UNREGISTER:
1208                 probe_event_disable(tu, NULL);
1209                 return 0;
1210 
1211         case TRACE_REG_PERF_OPEN:
1212                 return uprobe_perf_open(tu, data);
1213 
1214         case TRACE_REG_PERF_CLOSE:
1215                 return uprobe_perf_close(tu, data);
1216 
1217 #endif
1218         default:
1219                 return 0;
1220         }
1221         return 0;
1222 }
1223 
1224 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
1225 {
1226         struct trace_uprobe *tu;
1227         struct uprobe_dispatch_data udd;
1228         struct uprobe_cpu_buffer *ucb;
1229         int dsize, esize;
1230         int ret = 0;
1231 
1232 
1233         tu = container_of(con, struct trace_uprobe, consumer);
1234         tu->nhit++;
1235 
1236         udd.tu = tu;
1237         udd.bp_addr = instruction_pointer(regs);
1238 
1239         current->utask->vaddr = (unsigned long) &udd;
1240 
1241         if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1242                 return 0;
1243 
1244         dsize = __get_data_size(&tu->tp, regs);
1245         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1246 
1247         ucb = uprobe_buffer_get();
1248         store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
1249 
1250         if (tu->tp.flags & TP_FLAG_TRACE)
1251                 ret |= uprobe_trace_func(tu, regs, ucb, dsize);
1252 
1253 #ifdef CONFIG_PERF_EVENTS
1254         if (tu->tp.flags & TP_FLAG_PROFILE)
1255                 ret |= uprobe_perf_func(tu, regs, ucb, dsize);
1256 #endif
1257         uprobe_buffer_put(ucb);
1258         return ret;
1259 }
1260 
1261 static int uretprobe_dispatcher(struct uprobe_consumer *con,
1262                                 unsigned long func, struct pt_regs *regs)
1263 {
1264         struct trace_uprobe *tu;
1265         struct uprobe_dispatch_data udd;
1266         struct uprobe_cpu_buffer *ucb;
1267         int dsize, esize;
1268 
1269         tu = container_of(con, struct trace_uprobe, consumer);
1270 
1271         udd.tu = tu;
1272         udd.bp_addr = func;
1273 
1274         current->utask->vaddr = (unsigned long) &udd;
1275 
1276         if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1277                 return 0;
1278 
1279         dsize = __get_data_size(&tu->tp, regs);
1280         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1281 
1282         ucb = uprobe_buffer_get();
1283         store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
1284 
1285         if (tu->tp.flags & TP_FLAG_TRACE)
1286                 uretprobe_trace_func(tu, func, regs, ucb, dsize);
1287 
1288 #ifdef CONFIG_PERF_EVENTS
1289         if (tu->tp.flags & TP_FLAG_PROFILE)
1290                 uretprobe_perf_func(tu, func, regs, ucb, dsize);
1291 #endif
1292         uprobe_buffer_put(ucb);
1293         return 0;
1294 }
1295 
1296 static struct trace_event_functions uprobe_funcs = {
1297         .trace          = print_uprobe_event
1298 };
1299 
1300 static inline void init_trace_event_call(struct trace_uprobe *tu,
1301                                          struct trace_event_call *call)
1302 {
1303         INIT_LIST_HEAD(&call->class->fields);
1304         call->event.funcs = &uprobe_funcs;
1305         call->class->define_fields = uprobe_event_define_fields;
1306 
1307         call->flags = TRACE_EVENT_FL_UPROBE;
1308         call->class->reg = trace_uprobe_register;
1309         call->data = tu;
1310 }
1311 
1312 static int register_uprobe_event(struct trace_uprobe *tu)
1313 {
1314         struct trace_event_call *call = &tu->tp.call;
1315         int ret = 0;
1316 
1317         init_trace_event_call(tu, call);
1318 
1319         if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0)
1320                 return -ENOMEM;
1321 
1322         ret = register_trace_event(&call->event);
1323         if (!ret) {
1324                 kfree(call->print_fmt);
1325                 return -ENODEV;
1326         }
1327 
1328         ret = trace_add_event_call(call);
1329 
1330         if (ret) {
1331                 pr_info("Failed to register uprobe event: %s\n",
1332                         trace_event_name(call));
1333                 kfree(call->print_fmt);
1334                 unregister_trace_event(&call->event);
1335         }
1336 
1337         return ret;
1338 }
1339 
1340 static int unregister_uprobe_event(struct trace_uprobe *tu)
1341 {
1342         int ret;
1343 
1344         /* tu->event is unregistered in trace_remove_event_call() */
1345         ret = trace_remove_event_call(&tu->tp.call);
1346         if (ret)
1347                 return ret;
1348         kfree(tu->tp.call.print_fmt);
1349         tu->tp.call.print_fmt = NULL;
1350         return 0;
1351 }
1352 
1353 #ifdef CONFIG_PERF_EVENTS
1354 struct trace_event_call *
1355 create_local_trace_uprobe(char *name, unsigned long offs, bool is_return)
1356 {
1357         struct trace_uprobe *tu;
1358         struct path path;
1359         int ret;
1360 
1361         ret = kern_path(name, LOOKUP_FOLLOW, &path);
1362         if (ret)
1363                 return ERR_PTR(ret);
1364 
1365         if (!d_is_reg(path.dentry)) {
1366                 path_put(&path);
1367                 return ERR_PTR(-EINVAL);
1368         }
1369 
1370         /*
1371          * local trace_kprobes are not added to probe_list, so they are never
1372          * searched in find_trace_kprobe(). Therefore, there is no concern of
1373          * duplicated name "DUMMY_EVENT" here.
1374          */
1375         tu = alloc_trace_uprobe(UPROBE_EVENT_SYSTEM, "DUMMY_EVENT", 0,
1376                                 is_return);
1377 
1378         if (IS_ERR(tu)) {
1379                 pr_info("Failed to allocate trace_uprobe.(%d)\n",
1380                         (int)PTR_ERR(tu));
1381                 path_put(&path);
1382                 return ERR_CAST(tu);
1383         }
1384 
1385         tu->offset = offs;
1386         tu->path = path;
1387         tu->filename = kstrdup(name, GFP_KERNEL);
1388         init_trace_event_call(tu, &tu->tp.call);
1389 
1390         if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) {
1391                 ret = -ENOMEM;
1392                 goto error;
1393         }
1394 
1395         return &tu->tp.call;
1396 error:
1397         free_trace_uprobe(tu);
1398         return ERR_PTR(ret);
1399 }
1400 
1401 void destroy_local_trace_uprobe(struct trace_event_call *event_call)
1402 {
1403         struct trace_uprobe *tu;
1404 
1405         tu = container_of(event_call, struct trace_uprobe, tp.call);
1406 
1407         kfree(tu->tp.call.print_fmt);
1408         tu->tp.call.print_fmt = NULL;
1409 
1410         free_trace_uprobe(tu);
1411 }
1412 #endif /* CONFIG_PERF_EVENTS */
1413 
1414 /* Make a trace interface for controling probe points */
1415 static __init int init_uprobe_trace(void)
1416 {
1417         struct dentry *d_tracer;
1418 
1419         d_tracer = tracing_init_dentry();
1420         if (IS_ERR(d_tracer))
1421                 return 0;
1422 
1423         trace_create_file("uprobe_events", 0644, d_tracer,
1424                                     NULL, &uprobe_events_ops);
1425         /* Profile interface */
1426         trace_create_file("uprobe_profile", 0444, d_tracer,
1427                                     NULL, &uprobe_profile_ops);
1428         return 0;
1429 }
1430 
1431 fs_initcall(init_uprobe_trace);
1432 

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