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

Version: ~ [ linux-5.16-rc3 ] ~ [ linux-5.15.5 ] ~ [ linux-5.14.21 ] ~ [ linux-5.13.19 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.82 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.162 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.218 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.256 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.291 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.293 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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  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 #include <linux/string.h>
 26 
 27 #include "trace_probe.h"
 28 
 29 #define UPROBE_EVENT_SYSTEM     "uprobes"
 30 
 31 struct uprobe_trace_entry_head {
 32         struct trace_entry      ent;
 33         unsigned long           vaddr[];
 34 };
 35 
 36 #define SIZEOF_TRACE_ENTRY(is_return)                   \
 37         (sizeof(struct uprobe_trace_entry_head) +       \
 38          sizeof(unsigned long) * (is_return ? 2 : 1))
 39 
 40 #define DATAOF_TRACE_ENTRY(entry, is_return)            \
 41         ((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return))
 42 
 43 struct trace_uprobe_filter {
 44         rwlock_t                rwlock;
 45         int                     nr_systemwide;
 46         struct list_head        perf_events;
 47 };
 48 
 49 /*
 50  * uprobe event core functions
 51  */
 52 struct trace_uprobe {
 53         struct list_head                list;
 54         struct trace_uprobe_filter      filter;
 55         struct uprobe_consumer          consumer;
 56         struct inode                    *inode;
 57         char                            *filename;
 58         unsigned long                   offset;
 59         unsigned long                   nhit;
 60         struct trace_probe              tp;
 61 };
 62 
 63 #define SIZEOF_TRACE_UPROBE(n)                          \
 64         (offsetof(struct trace_uprobe, tp.args) +       \
 65         (sizeof(struct probe_arg) * (n)))
 66 
 67 static int register_uprobe_event(struct trace_uprobe *tu);
 68 static int unregister_uprobe_event(struct trace_uprobe *tu);
 69 
 70 static DEFINE_MUTEX(uprobe_lock);
 71 static LIST_HEAD(uprobe_list);
 72 
 73 struct uprobe_dispatch_data {
 74         struct trace_uprobe     *tu;
 75         unsigned long           bp_addr;
 76 };
 77 
 78 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
 79 static int uretprobe_dispatcher(struct uprobe_consumer *con,
 80                                 unsigned long func, struct pt_regs *regs);
 81 
 82 #ifdef CONFIG_STACK_GROWSUP
 83 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
 84 {
 85         return addr - (n * sizeof(long));
 86 }
 87 #else
 88 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
 89 {
 90         return addr + (n * sizeof(long));
 91 }
 92 #endif
 93 
 94 static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n)
 95 {
 96         unsigned long ret;
 97         unsigned long addr = user_stack_pointer(regs);
 98 
 99         addr = adjust_stack_addr(addr, n);
100 
101         if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret)))
102                 return 0;
103 
104         return ret;
105 }
106 
107 /*
108  * Uprobes-specific fetch functions
109  */
110 #define DEFINE_FETCH_stack(type)                                        \
111 static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,          \
112                                          void *offset, void *dest)      \
113 {                                                                       \
114         *(type *)dest = (type)get_user_stack_nth(regs,                  \
115                                               ((unsigned long)offset)); \
116 }
117 DEFINE_BASIC_FETCH_FUNCS(stack)
118 /* No string on the stack entry */
119 #define fetch_stack_string      NULL
120 #define fetch_stack_string_size NULL
121 
122 #define DEFINE_FETCH_memory(type)                                       \
123 static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,         \
124                                           void *addr, void *dest)       \
125 {                                                                       \
126         type retval;                                                    \
127         void __user *vaddr = (void __force __user *) addr;              \
128                                                                         \
129         if (copy_from_user(&retval, vaddr, sizeof(type)))               \
130                 *(type *)dest = 0;                                      \
131         else                                                            \
132                 *(type *) dest = retval;                                \
133 }
134 DEFINE_BASIC_FETCH_FUNCS(memory)
135 /*
136  * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
137  * length and relative data location.
138  */
139 static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
140                                             void *addr, void *dest)
141 {
142         long ret;
143         u32 rloc = *(u32 *)dest;
144         int maxlen  = get_rloc_len(rloc);
145         u8 *dst = get_rloc_data(dest);
146         void __user *src = (void __force __user *) addr;
147 
148         if (!maxlen)
149                 return;
150 
151         ret = strncpy_from_user(dst, src, maxlen);
152 
153         if (ret < 0) {  /* Failed to fetch string */
154                 ((u8 *)get_rloc_data(dest))[0] = '\0';
155                 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(rloc));
156         } else {
157                 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(rloc));
158         }
159 }
160 
161 static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
162                                                  void *addr, void *dest)
163 {
164         int len;
165         void __user *vaddr = (void __force __user *) addr;
166 
167         len = strnlen_user(vaddr, MAX_STRING_SIZE);
168 
169         if (len == 0 || len > MAX_STRING_SIZE)  /* Failed to check length */
170                 *(u32 *)dest = 0;
171         else
172                 *(u32 *)dest = len;
173 }
174 
175 static unsigned long translate_user_vaddr(void *file_offset)
176 {
177         unsigned long base_addr;
178         struct uprobe_dispatch_data *udd;
179 
180         udd = (void *) current->utask->vaddr;
181 
182         base_addr = udd->bp_addr - udd->tu->offset;
183         return base_addr + (unsigned long)file_offset;
184 }
185 
186 #define DEFINE_FETCH_file_offset(type)                                  \
187 static void FETCH_FUNC_NAME(file_offset, type)(struct pt_regs *regs,    \
188                                                void *offset, void *dest)\
189 {                                                                       \
190         void *vaddr = (void *)translate_user_vaddr(offset);             \
191                                                                         \
192         FETCH_FUNC_NAME(memory, type)(regs, vaddr, dest);               \
193 }
194 DEFINE_BASIC_FETCH_FUNCS(file_offset)
195 DEFINE_FETCH_file_offset(string)
196 DEFINE_FETCH_file_offset(string_size)
197 
198 /* Fetch type information table */
199 static const struct fetch_type uprobes_fetch_type_table[] = {
200         /* Special types */
201         [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
202                                         sizeof(u32), 1, "__data_loc char[]"),
203         [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
204                                         string_size, sizeof(u32), 0, "u32"),
205         /* Basic types */
206         ASSIGN_FETCH_TYPE(u8,  u8,  0),
207         ASSIGN_FETCH_TYPE(u16, u16, 0),
208         ASSIGN_FETCH_TYPE(u32, u32, 0),
209         ASSIGN_FETCH_TYPE(u64, u64, 0),
210         ASSIGN_FETCH_TYPE(s8,  u8,  1),
211         ASSIGN_FETCH_TYPE(s16, u16, 1),
212         ASSIGN_FETCH_TYPE(s32, u32, 1),
213         ASSIGN_FETCH_TYPE(s64, u64, 1),
214 
215         ASSIGN_FETCH_TYPE_END
216 };
217 
218 static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter)
219 {
220         rwlock_init(&filter->rwlock);
221         filter->nr_systemwide = 0;
222         INIT_LIST_HEAD(&filter->perf_events);
223 }
224 
225 static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter)
226 {
227         return !filter->nr_systemwide && list_empty(&filter->perf_events);
228 }
229 
230 static inline bool is_ret_probe(struct trace_uprobe *tu)
231 {
232         return tu->consumer.ret_handler != NULL;
233 }
234 
235 /*
236  * Allocate new trace_uprobe and initialize it (including uprobes).
237  */
238 static struct trace_uprobe *
239 alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
240 {
241         struct trace_uprobe *tu;
242 
243         if (!event || !is_good_name(event))
244                 return ERR_PTR(-EINVAL);
245 
246         if (!group || !is_good_name(group))
247                 return ERR_PTR(-EINVAL);
248 
249         tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL);
250         if (!tu)
251                 return ERR_PTR(-ENOMEM);
252 
253         tu->tp.call.class = &tu->tp.class;
254         tu->tp.call.name = kstrdup(event, GFP_KERNEL);
255         if (!tu->tp.call.name)
256                 goto error;
257 
258         tu->tp.class.system = kstrdup(group, GFP_KERNEL);
259         if (!tu->tp.class.system)
260                 goto error;
261 
262         INIT_LIST_HEAD(&tu->list);
263         INIT_LIST_HEAD(&tu->tp.files);
264         tu->consumer.handler = uprobe_dispatcher;
265         if (is_ret)
266                 tu->consumer.ret_handler = uretprobe_dispatcher;
267         init_trace_uprobe_filter(&tu->filter);
268         return tu;
269 
270 error:
271         kfree(tu->tp.call.name);
272         kfree(tu);
273 
274         return ERR_PTR(-ENOMEM);
275 }
276 
277 static void free_trace_uprobe(struct trace_uprobe *tu)
278 {
279         int i;
280 
281         for (i = 0; i < tu->tp.nr_args; i++)
282                 traceprobe_free_probe_arg(&tu->tp.args[i]);
283 
284         iput(tu->inode);
285         kfree(tu->tp.call.class->system);
286         kfree(tu->tp.call.name);
287         kfree(tu->filename);
288         kfree(tu);
289 }
290 
291 static struct trace_uprobe *find_probe_event(const char *event, const char *group)
292 {
293         struct trace_uprobe *tu;
294 
295         list_for_each_entry(tu, &uprobe_list, list)
296                 if (strcmp(trace_event_name(&tu->tp.call), event) == 0 &&
297                     strcmp(tu->tp.call.class->system, group) == 0)
298                         return tu;
299 
300         return NULL;
301 }
302 
303 /* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */
304 static int unregister_trace_uprobe(struct trace_uprobe *tu)
305 {
306         int ret;
307 
308         ret = unregister_uprobe_event(tu);
309         if (ret)
310                 return ret;
311 
312         list_del(&tu->list);
313         free_trace_uprobe(tu);
314         return 0;
315 }
316 
317 /* Register a trace_uprobe and probe_event */
318 static int register_trace_uprobe(struct trace_uprobe *tu)
319 {
320         struct trace_uprobe *old_tu;
321         int ret;
322 
323         mutex_lock(&uprobe_lock);
324 
325         /* register as an event */
326         old_tu = find_probe_event(trace_event_name(&tu->tp.call),
327                         tu->tp.call.class->system);
328         if (old_tu) {
329                 /* delete old event */
330                 ret = unregister_trace_uprobe(old_tu);
331                 if (ret)
332                         goto end;
333         }
334 
335         ret = register_uprobe_event(tu);
336         if (ret) {
337                 pr_warning("Failed to register probe event(%d)\n", ret);
338                 goto end;
339         }
340 
341         list_add_tail(&tu->list, &uprobe_list);
342 
343 end:
344         mutex_unlock(&uprobe_lock);
345 
346         return ret;
347 }
348 
349 /*
350  * Argument syntax:
351  *  - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS]
352  *
353  *  - Remove uprobe: -:[GRP/]EVENT
354  */
355 static int create_trace_uprobe(int argc, char **argv)
356 {
357         struct trace_uprobe *tu;
358         struct inode *inode;
359         char *arg, *event, *group, *filename;
360         char buf[MAX_EVENT_NAME_LEN];
361         struct path path;
362         unsigned long offset;
363         bool is_delete, is_return;
364         int i, ret;
365 
366         inode = NULL;
367         ret = 0;
368         is_delete = false;
369         is_return = false;
370         event = NULL;
371         group = NULL;
372 
373         /* argc must be >= 1 */
374         if (argv[0][0] == '-')
375                 is_delete = true;
376         else if (argv[0][0] == 'r')
377                 is_return = true;
378         else if (argv[0][0] != 'p') {
379                 pr_info("Probe definition must be started with 'p', 'r' or '-'.\n");
380                 return -EINVAL;
381         }
382 
383         if (argv[0][1] == ':') {
384                 event = &argv[0][2];
385                 arg = strchr(event, '/');
386 
387                 if (arg) {
388                         group = event;
389                         event = arg + 1;
390                         event[-1] = '\0';
391 
392                         if (strlen(group) == 0) {
393                                 pr_info("Group name is not specified\n");
394                                 return -EINVAL;
395                         }
396                 }
397                 if (strlen(event) == 0) {
398                         pr_info("Event name is not specified\n");
399                         return -EINVAL;
400                 }
401         }
402         if (!group)
403                 group = UPROBE_EVENT_SYSTEM;
404 
405         if (is_delete) {
406                 int ret;
407 
408                 if (!event) {
409                         pr_info("Delete command needs an event name.\n");
410                         return -EINVAL;
411                 }
412                 mutex_lock(&uprobe_lock);
413                 tu = find_probe_event(event, group);
414 
415                 if (!tu) {
416                         mutex_unlock(&uprobe_lock);
417                         pr_info("Event %s/%s doesn't exist.\n", group, event);
418                         return -ENOENT;
419                 }
420                 /* delete an event */
421                 ret = unregister_trace_uprobe(tu);
422                 mutex_unlock(&uprobe_lock);
423                 return ret;
424         }
425 
426         if (argc < 2) {
427                 pr_info("Probe point is not specified.\n");
428                 return -EINVAL;
429         }
430         if (isdigit(argv[1][0])) {
431                 pr_info("probe point must be have a filename.\n");
432                 return -EINVAL;
433         }
434         arg = strchr(argv[1], ':');
435         if (!arg) {
436                 ret = -EINVAL;
437                 goto fail_address_parse;
438         }
439 
440         *arg++ = '\0';
441         filename = argv[1];
442         ret = kern_path(filename, LOOKUP_FOLLOW, &path);
443         if (ret)
444                 goto fail_address_parse;
445 
446         inode = igrab(d_inode(path.dentry));
447         path_put(&path);
448 
449         if (!inode || !S_ISREG(inode->i_mode)) {
450                 ret = -EINVAL;
451                 goto fail_address_parse;
452         }
453 
454         ret = kstrtoul(arg, 0, &offset);
455         if (ret)
456                 goto fail_address_parse;
457 
458         argc -= 2;
459         argv += 2;
460 
461         /* setup a probe */
462         if (!event) {
463                 char *tail;
464                 char *ptr;
465 
466                 tail = kstrdup(kbasename(filename), GFP_KERNEL);
467                 if (!tail) {
468                         ret = -ENOMEM;
469                         goto fail_address_parse;
470                 }
471 
472                 ptr = strpbrk(tail, ".-_");
473                 if (ptr)
474                         *ptr = '\0';
475 
476                 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
477                 event = buf;
478                 kfree(tail);
479         }
480 
481         tu = alloc_trace_uprobe(group, event, argc, is_return);
482         if (IS_ERR(tu)) {
483                 pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu));
484                 ret = PTR_ERR(tu);
485                 goto fail_address_parse;
486         }
487         tu->offset = offset;
488         tu->inode = inode;
489         tu->filename = kstrdup(filename, GFP_KERNEL);
490 
491         if (!tu->filename) {
492                 pr_info("Failed to allocate filename.\n");
493                 ret = -ENOMEM;
494                 goto error;
495         }
496 
497         /* parse arguments */
498         ret = 0;
499         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
500                 struct probe_arg *parg = &tu->tp.args[i];
501 
502                 /* Increment count for freeing args in error case */
503                 tu->tp.nr_args++;
504 
505                 /* Parse argument name */
506                 arg = strchr(argv[i], '=');
507                 if (arg) {
508                         *arg++ = '\0';
509                         parg->name = kstrdup(argv[i], GFP_KERNEL);
510                 } else {
511                         arg = argv[i];
512                         /* If argument name is omitted, set "argN" */
513                         snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
514                         parg->name = kstrdup(buf, GFP_KERNEL);
515                 }
516 
517                 if (!parg->name) {
518                         pr_info("Failed to allocate argument[%d] name.\n", i);
519                         ret = -ENOMEM;
520                         goto error;
521                 }
522 
523                 if (!is_good_name(parg->name)) {
524                         pr_info("Invalid argument[%d] name: %s\n", i, parg->name);
525                         ret = -EINVAL;
526                         goto error;
527                 }
528 
529                 if (traceprobe_conflict_field_name(parg->name, tu->tp.args, i)) {
530                         pr_info("Argument[%d] name '%s' conflicts with "
531                                 "another field.\n", i, argv[i]);
532                         ret = -EINVAL;
533                         goto error;
534                 }
535 
536                 /* Parse fetch argument */
537                 ret = traceprobe_parse_probe_arg(arg, &tu->tp.size, parg,
538                                                  is_return, false,
539                                                  uprobes_fetch_type_table);
540                 if (ret) {
541                         pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
542                         goto error;
543                 }
544         }
545 
546         ret = register_trace_uprobe(tu);
547         if (ret)
548                 goto error;
549         return 0;
550 
551 error:
552         free_trace_uprobe(tu);
553         return ret;
554 
555 fail_address_parse:
556         iput(inode);
557 
558         pr_info("Failed to parse address or file.\n");
559 
560         return ret;
561 }
562 
563 static int cleanup_all_probes(void)
564 {
565         struct trace_uprobe *tu;
566         int ret = 0;
567 
568         mutex_lock(&uprobe_lock);
569         while (!list_empty(&uprobe_list)) {
570                 tu = list_entry(uprobe_list.next, struct trace_uprobe, list);
571                 ret = unregister_trace_uprobe(tu);
572                 if (ret)
573                         break;
574         }
575         mutex_unlock(&uprobe_lock);
576         return ret;
577 }
578 
579 /* Probes listing interfaces */
580 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
581 {
582         mutex_lock(&uprobe_lock);
583         return seq_list_start(&uprobe_list, *pos);
584 }
585 
586 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
587 {
588         return seq_list_next(v, &uprobe_list, pos);
589 }
590 
591 static void probes_seq_stop(struct seq_file *m, void *v)
592 {
593         mutex_unlock(&uprobe_lock);
594 }
595 
596 static int probes_seq_show(struct seq_file *m, void *v)
597 {
598         struct trace_uprobe *tu = v;
599         char c = is_ret_probe(tu) ? 'r' : 'p';
600         int i;
601 
602         seq_printf(m, "%c:%s/%s", c, tu->tp.call.class->system,
603                         trace_event_name(&tu->tp.call));
604         seq_printf(m, " %s:0x%p", tu->filename, (void *)tu->offset);
605 
606         for (i = 0; i < tu->tp.nr_args; i++)
607                 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm);
608 
609         seq_putc(m, '\n');
610         return 0;
611 }
612 
613 static const struct seq_operations probes_seq_op = {
614         .start  = probes_seq_start,
615         .next   = probes_seq_next,
616         .stop   = probes_seq_stop,
617         .show   = probes_seq_show
618 };
619 
620 static int probes_open(struct inode *inode, struct file *file)
621 {
622         int ret;
623 
624         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
625                 ret = cleanup_all_probes();
626                 if (ret)
627                         return ret;
628         }
629 
630         return seq_open(file, &probes_seq_op);
631 }
632 
633 static ssize_t probes_write(struct file *file, const char __user *buffer,
634                             size_t count, loff_t *ppos)
635 {
636         return traceprobe_probes_write(file, buffer, count, ppos, create_trace_uprobe);
637 }
638 
639 static const struct file_operations uprobe_events_ops = {
640         .owner          = THIS_MODULE,
641         .open           = probes_open,
642         .read           = seq_read,
643         .llseek         = seq_lseek,
644         .release        = seq_release,
645         .write          = probes_write,
646 };
647 
648 /* Probes profiling interfaces */
649 static int probes_profile_seq_show(struct seq_file *m, void *v)
650 {
651         struct trace_uprobe *tu = v;
652 
653         seq_printf(m, "  %s %-44s %15lu\n", tu->filename,
654                         trace_event_name(&tu->tp.call), tu->nhit);
655         return 0;
656 }
657 
658 static const struct seq_operations profile_seq_op = {
659         .start  = probes_seq_start,
660         .next   = probes_seq_next,
661         .stop   = probes_seq_stop,
662         .show   = probes_profile_seq_show
663 };
664 
665 static int profile_open(struct inode *inode, struct file *file)
666 {
667         return seq_open(file, &profile_seq_op);
668 }
669 
670 static const struct file_operations uprobe_profile_ops = {
671         .owner          = THIS_MODULE,
672         .open           = profile_open,
673         .read           = seq_read,
674         .llseek         = seq_lseek,
675         .release        = seq_release,
676 };
677 
678 struct uprobe_cpu_buffer {
679         struct mutex mutex;
680         void *buf;
681 };
682 static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer;
683 static int uprobe_buffer_refcnt;
684 
685 static int uprobe_buffer_init(void)
686 {
687         int cpu, err_cpu;
688 
689         uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer);
690         if (uprobe_cpu_buffer == NULL)
691                 return -ENOMEM;
692 
693         for_each_possible_cpu(cpu) {
694                 struct page *p = alloc_pages_node(cpu_to_node(cpu),
695                                                   GFP_KERNEL, 0);
696                 if (p == NULL) {
697                         err_cpu = cpu;
698                         goto err;
699                 }
700                 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p);
701                 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex);
702         }
703 
704         return 0;
705 
706 err:
707         for_each_possible_cpu(cpu) {
708                 if (cpu == err_cpu)
709                         break;
710                 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf);
711         }
712 
713         free_percpu(uprobe_cpu_buffer);
714         return -ENOMEM;
715 }
716 
717 static int uprobe_buffer_enable(void)
718 {
719         int ret = 0;
720 
721         BUG_ON(!mutex_is_locked(&event_mutex));
722 
723         if (uprobe_buffer_refcnt++ == 0) {
724                 ret = uprobe_buffer_init();
725                 if (ret < 0)
726                         uprobe_buffer_refcnt--;
727         }
728 
729         return ret;
730 }
731 
732 static void uprobe_buffer_disable(void)
733 {
734         int cpu;
735 
736         BUG_ON(!mutex_is_locked(&event_mutex));
737 
738         if (--uprobe_buffer_refcnt == 0) {
739                 for_each_possible_cpu(cpu)
740                         free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer,
741                                                              cpu)->buf);
742 
743                 free_percpu(uprobe_cpu_buffer);
744                 uprobe_cpu_buffer = NULL;
745         }
746 }
747 
748 static struct uprobe_cpu_buffer *uprobe_buffer_get(void)
749 {
750         struct uprobe_cpu_buffer *ucb;
751         int cpu;
752 
753         cpu = raw_smp_processor_id();
754         ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu);
755 
756         /*
757          * Use per-cpu buffers for fastest access, but we might migrate
758          * so the mutex makes sure we have sole access to it.
759          */
760         mutex_lock(&ucb->mutex);
761 
762         return ucb;
763 }
764 
765 static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb)
766 {
767         mutex_unlock(&ucb->mutex);
768 }
769 
770 static void __uprobe_trace_func(struct trace_uprobe *tu,
771                                 unsigned long func, struct pt_regs *regs,
772                                 struct uprobe_cpu_buffer *ucb, int dsize,
773                                 struct trace_event_file *trace_file)
774 {
775         struct uprobe_trace_entry_head *entry;
776         struct ring_buffer_event *event;
777         struct ring_buffer *buffer;
778         void *data;
779         int size, esize;
780         struct trace_event_call *call = &tu->tp.call;
781 
782         WARN_ON(call != trace_file->event_call);
783 
784         if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE))
785                 return;
786 
787         if (trace_trigger_soft_disabled(trace_file))
788                 return;
789 
790         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
791         size = esize + tu->tp.size + dsize;
792         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
793                                                 call->event.type, size, 0, 0);
794         if (!event)
795                 return;
796 
797         entry = ring_buffer_event_data(event);
798         if (is_ret_probe(tu)) {
799                 entry->vaddr[0] = func;
800                 entry->vaddr[1] = instruction_pointer(regs);
801                 data = DATAOF_TRACE_ENTRY(entry, true);
802         } else {
803                 entry->vaddr[0] = instruction_pointer(regs);
804                 data = DATAOF_TRACE_ENTRY(entry, false);
805         }
806 
807         memcpy(data, ucb->buf, tu->tp.size + dsize);
808 
809         event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0);
810 }
811 
812 /* uprobe handler */
813 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs,
814                              struct uprobe_cpu_buffer *ucb, int dsize)
815 {
816         struct event_file_link *link;
817 
818         if (is_ret_probe(tu))
819                 return 0;
820 
821         rcu_read_lock();
822         list_for_each_entry_rcu(link, &tu->tp.files, list)
823                 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file);
824         rcu_read_unlock();
825 
826         return 0;
827 }
828 
829 static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func,
830                                  struct pt_regs *regs,
831                                  struct uprobe_cpu_buffer *ucb, int dsize)
832 {
833         struct event_file_link *link;
834 
835         rcu_read_lock();
836         list_for_each_entry_rcu(link, &tu->tp.files, list)
837                 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file);
838         rcu_read_unlock();
839 }
840 
841 /* Event entry printers */
842 static enum print_line_t
843 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
844 {
845         struct uprobe_trace_entry_head *entry;
846         struct trace_seq *s = &iter->seq;
847         struct trace_uprobe *tu;
848         u8 *data;
849         int i;
850 
851         entry = (struct uprobe_trace_entry_head *)iter->ent;
852         tu = container_of(event, struct trace_uprobe, tp.call.event);
853 
854         if (is_ret_probe(tu)) {
855                 trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
856                                  trace_event_name(&tu->tp.call),
857                                  entry->vaddr[1], entry->vaddr[0]);
858                 data = DATAOF_TRACE_ENTRY(entry, true);
859         } else {
860                 trace_seq_printf(s, "%s: (0x%lx)",
861                                  trace_event_name(&tu->tp.call),
862                                  entry->vaddr[0]);
863                 data = DATAOF_TRACE_ENTRY(entry, false);
864         }
865 
866         for (i = 0; i < tu->tp.nr_args; i++) {
867                 struct probe_arg *parg = &tu->tp.args[i];
868 
869                 if (!parg->type->print(s, parg->name, data + parg->offset, entry))
870                         goto out;
871         }
872 
873         trace_seq_putc(s, '\n');
874 
875  out:
876         return trace_handle_return(s);
877 }
878 
879 typedef bool (*filter_func_t)(struct uprobe_consumer *self,
880                                 enum uprobe_filter_ctx ctx,
881                                 struct mm_struct *mm);
882 
883 static int
884 probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file,
885                    filter_func_t filter)
886 {
887         bool enabled = trace_probe_is_enabled(&tu->tp);
888         struct event_file_link *link = NULL;
889         int ret;
890 
891         if (file) {
892                 if (tu->tp.flags & TP_FLAG_PROFILE)
893                         return -EINTR;
894 
895                 link = kmalloc(sizeof(*link), GFP_KERNEL);
896                 if (!link)
897                         return -ENOMEM;
898 
899                 link->file = file;
900                 list_add_tail_rcu(&link->list, &tu->tp.files);
901 
902                 tu->tp.flags |= TP_FLAG_TRACE;
903         } else {
904                 if (tu->tp.flags & TP_FLAG_TRACE)
905                         return -EINTR;
906 
907                 tu->tp.flags |= TP_FLAG_PROFILE;
908         }
909 
910         WARN_ON(!uprobe_filter_is_empty(&tu->filter));
911 
912         if (enabled)
913                 return 0;
914 
915         ret = uprobe_buffer_enable();
916         if (ret)
917                 goto err_flags;
918 
919         tu->consumer.filter = filter;
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->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE;
966 
967         uprobe_buffer_disable();
968 }
969 
970 static int uprobe_event_define_fields(struct trace_event_call *event_call)
971 {
972         int ret, i, size;
973         struct uprobe_trace_entry_head field;
974         struct trace_uprobe *tu = event_call->data;
975 
976         if (is_ret_probe(tu)) {
977                 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0);
978                 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0);
979                 size = SIZEOF_TRACE_ENTRY(true);
980         } else {
981                 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0);
982                 size = SIZEOF_TRACE_ENTRY(false);
983         }
984         /* Set argument names as fields */
985         for (i = 0; i < tu->tp.nr_args; i++) {
986                 struct probe_arg *parg = &tu->tp.args[i];
987 
988                 ret = trace_define_field(event_call, parg->type->fmttype,
989                                          parg->name, size + parg->offset,
990                                          parg->type->size, parg->type->is_signed,
991                                          FILTER_OTHER);
992 
993                 if (ret)
994                         return ret;
995         }
996         return 0;
997 }
998 
999 #ifdef CONFIG_PERF_EVENTS
1000 static bool
1001 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
1002 {
1003         struct perf_event *event;
1004 
1005         if (filter->nr_systemwide)
1006                 return true;
1007 
1008         list_for_each_entry(event, &filter->perf_events, hw.tp_list) {
1009                 if (event->hw.target->mm == mm)
1010                         return true;
1011         }
1012 
1013         return false;
1014 }
1015 
1016 static inline bool
1017 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event)
1018 {
1019         return __uprobe_perf_filter(&tu->filter, event->hw.target->mm);
1020 }
1021 
1022 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event)
1023 {
1024         bool done;
1025 
1026         write_lock(&tu->filter.rwlock);
1027         if (event->hw.target) {
1028                 list_del(&event->hw.tp_list);
1029                 done = tu->filter.nr_systemwide ||
1030                         (event->hw.target->flags & PF_EXITING) ||
1031                         uprobe_filter_event(tu, event);
1032         } else {
1033                 tu->filter.nr_systemwide--;
1034                 done = tu->filter.nr_systemwide;
1035         }
1036         write_unlock(&tu->filter.rwlock);
1037 
1038         if (!done)
1039                 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
1040 
1041         return 0;
1042 }
1043 
1044 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
1045 {
1046         bool done;
1047         int err;
1048 
1049         write_lock(&tu->filter.rwlock);
1050         if (event->hw.target) {
1051                 /*
1052                  * event->parent != NULL means copy_process(), we can avoid
1053                  * uprobe_apply(). current->mm must be probed and we can rely
1054                  * on dup_mmap() which preserves the already installed bp's.
1055                  *
1056                  * attr.enable_on_exec means that exec/mmap will install the
1057                  * breakpoints we need.
1058                  */
1059                 done = tu->filter.nr_systemwide ||
1060                         event->parent || event->attr.enable_on_exec ||
1061                         uprobe_filter_event(tu, event);
1062                 list_add(&event->hw.tp_list, &tu->filter.perf_events);
1063         } else {
1064                 done = tu->filter.nr_systemwide;
1065                 tu->filter.nr_systemwide++;
1066         }
1067         write_unlock(&tu->filter.rwlock);
1068 
1069         err = 0;
1070         if (!done) {
1071                 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
1072                 if (err)
1073                         uprobe_perf_close(tu, event);
1074         }
1075         return err;
1076 }
1077 
1078 static bool uprobe_perf_filter(struct uprobe_consumer *uc,
1079                                 enum uprobe_filter_ctx ctx, struct mm_struct *mm)
1080 {
1081         struct trace_uprobe *tu;
1082         int ret;
1083 
1084         tu = container_of(uc, struct trace_uprobe, consumer);
1085         read_lock(&tu->filter.rwlock);
1086         ret = __uprobe_perf_filter(&tu->filter, mm);
1087         read_unlock(&tu->filter.rwlock);
1088 
1089         return ret;
1090 }
1091 
1092 static void __uprobe_perf_func(struct trace_uprobe *tu,
1093                                unsigned long func, struct pt_regs *regs,
1094                                struct uprobe_cpu_buffer *ucb, int dsize)
1095 {
1096         struct trace_event_call *call = &tu->tp.call;
1097         struct uprobe_trace_entry_head *entry;
1098         struct hlist_head *head;
1099         void *data;
1100         int size, esize;
1101         int rctx;
1102 
1103         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1104 
1105         size = esize + tu->tp.size + dsize;
1106         size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32);
1107         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
1108                 return;
1109 
1110         preempt_disable();
1111         head = this_cpu_ptr(call->perf_events);
1112         if (hlist_empty(head))
1113                 goto out;
1114 
1115         entry = perf_trace_buf_prepare(size, call->event.type, NULL, &rctx);
1116         if (!entry)
1117                 goto out;
1118 
1119         if (is_ret_probe(tu)) {
1120                 entry->vaddr[0] = func;
1121                 entry->vaddr[1] = instruction_pointer(regs);
1122                 data = DATAOF_TRACE_ENTRY(entry, true);
1123         } else {
1124                 entry->vaddr[0] = instruction_pointer(regs);
1125                 data = DATAOF_TRACE_ENTRY(entry, false);
1126         }
1127 
1128         memcpy(data, ucb->buf, tu->tp.size + dsize);
1129 
1130         if (size - esize > tu->tp.size + dsize) {
1131                 int len = tu->tp.size + dsize;
1132 
1133                 memset(data + len, 0, size - esize - len);
1134         }
1135 
1136         perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
1137  out:
1138         preempt_enable();
1139 }
1140 
1141 /* uprobe profile handler */
1142 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs,
1143                             struct uprobe_cpu_buffer *ucb, int dsize)
1144 {
1145         if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
1146                 return UPROBE_HANDLER_REMOVE;
1147 
1148         if (!is_ret_probe(tu))
1149                 __uprobe_perf_func(tu, 0, regs, ucb, dsize);
1150         return 0;
1151 }
1152 
1153 static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func,
1154                                 struct pt_regs *regs,
1155                                 struct uprobe_cpu_buffer *ucb, int dsize)
1156 {
1157         __uprobe_perf_func(tu, func, regs, ucb, dsize);
1158 }
1159 #endif  /* CONFIG_PERF_EVENTS */
1160 
1161 static int
1162 trace_uprobe_register(struct trace_event_call *event, enum trace_reg type,
1163                       void *data)
1164 {
1165         struct trace_uprobe *tu = event->data;
1166         struct trace_event_file *file = data;
1167 
1168         switch (type) {
1169         case TRACE_REG_REGISTER:
1170                 return probe_event_enable(tu, file, NULL);
1171 
1172         case TRACE_REG_UNREGISTER:
1173                 probe_event_disable(tu, file);
1174                 return 0;
1175 
1176 #ifdef CONFIG_PERF_EVENTS
1177         case TRACE_REG_PERF_REGISTER:
1178                 return probe_event_enable(tu, NULL, uprobe_perf_filter);
1179 
1180         case TRACE_REG_PERF_UNREGISTER:
1181                 probe_event_disable(tu, NULL);
1182                 return 0;
1183 
1184         case TRACE_REG_PERF_OPEN:
1185                 return uprobe_perf_open(tu, data);
1186 
1187         case TRACE_REG_PERF_CLOSE:
1188                 return uprobe_perf_close(tu, data);
1189 
1190 #endif
1191         default:
1192                 return 0;
1193         }
1194         return 0;
1195 }
1196 
1197 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
1198 {
1199         struct trace_uprobe *tu;
1200         struct uprobe_dispatch_data udd;
1201         struct uprobe_cpu_buffer *ucb;
1202         int dsize, esize;
1203         int ret = 0;
1204 
1205 
1206         tu = container_of(con, struct trace_uprobe, consumer);
1207         tu->nhit++;
1208 
1209         udd.tu = tu;
1210         udd.bp_addr = instruction_pointer(regs);
1211 
1212         current->utask->vaddr = (unsigned long) &udd;
1213 
1214         if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1215                 return 0;
1216 
1217         dsize = __get_data_size(&tu->tp, regs);
1218         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1219 
1220         ucb = uprobe_buffer_get();
1221         store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
1222 
1223         if (tu->tp.flags & TP_FLAG_TRACE)
1224                 ret |= uprobe_trace_func(tu, regs, ucb, dsize);
1225 
1226 #ifdef CONFIG_PERF_EVENTS
1227         if (tu->tp.flags & TP_FLAG_PROFILE)
1228                 ret |= uprobe_perf_func(tu, regs, ucb, dsize);
1229 #endif
1230         uprobe_buffer_put(ucb);
1231         return ret;
1232 }
1233 
1234 static int uretprobe_dispatcher(struct uprobe_consumer *con,
1235                                 unsigned long func, struct pt_regs *regs)
1236 {
1237         struct trace_uprobe *tu;
1238         struct uprobe_dispatch_data udd;
1239         struct uprobe_cpu_buffer *ucb;
1240         int dsize, esize;
1241 
1242         tu = container_of(con, struct trace_uprobe, consumer);
1243 
1244         udd.tu = tu;
1245         udd.bp_addr = func;
1246 
1247         current->utask->vaddr = (unsigned long) &udd;
1248 
1249         if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1250                 return 0;
1251 
1252         dsize = __get_data_size(&tu->tp, regs);
1253         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1254 
1255         ucb = uprobe_buffer_get();
1256         store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
1257 
1258         if (tu->tp.flags & TP_FLAG_TRACE)
1259                 uretprobe_trace_func(tu, func, regs, ucb, dsize);
1260 
1261 #ifdef CONFIG_PERF_EVENTS
1262         if (tu->tp.flags & TP_FLAG_PROFILE)
1263                 uretprobe_perf_func(tu, func, regs, ucb, dsize);
1264 #endif
1265         uprobe_buffer_put(ucb);
1266         return 0;
1267 }
1268 
1269 static struct trace_event_functions uprobe_funcs = {
1270         .trace          = print_uprobe_event
1271 };
1272 
1273 static int register_uprobe_event(struct trace_uprobe *tu)
1274 {
1275         struct trace_event_call *call = &tu->tp.call;
1276         int ret;
1277 
1278         /* Initialize trace_event_call */
1279         INIT_LIST_HEAD(&call->class->fields);
1280         call->event.funcs = &uprobe_funcs;
1281         call->class->define_fields = uprobe_event_define_fields;
1282 
1283         if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0)
1284                 return -ENOMEM;
1285 
1286         ret = register_trace_event(&call->event);
1287         if (!ret) {
1288                 kfree(call->print_fmt);
1289                 return -ENODEV;
1290         }
1291 
1292         call->class->reg = trace_uprobe_register;
1293         call->data = tu;
1294         ret = trace_add_event_call(call);
1295 
1296         if (ret) {
1297                 pr_info("Failed to register uprobe event: %s\n",
1298                         trace_event_name(call));
1299                 kfree(call->print_fmt);
1300                 unregister_trace_event(&call->event);
1301         }
1302 
1303         return ret;
1304 }
1305 
1306 static int unregister_uprobe_event(struct trace_uprobe *tu)
1307 {
1308         int ret;
1309 
1310         /* tu->event is unregistered in trace_remove_event_call() */
1311         ret = trace_remove_event_call(&tu->tp.call);
1312         if (ret)
1313                 return ret;
1314         kfree(tu->tp.call.print_fmt);
1315         tu->tp.call.print_fmt = NULL;
1316         return 0;
1317 }
1318 
1319 /* Make a trace interface for controling probe points */
1320 static __init int init_uprobe_trace(void)
1321 {
1322         struct dentry *d_tracer;
1323 
1324         d_tracer = tracing_init_dentry();
1325         if (IS_ERR(d_tracer))
1326                 return 0;
1327 
1328         trace_create_file("uprobe_events", 0644, d_tracer,
1329                                     NULL, &uprobe_events_ops);
1330         /* Profile interface */
1331         trace_create_file("uprobe_profile", 0444, d_tracer,
1332                                     NULL, &uprobe_profile_ops);
1333         return 0;
1334 }
1335 
1336 fs_initcall(init_uprobe_trace);
1337 

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