Merge tag 'trace-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt...
[muen/linux.git] / kernel / trace / trace_kprobe.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Kprobes-based tracing events
4  *
5  * Created by Masami Hiramatsu <mhiramat@redhat.com>
6  *
7  */
8 #define pr_fmt(fmt)     "trace_kprobe: " fmt
9
10 #include <linux/module.h>
11 #include <linux/uaccess.h>
12 #include <linux/rculist.h>
13 #include <linux/error-injection.h>
14
15 #include "trace_kprobe_selftest.h"
16 #include "trace_probe.h"
17
18 #define KPROBE_EVENT_SYSTEM "kprobes"
19 #define KRETPROBE_MAXACTIVE_MAX 4096
20
21 /**
22  * Kprobe event core functions
23  */
24 struct trace_kprobe {
25         struct list_head        list;
26         struct kretprobe        rp;     /* Use rp.kp for kprobe use */
27         unsigned long __percpu *nhit;
28         const char              *symbol;        /* symbol name */
29         struct trace_probe      tp;
30 };
31
32 #define SIZEOF_TRACE_KPROBE(n)                          \
33         (offsetof(struct trace_kprobe, tp.args) +       \
34         (sizeof(struct probe_arg) * (n)))
35
36 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
37 {
38         return tk->rp.handler != NULL;
39 }
40
41 static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
42 {
43         return tk->symbol ? tk->symbol : "unknown";
44 }
45
46 static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
47 {
48         return tk->rp.kp.offset;
49 }
50
51 static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
52 {
53         return !!(kprobe_gone(&tk->rp.kp));
54 }
55
56 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
57                                                  struct module *mod)
58 {
59         int len = strlen(mod->name);
60         const char *name = trace_kprobe_symbol(tk);
61         return strncmp(mod->name, name, len) == 0 && name[len] == ':';
62 }
63
64 static nokprobe_inline bool trace_kprobe_is_on_module(struct trace_kprobe *tk)
65 {
66         return !!strchr(trace_kprobe_symbol(tk), ':');
67 }
68
69 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
70 {
71         unsigned long nhit = 0;
72         int cpu;
73
74         for_each_possible_cpu(cpu)
75                 nhit += *per_cpu_ptr(tk->nhit, cpu);
76
77         return nhit;
78 }
79
80 /* Return 0 if it fails to find the symbol address */
81 static nokprobe_inline
82 unsigned long trace_kprobe_address(struct trace_kprobe *tk)
83 {
84         unsigned long addr;
85
86         if (tk->symbol) {
87                 addr = (unsigned long)
88                         kallsyms_lookup_name(trace_kprobe_symbol(tk));
89                 if (addr)
90                         addr += tk->rp.kp.offset;
91         } else {
92                 addr = (unsigned long)tk->rp.kp.addr;
93         }
94         return addr;
95 }
96
97 bool trace_kprobe_on_func_entry(struct trace_event_call *call)
98 {
99         struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
100
101         return kprobe_on_func_entry(tk->rp.kp.addr,
102                         tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
103                         tk->rp.kp.addr ? 0 : tk->rp.kp.offset);
104 }
105
106 bool trace_kprobe_error_injectable(struct trace_event_call *call)
107 {
108         struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
109
110         return within_error_injection_list(trace_kprobe_address(tk));
111 }
112
113 static int register_kprobe_event(struct trace_kprobe *tk);
114 static int unregister_kprobe_event(struct trace_kprobe *tk);
115
116 static DEFINE_MUTEX(probe_lock);
117 static LIST_HEAD(probe_list);
118
119 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
120 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
121                                 struct pt_regs *regs);
122
123 /* Memory fetching by symbol */
124 struct symbol_cache {
125         char            *symbol;
126         long            offset;
127         unsigned long   addr;
128 };
129
130 unsigned long update_symbol_cache(struct symbol_cache *sc)
131 {
132         sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
133
134         if (sc->addr)
135                 sc->addr += sc->offset;
136
137         return sc->addr;
138 }
139
140 void free_symbol_cache(struct symbol_cache *sc)
141 {
142         kfree(sc->symbol);
143         kfree(sc);
144 }
145
146 struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
147 {
148         struct symbol_cache *sc;
149
150         if (!sym || strlen(sym) == 0)
151                 return NULL;
152
153         sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
154         if (!sc)
155                 return NULL;
156
157         sc->symbol = kstrdup(sym, GFP_KERNEL);
158         if (!sc->symbol) {
159                 kfree(sc);
160                 return NULL;
161         }
162         sc->offset = offset;
163         update_symbol_cache(sc);
164
165         return sc;
166 }
167
168 /*
169  * Kprobes-specific fetch functions
170  */
171 #define DEFINE_FETCH_stack(type)                                        \
172 static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,          \
173                                           void *offset, void *dest)     \
174 {                                                                       \
175         *(type *)dest = (type)regs_get_kernel_stack_nth(regs,           \
176                                 (unsigned int)((unsigned long)offset)); \
177 }                                                                       \
178 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(stack, type));
179
180 DEFINE_BASIC_FETCH_FUNCS(stack)
181 /* No string on the stack entry */
182 #define fetch_stack_string      NULL
183 #define fetch_stack_string_size NULL
184
185 #define DEFINE_FETCH_memory(type)                                       \
186 static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,         \
187                                           void *addr, void *dest)       \
188 {                                                                       \
189         type retval;                                                    \
190         if (probe_kernel_address(addr, retval))                         \
191                 *(type *)dest = 0;                                      \
192         else                                                            \
193                 *(type *)dest = retval;                                 \
194 }                                                                       \
195 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, type));
196
197 DEFINE_BASIC_FETCH_FUNCS(memory)
198 /*
199  * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
200  * length and relative data location.
201  */
202 static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
203                                             void *addr, void *dest)
204 {
205         int maxlen = get_rloc_len(*(u32 *)dest);
206         u8 *dst = get_rloc_data(dest);
207         long ret;
208
209         if (!maxlen)
210                 return;
211
212         /*
213          * Try to get string again, since the string can be changed while
214          * probing.
215          */
216         ret = strncpy_from_unsafe(dst, addr, maxlen);
217
218         if (ret < 0) {  /* Failed to fetch string */
219                 dst[0] = '\0';
220                 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
221         } else {
222                 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
223         }
224 }
225 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string));
226
227 /* Return the length of string -- including null terminal byte */
228 static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
229                                                  void *addr, void *dest)
230 {
231         mm_segment_t old_fs;
232         int ret, len = 0;
233         u8 c;
234
235         old_fs = get_fs();
236         set_fs(KERNEL_DS);
237         pagefault_disable();
238
239         do {
240                 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
241                 len++;
242         } while (c && ret == 0 && len < MAX_STRING_SIZE);
243
244         pagefault_enable();
245         set_fs(old_fs);
246
247         if (ret < 0)    /* Failed to check the length */
248                 *(u32 *)dest = 0;
249         else
250                 *(u32 *)dest = len;
251 }
252 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string_size));
253
254 #define DEFINE_FETCH_symbol(type)                                       \
255 void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs, void *data, void *dest)\
256 {                                                                       \
257         struct symbol_cache *sc = data;                                 \
258         if (sc->addr)                                                   \
259                 fetch_memory_##type(regs, (void *)sc->addr, dest);      \
260         else                                                            \
261                 *(type *)dest = 0;                                      \
262 }                                                                       \
263 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(symbol, type));
264
265 DEFINE_BASIC_FETCH_FUNCS(symbol)
266 DEFINE_FETCH_symbol(string)
267 DEFINE_FETCH_symbol(string_size)
268
269 /* kprobes don't support file_offset fetch methods */
270 #define fetch_file_offset_u8            NULL
271 #define fetch_file_offset_u16           NULL
272 #define fetch_file_offset_u32           NULL
273 #define fetch_file_offset_u64           NULL
274 #define fetch_file_offset_string        NULL
275 #define fetch_file_offset_string_size   NULL
276
277 /* Fetch type information table */
278 static const struct fetch_type kprobes_fetch_type_table[] = {
279         /* Special types */
280         [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
281                                         sizeof(u32), 1, "__data_loc char[]"),
282         [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
283                                         string_size, sizeof(u32), 0, "u32"),
284         /* Basic types */
285         ASSIGN_FETCH_TYPE(u8,  u8,  0),
286         ASSIGN_FETCH_TYPE(u16, u16, 0),
287         ASSIGN_FETCH_TYPE(u32, u32, 0),
288         ASSIGN_FETCH_TYPE(u64, u64, 0),
289         ASSIGN_FETCH_TYPE(s8,  u8,  1),
290         ASSIGN_FETCH_TYPE(s16, u16, 1),
291         ASSIGN_FETCH_TYPE(s32, u32, 1),
292         ASSIGN_FETCH_TYPE(s64, u64, 1),
293         ASSIGN_FETCH_TYPE_ALIAS(x8,  u8,  u8,  0),
294         ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
295         ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
296         ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
297
298         ASSIGN_FETCH_TYPE_END
299 };
300
301 /*
302  * Allocate new trace_probe and initialize it (including kprobes).
303  */
304 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
305                                              const char *event,
306                                              void *addr,
307                                              const char *symbol,
308                                              unsigned long offs,
309                                              int maxactive,
310                                              int nargs, bool is_return)
311 {
312         struct trace_kprobe *tk;
313         int ret = -ENOMEM;
314
315         tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
316         if (!tk)
317                 return ERR_PTR(ret);
318
319         tk->nhit = alloc_percpu(unsigned long);
320         if (!tk->nhit)
321                 goto error;
322
323         if (symbol) {
324                 tk->symbol = kstrdup(symbol, GFP_KERNEL);
325                 if (!tk->symbol)
326                         goto error;
327                 tk->rp.kp.symbol_name = tk->symbol;
328                 tk->rp.kp.offset = offs;
329         } else
330                 tk->rp.kp.addr = addr;
331
332         if (is_return)
333                 tk->rp.handler = kretprobe_dispatcher;
334         else
335                 tk->rp.kp.pre_handler = kprobe_dispatcher;
336
337         tk->rp.maxactive = maxactive;
338
339         if (!event || !is_good_name(event)) {
340                 ret = -EINVAL;
341                 goto error;
342         }
343
344         tk->tp.call.class = &tk->tp.class;
345         tk->tp.call.name = kstrdup(event, GFP_KERNEL);
346         if (!tk->tp.call.name)
347                 goto error;
348
349         if (!group || !is_good_name(group)) {
350                 ret = -EINVAL;
351                 goto error;
352         }
353
354         tk->tp.class.system = kstrdup(group, GFP_KERNEL);
355         if (!tk->tp.class.system)
356                 goto error;
357
358         INIT_LIST_HEAD(&tk->list);
359         INIT_LIST_HEAD(&tk->tp.files);
360         return tk;
361 error:
362         kfree(tk->tp.call.name);
363         kfree(tk->symbol);
364         free_percpu(tk->nhit);
365         kfree(tk);
366         return ERR_PTR(ret);
367 }
368
369 static void free_trace_kprobe(struct trace_kprobe *tk)
370 {
371         int i;
372
373         for (i = 0; i < tk->tp.nr_args; i++)
374                 traceprobe_free_probe_arg(&tk->tp.args[i]);
375
376         kfree(tk->tp.call.class->system);
377         kfree(tk->tp.call.name);
378         kfree(tk->symbol);
379         free_percpu(tk->nhit);
380         kfree(tk);
381 }
382
383 static struct trace_kprobe *find_trace_kprobe(const char *event,
384                                               const char *group)
385 {
386         struct trace_kprobe *tk;
387
388         list_for_each_entry(tk, &probe_list, list)
389                 if (strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
390                     strcmp(tk->tp.call.class->system, group) == 0)
391                         return tk;
392         return NULL;
393 }
394
395 static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
396 {
397         int ret = 0;
398
399         if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
400                 if (trace_kprobe_is_return(tk))
401                         ret = enable_kretprobe(&tk->rp);
402                 else
403                         ret = enable_kprobe(&tk->rp.kp);
404         }
405
406         return ret;
407 }
408
409 /*
410  * Enable trace_probe
411  * if the file is NULL, enable "perf" handler, or enable "trace" handler.
412  */
413 static int
414 enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
415 {
416         struct event_file_link *link;
417         int ret = 0;
418
419         if (file) {
420                 link = kmalloc(sizeof(*link), GFP_KERNEL);
421                 if (!link) {
422                         ret = -ENOMEM;
423                         goto out;
424                 }
425
426                 link->file = file;
427                 list_add_tail_rcu(&link->list, &tk->tp.files);
428
429                 tk->tp.flags |= TP_FLAG_TRACE;
430                 ret = __enable_trace_kprobe(tk);
431                 if (ret) {
432                         list_del_rcu(&link->list);
433                         kfree(link);
434                         tk->tp.flags &= ~TP_FLAG_TRACE;
435                 }
436
437         } else {
438                 tk->tp.flags |= TP_FLAG_PROFILE;
439                 ret = __enable_trace_kprobe(tk);
440                 if (ret)
441                         tk->tp.flags &= ~TP_FLAG_PROFILE;
442         }
443  out:
444         return ret;
445 }
446
447 /*
448  * Disable trace_probe
449  * if the file is NULL, disable "perf" handler, or disable "trace" handler.
450  */
451 static int
452 disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
453 {
454         struct event_file_link *link = NULL;
455         int wait = 0;
456         int ret = 0;
457
458         if (file) {
459                 link = find_event_file_link(&tk->tp, file);
460                 if (!link) {
461                         ret = -EINVAL;
462                         goto out;
463                 }
464
465                 list_del_rcu(&link->list);
466                 wait = 1;
467                 if (!list_empty(&tk->tp.files))
468                         goto out;
469
470                 tk->tp.flags &= ~TP_FLAG_TRACE;
471         } else
472                 tk->tp.flags &= ~TP_FLAG_PROFILE;
473
474         if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) {
475                 if (trace_kprobe_is_return(tk))
476                         disable_kretprobe(&tk->rp);
477                 else
478                         disable_kprobe(&tk->rp.kp);
479                 wait = 1;
480         }
481
482         /*
483          * if tk is not added to any list, it must be a local trace_kprobe
484          * created with perf_event_open. We don't need to wait for these
485          * trace_kprobes
486          */
487         if (list_empty(&tk->list))
488                 wait = 0;
489  out:
490         if (wait) {
491                 /*
492                  * Synchronize with kprobe_trace_func/kretprobe_trace_func
493                  * to ensure disabled (all running handlers are finished).
494                  * This is not only for kfree(), but also the caller,
495                  * trace_remove_event_call() supposes it for releasing
496                  * event_call related objects, which will be accessed in
497                  * the kprobe_trace_func/kretprobe_trace_func.
498                  */
499                 synchronize_sched();
500                 kfree(link);    /* Ignored if link == NULL */
501         }
502
503         return ret;
504 }
505
506 #if defined(CONFIG_KPROBES_ON_FTRACE) && \
507         !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
508 static bool within_notrace_func(struct trace_kprobe *tk)
509 {
510         unsigned long offset, size, addr;
511
512         addr = trace_kprobe_address(tk);
513         if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))
514                 return false;
515
516         return !ftrace_location_range(addr - offset, addr - offset + size);
517 }
518 #else
519 #define within_notrace_func(tk) (false)
520 #endif
521
522 /* Internal register function - just handle k*probes and flags */
523 static int __register_trace_kprobe(struct trace_kprobe *tk)
524 {
525         int i, ret;
526
527         if (trace_probe_is_registered(&tk->tp))
528                 return -EINVAL;
529
530         if (within_notrace_func(tk)) {
531                 pr_warn("Could not probe notrace function %s\n",
532                         trace_kprobe_symbol(tk));
533                 return -EINVAL;
534         }
535
536         for (i = 0; i < tk->tp.nr_args; i++)
537                 traceprobe_update_arg(&tk->tp.args[i]);
538
539         /* Set/clear disabled flag according to tp->flag */
540         if (trace_probe_is_enabled(&tk->tp))
541                 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
542         else
543                 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
544
545         if (trace_kprobe_is_return(tk))
546                 ret = register_kretprobe(&tk->rp);
547         else
548                 ret = register_kprobe(&tk->rp.kp);
549
550         if (ret == 0)
551                 tk->tp.flags |= TP_FLAG_REGISTERED;
552         else {
553                 if (ret == -ENOENT && trace_kprobe_is_on_module(tk)) {
554                         pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
555                         ret = 0;
556                 } else if (ret == -EILSEQ) {
557                         pr_warn("Probing address(0x%p) is not an instruction boundary.\n",
558                                 tk->rp.kp.addr);
559                         ret = -EINVAL;
560                 }
561         }
562
563         return ret;
564 }
565
566 /* Internal unregister function - just handle k*probes and flags */
567 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
568 {
569         if (trace_probe_is_registered(&tk->tp)) {
570                 if (trace_kprobe_is_return(tk))
571                         unregister_kretprobe(&tk->rp);
572                 else
573                         unregister_kprobe(&tk->rp.kp);
574                 tk->tp.flags &= ~TP_FLAG_REGISTERED;
575                 /* Cleanup kprobe for reuse */
576                 if (tk->rp.kp.symbol_name)
577                         tk->rp.kp.addr = NULL;
578         }
579 }
580
581 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
582 static int unregister_trace_kprobe(struct trace_kprobe *tk)
583 {
584         /* Enabled event can not be unregistered */
585         if (trace_probe_is_enabled(&tk->tp))
586                 return -EBUSY;
587
588         /* Will fail if probe is being used by ftrace or perf */
589         if (unregister_kprobe_event(tk))
590                 return -EBUSY;
591
592         __unregister_trace_kprobe(tk);
593         list_del(&tk->list);
594
595         return 0;
596 }
597
598 /* Register a trace_probe and probe_event */
599 static int register_trace_kprobe(struct trace_kprobe *tk)
600 {
601         struct trace_kprobe *old_tk;
602         int ret;
603
604         mutex_lock(&probe_lock);
605
606         /* Delete old (same name) event if exist */
607         old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call),
608                         tk->tp.call.class->system);
609         if (old_tk) {
610                 ret = unregister_trace_kprobe(old_tk);
611                 if (ret < 0)
612                         goto end;
613                 free_trace_kprobe(old_tk);
614         }
615
616         /* Register new event */
617         ret = register_kprobe_event(tk);
618         if (ret) {
619                 pr_warn("Failed to register probe event(%d)\n", ret);
620                 goto end;
621         }
622
623         /* Register k*probe */
624         ret = __register_trace_kprobe(tk);
625         if (ret < 0)
626                 unregister_kprobe_event(tk);
627         else
628                 list_add_tail(&tk->list, &probe_list);
629
630 end:
631         mutex_unlock(&probe_lock);
632         return ret;
633 }
634
635 /* Module notifier call back, checking event on the module */
636 static int trace_kprobe_module_callback(struct notifier_block *nb,
637                                        unsigned long val, void *data)
638 {
639         struct module *mod = data;
640         struct trace_kprobe *tk;
641         int ret;
642
643         if (val != MODULE_STATE_COMING)
644                 return NOTIFY_DONE;
645
646         /* Update probes on coming module */
647         mutex_lock(&probe_lock);
648         list_for_each_entry(tk, &probe_list, list) {
649                 if (trace_kprobe_within_module(tk, mod)) {
650                         /* Don't need to check busy - this should have gone. */
651                         __unregister_trace_kprobe(tk);
652                         ret = __register_trace_kprobe(tk);
653                         if (ret)
654                                 pr_warn("Failed to re-register probe %s on %s: %d\n",
655                                         trace_event_name(&tk->tp.call),
656                                         mod->name, ret);
657                 }
658         }
659         mutex_unlock(&probe_lock);
660
661         return NOTIFY_DONE;
662 }
663
664 static struct notifier_block trace_kprobe_module_nb = {
665         .notifier_call = trace_kprobe_module_callback,
666         .priority = 1   /* Invoked after kprobe module callback */
667 };
668
669 /* Convert certain expected symbols into '_' when generating event names */
670 static inline void sanitize_event_name(char *name)
671 {
672         while (*name++ != '\0')
673                 if (*name == ':' || *name == '.')
674                         *name = '_';
675 }
676
677 static int create_trace_kprobe(int argc, char **argv)
678 {
679         /*
680          * Argument syntax:
681          *  - Add kprobe:
682          *      p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
683          *  - Add kretprobe:
684          *      r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
685          * Fetch args:
686          *  $retval     : fetch return value
687          *  $stack      : fetch stack address
688          *  $stackN     : fetch Nth of stack (N:0-)
689          *  $comm       : fetch current task comm
690          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
691          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
692          *  %REG        : fetch register REG
693          * Dereferencing memory fetch:
694          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
695          * Alias name of args:
696          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
697          * Type of args:
698          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
699          */
700         struct trace_kprobe *tk;
701         int i, ret = 0;
702         bool is_return = false, is_delete = false;
703         char *symbol = NULL, *event = NULL, *group = NULL;
704         int maxactive = 0;
705         char *arg;
706         long offset = 0;
707         void *addr = NULL;
708         char buf[MAX_EVENT_NAME_LEN];
709
710         /* argc must be >= 1 */
711         if (argv[0][0] == 'p')
712                 is_return = false;
713         else if (argv[0][0] == 'r')
714                 is_return = true;
715         else if (argv[0][0] == '-')
716                 is_delete = true;
717         else {
718                 pr_info("Probe definition must be started with 'p', 'r' or"
719                         " '-'.\n");
720                 return -EINVAL;
721         }
722
723         event = strchr(&argv[0][1], ':');
724         if (event) {
725                 event[0] = '\0';
726                 event++;
727         }
728         if (is_return && isdigit(argv[0][1])) {
729                 ret = kstrtouint(&argv[0][1], 0, &maxactive);
730                 if (ret) {
731                         pr_info("Failed to parse maxactive.\n");
732                         return ret;
733                 }
734                 /* kretprobes instances are iterated over via a list. The
735                  * maximum should stay reasonable.
736                  */
737                 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
738                         pr_info("Maxactive is too big (%d > %d).\n",
739                                 maxactive, KRETPROBE_MAXACTIVE_MAX);
740                         return -E2BIG;
741                 }
742         }
743
744         if (event) {
745                 if (strchr(event, '/')) {
746                         group = event;
747                         event = strchr(group, '/') + 1;
748                         event[-1] = '\0';
749                         if (strlen(group) == 0) {
750                                 pr_info("Group name is not specified\n");
751                                 return -EINVAL;
752                         }
753                 }
754                 if (strlen(event) == 0) {
755                         pr_info("Event name is not specified\n");
756                         return -EINVAL;
757                 }
758         }
759         if (!group)
760                 group = KPROBE_EVENT_SYSTEM;
761
762         if (is_delete) {
763                 if (!event) {
764                         pr_info("Delete command needs an event name.\n");
765                         return -EINVAL;
766                 }
767                 mutex_lock(&probe_lock);
768                 tk = find_trace_kprobe(event, group);
769                 if (!tk) {
770                         mutex_unlock(&probe_lock);
771                         pr_info("Event %s/%s doesn't exist.\n", group, event);
772                         return -ENOENT;
773                 }
774                 /* delete an event */
775                 ret = unregister_trace_kprobe(tk);
776                 if (ret == 0)
777                         free_trace_kprobe(tk);
778                 mutex_unlock(&probe_lock);
779                 return ret;
780         }
781
782         if (argc < 2) {
783                 pr_info("Probe point is not specified.\n");
784                 return -EINVAL;
785         }
786
787         /* try to parse an address. if that fails, try to read the
788          * input as a symbol. */
789         if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
790                 /* a symbol specified */
791                 symbol = argv[1];
792                 /* TODO: support .init module functions */
793                 ret = traceprobe_split_symbol_offset(symbol, &offset);
794                 if (ret || offset < 0 || offset > UINT_MAX) {
795                         pr_info("Failed to parse either an address or a symbol.\n");
796                         return ret;
797                 }
798                 if (offset && is_return &&
799                     !kprobe_on_func_entry(NULL, symbol, offset)) {
800                         pr_info("Given offset is not valid for return probe.\n");
801                         return -EINVAL;
802                 }
803         }
804         argc -= 2; argv += 2;
805
806         /* setup a probe */
807         if (!event) {
808                 /* Make a new event name */
809                 if (symbol)
810                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
811                                  is_return ? 'r' : 'p', symbol, offset);
812                 else
813                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
814                                  is_return ? 'r' : 'p', addr);
815                 sanitize_event_name(buf);
816                 event = buf;
817         }
818         tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
819                                argc, is_return);
820         if (IS_ERR(tk)) {
821                 pr_info("Failed to allocate trace_probe.(%d)\n",
822                         (int)PTR_ERR(tk));
823                 return PTR_ERR(tk);
824         }
825
826         /* parse arguments */
827         ret = 0;
828         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
829                 struct probe_arg *parg = &tk->tp.args[i];
830
831                 /* Increment count for freeing args in error case */
832                 tk->tp.nr_args++;
833
834                 /* Parse argument name */
835                 arg = strchr(argv[i], '=');
836                 if (arg) {
837                         *arg++ = '\0';
838                         parg->name = kstrdup(argv[i], GFP_KERNEL);
839                 } else {
840                         arg = argv[i];
841                         /* If argument name is omitted, set "argN" */
842                         snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
843                         parg->name = kstrdup(buf, GFP_KERNEL);
844                 }
845
846                 if (!parg->name) {
847                         pr_info("Failed to allocate argument[%d] name.\n", i);
848                         ret = -ENOMEM;
849                         goto error;
850                 }
851
852                 if (!is_good_name(parg->name)) {
853                         pr_info("Invalid argument[%d] name: %s\n",
854                                 i, parg->name);
855                         ret = -EINVAL;
856                         goto error;
857                 }
858
859                 if (traceprobe_conflict_field_name(parg->name,
860                                                         tk->tp.args, i)) {
861                         pr_info("Argument[%d] name '%s' conflicts with "
862                                 "another field.\n", i, argv[i]);
863                         ret = -EINVAL;
864                         goto error;
865                 }
866
867                 /* Parse fetch argument */
868                 ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
869                                                 is_return, true,
870                                                 kprobes_fetch_type_table);
871                 if (ret) {
872                         pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
873                         goto error;
874                 }
875         }
876
877         ret = register_trace_kprobe(tk);
878         if (ret)
879                 goto error;
880         return 0;
881
882 error:
883         free_trace_kprobe(tk);
884         return ret;
885 }
886
887 static int release_all_trace_kprobes(void)
888 {
889         struct trace_kprobe *tk;
890         int ret = 0;
891
892         mutex_lock(&probe_lock);
893         /* Ensure no probe is in use. */
894         list_for_each_entry(tk, &probe_list, list)
895                 if (trace_probe_is_enabled(&tk->tp)) {
896                         ret = -EBUSY;
897                         goto end;
898                 }
899         /* TODO: Use batch unregistration */
900         while (!list_empty(&probe_list)) {
901                 tk = list_entry(probe_list.next, struct trace_kprobe, list);
902                 ret = unregister_trace_kprobe(tk);
903                 if (ret)
904                         goto end;
905                 free_trace_kprobe(tk);
906         }
907
908 end:
909         mutex_unlock(&probe_lock);
910
911         return ret;
912 }
913
914 /* Probes listing interfaces */
915 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
916 {
917         mutex_lock(&probe_lock);
918         return seq_list_start(&probe_list, *pos);
919 }
920
921 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
922 {
923         return seq_list_next(v, &probe_list, pos);
924 }
925
926 static void probes_seq_stop(struct seq_file *m, void *v)
927 {
928         mutex_unlock(&probe_lock);
929 }
930
931 static int probes_seq_show(struct seq_file *m, void *v)
932 {
933         struct trace_kprobe *tk = v;
934         int i;
935
936         seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
937         seq_printf(m, ":%s/%s", tk->tp.call.class->system,
938                         trace_event_name(&tk->tp.call));
939
940         if (!tk->symbol)
941                 seq_printf(m, " 0x%p", tk->rp.kp.addr);
942         else if (tk->rp.kp.offset)
943                 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
944                            tk->rp.kp.offset);
945         else
946                 seq_printf(m, " %s", trace_kprobe_symbol(tk));
947
948         for (i = 0; i < tk->tp.nr_args; i++)
949                 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
950         seq_putc(m, '\n');
951
952         return 0;
953 }
954
955 static const struct seq_operations probes_seq_op = {
956         .start  = probes_seq_start,
957         .next   = probes_seq_next,
958         .stop   = probes_seq_stop,
959         .show   = probes_seq_show
960 };
961
962 static int probes_open(struct inode *inode, struct file *file)
963 {
964         int ret;
965
966         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
967                 ret = release_all_trace_kprobes();
968                 if (ret < 0)
969                         return ret;
970         }
971
972         return seq_open(file, &probes_seq_op);
973 }
974
975 static ssize_t probes_write(struct file *file, const char __user *buffer,
976                             size_t count, loff_t *ppos)
977 {
978         return trace_parse_run_command(file, buffer, count, ppos,
979                                        create_trace_kprobe);
980 }
981
982 static const struct file_operations kprobe_events_ops = {
983         .owner          = THIS_MODULE,
984         .open           = probes_open,
985         .read           = seq_read,
986         .llseek         = seq_lseek,
987         .release        = seq_release,
988         .write          = probes_write,
989 };
990
991 /* Probes profiling interfaces */
992 static int probes_profile_seq_show(struct seq_file *m, void *v)
993 {
994         struct trace_kprobe *tk = v;
995
996         seq_printf(m, "  %-44s %15lu %15lu\n",
997                    trace_event_name(&tk->tp.call),
998                    trace_kprobe_nhit(tk),
999                    tk->rp.kp.nmissed);
1000
1001         return 0;
1002 }
1003
1004 static const struct seq_operations profile_seq_op = {
1005         .start  = probes_seq_start,
1006         .next   = probes_seq_next,
1007         .stop   = probes_seq_stop,
1008         .show   = probes_profile_seq_show
1009 };
1010
1011 static int profile_open(struct inode *inode, struct file *file)
1012 {
1013         return seq_open(file, &profile_seq_op);
1014 }
1015
1016 static const struct file_operations kprobe_profile_ops = {
1017         .owner          = THIS_MODULE,
1018         .open           = profile_open,
1019         .read           = seq_read,
1020         .llseek         = seq_lseek,
1021         .release        = seq_release,
1022 };
1023
1024 /* Kprobe handler */
1025 static nokprobe_inline void
1026 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
1027                     struct trace_event_file *trace_file)
1028 {
1029         struct kprobe_trace_entry_head *entry;
1030         struct ring_buffer_event *event;
1031         struct ring_buffer *buffer;
1032         int size, dsize, pc;
1033         unsigned long irq_flags;
1034         struct trace_event_call *call = &tk->tp.call;
1035
1036         WARN_ON(call != trace_file->event_call);
1037
1038         if (trace_trigger_soft_disabled(trace_file))
1039                 return;
1040
1041         local_save_flags(irq_flags);
1042         pc = preempt_count();
1043
1044         dsize = __get_data_size(&tk->tp, regs);
1045         size = sizeof(*entry) + tk->tp.size + dsize;
1046
1047         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1048                                                 call->event.type,
1049                                                 size, irq_flags, pc);
1050         if (!event)
1051                 return;
1052
1053         entry = ring_buffer_event_data(event);
1054         entry->ip = (unsigned long)tk->rp.kp.addr;
1055         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1056
1057         event_trigger_unlock_commit_regs(trace_file, buffer, event,
1058                                          entry, irq_flags, pc, regs);
1059 }
1060
1061 static void
1062 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1063 {
1064         struct event_file_link *link;
1065
1066         list_for_each_entry_rcu(link, &tk->tp.files, list)
1067                 __kprobe_trace_func(tk, regs, link->file);
1068 }
1069 NOKPROBE_SYMBOL(kprobe_trace_func);
1070
1071 /* Kretprobe handler */
1072 static nokprobe_inline void
1073 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1074                        struct pt_regs *regs,
1075                        struct trace_event_file *trace_file)
1076 {
1077         struct kretprobe_trace_entry_head *entry;
1078         struct ring_buffer_event *event;
1079         struct ring_buffer *buffer;
1080         int size, pc, dsize;
1081         unsigned long irq_flags;
1082         struct trace_event_call *call = &tk->tp.call;
1083
1084         WARN_ON(call != trace_file->event_call);
1085
1086         if (trace_trigger_soft_disabled(trace_file))
1087                 return;
1088
1089         local_save_flags(irq_flags);
1090         pc = preempt_count();
1091
1092         dsize = __get_data_size(&tk->tp, regs);
1093         size = sizeof(*entry) + tk->tp.size + dsize;
1094
1095         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1096                                                 call->event.type,
1097                                                 size, irq_flags, pc);
1098         if (!event)
1099                 return;
1100
1101         entry = ring_buffer_event_data(event);
1102         entry->func = (unsigned long)tk->rp.kp.addr;
1103         entry->ret_ip = (unsigned long)ri->ret_addr;
1104         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1105
1106         event_trigger_unlock_commit_regs(trace_file, buffer, event,
1107                                          entry, irq_flags, pc, regs);
1108 }
1109
1110 static void
1111 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1112                      struct pt_regs *regs)
1113 {
1114         struct event_file_link *link;
1115
1116         list_for_each_entry_rcu(link, &tk->tp.files, list)
1117                 __kretprobe_trace_func(tk, ri, regs, link->file);
1118 }
1119 NOKPROBE_SYMBOL(kretprobe_trace_func);
1120
1121 /* Event entry printers */
1122 static enum print_line_t
1123 print_kprobe_event(struct trace_iterator *iter, int flags,
1124                    struct trace_event *event)
1125 {
1126         struct kprobe_trace_entry_head *field;
1127         struct trace_seq *s = &iter->seq;
1128         struct trace_probe *tp;
1129         u8 *data;
1130         int i;
1131
1132         field = (struct kprobe_trace_entry_head *)iter->ent;
1133         tp = container_of(event, struct trace_probe, call.event);
1134
1135         trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1136
1137         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1138                 goto out;
1139
1140         trace_seq_putc(s, ')');
1141
1142         data = (u8 *)&field[1];
1143         for (i = 0; i < tp->nr_args; i++)
1144                 if (!tp->args[i].type->print(s, tp->args[i].name,
1145                                              data + tp->args[i].offset, field))
1146                         goto out;
1147
1148         trace_seq_putc(s, '\n');
1149  out:
1150         return trace_handle_return(s);
1151 }
1152
1153 static enum print_line_t
1154 print_kretprobe_event(struct trace_iterator *iter, int flags,
1155                       struct trace_event *event)
1156 {
1157         struct kretprobe_trace_entry_head *field;
1158         struct trace_seq *s = &iter->seq;
1159         struct trace_probe *tp;
1160         u8 *data;
1161         int i;
1162
1163         field = (struct kretprobe_trace_entry_head *)iter->ent;
1164         tp = container_of(event, struct trace_probe, call.event);
1165
1166         trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1167
1168         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1169                 goto out;
1170
1171         trace_seq_puts(s, " <- ");
1172
1173         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1174                 goto out;
1175
1176         trace_seq_putc(s, ')');
1177
1178         data = (u8 *)&field[1];
1179         for (i = 0; i < tp->nr_args; i++)
1180                 if (!tp->args[i].type->print(s, tp->args[i].name,
1181                                              data + tp->args[i].offset, field))
1182                         goto out;
1183
1184         trace_seq_putc(s, '\n');
1185
1186  out:
1187         return trace_handle_return(s);
1188 }
1189
1190
1191 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1192 {
1193         int ret, i;
1194         struct kprobe_trace_entry_head field;
1195         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1196
1197         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1198         /* Set argument names as fields */
1199         for (i = 0; i < tk->tp.nr_args; i++) {
1200                 struct probe_arg *parg = &tk->tp.args[i];
1201
1202                 ret = trace_define_field(event_call, parg->type->fmttype,
1203                                          parg->name,
1204                                          sizeof(field) + parg->offset,
1205                                          parg->type->size,
1206                                          parg->type->is_signed,
1207                                          FILTER_OTHER);
1208                 if (ret)
1209                         return ret;
1210         }
1211         return 0;
1212 }
1213
1214 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1215 {
1216         int ret, i;
1217         struct kretprobe_trace_entry_head field;
1218         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1219
1220         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1221         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1222         /* Set argument names as fields */
1223         for (i = 0; i < tk->tp.nr_args; i++) {
1224                 struct probe_arg *parg = &tk->tp.args[i];
1225
1226                 ret = trace_define_field(event_call, parg->type->fmttype,
1227                                          parg->name,
1228                                          sizeof(field) + parg->offset,
1229                                          parg->type->size,
1230                                          parg->type->is_signed,
1231                                          FILTER_OTHER);
1232                 if (ret)
1233                         return ret;
1234         }
1235         return 0;
1236 }
1237
1238 #ifdef CONFIG_PERF_EVENTS
1239
1240 /* Kprobe profile handler */
1241 static int
1242 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1243 {
1244         struct trace_event_call *call = &tk->tp.call;
1245         struct kprobe_trace_entry_head *entry;
1246         struct hlist_head *head;
1247         int size, __size, dsize;
1248         int rctx;
1249
1250         if (bpf_prog_array_valid(call)) {
1251                 unsigned long orig_ip = instruction_pointer(regs);
1252                 int ret;
1253
1254                 ret = trace_call_bpf(call, regs);
1255
1256                 /*
1257                  * We need to check and see if we modified the pc of the
1258                  * pt_regs, and if so return 1 so that we don't do the
1259                  * single stepping.
1260                  */
1261                 if (orig_ip != instruction_pointer(regs))
1262                         return 1;
1263                 if (!ret)
1264                         return 0;
1265         }
1266
1267         head = this_cpu_ptr(call->perf_events);
1268         if (hlist_empty(head))
1269                 return 0;
1270
1271         dsize = __get_data_size(&tk->tp, regs);
1272         __size = sizeof(*entry) + tk->tp.size + dsize;
1273         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1274         size -= sizeof(u32);
1275
1276         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1277         if (!entry)
1278                 return 0;
1279
1280         entry->ip = (unsigned long)tk->rp.kp.addr;
1281         memset(&entry[1], 0, dsize);
1282         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1283         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1284                               head, NULL);
1285         return 0;
1286 }
1287 NOKPROBE_SYMBOL(kprobe_perf_func);
1288
1289 /* Kretprobe profile handler */
1290 static void
1291 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1292                     struct pt_regs *regs)
1293 {
1294         struct trace_event_call *call = &tk->tp.call;
1295         struct kretprobe_trace_entry_head *entry;
1296         struct hlist_head *head;
1297         int size, __size, dsize;
1298         int rctx;
1299
1300         if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1301                 return;
1302
1303         head = this_cpu_ptr(call->perf_events);
1304         if (hlist_empty(head))
1305                 return;
1306
1307         dsize = __get_data_size(&tk->tp, regs);
1308         __size = sizeof(*entry) + tk->tp.size + dsize;
1309         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1310         size -= sizeof(u32);
1311
1312         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1313         if (!entry)
1314                 return;
1315
1316         entry->func = (unsigned long)tk->rp.kp.addr;
1317         entry->ret_ip = (unsigned long)ri->ret_addr;
1318         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1319         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1320                               head, NULL);
1321 }
1322 NOKPROBE_SYMBOL(kretprobe_perf_func);
1323
1324 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1325                         const char **symbol, u64 *probe_offset,
1326                         u64 *probe_addr, bool perf_type_tracepoint)
1327 {
1328         const char *pevent = trace_event_name(event->tp_event);
1329         const char *group = event->tp_event->class->system;
1330         struct trace_kprobe *tk;
1331
1332         if (perf_type_tracepoint)
1333                 tk = find_trace_kprobe(pevent, group);
1334         else
1335                 tk = event->tp_event->data;
1336         if (!tk)
1337                 return -EINVAL;
1338
1339         *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1340                                               : BPF_FD_TYPE_KPROBE;
1341         if (tk->symbol) {
1342                 *symbol = tk->symbol;
1343                 *probe_offset = tk->rp.kp.offset;
1344                 *probe_addr = 0;
1345         } else {
1346                 *symbol = NULL;
1347                 *probe_offset = 0;
1348                 *probe_addr = (unsigned long)tk->rp.kp.addr;
1349         }
1350         return 0;
1351 }
1352 #endif  /* CONFIG_PERF_EVENTS */
1353
1354 /*
1355  * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1356  *
1357  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1358  * lockless, but we can't race with this __init function.
1359  */
1360 static int kprobe_register(struct trace_event_call *event,
1361                            enum trace_reg type, void *data)
1362 {
1363         struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1364         struct trace_event_file *file = data;
1365
1366         switch (type) {
1367         case TRACE_REG_REGISTER:
1368                 return enable_trace_kprobe(tk, file);
1369         case TRACE_REG_UNREGISTER:
1370                 return disable_trace_kprobe(tk, file);
1371
1372 #ifdef CONFIG_PERF_EVENTS
1373         case TRACE_REG_PERF_REGISTER:
1374                 return enable_trace_kprobe(tk, NULL);
1375         case TRACE_REG_PERF_UNREGISTER:
1376                 return disable_trace_kprobe(tk, NULL);
1377         case TRACE_REG_PERF_OPEN:
1378         case TRACE_REG_PERF_CLOSE:
1379         case TRACE_REG_PERF_ADD:
1380         case TRACE_REG_PERF_DEL:
1381                 return 0;
1382 #endif
1383         }
1384         return 0;
1385 }
1386
1387 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1388 {
1389         struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1390         int ret = 0;
1391
1392         raw_cpu_inc(*tk->nhit);
1393
1394         if (tk->tp.flags & TP_FLAG_TRACE)
1395                 kprobe_trace_func(tk, regs);
1396 #ifdef CONFIG_PERF_EVENTS
1397         if (tk->tp.flags & TP_FLAG_PROFILE)
1398                 ret = kprobe_perf_func(tk, regs);
1399 #endif
1400         return ret;
1401 }
1402 NOKPROBE_SYMBOL(kprobe_dispatcher);
1403
1404 static int
1405 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1406 {
1407         struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1408
1409         raw_cpu_inc(*tk->nhit);
1410
1411         if (tk->tp.flags & TP_FLAG_TRACE)
1412                 kretprobe_trace_func(tk, ri, regs);
1413 #ifdef CONFIG_PERF_EVENTS
1414         if (tk->tp.flags & TP_FLAG_PROFILE)
1415                 kretprobe_perf_func(tk, ri, regs);
1416 #endif
1417         return 0;       /* We don't tweek kernel, so just return 0 */
1418 }
1419 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1420
1421 static struct trace_event_functions kretprobe_funcs = {
1422         .trace          = print_kretprobe_event
1423 };
1424
1425 static struct trace_event_functions kprobe_funcs = {
1426         .trace          = print_kprobe_event
1427 };
1428
1429 static inline void init_trace_event_call(struct trace_kprobe *tk,
1430                                          struct trace_event_call *call)
1431 {
1432         INIT_LIST_HEAD(&call->class->fields);
1433         if (trace_kprobe_is_return(tk)) {
1434                 call->event.funcs = &kretprobe_funcs;
1435                 call->class->define_fields = kretprobe_event_define_fields;
1436         } else {
1437                 call->event.funcs = &kprobe_funcs;
1438                 call->class->define_fields = kprobe_event_define_fields;
1439         }
1440
1441         call->flags = TRACE_EVENT_FL_KPROBE;
1442         call->class->reg = kprobe_register;
1443         call->data = tk;
1444 }
1445
1446 static int register_kprobe_event(struct trace_kprobe *tk)
1447 {
1448         struct trace_event_call *call = &tk->tp.call;
1449         int ret = 0;
1450
1451         init_trace_event_call(tk, call);
1452
1453         if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1454                 return -ENOMEM;
1455         ret = register_trace_event(&call->event);
1456         if (!ret) {
1457                 kfree(call->print_fmt);
1458                 return -ENODEV;
1459         }
1460         ret = trace_add_event_call(call);
1461         if (ret) {
1462                 pr_info("Failed to register kprobe event: %s\n",
1463                         trace_event_name(call));
1464                 kfree(call->print_fmt);
1465                 unregister_trace_event(&call->event);
1466         }
1467         return ret;
1468 }
1469
1470 static int unregister_kprobe_event(struct trace_kprobe *tk)
1471 {
1472         int ret;
1473
1474         /* tp->event is unregistered in trace_remove_event_call() */
1475         ret = trace_remove_event_call(&tk->tp.call);
1476         if (!ret)
1477                 kfree(tk->tp.call.print_fmt);
1478         return ret;
1479 }
1480
1481 #ifdef CONFIG_PERF_EVENTS
1482 /* create a trace_kprobe, but don't add it to global lists */
1483 struct trace_event_call *
1484 create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1485                           bool is_return)
1486 {
1487         struct trace_kprobe *tk;
1488         int ret;
1489         char *event;
1490
1491         /*
1492          * local trace_kprobes are not added to probe_list, so they are never
1493          * searched in find_trace_kprobe(). Therefore, there is no concern of
1494          * duplicated name here.
1495          */
1496         event = func ? func : "DUMMY_EVENT";
1497
1498         tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1499                                 offs, 0 /* maxactive */, 0 /* nargs */,
1500                                 is_return);
1501
1502         if (IS_ERR(tk)) {
1503                 pr_info("Failed to allocate trace_probe.(%d)\n",
1504                         (int)PTR_ERR(tk));
1505                 return ERR_CAST(tk);
1506         }
1507
1508         init_trace_event_call(tk, &tk->tp.call);
1509
1510         if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) {
1511                 ret = -ENOMEM;
1512                 goto error;
1513         }
1514
1515         ret = __register_trace_kprobe(tk);
1516         if (ret < 0) {
1517                 kfree(tk->tp.call.print_fmt);
1518                 goto error;
1519         }
1520
1521         return &tk->tp.call;
1522 error:
1523         free_trace_kprobe(tk);
1524         return ERR_PTR(ret);
1525 }
1526
1527 void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1528 {
1529         struct trace_kprobe *tk;
1530
1531         tk = container_of(event_call, struct trace_kprobe, tp.call);
1532
1533         if (trace_probe_is_enabled(&tk->tp)) {
1534                 WARN_ON(1);
1535                 return;
1536         }
1537
1538         __unregister_trace_kprobe(tk);
1539
1540         kfree(tk->tp.call.print_fmt);
1541         free_trace_kprobe(tk);
1542 }
1543 #endif /* CONFIG_PERF_EVENTS */
1544
1545 /* Make a tracefs interface for controlling probe points */
1546 static __init int init_kprobe_trace(void)
1547 {
1548         struct dentry *d_tracer;
1549         struct dentry *entry;
1550
1551         if (register_module_notifier(&trace_kprobe_module_nb))
1552                 return -EINVAL;
1553
1554         d_tracer = tracing_init_dentry();
1555         if (IS_ERR(d_tracer))
1556                 return 0;
1557
1558         entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1559                                     NULL, &kprobe_events_ops);
1560
1561         /* Event list interface */
1562         if (!entry)
1563                 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1564
1565         /* Profile interface */
1566         entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1567                                     NULL, &kprobe_profile_ops);
1568
1569         if (!entry)
1570                 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1571         return 0;
1572 }
1573 fs_initcall(init_kprobe_trace);
1574
1575
1576 #ifdef CONFIG_FTRACE_STARTUP_TEST
1577 static __init struct trace_event_file *
1578 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1579 {
1580         struct trace_event_file *file;
1581
1582         list_for_each_entry(file, &tr->events, list)
1583                 if (file->event_call == &tk->tp.call)
1584                         return file;
1585
1586         return NULL;
1587 }
1588
1589 /*
1590  * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1591  * stage, we can do this lockless.
1592  */
1593 static __init int kprobe_trace_self_tests_init(void)
1594 {
1595         int ret, warn = 0;
1596         int (*target)(int, int, int, int, int, int);
1597         struct trace_kprobe *tk;
1598         struct trace_event_file *file;
1599
1600         if (tracing_is_disabled())
1601                 return -ENODEV;
1602
1603         target = kprobe_trace_selftest_target;
1604
1605         pr_info("Testing kprobe tracing: ");
1606
1607         ret = trace_run_command("p:testprobe kprobe_trace_selftest_target "
1608                                 "$stack $stack0 +0($stack)",
1609                                 create_trace_kprobe);
1610         if (WARN_ON_ONCE(ret)) {
1611                 pr_warn("error on probing function entry.\n");
1612                 warn++;
1613         } else {
1614                 /* Enable trace point */
1615                 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1616                 if (WARN_ON_ONCE(tk == NULL)) {
1617                         pr_warn("error on getting new probe.\n");
1618                         warn++;
1619                 } else {
1620                         file = find_trace_probe_file(tk, top_trace_array());
1621                         if (WARN_ON_ONCE(file == NULL)) {
1622                                 pr_warn("error on getting probe file.\n");
1623                                 warn++;
1624                         } else
1625                                 enable_trace_kprobe(tk, file);
1626                 }
1627         }
1628
1629         ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target "
1630                                 "$retval", create_trace_kprobe);
1631         if (WARN_ON_ONCE(ret)) {
1632                 pr_warn("error on probing function return.\n");
1633                 warn++;
1634         } else {
1635                 /* Enable trace point */
1636                 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1637                 if (WARN_ON_ONCE(tk == NULL)) {
1638                         pr_warn("error on getting 2nd new probe.\n");
1639                         warn++;
1640                 } else {
1641                         file = find_trace_probe_file(tk, top_trace_array());
1642                         if (WARN_ON_ONCE(file == NULL)) {
1643                                 pr_warn("error on getting probe file.\n");
1644                                 warn++;
1645                         } else
1646                                 enable_trace_kprobe(tk, file);
1647                 }
1648         }
1649
1650         if (warn)
1651                 goto end;
1652
1653         ret = target(1, 2, 3, 4, 5, 6);
1654
1655         /*
1656          * Not expecting an error here, the check is only to prevent the
1657          * optimizer from removing the call to target() as otherwise there
1658          * are no side-effects and the call is never performed.
1659          */
1660         if (ret != 21)
1661                 warn++;
1662
1663         /* Disable trace points before removing it */
1664         tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1665         if (WARN_ON_ONCE(tk == NULL)) {
1666                 pr_warn("error on getting test probe.\n");
1667                 warn++;
1668         } else {
1669                 if (trace_kprobe_nhit(tk) != 1) {
1670                         pr_warn("incorrect number of testprobe hits\n");
1671                         warn++;
1672                 }
1673
1674                 file = find_trace_probe_file(tk, top_trace_array());
1675                 if (WARN_ON_ONCE(file == NULL)) {
1676                         pr_warn("error on getting probe file.\n");
1677                         warn++;
1678                 } else
1679                         disable_trace_kprobe(tk, file);
1680         }
1681
1682         tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1683         if (WARN_ON_ONCE(tk == NULL)) {
1684                 pr_warn("error on getting 2nd test probe.\n");
1685                 warn++;
1686         } else {
1687                 if (trace_kprobe_nhit(tk) != 1) {
1688                         pr_warn("incorrect number of testprobe2 hits\n");
1689                         warn++;
1690                 }
1691
1692                 file = find_trace_probe_file(tk, top_trace_array());
1693                 if (WARN_ON_ONCE(file == NULL)) {
1694                         pr_warn("error on getting probe file.\n");
1695                         warn++;
1696                 } else
1697                         disable_trace_kprobe(tk, file);
1698         }
1699
1700         ret = trace_run_command("-:testprobe", create_trace_kprobe);
1701         if (WARN_ON_ONCE(ret)) {
1702                 pr_warn("error on deleting a probe.\n");
1703                 warn++;
1704         }
1705
1706         ret = trace_run_command("-:testprobe2", create_trace_kprobe);
1707         if (WARN_ON_ONCE(ret)) {
1708                 pr_warn("error on deleting a probe.\n");
1709                 warn++;
1710         }
1711
1712 end:
1713         release_all_trace_kprobes();
1714         /*
1715          * Wait for the optimizer work to finish. Otherwise it might fiddle
1716          * with probes in already freed __init text.
1717          */
1718         wait_for_kprobe_optimizer();
1719         if (warn)
1720                 pr_cont("NG: Some tests are failed. Please check them.\n");
1721         else
1722                 pr_cont("OK\n");
1723         return 0;
1724 }
1725
1726 late_initcall(kprobe_trace_self_tests_init);
1727
1728 #endif