trace-kprobe: Support delete probe syntax
[linux-2.6.git] / kernel / trace / trace_kprobe.c
1 /*
2  * Kprobes-based tracing events
3  *
4  * Created by Masami Hiramatsu <mhiramat@redhat.com>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18  */
19
20 #include <linux/module.h>
21 #include <linux/uaccess.h>
22 #include <linux/kprobes.h>
23 #include <linux/seq_file.h>
24 #include <linux/slab.h>
25 #include <linux/smp.h>
26 #include <linux/debugfs.h>
27 #include <linux/types.h>
28 #include <linux/string.h>
29 #include <linux/ctype.h>
30 #include <linux/ptrace.h>
31 #include <linux/perf_event.h>
32
33 #include "trace.h"
34 #include "trace_output.h"
35
36 #define MAX_TRACE_ARGS 128
37 #define MAX_ARGSTR_LEN 63
38 #define MAX_EVENT_NAME_LEN 64
39 #define KPROBE_EVENT_SYSTEM "kprobes"
40
41 /* Reserved field names */
42 #define FIELD_STRING_IP "__probe_ip"
43 #define FIELD_STRING_NARGS "__probe_nargs"
44 #define FIELD_STRING_RETIP "__probe_ret_ip"
45 #define FIELD_STRING_FUNC "__probe_func"
46
47 const char *reserved_field_names[] = {
48         "common_type",
49         "common_flags",
50         "common_preempt_count",
51         "common_pid",
52         "common_tgid",
53         "common_lock_depth",
54         FIELD_STRING_IP,
55         FIELD_STRING_NARGS,
56         FIELD_STRING_RETIP,
57         FIELD_STRING_FUNC,
58 };
59
60 struct fetch_func {
61         unsigned long (*func)(struct pt_regs *, void *);
62         void *data;
63 };
64
65 static __kprobes unsigned long call_fetch(struct fetch_func *f,
66                                           struct pt_regs *regs)
67 {
68         return f->func(regs, f->data);
69 }
70
71 /* fetch handlers */
72 static __kprobes unsigned long fetch_register(struct pt_regs *regs,
73                                               void *offset)
74 {
75         return regs_get_register(regs, (unsigned int)((unsigned long)offset));
76 }
77
78 static __kprobes unsigned long fetch_stack(struct pt_regs *regs,
79                                            void *num)
80 {
81         return regs_get_kernel_stack_nth(regs,
82                                          (unsigned int)((unsigned long)num));
83 }
84
85 static __kprobes unsigned long fetch_memory(struct pt_regs *regs, void *addr)
86 {
87         unsigned long retval;
88
89         if (probe_kernel_address(addr, retval))
90                 return 0;
91         return retval;
92 }
93
94 static __kprobes unsigned long fetch_argument(struct pt_regs *regs, void *num)
95 {
96         return regs_get_argument_nth(regs, (unsigned int)((unsigned long)num));
97 }
98
99 static __kprobes unsigned long fetch_retvalue(struct pt_regs *regs,
100                                               void *dummy)
101 {
102         return regs_return_value(regs);
103 }
104
105 static __kprobes unsigned long fetch_stack_address(struct pt_regs *regs,
106                                                    void *dummy)
107 {
108         return kernel_stack_pointer(regs);
109 }
110
111 /* Memory fetching by symbol */
112 struct symbol_cache {
113         char *symbol;
114         long offset;
115         unsigned long addr;
116 };
117
118 static unsigned long update_symbol_cache(struct symbol_cache *sc)
119 {
120         sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
121         if (sc->addr)
122                 sc->addr += sc->offset;
123         return sc->addr;
124 }
125
126 static void free_symbol_cache(struct symbol_cache *sc)
127 {
128         kfree(sc->symbol);
129         kfree(sc);
130 }
131
132 static struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
133 {
134         struct symbol_cache *sc;
135
136         if (!sym || strlen(sym) == 0)
137                 return NULL;
138         sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
139         if (!sc)
140                 return NULL;
141
142         sc->symbol = kstrdup(sym, GFP_KERNEL);
143         if (!sc->symbol) {
144                 kfree(sc);
145                 return NULL;
146         }
147         sc->offset = offset;
148
149         update_symbol_cache(sc);
150         return sc;
151 }
152
153 static __kprobes unsigned long fetch_symbol(struct pt_regs *regs, void *data)
154 {
155         struct symbol_cache *sc = data;
156
157         if (sc->addr)
158                 return fetch_memory(regs, (void *)sc->addr);
159         else
160                 return 0;
161 }
162
163 /* Special indirect memory access interface */
164 struct indirect_fetch_data {
165         struct fetch_func orig;
166         long offset;
167 };
168
169 static __kprobes unsigned long fetch_indirect(struct pt_regs *regs, void *data)
170 {
171         struct indirect_fetch_data *ind = data;
172         unsigned long addr;
173
174         addr = call_fetch(&ind->orig, regs);
175         if (addr) {
176                 addr += ind->offset;
177                 return fetch_memory(regs, (void *)addr);
178         } else
179                 return 0;
180 }
181
182 static __kprobes void free_indirect_fetch_data(struct indirect_fetch_data *data)
183 {
184         if (data->orig.func == fetch_indirect)
185                 free_indirect_fetch_data(data->orig.data);
186         else if (data->orig.func == fetch_symbol)
187                 free_symbol_cache(data->orig.data);
188         kfree(data);
189 }
190
191 /**
192  * Kprobe event core functions
193  */
194
195 struct probe_arg {
196         struct fetch_func       fetch;
197         const char              *name;
198 };
199
200 /* Flags for trace_probe */
201 #define TP_FLAG_TRACE   1
202 #define TP_FLAG_PROFILE 2
203
204 struct trace_probe {
205         struct list_head        list;
206         struct kretprobe        rp;     /* Use rp.kp for kprobe use */
207         unsigned long           nhit;
208         unsigned int            flags;  /* For TP_FLAG_* */
209         const char              *symbol;        /* symbol name */
210         struct ftrace_event_call        call;
211         struct trace_event              event;
212         unsigned int            nr_args;
213         struct probe_arg        args[];
214 };
215
216 #define SIZEOF_TRACE_PROBE(n)                   \
217         (offsetof(struct trace_probe, args) +   \
218         (sizeof(struct probe_arg) * (n)))
219
220 static __kprobes int probe_is_return(struct trace_probe *tp)
221 {
222         return tp->rp.handler != NULL;
223 }
224
225 static __kprobes const char *probe_symbol(struct trace_probe *tp)
226 {
227         return tp->symbol ? tp->symbol : "unknown";
228 }
229
230 static int probe_arg_string(char *buf, size_t n, struct fetch_func *ff)
231 {
232         int ret = -EINVAL;
233
234         if (ff->func == fetch_argument)
235                 ret = snprintf(buf, n, "$arg%lu", (unsigned long)ff->data);
236         else if (ff->func == fetch_register) {
237                 const char *name;
238                 name = regs_query_register_name((unsigned int)((long)ff->data));
239                 ret = snprintf(buf, n, "%%%s", name);
240         } else if (ff->func == fetch_stack)
241                 ret = snprintf(buf, n, "$stack%lu", (unsigned long)ff->data);
242         else if (ff->func == fetch_memory)
243                 ret = snprintf(buf, n, "@0x%p", ff->data);
244         else if (ff->func == fetch_symbol) {
245                 struct symbol_cache *sc = ff->data;
246                 if (sc->offset)
247                         ret = snprintf(buf, n, "@%s%+ld", sc->symbol,
248                                         sc->offset);
249                 else
250                         ret = snprintf(buf, n, "@%s", sc->symbol);
251         } else if (ff->func == fetch_retvalue)
252                 ret = snprintf(buf, n, "$retval");
253         else if (ff->func == fetch_stack_address)
254                 ret = snprintf(buf, n, "$stack");
255         else if (ff->func == fetch_indirect) {
256                 struct indirect_fetch_data *id = ff->data;
257                 size_t l = 0;
258                 ret = snprintf(buf, n, "%+ld(", id->offset);
259                 if (ret >= n)
260                         goto end;
261                 l += ret;
262                 ret = probe_arg_string(buf + l, n - l, &id->orig);
263                 if (ret < 0)
264                         goto end;
265                 l += ret;
266                 ret = snprintf(buf + l, n - l, ")");
267                 ret += l;
268         }
269 end:
270         if (ret >= n)
271                 return -ENOSPC;
272         return ret;
273 }
274
275 static int register_probe_event(struct trace_probe *tp);
276 static void unregister_probe_event(struct trace_probe *tp);
277
278 static DEFINE_MUTEX(probe_lock);
279 static LIST_HEAD(probe_list);
280
281 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
282 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
283                                 struct pt_regs *regs);
284
285 /*
286  * Allocate new trace_probe and initialize it (including kprobes).
287  */
288 static struct trace_probe *alloc_trace_probe(const char *group,
289                                              const char *event,
290                                              void *addr,
291                                              const char *symbol,
292                                              unsigned long offs,
293                                              int nargs, int is_return)
294 {
295         struct trace_probe *tp;
296
297         tp = kzalloc(SIZEOF_TRACE_PROBE(nargs), GFP_KERNEL);
298         if (!tp)
299                 return ERR_PTR(-ENOMEM);
300
301         if (symbol) {
302                 tp->symbol = kstrdup(symbol, GFP_KERNEL);
303                 if (!tp->symbol)
304                         goto error;
305                 tp->rp.kp.symbol_name = tp->symbol;
306                 tp->rp.kp.offset = offs;
307         } else
308                 tp->rp.kp.addr = addr;
309
310         if (is_return)
311                 tp->rp.handler = kretprobe_dispatcher;
312         else
313                 tp->rp.kp.pre_handler = kprobe_dispatcher;
314
315         if (!event)
316                 goto error;
317         tp->call.name = kstrdup(event, GFP_KERNEL);
318         if (!tp->call.name)
319                 goto error;
320
321         if (!group)
322                 goto error;
323         tp->call.system = kstrdup(group, GFP_KERNEL);
324         if (!tp->call.system)
325                 goto error;
326
327         INIT_LIST_HEAD(&tp->list);
328         return tp;
329 error:
330         kfree(tp->call.name);
331         kfree(tp->symbol);
332         kfree(tp);
333         return ERR_PTR(-ENOMEM);
334 }
335
336 static void free_probe_arg(struct probe_arg *arg)
337 {
338         if (arg->fetch.func == fetch_symbol)
339                 free_symbol_cache(arg->fetch.data);
340         else if (arg->fetch.func == fetch_indirect)
341                 free_indirect_fetch_data(arg->fetch.data);
342         kfree(arg->name);
343 }
344
345 static void free_trace_probe(struct trace_probe *tp)
346 {
347         int i;
348
349         for (i = 0; i < tp->nr_args; i++)
350                 free_probe_arg(&tp->args[i]);
351
352         kfree(tp->call.system);
353         kfree(tp->call.name);
354         kfree(tp->symbol);
355         kfree(tp);
356 }
357
358 static struct trace_probe *find_probe_event(const char *event,
359                                             const char *group)
360 {
361         struct trace_probe *tp;
362
363         list_for_each_entry(tp, &probe_list, list)
364                 if (strcmp(tp->call.name, event) == 0 &&
365                     strcmp(tp->call.system, group) == 0)
366                         return tp;
367         return NULL;
368 }
369
370 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
371 static void unregister_trace_probe(struct trace_probe *tp)
372 {
373         if (probe_is_return(tp))
374                 unregister_kretprobe(&tp->rp);
375         else
376                 unregister_kprobe(&tp->rp.kp);
377         list_del(&tp->list);
378         unregister_probe_event(tp);
379 }
380
381 /* Register a trace_probe and probe_event */
382 static int register_trace_probe(struct trace_probe *tp)
383 {
384         struct trace_probe *old_tp;
385         int ret;
386
387         mutex_lock(&probe_lock);
388
389         /* register as an event */
390         old_tp = find_probe_event(tp->call.name, tp->call.system);
391         if (old_tp) {
392                 /* delete old event */
393                 unregister_trace_probe(old_tp);
394                 free_trace_probe(old_tp);
395         }
396         ret = register_probe_event(tp);
397         if (ret) {
398                 pr_warning("Faild to register probe event(%d)\n", ret);
399                 goto end;
400         }
401
402         tp->rp.kp.flags |= KPROBE_FLAG_DISABLED;
403         if (probe_is_return(tp))
404                 ret = register_kretprobe(&tp->rp);
405         else
406                 ret = register_kprobe(&tp->rp.kp);
407
408         if (ret) {
409                 pr_warning("Could not insert probe(%d)\n", ret);
410                 if (ret == -EILSEQ) {
411                         pr_warning("Probing address(0x%p) is not an "
412                                    "instruction boundary.\n",
413                                    tp->rp.kp.addr);
414                         ret = -EINVAL;
415                 }
416                 unregister_probe_event(tp);
417         } else
418                 list_add_tail(&tp->list, &probe_list);
419 end:
420         mutex_unlock(&probe_lock);
421         return ret;
422 }
423
424 /* Split symbol and offset. */
425 static int split_symbol_offset(char *symbol, unsigned long *offset)
426 {
427         char *tmp;
428         int ret;
429
430         if (!offset)
431                 return -EINVAL;
432
433         tmp = strchr(symbol, '+');
434         if (tmp) {
435                 /* skip sign because strict_strtol doesn't accept '+' */
436                 ret = strict_strtoul(tmp + 1, 0, offset);
437                 if (ret)
438                         return ret;
439                 *tmp = '\0';
440         } else
441                 *offset = 0;
442         return 0;
443 }
444
445 #define PARAM_MAX_ARGS 16
446 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
447
448 static int parse_probe_vars(char *arg, struct fetch_func *ff, int is_return)
449 {
450         int ret = 0;
451         unsigned long param;
452
453         if (strcmp(arg, "retval") == 0) {
454                 if (is_return) {
455                         ff->func = fetch_retvalue;
456                         ff->data = NULL;
457                 } else
458                         ret = -EINVAL;
459         } else if (strncmp(arg, "stack", 5) == 0) {
460                 if (arg[5] == '\0') {
461                         ff->func = fetch_stack_address;
462                         ff->data = NULL;
463                 } else if (isdigit(arg[5])) {
464                         ret = strict_strtoul(arg + 5, 10, &param);
465                         if (ret || param > PARAM_MAX_STACK)
466                                 ret = -EINVAL;
467                         else {
468                                 ff->func = fetch_stack;
469                                 ff->data = (void *)param;
470                         }
471                 } else
472                         ret = -EINVAL;
473         } else if (strncmp(arg, "arg", 3) == 0 && isdigit(arg[3])) {
474                 ret = strict_strtoul(arg + 3, 10, &param);
475                 if (ret || param > PARAM_MAX_ARGS)
476                         ret = -EINVAL;
477                 else {
478                         ff->func = fetch_argument;
479                         ff->data = (void *)param;
480                 }
481         } else
482                 ret = -EINVAL;
483         return ret;
484 }
485
486 /* Recursive argument parser */
487 static int __parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
488 {
489         int ret = 0;
490         unsigned long param;
491         long offset;
492         char *tmp;
493
494         switch (arg[0]) {
495         case '$':
496                 ret = parse_probe_vars(arg + 1, ff, is_return);
497                 break;
498         case '%':       /* named register */
499                 ret = regs_query_register_offset(arg + 1);
500                 if (ret >= 0) {
501                         ff->func = fetch_register;
502                         ff->data = (void *)(unsigned long)ret;
503                         ret = 0;
504                 }
505                 break;
506         case '@':       /* memory or symbol */
507                 if (isdigit(arg[1])) {
508                         ret = strict_strtoul(arg + 1, 0, &param);
509                         if (ret)
510                                 break;
511                         ff->func = fetch_memory;
512                         ff->data = (void *)param;
513                 } else {
514                         ret = split_symbol_offset(arg + 1, &offset);
515                         if (ret)
516                                 break;
517                         ff->data = alloc_symbol_cache(arg + 1, offset);
518                         if (ff->data)
519                                 ff->func = fetch_symbol;
520                         else
521                                 ret = -EINVAL;
522                 }
523                 break;
524         case '+':       /* indirect memory */
525         case '-':
526                 tmp = strchr(arg, '(');
527                 if (!tmp) {
528                         ret = -EINVAL;
529                         break;
530                 }
531                 *tmp = '\0';
532                 ret = strict_strtol(arg + 1, 0, &offset);
533                 if (ret)
534                         break;
535                 if (arg[0] == '-')
536                         offset = -offset;
537                 arg = tmp + 1;
538                 tmp = strrchr(arg, ')');
539                 if (tmp) {
540                         struct indirect_fetch_data *id;
541                         *tmp = '\0';
542                         id = kzalloc(sizeof(struct indirect_fetch_data),
543                                      GFP_KERNEL);
544                         if (!id)
545                                 return -ENOMEM;
546                         id->offset = offset;
547                         ret = __parse_probe_arg(arg, &id->orig, is_return);
548                         if (ret)
549                                 kfree(id);
550                         else {
551                                 ff->func = fetch_indirect;
552                                 ff->data = (void *)id;
553                         }
554                 } else
555                         ret = -EINVAL;
556                 break;
557         default:
558                 /* TODO: support custom handler */
559                 ret = -EINVAL;
560         }
561         return ret;
562 }
563
564 /* String length checking wrapper */
565 static int parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
566 {
567         if (strlen(arg) > MAX_ARGSTR_LEN) {
568                 pr_info("Argument is too long.: %s\n",  arg);
569                 return -ENOSPC;
570         }
571         return __parse_probe_arg(arg, ff, is_return);
572 }
573
574 /* Return 1 if name is reserved or already used by another argument */
575 static int conflict_field_name(const char *name,
576                                struct probe_arg *args, int narg)
577 {
578         int i;
579         for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
580                 if (strcmp(reserved_field_names[i], name) == 0)
581                         return 1;
582         for (i = 0; i < narg; i++)
583                 if (strcmp(args[i].name, name) == 0)
584                         return 1;
585         return 0;
586 }
587
588 static int create_trace_probe(int argc, char **argv)
589 {
590         /*
591          * Argument syntax:
592          *  - Add kprobe: p[:[GRP/]EVENT] KSYM[+OFFS]|KADDR [FETCHARGS]
593          *  - Add kretprobe: r[:[GRP/]EVENT] KSYM[+0] [FETCHARGS]
594          * Fetch args:
595          *  $argN       : fetch Nth of function argument. (N:0-)
596          *  $retval     : fetch return value
597          *  $stack      : fetch stack address
598          *  $stackN     : fetch Nth of stack (N:0-)
599          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
600          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
601          *  %REG        : fetch register REG
602          * Indirect memory fetch:
603          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
604          * Alias name of args:
605          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
606          */
607         struct trace_probe *tp;
608         int i, ret = 0;
609         int is_return = 0, is_delete = 0;
610         char *symbol = NULL, *event = NULL, *arg = NULL, *group = NULL;
611         unsigned long offset = 0;
612         void *addr = NULL;
613         char buf[MAX_EVENT_NAME_LEN];
614
615         /* argc must be >= 1 */
616         if (argv[0][0] == 'p')
617                 is_return = 0;
618         else if (argv[0][0] == 'r')
619                 is_return = 1;
620         else if (argv[0][0] == '-')
621                 is_delete = 1;
622         else {
623                 pr_info("Probe definition must be started with 'p', 'r' or"
624                         " '-'.\n");
625                 return -EINVAL;
626         }
627
628         if (argv[0][1] == ':') {
629                 event = &argv[0][2];
630                 if (strchr(event, '/')) {
631                         group = event;
632                         event = strchr(group, '/') + 1;
633                         event[-1] = '\0';
634                         if (strlen(group) == 0) {
635                                 pr_info("Group name is not specifiled\n");
636                                 return -EINVAL;
637                         }
638                 }
639                 if (strlen(event) == 0) {
640                         pr_info("Event name is not specifiled\n");
641                         return -EINVAL;
642                 }
643         }
644         if (!group)
645                 group = KPROBE_EVENT_SYSTEM;
646
647         if (is_delete) {
648                 if (!event) {
649                         pr_info("Delete command needs an event name.\n");
650                         return -EINVAL;
651                 }
652                 tp = find_probe_event(event, group);
653                 if (!tp) {
654                         pr_info("Event %s/%s doesn't exist.\n", group, event);
655                         return -ENOENT;
656                 }
657                 /* delete an event */
658                 unregister_trace_probe(tp);
659                 free_trace_probe(tp);
660                 return 0;
661         }
662
663         if (argc < 2) {
664                 pr_info("Probe point is not specified.\n");
665                 return -EINVAL;
666         }
667         if (isdigit(argv[1][0])) {
668                 if (is_return) {
669                         pr_info("Return probe point must be a symbol.\n");
670                         return -EINVAL;
671                 }
672                 /* an address specified */
673                 ret = strict_strtoul(&argv[0][2], 0, (unsigned long *)&addr);
674                 if (ret) {
675                         pr_info("Failed to parse address.\n");
676                         return ret;
677                 }
678         } else {
679                 /* a symbol specified */
680                 symbol = argv[1];
681                 /* TODO: support .init module functions */
682                 ret = split_symbol_offset(symbol, &offset);
683                 if (ret) {
684                         pr_info("Failed to parse symbol.\n");
685                         return ret;
686                 }
687                 if (offset && is_return) {
688                         pr_info("Return probe must be used without offset.\n");
689                         return -EINVAL;
690                 }
691         }
692         argc -= 2; argv += 2;
693
694         /* setup a probe */
695         if (!event) {
696                 /* Make a new event name */
697                 if (symbol)
698                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c@%s%+ld",
699                                  is_return ? 'r' : 'p', symbol, offset);
700                 else
701                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c@0x%p",
702                                  is_return ? 'r' : 'p', addr);
703                 event = buf;
704         }
705         tp = alloc_trace_probe(group, event, addr, symbol, offset, argc,
706                                is_return);
707         if (IS_ERR(tp)) {
708                 pr_info("Failed to allocate trace_probe.(%d)\n",
709                         (int)PTR_ERR(tp));
710                 return PTR_ERR(tp);
711         }
712
713         /* parse arguments */
714         ret = 0;
715         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
716                 /* Parse argument name */
717                 arg = strchr(argv[i], '=');
718                 if (arg)
719                         *arg++ = '\0';
720                 else
721                         arg = argv[i];
722
723                 if (conflict_field_name(argv[i], tp->args, i)) {
724                         pr_info("Argument%d name '%s' conflicts with "
725                                 "another field.\n", i, argv[i]);
726                         ret = -EINVAL;
727                         goto error;
728                 }
729
730                 tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
731                 if (!tp->args[i].name) {
732                         pr_info("Failed to allocate argument%d name '%s'.\n",
733                                 i, argv[i]);
734                         ret = -ENOMEM;
735                         goto error;
736                 }
737
738                 /* Parse fetch argument */
739                 ret = parse_probe_arg(arg, &tp->args[i].fetch, is_return);
740                 if (ret) {
741                         pr_info("Parse error at argument%d. (%d)\n", i, ret);
742                         kfree(tp->args[i].name);
743                         goto error;
744                 }
745
746                 tp->nr_args++;
747         }
748
749         ret = register_trace_probe(tp);
750         if (ret)
751                 goto error;
752         return 0;
753
754 error:
755         free_trace_probe(tp);
756         return ret;
757 }
758
759 static void cleanup_all_probes(void)
760 {
761         struct trace_probe *tp;
762
763         mutex_lock(&probe_lock);
764         /* TODO: Use batch unregistration */
765         while (!list_empty(&probe_list)) {
766                 tp = list_entry(probe_list.next, struct trace_probe, list);
767                 unregister_trace_probe(tp);
768                 free_trace_probe(tp);
769         }
770         mutex_unlock(&probe_lock);
771 }
772
773
774 /* Probes listing interfaces */
775 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
776 {
777         mutex_lock(&probe_lock);
778         return seq_list_start(&probe_list, *pos);
779 }
780
781 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
782 {
783         return seq_list_next(v, &probe_list, pos);
784 }
785
786 static void probes_seq_stop(struct seq_file *m, void *v)
787 {
788         mutex_unlock(&probe_lock);
789 }
790
791 static int probes_seq_show(struct seq_file *m, void *v)
792 {
793         struct trace_probe *tp = v;
794         int i, ret;
795         char buf[MAX_ARGSTR_LEN + 1];
796
797         seq_printf(m, "%c", probe_is_return(tp) ? 'r' : 'p');
798         seq_printf(m, ":%s/%s", tp->call.system, tp->call.name);
799
800         if (!tp->symbol)
801                 seq_printf(m, " 0x%p", tp->rp.kp.addr);
802         else if (tp->rp.kp.offset)
803                 seq_printf(m, " %s+%u", probe_symbol(tp), tp->rp.kp.offset);
804         else
805                 seq_printf(m, " %s", probe_symbol(tp));
806
807         for (i = 0; i < tp->nr_args; i++) {
808                 ret = probe_arg_string(buf, MAX_ARGSTR_LEN, &tp->args[i].fetch);
809                 if (ret < 0) {
810                         pr_warning("Argument%d decoding error(%d).\n", i, ret);
811                         return ret;
812                 }
813                 seq_printf(m, " %s=%s", tp->args[i].name, buf);
814         }
815         seq_printf(m, "\n");
816         return 0;
817 }
818
819 static const struct seq_operations probes_seq_op = {
820         .start  = probes_seq_start,
821         .next   = probes_seq_next,
822         .stop   = probes_seq_stop,
823         .show   = probes_seq_show
824 };
825
826 static int probes_open(struct inode *inode, struct file *file)
827 {
828         if ((file->f_mode & FMODE_WRITE) &&
829             (file->f_flags & O_TRUNC))
830                 cleanup_all_probes();
831
832         return seq_open(file, &probes_seq_op);
833 }
834
835 static int command_trace_probe(const char *buf)
836 {
837         char **argv;
838         int argc = 0, ret = 0;
839
840         argv = argv_split(GFP_KERNEL, buf, &argc);
841         if (!argv)
842                 return -ENOMEM;
843
844         if (argc)
845                 ret = create_trace_probe(argc, argv);
846
847         argv_free(argv);
848         return ret;
849 }
850
851 #define WRITE_BUFSIZE 128
852
853 static ssize_t probes_write(struct file *file, const char __user *buffer,
854                             size_t count, loff_t *ppos)
855 {
856         char *kbuf, *tmp;
857         int ret;
858         size_t done;
859         size_t size;
860
861         kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
862         if (!kbuf)
863                 return -ENOMEM;
864
865         ret = done = 0;
866         while (done < count) {
867                 size = count - done;
868                 if (size >= WRITE_BUFSIZE)
869                         size = WRITE_BUFSIZE - 1;
870                 if (copy_from_user(kbuf, buffer + done, size)) {
871                         ret = -EFAULT;
872                         goto out;
873                 }
874                 kbuf[size] = '\0';
875                 tmp = strchr(kbuf, '\n');
876                 if (tmp) {
877                         *tmp = '\0';
878                         size = tmp - kbuf + 1;
879                 } else if (done + size < count) {
880                         pr_warning("Line length is too long: "
881                                    "Should be less than %d.", WRITE_BUFSIZE);
882                         ret = -EINVAL;
883                         goto out;
884                 }
885                 done += size;
886                 /* Remove comments */
887                 tmp = strchr(kbuf, '#');
888                 if (tmp)
889                         *tmp = '\0';
890
891                 ret = command_trace_probe(kbuf);
892                 if (ret)
893                         goto out;
894         }
895         ret = done;
896 out:
897         kfree(kbuf);
898         return ret;
899 }
900
901 static const struct file_operations kprobe_events_ops = {
902         .owner          = THIS_MODULE,
903         .open           = probes_open,
904         .read           = seq_read,
905         .llseek         = seq_lseek,
906         .release        = seq_release,
907         .write          = probes_write,
908 };
909
910 /* Probes profiling interfaces */
911 static int probes_profile_seq_show(struct seq_file *m, void *v)
912 {
913         struct trace_probe *tp = v;
914
915         seq_printf(m, "  %-44s %15lu %15lu\n", tp->call.name, tp->nhit,
916                    tp->rp.kp.nmissed);
917
918         return 0;
919 }
920
921 static const struct seq_operations profile_seq_op = {
922         .start  = probes_seq_start,
923         .next   = probes_seq_next,
924         .stop   = probes_seq_stop,
925         .show   = probes_profile_seq_show
926 };
927
928 static int profile_open(struct inode *inode, struct file *file)
929 {
930         return seq_open(file, &profile_seq_op);
931 }
932
933 static const struct file_operations kprobe_profile_ops = {
934         .owner          = THIS_MODULE,
935         .open           = profile_open,
936         .read           = seq_read,
937         .llseek         = seq_lseek,
938         .release        = seq_release,
939 };
940
941 /* Kprobe handler */
942 static __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
943 {
944         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
945         struct kprobe_trace_entry *entry;
946         struct ring_buffer_event *event;
947         struct ring_buffer *buffer;
948         int size, i, pc;
949         unsigned long irq_flags;
950         struct ftrace_event_call *call = &tp->call;
951
952         tp->nhit++;
953
954         local_save_flags(irq_flags);
955         pc = preempt_count();
956
957         size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args);
958
959         event = trace_current_buffer_lock_reserve(&buffer, call->id, size,
960                                                   irq_flags, pc);
961         if (!event)
962                 return 0;
963
964         entry = ring_buffer_event_data(event);
965         entry->nargs = tp->nr_args;
966         entry->ip = (unsigned long)kp->addr;
967         for (i = 0; i < tp->nr_args; i++)
968                 entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
969
970         if (!filter_current_check_discard(buffer, call, entry, event))
971                 trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
972         return 0;
973 }
974
975 /* Kretprobe handler */
976 static __kprobes int kretprobe_trace_func(struct kretprobe_instance *ri,
977                                           struct pt_regs *regs)
978 {
979         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
980         struct kretprobe_trace_entry *entry;
981         struct ring_buffer_event *event;
982         struct ring_buffer *buffer;
983         int size, i, pc;
984         unsigned long irq_flags;
985         struct ftrace_event_call *call = &tp->call;
986
987         local_save_flags(irq_flags);
988         pc = preempt_count();
989
990         size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args);
991
992         event = trace_current_buffer_lock_reserve(&buffer, call->id, size,
993                                                   irq_flags, pc);
994         if (!event)
995                 return 0;
996
997         entry = ring_buffer_event_data(event);
998         entry->nargs = tp->nr_args;
999         entry->func = (unsigned long)tp->rp.kp.addr;
1000         entry->ret_ip = (unsigned long)ri->ret_addr;
1001         for (i = 0; i < tp->nr_args; i++)
1002                 entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
1003
1004         if (!filter_current_check_discard(buffer, call, entry, event))
1005                 trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
1006
1007         return 0;
1008 }
1009
1010 /* Event entry printers */
1011 enum print_line_t
1012 print_kprobe_event(struct trace_iterator *iter, int flags)
1013 {
1014         struct kprobe_trace_entry *field;
1015         struct trace_seq *s = &iter->seq;
1016         struct trace_event *event;
1017         struct trace_probe *tp;
1018         int i;
1019
1020         field = (struct kprobe_trace_entry *)iter->ent;
1021         event = ftrace_find_event(field->ent.type);
1022         tp = container_of(event, struct trace_probe, event);
1023
1024         if (!trace_seq_printf(s, "%s: (", tp->call.name))
1025                 goto partial;
1026
1027         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1028                 goto partial;
1029
1030         if (!trace_seq_puts(s, ")"))
1031                 goto partial;
1032
1033         for (i = 0; i < field->nargs; i++)
1034                 if (!trace_seq_printf(s, " %s=%lx",
1035                                       tp->args[i].name, field->args[i]))
1036                         goto partial;
1037
1038         if (!trace_seq_puts(s, "\n"))
1039                 goto partial;
1040
1041         return TRACE_TYPE_HANDLED;
1042 partial:
1043         return TRACE_TYPE_PARTIAL_LINE;
1044 }
1045
1046 enum print_line_t
1047 print_kretprobe_event(struct trace_iterator *iter, int flags)
1048 {
1049         struct kretprobe_trace_entry *field;
1050         struct trace_seq *s = &iter->seq;
1051         struct trace_event *event;
1052         struct trace_probe *tp;
1053         int i;
1054
1055         field = (struct kretprobe_trace_entry *)iter->ent;
1056         event = ftrace_find_event(field->ent.type);
1057         tp = container_of(event, struct trace_probe, event);
1058
1059         if (!trace_seq_printf(s, "%s: (", tp->call.name))
1060                 goto partial;
1061
1062         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1063                 goto partial;
1064
1065         if (!trace_seq_puts(s, " <- "))
1066                 goto partial;
1067
1068         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1069                 goto partial;
1070
1071         if (!trace_seq_puts(s, ")"))
1072                 goto partial;
1073
1074         for (i = 0; i < field->nargs; i++)
1075                 if (!trace_seq_printf(s, " %s=%lx",
1076                                       tp->args[i].name, field->args[i]))
1077                         goto partial;
1078
1079         if (!trace_seq_puts(s, "\n"))
1080                 goto partial;
1081
1082         return TRACE_TYPE_HANDLED;
1083 partial:
1084         return TRACE_TYPE_PARTIAL_LINE;
1085 }
1086
1087 static int probe_event_enable(struct ftrace_event_call *call)
1088 {
1089         struct trace_probe *tp = (struct trace_probe *)call->data;
1090
1091         tp->flags |= TP_FLAG_TRACE;
1092         if (probe_is_return(tp))
1093                 return enable_kretprobe(&tp->rp);
1094         else
1095                 return enable_kprobe(&tp->rp.kp);
1096 }
1097
1098 static void probe_event_disable(struct ftrace_event_call *call)
1099 {
1100         struct trace_probe *tp = (struct trace_probe *)call->data;
1101
1102         tp->flags &= ~TP_FLAG_TRACE;
1103         if (!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE))) {
1104                 if (probe_is_return(tp))
1105                         disable_kretprobe(&tp->rp);
1106                 else
1107                         disable_kprobe(&tp->rp.kp);
1108         }
1109 }
1110
1111 static int probe_event_raw_init(struct ftrace_event_call *event_call)
1112 {
1113         INIT_LIST_HEAD(&event_call->fields);
1114
1115         return 0;
1116 }
1117
1118 #undef DEFINE_FIELD
1119 #define DEFINE_FIELD(type, item, name, is_signed)                       \
1120         do {                                                            \
1121                 ret = trace_define_field(event_call, #type, name,       \
1122                                          offsetof(typeof(field), item), \
1123                                          sizeof(field.item), is_signed, \
1124                                          FILTER_OTHER);                 \
1125                 if (ret)                                                \
1126                         return ret;                                     \
1127         } while (0)
1128
1129 static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
1130 {
1131         int ret, i;
1132         struct kprobe_trace_entry field;
1133         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1134
1135         ret = trace_define_common_fields(event_call);
1136         if (!ret)
1137                 return ret;
1138
1139         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1140         DEFINE_FIELD(int, nargs, FIELD_STRING_NARGS, 1);
1141         /* Set argument names as fields */
1142         for (i = 0; i < tp->nr_args; i++)
1143                 DEFINE_FIELD(unsigned long, args[i], tp->args[i].name, 0);
1144         return 0;
1145 }
1146
1147 static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
1148 {
1149         int ret, i;
1150         struct kretprobe_trace_entry field;
1151         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1152
1153         ret = trace_define_common_fields(event_call);
1154         if (!ret)
1155                 return ret;
1156
1157         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1158         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1159         DEFINE_FIELD(int, nargs, FIELD_STRING_NARGS, 1);
1160         /* Set argument names as fields */
1161         for (i = 0; i < tp->nr_args; i++)
1162                 DEFINE_FIELD(unsigned long, args[i], tp->args[i].name, 0);
1163         return 0;
1164 }
1165
1166 static int __probe_event_show_format(struct trace_seq *s,
1167                                      struct trace_probe *tp, const char *fmt,
1168                                      const char *arg)
1169 {
1170         int i;
1171
1172         /* Show format */
1173         if (!trace_seq_printf(s, "\nprint fmt: \"%s", fmt))
1174                 return 0;
1175
1176         for (i = 0; i < tp->nr_args; i++)
1177                 if (!trace_seq_printf(s, " %s=%%lx", tp->args[i].name))
1178                         return 0;
1179
1180         if (!trace_seq_printf(s, "\", %s", arg))
1181                 return 0;
1182
1183         for (i = 0; i < tp->nr_args; i++)
1184                 if (!trace_seq_printf(s, ", REC->%s", tp->args[i].name))
1185                         return 0;
1186
1187         return trace_seq_puts(s, "\n");
1188 }
1189
1190 #undef SHOW_FIELD
1191 #define SHOW_FIELD(type, item, name)                                    \
1192         do {                                                            \
1193                 ret = trace_seq_printf(s, "\tfield: " #type " %s;\t"    \
1194                                 "offset:%u;\tsize:%u;\n", name,         \
1195                                 (unsigned int)offsetof(typeof(field), item),\
1196                                 (unsigned int)sizeof(type));            \
1197                 if (!ret)                                               \
1198                         return 0;                                       \
1199         } while (0)
1200
1201 static int kprobe_event_show_format(struct ftrace_event_call *call,
1202                                     struct trace_seq *s)
1203 {
1204         struct kprobe_trace_entry field __attribute__((unused));
1205         int ret, i;
1206         struct trace_probe *tp = (struct trace_probe *)call->data;
1207
1208         SHOW_FIELD(unsigned long, ip, FIELD_STRING_IP);
1209         SHOW_FIELD(int, nargs, FIELD_STRING_NARGS);
1210
1211         /* Show fields */
1212         for (i = 0; i < tp->nr_args; i++)
1213                 SHOW_FIELD(unsigned long, args[i], tp->args[i].name);
1214         trace_seq_puts(s, "\n");
1215
1216         return __probe_event_show_format(s, tp, "(%lx)",
1217                                          "REC->" FIELD_STRING_IP);
1218 }
1219
1220 static int kretprobe_event_show_format(struct ftrace_event_call *call,
1221                                        struct trace_seq *s)
1222 {
1223         struct kretprobe_trace_entry field __attribute__((unused));
1224         int ret, i;
1225         struct trace_probe *tp = (struct trace_probe *)call->data;
1226
1227         SHOW_FIELD(unsigned long, func, FIELD_STRING_FUNC);
1228         SHOW_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP);
1229         SHOW_FIELD(int, nargs, FIELD_STRING_NARGS);
1230
1231         /* Show fields */
1232         for (i = 0; i < tp->nr_args; i++)
1233                 SHOW_FIELD(unsigned long, args[i], tp->args[i].name);
1234         trace_seq_puts(s, "\n");
1235
1236         return __probe_event_show_format(s, tp, "(%lx <- %lx)",
1237                                          "REC->" FIELD_STRING_FUNC
1238                                          ", REC->" FIELD_STRING_RETIP);
1239 }
1240
1241 #ifdef CONFIG_EVENT_PROFILE
1242
1243 /* Kprobe profile handler */
1244 static __kprobes int kprobe_profile_func(struct kprobe *kp,
1245                                          struct pt_regs *regs)
1246 {
1247         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1248         struct ftrace_event_call *call = &tp->call;
1249         struct kprobe_trace_entry *entry;
1250         struct trace_entry *ent;
1251         int size, __size, i, pc, __cpu;
1252         unsigned long irq_flags;
1253         char *trace_buf;
1254         char *raw_data;
1255         int rctx;
1256
1257         pc = preempt_count();
1258         __size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args);
1259         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1260         size -= sizeof(u32);
1261         if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE,
1262                      "profile buffer not large enough"))
1263                 return 0;
1264
1265         /*
1266          * Protect the non nmi buffer
1267          * This also protects the rcu read side
1268          */
1269         local_irq_save(irq_flags);
1270
1271         rctx = perf_swevent_get_recursion_context();
1272         if (rctx < 0)
1273                 goto end_recursion;
1274
1275         __cpu = smp_processor_id();
1276
1277         if (in_nmi())
1278                 trace_buf = rcu_dereference(perf_trace_buf_nmi);
1279         else
1280                 trace_buf = rcu_dereference(perf_trace_buf);
1281
1282         if (!trace_buf)
1283                 goto end;
1284
1285         raw_data = per_cpu_ptr(trace_buf, __cpu);
1286
1287         /* Zero dead bytes from alignment to avoid buffer leak to userspace */
1288         *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
1289         entry = (struct kprobe_trace_entry *)raw_data;
1290         ent = &entry->ent;
1291
1292         tracing_generic_entry_update(ent, irq_flags, pc);
1293         ent->type = call->id;
1294         entry->nargs = tp->nr_args;
1295         entry->ip = (unsigned long)kp->addr;
1296         for (i = 0; i < tp->nr_args; i++)
1297                 entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
1298         perf_tp_event(call->id, entry->ip, 1, entry, size);
1299
1300 end:
1301         perf_swevent_put_recursion_context(rctx);
1302 end_recursion:
1303         local_irq_restore(irq_flags);
1304
1305         return 0;
1306 }
1307
1308 /* Kretprobe profile handler */
1309 static __kprobes int kretprobe_profile_func(struct kretprobe_instance *ri,
1310                                             struct pt_regs *regs)
1311 {
1312         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1313         struct ftrace_event_call *call = &tp->call;
1314         struct kretprobe_trace_entry *entry;
1315         struct trace_entry *ent;
1316         int size, __size, i, pc, __cpu;
1317         unsigned long irq_flags;
1318         char *trace_buf;
1319         char *raw_data;
1320         int rctx;
1321
1322         pc = preempt_count();
1323         __size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args);
1324         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1325         size -= sizeof(u32);
1326         if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE,
1327                      "profile buffer not large enough"))
1328                 return 0;
1329
1330         /*
1331          * Protect the non nmi buffer
1332          * This also protects the rcu read side
1333          */
1334         local_irq_save(irq_flags);
1335
1336         rctx = perf_swevent_get_recursion_context();
1337         if (rctx < 0)
1338                 goto end_recursion;
1339
1340         __cpu = smp_processor_id();
1341
1342         if (in_nmi())
1343                 trace_buf = rcu_dereference(perf_trace_buf_nmi);
1344         else
1345                 trace_buf = rcu_dereference(perf_trace_buf);
1346
1347         if (!trace_buf)
1348                 goto end;
1349
1350         raw_data = per_cpu_ptr(trace_buf, __cpu);
1351
1352         /* Zero dead bytes from alignment to avoid buffer leak to userspace */
1353         *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
1354         entry = (struct kretprobe_trace_entry *)raw_data;
1355         ent = &entry->ent;
1356
1357         tracing_generic_entry_update(ent, irq_flags, pc);
1358         ent->type = call->id;
1359         entry->nargs = tp->nr_args;
1360         entry->func = (unsigned long)tp->rp.kp.addr;
1361         entry->ret_ip = (unsigned long)ri->ret_addr;
1362         for (i = 0; i < tp->nr_args; i++)
1363                 entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
1364         perf_tp_event(call->id, entry->ret_ip, 1, entry, size);
1365
1366 end:
1367         perf_swevent_put_recursion_context(rctx);
1368 end_recursion:
1369         local_irq_restore(irq_flags);
1370
1371         return 0;
1372 }
1373
1374 static int probe_profile_enable(struct ftrace_event_call *call)
1375 {
1376         struct trace_probe *tp = (struct trace_probe *)call->data;
1377
1378         tp->flags |= TP_FLAG_PROFILE;
1379
1380         if (probe_is_return(tp))
1381                 return enable_kretprobe(&tp->rp);
1382         else
1383                 return enable_kprobe(&tp->rp.kp);
1384 }
1385
1386 static void probe_profile_disable(struct ftrace_event_call *call)
1387 {
1388         struct trace_probe *tp = (struct trace_probe *)call->data;
1389
1390         tp->flags &= ~TP_FLAG_PROFILE;
1391
1392         if (!(tp->flags & TP_FLAG_TRACE)) {
1393                 if (probe_is_return(tp))
1394                         disable_kretprobe(&tp->rp);
1395                 else
1396                         disable_kprobe(&tp->rp.kp);
1397         }
1398 }
1399 #endif  /* CONFIG_EVENT_PROFILE */
1400
1401
1402 static __kprobes
1403 int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1404 {
1405         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1406
1407         if (tp->flags & TP_FLAG_TRACE)
1408                 kprobe_trace_func(kp, regs);
1409 #ifdef CONFIG_EVENT_PROFILE
1410         if (tp->flags & TP_FLAG_PROFILE)
1411                 kprobe_profile_func(kp, regs);
1412 #endif  /* CONFIG_EVENT_PROFILE */
1413         return 0;       /* We don't tweek kernel, so just return 0 */
1414 }
1415
1416 static __kprobes
1417 int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1418 {
1419         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1420
1421         if (tp->flags & TP_FLAG_TRACE)
1422                 kretprobe_trace_func(ri, regs);
1423 #ifdef CONFIG_EVENT_PROFILE
1424         if (tp->flags & TP_FLAG_PROFILE)
1425                 kretprobe_profile_func(ri, regs);
1426 #endif  /* CONFIG_EVENT_PROFILE */
1427         return 0;       /* We don't tweek kernel, so just return 0 */
1428 }
1429
1430 static int register_probe_event(struct trace_probe *tp)
1431 {
1432         struct ftrace_event_call *call = &tp->call;
1433         int ret;
1434
1435         /* Initialize ftrace_event_call */
1436         if (probe_is_return(tp)) {
1437                 tp->event.trace = print_kretprobe_event;
1438                 call->raw_init = probe_event_raw_init;
1439                 call->show_format = kretprobe_event_show_format;
1440                 call->define_fields = kretprobe_event_define_fields;
1441         } else {
1442                 tp->event.trace = print_kprobe_event;
1443                 call->raw_init = probe_event_raw_init;
1444                 call->show_format = kprobe_event_show_format;
1445                 call->define_fields = kprobe_event_define_fields;
1446         }
1447         call->event = &tp->event;
1448         call->id = register_ftrace_event(&tp->event);
1449         if (!call->id)
1450                 return -ENODEV;
1451         call->enabled = 0;
1452         call->regfunc = probe_event_enable;
1453         call->unregfunc = probe_event_disable;
1454
1455 #ifdef CONFIG_EVENT_PROFILE
1456         atomic_set(&call->profile_count, -1);
1457         call->profile_enable = probe_profile_enable;
1458         call->profile_disable = probe_profile_disable;
1459 #endif
1460         call->data = tp;
1461         ret = trace_add_event_call(call);
1462         if (ret) {
1463                 pr_info("Failed to register kprobe event: %s\n", call->name);
1464                 unregister_ftrace_event(&tp->event);
1465         }
1466         return ret;
1467 }
1468
1469 static void unregister_probe_event(struct trace_probe *tp)
1470 {
1471         /* tp->event is unregistered in trace_remove_event_call() */
1472         trace_remove_event_call(&tp->call);
1473 }
1474
1475 /* Make a debugfs interface for controling probe points */
1476 static __init int init_kprobe_trace(void)
1477 {
1478         struct dentry *d_tracer;
1479         struct dentry *entry;
1480
1481         d_tracer = tracing_init_dentry();
1482         if (!d_tracer)
1483                 return 0;
1484
1485         entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
1486                                     NULL, &kprobe_events_ops);
1487
1488         /* Event list interface */
1489         if (!entry)
1490                 pr_warning("Could not create debugfs "
1491                            "'kprobe_events' entry\n");
1492
1493         /* Profile interface */
1494         entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
1495                                     NULL, &kprobe_profile_ops);
1496
1497         if (!entry)
1498                 pr_warning("Could not create debugfs "
1499                            "'kprobe_profile' entry\n");
1500         return 0;
1501 }
1502 fs_initcall(init_kprobe_trace);
1503
1504
1505 #ifdef CONFIG_FTRACE_STARTUP_TEST
1506
1507 static int kprobe_trace_selftest_target(int a1, int a2, int a3,
1508                                         int a4, int a5, int a6)
1509 {
1510         return a1 + a2 + a3 + a4 + a5 + a6;
1511 }
1512
1513 static __init int kprobe_trace_self_tests_init(void)
1514 {
1515         int ret;
1516         int (*target)(int, int, int, int, int, int);
1517
1518         target = kprobe_trace_selftest_target;
1519
1520         pr_info("Testing kprobe tracing: ");
1521
1522         ret = command_trace_probe("p:testprobe kprobe_trace_selftest_target "
1523                                   "$arg1 $arg2 $arg3 $arg4 $stack $stack0");
1524         if (WARN_ON_ONCE(ret))
1525                 pr_warning("error enabling function entry\n");
1526
1527         ret = command_trace_probe("r:testprobe2 kprobe_trace_selftest_target "
1528                                   "$retval");
1529         if (WARN_ON_ONCE(ret))
1530                 pr_warning("error enabling function return\n");
1531
1532         ret = target(1, 2, 3, 4, 5, 6);
1533
1534         cleanup_all_probes();
1535
1536         pr_cont("OK\n");
1537         return 0;
1538 }
1539
1540 late_initcall(kprobe_trace_self_tests_init);
1541
1542 #endif