Merge branch 'tip/perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt...
[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 #include <linux/stringify.h>
33 #include <linux/limits.h>
34 #include <asm/bitsperlong.h>
35
36 #include "trace.h"
37 #include "trace_output.h"
38
39 #define MAX_TRACE_ARGS 128
40 #define MAX_ARGSTR_LEN 63
41 #define MAX_EVENT_NAME_LEN 64
42 #define MAX_STRING_SIZE PATH_MAX
43 #define KPROBE_EVENT_SYSTEM "kprobes"
44
45 /* Reserved field names */
46 #define FIELD_STRING_IP "__probe_ip"
47 #define FIELD_STRING_RETIP "__probe_ret_ip"
48 #define FIELD_STRING_FUNC "__probe_func"
49
50 const char *reserved_field_names[] = {
51         "common_type",
52         "common_flags",
53         "common_preempt_count",
54         "common_pid",
55         "common_tgid",
56         "common_lock_depth",
57         FIELD_STRING_IP,
58         FIELD_STRING_RETIP,
59         FIELD_STRING_FUNC,
60 };
61
62 /* Printing function type */
63 typedef int (*print_type_func_t)(struct trace_seq *, const char *, void *,
64                                  void *);
65 #define PRINT_TYPE_FUNC_NAME(type)      print_type_##type
66 #define PRINT_TYPE_FMT_NAME(type)       print_type_format_##type
67
68 /* Printing  in basic type function template */
69 #define DEFINE_BASIC_PRINT_TYPE_FUNC(type, fmt, cast)                   \
70 static __kprobes int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s,    \
71                                                 const char *name,       \
72                                                 void *data, void *ent)\
73 {                                                                       \
74         return trace_seq_printf(s, " %s=" fmt, name, (cast)*(type *)data);\
75 }                                                                       \
76 static const char PRINT_TYPE_FMT_NAME(type)[] = fmt;
77
78 DEFINE_BASIC_PRINT_TYPE_FUNC(u8, "%x", unsigned int)
79 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, "%x", unsigned int)
80 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, "%lx", unsigned long)
81 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, "%llx", unsigned long long)
82 DEFINE_BASIC_PRINT_TYPE_FUNC(s8, "%d", int)
83 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, "%d", int)
84 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, "%ld", long)
85 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, "%lld", long long)
86
87 /* data_rloc: data relative location, compatible with u32 */
88 #define make_data_rloc(len, roffs)      \
89         (((u32)(len) << 16) | ((u32)(roffs) & 0xffff))
90 #define get_rloc_len(dl)        ((u32)(dl) >> 16)
91 #define get_rloc_offs(dl)       ((u32)(dl) & 0xffff)
92
93 static inline void *get_rloc_data(u32 *dl)
94 {
95         return (u8 *)dl + get_rloc_offs(*dl);
96 }
97
98 /* For data_loc conversion */
99 static inline void *get_loc_data(u32 *dl, void *ent)
100 {
101         return (u8 *)ent + get_rloc_offs(*dl);
102 }
103
104 /*
105  * Convert data_rloc to data_loc:
106  *  data_rloc stores the offset from data_rloc itself, but data_loc
107  *  stores the offset from event entry.
108  */
109 #define convert_rloc_to_loc(dl, offs)   ((u32)(dl) + (offs))
110
111 /* For defining macros, define string/string_size types */
112 typedef u32 string;
113 typedef u32 string_size;
114
115 /* Print type function for string type */
116 static __kprobes int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s,
117                                                   const char *name,
118                                                   void *data, void *ent)
119 {
120         int len = *(u32 *)data >> 16;
121
122         if (!len)
123                 return trace_seq_printf(s, " %s=(fault)", name);
124         else
125                 return trace_seq_printf(s, " %s=\"%s\"", name,
126                                         (const char *)get_loc_data(data, ent));
127 }
128 static const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
129
130 /* Data fetch function type */
131 typedef void (*fetch_func_t)(struct pt_regs *, void *, void *);
132
133 struct fetch_param {
134         fetch_func_t    fn;
135         void *data;
136 };
137
138 static __kprobes void call_fetch(struct fetch_param *fprm,
139                                  struct pt_regs *regs, void *dest)
140 {
141         return fprm->fn(regs, fprm->data, dest);
142 }
143
144 #define FETCH_FUNC_NAME(method, type)   fetch_##method##_##type
145 /*
146  * Define macro for basic types - we don't need to define s* types, because
147  * we have to care only about bitwidth at recording time.
148  */
149 #define DEFINE_BASIC_FETCH_FUNCS(method) \
150 DEFINE_FETCH_##method(u8)               \
151 DEFINE_FETCH_##method(u16)              \
152 DEFINE_FETCH_##method(u32)              \
153 DEFINE_FETCH_##method(u64)
154
155 #define CHECK_FETCH_FUNCS(method, fn)                   \
156         (((FETCH_FUNC_NAME(method, u8) == fn) ||        \
157           (FETCH_FUNC_NAME(method, u16) == fn) ||       \
158           (FETCH_FUNC_NAME(method, u32) == fn) ||       \
159           (FETCH_FUNC_NAME(method, u64) == fn) ||       \
160           (FETCH_FUNC_NAME(method, string) == fn) ||    \
161           (FETCH_FUNC_NAME(method, string_size) == fn)) \
162          && (fn != NULL))
163
164 /* Data fetch function templates */
165 #define DEFINE_FETCH_reg(type)                                          \
166 static __kprobes void FETCH_FUNC_NAME(reg, type)(struct pt_regs *regs,  \
167                                         void *offset, void *dest)       \
168 {                                                                       \
169         *(type *)dest = (type)regs_get_register(regs,                   \
170                                 (unsigned int)((unsigned long)offset)); \
171 }
172 DEFINE_BASIC_FETCH_FUNCS(reg)
173 /* No string on the register */
174 #define fetch_reg_string NULL
175 #define fetch_reg_string_size NULL
176
177 #define DEFINE_FETCH_stack(type)                                        \
178 static __kprobes void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,\
179                                           void *offset, void *dest)     \
180 {                                                                       \
181         *(type *)dest = (type)regs_get_kernel_stack_nth(regs,           \
182                                 (unsigned int)((unsigned long)offset)); \
183 }
184 DEFINE_BASIC_FETCH_FUNCS(stack)
185 /* No string on the stack entry */
186 #define fetch_stack_string NULL
187 #define fetch_stack_string_size NULL
188
189 #define DEFINE_FETCH_retval(type)                                       \
190 static __kprobes void FETCH_FUNC_NAME(retval, type)(struct pt_regs *regs,\
191                                           void *dummy, void *dest)      \
192 {                                                                       \
193         *(type *)dest = (type)regs_return_value(regs);                  \
194 }
195 DEFINE_BASIC_FETCH_FUNCS(retval)
196 /* No string on the retval */
197 #define fetch_retval_string NULL
198 #define fetch_retval_string_size NULL
199
200 #define DEFINE_FETCH_memory(type)                                       \
201 static __kprobes void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,\
202                                           void *addr, void *dest)       \
203 {                                                                       \
204         type retval;                                                    \
205         if (probe_kernel_address(addr, retval))                         \
206                 *(type *)dest = 0;                                      \
207         else                                                            \
208                 *(type *)dest = retval;                                 \
209 }
210 DEFINE_BASIC_FETCH_FUNCS(memory)
211 /*
212  * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
213  * length and relative data location.
214  */
215 static __kprobes void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
216                                                       void *addr, void *dest)
217 {
218         long ret;
219         int maxlen = get_rloc_len(*(u32 *)dest);
220         u8 *dst = get_rloc_data(dest);
221         u8 *src = addr;
222         mm_segment_t old_fs = get_fs();
223         if (!maxlen)
224                 return;
225         /*
226          * Try to get string again, since the string can be changed while
227          * probing.
228          */
229         set_fs(KERNEL_DS);
230         pagefault_disable();
231         do
232                 ret = __copy_from_user_inatomic(dst++, src++, 1);
233         while (dst[-1] && ret == 0 && src - (u8 *)addr < maxlen);
234         dst[-1] = '\0';
235         pagefault_enable();
236         set_fs(old_fs);
237
238         if (ret < 0) {  /* Failed to fetch string */
239                 ((u8 *)get_rloc_data(dest))[0] = '\0';
240                 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
241         } else
242                 *(u32 *)dest = make_data_rloc(src - (u8 *)addr,
243                                               get_rloc_offs(*(u32 *)dest));
244 }
245 /* Return the length of string -- including null terminal byte */
246 static __kprobes void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
247                                                         void *addr, void *dest)
248 {
249         int ret, len = 0;
250         u8 c;
251         mm_segment_t old_fs = get_fs();
252
253         set_fs(KERNEL_DS);
254         pagefault_disable();
255         do {
256                 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
257                 len++;
258         } while (c && ret == 0 && len < MAX_STRING_SIZE);
259         pagefault_enable();
260         set_fs(old_fs);
261
262         if (ret < 0)    /* Failed to check the length */
263                 *(u32 *)dest = 0;
264         else
265                 *(u32 *)dest = len;
266 }
267
268 /* Memory fetching by symbol */
269 struct symbol_cache {
270         char *symbol;
271         long offset;
272         unsigned long addr;
273 };
274
275 static unsigned long update_symbol_cache(struct symbol_cache *sc)
276 {
277         sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
278         if (sc->addr)
279                 sc->addr += sc->offset;
280         return sc->addr;
281 }
282
283 static void free_symbol_cache(struct symbol_cache *sc)
284 {
285         kfree(sc->symbol);
286         kfree(sc);
287 }
288
289 static struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
290 {
291         struct symbol_cache *sc;
292
293         if (!sym || strlen(sym) == 0)
294                 return NULL;
295         sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
296         if (!sc)
297                 return NULL;
298
299         sc->symbol = kstrdup(sym, GFP_KERNEL);
300         if (!sc->symbol) {
301                 kfree(sc);
302                 return NULL;
303         }
304         sc->offset = offset;
305
306         update_symbol_cache(sc);
307         return sc;
308 }
309
310 #define DEFINE_FETCH_symbol(type)                                       \
311 static __kprobes void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs,\
312                                           void *data, void *dest)       \
313 {                                                                       \
314         struct symbol_cache *sc = data;                                 \
315         if (sc->addr)                                                   \
316                 fetch_memory_##type(regs, (void *)sc->addr, dest);      \
317         else                                                            \
318                 *(type *)dest = 0;                                      \
319 }
320 DEFINE_BASIC_FETCH_FUNCS(symbol)
321 DEFINE_FETCH_symbol(string)
322 DEFINE_FETCH_symbol(string_size)
323
324 /* Dereference memory access function */
325 struct deref_fetch_param {
326         struct fetch_param orig;
327         long offset;
328 };
329
330 #define DEFINE_FETCH_deref(type)                                        \
331 static __kprobes void FETCH_FUNC_NAME(deref, type)(struct pt_regs *regs,\
332                                             void *data, void *dest)     \
333 {                                                                       \
334         struct deref_fetch_param *dprm = data;                          \
335         unsigned long addr;                                             \
336         call_fetch(&dprm->orig, regs, &addr);                           \
337         if (addr) {                                                     \
338                 addr += dprm->offset;                                   \
339                 fetch_memory_##type(regs, (void *)addr, dest);          \
340         } else                                                          \
341                 *(type *)dest = 0;                                      \
342 }
343 DEFINE_BASIC_FETCH_FUNCS(deref)
344 DEFINE_FETCH_deref(string)
345 DEFINE_FETCH_deref(string_size)
346
347 static __kprobes void free_deref_fetch_param(struct deref_fetch_param *data)
348 {
349         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
350                 free_deref_fetch_param(data->orig.data);
351         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
352                 free_symbol_cache(data->orig.data);
353         kfree(data);
354 }
355
356 /* Bitfield fetch function */
357 struct bitfield_fetch_param {
358         struct fetch_param orig;
359         unsigned char hi_shift;
360         unsigned char low_shift;
361 };
362
363 #define DEFINE_FETCH_bitfield(type)                                     \
364 static __kprobes void FETCH_FUNC_NAME(bitfield, type)(struct pt_regs *regs,\
365                                             void *data, void *dest)     \
366 {                                                                       \
367         struct bitfield_fetch_param *bprm = data;                       \
368         type buf = 0;                                                   \
369         call_fetch(&bprm->orig, regs, &buf);                            \
370         if (buf) {                                                      \
371                 buf <<= bprm->hi_shift;                                 \
372                 buf >>= bprm->low_shift;                                \
373         }                                                               \
374         *(type *)dest = buf;                                            \
375 }
376 DEFINE_BASIC_FETCH_FUNCS(bitfield)
377 #define fetch_bitfield_string NULL
378 #define fetch_bitfield_string_size NULL
379
380 static __kprobes void
381 free_bitfield_fetch_param(struct bitfield_fetch_param *data)
382 {
383         /*
384          * Don't check the bitfield itself, because this must be the
385          * last fetch function.
386          */
387         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
388                 free_deref_fetch_param(data->orig.data);
389         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
390                 free_symbol_cache(data->orig.data);
391         kfree(data);
392 }
393 /* Default (unsigned long) fetch type */
394 #define __DEFAULT_FETCH_TYPE(t) u##t
395 #define _DEFAULT_FETCH_TYPE(t) __DEFAULT_FETCH_TYPE(t)
396 #define DEFAULT_FETCH_TYPE _DEFAULT_FETCH_TYPE(BITS_PER_LONG)
397 #define DEFAULT_FETCH_TYPE_STR __stringify(DEFAULT_FETCH_TYPE)
398
399 /* Fetch types */
400 enum {
401         FETCH_MTD_reg = 0,
402         FETCH_MTD_stack,
403         FETCH_MTD_retval,
404         FETCH_MTD_memory,
405         FETCH_MTD_symbol,
406         FETCH_MTD_deref,
407         FETCH_MTD_bitfield,
408         FETCH_MTD_END,
409 };
410
411 #define ASSIGN_FETCH_FUNC(method, type) \
412         [FETCH_MTD_##method] = FETCH_FUNC_NAME(method, type)
413
414 #define __ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, _fmttype) \
415         {.name = _name,                         \
416          .size = _size,                                 \
417          .is_signed = sign,                             \
418          .print = PRINT_TYPE_FUNC_NAME(ptype),          \
419          .fmt = PRINT_TYPE_FMT_NAME(ptype),             \
420          .fmttype = _fmttype,                           \
421          .fetch = {                                     \
422 ASSIGN_FETCH_FUNC(reg, ftype),                          \
423 ASSIGN_FETCH_FUNC(stack, ftype),                        \
424 ASSIGN_FETCH_FUNC(retval, ftype),                       \
425 ASSIGN_FETCH_FUNC(memory, ftype),                       \
426 ASSIGN_FETCH_FUNC(symbol, ftype),                       \
427 ASSIGN_FETCH_FUNC(deref, ftype),                        \
428 ASSIGN_FETCH_FUNC(bitfield, ftype),                     \
429           }                                             \
430         }
431
432 #define ASSIGN_FETCH_TYPE(ptype, ftype, sign)                   \
433         __ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #ptype)
434
435 #define FETCH_TYPE_STRING 0
436 #define FETCH_TYPE_STRSIZE 1
437
438 /* Fetch type information table */
439 static const struct fetch_type {
440         const char      *name;          /* Name of type */
441         size_t          size;           /* Byte size of type */
442         int             is_signed;      /* Signed flag */
443         print_type_func_t       print;  /* Print functions */
444         const char      *fmt;           /* Fromat string */
445         const char      *fmttype;       /* Name in format file */
446         /* Fetch functions */
447         fetch_func_t    fetch[FETCH_MTD_END];
448 } fetch_type_table[] = {
449         /* Special types */
450         [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
451                                         sizeof(u32), 1, "__data_loc char[]"),
452         [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
453                                         string_size, sizeof(u32), 0, "u32"),
454         /* Basic types */
455         ASSIGN_FETCH_TYPE(u8,  u8,  0),
456         ASSIGN_FETCH_TYPE(u16, u16, 0),
457         ASSIGN_FETCH_TYPE(u32, u32, 0),
458         ASSIGN_FETCH_TYPE(u64, u64, 0),
459         ASSIGN_FETCH_TYPE(s8,  u8,  1),
460         ASSIGN_FETCH_TYPE(s16, u16, 1),
461         ASSIGN_FETCH_TYPE(s32, u32, 1),
462         ASSIGN_FETCH_TYPE(s64, u64, 1),
463 };
464
465 static const struct fetch_type *find_fetch_type(const char *type)
466 {
467         int i;
468
469         if (!type)
470                 type = DEFAULT_FETCH_TYPE_STR;
471
472         /* Special case: bitfield */
473         if (*type == 'b') {
474                 unsigned long bs;
475                 type = strchr(type, '/');
476                 if (!type)
477                         goto fail;
478                 type++;
479                 if (strict_strtoul(type, 0, &bs))
480                         goto fail;
481                 switch (bs) {
482                 case 8:
483                         return find_fetch_type("u8");
484                 case 16:
485                         return find_fetch_type("u16");
486                 case 32:
487                         return find_fetch_type("u32");
488                 case 64:
489                         return find_fetch_type("u64");
490                 default:
491                         goto fail;
492                 }
493         }
494
495         for (i = 0; i < ARRAY_SIZE(fetch_type_table); i++)
496                 if (strcmp(type, fetch_type_table[i].name) == 0)
497                         return &fetch_type_table[i];
498 fail:
499         return NULL;
500 }
501
502 /* Special function : only accept unsigned long */
503 static __kprobes void fetch_stack_address(struct pt_regs *regs,
504                                           void *dummy, void *dest)
505 {
506         *(unsigned long *)dest = kernel_stack_pointer(regs);
507 }
508
509 static fetch_func_t get_fetch_size_function(const struct fetch_type *type,
510                                             fetch_func_t orig_fn)
511 {
512         int i;
513
514         if (type != &fetch_type_table[FETCH_TYPE_STRING])
515                 return NULL;    /* Only string type needs size function */
516         for (i = 0; i < FETCH_MTD_END; i++)
517                 if (type->fetch[i] == orig_fn)
518                         return fetch_type_table[FETCH_TYPE_STRSIZE].fetch[i];
519
520         WARN_ON(1);     /* This should not happen */
521         return NULL;
522 }
523
524 /**
525  * Kprobe event core functions
526  */
527
528 struct probe_arg {
529         struct fetch_param      fetch;
530         struct fetch_param      fetch_size;
531         unsigned int            offset; /* Offset from argument entry */
532         const char              *name;  /* Name of this argument */
533         const char              *comm;  /* Command of this argument */
534         const struct fetch_type *type;  /* Type of this argument */
535 };
536
537 /* Flags for trace_probe */
538 #define TP_FLAG_TRACE   1
539 #define TP_FLAG_PROFILE 2
540
541 struct trace_probe {
542         struct list_head        list;
543         struct kretprobe        rp;     /* Use rp.kp for kprobe use */
544         unsigned long           nhit;
545         unsigned int            flags;  /* For TP_FLAG_* */
546         const char              *symbol;        /* symbol name */
547         struct ftrace_event_class       class;
548         struct ftrace_event_call        call;
549         ssize_t                 size;           /* trace entry size */
550         unsigned int            nr_args;
551         struct probe_arg        args[];
552 };
553
554 #define SIZEOF_TRACE_PROBE(n)                   \
555         (offsetof(struct trace_probe, args) +   \
556         (sizeof(struct probe_arg) * (n)))
557
558
559 static __kprobes int probe_is_return(struct trace_probe *tp)
560 {
561         return tp->rp.handler != NULL;
562 }
563
564 static __kprobes const char *probe_symbol(struct trace_probe *tp)
565 {
566         return tp->symbol ? tp->symbol : "unknown";
567 }
568
569 static int register_probe_event(struct trace_probe *tp);
570 static void unregister_probe_event(struct trace_probe *tp);
571
572 static DEFINE_MUTEX(probe_lock);
573 static LIST_HEAD(probe_list);
574
575 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
576 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
577                                 struct pt_regs *regs);
578
579 /* Check the name is good for event/group/fields */
580 static int is_good_name(const char *name)
581 {
582         if (!isalpha(*name) && *name != '_')
583                 return 0;
584         while (*++name != '\0') {
585                 if (!isalpha(*name) && !isdigit(*name) && *name != '_')
586                         return 0;
587         }
588         return 1;
589 }
590
591 /*
592  * Allocate new trace_probe and initialize it (including kprobes).
593  */
594 static struct trace_probe *alloc_trace_probe(const char *group,
595                                              const char *event,
596                                              void *addr,
597                                              const char *symbol,
598                                              unsigned long offs,
599                                              int nargs, int is_return)
600 {
601         struct trace_probe *tp;
602         int ret = -ENOMEM;
603
604         tp = kzalloc(SIZEOF_TRACE_PROBE(nargs), GFP_KERNEL);
605         if (!tp)
606                 return ERR_PTR(ret);
607
608         if (symbol) {
609                 tp->symbol = kstrdup(symbol, GFP_KERNEL);
610                 if (!tp->symbol)
611                         goto error;
612                 tp->rp.kp.symbol_name = tp->symbol;
613                 tp->rp.kp.offset = offs;
614         } else
615                 tp->rp.kp.addr = addr;
616
617         if (is_return)
618                 tp->rp.handler = kretprobe_dispatcher;
619         else
620                 tp->rp.kp.pre_handler = kprobe_dispatcher;
621
622         if (!event || !is_good_name(event)) {
623                 ret = -EINVAL;
624                 goto error;
625         }
626
627         tp->call.class = &tp->class;
628         tp->call.name = kstrdup(event, GFP_KERNEL);
629         if (!tp->call.name)
630                 goto error;
631
632         if (!group || !is_good_name(group)) {
633                 ret = -EINVAL;
634                 goto error;
635         }
636
637         tp->class.system = kstrdup(group, GFP_KERNEL);
638         if (!tp->class.system)
639                 goto error;
640
641         INIT_LIST_HEAD(&tp->list);
642         return tp;
643 error:
644         kfree(tp->call.name);
645         kfree(tp->symbol);
646         kfree(tp);
647         return ERR_PTR(ret);
648 }
649
650 static void free_probe_arg(struct probe_arg *arg)
651 {
652         if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
653                 free_bitfield_fetch_param(arg->fetch.data);
654         else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
655                 free_deref_fetch_param(arg->fetch.data);
656         else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
657                 free_symbol_cache(arg->fetch.data);
658         kfree(arg->name);
659         kfree(arg->comm);
660 }
661
662 static void free_trace_probe(struct trace_probe *tp)
663 {
664         int i;
665
666         for (i = 0; i < tp->nr_args; i++)
667                 free_probe_arg(&tp->args[i]);
668
669         kfree(tp->call.class->system);
670         kfree(tp->call.name);
671         kfree(tp->symbol);
672         kfree(tp);
673 }
674
675 static struct trace_probe *find_probe_event(const char *event,
676                                             const char *group)
677 {
678         struct trace_probe *tp;
679
680         list_for_each_entry(tp, &probe_list, list)
681                 if (strcmp(tp->call.name, event) == 0 &&
682                     strcmp(tp->call.class->system, group) == 0)
683                         return tp;
684         return NULL;
685 }
686
687 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
688 static void unregister_trace_probe(struct trace_probe *tp)
689 {
690         if (probe_is_return(tp))
691                 unregister_kretprobe(&tp->rp);
692         else
693                 unregister_kprobe(&tp->rp.kp);
694         list_del(&tp->list);
695         unregister_probe_event(tp);
696 }
697
698 /* Register a trace_probe and probe_event */
699 static int register_trace_probe(struct trace_probe *tp)
700 {
701         struct trace_probe *old_tp;
702         int ret;
703
704         mutex_lock(&probe_lock);
705
706         /* register as an event */
707         old_tp = find_probe_event(tp->call.name, tp->call.class->system);
708         if (old_tp) {
709                 /* delete old event */
710                 unregister_trace_probe(old_tp);
711                 free_trace_probe(old_tp);
712         }
713         ret = register_probe_event(tp);
714         if (ret) {
715                 pr_warning("Failed to register probe event(%d)\n", ret);
716                 goto end;
717         }
718
719         tp->rp.kp.flags |= KPROBE_FLAG_DISABLED;
720         if (probe_is_return(tp))
721                 ret = register_kretprobe(&tp->rp);
722         else
723                 ret = register_kprobe(&tp->rp.kp);
724
725         if (ret) {
726                 pr_warning("Could not insert probe(%d)\n", ret);
727                 if (ret == -EILSEQ) {
728                         pr_warning("Probing address(0x%p) is not an "
729                                    "instruction boundary.\n",
730                                    tp->rp.kp.addr);
731                         ret = -EINVAL;
732                 }
733                 unregister_probe_event(tp);
734         } else
735                 list_add_tail(&tp->list, &probe_list);
736 end:
737         mutex_unlock(&probe_lock);
738         return ret;
739 }
740
741 /* Split symbol and offset. */
742 static int split_symbol_offset(char *symbol, unsigned long *offset)
743 {
744         char *tmp;
745         int ret;
746
747         if (!offset)
748                 return -EINVAL;
749
750         tmp = strchr(symbol, '+');
751         if (tmp) {
752                 /* skip sign because strict_strtol doesn't accept '+' */
753                 ret = strict_strtoul(tmp + 1, 0, offset);
754                 if (ret)
755                         return ret;
756                 *tmp = '\0';
757         } else
758                 *offset = 0;
759         return 0;
760 }
761
762 #define PARAM_MAX_ARGS 16
763 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
764
765 static int parse_probe_vars(char *arg, const struct fetch_type *t,
766                             struct fetch_param *f, int is_return)
767 {
768         int ret = 0;
769         unsigned long param;
770
771         if (strcmp(arg, "retval") == 0) {
772                 if (is_return)
773                         f->fn = t->fetch[FETCH_MTD_retval];
774                 else
775                         ret = -EINVAL;
776         } else if (strncmp(arg, "stack", 5) == 0) {
777                 if (arg[5] == '\0') {
778                         if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR) == 0)
779                                 f->fn = fetch_stack_address;
780                         else
781                                 ret = -EINVAL;
782                 } else if (isdigit(arg[5])) {
783                         ret = strict_strtoul(arg + 5, 10, &param);
784                         if (ret || param > PARAM_MAX_STACK)
785                                 ret = -EINVAL;
786                         else {
787                                 f->fn = t->fetch[FETCH_MTD_stack];
788                                 f->data = (void *)param;
789                         }
790                 } else
791                         ret = -EINVAL;
792         } else
793                 ret = -EINVAL;
794         return ret;
795 }
796
797 /* Recursive argument parser */
798 static int __parse_probe_arg(char *arg, const struct fetch_type *t,
799                              struct fetch_param *f, int is_return)
800 {
801         int ret = 0;
802         unsigned long param;
803         long offset;
804         char *tmp;
805
806         switch (arg[0]) {
807         case '$':
808                 ret = parse_probe_vars(arg + 1, t, f, is_return);
809                 break;
810         case '%':       /* named register */
811                 ret = regs_query_register_offset(arg + 1);
812                 if (ret >= 0) {
813                         f->fn = t->fetch[FETCH_MTD_reg];
814                         f->data = (void *)(unsigned long)ret;
815                         ret = 0;
816                 }
817                 break;
818         case '@':       /* memory or symbol */
819                 if (isdigit(arg[1])) {
820                         ret = strict_strtoul(arg + 1, 0, &param);
821                         if (ret)
822                                 break;
823                         f->fn = t->fetch[FETCH_MTD_memory];
824                         f->data = (void *)param;
825                 } else {
826                         ret = split_symbol_offset(arg + 1, &offset);
827                         if (ret)
828                                 break;
829                         f->data = alloc_symbol_cache(arg + 1, offset);
830                         if (f->data)
831                                 f->fn = t->fetch[FETCH_MTD_symbol];
832                 }
833                 break;
834         case '+':       /* deref memory */
835                 arg++;  /* Skip '+', because strict_strtol() rejects it. */
836         case '-':
837                 tmp = strchr(arg, '(');
838                 if (!tmp)
839                         break;
840                 *tmp = '\0';
841                 ret = strict_strtol(arg, 0, &offset);
842                 if (ret)
843                         break;
844                 arg = tmp + 1;
845                 tmp = strrchr(arg, ')');
846                 if (tmp) {
847                         struct deref_fetch_param *dprm;
848                         const struct fetch_type *t2 = find_fetch_type(NULL);
849                         *tmp = '\0';
850                         dprm = kzalloc(sizeof(struct deref_fetch_param),
851                                        GFP_KERNEL);
852                         if (!dprm)
853                                 return -ENOMEM;
854                         dprm->offset = offset;
855                         ret = __parse_probe_arg(arg, t2, &dprm->orig,
856                                                 is_return);
857                         if (ret)
858                                 kfree(dprm);
859                         else {
860                                 f->fn = t->fetch[FETCH_MTD_deref];
861                                 f->data = (void *)dprm;
862                         }
863                 }
864                 break;
865         }
866         if (!ret && !f->fn) {   /* Parsed, but do not find fetch method */
867                 pr_info("%s type has no corresponding fetch method.\n",
868                         t->name);
869                 ret = -EINVAL;
870         }
871         return ret;
872 }
873
874 #define BYTES_TO_BITS(nb)       ((BITS_PER_LONG * (nb)) / sizeof(long))
875
876 /* Bitfield type needs to be parsed into a fetch function */
877 static int __parse_bitfield_probe_arg(const char *bf,
878                                       const struct fetch_type *t,
879                                       struct fetch_param *f)
880 {
881         struct bitfield_fetch_param *bprm;
882         unsigned long bw, bo;
883         char *tail;
884
885         if (*bf != 'b')
886                 return 0;
887
888         bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
889         if (!bprm)
890                 return -ENOMEM;
891         bprm->orig = *f;
892         f->fn = t->fetch[FETCH_MTD_bitfield];
893         f->data = (void *)bprm;
894
895         bw = simple_strtoul(bf + 1, &tail, 0);  /* Use simple one */
896         if (bw == 0 || *tail != '@')
897                 return -EINVAL;
898
899         bf = tail + 1;
900         bo = simple_strtoul(bf, &tail, 0);
901         if (tail == bf || *tail != '/')
902                 return -EINVAL;
903
904         bprm->hi_shift = BYTES_TO_BITS(t->size) - (bw + bo);
905         bprm->low_shift = bprm->hi_shift + bo;
906         return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
907 }
908
909 /* String length checking wrapper */
910 static int parse_probe_arg(char *arg, struct trace_probe *tp,
911                            struct probe_arg *parg, int is_return)
912 {
913         const char *t;
914         int ret;
915
916         if (strlen(arg) > MAX_ARGSTR_LEN) {
917                 pr_info("Argument is too long.: %s\n",  arg);
918                 return -ENOSPC;
919         }
920         parg->comm = kstrdup(arg, GFP_KERNEL);
921         if (!parg->comm) {
922                 pr_info("Failed to allocate memory for command '%s'.\n", arg);
923                 return -ENOMEM;
924         }
925         t = strchr(parg->comm, ':');
926         if (t) {
927                 arg[t - parg->comm] = '\0';
928                 t++;
929         }
930         parg->type = find_fetch_type(t);
931         if (!parg->type) {
932                 pr_info("Unsupported type: %s\n", t);
933                 return -EINVAL;
934         }
935         parg->offset = tp->size;
936         tp->size += parg->type->size;
937         ret = __parse_probe_arg(arg, parg->type, &parg->fetch, is_return);
938         if (ret >= 0 && t != NULL)
939                 ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
940         if (ret >= 0) {
941                 parg->fetch_size.fn = get_fetch_size_function(parg->type,
942                                                               parg->fetch.fn);
943                 parg->fetch_size.data = parg->fetch.data;
944         }
945         return ret;
946 }
947
948 /* Return 1 if name is reserved or already used by another argument */
949 static int conflict_field_name(const char *name,
950                                struct probe_arg *args, int narg)
951 {
952         int i;
953         for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
954                 if (strcmp(reserved_field_names[i], name) == 0)
955                         return 1;
956         for (i = 0; i < narg; i++)
957                 if (strcmp(args[i].name, name) == 0)
958                         return 1;
959         return 0;
960 }
961
962 static int create_trace_probe(int argc, char **argv)
963 {
964         /*
965          * Argument syntax:
966          *  - Add kprobe: p[:[GRP/]EVENT] KSYM[+OFFS]|KADDR [FETCHARGS]
967          *  - Add kretprobe: r[:[GRP/]EVENT] KSYM[+0] [FETCHARGS]
968          * Fetch args:
969          *  $retval     : fetch return value
970          *  $stack      : fetch stack address
971          *  $stackN     : fetch Nth of stack (N:0-)
972          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
973          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
974          *  %REG        : fetch register REG
975          * Dereferencing memory fetch:
976          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
977          * Alias name of args:
978          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
979          * Type of args:
980          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
981          */
982         struct trace_probe *tp;
983         int i, ret = 0;
984         int is_return = 0, is_delete = 0;
985         char *symbol = NULL, *event = NULL, *group = NULL;
986         char *arg;
987         unsigned long offset = 0;
988         void *addr = NULL;
989         char buf[MAX_EVENT_NAME_LEN];
990
991         /* argc must be >= 1 */
992         if (argv[0][0] == 'p')
993                 is_return = 0;
994         else if (argv[0][0] == 'r')
995                 is_return = 1;
996         else if (argv[0][0] == '-')
997                 is_delete = 1;
998         else {
999                 pr_info("Probe definition must be started with 'p', 'r' or"
1000                         " '-'.\n");
1001                 return -EINVAL;
1002         }
1003
1004         if (argv[0][1] == ':') {
1005                 event = &argv[0][2];
1006                 if (strchr(event, '/')) {
1007                         group = event;
1008                         event = strchr(group, '/') + 1;
1009                         event[-1] = '\0';
1010                         if (strlen(group) == 0) {
1011                                 pr_info("Group name is not specified\n");
1012                                 return -EINVAL;
1013                         }
1014                 }
1015                 if (strlen(event) == 0) {
1016                         pr_info("Event name is not specified\n");
1017                         return -EINVAL;
1018                 }
1019         }
1020         if (!group)
1021                 group = KPROBE_EVENT_SYSTEM;
1022
1023         if (is_delete) {
1024                 if (!event) {
1025                         pr_info("Delete command needs an event name.\n");
1026                         return -EINVAL;
1027                 }
1028                 mutex_lock(&probe_lock);
1029                 tp = find_probe_event(event, group);
1030                 if (!tp) {
1031                         mutex_unlock(&probe_lock);
1032                         pr_info("Event %s/%s doesn't exist.\n", group, event);
1033                         return -ENOENT;
1034                 }
1035                 /* delete an event */
1036                 unregister_trace_probe(tp);
1037                 free_trace_probe(tp);
1038                 mutex_unlock(&probe_lock);
1039                 return 0;
1040         }
1041
1042         if (argc < 2) {
1043                 pr_info("Probe point is not specified.\n");
1044                 return -EINVAL;
1045         }
1046         if (isdigit(argv[1][0])) {
1047                 if (is_return) {
1048                         pr_info("Return probe point must be a symbol.\n");
1049                         return -EINVAL;
1050                 }
1051                 /* an address specified */
1052                 ret = strict_strtoul(&argv[1][0], 0, (unsigned long *)&addr);
1053                 if (ret) {
1054                         pr_info("Failed to parse address.\n");
1055                         return ret;
1056                 }
1057         } else {
1058                 /* a symbol specified */
1059                 symbol = argv[1];
1060                 /* TODO: support .init module functions */
1061                 ret = split_symbol_offset(symbol, &offset);
1062                 if (ret) {
1063                         pr_info("Failed to parse symbol.\n");
1064                         return ret;
1065                 }
1066                 if (offset && is_return) {
1067                         pr_info("Return probe must be used without offset.\n");
1068                         return -EINVAL;
1069                 }
1070         }
1071         argc -= 2; argv += 2;
1072
1073         /* setup a probe */
1074         if (!event) {
1075                 /* Make a new event name */
1076                 if (symbol)
1077                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
1078                                  is_return ? 'r' : 'p', symbol, offset);
1079                 else
1080                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
1081                                  is_return ? 'r' : 'p', addr);
1082                 event = buf;
1083         }
1084         tp = alloc_trace_probe(group, event, addr, symbol, offset, argc,
1085                                is_return);
1086         if (IS_ERR(tp)) {
1087                 pr_info("Failed to allocate trace_probe.(%d)\n",
1088                         (int)PTR_ERR(tp));
1089                 return PTR_ERR(tp);
1090         }
1091
1092         /* parse arguments */
1093         ret = 0;
1094         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
1095                 /* Increment count for freeing args in error case */
1096                 tp->nr_args++;
1097
1098                 /* Parse argument name */
1099                 arg = strchr(argv[i], '=');
1100                 if (arg) {
1101                         *arg++ = '\0';
1102                         tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
1103                 } else {
1104                         arg = argv[i];
1105                         /* If argument name is omitted, set "argN" */
1106                         snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
1107                         tp->args[i].name = kstrdup(buf, GFP_KERNEL);
1108                 }
1109
1110                 if (!tp->args[i].name) {
1111                         pr_info("Failed to allocate argument[%d] name.\n", i);
1112                         ret = -ENOMEM;
1113                         goto error;
1114                 }
1115
1116                 if (!is_good_name(tp->args[i].name)) {
1117                         pr_info("Invalid argument[%d] name: %s\n",
1118                                 i, tp->args[i].name);
1119                         ret = -EINVAL;
1120                         goto error;
1121                 }
1122
1123                 if (conflict_field_name(tp->args[i].name, tp->args, i)) {
1124                         pr_info("Argument[%d] name '%s' conflicts with "
1125                                 "another field.\n", i, argv[i]);
1126                         ret = -EINVAL;
1127                         goto error;
1128                 }
1129
1130                 /* Parse fetch argument */
1131                 ret = parse_probe_arg(arg, tp, &tp->args[i], is_return);
1132                 if (ret) {
1133                         pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
1134                         goto error;
1135                 }
1136         }
1137
1138         ret = register_trace_probe(tp);
1139         if (ret)
1140                 goto error;
1141         return 0;
1142
1143 error:
1144         free_trace_probe(tp);
1145         return ret;
1146 }
1147
1148 static void cleanup_all_probes(void)
1149 {
1150         struct trace_probe *tp;
1151
1152         mutex_lock(&probe_lock);
1153         /* TODO: Use batch unregistration */
1154         while (!list_empty(&probe_list)) {
1155                 tp = list_entry(probe_list.next, struct trace_probe, list);
1156                 unregister_trace_probe(tp);
1157                 free_trace_probe(tp);
1158         }
1159         mutex_unlock(&probe_lock);
1160 }
1161
1162
1163 /* Probes listing interfaces */
1164 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
1165 {
1166         mutex_lock(&probe_lock);
1167         return seq_list_start(&probe_list, *pos);
1168 }
1169
1170 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
1171 {
1172         return seq_list_next(v, &probe_list, pos);
1173 }
1174
1175 static void probes_seq_stop(struct seq_file *m, void *v)
1176 {
1177         mutex_unlock(&probe_lock);
1178 }
1179
1180 static int probes_seq_show(struct seq_file *m, void *v)
1181 {
1182         struct trace_probe *tp = v;
1183         int i;
1184
1185         seq_printf(m, "%c", probe_is_return(tp) ? 'r' : 'p');
1186         seq_printf(m, ":%s/%s", tp->call.class->system, tp->call.name);
1187
1188         if (!tp->symbol)
1189                 seq_printf(m, " 0x%p", tp->rp.kp.addr);
1190         else if (tp->rp.kp.offset)
1191                 seq_printf(m, " %s+%u", probe_symbol(tp), tp->rp.kp.offset);
1192         else
1193                 seq_printf(m, " %s", probe_symbol(tp));
1194
1195         for (i = 0; i < tp->nr_args; i++)
1196                 seq_printf(m, " %s=%s", tp->args[i].name, tp->args[i].comm);
1197         seq_printf(m, "\n");
1198
1199         return 0;
1200 }
1201
1202 static const struct seq_operations probes_seq_op = {
1203         .start  = probes_seq_start,
1204         .next   = probes_seq_next,
1205         .stop   = probes_seq_stop,
1206         .show   = probes_seq_show
1207 };
1208
1209 static int probes_open(struct inode *inode, struct file *file)
1210 {
1211         if ((file->f_mode & FMODE_WRITE) &&
1212             (file->f_flags & O_TRUNC))
1213                 cleanup_all_probes();
1214
1215         return seq_open(file, &probes_seq_op);
1216 }
1217
1218 static int command_trace_probe(const char *buf)
1219 {
1220         char **argv;
1221         int argc = 0, ret = 0;
1222
1223         argv = argv_split(GFP_KERNEL, buf, &argc);
1224         if (!argv)
1225                 return -ENOMEM;
1226
1227         if (argc)
1228                 ret = create_trace_probe(argc, argv);
1229
1230         argv_free(argv);
1231         return ret;
1232 }
1233
1234 #define WRITE_BUFSIZE 4096
1235
1236 static ssize_t probes_write(struct file *file, const char __user *buffer,
1237                             size_t count, loff_t *ppos)
1238 {
1239         char *kbuf, *tmp;
1240         int ret;
1241         size_t done;
1242         size_t size;
1243
1244         kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
1245         if (!kbuf)
1246                 return -ENOMEM;
1247
1248         ret = done = 0;
1249         while (done < count) {
1250                 size = count - done;
1251                 if (size >= WRITE_BUFSIZE)
1252                         size = WRITE_BUFSIZE - 1;
1253                 if (copy_from_user(kbuf, buffer + done, size)) {
1254                         ret = -EFAULT;
1255                         goto out;
1256                 }
1257                 kbuf[size] = '\0';
1258                 tmp = strchr(kbuf, '\n');
1259                 if (tmp) {
1260                         *tmp = '\0';
1261                         size = tmp - kbuf + 1;
1262                 } else if (done + size < count) {
1263                         pr_warning("Line length is too long: "
1264                                    "Should be less than %d.", WRITE_BUFSIZE);
1265                         ret = -EINVAL;
1266                         goto out;
1267                 }
1268                 done += size;
1269                 /* Remove comments */
1270                 tmp = strchr(kbuf, '#');
1271                 if (tmp)
1272                         *tmp = '\0';
1273
1274                 ret = command_trace_probe(kbuf);
1275                 if (ret)
1276                         goto out;
1277         }
1278         ret = done;
1279 out:
1280         kfree(kbuf);
1281         return ret;
1282 }
1283
1284 static const struct file_operations kprobe_events_ops = {
1285         .owner          = THIS_MODULE,
1286         .open           = probes_open,
1287         .read           = seq_read,
1288         .llseek         = seq_lseek,
1289         .release        = seq_release,
1290         .write          = probes_write,
1291 };
1292
1293 /* Probes profiling interfaces */
1294 static int probes_profile_seq_show(struct seq_file *m, void *v)
1295 {
1296         struct trace_probe *tp = v;
1297
1298         seq_printf(m, "  %-44s %15lu %15lu\n", tp->call.name, tp->nhit,
1299                    tp->rp.kp.nmissed);
1300
1301         return 0;
1302 }
1303
1304 static const struct seq_operations profile_seq_op = {
1305         .start  = probes_seq_start,
1306         .next   = probes_seq_next,
1307         .stop   = probes_seq_stop,
1308         .show   = probes_profile_seq_show
1309 };
1310
1311 static int profile_open(struct inode *inode, struct file *file)
1312 {
1313         return seq_open(file, &profile_seq_op);
1314 }
1315
1316 static const struct file_operations kprobe_profile_ops = {
1317         .owner          = THIS_MODULE,
1318         .open           = profile_open,
1319         .read           = seq_read,
1320         .llseek         = seq_lseek,
1321         .release        = seq_release,
1322 };
1323
1324 /* Sum up total data length for dynamic arraies (strings) */
1325 static __kprobes int __get_data_size(struct trace_probe *tp,
1326                                      struct pt_regs *regs)
1327 {
1328         int i, ret = 0;
1329         u32 len;
1330
1331         for (i = 0; i < tp->nr_args; i++)
1332                 if (unlikely(tp->args[i].fetch_size.fn)) {
1333                         call_fetch(&tp->args[i].fetch_size, regs, &len);
1334                         ret += len;
1335                 }
1336
1337         return ret;
1338 }
1339
1340 /* Store the value of each argument */
1341 static __kprobes void store_trace_args(int ent_size, struct trace_probe *tp,
1342                                        struct pt_regs *regs,
1343                                        u8 *data, int maxlen)
1344 {
1345         int i;
1346         u32 end = tp->size;
1347         u32 *dl;        /* Data (relative) location */
1348
1349         for (i = 0; i < tp->nr_args; i++) {
1350                 if (unlikely(tp->args[i].fetch_size.fn)) {
1351                         /*
1352                          * First, we set the relative location and
1353                          * maximum data length to *dl
1354                          */
1355                         dl = (u32 *)(data + tp->args[i].offset);
1356                         *dl = make_data_rloc(maxlen, end - tp->args[i].offset);
1357                         /* Then try to fetch string or dynamic array data */
1358                         call_fetch(&tp->args[i].fetch, regs, dl);
1359                         /* Reduce maximum length */
1360                         end += get_rloc_len(*dl);
1361                         maxlen -= get_rloc_len(*dl);
1362                         /* Trick here, convert data_rloc to data_loc */
1363                         *dl = convert_rloc_to_loc(*dl,
1364                                  ent_size + tp->args[i].offset);
1365                 } else
1366                         /* Just fetching data normally */
1367                         call_fetch(&tp->args[i].fetch, regs,
1368                                    data + tp->args[i].offset);
1369         }
1370 }
1371
1372 /* Kprobe handler */
1373 static __kprobes void kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
1374 {
1375         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1376         struct kprobe_trace_entry_head *entry;
1377         struct ring_buffer_event *event;
1378         struct ring_buffer *buffer;
1379         int size, dsize, pc;
1380         unsigned long irq_flags;
1381         struct ftrace_event_call *call = &tp->call;
1382
1383         tp->nhit++;
1384
1385         local_save_flags(irq_flags);
1386         pc = preempt_count();
1387
1388         dsize = __get_data_size(tp, regs);
1389         size = sizeof(*entry) + tp->size + dsize;
1390
1391         event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
1392                                                   size, irq_flags, pc);
1393         if (!event)
1394                 return;
1395
1396         entry = ring_buffer_event_data(event);
1397         entry->ip = (unsigned long)kp->addr;
1398         store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1399
1400         if (!filter_current_check_discard(buffer, call, entry, event))
1401                 trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
1402 }
1403
1404 /* Kretprobe handler */
1405 static __kprobes void kretprobe_trace_func(struct kretprobe_instance *ri,
1406                                           struct pt_regs *regs)
1407 {
1408         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1409         struct kretprobe_trace_entry_head *entry;
1410         struct ring_buffer_event *event;
1411         struct ring_buffer *buffer;
1412         int size, pc, dsize;
1413         unsigned long irq_flags;
1414         struct ftrace_event_call *call = &tp->call;
1415
1416         local_save_flags(irq_flags);
1417         pc = preempt_count();
1418
1419         dsize = __get_data_size(tp, regs);
1420         size = sizeof(*entry) + tp->size + dsize;
1421
1422         event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
1423                                                   size, irq_flags, pc);
1424         if (!event)
1425                 return;
1426
1427         entry = ring_buffer_event_data(event);
1428         entry->func = (unsigned long)tp->rp.kp.addr;
1429         entry->ret_ip = (unsigned long)ri->ret_addr;
1430         store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1431
1432         if (!filter_current_check_discard(buffer, call, entry, event))
1433                 trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
1434 }
1435
1436 /* Event entry printers */
1437 enum print_line_t
1438 print_kprobe_event(struct trace_iterator *iter, int flags,
1439                    struct trace_event *event)
1440 {
1441         struct kprobe_trace_entry_head *field;
1442         struct trace_seq *s = &iter->seq;
1443         struct trace_probe *tp;
1444         u8 *data;
1445         int i;
1446
1447         field = (struct kprobe_trace_entry_head *)iter->ent;
1448         tp = container_of(event, struct trace_probe, call.event);
1449
1450         if (!trace_seq_printf(s, "%s: (", tp->call.name))
1451                 goto partial;
1452
1453         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1454                 goto partial;
1455
1456         if (!trace_seq_puts(s, ")"))
1457                 goto partial;
1458
1459         data = (u8 *)&field[1];
1460         for (i = 0; i < tp->nr_args; i++)
1461                 if (!tp->args[i].type->print(s, tp->args[i].name,
1462                                              data + tp->args[i].offset, field))
1463                         goto partial;
1464
1465         if (!trace_seq_puts(s, "\n"))
1466                 goto partial;
1467
1468         return TRACE_TYPE_HANDLED;
1469 partial:
1470         return TRACE_TYPE_PARTIAL_LINE;
1471 }
1472
1473 enum print_line_t
1474 print_kretprobe_event(struct trace_iterator *iter, int flags,
1475                       struct trace_event *event)
1476 {
1477         struct kretprobe_trace_entry_head *field;
1478         struct trace_seq *s = &iter->seq;
1479         struct trace_probe *tp;
1480         u8 *data;
1481         int i;
1482
1483         field = (struct kretprobe_trace_entry_head *)iter->ent;
1484         tp = container_of(event, struct trace_probe, call.event);
1485
1486         if (!trace_seq_printf(s, "%s: (", tp->call.name))
1487                 goto partial;
1488
1489         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1490                 goto partial;
1491
1492         if (!trace_seq_puts(s, " <- "))
1493                 goto partial;
1494
1495         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1496                 goto partial;
1497
1498         if (!trace_seq_puts(s, ")"))
1499                 goto partial;
1500
1501         data = (u8 *)&field[1];
1502         for (i = 0; i < tp->nr_args; i++)
1503                 if (!tp->args[i].type->print(s, tp->args[i].name,
1504                                              data + tp->args[i].offset, field))
1505                         goto partial;
1506
1507         if (!trace_seq_puts(s, "\n"))
1508                 goto partial;
1509
1510         return TRACE_TYPE_HANDLED;
1511 partial:
1512         return TRACE_TYPE_PARTIAL_LINE;
1513 }
1514
1515 static int probe_event_enable(struct ftrace_event_call *call)
1516 {
1517         struct trace_probe *tp = (struct trace_probe *)call->data;
1518
1519         tp->flags |= TP_FLAG_TRACE;
1520         if (probe_is_return(tp))
1521                 return enable_kretprobe(&tp->rp);
1522         else
1523                 return enable_kprobe(&tp->rp.kp);
1524 }
1525
1526 static void probe_event_disable(struct ftrace_event_call *call)
1527 {
1528         struct trace_probe *tp = (struct trace_probe *)call->data;
1529
1530         tp->flags &= ~TP_FLAG_TRACE;
1531         if (!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE))) {
1532                 if (probe_is_return(tp))
1533                         disable_kretprobe(&tp->rp);
1534                 else
1535                         disable_kprobe(&tp->rp.kp);
1536         }
1537 }
1538
1539 #undef DEFINE_FIELD
1540 #define DEFINE_FIELD(type, item, name, is_signed)                       \
1541         do {                                                            \
1542                 ret = trace_define_field(event_call, #type, name,       \
1543                                          offsetof(typeof(field), item), \
1544                                          sizeof(field.item), is_signed, \
1545                                          FILTER_OTHER);                 \
1546                 if (ret)                                                \
1547                         return ret;                                     \
1548         } while (0)
1549
1550 static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
1551 {
1552         int ret, i;
1553         struct kprobe_trace_entry_head field;
1554         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1555
1556         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1557         /* Set argument names as fields */
1558         for (i = 0; i < tp->nr_args; i++) {
1559                 ret = trace_define_field(event_call, tp->args[i].type->fmttype,
1560                                          tp->args[i].name,
1561                                          sizeof(field) + tp->args[i].offset,
1562                                          tp->args[i].type->size,
1563                                          tp->args[i].type->is_signed,
1564                                          FILTER_OTHER);
1565                 if (ret)
1566                         return ret;
1567         }
1568         return 0;
1569 }
1570
1571 static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
1572 {
1573         int ret, i;
1574         struct kretprobe_trace_entry_head field;
1575         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1576
1577         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1578         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1579         /* Set argument names as fields */
1580         for (i = 0; i < tp->nr_args; i++) {
1581                 ret = trace_define_field(event_call, tp->args[i].type->fmttype,
1582                                          tp->args[i].name,
1583                                          sizeof(field) + tp->args[i].offset,
1584                                          tp->args[i].type->size,
1585                                          tp->args[i].type->is_signed,
1586                                          FILTER_OTHER);
1587                 if (ret)
1588                         return ret;
1589         }
1590         return 0;
1591 }
1592
1593 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len)
1594 {
1595         int i;
1596         int pos = 0;
1597
1598         const char *fmt, *arg;
1599
1600         if (!probe_is_return(tp)) {
1601                 fmt = "(%lx)";
1602                 arg = "REC->" FIELD_STRING_IP;
1603         } else {
1604                 fmt = "(%lx <- %lx)";
1605                 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
1606         }
1607
1608         /* When len=0, we just calculate the needed length */
1609 #define LEN_OR_ZERO (len ? len - pos : 0)
1610
1611         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
1612
1613         for (i = 0; i < tp->nr_args; i++) {
1614                 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
1615                                 tp->args[i].name, tp->args[i].type->fmt);
1616         }
1617
1618         pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
1619
1620         for (i = 0; i < tp->nr_args; i++) {
1621                 if (strcmp(tp->args[i].type->name, "string") == 0)
1622                         pos += snprintf(buf + pos, LEN_OR_ZERO,
1623                                         ", __get_str(%s)",
1624                                         tp->args[i].name);
1625                 else
1626                         pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
1627                                         tp->args[i].name);
1628         }
1629
1630 #undef LEN_OR_ZERO
1631
1632         /* return the length of print_fmt */
1633         return pos;
1634 }
1635
1636 static int set_print_fmt(struct trace_probe *tp)
1637 {
1638         int len;
1639         char *print_fmt;
1640
1641         /* First: called with 0 length to calculate the needed length */
1642         len = __set_print_fmt(tp, NULL, 0);
1643         print_fmt = kmalloc(len + 1, GFP_KERNEL);
1644         if (!print_fmt)
1645                 return -ENOMEM;
1646
1647         /* Second: actually write the @print_fmt */
1648         __set_print_fmt(tp, print_fmt, len + 1);
1649         tp->call.print_fmt = print_fmt;
1650
1651         return 0;
1652 }
1653
1654 #ifdef CONFIG_PERF_EVENTS
1655
1656 /* Kprobe profile handler */
1657 static __kprobes void kprobe_perf_func(struct kprobe *kp,
1658                                          struct pt_regs *regs)
1659 {
1660         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1661         struct ftrace_event_call *call = &tp->call;
1662         struct kprobe_trace_entry_head *entry;
1663         struct hlist_head *head;
1664         int size, __size, dsize;
1665         int rctx;
1666
1667         dsize = __get_data_size(tp, regs);
1668         __size = sizeof(*entry) + tp->size + dsize;
1669         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1670         size -= sizeof(u32);
1671         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1672                      "profile buffer not large enough"))
1673                 return;
1674
1675         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1676         if (!entry)
1677                 return;
1678
1679         entry->ip = (unsigned long)kp->addr;
1680         memset(&entry[1], 0, dsize);
1681         store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1682
1683         head = this_cpu_ptr(call->perf_events);
1684         perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head);
1685 }
1686
1687 /* Kretprobe profile handler */
1688 static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri,
1689                                             struct pt_regs *regs)
1690 {
1691         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1692         struct ftrace_event_call *call = &tp->call;
1693         struct kretprobe_trace_entry_head *entry;
1694         struct hlist_head *head;
1695         int size, __size, dsize;
1696         int rctx;
1697
1698         dsize = __get_data_size(tp, regs);
1699         __size = sizeof(*entry) + tp->size + dsize;
1700         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1701         size -= sizeof(u32);
1702         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1703                      "profile buffer not large enough"))
1704                 return;
1705
1706         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1707         if (!entry)
1708                 return;
1709
1710         entry->func = (unsigned long)tp->rp.kp.addr;
1711         entry->ret_ip = (unsigned long)ri->ret_addr;
1712         store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1713
1714         head = this_cpu_ptr(call->perf_events);
1715         perf_trace_buf_submit(entry, size, rctx, entry->ret_ip, 1, regs, head);
1716 }
1717
1718 static int probe_perf_enable(struct ftrace_event_call *call)
1719 {
1720         struct trace_probe *tp = (struct trace_probe *)call->data;
1721
1722         tp->flags |= TP_FLAG_PROFILE;
1723
1724         if (probe_is_return(tp))
1725                 return enable_kretprobe(&tp->rp);
1726         else
1727                 return enable_kprobe(&tp->rp.kp);
1728 }
1729
1730 static void probe_perf_disable(struct ftrace_event_call *call)
1731 {
1732         struct trace_probe *tp = (struct trace_probe *)call->data;
1733
1734         tp->flags &= ~TP_FLAG_PROFILE;
1735
1736         if (!(tp->flags & TP_FLAG_TRACE)) {
1737                 if (probe_is_return(tp))
1738                         disable_kretprobe(&tp->rp);
1739                 else
1740                         disable_kprobe(&tp->rp.kp);
1741         }
1742 }
1743 #endif  /* CONFIG_PERF_EVENTS */
1744
1745 static __kprobes
1746 int kprobe_register(struct ftrace_event_call *event, enum trace_reg type)
1747 {
1748         switch (type) {
1749         case TRACE_REG_REGISTER:
1750                 return probe_event_enable(event);
1751         case TRACE_REG_UNREGISTER:
1752                 probe_event_disable(event);
1753                 return 0;
1754
1755 #ifdef CONFIG_PERF_EVENTS
1756         case TRACE_REG_PERF_REGISTER:
1757                 return probe_perf_enable(event);
1758         case TRACE_REG_PERF_UNREGISTER:
1759                 probe_perf_disable(event);
1760                 return 0;
1761 #endif
1762         }
1763         return 0;
1764 }
1765
1766 static __kprobes
1767 int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1768 {
1769         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1770
1771         if (tp->flags & TP_FLAG_TRACE)
1772                 kprobe_trace_func(kp, regs);
1773 #ifdef CONFIG_PERF_EVENTS
1774         if (tp->flags & TP_FLAG_PROFILE)
1775                 kprobe_perf_func(kp, regs);
1776 #endif
1777         return 0;       /* We don't tweek kernel, so just return 0 */
1778 }
1779
1780 static __kprobes
1781 int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1782 {
1783         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1784
1785         if (tp->flags & TP_FLAG_TRACE)
1786                 kretprobe_trace_func(ri, regs);
1787 #ifdef CONFIG_PERF_EVENTS
1788         if (tp->flags & TP_FLAG_PROFILE)
1789                 kretprobe_perf_func(ri, regs);
1790 #endif
1791         return 0;       /* We don't tweek kernel, so just return 0 */
1792 }
1793
1794 static struct trace_event_functions kretprobe_funcs = {
1795         .trace          = print_kretprobe_event
1796 };
1797
1798 static struct trace_event_functions kprobe_funcs = {
1799         .trace          = print_kprobe_event
1800 };
1801
1802 static int register_probe_event(struct trace_probe *tp)
1803 {
1804         struct ftrace_event_call *call = &tp->call;
1805         int ret;
1806
1807         /* Initialize ftrace_event_call */
1808         INIT_LIST_HEAD(&call->class->fields);
1809         if (probe_is_return(tp)) {
1810                 call->event.funcs = &kretprobe_funcs;
1811                 call->class->define_fields = kretprobe_event_define_fields;
1812         } else {
1813                 call->event.funcs = &kprobe_funcs;
1814                 call->class->define_fields = kprobe_event_define_fields;
1815         }
1816         if (set_print_fmt(tp) < 0)
1817                 return -ENOMEM;
1818         ret = register_ftrace_event(&call->event);
1819         if (!ret) {
1820                 kfree(call->print_fmt);
1821                 return -ENODEV;
1822         }
1823         call->flags = 0;
1824         call->class->reg = kprobe_register;
1825         call->data = tp;
1826         ret = trace_add_event_call(call);
1827         if (ret) {
1828                 pr_info("Failed to register kprobe event: %s\n", call->name);
1829                 kfree(call->print_fmt);
1830                 unregister_ftrace_event(&call->event);
1831         }
1832         return ret;
1833 }
1834
1835 static void unregister_probe_event(struct trace_probe *tp)
1836 {
1837         /* tp->event is unregistered in trace_remove_event_call() */
1838         trace_remove_event_call(&tp->call);
1839         kfree(tp->call.print_fmt);
1840 }
1841
1842 /* Make a debugfs interface for controlling probe points */
1843 static __init int init_kprobe_trace(void)
1844 {
1845         struct dentry *d_tracer;
1846         struct dentry *entry;
1847
1848         d_tracer = tracing_init_dentry();
1849         if (!d_tracer)
1850                 return 0;
1851
1852         entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
1853                                     NULL, &kprobe_events_ops);
1854
1855         /* Event list interface */
1856         if (!entry)
1857                 pr_warning("Could not create debugfs "
1858                            "'kprobe_events' entry\n");
1859
1860         /* Profile interface */
1861         entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
1862                                     NULL, &kprobe_profile_ops);
1863
1864         if (!entry)
1865                 pr_warning("Could not create debugfs "
1866                            "'kprobe_profile' entry\n");
1867         return 0;
1868 }
1869 fs_initcall(init_kprobe_trace);
1870
1871
1872 #ifdef CONFIG_FTRACE_STARTUP_TEST
1873
1874 static int kprobe_trace_selftest_target(int a1, int a2, int a3,
1875                                         int a4, int a5, int a6)
1876 {
1877         return a1 + a2 + a3 + a4 + a5 + a6;
1878 }
1879
1880 static __init int kprobe_trace_self_tests_init(void)
1881 {
1882         int ret, warn = 0;
1883         int (*target)(int, int, int, int, int, int);
1884         struct trace_probe *tp;
1885
1886         target = kprobe_trace_selftest_target;
1887
1888         pr_info("Testing kprobe tracing: ");
1889
1890         ret = command_trace_probe("p:testprobe kprobe_trace_selftest_target "
1891                                   "$stack $stack0 +0($stack)");
1892         if (WARN_ON_ONCE(ret)) {
1893                 pr_warning("error on probing function entry.\n");
1894                 warn++;
1895         } else {
1896                 /* Enable trace point */
1897                 tp = find_probe_event("testprobe", KPROBE_EVENT_SYSTEM);
1898                 if (WARN_ON_ONCE(tp == NULL)) {
1899                         pr_warning("error on getting new probe.\n");
1900                         warn++;
1901                 } else
1902                         probe_event_enable(&tp->call);
1903         }
1904
1905         ret = command_trace_probe("r:testprobe2 kprobe_trace_selftest_target "
1906                                   "$retval");
1907         if (WARN_ON_ONCE(ret)) {
1908                 pr_warning("error on probing function return.\n");
1909                 warn++;
1910         } else {
1911                 /* Enable trace point */
1912                 tp = find_probe_event("testprobe2", KPROBE_EVENT_SYSTEM);
1913                 if (WARN_ON_ONCE(tp == NULL)) {
1914                         pr_warning("error on getting new probe.\n");
1915                         warn++;
1916                 } else
1917                         probe_event_enable(&tp->call);
1918         }
1919
1920         if (warn)
1921                 goto end;
1922
1923         ret = target(1, 2, 3, 4, 5, 6);
1924
1925         ret = command_trace_probe("-:testprobe");
1926         if (WARN_ON_ONCE(ret)) {
1927                 pr_warning("error on deleting a probe.\n");
1928                 warn++;
1929         }
1930
1931         ret = command_trace_probe("-:testprobe2");
1932         if (WARN_ON_ONCE(ret)) {
1933                 pr_warning("error on deleting a probe.\n");
1934                 warn++;
1935         }
1936
1937 end:
1938         cleanup_all_probes();
1939         if (warn)
1940                 pr_cont("NG: Some tests are failed. Please check them.\n");
1941         else
1942                 pr_cont("OK\n");
1943         return 0;
1944 }
1945
1946 late_initcall(kprobe_trace_self_tests_init);
1947
1948 #endif