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 /* Default (unsigned long) fetch type */
 357 #define __DEFAULT_FETCH_TYPE(t) u##t
 358 #define _DEFAULT_FETCH_TYPE(t) __DEFAULT_FETCH_TYPE(t)
 359 #define DEFAULT_FETCH_TYPE _DEFAULT_FETCH_TYPE(BITS_PER_LONG)
 360 #define DEFAULT_FETCH_TYPE_STR __stringify(DEFAULT_FETCH_TYPE)
 361
 362 /* Fetch types */
 363 enum {
 364         FETCH_MTD_reg = 0,
 365         FETCH_MTD_stack,
 366         FETCH_MTD_retval,
 367         FETCH_MTD_memory,
 368         FETCH_MTD_symbol,
 369         FETCH_MTD_deref,
 370         FETCH_MTD_END,
 371 };
 372
 373 #define ASSIGN_FETCH_FUNC(method, type) \
 374         [FETCH_MTD_##method] = FETCH_FUNC_NAME(method, type)
 375
 376 #define __ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, _fmttype) \
 377         {.name = _name,                         \
 378          .size = _size,                                 \
 379          .is_signed = sign,                             \
 380          .print = PRINT_TYPE_FUNC_NAME(ptype),          \
 381          .fmt = PRINT_TYPE_FMT_NAME(ptype),             \
 382          .fmttype = _fmttype,                           \
 383          .fetch = {                                     \
 384 ASSIGN_FETCH_FUNC(reg, ftype),                          \
 385 ASSIGN_FETCH_FUNC(stack, ftype),                        \
 386 ASSIGN_FETCH_FUNC(retval, ftype),                       \
 387 ASSIGN_FETCH_FUNC(memory, ftype),                       \
 388 ASSIGN_FETCH_FUNC(symbol, ftype),                       \
 389 ASSIGN_FETCH_FUNC(deref, ftype),                        \
 390           }                                             \
 391         }
 392
 393 #define ASSIGN_FETCH_TYPE(ptype, ftype, sign)                   \
 394         __ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #ptype)
 395
 396 #define FETCH_TYPE_STRING 0
 397 #define FETCH_TYPE_STRSIZE 1
 398
 399 /* Fetch type information table */
 400 static const struct fetch_type {
 401         const char      *name;          /* Name of type */
 402         size_t          size;           /* Byte size of type */
 403         int             is_signed;      /* Signed flag */
 404         print_type_func_t       print;  /* Print functions */
 405         const char      *fmt;           /* Fromat string */
 406         const char      *fmttype;       /* Name in format file */
 407         /* Fetch functions */
 408         fetch_func_t    fetch[FETCH_MTD_END];
 409 } fetch_type_table[] = {
 410         /* Special types */
 411         [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
 412                                         sizeof(u32), 1, "__data_loc char[]"),
 413         [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
 414                                         string_size, sizeof(u32), 0, "u32"),
 415         /* Basic types */
 416         ASSIGN_FETCH_TYPE(u8,  u8,  0),
 417         ASSIGN_FETCH_TYPE(u16, u16, 0),
 418         ASSIGN_FETCH_TYPE(u32, u32, 0),
 419         ASSIGN_FETCH_TYPE(u64, u64, 0),
 420         ASSIGN_FETCH_TYPE(s8,  u8,  1),
 421         ASSIGN_FETCH_TYPE(s16, u16, 1),
 422         ASSIGN_FETCH_TYPE(s32, u32, 1),
 423         ASSIGN_FETCH_TYPE(s64, u64, 1),
 424 };
 425
 426 static const struct fetch_type *find_fetch_type(const char *type)
 427 {
 428         int i;
 429
 430         if (!type)
 431                 type = DEFAULT_FETCH_TYPE_STR;
 432
 433         for (i = 0; i < ARRAY_SIZE(fetch_type_table); i++)
 434                 if (strcmp(type, fetch_type_table[i].name) == 0)
 435                         return &fetch_type_table[i];
 436         return NULL;
 437 }
 438
 439 /* Special function : only accept unsigned long */
 440 static __kprobes void fetch_stack_address(struct pt_regs *regs,
 441                                           void *dummy, void *dest)
 442 {
 443         *(unsigned long *)dest = kernel_stack_pointer(regs);
 444 }
 445
 446 static fetch_func_t get_fetch_size_function(const struct fetch_type *type,
 447                                             fetch_func_t orig_fn)
 448 {
 449         int i;
 450
 451         if (type != &fetch_type_table[FETCH_TYPE_STRING])
 452                 return NULL;    /* Only string type needs size function */
 453         for (i = 0; i < FETCH_MTD_END; i++)
 454                 if (type->fetch[i] == orig_fn)
 455                         return fetch_type_table[FETCH_TYPE_STRSIZE].fetch[i];
 456
 457         WARN_ON(1);     /* This should not happen */
 458         return NULL;
 459 }
 460
 461 /**
 462  * Kprobe event core functions
 463  */
 464
 465 struct probe_arg {
 466         struct fetch_param      fetch;
 467         struct fetch_param      fetch_size;
 468         unsigned int            offset; /* Offset from argument entry */
 469         const char              *name;  /* Name of this argument */
 470         const char              *comm;  /* Command of this argument */
 471         const struct fetch_type *type;  /* Type of this argument */
 472 };
 473
 474 /* Flags for trace_probe */
 475 #define TP_FLAG_TRACE   1
 476 #define TP_FLAG_PROFILE 2
 477
 478 struct trace_probe {
 479         struct list_head        list;
 480         struct kretprobe        rp;     /* Use rp.kp for kprobe use */
 481         unsigned long           nhit;
 482         unsigned int            flags;  /* For TP_FLAG_* */
 483         const char              *symbol;        /* symbol name */
 484         struct ftrace_event_class       class;
 485         struct ftrace_event_call        call;
 486         ssize_t                 size;           /* trace entry size */
 487         unsigned int            nr_args;
 488         struct probe_arg        args[];
 489 };
 490
 491 #define SIZEOF_TRACE_PROBE(n)                   \
 492         (offsetof(struct trace_probe, args) +   \
 493         (sizeof(struct probe_arg) * (n)))
 494
 495
 496 static __kprobes int probe_is_return(struct trace_probe *tp)
 497 {
 498         return tp->rp.handler != NULL;
 499 }
 500
 501 static __kprobes const char *probe_symbol(struct trace_probe *tp)
 502 {
 503         return tp->symbol ? tp->symbol : "unknown";
 504 }
 505
 506 static int register_probe_event(struct trace_probe *tp);
 507 static void unregister_probe_event(struct trace_probe *tp);
 508
 509 static DEFINE_MUTEX(probe_lock);
 510 static LIST_HEAD(probe_list);
 511
 512 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
 513 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
 514                                 struct pt_regs *regs);
 515
 516 /* Check the name is good for event/group/fields */
 517 static int is_good_name(const char *name)
 518 {
 519         if (!isalpha(*name) && *name != '_')
 520                 return 0;
 521         while (*++name != '\0') {
 522                 if (!isalpha(*name) && !isdigit(*name) && *name != '_')
 523                         return 0;
 524         }
 525         return 1;
 526 }
 527
 528 /*
 529  * Allocate new trace_probe and initialize it (including kprobes).
 530  */
 531 static struct trace_probe *alloc_trace_probe(const char *group,
 532                                              const char *event,
 533                                              void *addr,
 534                                              const char *symbol,
 535                                              unsigned long offs,
 536                                              int nargs, int is_return)
 537 {
 538         struct trace_probe *tp;
 539         int ret = -ENOMEM;
 540
 541         tp = kzalloc(SIZEOF_TRACE_PROBE(nargs), GFP_KERNEL);
 542         if (!tp)
 543                 return ERR_PTR(ret);
 544
 545         if (symbol) {
 546                 tp->symbol = kstrdup(symbol, GFP_KERNEL);
 547                 if (!tp->symbol)
 548                         goto error;
 549                 tp->rp.kp.symbol_name = tp->symbol;
 550                 tp->rp.kp.offset = offs;
 551         } else
 552                 tp->rp.kp.addr = addr;
 553
 554         if (is_return)
 555                 tp->rp.handler = kretprobe_dispatcher;
 556         else
 557                 tp->rp.kp.pre_handler = kprobe_dispatcher;
 558
 559         if (!event || !is_good_name(event)) {
 560                 ret = -EINVAL;
 561                 goto error;
 562         }
 563
 564         tp->call.class = &tp->class;
 565         tp->call.name = kstrdup(event, GFP_KERNEL);
 566         if (!tp->call.name)
 567                 goto error;
 568
 569         if (!group || !is_good_name(group)) {
 570                 ret = -EINVAL;
 571                 goto error;
 572         }
 573
 574         tp->class.system = kstrdup(group, GFP_KERNEL);
 575         if (!tp->class.system)
 576                 goto error;
 577
 578         INIT_LIST_HEAD(&tp->list);
 579         return tp;
 580 error:
 581         kfree(tp->call.name);
 582         kfree(tp->symbol);
 583         kfree(tp);
 584         return ERR_PTR(ret);
 585 }
 586
 587 static void free_probe_arg(struct probe_arg *arg)
 588 {
 589         if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
 590                 free_deref_fetch_param(arg->fetch.data);
 591         else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
 592                 free_symbol_cache(arg->fetch.data);
 593         kfree(arg->name);
 594         kfree(arg->comm);
 595 }
 596
 597 static void free_trace_probe(struct trace_probe *tp)
 598 {
 599         int i;
 600
 601         for (i = 0; i < tp->nr_args; i++)
 602                 free_probe_arg(&tp->args[i]);
 603
 604         kfree(tp->call.class->system);
 605         kfree(tp->call.name);
 606         kfree(tp->symbol);
 607         kfree(tp);
 608 }
 609
 610 static struct trace_probe *find_probe_event(const char *event,
 611                                             const char *group)
 612 {
 613         struct trace_probe *tp;
 614
 615         list_for_each_entry(tp, &probe_list, list)
 616                 if (strcmp(tp->call.name, event) == 0 &&
 617                     strcmp(tp->call.class->system, group) == 0)
 618                         return tp;
 619         return NULL;
 620 }
 621
 622 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
 623 static void unregister_trace_probe(struct trace_probe *tp)
 624 {
 625         if (probe_is_return(tp))
 626                 unregister_kretprobe(&tp->rp);
 627         else
 628                 unregister_kprobe(&tp->rp.kp);
 629         list_del(&tp->list);
 630         unregister_probe_event(tp);
 631 }
 632
 633 /* Register a trace_probe and probe_event */
 634 static int register_trace_probe(struct trace_probe *tp)
 635 {
 636         struct trace_probe *old_tp;
 637         int ret;
 638
 639         mutex_lock(&probe_lock);
 640
 641         /* register as an event */
 642         old_tp = find_probe_event(tp->call.name, tp->call.class->system);
 643         if (old_tp) {
 644                 /* delete old event */
 645                 unregister_trace_probe(old_tp);
 646                 free_trace_probe(old_tp);
 647         }
 648         ret = register_probe_event(tp);
 649         if (ret) {
 650                 pr_warning("Failed to register probe event(%d)\n", ret);
 651                 goto end;
 652         }
 653
 654         tp->rp.kp.flags |= KPROBE_FLAG_DISABLED;
 655         if (probe_is_return(tp))
 656                 ret = register_kretprobe(&tp->rp);
 657         else
 658                 ret = register_kprobe(&tp->rp.kp);
 659
 660         if (ret) {
 661                 pr_warning("Could not insert probe(%d)\n", ret);
 662                 if (ret == -EILSEQ) {
 663                         pr_warning("Probing address(0x%p) is not an "
 664                                    "instruction boundary.\n",
 665                                    tp->rp.kp.addr);
 666                         ret = -EINVAL;
 667                 }
 668                 unregister_probe_event(tp);
 669         } else
 670                 list_add_tail(&tp->list, &probe_list);
 671 end:
 672         mutex_unlock(&probe_lock);
 673         return ret;
 674 }
 675
 676 /* Split symbol and offset. */
 677 static int split_symbol_offset(char *symbol, unsigned long *offset)
 678 {
 679         char *tmp;
 680         int ret;
 681
 682         if (!offset)
 683                 return -EINVAL;
 684
 685         tmp = strchr(symbol, '+');
 686         if (tmp) {
 687                 /* skip sign because strict_strtol doesn't accept '+' */
 688                 ret = strict_strtoul(tmp + 1, 0, offset);
 689                 if (ret)
 690                         return ret;
 691                 *tmp = '\0';
 692         } else
 693                 *offset = 0;
 694         return 0;
 695 }
 696
 697 #define PARAM_MAX_ARGS 16
 698 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
 699
 700 static int parse_probe_vars(char *arg, const struct fetch_type *t,
 701                             struct fetch_param *f, int is_return)
 702 {
 703         int ret = 0;
 704         unsigned long param;
 705
 706         if (strcmp(arg, "retval") == 0) {
 707                 if (is_return)
 708                         f->fn = t->fetch[FETCH_MTD_retval];
 709                 else
 710                         ret = -EINVAL;
 711         } else if (strncmp(arg, "stack", 5) == 0) {
 712                 if (arg[5] == '\0') {
 713                         if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR) == 0)
 714                                 f->fn = fetch_stack_address;
 715                         else
 716                                 ret = -EINVAL;
 717                 } else if (isdigit(arg[5])) {
 718                         ret = strict_strtoul(arg + 5, 10, &param);
 719                         if (ret || param > PARAM_MAX_STACK)
 720                                 ret = -EINVAL;
 721                         else {
 722                                 f->fn = t->fetch[FETCH_MTD_stack];
 723                                 f->data = (void *)param;
 724                         }
 725                 } else
 726                         ret = -EINVAL;
 727         } else
 728                 ret = -EINVAL;
 729         return ret;
 730 }
 731
 732 /* Recursive argument parser */
 733 static int __parse_probe_arg(char *arg, const struct fetch_type *t,
 734                              struct fetch_param *f, int is_return)
 735 {
 736         int ret = 0;
 737         unsigned long param;
 738         long offset;
 739         char *tmp;
 740
 741         switch (arg[0]) {
 742         case '$':
 743                 ret = parse_probe_vars(arg + 1, t, f, is_return);
 744                 break;
 745         case '%':       /* named register */
 746                 ret = regs_query_register_offset(arg + 1);
 747                 if (ret >= 0) {
 748                         f->fn = t->fetch[FETCH_MTD_reg];
 749                         f->data = (void *)(unsigned long)ret;
 750                         ret = 0;
 751                 }
 752                 break;
 753         case '@':       /* memory or symbol */
 754                 if (isdigit(arg[1])) {
 755                         ret = strict_strtoul(arg + 1, 0, &param);
 756                         if (ret)
 757                                 break;
 758                         f->fn = t->fetch[FETCH_MTD_memory];
 759                         f->data = (void *)param;
 760                 } else {
 761                         ret = split_symbol_offset(arg + 1, &offset);
 762                         if (ret)
 763                                 break;
 764                         f->data = alloc_symbol_cache(arg + 1, offset);
 765                         if (f->data)
 766                                 f->fn = t->fetch[FETCH_MTD_symbol];
 767                 }
 768                 break;
 769         case '+':       /* deref memory */
 770         case '-':
 771                 tmp = strchr(arg, '(');
 772                 if (!tmp)
 773                         break;
 774                 *tmp = '\0';
 775                 ret = strict_strtol(arg + 1, 0, &offset);
 776                 if (ret)
 777                         break;
 778                 if (arg[0] == '-')
 779                         offset = -offset;
 780                 arg = tmp + 1;
 781                 tmp = strrchr(arg, ')');
 782                 if (tmp) {
 783                         struct deref_fetch_param *dprm;
 784                         const struct fetch_type *t2 = find_fetch_type(NULL);
 785                         *tmp = '\0';
 786                         dprm = kzalloc(sizeof(struct deref_fetch_param),
 787                                        GFP_KERNEL);
 788                         if (!dprm)
 789                                 return -ENOMEM;
 790                         dprm->offset = offset;
 791                         ret = __parse_probe_arg(arg, t2, &dprm->orig,
 792                                                 is_return);
 793                         if (ret)
 794                                 kfree(dprm);
 795                         else {
 796                                 f->fn = t->fetch[FETCH_MTD_deref];
 797                                 f->data = (void *)dprm;
 798                         }
 799                 }
 800                 break;
 801         }
 802         if (!ret && !f->fn) {   /* Parsed, but do not find fetch method */
 803                 pr_info("%s type has no corresponding fetch method.\n",
 804                         t->name);
 805                 ret = -EINVAL;
 806         }
 807         return ret;
 808 }
 809
 810 /* String length checking wrapper */
 811 static int parse_probe_arg(char *arg, struct trace_probe *tp,
 812                            struct probe_arg *parg, int is_return)
 813 {
 814         const char *t;
 815         int ret;
 816
 817         if (strlen(arg) > MAX_ARGSTR_LEN) {
 818                 pr_info("Argument is too long.: %s\n",  arg);
 819                 return -ENOSPC;
 820         }
 821         parg->comm = kstrdup(arg, GFP_KERNEL);
 822         if (!parg->comm) {
 823                 pr_info("Failed to allocate memory for command '%s'.\n", arg);
 824                 return -ENOMEM;
 825         }
 826         t = strchr(parg->comm, ':');
 827         if (t) {
 828                 arg[t - parg->comm] = '\0';
 829                 t++;
 830         }
 831         parg->type = find_fetch_type(t);
 832         if (!parg->type) {
 833                 pr_info("Unsupported type: %s\n", t);
 834                 return -EINVAL;
 835         }
 836         parg->offset = tp->size;
 837         tp->size += parg->type->size;
 838         ret = __parse_probe_arg(arg, parg->type, &parg->fetch, is_return);
 839         if (ret >= 0) {
 840                 parg->fetch_size.fn = get_fetch_size_function(parg->type,
 841                                                               parg->fetch.fn);
 842                 parg->fetch_size.data = parg->fetch.data;
 843         }
 844         return ret;
 845 }
 846
 847 /* Return 1 if name is reserved or already used by another argument */
 848 static int conflict_field_name(const char *name,
 849                                struct probe_arg *args, int narg)
 850 {
 851         int i;
 852         for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
 853                 if (strcmp(reserved_field_names[i], name) == 0)
 854                         return 1;
 855         for (i = 0; i < narg; i++)
 856                 if (strcmp(args[i].name, name) == 0)
 857                         return 1;
 858         return 0;
 859 }
 860
 861 static int create_trace_probe(int argc, char **argv)
 862 {
 863         /*
 864          * Argument syntax:
 865          *  - Add kprobe: p[:[GRP/]EVENT] KSYM[+OFFS]|KADDR [FETCHARGS]
 866          *  - Add kretprobe: r[:[GRP/]EVENT] KSYM[+0] [FETCHARGS]
 867          * Fetch args:
 868          *  $retval     : fetch return value
 869          *  $stack      : fetch stack address
 870          *  $stackN     : fetch Nth of stack (N:0-)
 871          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 872          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 873          *  %REG        : fetch register REG
 874          * Dereferencing memory fetch:
 875          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 876          * Alias name of args:
 877          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 878          * Type of args:
 879          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 880          */
 881         struct trace_probe *tp;
 882         int i, ret = 0;
 883         int is_return = 0, is_delete = 0;
 884         char *symbol = NULL, *event = NULL, *group = NULL;
 885         char *arg;
 886         unsigned long offset = 0;
 887         void *addr = NULL;
 888         char buf[MAX_EVENT_NAME_LEN];
 889
 890         /* argc must be >= 1 */
 891         if (argv[0][0] == 'p')
 892                 is_return = 0;
 893         else if (argv[0][0] == 'r')
 894                 is_return = 1;
 895         else if (argv[0][0] == '-')
 896                 is_delete = 1;
 897         else {
 898                 pr_info("Probe definition must be started with 'p', 'r' or"
 899                         " '-'.\n");
 900                 return -EINVAL;
 901         }
 902
 903         if (argv[0][1] == ':') {
 904                 event = &argv[0][2];
 905                 if (strchr(event, '/')) {
 906                         group = event;
 907                         event = strchr(group, '/') + 1;
 908                         event[-1] = '\0';
 909                         if (strlen(group) == 0) {
 910                                 pr_info("Group name is not specified\n");
 911                                 return -EINVAL;
 912                         }
 913                 }
 914                 if (strlen(event) == 0) {
 915                         pr_info("Event name is not specified\n");
 916                         return -EINVAL;
 917                 }
 918         }
 919         if (!group)
 920                 group = KPROBE_EVENT_SYSTEM;
 921
 922         if (is_delete) {
 923                 if (!event) {
 924                         pr_info("Delete command needs an event name.\n");
 925                         return -EINVAL;
 926                 }
 927                 mutex_lock(&probe_lock);
 928                 tp = find_probe_event(event, group);
 929                 if (!tp) {
 930                         mutex_unlock(&probe_lock);
 931                         pr_info("Event %s/%s doesn't exist.\n", group, event);
 932                         return -ENOENT;
 933                 }
 934                 /* delete an event */
 935                 unregister_trace_probe(tp);
 936                 free_trace_probe(tp);
 937                 mutex_unlock(&probe_lock);
 938                 return 0;
 939         }
 940
 941         if (argc < 2) {
 942                 pr_info("Probe point is not specified.\n");
 943                 return -EINVAL;
 944         }
 945         if (isdigit(argv[1][0])) {
 946                 if (is_return) {
 947                         pr_info("Return probe point must be a symbol.\n");
 948                         return -EINVAL;
 949                 }
 950                 /* an address specified */
 951                 ret = strict_strtoul(&argv[1][0], 0, (unsigned long *)&addr);
 952                 if (ret) {
 953                         pr_info("Failed to parse address.\n");
 954                         return ret;
 955                 }
 956         } else {
 957                 /* a symbol specified */
 958                 symbol = argv[1];
 959                 /* TODO: support .init module functions */
 960                 ret = split_symbol_offset(symbol, &offset);
 961                 if (ret) {
 962                         pr_info("Failed to parse symbol.\n");
 963                         return ret;
 964                 }
 965                 if (offset && is_return) {
 966                         pr_info("Return probe must be used without offset.\n");
 967                         return -EINVAL;
 968                 }
 969         }
 970         argc -= 2; argv += 2;
 971
 972         /* setup a probe */
 973         if (!event) {
 974                 /* Make a new event name */
 975                 if (symbol)
 976                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
 977                                  is_return ? 'r' : 'p', symbol, offset);
 978                 else
 979                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
 980                                  is_return ? 'r' : 'p', addr);
 981                 event = buf;
 982         }
 983         tp = alloc_trace_probe(group, event, addr, symbol, offset, argc,
 984                                is_return);
 985         if (IS_ERR(tp)) {
 986                 pr_info("Failed to allocate trace_probe.(%d)\n",
 987                         (int)PTR_ERR(tp));
 988                 return PTR_ERR(tp);
 989         }
 990
 991         /* parse arguments */
 992         ret = 0;
 993         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 994                 /* Increment count for freeing args in error case */
 995                 tp->nr_args++;
 996
 997                 /* Parse argument name */
 998                 arg = strchr(argv[i], '=');
 999                 if (arg) {
1000                         *arg++ = '\0';
1001                         tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
1002                 } else {
1003                         arg = argv[i];
1004                         /* If argument name is omitted, set "argN" */
1005                         snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
1006                         tp->args[i].name = kstrdup(buf, GFP_KERNEL);
1007                 }
1008
1009                 if (!tp->args[i].name) {
1010                         pr_info("Failed to allocate argument[%d] name.\n", i);
1011                         ret = -ENOMEM;
1012                         goto error;
1013                 }
1014
1015                 if (!is_good_name(tp->args[i].name)) {
1016                         pr_info("Invalid argument[%d] name: %s\n",
1017                                 i, tp->args[i].name);
1018                         ret = -EINVAL;
1019                         goto error;
1020                 }
1021
1022                 if (conflict_field_name(tp->args[i].name, tp->args, i)) {
1023                         pr_info("Argument[%d] name '%s' conflicts with "
1024                                 "another field.\n", i, argv[i]);
1025                         ret = -EINVAL;
1026                         goto error;
1027                 }
1028
1029                 /* Parse fetch argument */
1030                 ret = parse_probe_arg(arg, tp, &tp->args[i], is_return);
1031                 if (ret) {
1032                         pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
1033                         goto error;
1034                 }
1035         }
1036
1037         ret = register_trace_probe(tp);
1038         if (ret)
1039                 goto error;
1040         return 0;
1041
1042 error:
1043         free_trace_probe(tp);
1044         return ret;
1045 }
1046
1047 static void cleanup_all_probes(void)
1048 {
1049         struct trace_probe *tp;
1050
1051         mutex_lock(&probe_lock);
1052         /* TODO: Use batch unregistration */
1053         while (!list_empty(&probe_list)) {
1054                 tp = list_entry(probe_list.next, struct trace_probe, list);
1055                 unregister_trace_probe(tp);
1056                 free_trace_probe(tp);
1057         }
1058         mutex_unlock(&probe_lock);
1059 }
1060
1061
1062 /* Probes listing interfaces */
1063 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
1064 {
1065         mutex_lock(&probe_lock);
1066         return seq_list_start(&probe_list, *pos);
1067 }
1068
1069 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
1070 {
1071         return seq_list_next(v, &probe_list, pos);
1072 }
1073
1074 static void probes_seq_stop(struct seq_file *m, void *v)
1075 {
1076         mutex_unlock(&probe_lock);
1077 }
1078
1079 static int probes_seq_show(struct seq_file *m, void *v)
1080 {
1081         struct trace_probe *tp = v;
1082         int i;
1083
1084         seq_printf(m, "%c", probe_is_return(tp) ? 'r' : 'p');
1085         seq_printf(m, ":%s/%s", tp->call.class->system, tp->call.name);
1086
1087         if (!tp->symbol)
1088                 seq_printf(m, " 0x%p", tp->rp.kp.addr);
1089         else if (tp->rp.kp.offset)
1090                 seq_printf(m, " %s+%u", probe_symbol(tp), tp->rp.kp.offset);
1091         else
1092                 seq_printf(m, " %s", probe_symbol(tp));
1093
1094         for (i = 0; i < tp->nr_args; i++)
1095                 seq_printf(m, " %s=%s", tp->args[i].name, tp->args[i].comm);
1096         seq_printf(m, "\n");
1097
1098         return 0;
1099 }
1100
1101 static const struct seq_operations probes_seq_op = {
1102         .start  = probes_seq_start,
1103         .next   = probes_seq_next,
1104         .stop   = probes_seq_stop,
1105         .show   = probes_seq_show
1106 };
1107
1108 static int probes_open(struct inode *inode, struct file *file)
1109 {
1110         if ((file->f_mode & FMODE_WRITE) &&
1111             (file->f_flags & O_TRUNC))
1112                 cleanup_all_probes();
1113
1114         return seq_open(file, &probes_seq_op);
1115 }
1116
1117 static int command_trace_probe(const char *buf)
1118 {
1119         char **argv;
1120         int argc = 0, ret = 0;
1121
1122         argv = argv_split(GFP_KERNEL, buf, &argc);
1123         if (!argv)
1124                 return -ENOMEM;
1125
1126         if (argc)
1127                 ret = create_trace_probe(argc, argv);
1128
1129         argv_free(argv);
1130         return ret;
1131 }
1132
1133 #define WRITE_BUFSIZE 128
1134
1135 static ssize_t probes_write(struct file *file, const char __user *buffer,
1136                             size_t count, loff_t *ppos)
1137 {
1138         char *kbuf, *tmp;
1139         int ret;
1140         size_t done;
1141         size_t size;
1142
1143         kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
1144         if (!kbuf)
1145                 return -ENOMEM;
1146
1147         ret = done = 0;
1148         while (done < count) {
1149                 size = count - done;
1150                 if (size >= WRITE_BUFSIZE)
1151                         size = WRITE_BUFSIZE - 1;
1152                 if (copy_from_user(kbuf, buffer + done, size)) {
1153                         ret = -EFAULT;
1154                         goto out;
1155                 }
1156                 kbuf[size] = '\0';
1157                 tmp = strchr(kbuf, '\n');
1158                 if (tmp) {
1159                         *tmp = '\0';
1160                         size = tmp - kbuf + 1;
1161                 } else if (done + size < count) {
1162                         pr_warning("Line length is too long: "
1163                                    "Should be less than %d.", WRITE_BUFSIZE);
1164                         ret = -EINVAL;
1165                         goto out;
1166                 }
1167                 done += size;
1168                 /* Remove comments */
1169                 tmp = strchr(kbuf, '#');
1170                 if (tmp)
1171                         *tmp = '\0';
1172
1173                 ret = command_trace_probe(kbuf);
1174                 if (ret)
1175                         goto out;
1176         }
1177         ret = done;
1178 out:
1179         kfree(kbuf);
1180         return ret;
1181 }
1182
1183 static const struct file_operations kprobe_events_ops = {
1184         .owner          = THIS_MODULE,
1185         .open           = probes_open,
1186         .read           = seq_read,
1187         .llseek         = seq_lseek,
1188         .release        = seq_release,
1189         .write          = probes_write,
1190 };
1191
1192 /* Probes profiling interfaces */
1193 static int probes_profile_seq_show(struct seq_file *m, void *v)
1194 {
1195         struct trace_probe *tp = v;
1196
1197         seq_printf(m, "  %-44s %15lu %15lu\n", tp->call.name, tp->nhit,
1198                    tp->rp.kp.nmissed);
1199
1200         return 0;
1201 }
1202
1203 static const struct seq_operations profile_seq_op = {
1204         .start  = probes_seq_start,
1205         .next   = probes_seq_next,
1206         .stop   = probes_seq_stop,
1207         .show   = probes_profile_seq_show
1208 };
1209
1210 static int profile_open(struct inode *inode, struct file *file)
1211 {
1212         return seq_open(file, &profile_seq_op);
1213 }
1214
1215 static const struct file_operations kprobe_profile_ops = {
1216         .owner          = THIS_MODULE,
1217         .open           = profile_open,
1218         .read           = seq_read,
1219         .llseek         = seq_lseek,
1220         .release        = seq_release,
1221 };
1222
1223 /* Sum up total data length for dynamic arraies (strings) */
1224 static __kprobes int __get_data_size(struct trace_probe *tp,
1225                                      struct pt_regs *regs)
1226 {
1227         int i, ret = 0;
1228         u32 len;
1229
1230         for (i = 0; i < tp->nr_args; i++)
1231                 if (unlikely(tp->args[i].fetch_size.fn)) {
1232                         call_fetch(&tp->args[i].fetch_size, regs, &len);
1233                         ret += len;
1234                 }
1235
1236         return ret;
1237 }
1238
1239 /* Store the value of each argument */
1240 static __kprobes void store_trace_args(int ent_size, struct trace_probe *tp,
1241                                        struct pt_regs *regs,
1242                                        u8 *data, int maxlen)
1243 {
1244         int i;
1245         u32 end = tp->size;
1246         u32 *dl;        /* Data (relative) location */
1247
1248         for (i = 0; i < tp->nr_args; i++) {
1249                 if (unlikely(tp->args[i].fetch_size.fn)) {
1250                         /*
1251                          * First, we set the relative location and
1252                          * maximum data length to *dl
1253                          */
1254                         dl = (u32 *)(data + tp->args[i].offset);
1255                         *dl = make_data_rloc(maxlen, end - tp->args[i].offset);
1256                         /* Then try to fetch string or dynamic array data */
1257                         call_fetch(&tp->args[i].fetch, regs, dl);
1258                         /* Reduce maximum length */
1259                         end += get_rloc_len(*dl);
1260                         maxlen -= get_rloc_len(*dl);
1261                         /* Trick here, convert data_rloc to data_loc */
1262                         *dl = convert_rloc_to_loc(*dl,
1263                                  ent_size + tp->args[i].offset);
1264                 } else
1265                         /* Just fetching data normally */
1266                         call_fetch(&tp->args[i].fetch, regs,
1267                                    data + tp->args[i].offset);
1268         }
1269 }
1270
1271 /* Kprobe handler */
1272 static __kprobes void kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
1273 {
1274         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1275         struct kprobe_trace_entry_head *entry;
1276         struct ring_buffer_event *event;
1277         struct ring_buffer *buffer;
1278         int size, dsize, pc;
1279         unsigned long irq_flags;
1280         struct ftrace_event_call *call = &tp->call;
1281
1282         tp->nhit++;
1283
1284         local_save_flags(irq_flags);
1285         pc = preempt_count();
1286
1287         dsize = __get_data_size(tp, regs);
1288         size = sizeof(*entry) + tp->size + dsize;
1289
1290         event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
1291                                                   size, irq_flags, pc);
1292         if (!event)
1293                 return;
1294
1295         entry = ring_buffer_event_data(event);
1296         entry->ip = (unsigned long)kp->addr;
1297         store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1298
1299         if (!filter_current_check_discard(buffer, call, entry, event))
1300                 trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
1301 }
1302
1303 /* Kretprobe handler */
1304 static __kprobes void kretprobe_trace_func(struct kretprobe_instance *ri,
1305                                           struct pt_regs *regs)
1306 {
1307         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1308         struct kretprobe_trace_entry_head *entry;
1309         struct ring_buffer_event *event;
1310         struct ring_buffer *buffer;
1311         int size, pc, dsize;
1312         unsigned long irq_flags;
1313         struct ftrace_event_call *call = &tp->call;
1314
1315         local_save_flags(irq_flags);
1316         pc = preempt_count();
1317
1318         dsize = __get_data_size(tp, regs);
1319         size = sizeof(*entry) + tp->size + dsize;
1320
1321         event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
1322                                                   size, irq_flags, pc);
1323         if (!event)
1324                 return;
1325
1326         entry = ring_buffer_event_data(event);
1327         entry->func = (unsigned long)tp->rp.kp.addr;
1328         entry->ret_ip = (unsigned long)ri->ret_addr;
1329         store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1330
1331         if (!filter_current_check_discard(buffer, call, entry, event))
1332                 trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
1333 }
1334
1335 /* Event entry printers */
1336 enum print_line_t
1337 print_kprobe_event(struct trace_iterator *iter, int flags,
1338                    struct trace_event *event)
1339 {
1340         struct kprobe_trace_entry_head *field;
1341         struct trace_seq *s = &iter->seq;
1342         struct trace_probe *tp;
1343         u8 *data;
1344         int i;
1345
1346         field = (struct kprobe_trace_entry_head *)iter->ent;
1347         tp = container_of(event, struct trace_probe, call.event);
1348
1349         if (!trace_seq_printf(s, "%s: (", tp->call.name))
1350                 goto partial;
1351
1352         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1353                 goto partial;
1354
1355         if (!trace_seq_puts(s, ")"))
1356                 goto partial;
1357
1358         data = (u8 *)&field[1];
1359         for (i = 0; i < tp->nr_args; i++)
1360                 if (!tp->args[i].type->print(s, tp->args[i].name,
1361                                              data + tp->args[i].offset, field))
1362                         goto partial;
1363
1364         if (!trace_seq_puts(s, "\n"))
1365                 goto partial;
1366
1367         return TRACE_TYPE_HANDLED;
1368 partial:
1369         return TRACE_TYPE_PARTIAL_LINE;
1370 }
1371
1372 enum print_line_t
1373 print_kretprobe_event(struct trace_iterator *iter, int flags,
1374                       struct trace_event *event)
1375 {
1376         struct kretprobe_trace_entry_head *field;
1377         struct trace_seq *s = &iter->seq;
1378         struct trace_probe *tp;
1379         u8 *data;
1380         int i;
1381
1382         field = (struct kretprobe_trace_entry_head *)iter->ent;
1383         tp = container_of(event, struct trace_probe, call.event);
1384
1385         if (!trace_seq_printf(s, "%s: (", tp->call.name))
1386                 goto partial;
1387
1388         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1389                 goto partial;
1390
1391         if (!trace_seq_puts(s, " <- "))
1392                 goto partial;
1393
1394         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1395                 goto partial;
1396
1397         if (!trace_seq_puts(s, ")"))
1398                 goto partial;
1399
1400         data = (u8 *)&field[1];
1401         for (i = 0; i < tp->nr_args; i++)
1402                 if (!tp->args[i].type->print(s, tp->args[i].name,
1403                                              data + tp->args[i].offset, field))
1404                         goto partial;
1405
1406         if (!trace_seq_puts(s, "\n"))
1407                 goto partial;
1408
1409         return TRACE_TYPE_HANDLED;
1410 partial:
1411         return TRACE_TYPE_PARTIAL_LINE;
1412 }
1413
1414 static int probe_event_enable(struct ftrace_event_call *call)
1415 {
1416         struct trace_probe *tp = (struct trace_probe *)call->data;
1417
1418         tp->flags |= TP_FLAG_TRACE;
1419         if (probe_is_return(tp))
1420                 return enable_kretprobe(&tp->rp);
1421         else
1422                 return enable_kprobe(&tp->rp.kp);
1423 }
1424
1425 static void probe_event_disable(struct ftrace_event_call *call)
1426 {
1427         struct trace_probe *tp = (struct trace_probe *)call->data;
1428
1429         tp->flags &= ~TP_FLAG_TRACE;
1430         if (!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE))) {
1431                 if (probe_is_return(tp))
1432                         disable_kretprobe(&tp->rp);
1433                 else
1434                         disable_kprobe(&tp->rp.kp);
1435         }
1436 }
1437
1438 #undef DEFINE_FIELD
1439 #define DEFINE_FIELD(type, item, name, is_signed)                       \
1440         do {                                                            \
1441                 ret = trace_define_field(event_call, #type, name,       \
1442                                          offsetof(typeof(field), item), \
1443                                          sizeof(field.item), is_signed, \
1444                                          FILTER_OTHER);                 \
1445                 if (ret)                                                \
1446                         return ret;                                     \
1447         } while (0)
1448
1449 static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
1450 {
1451         int ret, i;
1452         struct kprobe_trace_entry_head field;
1453         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1454
1455         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1456         /* Set argument names as fields */
1457         for (i = 0; i < tp->nr_args; i++) {
1458                 ret = trace_define_field(event_call, tp->args[i].type->fmttype,
1459                                          tp->args[i].name,
1460                                          sizeof(field) + tp->args[i].offset,
1461                                          tp->args[i].type->size,
1462                                          tp->args[i].type->is_signed,
1463                                          FILTER_OTHER);
1464                 if (ret)
1465                         return ret;
1466         }
1467         return 0;
1468 }
1469
1470 static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
1471 {
1472         int ret, i;
1473         struct kretprobe_trace_entry_head field;
1474         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1475
1476         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1477         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1478         /* Set argument names as fields */
1479         for (i = 0; i < tp->nr_args; i++) {
1480                 ret = trace_define_field(event_call, tp->args[i].type->fmttype,
1481                                          tp->args[i].name,
1482                                          sizeof(field) + tp->args[i].offset,
1483                                          tp->args[i].type->size,
1484                                          tp->args[i].type->is_signed,
1485                                          FILTER_OTHER);
1486                 if (ret)
1487                         return ret;
1488         }
1489         return 0;
1490 }
1491
1492 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len)
1493 {
1494         int i;
1495         int pos = 0;
1496
1497         const char *fmt, *arg;
1498
1499         if (!probe_is_return(tp)) {
1500                 fmt = "(%lx)";
1501                 arg = "REC->" FIELD_STRING_IP;
1502         } else {
1503                 fmt = "(%lx <- %lx)";
1504                 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
1505         }
1506
1507         /* When len=0, we just calculate the needed length */
1508 #define LEN_OR_ZERO (len ? len - pos : 0)
1509
1510         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
1511
1512         for (i = 0; i < tp->nr_args; i++) {
1513                 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
1514                                 tp->args[i].name, tp->args[i].type->fmt);
1515         }
1516
1517         pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
1518
1519         for (i = 0; i < tp->nr_args; i++) {
1520                 if (strcmp(tp->args[i].type->name, "string") == 0)
1521                         pos += snprintf(buf + pos, LEN_OR_ZERO,
1522                                         ", __get_str(%s)",
1523                                         tp->args[i].name);
1524                 else
1525                         pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
1526                                         tp->args[i].name);
1527         }
1528
1529 #undef LEN_OR_ZERO
1530
1531         /* return the length of print_fmt */
1532         return pos;
1533 }
1534
1535 static int set_print_fmt(struct trace_probe *tp)
1536 {
1537         int len;
1538         char *print_fmt;
1539
1540         /* First: called with 0 length to calculate the needed length */
1541         len = __set_print_fmt(tp, NULL, 0);
1542         print_fmt = kmalloc(len + 1, GFP_KERNEL);
1543         if (!print_fmt)
1544                 return -ENOMEM;
1545
1546         /* Second: actually write the @print_fmt */
1547         __set_print_fmt(tp, print_fmt, len + 1);
1548         tp->call.print_fmt = print_fmt;
1549
1550         return 0;
1551 }
1552
1553 #ifdef CONFIG_PERF_EVENTS
1554
1555 /* Kprobe profile handler */
1556 static __kprobes void kprobe_perf_func(struct kprobe *kp,
1557                                          struct pt_regs *regs)
1558 {
1559         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1560         struct ftrace_event_call *call = &tp->call;
1561         struct kprobe_trace_entry_head *entry;
1562         struct hlist_head *head;
1563         int size, __size, dsize;
1564         int rctx;
1565
1566         dsize = __get_data_size(tp, regs);
1567         __size = sizeof(*entry) + tp->size + dsize;
1568         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1569         size -= sizeof(u32);
1570         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1571                      "profile buffer not large enough"))
1572                 return;
1573
1574         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1575         if (!entry)
1576                 return;
1577
1578         entry->ip = (unsigned long)kp->addr;
1579         memset(&entry[1], 0, dsize);
1580         store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1581
1582         head = this_cpu_ptr(call->perf_events);
1583         perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head);
1584 }
1585
1586 /* Kretprobe profile handler */
1587 static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri,
1588                                             struct pt_regs *regs)
1589 {
1590         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1591         struct ftrace_event_call *call = &tp->call;
1592         struct kretprobe_trace_entry_head *entry;
1593         struct hlist_head *head;
1594         int size, __size, dsize;
1595         int rctx;
1596
1597         dsize = __get_data_size(tp, regs);
1598         __size = sizeof(*entry) + tp->size + dsize;
1599         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1600         size -= sizeof(u32);
1601         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1602                      "profile buffer not large enough"))
1603                 return;
1604
1605         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1606         if (!entry)
1607                 return;
1608
1609         entry->func = (unsigned long)tp->rp.kp.addr;
1610         entry->ret_ip = (unsigned long)ri->ret_addr;
1611         store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1612
1613         head = this_cpu_ptr(call->perf_events);
1614         perf_trace_buf_submit(entry, size, rctx, entry->ret_ip, 1, regs, head);
1615 }
1616
1617 static int probe_perf_enable(struct ftrace_event_call *call)
1618 {
1619         struct trace_probe *tp = (struct trace_probe *)call->data;
1620
1621         tp->flags |= TP_FLAG_PROFILE;
1622
1623         if (probe_is_return(tp))
1624                 return enable_kretprobe(&tp->rp);
1625         else
1626                 return enable_kprobe(&tp->rp.kp);
1627 }
1628
1629 static void probe_perf_disable(struct ftrace_event_call *call)
1630 {
1631         struct trace_probe *tp = (struct trace_probe *)call->data;
1632
1633         tp->flags &= ~TP_FLAG_PROFILE;
1634
1635         if (!(tp->flags & TP_FLAG_TRACE)) {
1636                 if (probe_is_return(tp))
1637                         disable_kretprobe(&tp->rp);
1638                 else
1639                         disable_kprobe(&tp->rp.kp);
1640         }
1641 }
1642 #endif  /* CONFIG_PERF_EVENTS */
1643
1644 static __kprobes
1645 int kprobe_register(struct ftrace_event_call *event, enum trace_reg type)
1646 {
1647         switch (type) {
1648         case TRACE_REG_REGISTER:
1649                 return probe_event_enable(event);
1650         case TRACE_REG_UNREGISTER:
1651                 probe_event_disable(event);
1652                 return 0;
1653
1654 #ifdef CONFIG_PERF_EVENTS
1655         case TRACE_REG_PERF_REGISTER:
1656                 return probe_perf_enable(event);
1657         case TRACE_REG_PERF_UNREGISTER:
1658                 probe_perf_disable(event);
1659                 return 0;
1660 #endif
1661         }
1662         return 0;
1663 }
1664
1665 static __kprobes
1666 int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1667 {
1668         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1669
1670         if (tp->flags & TP_FLAG_TRACE)
1671                 kprobe_trace_func(kp, regs);
1672 #ifdef CONFIG_PERF_EVENTS
1673         if (tp->flags & TP_FLAG_PROFILE)
1674                 kprobe_perf_func(kp, regs);
1675 #endif
1676         return 0;       /* We don't tweek kernel, so just return 0 */
1677 }
1678
1679 static __kprobes
1680 int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1681 {
1682         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1683
1684         if (tp->flags & TP_FLAG_TRACE)
1685                 kretprobe_trace_func(ri, regs);
1686 #ifdef CONFIG_PERF_EVENTS
1687         if (tp->flags & TP_FLAG_PROFILE)
1688                 kretprobe_perf_func(ri, regs);
1689 #endif
1690         return 0;       /* We don't tweek kernel, so just return 0 */
1691 }
1692
1693 static struct trace_event_functions kretprobe_funcs = {
1694         .trace          = print_kretprobe_event
1695 };
1696
1697 static struct trace_event_functions kprobe_funcs = {
1698         .trace          = print_kprobe_event
1699 };
1700
1701 static int register_probe_event(struct trace_probe *tp)
1702 {
1703         struct ftrace_event_call *call = &tp->call;
1704         int ret;
1705
1706         /* Initialize ftrace_event_call */
1707         INIT_LIST_HEAD(&call->class->fields);
1708         if (probe_is_return(tp)) {
1709                 call->event.funcs = &kretprobe_funcs;
1710                 call->class->define_fields = kretprobe_event_define_fields;
1711         } else {
1712                 call->event.funcs = &kprobe_funcs;
1713                 call->class->define_fields = kprobe_event_define_fields;
1714         }
1715         if (set_print_fmt(tp) < 0)
1716                 return -ENOMEM;
1717         ret = register_ftrace_event(&call->event);
1718         if (!ret) {
1719                 kfree(call->print_fmt);
1720                 return -ENODEV;
1721         }
1722         call->flags = 0;
1723         call->class->reg = kprobe_register;
1724         call->data = tp;
1725         ret = trace_add_event_call(call);
1726         if (ret) {
1727                 pr_info("Failed to register kprobe event: %s\n", call->name);
1728                 kfree(call->print_fmt);
1729                 unregister_ftrace_event(&call->event);
1730         }
1731         return ret;
1732 }
1733
1734 static void unregister_probe_event(struct trace_probe *tp)
1735 {
1736         /* tp->event is unregistered in trace_remove_event_call() */
1737         trace_remove_event_call(&tp->call);
1738         kfree(tp->call.print_fmt);
1739 }
1740
1741 /* Make a debugfs interface for controling probe points */
1742 static __init int init_kprobe_trace(void)
1743 {
1744         struct dentry *d_tracer;
1745         struct dentry *entry;
1746
1747         d_tracer = tracing_init_dentry();
1748         if (!d_tracer)
1749                 return 0;
1750
1751         entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
1752                                     NULL, &kprobe_events_ops);
1753
1754         /* Event list interface */
1755         if (!entry)
1756                 pr_warning("Could not create debugfs "
1757                            "'kprobe_events' entry\n");
1758
1759         /* Profile interface */
1760         entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
1761                                     NULL, &kprobe_profile_ops);
1762
1763         if (!entry)
1764                 pr_warning("Could not create debugfs "
1765                            "'kprobe_profile' entry\n");
1766         return 0;
1767 }
1768 fs_initcall(init_kprobe_trace);
1769
1770
1771 #ifdef CONFIG_FTRACE_STARTUP_TEST
1772
1773 static int kprobe_trace_selftest_target(int a1, int a2, int a3,
1774                                         int a4, int a5, int a6)
1775 {
1776         return a1 + a2 + a3 + a4 + a5 + a6;
1777 }
1778
1779 static __init int kprobe_trace_self_tests_init(void)
1780 {
1781         int ret, warn = 0;
1782         int (*target)(int, int, int, int, int, int);
1783         struct trace_probe *tp;
1784
1785         target = kprobe_trace_selftest_target;
1786
1787         pr_info("Testing kprobe tracing: ");
1788
1789         ret = command_trace_probe("p:testprobe kprobe_trace_selftest_target "
1790                                   "$stack $stack0 +0($stack)");
1791         if (WARN_ON_ONCE(ret)) {
1792                 pr_warning("error on probing function entry.\n");
1793                 warn++;
1794         } else {
1795                 /* Enable trace point */
1796                 tp = find_probe_event("testprobe", KPROBE_EVENT_SYSTEM);
1797                 if (WARN_ON_ONCE(tp == NULL)) {
1798                         pr_warning("error on getting new probe.\n");
1799                         warn++;
1800                 } else
1801                         probe_event_enable(&tp->call);
1802         }
1803
1804         ret = command_trace_probe("r:testprobe2 kprobe_trace_selftest_target "
1805                                   "$retval");
1806         if (WARN_ON_ONCE(ret)) {
1807                 pr_warning("error on probing function return.\n");
1808                 warn++;
1809         } else {
1810                 /* Enable trace point */
1811                 tp = find_probe_event("testprobe2", KPROBE_EVENT_SYSTEM);
1812                 if (WARN_ON_ONCE(tp == NULL)) {
1813                         pr_warning("error on getting new probe.\n");
1814                         warn++;
1815                 } else
1816                         probe_event_enable(&tp->call);
1817         }
1818
1819         if (warn)
1820                 goto end;
1821
1822         ret = target(1, 2, 3, 4, 5, 6);
1823
1824         ret = command_trace_probe("-:testprobe");
1825         if (WARN_ON_ONCE(ret)) {
1826                 pr_warning("error on deleting a probe.\n");
1827                 warn++;
1828         }
1829
1830         ret = command_trace_probe("-:testprobe2");
1831         if (WARN_ON_ONCE(ret)) {
1832                 pr_warning("error on deleting a probe.\n");
1833                 warn++;
1834         }
1835
1836 end:
1837         cleanup_all_probes();
1838         if (warn)
1839                 pr_cont("NG: Some tests are failed. Please check them.\n");
1840         else
1841                 pr_cont("OK\n");
1842         return 0;
1843 }
1844
1845 late_initcall(kprobe_trace_self_tests_init);
1846
1847 #endif