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