kernel/trace/trace_probe.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Common code for probe-based Dynamic events.
   4  *
   5  * This code was copied from kernel/trace/trace_kprobe.c written by
   6  * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
   7  *
   8  * Updates to make this generic:
   9  * Copyright (C) IBM Corporation, 2010-2011
  10  * Author:     Srikar Dronamraju
  11  */
  12 #define pr_fmt(fmt)     "trace_probe: " fmt
  13
  14 #include <linux/bpf.h>
  15 #include "trace_btf.h"
  16
  17 #include "trace_probe.h"
  18
  19 #undef C
  20 #define C(a, b)         b
  21
  22 static const char *trace_probe_err_text[] = { ERRORS };
  23
  24 static const char *reserved_field_names[] = {
  25         "common_type",
  26         "common_flags",
  27         "common_preempt_count",
  28         "common_pid",
  29         "common_tgid",
  30         FIELD_STRING_IP,
  31         FIELD_STRING_RETIP,
  32         FIELD_STRING_FUNC,
  33 };
  34
  35 /* Printing  in basic type function template */
  36 #define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt)                  \
  37 int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, void *data, void *ent)\
  38 {                                                                       \
  39         trace_seq_printf(s, fmt, *(type *)data);                        \
  40         return !trace_seq_has_overflowed(s);                            \
  41 }                                                                       \
  42 const char PRINT_TYPE_FMT_NAME(tname)[] = fmt;
  43
  44 DEFINE_BASIC_PRINT_TYPE_FUNC(u8,  u8,  "%u")
  45 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u")
  46 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u")
  47 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu")
  48 DEFINE_BASIC_PRINT_TYPE_FUNC(s8,  s8,  "%d")
  49 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")
  50 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")
  51 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")
  52 DEFINE_BASIC_PRINT_TYPE_FUNC(x8,  u8,  "0x%x")
  53 DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
  54 DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
  55 DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")
  56 DEFINE_BASIC_PRINT_TYPE_FUNC(char, u8, "'%c'")
  57
  58 int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent)
  59 {
  60         trace_seq_printf(s, "%pS", (void *)*(unsigned long *)data);
  61         return !trace_seq_has_overflowed(s);
  62 }
  63 const char PRINT_TYPE_FMT_NAME(symbol)[] = "%pS";
  64
  65 /* Print type function for string type */
  66 int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent)
  67 {
  68         int len = *(u32 *)data >> 16;
  69
  70         if (!len)
  71                 trace_seq_puts(s, FAULT_STRING);
  72         else
  73                 trace_seq_printf(s, "\"%s\"",
  74                                  (const char *)get_loc_data(data, ent));
  75         return !trace_seq_has_overflowed(s);
  76 }
  77
  78 const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
  79
  80 /* Fetch type information table */
  81 static const struct fetch_type probe_fetch_types[] = {
  82         /* Special types */
  83         __ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1, 1,
  84                             "__data_loc char[]"),
  85         __ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1, 1,
  86                             "__data_loc char[]"),
  87         __ASSIGN_FETCH_TYPE("symstr", string, string, sizeof(u32), 1, 1,
  88                             "__data_loc char[]"),
  89         /* Basic types */
  90         ASSIGN_FETCH_TYPE(u8,  u8,  0),
  91         ASSIGN_FETCH_TYPE(u16, u16, 0),
  92         ASSIGN_FETCH_TYPE(u32, u32, 0),
  93         ASSIGN_FETCH_TYPE(u64, u64, 0),
  94         ASSIGN_FETCH_TYPE(s8,  u8,  1),
  95         ASSIGN_FETCH_TYPE(s16, u16, 1),
  96         ASSIGN_FETCH_TYPE(s32, u32, 1),
  97         ASSIGN_FETCH_TYPE(s64, u64, 1),
  98         ASSIGN_FETCH_TYPE_ALIAS(x8,  u8,  u8,  0),
  99         ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
 100         ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
 101         ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
 102         ASSIGN_FETCH_TYPE_ALIAS(char, u8, u8,  0),
 103         ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0),
 104
 105         ASSIGN_FETCH_TYPE_END
 106 };
 107
 108 static const struct fetch_type *find_fetch_type(const char *type, unsigned long flags)
 109 {
 110         int i;
 111
 112         /* Reject the symbol/symstr for uprobes */
 113         if (type && (flags & TPARG_FL_USER) &&
 114             (!strcmp(type, "symbol") || !strcmp(type, "symstr")))
 115                 return NULL;
 116
 117         if (!type)
 118                 type = DEFAULT_FETCH_TYPE_STR;
 119
 120         /* Special case: bitfield */
 121         if (*type == 'b') {
 122                 unsigned long bs;
 123
 124                 type = strchr(type, '/');
 125                 if (!type)
 126                         goto fail;
 127
 128                 type++;
 129                 if (kstrtoul(type, 0, &bs))
 130                         goto fail;
 131
 132                 switch (bs) {
 133                 case 8:
 134                         return find_fetch_type("u8", flags);
 135                 case 16:
 136                         return find_fetch_type("u16", flags);
 137                 case 32:
 138                         return find_fetch_type("u32", flags);
 139                 case 64:
 140                         return find_fetch_type("u64", flags);
 141                 default:
 142                         goto fail;
 143                 }
 144         }
 145
 146         for (i = 0; probe_fetch_types[i].name; i++) {
 147                 if (strcmp(type, probe_fetch_types[i].name) == 0)
 148                         return &probe_fetch_types[i];
 149         }
 150
 151 fail:
 152         return NULL;
 153 }
 154
 155 static struct trace_probe_log trace_probe_log;
 156
 157 void trace_probe_log_init(const char *subsystem, int argc, const char **argv)
 158 {
 159         trace_probe_log.subsystem = subsystem;
 160         trace_probe_log.argc = argc;
 161         trace_probe_log.argv = argv;
 162         trace_probe_log.index = 0;
 163 }
 164
 165 void trace_probe_log_clear(void)
 166 {
 167         memset(&trace_probe_log, 0, sizeof(trace_probe_log));
 168 }
 169
 170 void trace_probe_log_set_index(int index)
 171 {
 172         trace_probe_log.index = index;
 173 }
 174
 175 void __trace_probe_log_err(int offset, int err_type)
 176 {
 177         char *command, *p;
 178         int i, len = 0, pos = 0;
 179
 180         if (!trace_probe_log.argv)
 181                 return;
 182
 183         /* Recalculate the length and allocate buffer */
 184         for (i = 0; i < trace_probe_log.argc; i++) {
 185                 if (i == trace_probe_log.index)
 186                         pos = len;
 187                 len += strlen(trace_probe_log.argv[i]) + 1;
 188         }
 189         command = kzalloc(len, GFP_KERNEL);
 190         if (!command)
 191                 return;
 192
 193         if (trace_probe_log.index >= trace_probe_log.argc) {
 194                 /**
 195                  * Set the error position is next to the last arg + space.
 196                  * Note that len includes the terminal null and the cursor
 197                  * appears at pos + 1.
 198                  */
 199                 pos = len;
 200                 offset = 0;
 201         }
 202
 203         /* And make a command string from argv array */
 204         p = command;
 205         for (i = 0; i < trace_probe_log.argc; i++) {
 206                 len = strlen(trace_probe_log.argv[i]);
 207                 strcpy(p, trace_probe_log.argv[i]);
 208                 p[len] = ' ';
 209                 p += len + 1;
 210         }
 211         *(p - 1) = '\0';
 212
 213         tracing_log_err(NULL, trace_probe_log.subsystem, command,
 214                         trace_probe_err_text, err_type, pos + offset);
 215
 216         kfree(command);
 217 }
 218
 219 /* Split symbol and offset. */
 220 int traceprobe_split_symbol_offset(char *symbol, long *offset)
 221 {
 222         char *tmp;
 223         int ret;
 224
 225         if (!offset)
 226                 return -EINVAL;
 227
 228         tmp = strpbrk(symbol, "+-");
 229         if (tmp) {
 230                 ret = kstrtol(tmp, 0, offset);
 231                 if (ret)
 232                         return ret;
 233                 *tmp = '\0';
 234         } else
 235                 *offset = 0;
 236
 237         return 0;
 238 }
 239
 240 /* @buf must has MAX_EVENT_NAME_LEN size */
 241 int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
 242                                 char *buf, int offset)
 243 {
 244         const char *slash, *event = *pevent;
 245         int len;
 246
 247         slash = strchr(event, '/');
 248         if (!slash)
 249                 slash = strchr(event, '.');
 250
 251         if (slash) {
 252                 if (slash == event) {
 253                         trace_probe_log_err(offset, NO_GROUP_NAME);
 254                         return -EINVAL;
 255                 }
 256                 if (slash - event + 1 > MAX_EVENT_NAME_LEN) {
 257                         trace_probe_log_err(offset, GROUP_TOO_LONG);
 258                         return -EINVAL;
 259                 }
 260                 strscpy(buf, event, slash - event + 1);
 261                 if (!is_good_system_name(buf)) {
 262                         trace_probe_log_err(offset, BAD_GROUP_NAME);
 263                         return -EINVAL;
 264                 }
 265                 *pgroup = buf;
 266                 *pevent = slash + 1;
 267                 offset += slash - event + 1;
 268                 event = *pevent;
 269         }
 270         len = strlen(event);
 271         if (len == 0) {
 272                 if (slash) {
 273                         *pevent = NULL;
 274                         return 0;
 275                 }
 276                 trace_probe_log_err(offset, NO_EVENT_NAME);
 277                 return -EINVAL;
 278         } else if (len > MAX_EVENT_NAME_LEN) {
 279                 trace_probe_log_err(offset, EVENT_TOO_LONG);
 280                 return -EINVAL;
 281         }
 282         if (!is_good_name(event)) {
 283                 trace_probe_log_err(offset, BAD_EVENT_NAME);
 284                 return -EINVAL;
 285         }
 286         return 0;
 287 }
 288
 289 static int parse_trace_event_arg(char *arg, struct fetch_insn *code,
 290                                  struct traceprobe_parse_context *ctx)
 291 {
 292         struct ftrace_event_field *field;
 293         struct list_head *head;
 294
 295         head = trace_get_fields(ctx->event);
 296         list_for_each_entry(field, head, link) {
 297                 if (!strcmp(arg, field->name)) {
 298                         code->op = FETCH_OP_TP_ARG;
 299                         code->data = field;
 300                         return 0;
 301                 }
 302         }
 303         return -ENOENT;
 304 }
 305
 306 #ifdef CONFIG_PROBE_EVENTS_BTF_ARGS
 307
 308 static u32 btf_type_int(const struct btf_type *t)
 309 {
 310         return *(u32 *)(t + 1);
 311 }
 312
 313 static bool btf_type_is_char_ptr(struct btf *btf, const struct btf_type *type)
 314 {
 315         const struct btf_type *real_type;
 316         u32 intdata;
 317         s32 tid;
 318
 319         real_type = btf_type_skip_modifiers(btf, type->type, &tid);
 320         if (!real_type)
 321                 return false;
 322
 323         if (BTF_INFO_KIND(real_type->info) != BTF_KIND_INT)
 324                 return false;
 325
 326         intdata = btf_type_int(real_type);
 327         return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED)
 328                 && BTF_INT_BITS(intdata) == 8;
 329 }
 330
 331 static bool btf_type_is_char_array(struct btf *btf, const struct btf_type *type)
 332 {
 333         const struct btf_type *real_type;
 334         const struct btf_array *array;
 335         u32 intdata;
 336         s32 tid;
 337
 338         if (BTF_INFO_KIND(type->info) != BTF_KIND_ARRAY)
 339                 return false;
 340
 341         array = (const struct btf_array *)(type + 1);
 342
 343         real_type = btf_type_skip_modifiers(btf, array->type, &tid);
 344
 345         intdata = btf_type_int(real_type);
 346         return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED)
 347                 && BTF_INT_BITS(intdata) == 8;
 348 }
 349
 350 static int check_prepare_btf_string_fetch(char *typename,
 351                                 struct fetch_insn **pcode,
 352                                 struct traceprobe_parse_context *ctx)
 353 {
 354         struct btf *btf = ctx->btf;
 355
 356         if (!btf || !ctx->last_type)
 357                 return 0;
 358
 359         /* char [] does not need any change. */
 360         if (btf_type_is_char_array(btf, ctx->last_type))
 361                 return 0;
 362
 363         /* char * requires dereference the pointer. */
 364         if (btf_type_is_char_ptr(btf, ctx->last_type)) {
 365                 struct fetch_insn *code = *pcode + 1;
 366
 367                 if (code->op == FETCH_OP_END) {
 368                         trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
 369                         return -E2BIG;
 370                 }
 371                 if (typename[0] == 'u')
 372                         code->op = FETCH_OP_UDEREF;
 373                 else
 374                         code->op = FETCH_OP_DEREF;
 375                 code->offset = 0;
 376                 *pcode = code;
 377                 return 0;
 378         }
 379         /* Other types are not available for string */
 380         trace_probe_log_err(ctx->offset, BAD_TYPE4STR);
 381         return -EINVAL;
 382 }
 383
 384 static const char *fetch_type_from_btf_type(struct btf *btf,
 385                                         const struct btf_type *type,
 386                                         struct traceprobe_parse_context *ctx)
 387 {
 388         u32 intdata;
 389
 390         /* TODO: const char * could be converted as a string */
 391         switch (BTF_INFO_KIND(type->info)) {
 392         case BTF_KIND_ENUM:
 393                 /* enum is "int", so convert to "s32" */
 394                 return "s32";
 395         case BTF_KIND_ENUM64:
 396                 return "s64";
 397         case BTF_KIND_PTR:
 398                 /* pointer will be converted to "x??" */
 399                 if (IS_ENABLED(CONFIG_64BIT))
 400                         return "x64";
 401                 else
 402                         return "x32";
 403         case BTF_KIND_INT:
 404                 intdata = btf_type_int(type);
 405                 if (BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED) {
 406                         switch (BTF_INT_BITS(intdata)) {
 407                         case 8:
 408                                 return "s8";
 409                         case 16:
 410                                 return "s16";
 411                         case 32:
 412                                 return "s32";
 413                         case 64:
 414                                 return "s64";
 415                         }
 416                 } else {        /* unsigned */
 417                         switch (BTF_INT_BITS(intdata)) {
 418                         case 8:
 419                                 return "u8";
 420                         case 16:
 421                                 return "u16";
 422                         case 32:
 423                                 return "u32";
 424                         case 64:
 425                                 return "u64";
 426                         }
 427                         /* bitfield, size is encoded in the type */
 428                         ctx->last_bitsize = BTF_INT_BITS(intdata);
 429                         ctx->last_bitoffs += BTF_INT_OFFSET(intdata);
 430                         return "u64";
 431                 }
 432         }
 433         /* TODO: support other types */
 434
 435         return NULL;
 436 }
 437
 438 static int query_btf_context(struct traceprobe_parse_context *ctx)
 439 {
 440         const struct btf_param *param;
 441         const struct btf_type *type;
 442         struct btf *btf;
 443         s32 nr;
 444
 445         if (ctx->btf)
 446                 return 0;
 447
 448         if (!ctx->funcname)
 449                 return -EINVAL;
 450
 451         type = btf_find_func_proto(ctx->funcname, &btf);
 452         if (!type)
 453                 return -ENOENT;
 454
 455         ctx->btf = btf;
 456         ctx->proto = type;
 457
 458         /* ctx->params is optional, since func(void) will not have params. */
 459         nr = 0;
 460         param = btf_get_func_param(type, &nr);
 461         if (!IS_ERR_OR_NULL(param)) {
 462                 /* Hide the first 'data' argument of tracepoint */
 463                 if (ctx->flags & TPARG_FL_TPOINT) {
 464                         nr--;
 465                         param++;
 466                 }
 467         }
 468
 469         if (nr > 0) {
 470                 ctx->nr_params = nr;
 471                 ctx->params = param;
 472         } else {
 473                 ctx->nr_params = 0;
 474                 ctx->params = NULL;
 475         }
 476
 477         return 0;
 478 }
 479
 480 static void clear_btf_context(struct traceprobe_parse_context *ctx)
 481 {
 482         if (ctx->btf) {
 483                 btf_put(ctx->btf);
 484                 ctx->btf = NULL;
 485                 ctx->proto = NULL;
 486                 ctx->params = NULL;
 487                 ctx->nr_params = 0;
 488         }
 489 }
 490
 491 /* Return 1 if the field separater is arrow operator ('->') */
 492 static int split_next_field(char *varname, char **next_field,
 493                             struct traceprobe_parse_context *ctx)
 494 {
 495         char *field;
 496         int ret = 0;
 497
 498         field = strpbrk(varname, ".-");
 499         if (field) {
 500                 if (field[0] == '-' && field[1] == '>') {
 501                         field[0] = '\0';
 502                         field += 2;
 503                         ret = 1;
 504                 } else if (field[0] == '.') {
 505                         field[0] = '\0';
 506                         field += 1;
 507                 } else {
 508                         trace_probe_log_err(ctx->offset + field - varname, BAD_HYPHEN);
 509                         return -EINVAL;
 510                 }
 511                 *next_field = field;
 512         }
 513
 514         return ret;
 515 }
 516
 517 /*
 518  * Parse the field of data structure. The @type must be a pointer type
 519  * pointing the target data structure type.
 520  */
 521 static int parse_btf_field(char *fieldname, const struct btf_type *type,
 522                            struct fetch_insn **pcode, struct fetch_insn *end,
 523                            struct traceprobe_parse_context *ctx)
 524 {
 525         struct fetch_insn *code = *pcode;
 526         const struct btf_member *field;
 527         u32 bitoffs, anon_offs;
 528         char *next;
 529         int is_ptr;
 530         s32 tid;
 531
 532         do {
 533                 /* Outer loop for solving arrow operator ('->') */
 534                 if (BTF_INFO_KIND(type->info) != BTF_KIND_PTR) {
 535                         trace_probe_log_err(ctx->offset, NO_PTR_STRCT);
 536                         return -EINVAL;
 537                 }
 538                 /* Convert a struct pointer type to a struct type */
 539                 type = btf_type_skip_modifiers(ctx->btf, type->type, &tid);
 540                 if (!type) {
 541                         trace_probe_log_err(ctx->offset, BAD_BTF_TID);
 542                         return -EINVAL;
 543                 }
 544
 545                 bitoffs = 0;
 546                 do {
 547                         /* Inner loop for solving dot operator ('.') */
 548                         next = NULL;
 549                         is_ptr = split_next_field(fieldname, &next, ctx);
 550                         if (is_ptr < 0)
 551                                 return is_ptr;
 552
 553                         anon_offs = 0;
 554                         field = btf_find_struct_member(ctx->btf, type, fieldname,
 555                                                        &anon_offs);
 556                         if (!field) {
 557                                 trace_probe_log_err(ctx->offset, NO_BTF_FIELD);
 558                                 return -ENOENT;
 559                         }
 560                         /* Add anonymous structure/union offset */
 561                         bitoffs += anon_offs;
 562
 563                         /* Accumulate the bit-offsets of the dot-connected fields */
 564                         if (btf_type_kflag(type)) {
 565                                 bitoffs += BTF_MEMBER_BIT_OFFSET(field->offset);
 566                                 ctx->last_bitsize = BTF_MEMBER_BITFIELD_SIZE(field->offset);
 567                         } else {
 568                                 bitoffs += field->offset;
 569                                 ctx->last_bitsize = 0;
 570                         }
 571
 572                         type = btf_type_skip_modifiers(ctx->btf, field->type, &tid);
 573                         if (!type) {
 574                                 trace_probe_log_err(ctx->offset, BAD_BTF_TID);
 575                                 return -EINVAL;
 576                         }
 577
 578                         ctx->offset += next - fieldname;
 579                         fieldname = next;
 580                 } while (!is_ptr && fieldname);
 581
 582                 if (++code == end) {
 583                         trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
 584                         return -EINVAL;
 585                 }
 586                 code->op = FETCH_OP_DEREF;      /* TODO: user deref support */
 587                 code->offset = bitoffs / 8;
 588                 *pcode = code;
 589
 590                 ctx->last_bitoffs = bitoffs % 8;
 591                 ctx->last_type = type;
 592         } while (fieldname);
 593
 594         return 0;
 595 }
 596
 597 static int __store_entry_arg(struct trace_probe *tp, int argnum);
 598
 599 static int parse_btf_arg(char *varname,
 600                          struct fetch_insn **pcode, struct fetch_insn *end,
 601                          struct traceprobe_parse_context *ctx)
 602 {
 603         struct fetch_insn *code = *pcode;
 604         const struct btf_param *params;
 605         const struct btf_type *type;
 606         char *field = NULL;
 607         int i, is_ptr, ret;
 608         u32 tid;
 609
 610         if (WARN_ON_ONCE(!ctx->funcname))
 611                 return -EINVAL;
 612
 613         is_ptr = split_next_field(varname, &field, ctx);
 614         if (is_ptr < 0)
 615                 return is_ptr;
 616         if (!is_ptr && field) {
 617                 /* dot-connected field on an argument is not supported. */
 618                 trace_probe_log_err(ctx->offset + field - varname,
 619                                     NOSUP_DAT_ARG);
 620                 return -EOPNOTSUPP;
 621         }
 622
 623         if (ctx->flags & TPARG_FL_RETURN && !strcmp(varname, "$retval")) {
 624                 code->op = FETCH_OP_RETVAL;
 625                 /* Check whether the function return type is not void */
 626                 if (query_btf_context(ctx) == 0) {
 627                         if (ctx->proto->type == 0) {
 628                                 trace_probe_log_err(ctx->offset, NO_RETVAL);
 629                                 return -ENOENT;
 630                         }
 631                         tid = ctx->proto->type;
 632                         goto found;
 633                 }
 634                 if (field) {
 635                         trace_probe_log_err(ctx->offset + field - varname,
 636                                             NO_BTF_ENTRY);
 637                         return -ENOENT;
 638                 }
 639                 return 0;
 640         }
 641
 642         if (!ctx->btf) {
 643                 ret = query_btf_context(ctx);
 644                 if (ret < 0 || ctx->nr_params == 0) {
 645                         trace_probe_log_err(ctx->offset, NO_BTF_ENTRY);
 646                         return PTR_ERR(params);
 647                 }
 648         }
 649         params = ctx->params;
 650
 651         for (i = 0; i < ctx->nr_params; i++) {
 652                 const char *name = btf_name_by_offset(ctx->btf, params[i].name_off);
 653
 654                 if (name && !strcmp(name, varname)) {
 655                         if (tparg_is_function_entry(ctx->flags)) {
 656                                 code->op = FETCH_OP_ARG;
 657                                 if (ctx->flags & TPARG_FL_TPOINT)
 658                                         code->param = i + 1;
 659                                 else
 660                                         code->param = i;
 661                         } else if (tparg_is_function_return(ctx->flags)) {
 662                                 code->op = FETCH_OP_EDATA;
 663                                 ret = __store_entry_arg(ctx->tp, i);
 664                                 if (ret < 0) {
 665                                         /* internal error */
 666                                         return ret;
 667                                 }
 668                                 code->offset = ret;
 669                         }
 670                         tid = params[i].type;
 671                         goto found;
 672                 }
 673         }
 674         trace_probe_log_err(ctx->offset, NO_BTFARG);
 675         return -ENOENT;
 676
 677 found:
 678         type = btf_type_skip_modifiers(ctx->btf, tid, &tid);
 679         if (!type) {
 680                 trace_probe_log_err(ctx->offset, BAD_BTF_TID);
 681                 return -EINVAL;
 682         }
 683         /* Initialize the last type information */
 684         ctx->last_type = type;
 685         ctx->last_bitoffs = 0;
 686         ctx->last_bitsize = 0;
 687         if (field) {
 688                 ctx->offset += field - varname;
 689                 return parse_btf_field(field, type, pcode, end, ctx);
 690         }
 691         return 0;
 692 }
 693
 694 static const struct fetch_type *find_fetch_type_from_btf_type(
 695                                         struct traceprobe_parse_context *ctx)
 696 {
 697         struct btf *btf = ctx->btf;
 698         const char *typestr = NULL;
 699
 700         if (btf && ctx->last_type)
 701                 typestr = fetch_type_from_btf_type(btf, ctx->last_type, ctx);
 702
 703         return find_fetch_type(typestr, ctx->flags);
 704 }
 705
 706 static int parse_btf_bitfield(struct fetch_insn **pcode,
 707                               struct traceprobe_parse_context *ctx)
 708 {
 709         struct fetch_insn *code = *pcode;
 710
 711         if ((ctx->last_bitsize % 8 == 0) && ctx->last_bitoffs == 0)
 712                 return 0;
 713
 714         code++;
 715         if (code->op != FETCH_OP_NOP) {
 716                 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
 717                 return -EINVAL;
 718         }
 719         *pcode = code;
 720
 721         code->op = FETCH_OP_MOD_BF;
 722         code->lshift = 64 - (ctx->last_bitsize + ctx->last_bitoffs);
 723         code->rshift = 64 - ctx->last_bitsize;
 724         code->basesize = 64 / 8;
 725         return 0;
 726 }
 727
 728 #else
 729 static void clear_btf_context(struct traceprobe_parse_context *ctx)
 730 {
 731         ctx->btf = NULL;
 732 }
 733
 734 static int query_btf_context(struct traceprobe_parse_context *ctx)
 735 {
 736         return -EOPNOTSUPP;
 737 }
 738
 739 static int parse_btf_arg(char *varname,
 740                          struct fetch_insn **pcode, struct fetch_insn *end,
 741                          struct traceprobe_parse_context *ctx)
 742 {
 743         trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
 744         return -EOPNOTSUPP;
 745 }
 746
 747 static int parse_btf_bitfield(struct fetch_insn **pcode,
 748                               struct traceprobe_parse_context *ctx)
 749 {
 750         trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
 751         return -EOPNOTSUPP;
 752 }
 753
 754 #define find_fetch_type_from_btf_type(ctx)              \
 755         find_fetch_type(NULL, ctx->flags)
 756
 757 static int check_prepare_btf_string_fetch(char *typename,
 758                                 struct fetch_insn **pcode,
 759                                 struct traceprobe_parse_context *ctx)
 760 {
 761         return 0;
 762 }
 763
 764 #endif
 765
 766 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
 767
 768 static int __store_entry_arg(struct trace_probe *tp, int argnum)
 769 {
 770         struct probe_entry_arg *earg = tp->entry_arg;
 771         bool match = false;
 772         int i, offset;
 773
 774         if (!earg) {
 775                 earg = kzalloc(sizeof(*tp->entry_arg), GFP_KERNEL);
 776                 if (!earg)
 777                         return -ENOMEM;
 778                 earg->size = 2 * tp->nr_args + 1;
 779                 earg->code = kcalloc(earg->size, sizeof(struct fetch_insn),
 780                                      GFP_KERNEL);
 781                 if (!earg->code) {
 782                         kfree(earg);
 783                         return -ENOMEM;
 784                 }
 785                 /* Fill the code buffer with 'end' to simplify it */
 786                 for (i = 0; i < earg->size; i++)
 787                         earg->code[i].op = FETCH_OP_END;
 788                 tp->entry_arg = earg;
 789         }
 790
 791         offset = 0;
 792         for (i = 0; i < earg->size - 1; i++) {
 793                 switch (earg->code[i].op) {
 794                 case FETCH_OP_END:
 795                         earg->code[i].op = FETCH_OP_ARG;
 796                         earg->code[i].param = argnum;
 797                         earg->code[i + 1].op = FETCH_OP_ST_EDATA;
 798                         earg->code[i + 1].offset = offset;
 799                         return offset;
 800                 case FETCH_OP_ARG:
 801                         match = (earg->code[i].param == argnum);
 802                         break;
 803                 case FETCH_OP_ST_EDATA:
 804                         offset = earg->code[i].offset;
 805                         if (match)
 806                                 return offset;
 807                         offset += sizeof(unsigned long);
 808                         break;
 809                 default:
 810                         break;
 811                 }
 812         }
 813         return -ENOSPC;
 814 }
 815
 816 int traceprobe_get_entry_data_size(struct trace_probe *tp)
 817 {
 818         struct probe_entry_arg *earg = tp->entry_arg;
 819         int i, size = 0;
 820
 821         if (!earg)
 822                 return 0;
 823
 824         for (i = 0; i < earg->size; i++) {
 825                 switch (earg->code[i].op) {
 826                 case FETCH_OP_END:
 827                         goto out;
 828                 case FETCH_OP_ST_EDATA:
 829                         size = earg->code[i].offset + sizeof(unsigned long);
 830                         break;
 831                 default:
 832                         break;
 833                 }
 834         }
 835 out:
 836         return size;
 837 }
 838
 839 void store_trace_entry_data(void *edata, struct trace_probe *tp, struct pt_regs *regs)
 840 {
 841         struct probe_entry_arg *earg = tp->entry_arg;
 842         unsigned long val = 0;
 843         int i;
 844
 845         if (!earg)
 846                 return;
 847
 848         for (i = 0; i < earg->size; i++) {
 849                 struct fetch_insn *code = &earg->code[i];
 850
 851                 switch (code->op) {
 852                 case FETCH_OP_ARG:
 853                         val = regs_get_kernel_argument(regs, code->param);
 854                         break;
 855                 case FETCH_OP_ST_EDATA:
 856                         *(unsigned long *)((unsigned long)edata + code->offset) = val;
 857                         break;
 858                 case FETCH_OP_END:
 859                         goto end;
 860                 default:
 861                         break;
 862                 }
 863         }
 864 end:
 865         return;
 866 }
 867 NOKPROBE_SYMBOL(store_trace_entry_data)
 868 #endif
 869
 870 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
 871
 872 /* Parse $vars. @orig_arg points '$', which syncs to @ctx->offset */
 873 static int parse_probe_vars(char *orig_arg, const struct fetch_type *t,
 874                             struct fetch_insn **pcode,
 875                             struct fetch_insn *end,
 876                             struct traceprobe_parse_context *ctx)
 877 {
 878         struct fetch_insn *code = *pcode;
 879         int err = TP_ERR_BAD_VAR;
 880         char *arg = orig_arg + 1;
 881         unsigned long param;
 882         int ret = 0;
 883         int len;
 884
 885         if (ctx->flags & TPARG_FL_TEVENT) {
 886                 if (code->data)
 887                         return -EFAULT;
 888                 ret = parse_trace_event_arg(arg, code, ctx);
 889                 if (!ret)
 890                         return 0;
 891                 if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
 892                         code->op = FETCH_OP_COMM;
 893                         return 0;
 894                 }
 895                 /* backward compatibility */
 896                 ctx->offset = 0;
 897                 goto inval;
 898         }
 899
 900         if (str_has_prefix(arg, "retval")) {
 901                 if (!(ctx->flags & TPARG_FL_RETURN)) {
 902                         err = TP_ERR_RETVAL_ON_PROBE;
 903                         goto inval;
 904                 }
 905                 if (!(ctx->flags & TPARG_FL_KERNEL) ||
 906                     !IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
 907                         code->op = FETCH_OP_RETVAL;
 908                         return 0;
 909                 }
 910                 return parse_btf_arg(orig_arg, pcode, end, ctx);
 911         }
 912
 913         len = str_has_prefix(arg, "stack");
 914         if (len) {
 915
 916                 if (arg[len] == '\0') {
 917                         code->op = FETCH_OP_STACKP;
 918                         return 0;
 919                 }
 920
 921                 if (isdigit(arg[len])) {
 922                         ret = kstrtoul(arg + len, 10, &param);
 923                         if (ret)
 924                                 goto inval;
 925
 926                         if ((ctx->flags & TPARG_FL_KERNEL) &&
 927                             param > PARAM_MAX_STACK) {
 928                                 err = TP_ERR_BAD_STACK_NUM;
 929                                 goto inval;
 930                         }
 931                         code->op = FETCH_OP_STACK;
 932                         code->param = (unsigned int)param;
 933                         return 0;
 934                 }
 935                 goto inval;
 936         }
 937
 938         if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
 939                 code->op = FETCH_OP_COMM;
 940                 return 0;
 941         }
 942
 943 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
 944         len = str_has_prefix(arg, "arg");
 945         if (len) {
 946                 ret = kstrtoul(arg + len, 10, &param);
 947                 if (ret)
 948                         goto inval;
 949
 950                 if (!param || param > PARAM_MAX_STACK) {
 951                         err = TP_ERR_BAD_ARG_NUM;
 952                         goto inval;
 953                 }
 954                 param--; /* argN starts from 1, but internal arg[N] starts from 0 */
 955
 956                 if (tparg_is_function_entry(ctx->flags)) {
 957                         code->op = FETCH_OP_ARG;
 958                         code->param = (unsigned int)param;
 959                         /*
 960                          * The tracepoint probe will probe a stub function, and the
 961                          * first parameter of the stub is a dummy and should be ignored.
 962                          */
 963                         if (ctx->flags & TPARG_FL_TPOINT)
 964                                 code->param++;
 965                 } else if (tparg_is_function_return(ctx->flags)) {
 966                         /* function entry argument access from return probe */
 967                         ret = __store_entry_arg(ctx->tp, param);
 968                         if (ret < 0)    /* This error should be an internal error */
 969                                 return ret;
 970
 971                         code->op = FETCH_OP_EDATA;
 972                         code->offset = ret;
 973                 } else {
 974                         err = TP_ERR_NOFENTRY_ARGS;
 975                         goto inval;
 976                 }
 977                 return 0;
 978         }
 979 #endif
 980
 981 inval:
 982         __trace_probe_log_err(ctx->offset, err);
 983         return -EINVAL;
 984 }
 985
 986 static int str_to_immediate(char *str, unsigned long *imm)
 987 {
 988         if (isdigit(str[0]))
 989                 return kstrtoul(str, 0, imm);
 990         else if (str[0] == '-')
 991                 return kstrtol(str, 0, (long *)imm);
 992         else if (str[0] == '+')
 993                 return kstrtol(str + 1, 0, (long *)imm);
 994         return -EINVAL;
 995 }
 996
 997 static int __parse_imm_string(char *str, char **pbuf, int offs)
 998 {
 999         size_t len = strlen(str);
1000
1001         if (str[len - 1] != '"') {
1002                 trace_probe_log_err(offs + len, IMMSTR_NO_CLOSE);
1003                 return -EINVAL;
1004         }
1005         *pbuf = kstrndup(str, len - 1, GFP_KERNEL);
1006         if (!*pbuf)
1007                 return -ENOMEM;
1008         return 0;
1009 }
1010
1011 /* Recursive argument parser */
1012 static int
1013 parse_probe_arg(char *arg, const struct fetch_type *type,
1014                 struct fetch_insn **pcode, struct fetch_insn *end,
1015                 struct traceprobe_parse_context *ctx)
1016 {
1017         struct fetch_insn *code = *pcode;
1018         unsigned long param;
1019         int deref = FETCH_OP_DEREF;
1020         long offset = 0;
1021         char *tmp;
1022         int ret = 0;
1023
1024         switch (arg[0]) {
1025         case '$':
1026                 ret = parse_probe_vars(arg, type, pcode, end, ctx);
1027                 break;
1028
1029         case '%':       /* named register */
1030                 if (ctx->flags & (TPARG_FL_TEVENT | TPARG_FL_FPROBE)) {
1031                         /* eprobe and fprobe do not handle registers */
1032                         trace_probe_log_err(ctx->offset, BAD_VAR);
1033                         break;
1034                 }
1035                 ret = regs_query_register_offset(arg + 1);
1036                 if (ret >= 0) {
1037                         code->op = FETCH_OP_REG;
1038                         code->param = (unsigned int)ret;
1039                         ret = 0;
1040                 } else
1041                         trace_probe_log_err(ctx->offset, BAD_REG_NAME);
1042                 break;
1043
1044         case '@':       /* memory, file-offset or symbol */
1045                 if (isdigit(arg[1])) {
1046                         ret = kstrtoul(arg + 1, 0, &param);
1047                         if (ret) {
1048                                 trace_probe_log_err(ctx->offset, BAD_MEM_ADDR);
1049                                 break;
1050                         }
1051                         /* load address */
1052                         code->op = FETCH_OP_IMM;
1053                         code->immediate = param;
1054                 } else if (arg[1] == '+') {
1055                         /* kprobes don't support file offsets */
1056                         if (ctx->flags & TPARG_FL_KERNEL) {
1057                                 trace_probe_log_err(ctx->offset, FILE_ON_KPROBE);
1058                                 return -EINVAL;
1059                         }
1060                         ret = kstrtol(arg + 2, 0, &offset);
1061                         if (ret) {
1062                                 trace_probe_log_err(ctx->offset, BAD_FILE_OFFS);
1063                                 break;
1064                         }
1065
1066                         code->op = FETCH_OP_FOFFS;
1067                         code->immediate = (unsigned long)offset;  // imm64?
1068                 } else {
1069                         /* uprobes don't support symbols */
1070                         if (!(ctx->flags & TPARG_FL_KERNEL)) {
1071                                 trace_probe_log_err(ctx->offset, SYM_ON_UPROBE);
1072                                 return -EINVAL;
1073                         }
1074                         /* Preserve symbol for updating */
1075                         code->op = FETCH_NOP_SYMBOL;
1076                         code->data = kstrdup(arg + 1, GFP_KERNEL);
1077                         if (!code->data)
1078                                 return -ENOMEM;
1079                         if (++code == end) {
1080                                 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1081                                 return -EINVAL;
1082                         }
1083                         code->op = FETCH_OP_IMM;
1084                         code->immediate = 0;
1085                 }
1086                 /* These are fetching from memory */
1087                 if (++code == end) {
1088                         trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1089                         return -EINVAL;
1090                 }
1091                 *pcode = code;
1092                 code->op = FETCH_OP_DEREF;
1093                 code->offset = offset;
1094                 break;
1095
1096         case '+':       /* deref memory */
1097         case '-':
1098                 if (arg[1] == 'u') {
1099                         deref = FETCH_OP_UDEREF;
1100                         arg[1] = arg[0];
1101                         arg++;
1102                 }
1103                 if (arg[0] == '+')
1104                         arg++;  /* Skip '+', because kstrtol() rejects it. */
1105                 tmp = strchr(arg, '(');
1106                 if (!tmp) {
1107                         trace_probe_log_err(ctx->offset, DEREF_NEED_BRACE);
1108                         return -EINVAL;
1109                 }
1110                 *tmp = '\0';
1111                 ret = kstrtol(arg, 0, &offset);
1112                 if (ret) {
1113                         trace_probe_log_err(ctx->offset, BAD_DEREF_OFFS);
1114                         break;
1115                 }
1116                 ctx->offset += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0);
1117                 arg = tmp + 1;
1118                 tmp = strrchr(arg, ')');
1119                 if (!tmp) {
1120                         trace_probe_log_err(ctx->offset + strlen(arg),
1121                                             DEREF_OPEN_BRACE);
1122                         return -EINVAL;
1123                 } else {
1124                         const struct fetch_type *t2 = find_fetch_type(NULL, ctx->flags);
1125                         int cur_offs = ctx->offset;
1126
1127                         *tmp = '\0';
1128                         ret = parse_probe_arg(arg, t2, &code, end, ctx);
1129                         if (ret)
1130                                 break;
1131                         ctx->offset = cur_offs;
1132                         if (code->op == FETCH_OP_COMM ||
1133                             code->op == FETCH_OP_DATA) {
1134                                 trace_probe_log_err(ctx->offset, COMM_CANT_DEREF);
1135                                 return -EINVAL;
1136                         }
1137                         if (++code == end) {
1138                                 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1139                                 return -EINVAL;
1140                         }
1141                         *pcode = code;
1142
1143                         code->op = deref;
1144                         code->offset = offset;
1145                         /* Reset the last type if used */
1146                         ctx->last_type = NULL;
1147                 }
1148                 break;
1149         case '\\':      /* Immediate value */
1150                 if (arg[1] == '"') {    /* Immediate string */
1151                         ret = __parse_imm_string(arg + 2, &tmp, ctx->offset + 2);
1152                         if (ret)
1153                                 break;
1154                         code->op = FETCH_OP_DATA;
1155                         code->data = tmp;
1156                 } else {
1157                         ret = str_to_immediate(arg + 1, &code->immediate);
1158                         if (ret)
1159                                 trace_probe_log_err(ctx->offset + 1, BAD_IMM);
1160                         else
1161                                 code->op = FETCH_OP_IMM;
1162                 }
1163                 break;
1164         default:
1165                 if (isalpha(arg[0]) || arg[0] == '_') { /* BTF variable */
1166                         if (!tparg_is_function_entry(ctx->flags) &&
1167                             !tparg_is_function_return(ctx->flags)) {
1168                                 trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
1169                                 return -EINVAL;
1170                         }
1171                         ret = parse_btf_arg(arg, pcode, end, ctx);
1172                         break;
1173                 }
1174         }
1175         if (!ret && code->op == FETCH_OP_NOP) {
1176                 /* Parsed, but do not find fetch method */
1177                 trace_probe_log_err(ctx->offset, BAD_FETCH_ARG);
1178                 ret = -EINVAL;
1179         }
1180         return ret;
1181 }
1182
1183 #define BYTES_TO_BITS(nb)       ((BITS_PER_LONG * (nb)) / sizeof(long))
1184
1185 /* Bitfield type needs to be parsed into a fetch function */
1186 static int __parse_bitfield_probe_arg(const char *bf,
1187                                       const struct fetch_type *t,
1188                                       struct fetch_insn **pcode)
1189 {
1190         struct fetch_insn *code = *pcode;
1191         unsigned long bw, bo;
1192         char *tail;
1193
1194         if (*bf != 'b')
1195                 return 0;
1196
1197         bw = simple_strtoul(bf + 1, &tail, 0);  /* Use simple one */
1198
1199         if (bw == 0 || *tail != '@')
1200                 return -EINVAL;
1201
1202         bf = tail + 1;
1203         bo = simple_strtoul(bf, &tail, 0);
1204
1205         if (tail == bf || *tail != '/')
1206                 return -EINVAL;
1207         code++;
1208         if (code->op != FETCH_OP_NOP)
1209                 return -EINVAL;
1210         *pcode = code;
1211
1212         code->op = FETCH_OP_MOD_BF;
1213         code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
1214         code->rshift = BYTES_TO_BITS(t->size) - bw;
1215         code->basesize = t->size;
1216
1217         return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
1218 }
1219
1220 /* Split type part from @arg and return it. */
1221 static char *parse_probe_arg_type(char *arg, struct probe_arg *parg,
1222                                   struct traceprobe_parse_context *ctx)
1223 {
1224         char *t = NULL, *t2, *t3;
1225         int offs;
1226
1227         t = strchr(arg, ':');
1228         if (t) {
1229                 *t++ = '\0';
1230                 t2 = strchr(t, '[');
1231                 if (t2) {
1232                         *t2++ = '\0';
1233                         t3 = strchr(t2, ']');
1234                         if (!t3) {
1235                                 offs = t2 + strlen(t2) - arg;
1236
1237                                 trace_probe_log_err(ctx->offset + offs,
1238                                                     ARRAY_NO_CLOSE);
1239                                 return ERR_PTR(-EINVAL);
1240                         } else if (t3[1] != '\0') {
1241                                 trace_probe_log_err(ctx->offset + t3 + 1 - arg,
1242                                                     BAD_ARRAY_SUFFIX);
1243                                 return ERR_PTR(-EINVAL);
1244                         }
1245                         *t3 = '\0';
1246                         if (kstrtouint(t2, 0, &parg->count) || !parg->count) {
1247                                 trace_probe_log_err(ctx->offset + t2 - arg,
1248                                                     BAD_ARRAY_NUM);
1249                                 return ERR_PTR(-EINVAL);
1250                         }
1251                         if (parg->count > MAX_ARRAY_LEN) {
1252                                 trace_probe_log_err(ctx->offset + t2 - arg,
1253                                                     ARRAY_TOO_BIG);
1254                                 return ERR_PTR(-EINVAL);
1255                         }
1256                 }
1257         }
1258         offs = t ? t - arg : 0;
1259
1260         /*
1261          * Since $comm and immediate string can not be dereferenced,
1262          * we can find those by strcmp. But ignore for eprobes.
1263          */
1264         if (!(ctx->flags & TPARG_FL_TEVENT) &&
1265             (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 ||
1266              strncmp(arg, "\\\"", 2) == 0)) {
1267                 /* The type of $comm must be "string", and not an array type. */
1268                 if (parg->count || (t && strcmp(t, "string"))) {
1269                         trace_probe_log_err(ctx->offset + offs, NEED_STRING_TYPE);
1270                         return ERR_PTR(-EINVAL);
1271                 }
1272                 parg->type = find_fetch_type("string", ctx->flags);
1273         } else
1274                 parg->type = find_fetch_type(t, ctx->flags);
1275
1276         if (!parg->type) {
1277                 trace_probe_log_err(ctx->offset + offs, BAD_TYPE);
1278                 return ERR_PTR(-EINVAL);
1279         }
1280
1281         return t;
1282 }
1283
1284 /* After parsing, adjust the fetch_insn according to the probe_arg */
1285 static int finalize_fetch_insn(struct fetch_insn *code,
1286                                struct probe_arg *parg,
1287                                char *type,
1288                                int type_offset,
1289                                struct traceprobe_parse_context *ctx)
1290 {
1291         struct fetch_insn *scode;
1292         int ret;
1293
1294         /* Store operation */
1295         if (parg->type->is_string) {
1296                 /* Check bad combination of the type and the last fetch_insn. */
1297                 if (!strcmp(parg->type->name, "symstr")) {
1298                         if (code->op != FETCH_OP_REG && code->op != FETCH_OP_STACK &&
1299                             code->op != FETCH_OP_RETVAL && code->op != FETCH_OP_ARG &&
1300                             code->op != FETCH_OP_DEREF && code->op != FETCH_OP_TP_ARG) {
1301                                 trace_probe_log_err(ctx->offset + type_offset,
1302                                                     BAD_SYMSTRING);
1303                                 return -EINVAL;
1304                         }
1305                 } else {
1306                         if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF &&
1307                             code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM &&
1308                             code->op != FETCH_OP_DATA && code->op != FETCH_OP_TP_ARG) {
1309                                 trace_probe_log_err(ctx->offset + type_offset,
1310                                                     BAD_STRING);
1311                                 return -EINVAL;
1312                         }
1313                 }
1314
1315                 if (!strcmp(parg->type->name, "symstr") ||
1316                     (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM ||
1317                      code->op == FETCH_OP_DATA) || code->op == FETCH_OP_TP_ARG ||
1318                      parg->count) {
1319                         /*
1320                          * IMM, DATA and COMM is pointing actual address, those
1321                          * must be kept, and if parg->count != 0, this is an
1322                          * array of string pointers instead of string address
1323                          * itself.
1324                          * For the symstr, it doesn't need to dereference, thus
1325                          * it just get the value.
1326                          */
1327                         code++;
1328                         if (code->op != FETCH_OP_NOP) {
1329                                 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1330                                 return -EINVAL;
1331                         }
1332                 }
1333
1334                 /* If op == DEREF, replace it with STRING */
1335                 if (!strcmp(parg->type->name, "ustring") ||
1336                     code->op == FETCH_OP_UDEREF)
1337                         code->op = FETCH_OP_ST_USTRING;
1338                 else if (!strcmp(parg->type->name, "symstr"))
1339                         code->op = FETCH_OP_ST_SYMSTR;
1340                 else
1341                         code->op = FETCH_OP_ST_STRING;
1342                 code->size = parg->type->size;
1343                 parg->dynamic = true;
1344         } else if (code->op == FETCH_OP_DEREF) {
1345                 code->op = FETCH_OP_ST_MEM;
1346                 code->size = parg->type->size;
1347         } else if (code->op == FETCH_OP_UDEREF) {
1348                 code->op = FETCH_OP_ST_UMEM;
1349                 code->size = parg->type->size;
1350         } else {
1351                 code++;
1352                 if (code->op != FETCH_OP_NOP) {
1353                         trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1354                         return -E2BIG;
1355                 }
1356                 code->op = FETCH_OP_ST_RAW;
1357                 code->size = parg->type->size;
1358         }
1359
1360         /* Save storing fetch_insn. */
1361         scode = code;
1362
1363         /* Modify operation */
1364         if (type != NULL) {
1365                 /* Bitfield needs a special fetch_insn. */
1366                 ret = __parse_bitfield_probe_arg(type, parg->type, &code);
1367                 if (ret) {
1368                         trace_probe_log_err(ctx->offset + type_offset, BAD_BITFIELD);
1369                         return ret;
1370                 }
1371         } else if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) &&
1372                    ctx->last_type) {
1373                 /* If user not specified the type, try parsing BTF bitfield. */
1374                 ret = parse_btf_bitfield(&code, ctx);
1375                 if (ret)
1376                         return ret;
1377         }
1378
1379         /* Loop(Array) operation */
1380         if (parg->count) {
1381                 if (scode->op != FETCH_OP_ST_MEM &&
1382                     scode->op != FETCH_OP_ST_STRING &&
1383                     scode->op != FETCH_OP_ST_USTRING) {
1384                         trace_probe_log_err(ctx->offset + type_offset, BAD_STRING);
1385                         return -EINVAL;
1386                 }
1387                 code++;
1388                 if (code->op != FETCH_OP_NOP) {
1389                         trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1390                         return -E2BIG;
1391                 }
1392                 code->op = FETCH_OP_LP_ARRAY;
1393                 code->param = parg->count;
1394         }
1395
1396         /* Finalize the fetch_insn array. */
1397         code++;
1398         code->op = FETCH_OP_END;
1399
1400         return 0;
1401 }
1402
1403 /* String length checking wrapper */
1404 static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
1405                                            struct probe_arg *parg,
1406                                            struct traceprobe_parse_context *ctx)
1407 {
1408         struct fetch_insn *code, *tmp = NULL;
1409         char *type, *arg;
1410         int ret, len;
1411
1412         len = strlen(argv);
1413         if (len > MAX_ARGSTR_LEN) {
1414                 trace_probe_log_err(ctx->offset, ARG_TOO_LONG);
1415                 return -E2BIG;
1416         } else if (len == 0) {
1417                 trace_probe_log_err(ctx->offset, NO_ARG_BODY);
1418                 return -EINVAL;
1419         }
1420
1421         arg = kstrdup(argv, GFP_KERNEL);
1422         if (!arg)
1423                 return -ENOMEM;
1424
1425         parg->comm = kstrdup(arg, GFP_KERNEL);
1426         if (!parg->comm) {
1427                 ret = -ENOMEM;
1428                 goto out;
1429         }
1430
1431         type = parse_probe_arg_type(arg, parg, ctx);
1432         if (IS_ERR(type)) {
1433                 ret = PTR_ERR(type);
1434                 goto out;
1435         }
1436
1437         code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL);
1438         if (!code) {
1439                 ret = -ENOMEM;
1440                 goto out;
1441         }
1442         code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
1443
1444         ctx->last_type = NULL;
1445         ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
1446                               ctx);
1447         if (ret < 0)
1448                 goto fail;
1449
1450         /* Update storing type if BTF is available */
1451         if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) &&
1452             ctx->last_type) {
1453                 if (!type) {
1454                         parg->type = find_fetch_type_from_btf_type(ctx);
1455                 } else if (strstr(type, "string")) {
1456                         ret = check_prepare_btf_string_fetch(type, &code, ctx);
1457                         if (ret)
1458                                 goto fail;
1459                 }
1460         }
1461         parg->offset = *size;
1462         *size += parg->type->size * (parg->count ?: 1);
1463
1464         if (parg->count) {
1465                 len = strlen(parg->type->fmttype) + 6;
1466                 parg->fmt = kmalloc(len, GFP_KERNEL);
1467                 if (!parg->fmt) {
1468                         ret = -ENOMEM;
1469                         goto fail;
1470                 }
1471                 snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
1472                          parg->count);
1473         }
1474
1475         ret = finalize_fetch_insn(code, parg, type, type ? type - arg : 0, ctx);
1476         if (ret < 0)
1477                 goto fail;
1478
1479         for (; code < tmp + FETCH_INSN_MAX; code++)
1480                 if (code->op == FETCH_OP_END)
1481                         break;
1482         /* Shrink down the code buffer */
1483         parg->code = kcalloc(code - tmp + 1, sizeof(*code), GFP_KERNEL);
1484         if (!parg->code)
1485                 ret = -ENOMEM;
1486         else
1487                 memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
1488
1489 fail:
1490         if (ret < 0) {
1491                 for (code = tmp; code < tmp + FETCH_INSN_MAX; code++)
1492                         if (code->op == FETCH_NOP_SYMBOL ||
1493                             code->op == FETCH_OP_DATA)
1494                                 kfree(code->data);
1495         }
1496         kfree(tmp);
1497 out:
1498         kfree(arg);
1499
1500         return ret;
1501 }
1502
1503 /* Return 1 if name is reserved or already used by another argument */
1504 static int traceprobe_conflict_field_name(const char *name,
1505                                           struct probe_arg *args, int narg)
1506 {
1507         int i;
1508
1509         for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
1510                 if (strcmp(reserved_field_names[i], name) == 0)
1511                         return 1;
1512
1513         for (i = 0; i < narg; i++)
1514                 if (strcmp(args[i].name, name) == 0)
1515                         return 1;
1516
1517         return 0;
1518 }
1519
1520 static char *generate_probe_arg_name(const char *arg, int idx)
1521 {
1522         char *name = NULL;
1523         const char *end;
1524
1525         /*
1526          * If argument name is omitted, try arg as a name (BTF variable)
1527          * or "argN".
1528          */
1529         if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
1530                 end = strchr(arg, ':');
1531                 if (!end)
1532                         end = arg + strlen(arg);
1533
1534                 name = kmemdup_nul(arg, end - arg, GFP_KERNEL);
1535                 if (!name || !is_good_name(name)) {
1536                         kfree(name);
1537                         name = NULL;
1538                 }
1539         }
1540
1541         if (!name)
1542                 name = kasprintf(GFP_KERNEL, "arg%d", idx + 1);
1543
1544         return name;
1545 }
1546
1547 int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *arg,
1548                                struct traceprobe_parse_context *ctx)
1549 {
1550         struct probe_arg *parg = &tp->args[i];
1551         const char *body;
1552
1553         ctx->tp = tp;
1554         body = strchr(arg, '=');
1555         if (body) {
1556                 if (body - arg > MAX_ARG_NAME_LEN) {
1557                         trace_probe_log_err(0, ARG_NAME_TOO_LONG);
1558                         return -EINVAL;
1559                 } else if (body == arg) {
1560                         trace_probe_log_err(0, NO_ARG_NAME);
1561                         return -EINVAL;
1562                 }
1563                 parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL);
1564                 body++;
1565         } else {
1566                 parg->name = generate_probe_arg_name(arg, i);
1567                 body = arg;
1568         }
1569         if (!parg->name)
1570                 return -ENOMEM;
1571
1572         if (!is_good_name(parg->name)) {
1573                 trace_probe_log_err(0, BAD_ARG_NAME);
1574                 return -EINVAL;
1575         }
1576         if (traceprobe_conflict_field_name(parg->name, tp->args, i)) {
1577                 trace_probe_log_err(0, USED_ARG_NAME);
1578                 return -EINVAL;
1579         }
1580         ctx->offset = body - arg;
1581         /* Parse fetch argument */
1582         return traceprobe_parse_probe_arg_body(body, &tp->size, parg, ctx);
1583 }
1584
1585 void traceprobe_free_probe_arg(struct probe_arg *arg)
1586 {
1587         struct fetch_insn *code = arg->code;
1588
1589         while (code && code->op != FETCH_OP_END) {
1590                 if (code->op == FETCH_NOP_SYMBOL ||
1591                     code->op == FETCH_OP_DATA)
1592                         kfree(code->data);
1593                 code++;
1594         }
1595         kfree(arg->code);
1596         kfree(arg->name);
1597         kfree(arg->comm);
1598         kfree(arg->fmt);
1599 }
1600
1601 static int argv_has_var_arg(int argc, const char *argv[], int *args_idx,
1602                             struct traceprobe_parse_context *ctx)
1603 {
1604         int i, found = 0;
1605
1606         for (i = 0; i < argc; i++)
1607                 if (str_has_prefix(argv[i], "$arg")) {
1608                         trace_probe_log_set_index(i + 2);
1609
1610                         if (!tparg_is_function_entry(ctx->flags) &&
1611                             !tparg_is_function_return(ctx->flags)) {
1612                                 trace_probe_log_err(0, NOFENTRY_ARGS);
1613                                 return -EINVAL;
1614                         }
1615
1616                         if (isdigit(argv[i][4])) {
1617                                 found = 1;
1618                                 continue;
1619                         }
1620
1621                         if (argv[i][4] != '*') {
1622                                 trace_probe_log_err(0, BAD_VAR);
1623                                 return -EINVAL;
1624                         }
1625
1626                         if (*args_idx >= 0 && *args_idx < argc) {
1627                                 trace_probe_log_err(0, DOUBLE_ARGS);
1628                                 return -EINVAL;
1629                         }
1630                         found = 1;
1631                         *args_idx = i;
1632                 }
1633
1634         return found;
1635 }
1636
1637 static int sprint_nth_btf_arg(int idx, const char *type,
1638                               char *buf, int bufsize,
1639                               struct traceprobe_parse_context *ctx)
1640 {
1641         const char *name;
1642         int ret;
1643
1644         if (idx >= ctx->nr_params) {
1645                 trace_probe_log_err(0, NO_BTFARG);
1646                 return -ENOENT;
1647         }
1648         name = btf_name_by_offset(ctx->btf, ctx->params[idx].name_off);
1649         if (!name) {
1650                 trace_probe_log_err(0, NO_BTF_ENTRY);
1651                 return -ENOENT;
1652         }
1653         ret = snprintf(buf, bufsize, "%s%s", name, type);
1654         if (ret >= bufsize) {
1655                 trace_probe_log_err(0, ARGS_2LONG);
1656                 return -E2BIG;
1657         }
1658         return ret;
1659 }
1660
1661 /* Return new_argv which must be freed after use */
1662 const char **traceprobe_expand_meta_args(int argc, const char *argv[],
1663                                          int *new_argc, char *buf, int bufsize,
1664                                          struct traceprobe_parse_context *ctx)
1665 {
1666         const struct btf_param *params = NULL;
1667         int i, j, n, used, ret, args_idx = -1;
1668         const char **new_argv = NULL;
1669
1670         ret = argv_has_var_arg(argc, argv, &args_idx, ctx);
1671         if (ret < 0)
1672                 return ERR_PTR(ret);
1673
1674         if (!ret) {
1675                 *new_argc = argc;
1676                 return NULL;
1677         }
1678
1679         ret = query_btf_context(ctx);
1680         if (ret < 0 || ctx->nr_params == 0) {
1681                 if (args_idx != -1) {
1682                         /* $arg* requires BTF info */
1683                         trace_probe_log_err(0, NOSUP_BTFARG);
1684                         return (const char **)params;
1685                 }
1686                 *new_argc = argc;
1687                 return NULL;
1688         }
1689
1690         if (args_idx >= 0)
1691                 *new_argc = argc + ctx->nr_params - 1;
1692         else
1693                 *new_argc = argc;
1694
1695         new_argv = kcalloc(*new_argc, sizeof(char *), GFP_KERNEL);
1696         if (!new_argv)
1697                 return ERR_PTR(-ENOMEM);
1698
1699         used = 0;
1700         for (i = 0, j = 0; i < argc; i++) {
1701                 trace_probe_log_set_index(i + 2);
1702                 if (i == args_idx) {
1703                         for (n = 0; n < ctx->nr_params; n++) {
1704                                 ret = sprint_nth_btf_arg(n, "", buf + used,
1705                                                          bufsize - used, ctx);
1706                                 if (ret < 0)
1707                                         goto error;
1708
1709                                 new_argv[j++] = buf + used;
1710                                 used += ret + 1;
1711                         }
1712                         continue;
1713                 }
1714
1715                 if (str_has_prefix(argv[i], "$arg")) {
1716                         char *type = NULL;
1717
1718                         n = simple_strtoul(argv[i] + 4, &type, 10);
1719                         if (type && !(*type == ':' || *type == '\0')) {
1720                                 trace_probe_log_err(0, BAD_VAR);
1721                                 ret = -ENOENT;
1722                                 goto error;
1723                         }
1724                         /* Note: $argN starts from $arg1 */
1725                         ret = sprint_nth_btf_arg(n - 1, type, buf + used,
1726                                                  bufsize - used, ctx);
1727                         if (ret < 0)
1728                                 goto error;
1729                         new_argv[j++] = buf + used;
1730                         used += ret + 1;
1731                 } else
1732                         new_argv[j++] = argv[i];
1733         }
1734
1735         return new_argv;
1736
1737 error:
1738         kfree(new_argv);
1739         return ERR_PTR(ret);
1740 }
1741
1742 void traceprobe_finish_parse(struct traceprobe_parse_context *ctx)
1743 {
1744         clear_btf_context(ctx);
1745 }
1746
1747 int traceprobe_update_arg(struct probe_arg *arg)
1748 {
1749         struct fetch_insn *code = arg->code;
1750         long offset;
1751         char *tmp;
1752         char c;
1753         int ret = 0;
1754
1755         while (code && code->op != FETCH_OP_END) {
1756                 if (code->op == FETCH_NOP_SYMBOL) {
1757                         if (code[1].op != FETCH_OP_IMM)
1758                                 return -EINVAL;
1759
1760                         tmp = strpbrk(code->data, "+-");
1761                         if (tmp)
1762                                 c = *tmp;
1763                         ret = traceprobe_split_symbol_offset(code->data,
1764                                                              &offset);
1765                         if (ret)
1766                                 return ret;
1767
1768                         code[1].immediate =
1769                                 (unsigned long)kallsyms_lookup_name(code->data);
1770                         if (tmp)
1771                                 *tmp = c;
1772                         if (!code[1].immediate)
1773                                 return -ENOENT;
1774                         code[1].immediate += offset;
1775                 }
1776                 code++;
1777         }
1778         return 0;
1779 }
1780
1781 /* When len=0, we just calculate the needed length */
1782 #define LEN_OR_ZERO (len ? len - pos : 0)
1783 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
1784                            enum probe_print_type ptype)
1785 {
1786         struct probe_arg *parg;
1787         int i, j;
1788         int pos = 0;
1789         const char *fmt, *arg;
1790
1791         switch (ptype) {
1792         case PROBE_PRINT_NORMAL:
1793                 fmt = "(%lx)";
1794                 arg = ", REC->" FIELD_STRING_IP;
1795                 break;
1796         case PROBE_PRINT_RETURN:
1797                 fmt = "(%lx <- %lx)";
1798                 arg = ", REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
1799                 break;
1800         case PROBE_PRINT_EVENT:
1801                 fmt = "";
1802                 arg = "";
1803                 break;
1804         default:
1805                 WARN_ON_ONCE(1);
1806                 return 0;
1807         }
1808
1809         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
1810
1811         for (i = 0; i < tp->nr_args; i++) {
1812                 parg = tp->args + i;
1813                 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name);
1814                 if (parg->count) {
1815                         pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s",
1816                                         parg->type->fmt);
1817                         for (j = 1; j < parg->count; j++)
1818                                 pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s",
1819                                                 parg->type->fmt);
1820                         pos += snprintf(buf + pos, LEN_OR_ZERO, "}");
1821                 } else
1822                         pos += snprintf(buf + pos, LEN_OR_ZERO, "%s",
1823                                         parg->type->fmt);
1824         }
1825
1826         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", arg);
1827
1828         for (i = 0; i < tp->nr_args; i++) {
1829                 parg = tp->args + i;
1830                 if (parg->count) {
1831                         if (parg->type->is_string)
1832                                 fmt = ", __get_str(%s[%d])";
1833                         else
1834                                 fmt = ", REC->%s[%d]";
1835                         for (j = 0; j < parg->count; j++)
1836                                 pos += snprintf(buf + pos, LEN_OR_ZERO,
1837                                                 fmt, parg->name, j);
1838                 } else {
1839                         if (parg->type->is_string)
1840                                 fmt = ", __get_str(%s)";
1841                         else
1842                                 fmt = ", REC->%s";
1843                         pos += snprintf(buf + pos, LEN_OR_ZERO,
1844                                         fmt, parg->name);
1845                 }
1846         }
1847
1848         /* return the length of print_fmt */
1849         return pos;
1850 }
1851 #undef LEN_OR_ZERO
1852
1853 int traceprobe_set_print_fmt(struct trace_probe *tp, enum probe_print_type ptype)
1854 {
1855         struct trace_event_call *call = trace_probe_event_call(tp);
1856         int len;
1857         char *print_fmt;
1858
1859         /* First: called with 0 length to calculate the needed length */
1860         len = __set_print_fmt(tp, NULL, 0, ptype);
1861         print_fmt = kmalloc(len + 1, GFP_KERNEL);
1862         if (!print_fmt)
1863                 return -ENOMEM;
1864
1865         /* Second: actually write the @print_fmt */
1866         __set_print_fmt(tp, print_fmt, len + 1, ptype);
1867         call->print_fmt = print_fmt;
1868
1869         return 0;
1870 }
1871
1872 int traceprobe_define_arg_fields(struct trace_event_call *event_call,
1873                                  size_t offset, struct trace_probe *tp)
1874 {
1875         int ret, i;
1876
1877         /* Set argument names as fields */
1878         for (i = 0; i < tp->nr_args; i++) {
1879                 struct probe_arg *parg = &tp->args[i];
1880                 const char *fmt = parg->type->fmttype;
1881                 int size = parg->type->size;
1882
1883                 if (parg->fmt)
1884                         fmt = parg->fmt;
1885                 if (parg->count)
1886                         size *= parg->count;
1887                 ret = trace_define_field(event_call, fmt, parg->name,
1888                                          offset + parg->offset, size,
1889                                          parg->type->is_signed,
1890                                          FILTER_OTHER);
1891                 if (ret)
1892                         return ret;
1893         }
1894         return 0;
1895 }
1896
1897 static void trace_probe_event_free(struct trace_probe_event *tpe)
1898 {
1899         kfree(tpe->class.system);
1900         kfree(tpe->call.name);
1901         kfree(tpe->call.print_fmt);
1902         kfree(tpe);
1903 }
1904
1905 int trace_probe_append(struct trace_probe *tp, struct trace_probe *to)
1906 {
1907         if (trace_probe_has_sibling(tp))
1908                 return -EBUSY;
1909
1910         list_del_init(&tp->list);
1911         trace_probe_event_free(tp->event);
1912
1913         tp->event = to->event;
1914         list_add_tail(&tp->list, trace_probe_probe_list(to));
1915
1916         return 0;
1917 }
1918
1919 void trace_probe_unlink(struct trace_probe *tp)
1920 {
1921         list_del_init(&tp->list);
1922         if (list_empty(trace_probe_probe_list(tp)))
1923                 trace_probe_event_free(tp->event);
1924         tp->event = NULL;
1925 }
1926
1927 void trace_probe_cleanup(struct trace_probe *tp)
1928 {
1929         int i;
1930
1931         for (i = 0; i < tp->nr_args; i++)
1932                 traceprobe_free_probe_arg(&tp->args[i]);
1933
1934         if (tp->entry_arg) {
1935                 kfree(tp->entry_arg->code);
1936                 kfree(tp->entry_arg);
1937                 tp->entry_arg = NULL;
1938         }
1939
1940         if (tp->event)
1941                 trace_probe_unlink(tp);
1942 }
1943
1944 int trace_probe_init(struct trace_probe *tp, const char *event,
1945                      const char *group, bool alloc_filter, int nargs)
1946 {
1947         struct trace_event_call *call;
1948         size_t size = sizeof(struct trace_probe_event);
1949         int ret = 0;
1950
1951         if (!event || !group)
1952                 return -EINVAL;
1953
1954         if (alloc_filter)
1955                 size += sizeof(struct trace_uprobe_filter);
1956
1957         tp->event = kzalloc(size, GFP_KERNEL);
1958         if (!tp->event)
1959                 return -ENOMEM;
1960
1961         INIT_LIST_HEAD(&tp->event->files);
1962         INIT_LIST_HEAD(&tp->event->class.fields);
1963         INIT_LIST_HEAD(&tp->event->probes);
1964         INIT_LIST_HEAD(&tp->list);
1965         list_add(&tp->list, &tp->event->probes);
1966
1967         call = trace_probe_event_call(tp);
1968         call->class = &tp->event->class;
1969         call->name = kstrdup(event, GFP_KERNEL);
1970         if (!call->name) {
1971                 ret = -ENOMEM;
1972                 goto error;
1973         }
1974
1975         tp->event->class.system = kstrdup(group, GFP_KERNEL);
1976         if (!tp->event->class.system) {
1977                 ret = -ENOMEM;
1978                 goto error;
1979         }
1980
1981         tp->nr_args = nargs;
1982         /* Make sure pointers in args[] are NULL */
1983         if (nargs)
1984                 memset(tp->args, 0, sizeof(tp->args[0]) * nargs);
1985
1986         return 0;
1987
1988 error:
1989         trace_probe_cleanup(tp);
1990         return ret;
1991 }
1992
1993 static struct trace_event_call *
1994 find_trace_event_call(const char *system, const char *event_name)
1995 {
1996         struct trace_event_call *tp_event;
1997         const char *name;
1998
1999         list_for_each_entry(tp_event, &ftrace_events, list) {
2000                 if (!tp_event->class->system ||
2001                     strcmp(system, tp_event->class->system))
2002                         continue;
2003                 name = trace_event_name(tp_event);
2004                 if (!name || strcmp(event_name, name))
2005                         continue;
2006                 return tp_event;
2007         }
2008
2009         return NULL;
2010 }
2011
2012 int trace_probe_register_event_call(struct trace_probe *tp)
2013 {
2014         struct trace_event_call *call = trace_probe_event_call(tp);
2015         int ret;
2016
2017         lockdep_assert_held(&event_mutex);
2018
2019         if (find_trace_event_call(trace_probe_group_name(tp),
2020                                   trace_probe_name(tp)))
2021                 return -EEXIST;
2022
2023         ret = register_trace_event(&call->event);
2024         if (!ret)
2025                 return -ENODEV;
2026
2027         ret = trace_add_event_call(call);
2028         if (ret)
2029                 unregister_trace_event(&call->event);
2030
2031         return ret;
2032 }
2033
2034 int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file)
2035 {
2036         struct event_file_link *link;
2037
2038         link = kmalloc(sizeof(*link), GFP_KERNEL);
2039         if (!link)
2040                 return -ENOMEM;
2041
2042         link->file = file;
2043         INIT_LIST_HEAD(&link->list);
2044         list_add_tail_rcu(&link->list, &tp->event->files);
2045         trace_probe_set_flag(tp, TP_FLAG_TRACE);
2046         return 0;
2047 }
2048
2049 struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
2050                                                   struct trace_event_file *file)
2051 {
2052         struct event_file_link *link;
2053
2054         trace_probe_for_each_link(link, tp) {
2055                 if (link->file == file)
2056                         return link;
2057         }
2058
2059         return NULL;
2060 }
2061
2062 int trace_probe_remove_file(struct trace_probe *tp,
2063                             struct trace_event_file *file)
2064 {
2065         struct event_file_link *link;
2066
2067         link = trace_probe_get_file_link(tp, file);
2068         if (!link)
2069                 return -ENOENT;
2070
2071         list_del_rcu(&link->list);
2072         kvfree_rcu_mightsleep(link);
2073
2074         if (list_empty(&tp->event->files))
2075                 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
2076
2077         return 0;
2078 }
2079
2080 /*
2081  * Return the smallest index of different type argument (start from 1).
2082  * If all argument types and name are same, return 0.
2083  */
2084 int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)
2085 {
2086         int i;
2087
2088         /* In case of more arguments */
2089         if (a->nr_args < b->nr_args)
2090                 return a->nr_args + 1;
2091         if (a->nr_args > b->nr_args)
2092                 return b->nr_args + 1;
2093
2094         for (i = 0; i < a->nr_args; i++) {
2095                 if ((b->nr_args <= i) ||
2096                     ((a->args[i].type != b->args[i].type) ||
2097                      (a->args[i].count != b->args[i].count) ||
2098                      strcmp(a->args[i].name, b->args[i].name)))
2099                         return i + 1;
2100         }
2101
2102         return 0;
2103 }
2104
2105 bool trace_probe_match_command_args(struct trace_probe *tp,
2106                                     int argc, const char **argv)
2107 {
2108         char buf[MAX_ARGSTR_LEN + 1];
2109         int i;
2110
2111         if (tp->nr_args < argc)
2112                 return false;
2113
2114         for (i = 0; i < argc; i++) {
2115                 snprintf(buf, sizeof(buf), "%s=%s",
2116                          tp->args[i].name, tp->args[i].comm);
2117                 if (strcmp(buf, argv[i]))
2118                         return false;
2119         }
2120         return true;
2121 }
2122
2123 int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **))
2124 {
2125         int argc = 0, ret = 0;
2126         char **argv;
2127
2128         argv = argv_split(GFP_KERNEL, raw_command, &argc);
2129         if (!argv)
2130                 return -ENOMEM;
2131
2132         if (argc)
2133                 ret = createfn(argc, (const char **)argv);
2134
2135         argv_free(argv);
2136
2137         return ret;
2138 }
2139
2140 int trace_probe_print_args(struct trace_seq *s, struct probe_arg *args, int nr_args,
2141                  u8 *data, void *field)
2142 {
2143         void *p;
2144         int i, j;
2145
2146         for (i = 0; i < nr_args; i++) {
2147                 struct probe_arg *a = args + i;
2148
2149                 trace_seq_printf(s, " %s=", a->name);
2150                 if (likely(!a->count)) {
2151                         if (!a->type->print(s, data + a->offset, field))
2152                                 return -ENOMEM;
2153                         continue;
2154                 }
2155                 trace_seq_putc(s, '{');
2156                 p = data + a->offset;
2157                 for (j = 0; j < a->count; j++) {
2158                         if (!a->type->print(s, p, field))
2159                                 return -ENOMEM;
2160                         trace_seq_putc(s, j == a->count - 1 ? '}' : ',');
2161                         p += a->type->size;
2162                 }
2163         }
2164         return 0;
2165 }