kernel/trace/bpf_trace.c

   1 /* Copyright (c) 2011-2015 PLUMgrid, http://plumgrid.com
   2  * Copyright (c) 2016 Facebook
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of version 2 of the GNU General Public
   6  * License as published by the Free Software Foundation.
   7  */
   8 #include <linux/kernel.h>
   9 #include <linux/types.h>
  10 #include <linux/slab.h>
  11 #include <linux/bpf.h>
  12 #include <linux/bpf_perf_event.h>
  13 #include <linux/filter.h>
  14 #include <linux/uaccess.h>
  15 #include <linux/ctype.h>
  16 #include "trace.h"
  17
  18 /**
  19  * trace_call_bpf - invoke BPF program
  20  * @prog: BPF program
  21  * @ctx: opaque context pointer
  22  *
  23  * kprobe handlers execute BPF programs via this helper.
  24  * Can be used from static tracepoints in the future.
  25  *
  26  * Return: BPF programs always return an integer which is interpreted by
  27  * kprobe handler as:
  28  * 0 - return from kprobe (event is filtered out)
  29  * 1 - store kprobe event into ring buffer
  30  * Other values are reserved and currently alias to 1
  31  */
  32 unsigned int trace_call_bpf(struct bpf_prog *prog, void *ctx)
  33 {
  34         unsigned int ret;
  35
  36         if (in_nmi()) /* not supported yet */
  37                 return 1;
  38
  39         preempt_disable();
  40
  41         if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) {
  42                 /*
  43                  * since some bpf program is already running on this cpu,
  44                  * don't call into another bpf program (same or different)
  45                  * and don't send kprobe event into ring-buffer,
  46                  * so return zero here
  47                  */
  48                 ret = 0;
  49                 goto out;
  50         }
  51
  52         rcu_read_lock();
  53         ret = BPF_PROG_RUN(prog, ctx);
  54         rcu_read_unlock();
  55
  56  out:
  57         __this_cpu_dec(bpf_prog_active);
  58         preempt_enable();
  59
  60         return ret;
  61 }
  62 EXPORT_SYMBOL_GPL(trace_call_bpf);
  63
  64 BPF_CALL_3(bpf_probe_read, void *, dst, u32, size, const void *, unsafe_ptr)
  65 {
  66         int ret;
  67
  68         ret = probe_kernel_read(dst, unsafe_ptr, size);
  69         if (unlikely(ret < 0))
  70                 memset(dst, 0, size);
  71
  72         return ret;
  73 }
  74
  75 static const struct bpf_func_proto bpf_probe_read_proto = {
  76         .func           = bpf_probe_read,
  77         .gpl_only       = true,
  78         .ret_type       = RET_INTEGER,
  79         .arg1_type      = ARG_PTR_TO_UNINIT_MEM,
  80         .arg2_type      = ARG_CONST_SIZE,
  81         .arg3_type      = ARG_ANYTHING,
  82 };
  83
  84 BPF_CALL_3(bpf_probe_write_user, void *, unsafe_ptr, const void *, src,
  85            u32, size)
  86 {
  87         /*
  88          * Ensure we're in user context which is safe for the helper to
  89          * run. This helper has no business in a kthread.
  90          *
  91          * access_ok() should prevent writing to non-user memory, but in
  92          * some situations (nommu, temporary switch, etc) access_ok() does
  93          * not provide enough validation, hence the check on KERNEL_DS.
  94          */
  95
  96         if (unlikely(in_interrupt() ||
  97                      current->flags & (PF_KTHREAD | PF_EXITING)))
  98                 return -EPERM;
  99         if (unlikely(uaccess_kernel()))
 100                 return -EPERM;
 101         if (!access_ok(VERIFY_WRITE, unsafe_ptr, size))
 102                 return -EPERM;
 103
 104         return probe_kernel_write(unsafe_ptr, src, size);
 105 }
 106
 107 static const struct bpf_func_proto bpf_probe_write_user_proto = {
 108         .func           = bpf_probe_write_user,
 109         .gpl_only       = true,
 110         .ret_type       = RET_INTEGER,
 111         .arg1_type      = ARG_ANYTHING,
 112         .arg2_type      = ARG_PTR_TO_MEM,
 113         .arg3_type      = ARG_CONST_SIZE,
 114 };
 115
 116 static const struct bpf_func_proto *bpf_get_probe_write_proto(void)
 117 {
 118         pr_warn_ratelimited("%s[%d] is installing a program with bpf_probe_write_user helper that may corrupt user memory!",
 119                             current->comm, task_pid_nr(current));
 120
 121         return &bpf_probe_write_user_proto;
 122 }
 123
 124 /*
 125  * Only limited trace_printk() conversion specifiers allowed:
 126  * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %s
 127  */
 128 BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1,
 129            u64, arg2, u64, arg3)
 130 {
 131         bool str_seen = false;
 132         int mod[3] = {};
 133         int fmt_cnt = 0;
 134         u64 unsafe_addr;
 135         char buf[64];
 136         int i;
 137
 138         /*
 139          * bpf_check()->check_func_arg()->check_stack_boundary()
 140          * guarantees that fmt points to bpf program stack,
 141          * fmt_size bytes of it were initialized and fmt_size > 0
 142          */
 143         if (fmt[--fmt_size] != 0)
 144                 return -EINVAL;
 145
 146         /* check format string for allowed specifiers */
 147         for (i = 0; i < fmt_size; i++) {
 148                 if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i]))
 149                         return -EINVAL;
 150
 151                 if (fmt[i] != '%')
 152                         continue;
 153
 154                 if (fmt_cnt >= 3)
 155                         return -EINVAL;
 156
 157                 /* fmt[i] != 0 && fmt[last] == 0, so we can access fmt[i + 1] */
 158                 i++;
 159                 if (fmt[i] == 'l') {
 160                         mod[fmt_cnt]++;
 161                         i++;
 162                 } else if (fmt[i] == 'p' || fmt[i] == 's') {
 163                         mod[fmt_cnt]++;
 164                         i++;
 165                         if (!isspace(fmt[i]) && !ispunct(fmt[i]) && fmt[i] != 0)
 166                                 return -EINVAL;
 167                         fmt_cnt++;
 168                         if (fmt[i - 1] == 's') {
 169                                 if (str_seen)
 170                                         /* allow only one '%s' per fmt string */
 171                                         return -EINVAL;
 172                                 str_seen = true;
 173
 174                                 switch (fmt_cnt) {
 175                                 case 1:
 176                                         unsafe_addr = arg1;
 177                                         arg1 = (long) buf;
 178                                         break;
 179                                 case 2:
 180                                         unsafe_addr = arg2;
 181                                         arg2 = (long) buf;
 182                                         break;
 183                                 case 3:
 184                                         unsafe_addr = arg3;
 185                                         arg3 = (long) buf;
 186                                         break;
 187                                 }
 188                                 buf[0] = 0;
 189                                 strncpy_from_unsafe(buf,
 190                                                     (void *) (long) unsafe_addr,
 191                                                     sizeof(buf));
 192                         }
 193                         continue;
 194                 }
 195
 196                 if (fmt[i] == 'l') {
 197                         mod[fmt_cnt]++;
 198                         i++;
 199                 }
 200
 201                 if (fmt[i] != 'i' && fmt[i] != 'd' &&
 202                     fmt[i] != 'u' && fmt[i] != 'x')
 203                         return -EINVAL;
 204                 fmt_cnt++;
 205         }
 206
 207         return __trace_printk(1/* fake ip will not be printed */, fmt,
 208                               mod[0] == 2 ? arg1 : mod[0] == 1 ? (long) arg1 : (u32) arg1,
 209                               mod[1] == 2 ? arg2 : mod[1] == 1 ? (long) arg2 : (u32) arg2,
 210                               mod[2] == 2 ? arg3 : mod[2] == 1 ? (long) arg3 : (u32) arg3);
 211 }
 212
 213 static const struct bpf_func_proto bpf_trace_printk_proto = {
 214         .func           = bpf_trace_printk,
 215         .gpl_only       = true,
 216         .ret_type       = RET_INTEGER,
 217         .arg1_type      = ARG_PTR_TO_MEM,
 218         .arg2_type      = ARG_CONST_SIZE,
 219 };
 220
 221 const struct bpf_func_proto *bpf_get_trace_printk_proto(void)
 222 {
 223         /*
 224          * this program might be calling bpf_trace_printk,
 225          * so allocate per-cpu printk buffers
 226          */
 227         trace_printk_init_buffers();
 228
 229         return &bpf_trace_printk_proto;
 230 }
 231
 232 BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags)
 233 {
 234         struct bpf_array *array = container_of(map, struct bpf_array, map);
 235         unsigned int cpu = smp_processor_id();
 236         u64 index = flags & BPF_F_INDEX_MASK;
 237         struct bpf_event_entry *ee;
 238         u64 value = 0;
 239         int err;
 240
 241         if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
 242                 return -EINVAL;
 243         if (index == BPF_F_CURRENT_CPU)
 244                 index = cpu;
 245         if (unlikely(index >= array->map.max_entries))
 246                 return -E2BIG;
 247
 248         ee = READ_ONCE(array->ptrs[index]);
 249         if (!ee)
 250                 return -ENOENT;
 251
 252         err = perf_event_read_local(ee->event, &value);
 253         /*
 254          * this api is ugly since we miss [-22..-2] range of valid
 255          * counter values, but that's uapi
 256          */
 257         if (err)
 258                 return err;
 259         return value;
 260 }
 261
 262 static const struct bpf_func_proto bpf_perf_event_read_proto = {
 263         .func           = bpf_perf_event_read,
 264         .gpl_only       = true,
 265         .ret_type       = RET_INTEGER,
 266         .arg1_type      = ARG_CONST_MAP_PTR,
 267         .arg2_type      = ARG_ANYTHING,
 268 };
 269
 270 static DEFINE_PER_CPU(struct perf_sample_data, bpf_sd);
 271
 272 static __always_inline u64
 273 __bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map,
 274                         u64 flags, struct perf_raw_record *raw)
 275 {
 276         struct bpf_array *array = container_of(map, struct bpf_array, map);
 277         struct perf_sample_data *sd = this_cpu_ptr(&bpf_sd);
 278         unsigned int cpu = smp_processor_id();
 279         u64 index = flags & BPF_F_INDEX_MASK;
 280         struct bpf_event_entry *ee;
 281         struct perf_event *event;
 282
 283         if (index == BPF_F_CURRENT_CPU)
 284                 index = cpu;
 285         if (unlikely(index >= array->map.max_entries))
 286                 return -E2BIG;
 287
 288         ee = READ_ONCE(array->ptrs[index]);
 289         if (!ee)
 290                 return -ENOENT;
 291
 292         event = ee->event;
 293         if (unlikely(event->attr.type != PERF_TYPE_SOFTWARE ||
 294                      event->attr.config != PERF_COUNT_SW_BPF_OUTPUT))
 295                 return -EINVAL;
 296
 297         if (unlikely(event->oncpu != cpu))
 298                 return -EOPNOTSUPP;
 299
 300         perf_sample_data_init(sd, 0, 0);
 301         sd->raw = raw;
 302         perf_event_output(event, sd, regs);
 303         return 0;
 304 }
 305
 306 BPF_CALL_5(bpf_perf_event_output, struct pt_regs *, regs, struct bpf_map *, map,
 307            u64, flags, void *, data, u64, size)
 308 {
 309         struct perf_raw_record raw = {
 310                 .frag = {
 311                         .size = size,
 312                         .data = data,
 313                 },
 314         };
 315
 316         if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
 317                 return -EINVAL;
 318
 319         return __bpf_perf_event_output(regs, map, flags, &raw);
 320 }
 321
 322 static const struct bpf_func_proto bpf_perf_event_output_proto = {
 323         .func           = bpf_perf_event_output,
 324         .gpl_only       = true,
 325         .ret_type       = RET_INTEGER,
 326         .arg1_type      = ARG_PTR_TO_CTX,
 327         .arg2_type      = ARG_CONST_MAP_PTR,
 328         .arg3_type      = ARG_ANYTHING,
 329         .arg4_type      = ARG_PTR_TO_MEM,
 330         .arg5_type      = ARG_CONST_SIZE,
 331 };
 332
 333 static DEFINE_PER_CPU(struct pt_regs, bpf_pt_regs);
 334
 335 u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
 336                      void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)
 337 {
 338         struct pt_regs *regs = this_cpu_ptr(&bpf_pt_regs);
 339         struct perf_raw_frag frag = {
 340                 .copy           = ctx_copy,
 341                 .size           = ctx_size,
 342                 .data           = ctx,
 343         };
 344         struct perf_raw_record raw = {
 345                 .frag = {
 346                         {
 347                                 .next   = ctx_size ? &frag : NULL,
 348                         },
 349                         .size   = meta_size,
 350                         .data   = meta,
 351                 },
 352         };
 353
 354         perf_fetch_caller_regs(regs);
 355
 356         return __bpf_perf_event_output(regs, map, flags, &raw);
 357 }
 358
 359 BPF_CALL_0(bpf_get_current_task)
 360 {
 361         return (long) current;
 362 }
 363
 364 static const struct bpf_func_proto bpf_get_current_task_proto = {
 365         .func           = bpf_get_current_task,
 366         .gpl_only       = true,
 367         .ret_type       = RET_INTEGER,
 368 };
 369
 370 BPF_CALL_2(bpf_current_task_under_cgroup, struct bpf_map *, map, u32, idx)
 371 {
 372         struct bpf_array *array = container_of(map, struct bpf_array, map);
 373         struct cgroup *cgrp;
 374
 375         if (unlikely(in_interrupt()))
 376                 return -EINVAL;
 377         if (unlikely(idx >= array->map.max_entries))
 378                 return -E2BIG;
 379
 380         cgrp = READ_ONCE(array->ptrs[idx]);
 381         if (unlikely(!cgrp))
 382                 return -EAGAIN;
 383
 384         return task_under_cgroup_hierarchy(current, cgrp);
 385 }
 386
 387 static const struct bpf_func_proto bpf_current_task_under_cgroup_proto = {
 388         .func           = bpf_current_task_under_cgroup,
 389         .gpl_only       = false,
 390         .ret_type       = RET_INTEGER,
 391         .arg1_type      = ARG_CONST_MAP_PTR,
 392         .arg2_type      = ARG_ANYTHING,
 393 };
 394
 395 BPF_CALL_3(bpf_probe_read_str, void *, dst, u32, size,
 396            const void *, unsafe_ptr)
 397 {
 398         int ret;
 399
 400         /*
 401          * The strncpy_from_unsafe() call will likely not fill the entire
 402          * buffer, but that's okay in this circumstance as we're probing
 403          * arbitrary memory anyway similar to bpf_probe_read() and might
 404          * as well probe the stack. Thus, memory is explicitly cleared
 405          * only in error case, so that improper users ignoring return
 406          * code altogether don't copy garbage; otherwise length of string
 407          * is returned that can be used for bpf_perf_event_output() et al.
 408          */
 409         ret = strncpy_from_unsafe(dst, unsafe_ptr, size);
 410         if (unlikely(ret < 0))
 411                 memset(dst, 0, size);
 412
 413         return ret;
 414 }
 415
 416 static const struct bpf_func_proto bpf_probe_read_str_proto = {
 417         .func           = bpf_probe_read_str,
 418         .gpl_only       = true,
 419         .ret_type       = RET_INTEGER,
 420         .arg1_type      = ARG_PTR_TO_UNINIT_MEM,
 421         .arg2_type      = ARG_CONST_SIZE,
 422         .arg3_type      = ARG_ANYTHING,
 423 };
 424
 425 static const struct bpf_func_proto *tracing_func_proto(enum bpf_func_id func_id)
 426 {
 427         switch (func_id) {
 428         case BPF_FUNC_map_lookup_elem:
 429                 return &bpf_map_lookup_elem_proto;
 430         case BPF_FUNC_map_update_elem:
 431                 return &bpf_map_update_elem_proto;
 432         case BPF_FUNC_map_delete_elem:
 433                 return &bpf_map_delete_elem_proto;
 434         case BPF_FUNC_probe_read:
 435                 return &bpf_probe_read_proto;
 436         case BPF_FUNC_ktime_get_ns:
 437                 return &bpf_ktime_get_ns_proto;
 438         case BPF_FUNC_tail_call:
 439                 return &bpf_tail_call_proto;
 440         case BPF_FUNC_get_current_pid_tgid:
 441                 return &bpf_get_current_pid_tgid_proto;
 442         case BPF_FUNC_get_current_task:
 443                 return &bpf_get_current_task_proto;
 444         case BPF_FUNC_get_current_uid_gid:
 445                 return &bpf_get_current_uid_gid_proto;
 446         case BPF_FUNC_get_current_comm:
 447                 return &bpf_get_current_comm_proto;
 448         case BPF_FUNC_trace_printk:
 449                 return bpf_get_trace_printk_proto();
 450         case BPF_FUNC_get_smp_processor_id:
 451                 return &bpf_get_smp_processor_id_proto;
 452         case BPF_FUNC_get_numa_node_id:
 453                 return &bpf_get_numa_node_id_proto;
 454         case BPF_FUNC_perf_event_read:
 455                 return &bpf_perf_event_read_proto;
 456         case BPF_FUNC_probe_write_user:
 457                 return bpf_get_probe_write_proto();
 458         case BPF_FUNC_current_task_under_cgroup:
 459                 return &bpf_current_task_under_cgroup_proto;
 460         case BPF_FUNC_get_prandom_u32:
 461                 return &bpf_get_prandom_u32_proto;
 462         case BPF_FUNC_probe_read_str:
 463                 return &bpf_probe_read_str_proto;
 464         default:
 465                 return NULL;
 466         }
 467 }
 468
 469 static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func_id)
 470 {
 471         switch (func_id) {
 472         case BPF_FUNC_perf_event_output:
 473                 return &bpf_perf_event_output_proto;
 474         case BPF_FUNC_get_stackid:
 475                 return &bpf_get_stackid_proto;
 476         default:
 477                 return tracing_func_proto(func_id);
 478         }
 479 }
 480
 481 /* bpf+kprobe programs can access fields of 'struct pt_regs' */
 482 static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type type,
 483                                         struct bpf_insn_access_aux *info)
 484 {
 485         if (off < 0 || off >= sizeof(struct pt_regs))
 486                 return false;
 487         if (type != BPF_READ)
 488                 return false;
 489         if (off % size != 0)
 490                 return false;
 491         /*
 492          * Assertion for 32 bit to make sure last 8 byte access
 493          * (BPF_DW) to the last 4 byte member is disallowed.
 494          */
 495         if (off + size > sizeof(struct pt_regs))
 496                 return false;
 497
 498         return true;
 499 }
 500
 501 const struct bpf_verifier_ops kprobe_prog_ops = {
 502         .get_func_proto  = kprobe_prog_func_proto,
 503         .is_valid_access = kprobe_prog_is_valid_access,
 504 };
 505
 506 BPF_CALL_5(bpf_perf_event_output_tp, void *, tp_buff, struct bpf_map *, map,
 507            u64, flags, void *, data, u64, size)
 508 {
 509         struct pt_regs *regs = *(struct pt_regs **)tp_buff;
 510
 511         /*
 512          * r1 points to perf tracepoint buffer where first 8 bytes are hidden
 513          * from bpf program and contain a pointer to 'struct pt_regs'. Fetch it
 514          * from there and call the same bpf_perf_event_output() helper inline.
 515          */
 516         return ____bpf_perf_event_output(regs, map, flags, data, size);
 517 }
 518
 519 static const struct bpf_func_proto bpf_perf_event_output_proto_tp = {
 520         .func           = bpf_perf_event_output_tp,
 521         .gpl_only       = true,
 522         .ret_type       = RET_INTEGER,
 523         .arg1_type      = ARG_PTR_TO_CTX,
 524         .arg2_type      = ARG_CONST_MAP_PTR,
 525         .arg3_type      = ARG_ANYTHING,
 526         .arg4_type      = ARG_PTR_TO_MEM,
 527         .arg5_type      = ARG_CONST_SIZE,
 528 };
 529
 530 BPF_CALL_3(bpf_get_stackid_tp, void *, tp_buff, struct bpf_map *, map,
 531            u64, flags)
 532 {
 533         struct pt_regs *regs = *(struct pt_regs **)tp_buff;
 534
 535         /*
 536          * Same comment as in bpf_perf_event_output_tp(), only that this time
 537          * the other helper's function body cannot be inlined due to being
 538          * external, thus we need to call raw helper function.
 539          */
 540         return bpf_get_stackid((unsigned long) regs, (unsigned long) map,
 541                                flags, 0, 0);
 542 }
 543
 544 static const struct bpf_func_proto bpf_get_stackid_proto_tp = {
 545         .func           = bpf_get_stackid_tp,
 546         .gpl_only       = true,
 547         .ret_type       = RET_INTEGER,
 548         .arg1_type      = ARG_PTR_TO_CTX,
 549         .arg2_type      = ARG_CONST_MAP_PTR,
 550         .arg3_type      = ARG_ANYTHING,
 551 };
 552
 553 static const struct bpf_func_proto *tp_prog_func_proto(enum bpf_func_id func_id)
 554 {
 555         switch (func_id) {
 556         case BPF_FUNC_perf_event_output:
 557                 return &bpf_perf_event_output_proto_tp;
 558         case BPF_FUNC_get_stackid:
 559                 return &bpf_get_stackid_proto_tp;
 560         default:
 561                 return tracing_func_proto(func_id);
 562         }
 563 }
 564
 565 static bool tp_prog_is_valid_access(int off, int size, enum bpf_access_type type,
 566                                     struct bpf_insn_access_aux *info)
 567 {
 568         if (off < sizeof(void *) || off >= PERF_MAX_TRACE_SIZE)
 569                 return false;
 570         if (type != BPF_READ)
 571                 return false;
 572         if (off % size != 0)
 573                 return false;
 574
 575         BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(__u64));
 576         return true;
 577 }
 578
 579 const struct bpf_verifier_ops tracepoint_prog_ops = {
 580         .get_func_proto  = tp_prog_func_proto,
 581         .is_valid_access = tp_prog_is_valid_access,
 582 };
 583
 584 static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type,
 585                                     struct bpf_insn_access_aux *info)
 586 {
 587         const int size_sp = FIELD_SIZEOF(struct bpf_perf_event_data,
 588                                          sample_period);
 589
 590         if (off < 0 || off >= sizeof(struct bpf_perf_event_data))
 591                 return false;
 592         if (type != BPF_READ)
 593                 return false;
 594         if (off % size != 0)
 595                 return false;
 596
 597         switch (off) {
 598         case bpf_ctx_range(struct bpf_perf_event_data, sample_period):
 599                 bpf_ctx_record_field_size(info, size_sp);
 600                 if (!bpf_ctx_narrow_access_ok(off, size, size_sp))
 601                         return false;
 602                 break;
 603         default:
 604                 if (size != sizeof(long))
 605                         return false;
 606         }
 607
 608         return true;
 609 }
 610
 611 static u32 pe_prog_convert_ctx_access(enum bpf_access_type type,
 612                                       const struct bpf_insn *si,
 613                                       struct bpf_insn *insn_buf,
 614                                       struct bpf_prog *prog, u32 *target_size)
 615 {
 616         struct bpf_insn *insn = insn_buf;
 617
 618         switch (si->off) {
 619         case offsetof(struct bpf_perf_event_data, sample_period):
 620                 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern,
 621                                                        data), si->dst_reg, si->src_reg,
 622                                       offsetof(struct bpf_perf_event_data_kern, data));
 623                 *insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg,
 624                                       bpf_target_off(struct perf_sample_data, period, 8,
 625                                                      target_size));
 626                 break;
 627         default:
 628                 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern,
 629                                                        regs), si->dst_reg, si->src_reg,
 630                                       offsetof(struct bpf_perf_event_data_kern, regs));
 631                 *insn++ = BPF_LDX_MEM(BPF_SIZEOF(long), si->dst_reg, si->dst_reg,
 632                                       si->off);
 633                 break;
 634         }
 635
 636         return insn - insn_buf;
 637 }
 638
 639 const struct bpf_verifier_ops perf_event_prog_ops = {
 640         .get_func_proto         = tp_prog_func_proto,
 641         .is_valid_access        = pe_prog_is_valid_access,
 642         .convert_ctx_access     = pe_prog_convert_ctx_access,
 643 };