tools/perf/util/disasm_bpf.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2
   3 #include "util/annotate.h"
   4 #include "util/disasm_bpf.h"
   5 #include "util/symbol.h"
   6 #include <linux/zalloc.h>
   7 #include <string.h>
   8
   9 #if defined(HAVE_LIBBFD_SUPPORT) && defined(HAVE_LIBBPF_SUPPORT)
  10 #define PACKAGE "perf"
  11 #include <bfd.h>
  12 #include <bpf/bpf.h>
  13 #include <bpf/btf.h>
  14 #include <bpf/libbpf.h>
  15 #include <dis-asm.h>
  16 #include <errno.h>
  17 #include <linux/btf.h>
  18 #include <tools/dis-asm-compat.h>
  19
  20 #include "util/bpf-event.h"
  21 #include "util/bpf-utils.h"
  22 #include "util/debug.h"
  23 #include "util/dso.h"
  24 #include "util/map.h"
  25 #include "util/env.h"
  26 #include "util/util.h"
  27
  28 int symbol__disassemble_bpf(struct symbol *sym, struct annotate_args *args)
  29 {
  30         struct annotation *notes = symbol__annotation(sym);
  31         struct bpf_prog_linfo *prog_linfo = NULL;
  32         struct bpf_prog_info_node *info_node;
  33         int len = sym->end - sym->start;
  34         disassembler_ftype disassemble;
  35         struct map *map = args->ms.map;
  36         struct perf_bpil *info_linear;
  37         struct disassemble_info info;
  38         struct dso *dso = map__dso(map);
  39         int pc = 0, count, sub_id;
  40         struct btf *btf = NULL;
  41         char tpath[PATH_MAX];
  42         size_t buf_size;
  43         int nr_skip = 0;
  44         char *buf;
  45         bfd *bfdf;
  46         int ret;
  47         FILE *s;
  48
  49         if (dso__binary_type(dso) != DSO_BINARY_TYPE__BPF_PROG_INFO)
  50                 return SYMBOL_ANNOTATE_ERRNO__BPF_INVALID_FILE;
  51
  52         pr_debug("%s: handling sym %s addr %" PRIx64 " len %" PRIx64 "\n", __func__,
  53                   sym->name, sym->start, sym->end - sym->start);
  54
  55         memset(tpath, 0, sizeof(tpath));
  56         perf_exe(tpath, sizeof(tpath));
  57
  58         bfdf = bfd_openr(tpath, NULL);
  59         if (bfdf == NULL)
  60                 abort();
  61
  62         if (!bfd_check_format(bfdf, bfd_object))
  63                 abort();
  64
  65         s = open_memstream(&buf, &buf_size);
  66         if (!s) {
  67                 ret = errno;
  68                 goto out;
  69         }
  70         init_disassemble_info_compat(&info, s,
  71                                      (fprintf_ftype) fprintf,
  72                                      fprintf_styled);
  73         info.arch = bfd_get_arch(bfdf);
  74         info.mach = bfd_get_mach(bfdf);
  75
  76         info_node = perf_env__find_bpf_prog_info(dso__bpf_prog(dso)->env,
  77                                                  dso__bpf_prog(dso)->id);
  78         if (!info_node) {
  79                 ret = SYMBOL_ANNOTATE_ERRNO__BPF_MISSING_BTF;
  80                 goto out;
  81         }
  82         info_linear = info_node->info_linear;
  83         sub_id = dso__bpf_prog(dso)->sub_id;
  84
  85         info.buffer = (void *)(uintptr_t)(info_linear->info.jited_prog_insns);
  86         info.buffer_length = info_linear->info.jited_prog_len;
  87
  88         if (info_linear->info.nr_line_info)
  89                 prog_linfo = bpf_prog_linfo__new(&info_linear->info);
  90
  91         if (info_linear->info.btf_id) {
  92                 struct btf_node *node;
  93
  94                 node = perf_env__find_btf(dso__bpf_prog(dso)->env,
  95                                           info_linear->info.btf_id);
  96                 if (node)
  97                         btf = btf__new((__u8 *)(node->data),
  98                                        node->data_size);
  99         }
 100
 101         disassemble_init_for_target(&info);
 102
 103 #ifdef DISASM_FOUR_ARGS_SIGNATURE
 104         disassemble = disassembler(info.arch,
 105                                    bfd_big_endian(bfdf),
 106                                    info.mach,
 107                                    bfdf);
 108 #else
 109         disassemble = disassembler(bfdf);
 110 #endif
 111         if (disassemble == NULL)
 112                 abort();
 113
 114         fflush(s);
 115         do {
 116                 const struct bpf_line_info *linfo = NULL;
 117                 struct disasm_line *dl;
 118                 size_t prev_buf_size;
 119                 const char *srcline;
 120                 u64 addr;
 121
 122                 addr = pc + ((u64 *)(uintptr_t)(info_linear->info.jited_ksyms))[sub_id];
 123                 count = disassemble(pc, &info);
 124
 125                 if (prog_linfo)
 126                         linfo = bpf_prog_linfo__lfind_addr_func(prog_linfo,
 127                                                                 addr, sub_id,
 128                                                                 nr_skip);
 129
 130                 if (linfo && btf) {
 131                         srcline = btf__name_by_offset(btf, linfo->line_off);
 132                         nr_skip++;
 133                 } else
 134                         srcline = NULL;
 135
 136                 fprintf(s, "\n");
 137                 prev_buf_size = buf_size;
 138                 fflush(s);
 139
 140                 if (!annotate_opts.hide_src_code && srcline) {
 141                         args->offset = -1;
 142                         args->line = strdup(srcline);
 143                         args->line_nr = 0;
 144                         args->fileloc = NULL;
 145                         args->ms.sym  = sym;
 146                         dl = disasm_line__new(args);
 147                         if (dl) {
 148                                 annotation_line__add(&dl->al,
 149                                                      &notes->src->source);
 150                         }
 151                 }
 152
 153                 args->offset = pc;
 154                 args->line = buf + prev_buf_size;
 155                 args->line_nr = 0;
 156                 args->fileloc = NULL;
 157                 args->ms.sym  = sym;
 158                 dl = disasm_line__new(args);
 159                 if (dl)
 160                         annotation_line__add(&dl->al, &notes->src->source);
 161
 162                 pc += count;
 163         } while (count > 0 && pc < len);
 164
 165         ret = 0;
 166 out:
 167         free(prog_linfo);
 168         btf__free(btf);
 169         fclose(s);
 170         bfd_close(bfdf);
 171         return ret;
 172 }
 173 #else // defined(HAVE_LIBBFD_SUPPORT) && defined(HAVE_LIBBPF_SUPPORT)
 174 int symbol__disassemble_bpf(struct symbol *sym __maybe_unused, struct annotate_args *args __maybe_unused)
 175 {
 176         return SYMBOL_ANNOTATE_ERRNO__NO_LIBOPCODES_FOR_BPF;
 177 }
 178 #endif // defined(HAVE_LIBBFD_SUPPORT) && defined(HAVE_LIBBPF_SUPPORT)
 179
 180 int symbol__disassemble_bpf_image(struct symbol *sym, struct annotate_args *args)
 181 {
 182         struct annotation *notes = symbol__annotation(sym);
 183         struct disasm_line *dl;
 184
 185         args->offset = -1;
 186         args->line = strdup("to be implemented");
 187         args->line_nr = 0;
 188         args->fileloc = NULL;
 189         dl = disasm_line__new(args);
 190         if (dl)
 191                 annotation_line__add(&dl->al, &notes->src->source);
 192
 193         zfree(&args->line);
 194         return 0;
 195 }