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AJvYcCVSGlvHQIAsASwpKEz8LQHgIPvkuX+va++L2UU50FKnlYouT5fgLisOURJyTvzzd91RXoEmtMvMZTmTx5t6XE2U@vger.kernel.org X-Gm-Message-State: AOJu0YzTyBKds7RaE4+MbfWjZ9VFwh1NQ1UHQ4JWgse/ltO9AgvTJl5/ Zfp2jFS3nLtFmJ5GqV5zeK6JkzHAZALtlHipL4jJsiCTRFYTrvFHq27b0iNSiuPnbHUs68yvmfe WW313HBg2SA== X-Google-Smtp-Source: AGHT+IEvvky+/EgLWwl3K8Zs/55gu/czFI/PdGTNrcAlGJ4vN8lSEIzR8QJ/i33rJKHm2HVt07K26itw31Jq X-Received: from pgdf9.prod.google.com ([2002:a05:6a02:5149:b0:b52:19fd:897f]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:244c:b0:27e:ec72:f67 with SMTP id d9443c01a7336-27eec7211f2mr148076835ad.6.1759172947312; Mon, 29 Sep 2025 12:09:07 -0700 (PDT) Date: Mon, 29 Sep 2025 12:08:00 -0700 In-Reply-To: <20250929190805.201446-1-irogers@google.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250929190805.201446-1-irogers@google.com> X-Mailer: git-send-email 2.51.0.570.gb178f27e6d-goog Message-ID: <20250929190805.201446-11-irogers@google.com> Subject: [PATCH v6 10/15] perf dso: Support BPF programs in dso__read_symbol From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , Charlie Jenkins , Eric Biggers , "Masami Hiramatsu (Google)" , James Clark , Collin Funk , "Dr. David Alan Gilbert" , Li Huafei , Athira Rajeev , Stephen Brennan , Dmitry Vyukov , Alexandre Ghiti , Haibo Xu , Andi Kleen , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, bpf@vger.kernel.org, llvm@lists.linux.dev, Song Liu Content-Type: text/plain; charset="UTF-8" Set the buffer to the code in the BPF linear info. This enables BPF JIT code disassembly by LLVM and capstone. Move the common but minimal disassmble_bpf_image call to disassemble_objdump so that it is only called after falling back to the objdump option. Similarly move the disassmble_bpf function to disassemble_objdump and rename to disassmble_bpf_libbfd to make it clearer that this support relies on libbfd. Signed-off-by: Ian Rogers --- tools/perf/util/disasm.c | 12 +++-- tools/perf/util/dso.c | 100 ++++++++++++++++++++++++++------------- tools/perf/util/libbfd.c | 4 +- tools/perf/util/libbfd.h | 6 +-- 4 files changed, 80 insertions(+), 42 deletions(-) diff --git a/tools/perf/util/disasm.c b/tools/perf/util/disasm.c index a1240543c89c..e64902e520ab 100644 --- a/tools/perf/util/disasm.c +++ b/tools/perf/util/disasm.c @@ -1521,6 +1521,12 @@ static int symbol__disassemble_objdump(const char *filename, struct symbol *sym, struct child_process objdump_process; int err; + if (dso__binary_type(dso) == DSO_BINARY_TYPE__BPF_PROG_INFO) + return symbol__disassemble_bpf_libbfd(sym, args); + + if (dso__binary_type(dso) == DSO_BINARY_TYPE__BPF_IMAGE) + return symbol__disassemble_bpf_image(sym, args); + err = asprintf(&command, "%s %s%s --start-address=0x%016" PRIx64 " --stop-address=0x%016" PRIx64 @@ -1655,11 +1661,7 @@ int symbol__disassemble(struct symbol *sym, struct annotate_args *args) pr_debug("annotating [%p] %30s : [%p] %30s\n", dso, dso__long_name(dso), sym, sym->name); - if (dso__binary_type(dso) == DSO_BINARY_TYPE__BPF_PROG_INFO) { - return symbol__disassemble_bpf(sym, args); - } else if (dso__binary_type(dso) == DSO_BINARY_TYPE__BPF_IMAGE) { - return symbol__disassemble_bpf_image(sym, args); - } else if (dso__binary_type(dso) == DSO_BINARY_TYPE__NOT_FOUND) { + if (dso__binary_type(dso) == DSO_BINARY_TYPE__NOT_FOUND) { return SYMBOL_ANNOTATE_ERRNO__COULDNT_DETERMINE_FILE_TYPE; } else if (dso__is_kcore(dso)) { kce.addr = map__rip_2objdump(map, sym->start); diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c index 87d075942de6..0aed5c8691bd 100644 --- a/tools/perf/util/dso.c +++ b/tools/perf/util/dso.c @@ -1816,23 +1816,17 @@ static int find_file_offset(u64 start, u64 len, u64 pgoff, void *arg) return 0; } -const u8 *dso__read_symbol(struct dso *dso, const char *symfs_filename, - const struct map *map, const struct symbol *sym, - u8 **out_buf, u64 *out_buf_len, bool *is_64bit) +static const u8 *__dso__read_symbol(struct dso *dso, const char *symfs_filename, + u64 start, size_t len, + u8 **out_buf, u64 *out_buf_len, bool *is_64bit) { struct nscookie nsc; - u64 start = map__rip_2objdump(map, sym->start); - u64 end = map__rip_2objdump(map, sym->end); - int fd, count; - u8 *buf = NULL; - size_t len; + int fd; + ssize_t count; struct find_file_offset_data data = { .ip = start, }; - - *out_buf = NULL; - *out_buf_len = 0; - *is_64bit = false; + u8 *code_buf = NULL; nsinfo__mountns_enter(dso__nsinfo(dso), &nsc); fd = open(symfs_filename, O_RDONLY); @@ -1840,28 +1834,70 @@ const u8 *dso__read_symbol(struct dso *dso, const char *symfs_filename, if (fd < 0) return NULL; - if (file__read_maps(fd, /*exe=*/true, find_file_offset, &data, is_64bit) == 0) - goto err; - - len = end - start; - buf = malloc(len); - if (buf == NULL) - goto err; - - count = pread(fd, buf, len, data.offset); + if (file__read_maps(fd, /*exe=*/true, find_file_offset, &data, is_64bit) == 0) { + close(fd); + return NULL; + } + code_buf = malloc(len); + if (code_buf == NULL) { + close(fd); + return NULL; + } + count = pread(fd, code_buf, len, data.offset); close(fd); - fd = -1; + if ((u64)count != len) { + free(code_buf); + return NULL; + } + *out_buf = code_buf; + *out_buf_len = len; + return code_buf; +} - if ((u64)count != len) - goto err; +/* + * Read a symbol into memory for disassembly by a library like capstone of + * libLLVM. If memory is allocated out_buf holds it. + */ +const u8 *dso__read_symbol(struct dso *dso, const char *symfs_filename, + const struct map *map, const struct symbol *sym, + u8 **out_buf, u64 *out_buf_len, bool *is_64bit) +{ + u64 start = map__rip_2objdump(map, sym->start); + u64 end = map__rip_2objdump(map, sym->end); + size_t len = end - start; - *out_buf = buf; - *out_buf_len = len; - return buf; + *out_buf = NULL; + *out_buf_len = 0; + *is_64bit = false; -err: - if (fd >= 0) - close(fd); - free(buf); - return NULL; + if (dso__binary_type(dso) == DSO_BINARY_TYPE__BPF_IMAGE) { + /* + * Note, there is fallback BPF image disassembly in the objdump + * version but it currently does nothing. + */ + return NULL; + } + if (dso__binary_type(dso) == DSO_BINARY_TYPE__BPF_PROG_INFO) { +#ifdef HAVE_LIBBPF_SUPPORT + struct bpf_prog_info_node *info_node; + struct perf_bpil *info_linear; + + *is_64bit = sizeof(void *) == sizeof(u64); + info_node = perf_env__find_bpf_prog_info(dso__bpf_prog(dso)->env, + dso__bpf_prog(dso)->id); + if (!info_node) { + errno = SYMBOL_ANNOTATE_ERRNO__BPF_MISSING_BTF; + return NULL; + } + info_linear = info_node->info_linear; + assert(len <= info_linear->info.jited_prog_len); + *out_buf_len = len; + return (const u8 *)(uintptr_t)(info_linear->info.jited_prog_insns); +#else + pr_debug("No BPF program disassembly support\n"); + return NULL; +#endif + } + return __dso__read_symbol(dso, symfs_filename, start, len, + out_buf, out_buf_len, is_64bit); } diff --git a/tools/perf/util/libbfd.c b/tools/perf/util/libbfd.c index 09a0eeb78a1a..01147fbf73b3 100644 --- a/tools/perf/util/libbfd.c +++ b/tools/perf/util/libbfd.c @@ -448,8 +448,8 @@ int libbfd_filename__read_debuglink(const char *filename, char *debuglink, return err; } -int symbol__disassemble_bpf(struct symbol *sym __maybe_unused, - struct annotate_args *args __maybe_unused) +int symbol__disassemble_bpf_libbfd(struct symbol *sym __maybe_unused, + struct annotate_args *args __maybe_unused) { #ifdef HAVE_LIBBPF_SUPPORT struct annotation *notes = symbol__annotation(sym); diff --git a/tools/perf/util/libbfd.h b/tools/perf/util/libbfd.h index 7441e95f8ec0..e300f171d1bd 100644 --- a/tools/perf/util/libbfd.h +++ b/tools/perf/util/libbfd.h @@ -29,7 +29,7 @@ int libbfd__read_build_id(const char *filename, struct build_id *bid, bool block int libbfd_filename__read_debuglink(const char *filename, char *debuglink, size_t size); -int symbol__disassemble_bpf(struct symbol *sym, struct annotate_args *args); +int symbol__disassemble_bpf_libbfd(struct symbol *sym, struct annotate_args *args); #else // !defined(HAVE_LIBBFD_SUPPORT) #include "annotate.h" @@ -72,8 +72,8 @@ static inline int libbfd_filename__read_debuglink(const char *filename __always_ return -1; } -static inline int symbol__disassemble_bpf(struct symbol *sym __always_unused, - struct annotate_args *args __always_unused) +static inline int symbol__disassemble_bpf_libbfd(struct symbol *sym __always_unused, + struct annotate_args *args __always_unused) { return SYMBOL_ANNOTATE_ERRNO__NO_LIBOPCODES_FOR_BPF; } -- 2.51.0.570.gb178f27e6d-goog