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AJvYcCUIWm6Z55rPqnT15LoxnhBLi+sGqb6ktjKhyhxwpODOI8sPv3ZL29gJ0DehEBWyrQreZZSccnY7N4KFS6BF5Nld@vger.kernel.org X-Gm-Message-State: AOJu0YyJlWtyEDrpoO8TWmKq5xRW4fn5yENifC4fJ3/gCIQM9O1kTXOq 48W68lRU9QCgC8FfZwmcWzohTACPIBoyEbeYf2YIgpewz4KKF2ITm3Nz/HEGihMF8+DK90XLKfk jURon/XhkNA== X-Google-Smtp-Source: AGHT+IFJk2oPW4r6McQs/nWZKohHl26TK542JQ9qyywVf6xez5/Uz4mzhA1OszwKINIzeSyPsG1Wz/ZjsSLx X-Received: from dlbvp8.prod.google.com ([2002:a05:7022:ff48:b0:11b:b1cd:e328]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7022:ea46:10b0:11b:9386:826d with SMTP id a92af1059eb24-11c9d8707d7mr4146724c88.42.1763865164339; Sat, 22 Nov 2025 18:32:44 -0800 (PST) Date: Sat, 22 Nov 2025 18:32:24 -0800 In-Reply-To: <20251123023225.8069-1-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: <20251123023225.8069-1-irogers@google.com> X-Mailer: git-send-email 2.52.0.rc2.455.g230fcf2819-goog Message-ID: <20251123023225.8069-9-irogers@google.com> Subject: [PATCH v1 8/9] perf symbol: Use fallbacks for sysfs__read_build_id From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , Suzuki K Poulose , Mike Leach , James Clark , John Garry , Will Deacon , Leo Yan , Athira Rajeev , tanze , Aditya Bodkhe , Stephen Brennan , Andi Kleen , Chun-Tse Shao , Thomas Falcon , Dapeng Mi , "Dr. David Alan Gilbert" , Christophe Leroy , "=?UTF-8?q?Krzysztof=20=C5=81opatowski?=" , "Masami Hiramatsu (Google)" , Alexandre Ghiti , Haibo Xu , Sergei Trofimovich , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Try libelf then symbol-minimal version in symbol.c. Reduce scope of NOTE_ALIGN macro. Signed-off-by: Ian Rogers --- tools/perf/util/perf-libelf.c | 56 ++++++++++++++++++++++++++++++++ tools/perf/util/perf-libelf.h | 12 ++++--- tools/perf/util/symbol-elf.c | 50 ---------------------------- tools/perf/util/symbol-minimal.c | 4 +-- tools/perf/util/symbol-minimal.h | 1 + tools/perf/util/symbol.c | 10 ++++++ 6 files changed, 76 insertions(+), 57 deletions(-) diff --git a/tools/perf/util/perf-libelf.c b/tools/perf/util/perf-libelf.c index a8a8c39056da..861cb7ae9b45 100644 --- a/tools/perf/util/perf-libelf.c +++ b/tools/perf/util/perf-libelf.c @@ -9,6 +9,11 @@ #include "build-id.h" #include "debug.h" +/* + * Align offset to 4 bytes as needed for note name and descriptor data. + */ +#define NOTE_ALIGN(n) (((n) + 3) & -4U) + Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep, GElf_Shdr *shp, const char *name, size_t *idx) { @@ -145,6 +150,57 @@ int libelf__read_build_id(int _fd, const char *filename, struct build_id *bid) return err; } +int libelf_sysfs__read_build_id(const char *filename, struct build_id *bid) +{ + size_t size = sizeof(bid->data); + int fd, err = -1; + + fd = open(filename, O_RDONLY); + if (fd < 0) + goto out; + + while (1) { + char bf[BUFSIZ]; + GElf_Nhdr nhdr; + size_t namesz, descsz; + + if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr)) + break; + + namesz = NOTE_ALIGN(nhdr.n_namesz); + descsz = NOTE_ALIGN(nhdr.n_descsz); + if (nhdr.n_type == NT_GNU_BUILD_ID && + nhdr.n_namesz == sizeof("GNU")) { + if (read(fd, bf, namesz) != (ssize_t)namesz) + break; + if (memcmp(bf, "GNU", sizeof("GNU")) == 0) { + size_t sz = min(descsz, size); + + if (read(fd, bid->data, sz) == (ssize_t)sz) { + memset(bid->data + sz, 0, size - sz); + bid->size = sz; + err = 0; + break; + } + } else if (read(fd, bf, descsz) != (ssize_t)descsz) + break; + } else { + int n = namesz + descsz; + + if (n > (int)sizeof(bf)) { + n = sizeof(bf); + pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n", + __func__, filename, nhdr.n_namesz, nhdr.n_descsz); + } + if (read(fd, bf, n) != n) + break; + } + } + close(fd); +out: + return err; +} + int libelf_filename__read_debuglink(const char *filename, char *debuglink, size_t size) { int fd, err = -1; diff --git a/tools/perf/util/perf-libelf.h b/tools/perf/util/perf-libelf.h index 167679f9fc9b..95fe8805aa41 100644 --- a/tools/perf/util/perf-libelf.h +++ b/tools/perf/util/perf-libelf.h @@ -21,17 +21,13 @@ struct build_id; # define PERF_ELF_C_READ_MMAP ELF_C_READ #endif -/* - * Align offset to 4 bytes as needed for note name and descriptor data. - */ -#define NOTE_ALIGN(n) (((n) + 3) & -4U) - Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep, GElf_Shdr *shp, const char *name, size_t *idx); int __libelf__read_build_id(Elf *elf, void *bf, size_t size); int libelf__read_build_id(int _fd, const char *filename, struct build_id *bid); +int libelf_sysfs__read_build_id(const char *filename, struct build_id *bid); int libelf_filename__read_debuglink(const char *filename, char *debuglink, size_t size); #else // !defined(HAVE_LIBELF_SUPPORT) @@ -43,6 +39,12 @@ static inline int libelf__read_build_id(int fd __always_unused, return -1; } +static inline int libelf_sysfs__read_build_id(const char *filename __always_unused, + struct build_id *bid __always_unused) +{ + return -1; +} + static inline int libelf_filename__read_debuglink(const char *filename __always_unused, char *debuglink __always_unused, size_t size __always_unused) diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c index d4a1b01010c1..5ddf8353e01b 100644 --- a/tools/perf/util/symbol-elf.c +++ b/tools/perf/util/symbol-elf.c @@ -751,56 +751,6 @@ int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss) return 0; } -int sysfs__read_build_id(const char *filename, struct build_id *bid) -{ - size_t size = sizeof(bid->data); - int fd, err = -1; - - fd = open(filename, O_RDONLY); - if (fd < 0) - goto out; - - while (1) { - char bf[BUFSIZ]; - GElf_Nhdr nhdr; - size_t namesz, descsz; - - if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr)) - break; - - namesz = NOTE_ALIGN(nhdr.n_namesz); - descsz = NOTE_ALIGN(nhdr.n_descsz); - if (nhdr.n_type == NT_GNU_BUILD_ID && - nhdr.n_namesz == sizeof("GNU")) { - if (read(fd, bf, namesz) != (ssize_t)namesz) - break; - if (memcmp(bf, "GNU", sizeof("GNU")) == 0) { - size_t sz = min(descsz, size); - if (read(fd, bid->data, sz) == (ssize_t)sz) { - memset(bid->data + sz, 0, size - sz); - bid->size = sz; - err = 0; - break; - } - } else if (read(fd, bf, descsz) != (ssize_t)descsz) - break; - } else { - int n = namesz + descsz; - - if (n > (int)sizeof(bf)) { - n = sizeof(bf); - pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n", - __func__, filename, nhdr.n_namesz, nhdr.n_descsz); - } - if (read(fd, bf, n) != n) - break; - } - } - close(fd); -out: - return err; -} - bool symsrc__possibly_runtime(struct symsrc *ss) { return ss->dynsym || ss->opdsec; diff --git a/tools/perf/util/symbol-minimal.c b/tools/perf/util/symbol-minimal.c index 8700c0628437..cc9055ba2f2a 100644 --- a/tools/perf/util/symbol-minimal.c +++ b/tools/perf/util/symbol-minimal.c @@ -194,8 +194,7 @@ int sym_min__read_build_id(int _fd, const char *filename, struct build_id *bid) return ret; } -#ifndef HAVE_LIBELF_SUPPORT -int sysfs__read_build_id(const char *filename, struct build_id *bid) +int sym_min_sysfs__read_build_id(const char *filename, struct build_id *bid) { int fd; int ret = -1; @@ -226,6 +225,7 @@ int sysfs__read_build_id(const char *filename, struct build_id *bid) return ret; } +#ifndef HAVE_LIBELF_SUPPORT int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name, enum dso_binary_type type) { diff --git a/tools/perf/util/symbol-minimal.h b/tools/perf/util/symbol-minimal.h index 185d98968212..5cce1f1f0f16 100644 --- a/tools/perf/util/symbol-minimal.h +++ b/tools/perf/util/symbol-minimal.h @@ -5,5 +5,6 @@ struct build_id; int sym_min__read_build_id(int _fd, const char *filename, struct build_id *bid); +int sym_min_sysfs__read_build_id(const char *filename, struct build_id *bid); #endif /* __PERF_SYMBOL_MINIMAL_H */ diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index 1152d11a0366..81f4428f7bed 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -2049,6 +2049,16 @@ int filename__read_build_id(const char *filename, struct build_id *bid, bool blo return err; } +int sysfs__read_build_id(const char *filename, struct build_id *bid) +{ + int err = libelf_sysfs__read_build_id(filename, bid); + + if (err == 0) + return 0; + + return sym_min_sysfs__read_build_id(filename, bid); +} + int filename__read_debuglink(const char *filename, char *debuglink, size_t size) { int err = libbfd_filename__read_debuglink(filename, debuglink, size); -- 2.52.0.rc2.455.g230fcf2819-goog