From: Ian Rogers Date: Tue, 2 Jun 2026 15:25:00 +0000 (-0700) Subject: perf env, dso, thread: Add _endian variants for e_machine helpers X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=f7c6e4b99ded250b3fdeaa5be4ccaac9ae05f8d9;p=thirdparty%2Fkernel%2Flinux.git perf env, dso, thread: Add _endian variants for e_machine helpers Add perf_arch_is_big_endian(), dso__read_e_machine_endian(), dso__e_machine_endian(), and thread__e_machine_endian() to support bi-endianness and cross-architecture analysis without breaking the existing API. These helpers allow querying the absolute endianness of a DSO or thread, which is required for tools like Capstone that need to set the correct disassembly mode. Assisted-by: Gemini:gemini-3.1-pro-preview Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Cc: Alexander Gordeev Cc: Heiko Carstens Cc: Honglei Wang Cc: Jan Polensky Cc: Sumanth Korikkar Cc: Thomas Richter Cc: Vasily Gorbik Signed-off-by: Arnaldo Carvalho de Melo --- diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c index b791e1b6b2cf0..7dced896c64ea 100644 --- a/tools/perf/util/dso.c +++ b/tools/perf/util/dso.c @@ -1220,7 +1220,8 @@ static enum dso_swap_type dso_swap_type__from_elf_data(unsigned char eidata) } /* Reads e_machine from fd, optionally caching data in dso. */ -uint16_t dso__read_e_machine(struct dso *optional_dso, int fd, uint32_t *e_flags) +uint16_t dso__read_e_machine_endian(struct dso *optional_dso, int fd, uint32_t *e_flags, + bool *is_big_endian) { uint16_t e_machine = EM_NONE; unsigned char e_ident[EI_NIDENT]; @@ -1250,6 +1251,9 @@ uint16_t dso__read_e_machine(struct dso *optional_dso, int fd, uint32_t *e_flags if (swap_type == DSO_SWAP__UNSET) return EM_NONE; // Bad ELF data encoding. + if (is_big_endian) + *is_big_endian = (e_ident[EI_DATA] == ELFDATA2MSB); + /* Cache the need for swapping. */ if (optional_dso) { assert(dso__needs_swap(optional_dso) == DSO_SWAP__UNSET || @@ -1288,7 +1292,8 @@ uint16_t dso__read_e_machine(struct dso *optional_dso, int fd, uint32_t *e_flags return e_machine; } -uint16_t dso__e_machine(struct dso *dso, struct machine *machine, uint32_t *e_flags) +uint16_t dso__e_machine_endian(struct dso *dso, struct machine *machine, uint32_t *e_flags, + bool *is_big_endian) { uint16_t e_machine = EM_NONE; int fd; @@ -1308,9 +1313,11 @@ uint16_t dso__e_machine(struct dso *dso, struct machine *machine, uint32_t *e_fl case DSO_BINARY_TYPE__BPF_IMAGE: case DSO_BINARY_TYPE__OOL: case DSO_BINARY_TYPE__JAVA_JIT: - if (e_flags) - *e_flags = EF_HOST; - return EM_HOST; + if (is_big_endian) { + *is_big_endian = perf_arch_is_big_endian( + machine && machine->env ? perf_env__arch(machine->env) : NULL); + } + return perf_env__e_machine(machine ? machine->env : NULL, e_flags); case DSO_BINARY_TYPE__DEBUGLINK: case DSO_BINARY_TYPE__BUILD_ID_CACHE: case DSO_BINARY_TYPE__BUILD_ID_CACHE_DEBUGINFO: @@ -1338,7 +1345,7 @@ uint16_t dso__e_machine(struct dso *dso, struct machine *machine, uint32_t *e_fl try_to_open_dso(dso, machine); fd = dso__data(dso)->fd; if (fd >= 0) - e_machine = dso__read_e_machine(dso, fd, e_flags); + e_machine = dso__read_e_machine_endian(dso, fd, e_flags, is_big_endian); else if (e_flags) *e_flags = 0; diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h index ede691e9a2495..2916b954a804b 100644 --- a/tools/perf/util/dso.h +++ b/tools/perf/util/dso.h @@ -866,8 +866,18 @@ int dso__data_file_size(struct dso *dso, struct machine *machine); off_t dso__data_size(struct dso *dso, struct machine *machine); ssize_t dso__data_read_offset(struct dso *dso, struct machine *machine, u64 offset, u8 *data, ssize_t size); -uint16_t dso__read_e_machine(struct dso *optional_dso, int fd, uint32_t *e_flags); -uint16_t dso__e_machine(struct dso *dso, struct machine *machine, uint32_t *e_flags); +uint16_t dso__read_e_machine_endian(struct dso *optional_dso, int fd, uint32_t *e_flags, + bool *is_big_endian); +static inline uint16_t dso__read_e_machine(struct dso *optional_dso, int fd, uint32_t *e_flags) +{ + return dso__read_e_machine_endian(optional_dso, fd, e_flags, NULL); +} +uint16_t dso__e_machine_endian(struct dso *dso, struct machine *machine, uint32_t *e_flags, + bool *is_big_endian); +static inline uint16_t dso__e_machine(struct dso *dso, struct machine *machine, uint32_t *e_flags) +{ + return dso__e_machine_endian(dso, machine, e_flags, NULL); +} ssize_t dso__data_read_addr(struct dso *dso, struct map *map, struct machine *machine, u64 addr, u8 *data, ssize_t size); diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c index 0cd23b5fc6515..fae70b07ba8de 100644 --- a/tools/perf/util/env.c +++ b/tools/perf/util/env.c @@ -342,6 +342,22 @@ int perf_env__kernel_is_64_bit(struct perf_env *env) return env->kernel_is_64_bit; } +bool perf_arch_is_big_endian(const char *arch) +{ + if (!arch) + return __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__; + + if (str_ends_with(arch, "_be") || !strcmp(arch, "sparc") || !strcmp(arch, "sparc64") || + !strcmp(arch, "s390") || !strcmp(arch, "s390x") || !strcmp(arch, "powerpc") || + !strcmp(arch, "ppc") || !strcmp(arch, "ppc64") || + !strcmp(arch, "mips") || !strcmp(arch, "mips64") || !strcmp(arch, "parisc") || + !strcmp(arch, "parisc64") || !strcmp(arch, "m68k") || + !strcmp(arch, "armeb") || !strcmp(arch, "mipseb") || !strcmp(arch, "mips64eb")) + return true; + + return false; +} + int perf_env__set_cmdline(struct perf_env *env, int argc, const char *argv[]) { int i; diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h index bde192fd5be59..dd9907dbc3450 100644 --- a/tools/perf/util/env.h +++ b/tools/perf/util/env.h @@ -175,6 +175,7 @@ void free_cpu_domain_info(struct cpu_domain_map **cd_map, u32 schedstat_version, void perf_env__exit(struct perf_env *env); int perf_env__kernel_is_64_bit(struct perf_env *env); +bool perf_arch_is_big_endian(const char *arch); int perf_env__set_cmdline(struct perf_env *env, int argc, const char *argv[]); diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c index aac9cb75dcf44..ba33c0dfc18fe 100644 --- a/tools/perf/util/thread.c +++ b/tools/perf/util/thread.c @@ -56,6 +56,7 @@ struct thread *thread__new(pid_t pid, pid_t tid) thread__set_cpu(thread, -1); thread__set_guest_cpu(thread, -1); thread__set_e_machine(thread, EM_NONE); + thread__set_e_is_big_endian(thread, false); thread__set_lbr_stitch_enable(thread, false); INIT_LIST_HEAD(thread__namespaces_list(thread)); INIT_LIST_HEAD(thread__comm_list(thread)); @@ -429,7 +430,7 @@ void thread__find_cpumode_addr_location(struct thread *thread, u64 addr, } } -static uint16_t read_proc_e_machine_for_pid(pid_t pid, uint32_t *e_flags) +static uint16_t read_proc_e_machine_for_pid(pid_t pid, uint32_t *e_flags, bool *is_big_endian) { char path[6 /* "/proc/" */ + 11 /* max length of pid */ + 5 /* "/exe\0" */]; int fd; @@ -438,7 +439,8 @@ static uint16_t read_proc_e_machine_for_pid(pid_t pid, uint32_t *e_flags) snprintf(path, sizeof(path), "/proc/%d/exe", pid); fd = open(path, O_RDONLY); if (fd >= 0) { - e_machine = dso__read_e_machine(/*optional_dso=*/NULL, fd, e_flags); + e_machine = dso__read_e_machine_endian(/*optional_dso=*/NULL, fd, e_flags, + is_big_endian); close(fd); } return e_machine; @@ -448,6 +450,7 @@ struct thread__e_machine_callback_args { struct machine *machine; uint32_t e_flags; uint16_t e_machine; + bool is_big_endian; }; static int thread__e_machine_callback(struct map *map, void *_args) @@ -458,24 +461,38 @@ static int thread__e_machine_callback(struct map *map, void *_args) if (!dso) return 0; // No dso, continue search. - args->e_machine = dso__e_machine(dso, args->machine, &args->e_flags); + args->e_machine = + dso__e_machine_endian(dso, args->machine, &args->e_flags, &args->is_big_endian); return args->e_machine != EM_NONE ? 1 /* stop search */ : 0 /* continue search */; } -uint16_t thread__e_machine(struct thread *thread, struct machine *machine, uint32_t *e_flags) +uint16_t thread__e_machine_endian(struct thread *thread, struct machine *machine, uint32_t *e_flags, + bool *is_big_endian) { pid_t tid, pid; - uint16_t e_machine = RC_CHK_ACCESS(thread)->e_machine; + uint16_t e_machine; uint32_t local_e_flags = 0; - struct thread__e_machine_callback_args args = { - .machine = machine, - .e_flags = 0, - .e_machine = EM_NONE, - }; + struct thread__e_machine_callback_args args; + + if (!thread) { + if (is_big_endian) { + *is_big_endian = perf_arch_is_big_endian( + machine && machine->env ? perf_env__arch(machine->env) : NULL); + } + return perf_env__e_machine(machine ? machine->env : NULL, e_flags); + } + + e_machine = RC_CHK_ACCESS(thread)->e_machine; + args.machine = machine; + args.e_flags = 0; + args.e_machine = EM_NONE; + args.is_big_endian = false; if (e_machine != EM_NONE) { if (e_flags) *e_flags = thread__e_flags(thread); + if (is_big_endian) + *is_big_endian = thread__e_is_big_endian(thread); return e_machine; } @@ -483,6 +500,7 @@ uint16_t thread__e_machine(struct thread *thread, struct machine *machine, uint3 struct maps *maps = thread__maps(thread); machine = maps__machine(maps); + args.machine = machine; } tid = thread__tid(thread); pid = thread__pid(thread); @@ -490,7 +508,8 @@ uint16_t thread__e_machine(struct thread *thread, struct machine *machine, uint3 struct thread *parent = machine__findnew_thread(machine, pid, pid); if (parent) { - e_machine = thread__e_machine(parent, machine, &local_e_flags); + e_machine = thread__e_machine_endian(parent, machine, &local_e_flags, + &args.is_big_endian); thread__put(parent); goto out; } @@ -515,16 +534,27 @@ uint16_t thread__e_machine(struct thread *thread, struct machine *machine, uint3 is_live = !!session->data; } /* Read from /proc/pid/exe if live. */ - if (is_live) - e_machine = read_proc_e_machine_for_pid(pid, &local_e_flags); + if (is_live) { + e_machine = read_proc_e_machine_for_pid(pid, &local_e_flags, + &args.is_big_endian); + } else if (machine && machine->env) { + /* Offline analysis: fallback to environment metadata. */ + e_machine = perf_env__e_machine(machine->env, &local_e_flags); + args.is_big_endian = perf_arch_is_big_endian(perf_env__arch(machine->env)); + } } out: if (e_machine != EM_NONE) { - thread__set_e_machine(thread, e_machine); thread__set_e_flags(thread, local_e_flags); + thread__set_e_is_big_endian(thread, args.is_big_endian); + thread__set_e_machine(thread, e_machine); + if (is_big_endian) + *is_big_endian = args.is_big_endian; } else { e_machine = EM_HOST; local_e_flags = EF_HOST; + if (is_big_endian) + *is_big_endian = (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__); } if (e_flags) *e_flags = local_e_flags; diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h index f5792d3e8a16f..d82fce8173aef 100644 --- a/tools/perf/util/thread.h +++ b/tools/perf/util/thread.h @@ -69,6 +69,11 @@ DECLARE_RC_STRUCT(thread) { * computed. */ uint16_t e_machine; + /** + * @e_is_big_endian: True if the ELF architecture of the thread is big endian. + * Valid if e_machine != EM_NONE. + */ + bool e_is_big_endian; /* LBR call stack stitch */ bool lbr_stitch_enable; struct lbr_stitch *lbr_stitch; @@ -311,7 +316,13 @@ static inline void thread__set_filter_entry_depth(struct thread *thread, int dep RC_CHK_ACCESS(thread)->filter_entry_depth = depth; } -uint16_t thread__e_machine(struct thread *thread, struct machine *machine, uint32_t *e_flags); +uint16_t thread__e_machine_endian(struct thread *thread, struct machine *machine, uint32_t *e_flags, + bool *is_big_endian); +static inline uint16_t thread__e_machine(struct thread *thread, struct machine *machine, + uint32_t *e_flags) +{ + return thread__e_machine_endian(thread, machine, e_flags, NULL); +} static inline void thread__set_e_machine(struct thread *thread, uint16_t e_machine) { @@ -328,6 +339,16 @@ static inline void thread__set_e_flags(struct thread *thread, uint32_t e_flags) RC_CHK_ACCESS(thread)->e_flags = e_flags; } +static inline bool thread__e_is_big_endian(const struct thread *thread) +{ + return RC_CHK_ACCESS(thread)->e_is_big_endian; +} + +static inline void thread__set_e_is_big_endian(struct thread *thread, bool is_big_endian) +{ + RC_CHK_ACCESS(thread)->e_is_big_endian = is_big_endian; +} + static inline bool thread__lbr_stitch_enable(const struct thread *thread) {