On Mon, Feb 10, 2025 at 08:51:05AM -0800, Ian Rogers wrote: > Use the executable from /proc/pid/exe and read the e_machine from the > ELF header. On failure use EM_HOST. Change builtin-trace syscall > functions to pass e_machine from the thread rather than EM_HOST, so > that in later patches when syscalltbl can use the e_machine the system > calls are specific to the architecture.
Reviewed-by: Charlie Jenkins <[email protected]> Tested-by: Charlie Jenkins <[email protected]> > > Signed-off-by: Ian Rogers <[email protected]> > Reviewed-by: Howard Chu <[email protected]> > --- > tools/perf/builtin-trace.c | 41 ++++++++++++++++--------------- > tools/perf/util/thread.c | 50 ++++++++++++++++++++++++++++++++++++++ > tools/perf/util/thread.h | 14 ++++++++++- > 3 files changed, 85 insertions(+), 20 deletions(-) > > diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c > index 4b77c2ab3dba..1ae609555018 100644 > --- a/tools/perf/builtin-trace.c > +++ b/tools/perf/builtin-trace.c > @@ -2678,16 +2678,17 @@ static int trace__sys_enter(struct trace *trace, > struct evsel *evsel, > int printed = 0; > struct thread *thread; > int id = perf_evsel__sc_tp_uint(evsel, id, sample), err = -1; > - int augmented_args_size = 0; > + int augmented_args_size = 0, e_machine; > void *augmented_args = NULL; > /* TODO: get e_machine from thread. */ > - struct syscall *sc = trace__syscall_info(trace, evsel, EM_HOST, id); > + struct syscall *sc; > struct thread_trace *ttrace; > > - if (sc == NULL) > - return -1; > - > thread = machine__findnew_thread(trace->host, sample->pid, sample->tid); > + e_machine = thread__e_machine(thread, trace->host); > + sc = trace__syscall_info(trace, evsel, e_machine, id); > + if (sc == NULL) > + goto out_put; > ttrace = thread__trace(thread, trace->output); > if (ttrace == NULL) > goto out_put; > @@ -2756,16 +2757,18 @@ static int trace__fprintf_sys_enter(struct trace > *trace, struct evsel *evsel, > struct thread *thread; > int id = perf_evsel__sc_tp_uint(evsel, id, sample), err = -1; > /* TODO: get e_machine from thread. */ > - struct syscall *sc = trace__syscall_info(trace, evsel, EM_HOST, id); > + struct syscall *sc; > char msg[1024]; > void *args, *augmented_args = NULL; > - int augmented_args_size; > + int augmented_args_size, e_machine; > size_t printed = 0; > > - if (sc == NULL) > - return -1; > > thread = machine__findnew_thread(trace->host, sample->pid, sample->tid); > + e_machine = thread__e_machine(thread, trace->host); > + sc = trace__syscall_info(trace, evsel, e_machine, id); > + if (sc == NULL) > + return -1; > ttrace = thread__trace(thread, trace->output); > /* > * We need to get ttrace just to make sure it is there when > syscall__scnprintf_args() > @@ -2830,15 +2833,15 @@ static int trace__sys_exit(struct trace *trace, > struct evsel *evsel, > bool duration_calculated = false; > struct thread *thread; > int id = perf_evsel__sc_tp_uint(evsel, id, sample), err = -1, > callchain_ret = 0, printed = 0; > - int alignment = trace->args_alignment; > - /* TODO: get e_machine from thread. */ > - struct syscall *sc = trace__syscall_info(trace, evsel, EM_HOST, id); > + int alignment = trace->args_alignment, e_machine; > + struct syscall *sc; > struct thread_trace *ttrace; > > - if (sc == NULL) > - return -1; > - > thread = machine__findnew_thread(trace->host, sample->pid, sample->tid); > + e_machine = thread__e_machine(thread, trace->host); > + sc = trace__syscall_info(trace, evsel, e_machine, id); > + if (sc == NULL) > + goto out_put; > ttrace = thread__trace(thread, trace->output); > if (ttrace == NULL) > goto out_put; > @@ -3185,8 +3188,8 @@ static int trace__event_handler(struct trace *trace, > struct evsel *evsel, > > if (evsel == trace->syscalls.events.bpf_output) { > int id = perf_evsel__sc_tp_uint(evsel, id, sample); > - /* TODO: get e_machine from thread. */ > - struct syscall *sc = trace__syscall_info(trace, evsel, EM_HOST, > id); > + int e_machine = thread ? thread__e_machine(thread, trace->host) > : EM_HOST; > + struct syscall *sc = trace__syscall_info(trace, evsel, > e_machine, id); > > if (sc) { > fprintf(trace->output, "%s(", sc->name); > @@ -4764,6 +4767,7 @@ static size_t trace__fprintf_thread(FILE *fp, struct > thread *thread, struct trac > { > size_t printed = 0; > struct thread_trace *ttrace = thread__priv(thread); > + int e_machine = thread__e_machine(thread, trace->host); > double ratio; > > if (ttrace == NULL) > @@ -4783,8 +4787,7 @@ static size_t trace__fprintf_thread(FILE *fp, struct > thread *thread, struct trac > else if (fputc('\n', fp) != EOF) > ++printed; > > - /* TODO: get e_machine from thread. */ > - printed += thread__dump_stats(ttrace, trace, EM_HOST, fp); > + printed += thread__dump_stats(ttrace, trace, e_machine, fp); > > return printed; > } > diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c > index 0ffdd52d86d7..a07446a280ed 100644 > --- a/tools/perf/util/thread.c > +++ b/tools/perf/util/thread.c > @@ -1,5 +1,7 @@ > // SPDX-License-Identifier: GPL-2.0 > +#include <elf.h> > #include <errno.h> > +#include <fcntl.h> > #include <stdlib.h> > #include <stdio.h> > #include <string.h> > @@ -16,6 +18,7 @@ > #include "symbol.h" > #include "unwind.h" > #include "callchain.h" > +#include "dwarf-regs.h" > > #include <api/fs/fs.h> > > @@ -51,6 +54,7 @@ struct thread *thread__new(pid_t pid, pid_t tid) > thread__set_ppid(thread, -1); > thread__set_cpu(thread, -1); > thread__set_guest_cpu(thread, -1); > + thread__set_e_machine(thread, EM_NONE); > thread__set_lbr_stitch_enable(thread, false); > INIT_LIST_HEAD(thread__namespaces_list(thread)); > INIT_LIST_HEAD(thread__comm_list(thread)); > @@ -423,6 +427,52 @@ void thread__find_cpumode_addr_location(struct thread > *thread, u64 addr, > } > } > > +static uint16_t read_proc_e_machine_for_pid(pid_t pid) > +{ > + char path[6 /* "/proc/" */ + 11 /* max length of pid */ + 5 /* "/exe\0" > */]; > + int fd; > + uint16_t e_machine = EM_NONE; > + > + snprintf(path, sizeof(path), "/proc/%d/exe", pid); > + fd = open(path, O_RDONLY); > + if (fd >= 0) { > + _Static_assert(offsetof(Elf32_Ehdr, e_machine) == 18, > "Unexpected offset"); > + _Static_assert(offsetof(Elf64_Ehdr, e_machine) == 18, > "Unexpected offset"); > + if (pread(fd, &e_machine, sizeof(e_machine), 18) != > sizeof(e_machine)) > + e_machine = EM_NONE; > + close(fd); > + } > + return e_machine; > +} > + > +uint16_t thread__e_machine(struct thread *thread, struct machine *machine) > +{ > + pid_t tid, pid; > + uint16_t e_machine = RC_CHK_ACCESS(thread)->e_machine; > + > + if (e_machine != EM_NONE) > + return e_machine; > + > + tid = thread__tid(thread); > + pid = thread__pid(thread); > + if (pid != tid) { > + struct thread *parent = machine__findnew_thread(machine, pid, > pid); > + > + if (parent) { > + e_machine = thread__e_machine(parent, machine); > + thread__set_e_machine(thread, e_machine); > + return e_machine; > + } > + /* Something went wrong, fallback. */ > + } > + e_machine = read_proc_e_machine_for_pid(pid); > + if (e_machine != EM_NONE) > + thread__set_e_machine(thread, e_machine); > + else > + e_machine = EM_HOST; > + return e_machine; > +} > + > struct thread *thread__main_thread(struct machine *machine, struct thread > *thread) > { > if (thread__pid(thread) == thread__tid(thread)) > diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h > index 6cbf6eb2812e..cd574a896418 100644 > --- a/tools/perf/util/thread.h > +++ b/tools/perf/util/thread.h > @@ -60,7 +60,11 @@ DECLARE_RC_STRUCT(thread) { > struct srccode_state srccode_state; > bool filter; > int filter_entry_depth; > - > + /** > + * @e_machine: The ELF EM_* associated with the thread. EM_NONE if not > + * computed. > + */ > + uint16_t e_machine; > /* LBR call stack stitch */ > bool lbr_stitch_enable; > struct lbr_stitch *lbr_stitch; > @@ -302,6 +306,14 @@ 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); > + > +static inline void thread__set_e_machine(struct thread *thread, uint16_t > e_machine) > +{ > + RC_CHK_ACCESS(thread)->e_machine = e_machine; > +} > + > + > static inline bool thread__lbr_stitch_enable(const struct thread *thread) > { > return RC_CHK_ACCESS(thread)->lbr_stitch_enable; > -- > 2.48.1.502.g6dc24dfdaf-goog >
