diff options
Diffstat (limited to 'tools/perf/util/thread.c')
| -rw-r--r-- | tools/perf/util/thread.c | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c index 0ffdd52d86d7..89585f53c1d5 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 +427,82 @@ 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; +} + +static int thread__e_machine_callback(struct map *map, void *machine) +{ + struct dso *dso = map__dso(map); + + _Static_assert(0 == EM_NONE, "Unexpected EM_NONE"); + if (!dso) + return EM_NONE; + + return dso__e_machine(dso, 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. */ + } + /* Reading on the PID thread. First try to find from the maps. */ + e_machine = maps__for_each_map(thread__maps(thread), + thread__e_machine_callback, + machine); + if (e_machine == EM_NONE) { + /* Maps failed, perhaps we're live with map events disabled. */ + bool is_live = machine->machines == NULL; + + if (!is_live) { + /* Check if the session has a data file. */ + struct perf_session *session = container_of(machine->machines, + struct perf_session, + machines); + + is_live = !!session->data; + } + /* Read from /proc/pid/exe if live. */ + if (is_live) + 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)) |