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Message-ID: <20260123222209.1181249-3-irogers@google.com>
Date: Fri, 23 Jan 2026 14:22:07 -0800
From: Ian Rogers <irogers@...gle.com>
To: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>,
Ian Rogers <irogers@...gle.com>, Adrian Hunter <adrian.hunter@...el.com>,
James Clark <james.clark@...aro.org>, Guo Ren <guoren@...nel.org>,
Tianyou Li <tianyou.li@...el.com>, Athira Rajeev <atrajeev@...ux.ibm.com>,
Stephen Brennan <stephen.s.brennan@...cle.com>, Aditya Bodkhe <aditya.b1@...ux.ibm.com>,
Chun-Tse Shao <ctshao@...gle.com>, Swapnil Sapkal <swapnil.sapkal@....com>,
Howard Chu <howardchu95@...il.com>, Sergei Trofimovich <slyich@...il.com>,
Shimin Guo <shimin.guo@...dio.com>, linux-perf-users@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-csky@...r.kernel.org
Subject: [PATCH v1 2/4] perf thread: Add optional e_flags output argument to thread__e_machine
The e_flags are needed to accurately compute complete perf register
information for CSKY. Add the ability to read and have this value
associated with a thread. This change doesn't wire up the use of the
e_flags except in disasm where use already exists but just wasn't set
up yet.
Signed-off-by: Ian Rogers <irogers@...gle.com>
---
tools/perf/builtin-script.c | 14 +++--
tools/perf/builtin-trace.c | 12 ++--
tools/perf/util/annotate.c | 5 +-
tools/perf/util/disasm.c | 5 +-
tools/perf/util/disasm.h | 2 +-
tools/perf/util/dso.c | 43 +++++++++++---
tools/perf/util/dso.h | 4 +-
.../scripting-engines/trace-event-python.c | 2 +-
tools/perf/util/session.c | 4 +-
tools/perf/util/thread.c | 59 +++++++++++++------
tools/perf/util/thread.h | 16 ++++-
tools/perf/util/unwind-libdw.c | 4 +-
12 files changed, 122 insertions(+), 48 deletions(-)
diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 372bede30230..8c0de27a9713 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -2504,11 +2504,17 @@ static void process_event(struct perf_script *script,
symbol_conf.bt_stop_list, fp);
}
- if (PRINT_FIELD(IREGS))
- perf_sample__fprintf_iregs(sample, attr, thread__e_machine(thread, machine), fp);
+ if (PRINT_FIELD(IREGS)) {
+ perf_sample__fprintf_iregs(sample, attr,
+ thread__e_machine(thread, machine, /*e_flags=*/NULL),
+ fp);
+ }
- if (PRINT_FIELD(UREGS))
- perf_sample__fprintf_uregs(sample, attr, thread__e_machine(thread, machine), fp);
+ if (PRINT_FIELD(UREGS)) {
+ perf_sample__fprintf_uregs(sample, attr,
+ thread__e_machine(thread, machine, /*e_flags=*/NULL),
+ fp);
+ }
if (PRINT_FIELD(BRSTACK))
perf_sample__fprintf_brstack(sample, thread, evsel, fp);
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 8df5ca44e4f9..311d9da9896a 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -2789,7 +2789,7 @@ static int trace__sys_enter(struct trace *trace, struct evsel *evsel,
struct thread_trace *ttrace;
thread = machine__findnew_thread(trace->host, sample->pid, sample->tid);
- e_machine = thread__e_machine(thread, trace->host);
+ e_machine = thread__e_machine(thread, trace->host, /*e_flags=*/NULL);
sc = trace__syscall_info(trace, evsel, e_machine, id);
if (sc == NULL)
goto out_put;
@@ -2868,7 +2868,7 @@ static int trace__fprintf_sys_enter(struct trace *trace, struct evsel *evsel,
thread = machine__findnew_thread(trace->host, sample->pid, sample->tid);
- e_machine = thread__e_machine(thread, trace->host);
+ e_machine = thread__e_machine(thread, trace->host, /*e_flags=*/NULL);
sc = trace__syscall_info(trace, evsel, e_machine, id);
if (sc == NULL)
goto out_put;
@@ -2934,7 +2934,7 @@ static int trace__sys_exit(struct trace *trace, struct evsel *evsel,
struct thread_trace *ttrace;
thread = machine__findnew_thread(trace->host, sample->pid, sample->tid);
- e_machine = thread__e_machine(thread, trace->host);
+ e_machine = thread__e_machine(thread, trace->host, /*e_flags=*/NULL);
sc = trace__syscall_info(trace, evsel, e_machine, id);
if (sc == NULL)
goto out_put;
@@ -3285,7 +3285,9 @@ 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);
- int e_machine = thread ? thread__e_machine(thread, trace->host) : EM_HOST;
+ int e_machine = thread
+ ? thread__e_machine(thread, trace->host, /*e_flags=*/NULL)
+ : EM_HOST;
struct syscall *sc = trace__syscall_info(trace, evsel, e_machine, id);
if (sc) {
@@ -4916,7 +4918,7 @@ 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);
+ int e_machine = thread__e_machine(thread, trace->host, /*e_flags=*/NULL);
double ratio;
if (ttrace == NULL)
diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index c16c6dfaa959..880b1bd300c2 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -984,6 +984,7 @@ int thread__get_arch(struct thread *thread, const struct arch **parch)
{
const struct arch *arch;
struct machine *machine;
+ uint32_t e_flags;
uint16_t e_machine;
if (!thread) {
@@ -992,8 +993,8 @@ int thread__get_arch(struct thread *thread, const struct arch **parch)
}
machine = maps__machine(thread__maps(thread));
- e_machine = thread__e_machine(thread, machine);
- arch = arch__find(e_machine, machine->env ? machine->env->cpuid : NULL);
+ e_machine = thread__e_machine(thread, machine, &e_flags);
+ arch = arch__find(e_machine, e_flags, machine->env ? machine->env->cpuid : NULL);
if (arch == NULL) {
pr_err("%s: unsupported arch %d\n", __func__, e_machine);
return errno;
diff --git a/tools/perf/util/disasm.c b/tools/perf/util/disasm.c
index 9b0ba1fc5aec..6b36287f30fe 100644
--- a/tools/perf/util/disasm.c
+++ b/tools/perf/util/disasm.c
@@ -134,7 +134,7 @@ static int arch__cmp(const void *a, const void *b)
return e_machine_and_eflags__cmp(&(*aa)->id, &(*ab)->id);
}
-const struct arch *arch__find(uint16_t e_machine, const char *cpuid)
+const struct arch *arch__find(uint16_t e_machine, uint32_t e_flags, const char *cpuid)
{
static const struct arch *(*const arch_new_fn[])(const struct e_machine_and_e_flags *id,
const char *cpuid) = {
@@ -157,8 +157,7 @@ const struct arch *arch__find(uint16_t e_machine, const char *cpuid)
static size_t num_archs;
struct e_machine_and_e_flags key = {
.e_machine = e_machine,
- // TODO: e_flags should really come from the same source as e_machine.
- .e_flags = EF_HOST,
+ .e_flags = e_flags,
};
const struct arch *result = NULL, **tmp;
diff --git a/tools/perf/util/disasm.h b/tools/perf/util/disasm.h
index 6a1905f9d4fc..a6e478caf61a 100644
--- a/tools/perf/util/disasm.h
+++ b/tools/perf/util/disasm.h
@@ -108,7 +108,7 @@ struct annotate_args {
char *fileloc;
};
-const struct arch *arch__find(uint16_t e_machine, const char *cpuid);
+const struct arch *arch__find(uint16_t e_machine, uint32_t e_flags, const char *cpuid);
bool arch__is_x86(const struct arch *arch);
bool arch__is_powerpc(const struct arch *arch);
diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 91c9f7cb9d8c..b791e1b6b2cf 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -1220,14 +1220,20 @@ 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)
+uint16_t dso__read_e_machine(struct dso *optional_dso, int fd, uint32_t *e_flags)
{
uint16_t e_machine = EM_NONE;
unsigned char e_ident[EI_NIDENT];
enum dso_swap_type swap_type;
+ bool need_e_flags;
- _Static_assert(offsetof(Elf32_Ehdr, e_ident) == 0, "Unexpected offset");
- _Static_assert(offsetof(Elf64_Ehdr, e_ident) == 0, "Unexpected offset");
+ if (e_flags)
+ *e_flags = 0;
+
+ {
+ _Static_assert(offsetof(Elf32_Ehdr, e_ident) == 0, "Unexpected offset");
+ _Static_assert(offsetof(Elf64_Ehdr, e_ident) == 0, "Unexpected offset");
+ }
if (pread(fd, &e_ident, sizeof(e_ident), 0) != sizeof(e_ident))
return EM_NONE; // Read failed.
@@ -1254,18 +1260,35 @@ uint16_t dso__read_e_machine(struct dso *optional_dso, int fd)
{
_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))
- return EM_NONE; // e_machine read failed.
}
+ if (pread(fd, &e_machine, sizeof(e_machine), 18) != sizeof(e_machine))
+ return EM_NONE; // e_machine read failed.
e_machine = DSO_SWAP_TYPE__SWAP(swap_type, uint16_t, e_machine);
if (e_machine >= EM_NUM)
return EM_NONE; // Bad ELF machine number.
+#ifdef NDEBUG
+ /* In production code the e_flags are only needed on CSKY. */
+ need_e_flags = e_flags && e_machine == EM_CSKY;
+#else
+ /* Debug code will always read the e_flags. */
+ need_e_flags = e_flags != NULL;
+#endif
+ if (need_e_flags) {
+ off_t offset = e_ident[EI_CLASS] == ELFCLASS32
+ ? offsetof(Elf32_Ehdr, e_flags)
+ : offsetof(Elf64_Ehdr, e_flags);
+
+ if (pread(fd, e_flags, sizeof(*e_flags), offset) != sizeof(*e_flags)) {
+ *e_flags = 0;
+ return EM_NONE; // e_flags read failed.
+ }
+ }
return e_machine;
}
-uint16_t dso__e_machine(struct dso *dso, struct machine *machine)
+uint16_t dso__e_machine(struct dso *dso, struct machine *machine, uint32_t *e_flags)
{
uint16_t e_machine = EM_NONE;
int fd;
@@ -1285,6 +1308,8 @@ uint16_t dso__e_machine(struct dso *dso, struct machine *machine)
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;
case DSO_BINARY_TYPE__DEBUGLINK:
case DSO_BINARY_TYPE__BUILD_ID_CACHE:
@@ -1299,6 +1324,8 @@ uint16_t dso__e_machine(struct dso *dso, struct machine *machine)
break;
case DSO_BINARY_TYPE__NOT_FOUND:
default:
+ if (e_flags)
+ *e_flags = 0;
return EM_NONE;
}
@@ -1311,7 +1338,9 @@ uint16_t dso__e_machine(struct dso *dso, struct machine *machine)
try_to_open_dso(dso, machine);
fd = dso__data(dso)->fd;
if (fd >= 0)
- e_machine = dso__read_e_machine(dso, fd);
+ e_machine = dso__read_e_machine(dso, fd, e_flags);
+ else if (e_flags)
+ *e_flags = 0;
mutex_unlock(dso__data_open_lock());
return e_machine;
diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index a95fee7d634b..ede691e9a249 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -866,8 +866,8 @@ 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);
-uint16_t dso__e_machine(struct dso *dso, struct machine *machine);
+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);
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/scripting-engines/trace-event-python.c b/tools/perf/util/scripting-engines/trace-event-python.c
index b90edc147796..50f0d16520cc 100644
--- a/tools/perf/util/scripting-engines/trace-event-python.c
+++ b/tools/perf/util/scripting-engines/trace-event-python.c
@@ -925,7 +925,7 @@ static PyObject *get_perf_sample_dict(struct perf_sample *sample,
if (al->thread) {
machine = maps__machine(thread__maps(al->thread));
- e_machine = thread__e_machine(al->thread, machine);
+ e_machine = thread__e_machine(al->thread, machine, /*e_flags=*/NULL);
}
if (set_regs_in_dict(dict, sample, evsel, e_machine))
Py_FatalError("Failed to setting regs in dict");
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index c0231bc000e7..0e8a128d7c04 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1124,7 +1124,7 @@ static void dump_sample(struct machine *machine, struct evsel *evsel, union perf
if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_REGS_INTR)) {
struct thread *thread = machine__find_thread(machine, sample->pid, sample->pid);
- e_machine = thread__e_machine(thread, machine);
+ e_machine = thread__e_machine(thread, machine, /*e_flags=*/NULL);
}
printf("(IP, 0x%x): %d/%d: %#" PRIx64 " period: %" PRIu64 " addr: %#" PRIx64 "\n",
@@ -2965,7 +2965,7 @@ static int perf_session__e_machine_cb(struct thread *thread,
uint16_t *result = arg;
struct machine *machine = maps__machine(thread__maps(thread));
- *result = thread__e_machine(thread, machine);
+ *result = thread__e_machine(thread, machine, /*e_flags=*/NULL);
return *result != EM_NONE ? 1 : 0;
}
diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 3642858e6cbc..618f29afb160 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -449,7 +449,7 @@ void thread__find_cpumode_addr_location(struct thread *thread, u64 addr,
}
}
-static uint16_t read_proc_e_machine_for_pid(pid_t pid)
+static uint16_t read_proc_e_machine_for_pid(pid_t pid, uint32_t *e_flags)
{
char path[6 /* "/proc/" */ + 11 /* max length of pid */ + 5 /* "/exe\0" */];
int fd;
@@ -458,30 +458,46 @@ static uint16_t read_proc_e_machine_for_pid(pid_t pid)
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_machine = dso__read_e_machine(/*optional_dso=*/NULL, fd, e_flags);
close(fd);
}
return e_machine;
}
-static int thread__e_machine_callback(struct map *map, void *machine)
+struct thread__e_machine_callback_args {
+ struct machine *machine;
+ uint32_t e_flags;
+ uint16_t e_machine;
+};
+
+static int thread__e_machine_callback(struct map *map, void *_args)
{
+ struct thread__e_machine_callback_args *args = _args;
struct dso *dso = map__dso(map);
- _Static_assert(0 == EM_NONE, "Unexpected EM_NONE");
if (!dso)
- return EM_NONE;
+ return 0; // No dso, continue search.
- return dso__e_machine(dso, machine);
+ args->e_machine = dso__e_machine(dso, args->machine, &args->e_flags);
+ return args->e_machine != EM_NONE ? 1 /* stop search */ : 0 /* continue search */;
}
-uint16_t thread__e_machine(struct thread *thread, struct machine *machine)
+uint16_t thread__e_machine(struct thread *thread, struct machine *machine, uint32_t *e_flags)
{
pid_t tid, pid;
uint16_t e_machine = RC_CHK_ACCESS(thread)->e_machine;
+ uint32_t local_e_flags = 0;
+ struct thread__e_machine_callback_args args = {
+ .machine = machine,
+ .e_flags = 0,
+ .e_machine = EM_NONE,
+ };
- if (e_machine != EM_NONE)
+ if (e_machine != EM_NONE) {
+ if (e_flags)
+ *e_flags = thread__e_flags(thread);
return e_machine;
+ }
tid = thread__tid(thread);
pid = thread__pid(thread);
@@ -489,18 +505,19 @@ uint16_t thread__e_machine(struct thread *thread, struct machine *machine)
struct thread *parent = machine__findnew_thread(machine, pid, pid);
if (parent) {
- e_machine = thread__e_machine(parent, machine);
+ e_machine = thread__e_machine(parent, machine, &local_e_flags);
thread__put(parent);
- thread__set_e_machine(thread, e_machine);
- return e_machine;
+ goto out;
}
/* 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__for_each_map(thread__maps(thread), thread__e_machine_callback, &args);
+
+ if (args.e_machine != EM_NONE) {
+ e_machine = args.e_machine;
+ local_e_flags = args.e_flags;
+ } else {
/* Maps failed, perhaps we're live with map events disabled. */
bool is_live = machine->machines == NULL;
@@ -514,12 +531,18 @@ uint16_t thread__e_machine(struct thread *thread, struct machine *machine)
}
/* Read from /proc/pid/exe if live. */
if (is_live)
- e_machine = read_proc_e_machine_for_pid(pid);
+ e_machine = read_proc_e_machine_for_pid(pid, &local_e_flags);
}
- if (e_machine != EM_NONE)
+out:
+ if (e_machine != EM_NONE) {
thread__set_e_machine(thread, e_machine);
- else
+ thread__set_e_flags(thread, local_e_flags);
+ } else {
e_machine = EM_HOST;
+ local_e_flags = EF_HOST;
+ }
+ if (e_flags)
+ *e_flags = local_e_flags;
return e_machine;
}
diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
index 310eaea344bb..f5792d3e8a16 100644
--- a/tools/perf/util/thread.h
+++ b/tools/perf/util/thread.h
@@ -60,6 +60,10 @@ DECLARE_RC_STRUCT(thread) {
struct srccode_state srccode_state;
bool filter;
int filter_entry_depth;
+ /**
+ * @e_flags: The ELF EF_* associated with the thread. Valid if e_machine != EM_NONE.
+ */
+ uint16_t e_flags;
/**
* @e_machine: The ELF EM_* associated with the thread. EM_NONE if not
* computed.
@@ -307,13 +311,23 @@ 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);
+uint16_t thread__e_machine(struct thread *thread, struct machine *machine, uint32_t *e_flags);
static inline void thread__set_e_machine(struct thread *thread, uint16_t e_machine)
{
RC_CHK_ACCESS(thread)->e_machine = e_machine;
}
+static inline uint32_t thread__e_flags(const struct thread *thread)
+{
+ return RC_CHK_ACCESS(thread)->e_flags;
+}
+
+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__lbr_stitch_enable(const struct thread *thread)
{
diff --git a/tools/perf/util/unwind-libdw.c b/tools/perf/util/unwind-libdw.c
index 9cb0960ef905..3fdcfa06bf22 100644
--- a/tools/perf/util/unwind-libdw.c
+++ b/tools/perf/util/unwind-libdw.c
@@ -213,7 +213,7 @@ static bool memory_read(Dwfl *dwfl __maybe_unused, Dwarf_Addr addr, Dwarf_Word *
{
struct dwfl_ui_thread_info *dwfl_ui_ti = arg;
struct unwind_info *ui = dwfl_ui_ti->ui;
- uint16_t e_machine = thread__e_machine(ui->thread, ui->machine);
+ uint16_t e_machine = thread__e_machine(ui->thread, ui->machine, /*e_flags=*/NULL);
struct stack_dump *stack = &ui->sample->user_stack;
u64 start, end;
int offset;
@@ -348,7 +348,7 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
{
struct maps *maps = thread__maps(thread);
struct machine *machine = maps__machine(maps);
- uint16_t e_machine = thread__e_machine(thread, machine);
+ uint16_t e_machine = thread__e_machine(thread, machine, /*e_flags=*/NULL);
struct dwfl_ui_thread_info *dwfl_ui_ti;
static struct unwind_info *ui;
Dwfl *dwfl;
--
2.52.0.457.g6b5491de43-goog
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