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authorArnaldo Carvalho de Melo <acme@redhat.com>2022-11-04 16:44:52 -0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2022-11-07 10:56:40 -0300
commita9cd6c6766857212894dd736d9f2bc29f1416f6a (patch)
treefe2acf0defc82e1e3e9e3a53785a1d58089dd929
parentb018899e620b8ee4529f43bd02e9e8e43043e33e (diff)
perf trace: Add BPF augmenter to perf_event_open()'s 'struct perf_event_attr' arg
Using BPF for that, doing a cleverish reuse of perf_event_attr__fprintf(), that really needs to be turned into __snprintf(), etc. But since the plan is to go the BTF way probably use libbpf's btf_dump__dump_type_data(). Example: [root@quaco ~]# perf trace -e ~acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c,perf_event_open --max-events 10 perf stat --quiet sleep 0.001 fg 0.000 perf_event_open(attr_uptr: { type: 1, size: 128, config: 0x1, sample_type: IDENTIFIER, read_format: TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING, disabled: 1, inherit: 1, enable_on_exec: 1, exclude_guest: 1 }, pid: 258859 (perf), cpu: -1, group_fd: -1, flags: FD_CLOEXEC) = 3 0.067 perf_event_open(attr_uptr: { type: 1, size: 128, config: 0x3, sample_type: IDENTIFIER, read_format: TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING, disabled: 1, inherit: 1, enable_on_exec: 1, exclude_guest: 1 }, pid: 258859 (perf), cpu: -1, group_fd: -1, flags: FD_CLOEXEC) = 4 0.120 perf_event_open(attr_uptr: { type: 1, size: 128, config: 0x4, sample_type: IDENTIFIER, read_format: TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING, disabled: 1, inherit: 1, enable_on_exec: 1, exclude_guest: 1 }, pid: 258859 (perf), cpu: -1, group_fd: -1, flags: FD_CLOEXEC) = 5 0.172 perf_event_open(attr_uptr: { type: 1, size: 128, config: 0x2, sample_type: IDENTIFIER, read_format: TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING, disabled: 1, inherit: 1, enable_on_exec: 1, exclude_guest: 1 }, pid: 258859 (perf), cpu: -1, group_fd: -1, flags: FD_CLOEXEC) = 7 0.190 perf_event_open(attr_uptr: { size: 128, sample_type: IDENTIFIER, read_format: TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING, disabled: 1, inherit: 1, enable_on_exec: 1, exclude_guest: 1 }, pid: 258859 (perf), cpu: -1, group_fd: -1, flags: FD_CLOEXEC) = 8 0.199 perf_event_open(attr_uptr: { size: 128, config: 0x1, sample_type: IDENTIFIER, read_format: TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING, disabled: 1, inherit: 1, enable_on_exec: 1, exclude_guest: 1 }, pid: 258859 (perf), cpu: -1, group_fd: -1, flags: FD_CLOEXEC) = 9 0.204 perf_event_open(attr_uptr: { size: 128, config: 0x4, sample_type: IDENTIFIER, read_format: TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING, disabled: 1, inherit: 1, enable_on_exec: 1, exclude_guest: 1 }, pid: 258859 (perf), cpu: -1, group_fd: -1, flags: FD_CLOEXEC) = 10 0.210 perf_event_open(attr_uptr: { size: 128, config: 0x5, sample_type: IDENTIFIER, read_format: TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING, disabled: 1, inherit: 1, enable_on_exec: 1, exclude_guest: 1 }, pid: 258859 (perf), cpu: -1, group_fd: -1, flags: FD_CLOEXEC) = 11 [root@quaco ~]# Suggested-by: Ian Rogers <irogers@google.com> Tested-by: Ian Rogers <irogers@google.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Link: https://lore.kernel.org/r/Y2V2Tpu+2vzJyon2@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
-rw-r--r--tools/perf/builtin-trace.c3
-rw-r--r--tools/perf/examples/bpf/augmented_raw_syscalls.c44
-rw-r--r--tools/perf/trace/beauty/perf_event_open.c44
3 files changed, 90 insertions, 1 deletions
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 72991528687e..5690c33c523b 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -1053,7 +1053,8 @@ static struct syscall_fmt syscall_fmts[] = {
.arg = { [0] = { .scnprintf = SCA_FDAT, /* dfd */ },
[2] = { .scnprintf = SCA_OPEN_FLAGS, /* flags */ }, }, },
{ .name = "perf_event_open",
- .arg = { [2] = { .scnprintf = SCA_INT, /* cpu */ },
+ .arg = { [0] = { .scnprintf = SCA_PERF_ATTR, /* attr */ },
+ [2] = { .scnprintf = SCA_INT, /* cpu */ },
[3] = { .scnprintf = SCA_FD, /* group_fd */ },
[4] = { .scnprintf = SCA_PERF_FLAGS, /* flags */ }, }, },
{ .name = "pipe2",
diff --git a/tools/perf/examples/bpf/augmented_raw_syscalls.c b/tools/perf/examples/bpf/augmented_raw_syscalls.c
index 926238efd7d8..0599823e8ae1 100644
--- a/tools/perf/examples/bpf/augmented_raw_syscalls.c
+++ b/tools/perf/examples/bpf/augmented_raw_syscalls.c
@@ -129,6 +129,7 @@ struct augmented_args_payload {
struct augmented_arg arg, arg2;
};
struct sockaddr_storage saddr;
+ char __data[sizeof(struct augmented_arg)];
};
};
@@ -293,6 +294,49 @@ int sys_enter_renameat(struct syscall_enter_args *args)
return augmented__output(args, augmented_args, len);
}
+#define PERF_ATTR_SIZE_VER0 64 /* sizeof first published struct */
+
+// we need just the start, get the size to then copy it
+struct perf_event_attr_size {
+ __u32 type;
+ /*
+ * Size of the attr structure, for fwd/bwd compat.
+ */
+ __u32 size;
+};
+
+SEC("!syscalls:sys_enter_perf_event_open")
+int sys_enter_perf_event_open(struct syscall_enter_args *args)
+{
+ struct augmented_args_payload *augmented_args = augmented_args_payload();
+ const struct perf_event_attr_size *attr = (const struct perf_event_attr_size *)args->args[0], *attr_read;
+ unsigned int len = sizeof(augmented_args->args);
+
+ if (augmented_args == NULL)
+ goto failure;
+
+ if (bpf_probe_read(&augmented_args->__data, sizeof(*attr), attr) < 0)
+ goto failure;
+
+ attr_read = (const struct perf_event_attr_size *)augmented_args->__data;
+
+ __u32 size = attr_read->size;
+
+ if (!size)
+ size = PERF_ATTR_SIZE_VER0;
+
+ if (size > sizeof(augmented_args->__data))
+ goto failure;
+
+ // Now that we read attr->size and tested it against the size limits, read it completely
+ if (bpf_probe_read(&augmented_args->__data, size, attr) < 0)
+ goto failure;
+
+ return augmented__output(args, augmented_args, len + size);
+failure:
+ return 1; /* Failure: don't filter */
+}
+
static pid_t getpid(void)
{
return bpf_get_current_pid_tgid();
diff --git a/tools/perf/trace/beauty/perf_event_open.c b/tools/perf/trace/beauty/perf_event_open.c
index 11d47dbe63bd..01ee15fe9d0c 100644
--- a/tools/perf/trace/beauty/perf_event_open.c
+++ b/tools/perf/trace/beauty/perf_event_open.c
@@ -44,3 +44,47 @@ static size_t syscall_arg__scnprintf_perf_flags(char *bf, size_t size,
}
#define SCA_PERF_FLAGS syscall_arg__scnprintf_perf_flags
+
+struct attr_fprintf_args {
+ size_t size, printed;
+ char *bf;
+ bool first;
+};
+
+static int attr__fprintf(FILE *fp __maybe_unused, const char *name, const char *val, void *priv)
+{
+ struct attr_fprintf_args *args = priv;
+ size_t printed = scnprintf(args->bf + args->printed , args->size - args->printed, "%s%s: %s", args->first ? "" : ", ", name, val);
+
+ args->first = false;
+ args->printed += printed;
+ return printed;
+}
+
+static size_t perf_event_attr___scnprintf(struct perf_event_attr *attr, char *bf, size_t size, bool show_zeros __maybe_unused)
+{
+ struct attr_fprintf_args args = {
+ .printed = scnprintf(bf, size, "{ "),
+ .size = size,
+ .first = true,
+ .bf = bf,
+ };
+
+ perf_event_attr__fprintf(stdout, attr, attr__fprintf, &args);
+ return args.printed + scnprintf(bf + args.printed, size - args.printed, " }");
+}
+
+static size_t syscall_arg__scnprintf_augmented_perf_event_attr(struct syscall_arg *arg, char *bf, size_t size)
+{
+ return perf_event_attr___scnprintf((void *)arg->augmented.args, bf, size, arg->trace->show_zeros);
+}
+
+static size_t syscall_arg__scnprintf_perf_event_attr(char *bf, size_t size, struct syscall_arg *arg)
+{
+ if (arg->augmented.args)
+ return syscall_arg__scnprintf_augmented_perf_event_attr(arg, bf, size);
+
+ return scnprintf(bf, size, "%#lx", arg->val);
+}
+
+#define SCA_PERF_ATTR syscall_arg__scnprintf_perf_event_attr