@@ -37,6 +37,7 @@
#include "util/llvm-utils.h"
#include "util/bpf-loader.h"
#include "util/trigger.h"
+#include "util/perf-hooks.h"
#include "asm/bug.h"
#include <unistd.h>
@@ -206,6 +207,12 @@ static void sig_handler(int sig)
done = 1;
}
+static void sigsegv_handler(int sig)
+{
+ perf_hooks__recover();
+ sighandler_dump_stack(sig);
+}
+
static void record__sig_exit(void)
{
if (signr == -1)
@@ -833,6 +840,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
signal(SIGCHLD, sig_handler);
signal(SIGINT, sig_handler);
signal(SIGTERM, sig_handler);
+ signal(SIGSEGV, sigsegv_handler);
if (rec->opts.auxtrace_snapshot_mode || rec->switch_output) {
signal(SIGUSR2, snapshot_sig_handler);
@@ -970,6 +978,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
trigger_ready(&auxtrace_snapshot_trigger);
trigger_ready(&switch_output_trigger);
+ perf_hooks__invoke_record_start();
for (;;) {
unsigned long long hits = rec->samples;
@@ -1114,6 +1123,8 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
}
}
+ perf_hooks__invoke_record_end();
+
if (!err && !quiet) {
char samples[128];
const char *postfix = rec->timestamp_filename ?
@@ -42,6 +42,7 @@ perf-y += backward-ring-buffer.o
perf-y += sdt.o
perf-y += is_printable_array.o
perf-y += bitmap.o
+perf-y += perf-hooks.o
$(OUTPUT)tests/llvm-src-base.c: tests/bpf-script-example.c tests/Build
$(call rule_mkdir)
@@ -230,6 +230,10 @@ static struct test generic_tests[] = {
.func = test__bitmap_print,
},
{
+ .desc = "Test perf hooks",
+ .func = test__perf_hooks,
+ },
+ {
.func = NULL,
},
};
new file mode 100644
@@ -0,0 +1,44 @@
+#include <signal.h>
+#include <stdlib.h>
+
+#include "tests.h"
+#include "debug.h"
+#include "util.h"
+#include "perf-hooks.h"
+
+static void sigsegv_handler(int sig __maybe_unused)
+{
+ pr_debug("SIGSEGV is observed as expected, try to recover.\n");
+ perf_hooks__recover();
+ signal(SIGSEGV, SIG_DFL);
+ raise(SIGSEGV);
+ exit(-1);
+}
+
+static int hook_flags;
+
+static void the_hook(void)
+{
+ int *p = NULL;
+
+ hook_flags = 1234;
+
+ /* Generate a segfault, test perf_hooks__recover */
+ *p = 0;
+}
+
+int test__perf_hooks(int subtest __maybe_unused)
+{
+ signal(SIGSEGV, sigsegv_handler);
+ perf_hooks__set_hook("test", the_hook);
+ perf_hooks__invoke_test();
+
+ /* hook is triggered? */
+ if (hook_flags != 1234)
+ return TEST_FAIL;
+
+ /* the buggy hook is removed? */
+ if (perf_hooks__get_hook("test"))
+ return TEST_FAIL;
+ return TEST_OK;
+}
@@ -91,6 +91,7 @@ int test__cpu_map_print(int subtest);
int test__sdt_event(int subtest);
int test__is_printable_array(int subtest);
int test__bitmap_print(int subtest);
+int test__perf_hooks(int subtest);
#if defined(__arm__) || defined(__aarch64__)
#ifdef HAVE_DWARF_UNWIND_SUPPORT
@@ -123,6 +123,8 @@ libperf-$(CONFIG_LIBELF) += genelf.o
libperf-$(CONFIG_DWARF) += genelf_debug.o
endif
+libperf-y += perf-hooks.o
+
CFLAGS_config.o += -DETC_PERFCONFIG="BUILD_STR($(ETC_PERFCONFIG_SQ))"
# avoid compiler warnings in 32-bit mode
CFLAGS_genelf_debug.o += -Wno-packed
new file mode 100644
@@ -0,0 +1,3 @@
+PERF_HOOK(record_start)
+PERF_HOOK(record_end)
+PERF_HOOK(test)
new file mode 100644
@@ -0,0 +1,84 @@
+/*
+ * perf_hooks.c
+ *
+ * Copyright (C) 2016 Wang Nan <wangnan0@huawei.com>
+ * Copyright (C) 2016 Huawei Inc.
+ */
+
+#include <errno.h>
+#include <stdlib.h>
+#include <setjmp.h>
+#include <linux/err.h>
+#include "util/util.h"
+#include "util/debug.h"
+#include "util/perf-hooks.h"
+
+static sigjmp_buf jmpbuf;
+static const struct perf_hook_desc *current_perf_hook;
+
+void perf_hooks__invoke(const struct perf_hook_desc *desc)
+{
+ if (!(desc && desc->p_hook_func && *desc->p_hook_func))
+ return;
+
+ if (sigsetjmp(jmpbuf, 1)) {
+ pr_warning("Fatal error (SEGFAULT) in perf hook '%s'\n",
+ desc->hook_name);
+ *(current_perf_hook->p_hook_func) = NULL;
+ } else {
+ current_perf_hook = desc;
+ (**desc->p_hook_func)();
+ }
+ current_perf_hook = NULL;
+}
+
+void perf_hooks__recover(void)
+{
+ if (current_perf_hook)
+ siglongjmp(jmpbuf, 1);
+}
+
+#define PERF_HOOK(name) \
+perf_hook_func_t __perf_hook_func_##name = NULL; \
+struct perf_hook_desc __perf_hook_desc_##name = \
+ {.hook_name = #name, .p_hook_func = &__perf_hook_func_##name};
+#include "perf-hooks-list.h"
+#undef PERF_HOOK
+
+#define PERF_HOOK(name) \
+ &__perf_hook_desc_##name,
+
+static struct perf_hook_desc *perf_hooks[] = {
+#include "perf-hooks-list.h"
+};
+#undef PERF_HOOK
+
+int perf_hooks__set_hook(const char *hook_name,
+ perf_hook_func_t hook_func)
+{
+ unsigned int i;
+
+ for (i = 0; i < ARRAY_SIZE(perf_hooks); i++) {
+ if (strcmp(hook_name, perf_hooks[i]->hook_name) != 0)
+ continue;
+
+ if (*(perf_hooks[i]->p_hook_func))
+ pr_warning("Overwrite existing hook: %s\n", hook_name);
+ *(perf_hooks[i]->p_hook_func) = hook_func;
+ return 0;
+ }
+ return -ENOENT;
+}
+
+perf_hook_func_t perf_hooks__get_hook(const char *hook_name)
+{
+ unsigned int i;
+
+ for (i = 0; i < ARRAY_SIZE(perf_hooks); i++) {
+ if (strcmp(hook_name, perf_hooks[i]->hook_name) != 0)
+ continue;
+
+ return *(perf_hooks[i]->p_hook_func);
+ }
+ return ERR_PTR(-ENOENT);
+}
new file mode 100644
@@ -0,0 +1,37 @@
+#ifndef PERF_UTIL_PERF_HOOKS_H
+#define PERF_UTIL_PERF_HOOKS_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef void (*perf_hook_func_t)(void);
+struct perf_hook_desc {
+ const char * const hook_name;
+ perf_hook_func_t * const p_hook_func;
+};
+
+extern void perf_hooks__invoke(const struct perf_hook_desc *);
+extern void perf_hooks__recover(void);
+
+#define PERF_HOOK(name) \
+extern struct perf_hook_desc __perf_hook_desc_##name; \
+static inline void perf_hooks__invoke_##name(void) \
+{ \
+ perf_hooks__invoke(&__perf_hook_desc_##name); \
+}
+
+#include "perf-hooks-list.h"
+#undef PERF_HOOK
+
+extern int
+perf_hooks__set_hook(const char *hook_name,
+ perf_hook_func_t hook_func);
+
+extern perf_hook_func_t
+perf_hooks__get_hook(const char *hook_name);
+
+#ifdef __cplusplus
+}
+#endif
+#endif