9 files changed, 187 insertions, 0 deletions

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 67d2a9003294..fa26865364b6 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -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 @@ out_child:
                 }
         }
 
+        perf_hooks__invoke_record_end();
+
         if (!err && !quiet) {
                 char samples[128];
                 const char *postfix = rec->timestamp_filename ?
diff --git a/tools/perf/tests/Build b/tools/perf/tests/Build
index 8a4ce492f7b2..af3ec94869aa 100644
--- a/tools/perf/tests/Build
+++ b/tools/perf/tests/Build
@@ -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)
diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c
index 778668a2a966..dab83f7042fa 100644
--- a/tools/perf/tests/builtin-test.c
+++ b/tools/perf/tests/builtin-test.c
@@ -230,6 +230,10 @@ static struct test generic_tests[] = {
                 .func = test__bitmap_print,
         },
         {
+                .desc = "Test perf hooks",
+                .func = test__perf_hooks,
+        },
+        {
                 .func = NULL,
         },
 };
diff --git a/tools/perf/tests/perf-hooks.c b/tools/perf/tests/perf-hooks.c
new file mode 100644
index 000000000000..9338cb2c25ab
--- /dev/null
+++ b/tools/perf/tests/perf-hooks.c
@@ -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;
+}
diff --git a/tools/perf/tests/tests.h b/tools/perf/tests/tests.h
index 7c196c585472..3a1f98f291ba 100644
--- a/tools/perf/tests/tests.h
+++ b/tools/perf/tests/tests.h
@@ -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
diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index 1dc67efad634..b2a47aac8d1c 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -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
diff --git a/tools/perf/util/perf-hooks-list.h b/tools/perf/util/perf-hooks-list.h
new file mode 100644
index 000000000000..2867c07ee84e
--- /dev/null
+++ b/tools/perf/util/perf-hooks-list.h
@@ -0,0 +1,3 @@
+PERF_HOOK(record_start)
+PERF_HOOK(record_end)
+PERF_HOOK(test)
diff --git a/tools/perf/util/perf-hooks.c b/tools/perf/util/perf-hooks.c
new file mode 100644
index 000000000000..4ce88e37dd63
--- /dev/null
+++ b/tools/perf/util/perf-hooks.c
@@ -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);
+}
diff --git a/tools/perf/util/perf-hooks.h b/tools/perf/util/perf-hooks.h
new file mode 100644
index 000000000000..1d482b26b4b9
--- /dev/null
+++ b/tools/perf/util/perf-hooks.h
@@ -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