perf tools: Pass context to perf hook functions

Pass a pointer to perf hook functions so they receive context
information during setup.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Joe Stringer <joe@ovn.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/20161126070354.141764-6-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/perf-hooks.c

@@ -15,13 +15,13 @@ static void sigsegv_handler(int sig __maybe_unused)
 	exit(-1);
 }
 
-static int hook_flags;
 
-static void the_hook(void)
+static void the_hook(void *_hook_flags)
 {
+	int *hook_flags = _hook_flags;
 	int *p = NULL;
 
-	hook_flags = 1234;
+	*hook_flags = 1234;
 
 	/* Generate a segfault, test perf_hooks__recover */
 	*p = 0;
@@ -29,13 +29,17 @@ static void the_hook(void)
 
 int test__perf_hooks(int subtest __maybe_unused)
 {
+	int hook_flags = 0;
+
 	signal(SIGSEGV, sigsegv_handler);
-	perf_hooks__set_hook("test", the_hook);
+	perf_hooks__set_hook("test", the_hook, &hook_flags);
 	perf_hooks__invoke_test();
 
 	/* hook is triggered? */
-	if (hook_flags != 1234)
+	if (hook_flags != 1234) {
+		pr_debug("Setting failed: %d (%p)\n", hook_flags, &hook_flags);
 		return TEST_FAIL;
+	}
 
 	/* the buggy hook is removed? */
 	if (perf_hooks__get_hook("test"))

tools/perf/util/perf-hooks.c

@@ -27,7 +27,7 @@ void perf_hooks__invoke(const struct perf_hook_desc *desc)
 		*(current_perf_hook->p_hook_func) = NULL;
 	} else {
 		current_perf_hook = desc;
-		(**desc->p_hook_func)();
+		(**desc->p_hook_func)(desc->hook_ctx);
 	}
 	current_perf_hook = NULL;
 }
@@ -41,7 +41,9 @@ void perf_hooks__recover(void)
 #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};
+	{.hook_name = #name,				\
+	 .p_hook_func = &__perf_hook_func_##name,	\
+	 .hook_ctx = NULL};
 #include "perf-hooks-list.h"
 #undef PERF_HOOK
 
@@ -54,7 +56,8 @@ static struct perf_hook_desc *perf_hooks[] = {
 #undef PERF_HOOK
 
 int perf_hooks__set_hook(const char *hook_name,
-			 perf_hook_func_t hook_func)
+			 perf_hook_func_t hook_func,
+			 void *hook_ctx)
 {
 	unsigned int i;
 
@@ -65,6 +68,7 @@ int perf_hooks__set_hook(const char *hook_name,
 		if (*(perf_hooks[i]->p_hook_func))
 			pr_warning("Overwrite existing hook: %s\n", hook_name);
 		*(perf_hooks[i]->p_hook_func) = hook_func;
+		perf_hooks[i]->hook_ctx = hook_ctx;
 		return 0;
 	}
 	return -ENOENT;

tools/perf/util/perf-hooks.h

@@ -5,10 +5,11 @@
 extern "C" {
 #endif
 
-typedef void (*perf_hook_func_t)(void);
+typedef void (*perf_hook_func_t)(void *ctx);
 struct perf_hook_desc {
 	const char * const hook_name;
 	perf_hook_func_t * const p_hook_func;
+	void *hook_ctx;
 };
 
 extern void perf_hooks__invoke(const struct perf_hook_desc *);
@@ -26,7 +27,8 @@ static inline void perf_hooks__invoke_##name(void)	\
 
 extern int
 perf_hooks__set_hook(const char *hook_name,
-		     perf_hook_func_t hook_func);
+		     perf_hook_func_t hook_func,
+		     void *hook_ctx);
 
 extern perf_hook_func_t
 perf_hooks__get_hook(const char *hook_name);