From: Wang Nan <wangnan0@huawei.com>
To: <acme@redhat.com>, <ast@fb.com>
Cc: <lizefan@huawei.com>, <hekuang@huawei.com>,
<linux-kernel@vger.kernel.org>, <pi3orama@163.com>,
Wang Nan <wangnan0@huawei.com>, Jiri Olsa <jolsa@kernel.org>
Subject: [PATCH 08/34] perf tools: Introduce perf hooks
Date: Tue, 15 Nov 2016 04:05:51 +0000 [thread overview]
Message-ID: <20161115040617.69788-9-wangnan0@huawei.com> (raw)
In-Reply-To: <20161115040617.69788-1-wangnan0@huawei.com>
Perf hooks allow hooking user code at perf events. They can be used for
manipulation of BPF maps, taking snapshot and reporting results. In this
patch two perf hook points are introduced: record_start and record_end.
To avoid buggy user actions, a SIGSEGV signal handler is introduced into
'perf record'. It turns off perf hook if it causes a segfault and report
an error to help debugging.
A test case for perf hook is introduced.
Test result:
$ ./buildperf/perf test -v hook
50: Test perf hooks :
--- start ---
test child forked, pid 10311
SIGSEGV is observed as expected, try to recover.
Fatal error (SEGFAULT) in perf hook 'test'
test child finished with 0
---- end ----
Test perf hooks: Ok
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
---
tools/perf/builtin-record.c | 11 +++++
tools/perf/tests/Build | 1 +
tools/perf/tests/builtin-test.c | 4 ++
tools/perf/tests/perf-hooks.c | 44 ++++++++++++++++++++
tools/perf/tests/tests.h | 1 +
tools/perf/util/Build | 2 +
tools/perf/util/perf-hooks-list.h | 3 ++
tools/perf/util/perf-hooks.c | 84 +++++++++++++++++++++++++++++++++++++++
tools/perf/util/perf-hooks.h | 37 +++++++++++++++++
9 files changed, 187 insertions(+)
create mode 100644 tools/perf/tests/perf-hooks.c
create mode 100644 tools/perf/util/perf-hooks-list.h
create mode 100644 tools/perf/util/perf-hooks.c
create mode 100644 tools/perf/util/perf-hooks.h
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 67d2a90..fa26865 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 @@ 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 ?
diff --git a/tools/perf/tests/Build b/tools/perf/tests/Build
index 8a4ce49..af3ec94 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 778668a..dab83f7 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 0000000..9338cb2
--- /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 7c196c5..3a1f98f 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 1dc67ef..b2a47aa 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 0000000..2867c07
--- /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 0000000..4ce88e3
--- /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 0000000..1d482b2
--- /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
--
2.10.1
next prev parent reply other threads:[~2016-11-15 4:14 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-15 4:05 [PATCH 00/34] perf clang: Builtin clang and perfhook support Wang Nan
2016-11-15 4:05 ` [PATCH 01/34] perf tools: Fix kernel version error in ubuntu Wang Nan
2016-11-25 17:20 ` [tip:perf/core] " tip-bot for Wang Nan
2016-11-15 4:05 ` [PATCH 02/34] perf record: Fix segfault when running with suid and kptr_restrict is 1 Wang Nan
2016-11-25 17:21 ` [tip:perf/core] " tip-bot for Wang Nan
2016-11-15 4:05 ` [PATCH 03/34] tools perf: Add missing struct defeinition in probe_event.h Wang Nan
2016-11-25 17:21 ` [tip:perf/core] perf tools: Add missing struct definition " tip-bot for Wang Nan
2016-11-15 4:05 ` [PATCH 04/34] tools lib bpf: fix maps resolution Wang Nan
2016-11-25 17:22 ` [tip:perf/core] tools lib bpf: Fix " tip-bot for Eric Leblond
2016-11-15 4:05 ` [PATCH 05/34] tools lib bpf: Add missing bpf map functions Wang Nan
2016-11-17 3:23 ` Wangnan (F)
2016-11-25 14:31 ` Arnaldo Carvalho de Melo
2016-11-15 4:05 ` [PATCH 06/34] tools lib bpf: Add private field for bpf_object Wang Nan
2016-11-15 4:05 ` [PATCH 07/34] tools lib bpf: Retrive bpf_map through offset of bpf_map_def Wang Nan
2016-11-15 4:05 ` Wang Nan [this message]
2016-11-15 4:05 ` [PATCH 09/34] perf tools: Pass context to perf hook functions Wang Nan
2016-11-15 4:05 ` [PATCH 10/34] perf llvm: Extract helpers in llvm-utils.c Wang Nan
2016-11-15 4:05 ` [PATCH 11/34] tools build: Add feature detection for LLVM Wang Nan
2016-11-15 4:05 ` [PATCH 12/34] tools build: Add feature detection for clang Wang Nan
2016-11-15 4:05 ` [PATCH 13/34] perf build: Add clang and llvm compile and linking support Wang Nan
2016-11-15 4:05 ` [PATCH 14/34] perf clang: Add builtin clang support ant test case Wang Nan
2016-11-15 4:05 ` [PATCH 15/34] perf clang: Use real file system for #include Wang Nan
2016-11-15 4:05 ` [PATCH 16/34] perf clang: Allow passing CFLAGS to builtin clang Wang Nan
2016-11-15 4:06 ` [PATCH 17/34] perf clang: Update test case to use real BPF script Wang Nan
2016-11-15 4:06 ` [PATCH 18/34] perf clang: Support compile IR to BPF object and add testcase Wang Nan
2016-11-15 4:06 ` [PATCH 19/34] perf clang: Compile BPF script use builtin clang support Wang Nan
2016-11-15 4:06 ` [PATCH 20/34] perf clang: Pass full path to builtin clang Wang Nan
2016-11-15 4:06 ` [PATCH 21/34] perf clang: Pass CFLAGS " Wang Nan
2016-11-15 4:06 ` [PATCH 22/34] perf clang jit: Wrap llvm::Module using PerfModule Wang Nan
2016-11-15 4:06 ` [PATCH 23/34] perf clang jit: Insignt BPF and JIT functions in a Module Wang Nan
2016-11-15 4:06 ` [PATCH 24/34] perf clang jit: add PerfModule::doJIT to JIT perfhook functions Wang Nan
2016-11-15 4:06 ` [PATCH 25/34] perf clang jit: Export functions for jitted code Wang Nan
2016-11-15 4:06 ` [PATCH 26/34] perf clang jit: Actually JIT and hook in bpf loader Wang Nan
2016-11-15 4:06 ` [PATCH 27/34] perf clang jit: Collect the lowest address in maps section as map_base Wang Nan
2016-11-15 4:06 ` [PATCH 28/34] perf clang jit: Access BPF map Wang Nan
2016-11-15 4:06 ` [PATCH 29/34] perf clang jit: Allow jitted perf hook access BPF maps Wang Nan
2016-11-15 4:06 ` [PATCH 30/34] perf clang: Link BPF functions declaration into perf Wang Nan
2016-11-15 4:06 ` [PATCH 31/34] perf clang: Declare BPF functions for BPF scripts automatically Wang Nan
2016-11-15 4:06 ` [PATCH 32/34] perf clang: Include helpers to BPF scripts Wang Nan
2016-11-15 4:06 ` [PATCH 33/34] perf clang builtin: Define hook helpers by default Wang Nan
2016-11-15 4:06 ` [PATCH 34/34] perf clang git: Export getpid() to perf hook Wang Nan
2016-11-15 4:32 ` [PATCH 00/34] perf clang: Builtin clang and perfhook support Wangnan (F)
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