Commit 8fd34e1c authored by Wang Nan's avatar Wang Nan Committed by Arnaldo Carvalho de Melo
Browse files

perf test: Improve bp_signal 

Will Deacon [1] has some question on patch [2]. This patch improves
test__bp_signal so we can test:

 1. A watchpoint and a breakpoint that fire on the same instruction
 2. Nested signals

Test result:

 On x86_64 and ARM64 (result are similar with patch [2] on ARM64):

  # ./perf test -v signal
  17: Test breakpoint overflow signal handler                  :
  --- start ---
  test child forked, pid 10213
  count1 1, count2 3, count3 2, overflow 3, overflows_2 3
  test child finished with 0
  ---- end ----
  Test breakpoint overflow signal handler: Ok

So at least 2 cases Will doubted are handled correctly.

[1] http://lkml.kernel.org/g/20160104165535.GI1616@arm.com
[2] http://lkml.kernel.org/g/1450921362-198371-1-git-send-email-wangnan0@huawei.com



Signed-off-by: default avatarWang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: He Kuang <hekuang@huawei.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1453715801-7732-9-git-send-email-wangnan0@huawei.com


Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 6a7d550e

tools/perf/tests/bp_signal.c

+118 −22
Original line number Diff line number Diff line
@@ -29,14 +29,59 @@ 


static int fd1;

static int fd2;

static int fd3;

static int overflows;

static int overflows_2;



volatile long the_var;





/*

 * Use ASM to ensure watchpoint and breakpoint can be triggered

 * at one instruction.

 */

#if defined (__x86_64__)

extern void __test_function(volatile long *ptr);

asm (

	".globl __test_function\n"

	"__test_function:\n"

	"incq (%rdi)\n"

	"ret\n");

#elif defined (__aarch64__)

extern void __test_function(volatile long *ptr);

asm (

	".globl __test_function\n"

	"__test_function:\n"

	"str x30, [x0]\n"

	"ret\n");



#else

static void __test_function(volatile long *ptr)

{

	*ptr = 0x1234;

}

#endif



__attribute__ ((noinline))

static int test_function(void)

{

	__test_function(&the_var);

	the_var++;

	return time(NULL);

}



static void sig_handler_2(int signum __maybe_unused,

			  siginfo_t *oh __maybe_unused,

			  void *uc __maybe_unused)

{

	overflows_2++;

	if (overflows_2 > 10) {

		ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);

		ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);

		ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);

	}

}



static void sig_handler(int signum __maybe_unused,

			siginfo_t *oh __maybe_unused,

			void *uc __maybe_unused)
@@ -54,10 +99,11 @@ static void sig_handler(int signum __maybe_unused, 
		 */

		ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);

		ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);

		ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);

	}

}



static int bp_event(void *fn, int setup_signal)

static int __event(bool is_x, void *addr, int signal)

{

	struct perf_event_attr pe;

	int fd;
@@ -67,8 +113,8 @@ static int bp_event(void *fn, int setup_signal) 
	pe.size = sizeof(struct perf_event_attr);



	pe.config = 0;

	pe.bp_type = HW_BREAKPOINT_X;

	pe.bp_addr = (unsigned long) fn;

	pe.bp_type = is_x ? HW_BREAKPOINT_X : HW_BREAKPOINT_W;

	pe.bp_addr = (unsigned long) addr;

	pe.bp_len = sizeof(long);



	pe.sample_period = 1;
@@ -86,17 +132,25 @@ static int bp_event(void *fn, int setup_signal) 
		return TEST_FAIL;

	}



	if (setup_signal) {

	fcntl(fd, F_SETFL, O_RDWR|O_NONBLOCK|O_ASYNC);

		fcntl(fd, F_SETSIG, SIGIO);

	fcntl(fd, F_SETSIG, signal);

	fcntl(fd, F_SETOWN, getpid());

	}



	ioctl(fd, PERF_EVENT_IOC_RESET, 0);



	return fd;

}



static int bp_event(void *addr, int signal)

{

	return __event(true, addr, signal);

}



static int wp_event(void *addr, int signal)

{

	return __event(false, addr, signal);

}



static long long bp_count(int fd)

{

	long long count;
@@ -114,7 +168,7 @@ static long long bp_count(int fd) 
int test__bp_signal(int subtest __maybe_unused)

{

	struct sigaction sa;

	long long count1, count2;

	long long count1, count2, count3;



	/* setup SIGIO signal handler */

	memset(&sa, 0, sizeof(struct sigaction));
@@ -126,21 +180,52 @@ int test__bp_signal(int subtest __maybe_unused) 
		return TEST_FAIL;

	}



	sa.sa_sigaction = (void *) sig_handler_2;

	if (sigaction(SIGUSR1, &sa, NULL) < 0) {

		pr_debug("failed setting up signal handler 2\n");

		return TEST_FAIL;

	}



	/*

	 * We create following events:

	 *

	 * fd1 - breakpoint event on test_function with SIGIO

	 * fd1 - breakpoint event on __test_function with SIGIO

	 *       signal configured. We should get signal

	 *       notification each time the breakpoint is hit

	 *

	 * fd2 - breakpoint event on sig_handler without SIGIO

	 * fd2 - breakpoint event on sig_handler with SIGUSR1

	 *       configured. We should get SIGUSR1 each time when

	 *       breakpoint is hit

	 *

	 * fd3 - watchpoint event on __test_function with SIGIO

	 *       configured.

	 *

	 * Following processing should happen:

	 *   - execute test_function

	 *   - fd1 event breakpoint hit -> count1 == 1

	 *   - SIGIO is delivered       -> overflows == 1

	 *   - fd2 event breakpoint hit -> count2 == 1

	 *   Exec:               Action:                       Result:

	 *   incq (%rdi)       - fd1 event breakpoint hit   -> count1 == 1

	 *                     - SIGIO is delivered

	 *   sig_handler       - fd2 event breakpoint hit   -> count2 == 1

	 *                     - SIGUSR1 is delivered

	 *   sig_handler_2                                  -> overflows_2 == 1  (nested signal)

	 *   sys_rt_sigreturn  - return from sig_handler_2

	 *   overflows++                                    -> overflows = 1

	 *   sys_rt_sigreturn  - return from sig_handler

	 *   incq (%rdi)       - fd3 event watchpoint hit   -> count3 == 1       (wp and bp in one insn)

	 *                     - SIGIO is delivered

	 *   sig_handler       - fd2 event breakpoint hit   -> count2 == 2

	 *                     - SIGUSR1 is delivered

	 *   sig_handler_2                                  -> overflows_2 == 2  (nested signal)

	 *   sys_rt_sigreturn  - return from sig_handler_2

	 *   overflows++                                    -> overflows = 2

	 *   sys_rt_sigreturn  - return from sig_handler

	 *   the_var++         - fd3 event watchpoint hit   -> count3 == 2       (standalone watchpoint)

	 *                     - SIGIO is delivered

	 *   sig_handler       - fd2 event breakpoint hit   -> count2 == 3

	 *                     - SIGUSR1 is delivered

	 *   sig_handler_2                                  -> overflows_2 == 3  (nested signal)

	 *   sys_rt_sigreturn  - return from sig_handler_2

	 *   overflows++                                    -> overflows == 3

	 *   sys_rt_sigreturn  - return from sig_handler

	 *

	 * The test case check following error conditions:

	 * - we get stuck in signal handler because of debug
@@ -152,11 +237,13 @@ int test__bp_signal(int subtest __maybe_unused) 
	 *

	 */



	fd1 = bp_event(test_function, 1);

	fd2 = bp_event(sig_handler, 0);

	fd1 = bp_event(__test_function, SIGIO);

	fd2 = bp_event(sig_handler, SIGUSR1);

	fd3 = wp_event((void *)&the_var, SIGIO);



	ioctl(fd1, PERF_EVENT_IOC_ENABLE, 0);

	ioctl(fd2, PERF_EVENT_IOC_ENABLE, 0);

	ioctl(fd3, PERF_EVENT_IOC_ENABLE, 0);



	/*

	 * Kick off the test by trigering 'fd1'
@@ -166,15 +253,18 @@ int test__bp_signal(int subtest __maybe_unused) 


	ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);

	ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);

	ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);



	count1 = bp_count(fd1);

	count2 = bp_count(fd2);

	count3 = bp_count(fd3);



	close(fd1);

	close(fd2);

	close(fd3);



	pr_debug("count1 %lld, count2 %lld, overflow %d\n",

		 count1, count2, overflows);

	pr_debug("count1 %lld, count2 %lld, count3 %lld, overflow %d, overflows_2 %d\n",

		 count1, count2, count3, overflows, overflows_2);



	if (count1 != 1) {

		if (count1 == 11)
@@ -183,12 +273,18 @@ int test__bp_signal(int subtest __maybe_unused) 
			pr_debug("failed: wrong count for bp1%lld\n", count1);

	}



	if (overflows != 1)

	if (overflows != 3)

		pr_debug("failed: wrong overflow hit\n");



	if (count2 != 1)

	if (overflows_2 != 3)

		pr_debug("failed: wrong overflow_2 hit\n");



	if (count2 != 3)

		pr_debug("failed: wrong count for bp2\n");



	return count1 == 1 && overflows == 1 && count2 == 1 ?

	if (count3 != 2)

		pr_debug("failed: wrong count for bp3\n");



	return count1 == 1 && overflows == 3 && count2 == 3 && overflows_2 == 3 && count3 == 2 ?

		TEST_OK : TEST_FAIL;

}

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