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perf test: Improve bp_signal
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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: Wang 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: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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@WangNan0 @acmel
WangNan0 authored and acmel committed Jan 29, 2016
1 parent 6a7d550 commit 8fd34e1
Showing 1 changed file with 118 additions and 22 deletions.
140 changes: 118 additions & 22 deletions tools/perf/tests/bp_signal.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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)
Expand All @@ -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;
Expand All @@ -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;
Expand All @@ -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_SETOWN, getpid());
}
fcntl(fd, F_SETFL, O_RDWR|O_NONBLOCK|O_ASYNC);
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;
Expand All @@ -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));
Expand All @@ -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
Expand All @@ -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'
Expand All @@ -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)
Expand All @@ -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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