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Date: Mon, 11 Jan 2016 18:37:29 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Wang Nan <wangnan0@...wei.com>
Cc: linux-kernel@...r.kernel.org, pi3orama@....com, lizefan@...wei.com,
netdev@...r.kernel.org, davem@...emloft.net,
Will Deacon <will.deacon@....com>, Jiri Olsa <jolsa@...nel.org>
Subject: Re: [PATCH 17/53] perf test: Improve bp_signal
Em Mon, Jan 11, 2016 at 01:48:08PM +0000, Wang Nan escreveu:
> 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@...wei.com>
> Cc: Will Deacon <will.deacon@....com>
Will, are you ok with this one? Can I have an Acked-by or better,
Tested-by for the AARCH64 base?
IIRC Jiri made some comment about this one?
- Arnaldo
> Cc: Jiri Olsa <jolsa@...nel.org>
> Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
> ---
> tools/perf/tests/bp_signal.c | 140 ++++++++++++++++++++++++++++++++++++-------
> 1 file changed, 118 insertions(+), 22 deletions(-)
>
> diff --git a/tools/perf/tests/bp_signal.c b/tools/perf/tests/bp_signal.c
> index fb80c9e..1d1bb48 100644
> --- a/tools/perf/tests/bp_signal.c
> +++ b/tools/perf/tests/bp_signal.c
> @@ -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_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;
> @@ -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;
> }
> --
> 1.8.3.4
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