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Diffstat (limited to '')
| -rw-r--r-- | tools/perf/tests/bp_signal.c | 313 |
1 files changed, 313 insertions, 0 deletions
diff --git a/tools/perf/tests/bp_signal.c b/tools/perf/tests/bp_signal.c new file mode 100644 index 000000000..cc9fbcedb --- /dev/null +++ b/tools/perf/tests/bp_signal.c @@ -0,0 +1,313 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Inspired by breakpoint overflow test done by + * Vince Weaver <vincent.weaver@maine.edu> for perf_event_tests + * (git://github.com/deater/perf_event_tests) + */ + +/* + * Powerpc needs __SANE_USERSPACE_TYPES__ before <linux/types.h> to select + * 'int-ll64.h' and avoid compile warnings when printing __u64 with %llu. + */ +#define __SANE_USERSPACE_TYPES__ + +#include <stdlib.h> +#include <stdio.h> +#include <unistd.h> +#include <string.h> +#include <sys/ioctl.h> +#include <time.h> +#include <fcntl.h> +#include <signal.h> +#include <sys/mman.h> +#include <linux/compiler.h> +#include <linux/hw_breakpoint.h> + +#include "tests.h" +#include "debug.h" +#include "event.h" +#include "perf-sys.h" +#include "cloexec.h" + +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 ( + ".pushsection .text;" + ".globl __test_function\n" + ".type __test_function, @function;" + "__test_function:\n" + "incq (%rdi)\n" + "ret\n" + ".popsection\n"); +#else +static void __test_function(volatile long *ptr) +{ + *ptr = 0x1234; +} +#endif + +static noinline 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) +{ + overflows++; + + if (overflows > 10) { + /* + * This should be executed only once during + * this test, if we are here for the 10th + * time, consider this the recursive issue. + * + * We can get out of here by disable events, + * so no new SIGIO is delivered. + */ + ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0); + ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0); + ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0); + } +} + +static int __event(bool is_x, void *addr, int sig) +{ + struct perf_event_attr pe; + int fd; + + memset(&pe, 0, sizeof(struct perf_event_attr)); + pe.type = PERF_TYPE_BREAKPOINT; + pe.size = sizeof(struct perf_event_attr); + + pe.config = 0; + 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; + pe.sample_type = PERF_SAMPLE_IP; + pe.wakeup_events = 1; + + pe.disabled = 1; + pe.exclude_kernel = 1; + pe.exclude_hv = 1; + + fd = sys_perf_event_open(&pe, 0, -1, -1, + perf_event_open_cloexec_flag()); + if (fd < 0) { + pr_debug("failed opening event %llx\n", pe.config); + return TEST_FAIL; + } + + fcntl(fd, F_SETFL, O_RDWR|O_NONBLOCK|O_ASYNC); + fcntl(fd, F_SETSIG, sig); + fcntl(fd, F_SETOWN, getpid()); + + ioctl(fd, PERF_EVENT_IOC_RESET, 0); + + return fd; +} + +static int bp_event(void *addr, int sig) +{ + return __event(true, addr, sig); +} + +static int wp_event(void *addr, int sig) +{ + return __event(false, addr, sig); +} + +static long long bp_count(int fd) +{ + long long count; + int ret; + + ret = read(fd, &count, sizeof(long long)); + if (ret != sizeof(long long)) { + pr_debug("failed to read: %d\n", ret); + return TEST_FAIL; + } + + return count; +} + +int test__bp_signal(struct test *test __maybe_unused, int subtest __maybe_unused) +{ + struct sigaction sa; + long long count1, count2, count3; + + /* setup SIGIO signal handler */ + memset(&sa, 0, sizeof(struct sigaction)); + sa.sa_sigaction = (void *) sig_handler; + sa.sa_flags = SA_SIGINFO; + + if (sigaction(SIGIO, &sa, NULL) < 0) { + pr_debug("failed setting up signal handler\n"); + 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 + * signal configured. We should get signal + * notification each time the breakpoint is hit + * + * 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: + * 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 + * exception being triggered receursively due to + * the wrong RF EFLAG management + * + * - we never trigger the sig_handler breakpoint due + * to the rong RF EFLAG management + * + */ + + 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' + * breakpoint. + */ + test_function(); + + 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, count3 %lld, overflow %d, overflows_2 %d\n", + count1, count2, count3, overflows, overflows_2); + + if (count1 != 1) { + if (count1 == 11) + pr_debug("failed: RF EFLAG recursion issue detected\n"); + else + pr_debug("failed: wrong count for bp1: %lld, expected 1\n", count1); + } + + if (overflows != 3) + pr_debug("failed: wrong overflow (%d) hit, expected 3\n", overflows); + + if (overflows_2 != 3) + pr_debug("failed: wrong overflow_2 (%d) hit, expected 3\n", overflows_2); + + if (count2 != 3) + pr_debug("failed: wrong count for bp2 (%lld), expected 3\n", count2); + + if (count3 != 2) + pr_debug("failed: wrong count for bp3 (%lld), expected 2\n", count3); + + return count1 == 1 && overflows == 3 && count2 == 3 && overflows_2 == 3 && count3 == 2 ? + TEST_OK : TEST_FAIL; +} + +bool test__bp_signal_is_supported(void) +{ + /* + * PowerPC and S390 do not support creation of instruction + * breakpoints using the perf_event interface. + * + * ARM requires explicit rounding down of the instruction + * pointer in Thumb mode, and then requires the single-step + * to be handled explicitly in the overflow handler to avoid + * stepping into the SIGIO handler and getting stuck on the + * breakpointed instruction. + * + * Since arm64 has the same issue with arm for the single-step + * handling, this case also gets stuck on the breakpointed + * instruction. + * + * Just disable the test for these architectures until these + * issues are resolved. + */ +#if defined(__powerpc__) || defined(__s390x__) || defined(__arm__) || \ + defined(__aarch64__) + return false; +#else + return true; +#endif +} |