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-rw-r--r--tools/perf/tests/bp_signal.c313
1 files changed, 313 insertions, 0 deletions
diff --git a/tools/perf/tests/bp_signal.c b/tools/perf/tests/bp_signal.c
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+++ b/tools/perf/tests/bp_signal.c
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+// 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
+}
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