1 files changed, 206 insertions, 0 deletions
diff --git a/tools/perf/tests/bp_account.c b/tools/perf/tests/bp_account.c
new file mode 100644
index 000000000..489b50604
--- /dev/null
+++ b/tools/perf/tests/bp_account.c
@@ -0,0 +1,206 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 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 <fcntl.h>
+#include <linux/hw_breakpoint.h>
+
+#include "tests.h"
+#include "debug.h"
+#include "event.h"
+#include "../perf-sys.h"
+#include "cloexec.h"
+
+static volatile long the_var;
+
+static noinline int test_function(void)
+{
+	return 0;
+}
+
+static int __event(bool is_x, void *addr, struct perf_event_attr *attr)
+{
+	int fd;
+
+	memset(attr, 0, sizeof(struct perf_event_attr));
+	attr->type = PERF_TYPE_BREAKPOINT;
+	attr->size = sizeof(struct perf_event_attr);
+
+	attr->config = 0;
+	attr->bp_type = is_x ? HW_BREAKPOINT_X : HW_BREAKPOINT_W;
+	attr->bp_addr = (unsigned long) addr;
+	attr->bp_len = sizeof(long);
+
+	attr->sample_period = 1;
+	attr->sample_type = PERF_SAMPLE_IP;
+
+	attr->exclude_kernel = 1;
+	attr->exclude_hv = 1;
+
+	fd = sys_perf_event_open(attr, -1, 0, -1,
+				 perf_event_open_cloexec_flag());
+	if (fd < 0) {
+		pr_debug("failed opening event %llx\n", attr->config);
+		return TEST_FAIL;
+	}
+
+	return fd;
+}
+
+static int wp_event(void *addr, struct perf_event_attr *attr)
+{
+	return __event(false, addr, attr);
+}
+
+static int bp_event(void *addr, struct perf_event_attr *attr)
+{
+	return __event(true, addr, attr);
+}
+
+static int bp_accounting(int wp_cnt, int share)
+{
+	struct perf_event_attr attr, attr_mod, attr_new;
+	int i, fd[wp_cnt], fd_wp, ret;
+
+	for (i = 0; i < wp_cnt; i++) {
+		fd[i] = wp_event((void *)&the_var, &attr);
+		TEST_ASSERT_VAL("failed to create wp\n", fd[i] != -1);
+		pr_debug("wp %d created\n", i);
+	}
+
+	attr_mod = attr;
+	attr_mod.bp_type = HW_BREAKPOINT_X;
+	attr_mod.bp_addr = (unsigned long) test_function;
+
+	ret = ioctl(fd[0], PERF_EVENT_IOC_MODIFY_ATTRIBUTES, &attr_mod);
+	TEST_ASSERT_VAL("failed to modify wp\n", ret == 0);
+
+	pr_debug("wp 0 modified to bp\n");
+
+	if (!share) {
+		fd_wp = wp_event((void *)&the_var, &attr_new);
+		TEST_ASSERT_VAL("failed to create max wp\n", fd_wp != -1);
+		pr_debug("wp max created\n");
+	}
+
+	for (i = 0; i < wp_cnt; i++)
+		close(fd[i]);
+
+	return 0;
+}
+
+static int detect_cnt(bool is_x)
+{
+	struct perf_event_attr attr;
+	void *addr = is_x ? (void *)test_function : (void *)&the_var;
+	int fd[100], cnt = 0, i;
+
+	while (1) {
+		if (cnt == 100) {
+			pr_debug("way too many debug registers, fix the test\n");
+			return 0;
+		}
+		fd[cnt] = __event(is_x, addr, &attr);
+
+		if (fd[cnt] < 0)
+			break;
+		cnt++;
+	}
+
+	for (i = 0; i < cnt; i++)
+		close(fd[i]);
+
+	return cnt;
+}
+
+static int detect_ioctl(void)
+{
+	struct perf_event_attr attr;
+	int fd, ret = 1;
+
+	fd = wp_event((void *) &the_var, &attr);
+	if (fd > 0) {
+		ret = ioctl(fd, PERF_EVENT_IOC_MODIFY_ATTRIBUTES, &attr);
+		close(fd);
+	}
+
+	return ret ? 0 : 1;
+}
+
+static int detect_share(int wp_cnt, int bp_cnt)
+{
+	struct perf_event_attr attr;
+	int i, fd[wp_cnt + bp_cnt], ret;
+
+	for (i = 0; i < wp_cnt; i++) {
+		fd[i] = wp_event((void *)&the_var, &attr);
+		TEST_ASSERT_VAL("failed to create wp\n", fd[i] != -1);
+	}
+
+	for (; i < (bp_cnt + wp_cnt); i++) {
+		fd[i] = bp_event((void *)test_function, &attr);
+		if (fd[i] == -1)
+			break;
+	}
+
+	ret = i != (bp_cnt + wp_cnt);
+
+	while (i--)
+		close(fd[i]);
+
+	return ret;
+}
+
+/*
+ * This test does following:
+ *   - detects the number of watch/break-points,
+ *     skip test if any is missing
+ *   - detects PERF_EVENT_IOC_MODIFY_ATTRIBUTES ioctl,
+ *     skip test if it's missing
+ *   - detects if watchpoints and breakpoints share
+ *     same slots
+ *   - create all possible watchpoints on cpu 0
+ *   - change one of it to breakpoint
+ *   - in case wp and bp do not share slots,
+ *     we create another watchpoint to ensure
+ *     the slot accounting is correct
+ */
+int test__bp_accounting(struct test *test __maybe_unused, int subtest __maybe_unused)
+{
+	int has_ioctl = detect_ioctl();
+	int wp_cnt = detect_cnt(false);
+	int bp_cnt = detect_cnt(true);
+	int share  = detect_share(wp_cnt, bp_cnt);
+
+	pr_debug("watchpoints count %d, breakpoints count %d, has_ioctl %d, share %d\n",
+		 wp_cnt, bp_cnt, has_ioctl, share);
+
+	if (!wp_cnt || !bp_cnt || !has_ioctl)
+		return TEST_SKIP;
+
+	return bp_accounting(wp_cnt, share);
+}
+
+bool test__bp_account_is_supported(void)
+{
+	/*
+	 * PowerPC and S390 do not support creation of instruction
+	 * breakpoints using the perf_event interface.
+	 *
+	 * Just disable the test for these architectures until these
+	 * issues are resolved.
+	 */
+#if defined(__powerpc__) || defined(__s390x__)
+	return false;
+#else
+	return true;
+#endif
+}