powerpc/watchpoint: Add DAR outside test in perf-hwbreak.c selftest

So far we used to ignore exception if DAR points outside of user
specified range. But now we are ignoring it only if actual load/store
range does not overlap with user specified range. Include selftests
for the same:

  # ./tools/testing/selftests/powerpc/ptrace/perf-hwbreak
  ...
  TESTED: No overlap
  TESTED: Partial overlap
  TESTED: Partial overlap
  TESTED: No overlap
  TESTED: Full overlap
  success: perf_hwbreak
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191017093204.7511-7-ravi.bangoria@linux.ibm.com

tools/testing/selftests/powerpc/ptrace/perf-hwbreak.c

@@ -148,6 +148,121 @@ static int runtestsingle(int readwriteflag, int exclude_user, int arraytest)
 	return 0;
 }
 
+static int runtest_dar_outside(void)
+{
+	void *target;
+	volatile __u16 temp16;
+	volatile __u64 temp64;
+	struct perf_event_attr attr;
+	int break_fd;
+	unsigned long long breaks;
+	int fail = 0;
+	size_t res;
+
+	target = malloc(8);
+	if (!target) {
+		perror("malloc failed");
+		exit(EXIT_FAILURE);
+	}
+
+	/* setup counters */
+	memset(&attr, 0, sizeof(attr));
+	attr.disabled = 1;
+	attr.type = PERF_TYPE_BREAKPOINT;
+	attr.exclude_kernel = 1;
+	attr.exclude_hv = 1;
+	attr.exclude_guest = 1;
+	attr.bp_type = HW_BREAKPOINT_RW;
+	/* watch middle half of target array */
+	attr.bp_addr = (__u64)(target + 2);
+	attr.bp_len = 4;
+	break_fd = sys_perf_event_open(&attr, 0, -1, -1, 0);
+	if (break_fd < 0) {
+		free(target);
+		perror("sys_perf_event_open");
+		exit(EXIT_FAILURE);
+	}
+
+	/* Shouldn't hit. */
+	ioctl(break_fd, PERF_EVENT_IOC_RESET);
+	ioctl(break_fd, PERF_EVENT_IOC_ENABLE);
+	temp16 = *((__u16 *)target);
+	*((__u16 *)target) = temp16;
+	ioctl(break_fd, PERF_EVENT_IOC_DISABLE);
+	res = read(break_fd, &breaks, sizeof(unsigned long long));
+	assert(res == sizeof(unsigned long long));
+	if (breaks == 0) {
+		printf("TESTED: No overlap\n");
+	} else {
+		printf("FAILED: No overlap: %lld != 0\n", breaks);
+		fail = 1;
+	}
+
+	/* Hit */
+	ioctl(break_fd, PERF_EVENT_IOC_RESET);
+	ioctl(break_fd, PERF_EVENT_IOC_ENABLE);
+	temp16 = *((__u16 *)(target + 1));
+	*((__u16 *)(target + 1)) = temp16;
+	ioctl(break_fd, PERF_EVENT_IOC_DISABLE);
+	res = read(break_fd, &breaks, sizeof(unsigned long long));
+	assert(res == sizeof(unsigned long long));
+	if (breaks == 2) {
+		printf("TESTED: Partial overlap\n");
+	} else {
+		printf("FAILED: Partial overlap: %lld != 2\n", breaks);
+		fail = 1;
+	}
+
+	/* Hit */
+	ioctl(break_fd, PERF_EVENT_IOC_RESET);
+	ioctl(break_fd, PERF_EVENT_IOC_ENABLE);
+	temp16 = *((__u16 *)(target + 5));
+	*((__u16 *)(target + 5)) = temp16;
+	ioctl(break_fd, PERF_EVENT_IOC_DISABLE);
+	res = read(break_fd, &breaks, sizeof(unsigned long long));
+	assert(res == sizeof(unsigned long long));
+	if (breaks == 2) {
+		printf("TESTED: Partial overlap\n");
+	} else {
+		printf("FAILED: Partial overlap: %lld != 2\n", breaks);
+		fail = 1;
+	}
+
+	/* Shouldn't Hit */
+	ioctl(break_fd, PERF_EVENT_IOC_RESET);
+	ioctl(break_fd, PERF_EVENT_IOC_ENABLE);
+	temp16 = *((__u16 *)(target + 6));
+	*((__u16 *)(target + 6)) = temp16;
+	ioctl(break_fd, PERF_EVENT_IOC_DISABLE);
+	res = read(break_fd, &breaks, sizeof(unsigned long long));
+	assert(res == sizeof(unsigned long long));
+	if (breaks == 0) {
+		printf("TESTED: No overlap\n");
+	} else {
+		printf("FAILED: No overlap: %lld != 0\n", breaks);
+		fail = 1;
+	}
+
+	/* Hit */
+	ioctl(break_fd, PERF_EVENT_IOC_RESET);
+	ioctl(break_fd, PERF_EVENT_IOC_ENABLE);
+	temp64 = *((__u64 *)target);
+	*((__u64 *)target) = temp64;
+	ioctl(break_fd, PERF_EVENT_IOC_DISABLE);
+	res = read(break_fd, &breaks, sizeof(unsigned long long));
+	assert(res == sizeof(unsigned long long));
+	if (breaks == 2) {
+		printf("TESTED: Full overlap\n");
+	} else {
+		printf("FAILED: Full overlap: %lld != 2\n", breaks);
+		fail = 1;
+	}
+
+	free(target);
+	close(break_fd);
+	return fail;
+}
+
 static int runtest(void)
 {
 	int rwflag;
@@ -172,7 +287,9 @@ static int runtest(void)
 				return ret;
 		}
 	}
-	return 0;
+
+	ret = runtest_dar_outside();
+	return ret;
 }