linux-kernel - [PATCH] selftests: breakpoints: check RTC wakeup alarm support before test

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Message-ID: <20251112061532.2867859-1-zhengxinyu6@huawei.com>
Date: Wed, 12 Nov 2025 06:15:32 +0000
From: Xinyu Zheng <zhengxinyu6@...wei.com>
To: Shuah Khan <shuah@...nel.org>
CC: Moon Hee Lee <moonhee.lee.ca@...il.com>, <yifei.l.liu@...cle.com>,
	<zhujun2@...s.chinamobile.com>, <linux-kselftest@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <zouyipeng@...wei.com>,
	<zhengxinyu6@...wei.com>
Subject: [PATCH] selftests: breakpoints: check RTC wakeup alarm support before test

If RTC wakeup alarm feature is unsupported, this testcase may cause
infinite suspend if there is no other wakeup source. To solve this
problem, set wakeup alarm up before we trigger suspend. In this case,
we can test if RTC support RTC_FEATURE_ALARM and efi_set_alarm function.

Signed-off-by: Xinyu Zheng <zhengxinyu6@...wei.com>
---
 .../breakpoints/step_after_suspend_test.c     | 23 +++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/tools/testing/selftests/breakpoints/step_after_suspend_test.c b/tools/testing/selftests/breakpoints/step_after_suspend_test.c
index 8d233ac95696..e738af896ce1 100644
--- a/tools/testing/selftests/breakpoints/step_after_suspend_test.c
+++ b/tools/testing/selftests/breakpoints/step_after_suspend_test.c
@@ -13,6 +13,8 @@
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
+#include <linux/rtc.h>
+#include <sys/ioctl.h>
 #include <sys/ptrace.h>
 #include <sys/stat.h>
 #include <sys/timerfd.h>
@@ -159,10 +161,30 @@ void suspend(void)
 	int count_before;
 	int count_after;
 	struct itimerspec spec = {};
+	char *rtc_file = "/dev/rtc0";
+	int rtc_fd;
+	struct rtc_wkalrm alarm = { 0 };
+	time_t secs;
 
 	if (getuid() != 0)
 		ksft_exit_skip("Please run the test as root - Exiting.\n");
 
+	rtc_fd = open(rtc_file, O_RDONLY);
+	if (rtc_fd < 0)
+		ksft_exit_fail_msg("open rtc0 failed\n");
+
+	err = ioctl(rtc_fd, RTC_RD_TIME, &alarm.time);
+	if (err < 0)
+		ksft_exit_fail_msg("get rtc time failed\n");
+
+	secs = timegm((struct tm *)&alarm.time) + 3;
+	gmtime_r(&secs, (struct tm *)&alarm.time);
+	alarm.enabled = 1;
+
+	err = ioctl(rtc_fd, RTC_WKALM_SET, &alarm);
+	if (err < 0)
+		ksft_exit_fail_msg("set wake alarm test failed, errno %d\n", errno);
+
 	timerfd = timerfd_create(CLOCK_BOOTTIME_ALARM, 0);
 	if (timerfd < 0)
 		ksft_exit_fail_msg("timerfd_create() failed\n");
@@ -180,6 +202,7 @@ void suspend(void)
 	if (count_after <= count_before)
 		ksft_exit_fail_msg("Failed to enter Suspend state\n");
 
+	close(rtc_fd);
 	close(timerfd);
 }
 
-- 
2.34.1