File-copy from v4.4.100
This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Please refer to that tree for all history prior to this point.
Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/tools/testing/selftests/timers/clocksource-switch.c b/tools/testing/selftests/timers/clocksource-switch.c
new file mode 100644
index 0000000..627ec74
--- /dev/null
+++ b/tools/testing/selftests/timers/clocksource-switch.c
@@ -0,0 +1,179 @@
+/* Clocksource change test
+ * by: john stultz (johnstul@us.ibm.com)
+ * (C) Copyright IBM 2012
+ * Licensed under the GPLv2
+ *
+ * NOTE: This is a meta-test which quickly changes the clocksourc and
+ * then uses other tests to detect problems. Thus this test requires
+ * that the inconsistency-check and nanosleep tests be present in the
+ * same directory it is run from.
+ *
+ * To build:
+ * $ gcc clocksource-switch.c -o clocksource-switch -lrt
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <sys/time.h>
+#include <sys/timex.h>
+#include <time.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/wait.h>
+#ifdef KTEST
+#include "../kselftest.h"
+#else
+static inline int ksft_exit_pass(void)
+{
+ exit(0);
+}
+static inline int ksft_exit_fail(void)
+{
+ exit(1);
+}
+#endif
+
+
+int get_clocksources(char list[][30])
+{
+ int fd, i;
+ size_t size;
+ char buf[512];
+ char *head, *tmp;
+
+ fd = open("/sys/devices/system/clocksource/clocksource0/available_clocksource", O_RDONLY);
+
+ size = read(fd, buf, 512);
+
+ close(fd);
+
+ for (i = 0; i < 30; i++)
+ list[i][0] = '\0';
+
+ head = buf;
+ i = 0;
+ while (head - buf < size) {
+ /* Find the next space */
+ for (tmp = head; *tmp != ' '; tmp++) {
+ if (*tmp == '\n')
+ break;
+ if (*tmp == '\0')
+ break;
+ }
+ *tmp = '\0';
+ strcpy(list[i], head);
+ head = tmp + 1;
+ i++;
+ }
+
+ return i-1;
+}
+
+int get_cur_clocksource(char *buf, size_t size)
+{
+ int fd;
+
+ fd = open("/sys/devices/system/clocksource/clocksource0/current_clocksource", O_RDONLY);
+
+ size = read(fd, buf, size);
+
+ return 0;
+}
+
+int change_clocksource(char *clocksource)
+{
+ int fd;
+ size_t size;
+
+ fd = open("/sys/devices/system/clocksource/clocksource0/current_clocksource", O_WRONLY);
+
+ if (fd < 0)
+ return -1;
+
+ size = write(fd, clocksource, strlen(clocksource));
+
+ if (size < 0)
+ return -1;
+
+ close(fd);
+ return 0;
+}
+
+
+int run_tests(int secs)
+{
+ int ret;
+ char buf[255];
+
+ sprintf(buf, "./inconsistency-check -t %i", secs);
+ ret = system(buf);
+ if (ret)
+ return ret;
+ ret = system("./nanosleep");
+ return ret;
+}
+
+
+char clocksource_list[10][30];
+
+int main(int argv, char **argc)
+{
+ char orig_clk[512];
+ int count, i, status;
+ pid_t pid;
+
+ get_cur_clocksource(orig_clk, 512);
+
+ count = get_clocksources(clocksource_list);
+
+ if (change_clocksource(clocksource_list[0])) {
+ printf("Error: You probably need to run this as root\n");
+ return -1;
+ }
+
+ /* Check everything is sane before we start switching asyncrhonously */
+ for (i = 0; i < count; i++) {
+ printf("Validating clocksource %s\n", clocksource_list[i]);
+ if (change_clocksource(clocksource_list[i])) {
+ status = -1;
+ goto out;
+ }
+ if (run_tests(5)) {
+ status = -1;
+ goto out;
+ }
+ }
+
+
+ printf("Running Asyncrhonous Switching Tests...\n");
+ pid = fork();
+ if (!pid)
+ return run_tests(60);
+
+ while (pid != waitpid(pid, &status, WNOHANG))
+ for (i = 0; i < count; i++)
+ if (change_clocksource(clocksource_list[i])) {
+ status = -1;
+ goto out;
+ }
+out:
+ change_clocksource(orig_clk);
+
+ if (status)
+ return ksft_exit_fail();
+ return ksft_exit_pass();
+}