zdtm: add basic static/rseq00 test for rseq C/R

Here we just want to check that if rseq was registered before C/R
it remains registered after it.

Signed-off-by: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com>

test/zdtm/static/Makefile

@@ -61,6 +61,7 @@ TST_NOFILE	:=				\
 		pthread02			\
 		pthread_timers			\
 		pthread_timers_h		\
+		rseq00				\
 		vdso00				\
 		vdso01				\
 		vdso02				\

test/zdtm/static/rseq00.c

@@ -0,0 +1,110 @@
+/*
+ * test for rseq() syscall
+ * See also https://www.efficios.com/blog/2019/02/08/linux-restartable-sequences/
+ * https://github.com/torvalds/linux/commit/d7822b1e24f2df5df98c76f0e94a5416349ff759
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <signal.h>
+#include <string.h>
+
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <syscall.h>
+
+#include "zdtmtst.h"
+
+#if defined(__x86_64__)
+
+const char *test_doc = "Check that rseq() basic C/R works";
+const char *test_author = "Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com>";
+
+/* some useful definitions from kernel uapi */
+enum rseq_flags {
+	RSEQ_FLAG_UNREGISTER = (1 << 0),
+};
+
+struct rseq {
+	uint32_t cpu_id_start;
+	uint32_t cpu_id;
+	uint64_t rseq_cs;
+	uint32_t flags;
+} __attribute__((aligned(4 * sizeof(uint64_t))));
+
+#ifndef __NR_rseq
+#define __NR_rseq 334
+#endif
+/* EOF */
+
+static __thread volatile struct rseq __rseq_abi;
+
+#define RSEQ_SIG 0x53053053
+
+static int sys_rseq(volatile struct rseq *rseq_abi, uint32_t rseq_len, int flags, uint32_t sig)
+{
+	return syscall(__NR_rseq, rseq_abi, rseq_len, flags, sig);
+}
+
+static void register_thread(void)
+{
+	int rc;
+	rc = sys_rseq(&__rseq_abi, sizeof(struct rseq), 0, RSEQ_SIG);
+	if (rc) {
+		fail("Failed to register rseq");
+		exit(1);
+	}
+}
+
+static void unregister_thread(void)
+{
+	int rc;
+	rc = sys_rseq(&__rseq_abi, sizeof(struct rseq), RSEQ_FLAG_UNREGISTER, RSEQ_SIG);
+	if (rc) {
+		fail("Failed to unregister rseq");
+		exit(1);
+	}
+}
+
+static void check_thread(void)
+{
+	int rc;
+	rc = sys_rseq(&__rseq_abi, sizeof(struct rseq), 0, RSEQ_SIG);
+	if (!(rc && errno == EBUSY)) {
+		fail("Failed to check rseq %d", rc);
+		exit(1);
+	}
+}
+
+int main(int argc, char *argv[])
+{
+	test_init(argc, argv);
+
+	register_thread();
+
+	test_daemon();
+	test_waitsig();
+
+	check_thread();
+
+	pass();
+	return 0;
+}
+
+#else /* #if defined(__x86_64__) */
+
+int main(int argc, char *argv[])
+{
+	test_init(argc, argv);
+	skip("Unsupported arch");
+	test_daemon();
+	test_waitsig();
+	pass();
+	return 0;
+}
+
+#endif /* #if defined(__x86_64__) */

test/zdtm/static/rseq00.desc

@@ -0,0 +1 @@
+{'flavor': 'h', 'arch': 'x86_64', 'feature': 'get_rseq_conf'}