zdtm: membarrier: test migration of membarrier() registration

Signed-off-by: Michał Mirosław <[email protected]>
checkpoint-restore · Aug 2, 2023 · c41bc8a · c41bc8a
1 parent 87fbf58
commit c41bc8a
Show file tree

Hide file tree

Showing 2 changed files with 117 additions and 0 deletions.
diff --git a/test/zdtm/static/Makefile b/test/zdtm/static/Makefile
@@ -62,6 +62,7 @@ TST_NOFILE	:=				\
 		pthread_timers			\
 		pthread_timers_h		\
 		rseq00				\
+		membarrier			\
 		vdso00				\
 		vdso01				\
 		vdso02				\

diff --git a/test/zdtm/static/membarrier.c b/test/zdtm/static/membarrier.c
@@ -0,0 +1,116 @@
+#include <linux/membarrier.h>
+#include <sys/syscall.h>
+#include <stdbool.h>
+#include "zdtmtst.h"
+
+const char *test_doc = "Test membarrier() migration";
+const char *test_author = "Michał Mirosław <[email protected]>";
+
+/*
+ * Define membarrier() CMDs to avoid depending on exact kernel header version.
+ * FIXME: use MEMBARRIER_CMD_GET_REGISTRATIONS if supported by kernel.
+ */
+#define MEMBARRIER_CMD_PRIVATE_EXPEDITED                    (1 << 3)
+#define MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED           (1 << 4)
+#define MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE          (1 << 5)
+#define MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_SYNC_CORE (1 << 6)
+#define MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ               (1 << 7)
+#define MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_RSEQ      (1 << 8)
+
+static int membarrier(int cmd, unsigned int flags, int cpu_id)
+{
+	return syscall(__NR_membarrier, cmd, flags, cpu_id);
+}
+
+static const struct {
+	const char *name_suffix;
+	int register_cmd;
+	int execute_cmd;
+} membarrier_cmds[] = {
+	{ "",           MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED,           MEMBARRIER_CMD_PRIVATE_EXPEDITED },
+	{ "_SYNC_CORE", MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_SYNC_CORE, MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE },
+	{ "_RSEQ",      MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_RSEQ,      MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ },
+};
+static const int n_membarrier_cmds = sizeof(membarrier_cmds) / sizeof(*membarrier_cmds);
+
+static int register_membarriers(void)
+{
+	int barriers_supported, barriers_registered;
+	bool all_ok = true;
+
+	barriers_supported = membarrier(MEMBARRIER_CMD_QUERY, 0, 0);
+	if (barriers_supported < 0) {
+		fail("membarrier() not supported by running kernel");
+		return -1;
+	}
+
+	barriers_registered = 0;
+	for (int i = 0; i < n_membarrier_cmds; ++i) {
+		if (~barriers_supported & membarrier_cmds[i].register_cmd)
+			continue;
+
+		barriers_registered |= membarrier_cmds[i].execute_cmd;
+
+		if (membarrier(membarrier_cmds[i].register_cmd, 0, 0) < 0) {
+			pr_perror("membarrier(REGISTER_PRIVATE_EXPEDITED%s)", membarrier_cmds[i].name_suffix);
+			all_ok = false;
+		}
+	}
+
+	if (!all_ok) {
+		fail("can't register membarrier()s - tried %#x, kernel %#x",
+		     barriers_registered, barriers_supported);
+		return -1;
+	}
+
+	if (!barriers_registered) {
+		fail("no known membarrier() cmds are supported by the kernel");
+		return -1;
+	}
+
+	return barriers_registered;
+}
+
+static bool check_membarriers(int barriers_registered)
+{
+	bool all_ok = true;
+
+	for (int i = 0; i < n_membarrier_cmds; ++i) {
+		if (~barriers_registered & membarrier_cmds[i].execute_cmd)
+			continue;
+		if (membarrier(membarrier_cmds[i].execute_cmd, 0, 0) < 0) {
+			pr_perror("membarrier(PRIVATE_EXPEDITED%s)", membarrier_cmds[i].name_suffix);
+			all_ok = false;
+		}
+	}
+
+	if (!all_ok)
+		fail("membarrier() check failed");
+
+	return all_ok;
+}
+
+int main(int argc, char **argv)
+{
+	int barriers_registered;
+
+	test_init(argc, argv);
+
+	barriers_registered = register_membarriers();
+	if (barriers_registered < 0)
+		return 1;
+
+	test_msg("Pre-migration membarriers check\n");
+	if (!check_membarriers(barriers_registered))
+		return 1;
+
+	test_daemon();
+	test_waitsig();
+
+	test_msg("Post-migration membarriers check\n");
+	if (!check_membarriers(barriers_registered))
+		return 1;
+
+	pass();
+	return 0;
+}