Project import generated by Copybara.
GitOrigin-RevId: bd0ddc2827eee24b618befa82c57ed4d577197d1
diff --git a/tools/testing/selftests/rseq/rseq.c b/tools/testing/selftests/rseq/rseq.c
new file mode 100644
index 0000000..986b945
--- /dev/null
+++ b/tools/testing/selftests/rseq/rseq.c
@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ * rseq.c
+ *
+ * Copyright (C) 2016 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; only
+ * version 2.1 of the License.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ */
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <sched.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <syscall.h>
+#include <assert.h>
+#include <signal.h>
+#include <limits.h>
+#include <dlfcn.h>
+#include <stddef.h>
+
+#include "../kselftest.h"
+#include "rseq.h"
+
+static const ptrdiff_t *libc_rseq_offset_p;
+static const unsigned int *libc_rseq_size_p;
+static const unsigned int *libc_rseq_flags_p;
+
+/* Offset from the thread pointer to the rseq area. */
+ptrdiff_t rseq_offset;
+
+/* Size of the registered rseq area. 0 if the registration was
+ unsuccessful. */
+unsigned int rseq_size = -1U;
+
+/* Flags used during rseq registration. */
+unsigned int rseq_flags;
+
+static int rseq_ownership;
+
+static
+__thread struct rseq_abi __rseq_abi __attribute__((tls_model("initial-exec"))) = {
+ .cpu_id = RSEQ_ABI_CPU_ID_UNINITIALIZED,
+};
+
+static int sys_rseq(struct rseq_abi *rseq_abi, uint32_t rseq_len,
+ int flags, uint32_t sig)
+{
+ return syscall(__NR_rseq, rseq_abi, rseq_len, flags, sig);
+}
+
+int rseq_available(void)
+{
+ int rc;
+
+ rc = sys_rseq(NULL, 0, 0, 0);
+ if (rc != -1)
+ abort();
+ switch (errno) {
+ case ENOSYS:
+ return 0;
+ case EINVAL:
+ return 1;
+ default:
+ abort();
+ }
+}
+
+int rseq_register_current_thread(void)
+{
+ int rc;
+
+ if (!rseq_ownership) {
+ /* Treat libc's ownership as a successful registration. */
+ return 0;
+ }
+ rc = sys_rseq(&__rseq_abi, sizeof(struct rseq_abi), 0, RSEQ_SIG);
+ if (rc)
+ return -1;
+ assert(rseq_current_cpu_raw() >= 0);
+ return 0;
+}
+
+int rseq_unregister_current_thread(void)
+{
+ int rc;
+
+ if (!rseq_ownership) {
+ /* Treat libc's ownership as a successful unregistration. */
+ return 0;
+ }
+ rc = sys_rseq(&__rseq_abi, sizeof(struct rseq_abi), RSEQ_ABI_FLAG_UNREGISTER, RSEQ_SIG);
+ if (rc)
+ return -1;
+ return 0;
+}
+
+static __attribute__((constructor))
+void rseq_init(void)
+{
+ libc_rseq_offset_p = dlsym(RTLD_NEXT, "__rseq_offset");
+ libc_rseq_size_p = dlsym(RTLD_NEXT, "__rseq_size");
+ libc_rseq_flags_p = dlsym(RTLD_NEXT, "__rseq_flags");
+ if (libc_rseq_size_p && libc_rseq_offset_p && libc_rseq_flags_p) {
+ /* rseq registration owned by glibc */
+ rseq_offset = *libc_rseq_offset_p;
+ rseq_size = *libc_rseq_size_p;
+ rseq_flags = *libc_rseq_flags_p;
+ return;
+ }
+ if (!rseq_available())
+ return;
+ rseq_ownership = 1;
+ rseq_offset = (void *)&__rseq_abi - rseq_thread_pointer();
+ rseq_size = sizeof(struct rseq_abi);
+ rseq_flags = 0;
+}
+
+static __attribute__((destructor))
+void rseq_exit(void)
+{
+ if (!rseq_ownership)
+ return;
+ rseq_offset = 0;
+ rseq_size = -1U;
+ rseq_ownership = 0;
+}
+
+int32_t rseq_fallback_current_cpu(void)
+{
+ int32_t cpu;
+
+ cpu = sched_getcpu();
+ if (cpu < 0) {
+ perror("sched_getcpu()");
+ abort();
+ }
+ return cpu;
+}
