1 files changed, 59 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/tst-rseq.h b/sysdeps/unix/sysv/linux/tst-rseq.h
new file mode 100644
index 0000000000..c2cb211f56
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-rseq.h
@@ -0,0 +1,59 @@
+/* Restartable Sequences tests header.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+
+   The GNU C 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; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C 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.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <error.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <support/check.h>
+#include <syscall.h>
+#include <sys/rseq.h>
+
+static inline bool
+rseq_thread_registered (void)
+{
+  int32_t v;
+
+  __atomic_load (&__rseq_abi.cpu_id, &v, __ATOMIC_RELAXED);
+  return v >= 0;
+}
+
+static inline int
+sys_rseq (struct rseq *rseq_abi, uint32_t rseq_len, int flags, uint32_t sig)
+{
+  return syscall (__NR_rseq, rseq_abi, rseq_len, flags, sig);
+}
+
+static inline bool
+rseq_available (void)
+{
+  int rc;
+
+  rc = sys_rseq (NULL, 0, 0, 0);
+  if (rc != -1)
+    FAIL_EXIT1 ("Unexpected rseq return value %d", rc);
+  switch (errno)
+    {
+    case ENOSYS:
+      return false;
+    case EINVAL:
+      /* rseq is implemented, but detected an invalid rseq_len parameter.  */
+      return true;
+    default:
+      FAIL_EXIT1 ("Unexpected rseq error %s", strerror (errno));
+    }
+}