nptl: Add rseq registration

The rseq area is placed directly into struct pthread.  rseq
registration failure is not treated as an error, so it is possible
that threads run with inconsistent registration status.

<sys/rseq.h> is not yet installed as a public header.

Co-Authored-By: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/nptl/descr.h b/nptl/descr.h
index af2a6ab87a..92db305913 100644
--- a/nptl/descr.h
+++ b/nptl/descr.h
@@ -34,6 +34,7 @@
 #include <bits/types/res_state.h>
 #include <kernel-features.h>
 #include <tls-internal-struct.h>
+#include <sys/rseq.h>
 
 #ifndef TCB_ALIGNMENT
 # define TCB_ALIGNMENT 32
@@ -406,6 +407,9 @@ struct pthread
   /* Used on strsignal.  */
   struct tls_internal_t tls_state;
 
+  /* rseq area registered with the kernel.  */
+  struct rseq rseq_area;
+
   /* This member must be last.  */
   char end_padding[];