# commit b525166bb93b060e1146f0263b76a9c1e7455b06
# Author: Ulrich Weigand <Ulrich.Weigand@de.ibm.com>
# Date:   Wed Dec 4 06:45:56 2013 -0600
# 
#     PowerPC64: Add __private_ss field to TCB header
#     
#     The TCB header on Intel contains a field __private_ss that is used
#     to efficiently implement the -fsplit-stack GCC feature.
#     
#     In order to prepare for a possible future implementation of that
#     feature on powerpc64, we'd like to reserve a similar field in
#     the TCB header as well.  (It would be good if this went in with
#     or before the ELFv2 patches to ensure that this field will be
#     available always in the ELFv2 environment.)
#     
#     The field needs to be added at the front of tcbhead_t structure
#     to avoid changing the ABI; see the recent discussion when adding
#     the EBB fields.
# 
---
# nptl/sysdeps/powerpc/tls.h |    2 ++
# 1 file changed, 2 insertions(+)
#
--- a/nptl/sysdeps/powerpc/tls.h
+++ b/nptl/sysdeps/powerpc/tls.h
@@ -61,6 +61,8 @@
    are private.  */
 typedef struct
 {
+  /* GCC split stack support.  */
+  void *__private_ss;
   /* Reservation for the Event-Based Branching ABI.  */
   uintptr_t ebb_handler;
   uintptr_t ebb_ctx_pointer;
