# 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.

# 

diff -urN glibc-2.17-c758a686/nptl/sysdeps/powerpc/tls.h glibc-2.17-c758a686/nptl/sysdeps/powerpc/tls.h

--- glibc-2.17-c758a686/nptl/sysdeps/powerpc/tls.h	2014-05-29 13:19:25.000000000 -0500

+++ glibc-2.17-c758a686/nptl/sysdeps/powerpc/tls.h	2014-05-29 13:19:25.000000000 -0500

@@ -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;