[newlib-cygwin] Self-contained pthread_spinlock_t for RTEMS

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=724e21493ab48794336f3d97152aeaa1fe3adbee

commit 724e21493ab48794336f3d97152aeaa1fe3adbee
Author: Sebastian Huber <sebastian.huber@embedded-brains.de>
Date:   Thu Nov 24 10:58:35 2016 +0100

    Self-contained pthread_spinlock_t for RTEMS
    
    Turn pthread_spinlock_t into a self-contained object.  On uni-processor
    configurations, interrupts are disabled in the lock/trylock operations
    and the previous interrupt status is restored in the corresponding
    unlock operations.  On SMP configurations, a ticket lock is a acquired
    and released in addition.
    
    See also:
    
    https://devel.rtems.org/ticket/2674
    
    This implementation is simple and efficient.  However, this test case of
    the Linux Test Project would fail due to call of printf() and sleep()
    during spin lock ownership:
    
    https://github.com/linux-test-project/ltp/blob/master/testcases/open_posix_testsuite/conformance/interfaces/pthread_spin_lock/1-2.c
    
    Signed-off-by: Sebastian Huber <sebastian.huber@embedded-brains.de>

Diff:
---
 newlib/libc/sys/rtems/include/sys/_pthreadtypes.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/newlib/libc/sys/rtems/include/sys/_pthreadtypes.h b/newlib/libc/sys/rtems/include/sys/_pthreadtypes.h
index e1a88e9..bd66c68 100644
--- a/newlib/libc/sys/rtems/include/sys/_pthreadtypes.h
+++ b/newlib/libc/sys/rtems/include/sys/_pthreadtypes.h
@@ -22,6 +22,7 @@
 
 #include <sys/sched.h>
 #include <sys/cpuset.h>
+#include <sys/lock.h>
 
 /*
  *  2.5 Primitive System Data Types,  P1003.1c/D10, p. 19.
@@ -190,7 +191,10 @@ typedef struct {
 /* POSIX Spin Lock Types */
 
 #if defined(_POSIX_SPIN_LOCKS)
-typedef __uint32_t pthread_spinlock_t;        /* POSIX Spin Lock Object */
+typedef struct {
+  struct _Ticket_lock_Control _Lock;
+  __uint32_t                  _interrupt_state;
+} pthread_spinlock_t;                        /* POSIX Spin Lock Object */
 #endif /* defined(_POSIX_SPIN_LOCKS) */
 
 /* POSIX Reader/Writer Lock Types */