Implement pthread_spinlock_* (Tim Potter, tpot@samba.org)

MERGE TO STABLE


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@1902 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/coregrind/arch/x86-linux/vg_libpthread.c b/coregrind/arch/x86-linux/vg_libpthread.c
index 0591fc0..0d8abca 100644
--- a/coregrind/arch/x86-linux/vg_libpthread.c
+++ b/coregrind/arch/x86-linux/vg_libpthread.c
@@ -3145,6 +3145,61 @@
 strong_alias(__pthread_mutexattr_settype, __pthread_mutexattr_setkind_np)
 weak_alias(__pthread_mutexattr_setkind_np, pthread_mutexattr_setkind_np)
 
+/* POSIX spinlocks, taken from glibc linuxthreads/sysdeps/i386 */
+
+typedef volatile int pthread_spinlock_t; /* Huh?  Guarded by __USE_XOPEN2K */
+
+int pthread_spin_init(pthread_spinlock_t *lock, int pshared)
+{
+  /* We can ignore the `pshared' parameter.  Since we are busy-waiting
+     all processes which can access the memory location `lock' points
+     to can use the spinlock.  */
+  *lock = 1;
+  return 0;
+}
+
+int pthread_spin_lock(pthread_spinlock_t *lock)
+{
+  asm volatile
+    ("\n"
+     "1:\n\t"
+     "lock; decl %0\n\t"
+     "js 2f\n\t"
+     ".section .text.spinlock,\"ax\"\n"
+     "2:\n\t"
+     "cmpl $0,%0\n\t"
+     "rep; nop\n\t"
+     "jle 2b\n\t"
+     "jmp 1b\n\t"
+     ".previous"
+     : "=m" (*lock));
+  return 0;
+}
+
+int pthread_spin_unlock(pthread_spinlock_t *lock)
+{
+  asm volatile
+    ("movl $1,%0"
+     : "=m" (*lock));
+  return 0;
+}
+
+int pthread_spin_destroy(pthread_spinlock_t *lock)
+{
+  /* Nothing to do.  */
+  return 0;
+}
+
+int pthread_spin_trylock(pthread_spinlock_t *lock)
+{
+  int oldval;
+
+  asm volatile
+    ("xchgl %0,%1"
+     : "=r" (oldval), "=m" (*lock)
+     : "0" (0));
+  return oldval > 0 ? 0 : EBUSY;
+}
 
 /*--------------------------------------------------------------------*/
 /*--- end                                          vg_libpthread.c ---*/
diff --git a/coregrind/arch/x86-linux/vg_libpthread_unimp.c b/coregrind/arch/x86-linux/vg_libpthread_unimp.c
index bac1778..92bed8c 100644
--- a/coregrind/arch/x86-linux/vg_libpthread_unimp.c
+++ b/coregrind/arch/x86-linux/vg_libpthread_unimp.c
@@ -255,16 +255,16 @@
 //                      { vgPlain_unimp("pthread_mutexattr_setpshared"); }
 //__attribute__((weak)) void pthread_setconcurrency ( void )
 //                      { vgPlain_unimp("pthread_setconcurrency"); }
-__attribute__((weak)) void pthread_spin_destroy ( void )
-                      { vgPlain_unimp("pthread_spin_destroy"); }
-__attribute__((weak)) void pthread_spin_init ( void )
-                      { vgPlain_unimp("pthread_spin_init"); }
-__attribute__((weak)) void pthread_spin_lock ( void )
-                      { vgPlain_unimp("pthread_spin_lock"); }
-__attribute__((weak)) void pthread_spin_trylock ( void )
-                      { vgPlain_unimp("pthread_spin_trylock"); }
-__attribute__((weak)) void pthread_spin_unlock ( void )
-                      { vgPlain_unimp("pthread_spin_unlock"); }
+//__attribute__((weak)) void pthread_spin_destroy ( void )
+//                      { vgPlain_unimp("pthread_spin_destroy"); }
+//__attribute__((weak)) void pthread_spin_init ( void )
+//                      { vgPlain_unimp("pthread_spin_init"); }
+//__attribute__((weak)) void pthread_spin_lock ( void )
+//                      { vgPlain_unimp("pthread_spin_lock"); }
+//__attribute__((weak)) void pthread_spin_trylock ( void )
+//                      { vgPlain_unimp("pthread_spin_trylock"); }
+//__attribute__((weak)) void pthread_spin_unlock ( void )
+//                      { vgPlain_unimp("pthread_spin_unlock"); }
 
 
 /*--------------------------------------------------------------------*/
diff --git a/coregrind/vg_libpthread.c b/coregrind/vg_libpthread.c
index 0591fc0..0d8abca 100644
--- a/coregrind/vg_libpthread.c
+++ b/coregrind/vg_libpthread.c
@@ -3145,6 +3145,61 @@
 strong_alias(__pthread_mutexattr_settype, __pthread_mutexattr_setkind_np)
 weak_alias(__pthread_mutexattr_setkind_np, pthread_mutexattr_setkind_np)
 
+/* POSIX spinlocks, taken from glibc linuxthreads/sysdeps/i386 */
+
+typedef volatile int pthread_spinlock_t; /* Huh?  Guarded by __USE_XOPEN2K */
+
+int pthread_spin_init(pthread_spinlock_t *lock, int pshared)
+{
+  /* We can ignore the `pshared' parameter.  Since we are busy-waiting
+     all processes which can access the memory location `lock' points
+     to can use the spinlock.  */
+  *lock = 1;
+  return 0;
+}
+
+int pthread_spin_lock(pthread_spinlock_t *lock)
+{
+  asm volatile
+    ("\n"
+     "1:\n\t"
+     "lock; decl %0\n\t"
+     "js 2f\n\t"
+     ".section .text.spinlock,\"ax\"\n"
+     "2:\n\t"
+     "cmpl $0,%0\n\t"
+     "rep; nop\n\t"
+     "jle 2b\n\t"
+     "jmp 1b\n\t"
+     ".previous"
+     : "=m" (*lock));
+  return 0;
+}
+
+int pthread_spin_unlock(pthread_spinlock_t *lock)
+{
+  asm volatile
+    ("movl $1,%0"
+     : "=m" (*lock));
+  return 0;
+}
+
+int pthread_spin_destroy(pthread_spinlock_t *lock)
+{
+  /* Nothing to do.  */
+  return 0;
+}
+
+int pthread_spin_trylock(pthread_spinlock_t *lock)
+{
+  int oldval;
+
+  asm volatile
+    ("xchgl %0,%1"
+     : "=r" (oldval), "=m" (*lock)
+     : "0" (0));
+  return oldval > 0 ? 0 : EBUSY;
+}
 
 /*--------------------------------------------------------------------*/
 /*--- end                                          vg_libpthread.c ---*/
diff --git a/coregrind/vg_libpthread_unimp.c b/coregrind/vg_libpthread_unimp.c
index bac1778..92bed8c 100644
--- a/coregrind/vg_libpthread_unimp.c
+++ b/coregrind/vg_libpthread_unimp.c
@@ -255,16 +255,16 @@
 //                      { vgPlain_unimp("pthread_mutexattr_setpshared"); }
 //__attribute__((weak)) void pthread_setconcurrency ( void )
 //                      { vgPlain_unimp("pthread_setconcurrency"); }
-__attribute__((weak)) void pthread_spin_destroy ( void )
-                      { vgPlain_unimp("pthread_spin_destroy"); }
-__attribute__((weak)) void pthread_spin_init ( void )
-                      { vgPlain_unimp("pthread_spin_init"); }
-__attribute__((weak)) void pthread_spin_lock ( void )
-                      { vgPlain_unimp("pthread_spin_lock"); }
-__attribute__((weak)) void pthread_spin_trylock ( void )
-                      { vgPlain_unimp("pthread_spin_trylock"); }
-__attribute__((weak)) void pthread_spin_unlock ( void )
-                      { vgPlain_unimp("pthread_spin_unlock"); }
+//__attribute__((weak)) void pthread_spin_destroy ( void )
+//                      { vgPlain_unimp("pthread_spin_destroy"); }
+//__attribute__((weak)) void pthread_spin_init ( void )
+//                      { vgPlain_unimp("pthread_spin_init"); }
+//__attribute__((weak)) void pthread_spin_lock ( void )
+//                      { vgPlain_unimp("pthread_spin_lock"); }
+//__attribute__((weak)) void pthread_spin_trylock ( void )
+//                      { vgPlain_unimp("pthread_spin_trylock"); }
+//__attribute__((weak)) void pthread_spin_unlock ( void )
+//                      { vgPlain_unimp("pthread_spin_unlock"); }
 
 
 /*--------------------------------------------------------------------*/