[PATCH] PPC64 Linuxthread pspinlock uses 64-bits when it should not.

[Steve Munroe <sjmunroe at us dot ibm dot com>]

Thanks to Marcuc Meissner for finding this one.

The powerpc64 implemention of spinlock uses __compare_and_swap from 
sysdeps/powerpc/powerpc64/pt-machine (which used 64-bit load and 
reserve/store conditional) but pthread_spinlock_t is defined as int.

The following patch fixes this.
2004-02-20  Steven Munroe  <sjmunroe@us.ibm.com>

	* sysdeps/powerpc/pspinlock.c: Move from here.
	* sysdeps/powerpc/powerpc32/pspinlock.c: To here.
	* sysdeps/powerpc/powerpc64/pspinlock.c: New file.
	* sysdeps/powerpc/powerpc64/pt-machine.h: Define __compare_and_swap32
	and __compare_and_swap32_with_release_semantics

diff -urN libc23-cvstip-20040218/linuxthreads/sysdeps/powerpc/powerpc32/pspinlock.c libc23/linuxthreads/sysdeps/powerpc/powerpc32/pspinlock.c
--- libc23-cvstip-20040218/linuxthreads/sysdeps/powerpc/powerpc32/pspinlock.c	Wed Dec 31 17:00:00 1969
+++ libc23/linuxthreads/sysdeps/powerpc/powerpc32/pspinlock.c	Fri Feb 20 10:47:39 2004
@@ -0,0 +1,70 @@
+/* POSIX spinlock implementation.  PowerPC version.
+   Copyright (C) 2000, 2003 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <errno.h>
+#include <pthread.h>
+#include "internals.h"
+
+int
+__pthread_spin_lock (pthread_spinlock_t *lock)
+{
+  while (! __compare_and_swap ((long int *)lock, 0, 1))
+    ;
+  return 0;
+}
+weak_alias (__pthread_spin_lock, pthread_spin_lock)
+
+
+int
+__pthread_spin_trylock (pthread_spinlock_t *lock)
+{
+  return __compare_and_swap ((long int *)lock, 0, 1) ? 0 : EBUSY;
+}
+weak_alias (__pthread_spin_trylock, pthread_spin_trylock)
+
+
+int
+__pthread_spin_unlock (pthread_spinlock_t *lock)
+{
+  MEMORY_BARRIER ();
+  *lock = 0;
+  return 0;
+}
+weak_alias (__pthread_spin_unlock, pthread_spin_unlock)
+
+
+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 = 0;
+  return 0;
+}
+weak_alias (__pthread_spin_init, pthread_spin_init)
+
+
+int
+__pthread_spin_destroy (pthread_spinlock_t *lock)
+{
+  /* Nothing to do.  */
+  return 0;
+}
+weak_alias (__pthread_spin_destroy, pthread_spin_destroy)
diff -urN libc23-cvstip-20040218/linuxthreads/sysdeps/powerpc/powerpc64/pspinlock.c libc23/linuxthreads/sysdeps/powerpc/powerpc64/pspinlock.c
--- libc23-cvstip-20040218/linuxthreads/sysdeps/powerpc/powerpc64/pspinlock.c	Wed Dec 31 17:00:00 1969
+++ libc23/linuxthreads/sysdeps/powerpc/powerpc64/pspinlock.c	Fri Feb 20 10:58:35 2004
@@ -0,0 +1,70 @@
+/* POSIX spinlock implementation.  PowerPC version.
+   Copyright (C) 2000, 2003 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <errno.h>
+#include <pthread.h>
+#include "internals.h"
+
+int
+__pthread_spin_lock (pthread_spinlock_t *lock)
+{
+  while (! __compare_and_swap32 ((int *)lock, 0, 1))
+    ;
+  return 0;
+}
+weak_alias (__pthread_spin_lock, pthread_spin_lock)
+
+
+int
+__pthread_spin_trylock (pthread_spinlock_t *lock)
+{
+  return __compare_and_swap32 ((int *)lock, 0, 1) ? 0 : EBUSY;
+}
+weak_alias (__pthread_spin_trylock, pthread_spin_trylock)
+
+
+int
+__pthread_spin_unlock (pthread_spinlock_t *lock)
+{
+  MEMORY_BARRIER ();
+  *lock = 0;
+  return 0;
+}
+weak_alias (__pthread_spin_unlock, pthread_spin_unlock)
+
+
+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 = 0;
+  return 0;
+}
+weak_alias (__pthread_spin_init, pthread_spin_init)
+
+
+int
+__pthread_spin_destroy (pthread_spinlock_t *lock)
+{
+  /* Nothing to do.  */
+  return 0;
+}
+weak_alias (__pthread_spin_destroy, pthread_spin_destroy)
diff -urN libc23-cvstip-20040218/linuxthreads/sysdeps/powerpc/powerpc64/pt-machine.h libc23/linuxthreads/sysdeps/powerpc/powerpc64/pt-machine.h
--- libc23-cvstip-20040218/linuxthreads/sysdeps/powerpc/powerpc64/pt-machine.h	2003-09-11 13:47:55.000000000 -0500
+++ libc23/linuxthreads/sysdeps/powerpc/powerpc64/pt-machine.h	2004-02-20 10:43:55.000000000 -0600
@@ -30,6 +30,7 @@
 
 extern long int testandset (int *spinlock);
 extern int __compare_and_swap (long int *p, long int oldval, long int newval);
+extern int __compare_and_swap32 (int *p, int oldval, int newval);
 
 /* For multiprocessor systems, we want to ensure all memory accesses
    are completed before we reset a lock.  On other systems, we still
@@ -118,6 +119,49 @@
   return (int)(ret == 0);
 }
 
+PT_EI int
+__compare_and_swap32 (int *p, int oldval, int newval)
+{
+  int ret;
+
+  __asm__ __volatile__ (
+	   "0:    lwarx %0,0,%1 ;"
+	   "      xor. %0,%3,%0;"
+	   "      bne 1f;"
+	   "      stwcx. %2,0,%1;"
+	   "      bne- 0b;"
+	   "1:    "
+	: "=&r"(ret)
+	: "r"(p), "r"(newval), "r"(oldval)
+	: "cr0", "memory");
+  /* This version of __compare_and_swap is to be used when acquiring
+     a lock, so we don't need to worry about whether other memory
+     operations have completed, but we do need to be sure that any loads
+     after this point really occur after we have acquired the lock.  */
+  __asm__ __volatile__ ("isync" : : : "memory");
+  return (int)(ret == 0);
+}
+
+PT_EI int
+__compare_and_swap32_with_release_semantics (long int *p,
+					   long int oldval, long int newval)
+{
+  long int ret;
+
+  MEMORY_BARRIER ();
+  __asm__ __volatile__ (
+	   "0:    lwarx %0,0,%1 ;"
+	   "      xor. %0,%3,%0;"
+	   "      bne 1f;"
+	   "      stwcx. %2,0,%1;"
+	   "      bne- 0b;"
+	   "1:    "
+	: "=&r"(ret)
+	: "r"(p), "r"(newval), "r"(oldval)
+	: "cr0", "memory");
+  return (int)(ret == 0);
+}
+
 PT_EI long int
 testandset (int *p)
 {
diff -urN libc23-cvstip-20040218/linuxthreads/sysdeps/powerpc/pspinlock.c libc23/linuxthreads/sysdeps/powerpc/pspinlock.c
--- libc23-cvstip-20040218/linuxthreads/sysdeps/powerpc/pspinlock.c	Wed Jun 11 18:21:56 2003
+++ libc23/linuxthreads/sysdeps/powerpc/pspinlock.c	Wed Dec 31 17:00:00 1969
@@ -1,70 +0,0 @@
-/* POSIX spinlock implementation.  PowerPC version.
-   Copyright (C) 2000, 2003 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public License as
-   published by the Free Software Foundation; either version 2.1 of the
-   License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; see the file COPYING.LIB.  If not,
-   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-   Boston, MA 02111-1307, USA.  */
-
-#include <errno.h>
-#include <pthread.h>
-#include "internals.h"
-
-int
-__pthread_spin_lock (pthread_spinlock_t *lock)
-{
-  while (! __compare_and_swap ((long int *)lock, 0, 1))
-    ;
-  return 0;
-}
-weak_alias (__pthread_spin_lock, pthread_spin_lock)
-
-
-int
-__pthread_spin_trylock (pthread_spinlock_t *lock)
-{
-  return __compare_and_swap ((long int *)lock, 0, 1) ? 0 : EBUSY;
-}
-weak_alias (__pthread_spin_trylock, pthread_spin_trylock)
-
-
-int
-__pthread_spin_unlock (pthread_spinlock_t *lock)
-{
-  MEMORY_BARRIER ();
-  *lock = 0;
-  return 0;
-}
-weak_alias (__pthread_spin_unlock, pthread_spin_unlock)
-
-
-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 = 0;
-  return 0;
-}
-weak_alias (__pthread_spin_init, pthread_spin_init)
-
-
-int
-__pthread_spin_destroy (pthread_spinlock_t *lock)
-{
-  /* Nothing to do.  */
-  return 0;
-}
-weak_alias (__pthread_spin_destroy, pthread_spin_destroy)