Disable 64-bit atomics for MIPS n32.

This patch disables use of 64-bit atomics for MIPS n32 to fix the
problems with unaligned semaphores.

Before 64-bit atomics are used for anything for which such alignment
issues do not arise, and before the addition of any new ILP32 ports
with 64-bit semaphores for which the ABI can be set to have the
greater alignment (AARCH64?), a better approach will need to be
established that allows architectures to declare their 64-bit atomics
availability accurately, without doing so causing inappropriate use of
such atomics on unaligned semaphores.

Tested for MIPS n32 that this fixes the nptl/tst-sem3 failure.

	* sysdeps/mips/bits/atomic.h [_MIPS_SIM == _ABIN32]
	(__HAVE_64B_ATOMICS): Define to 0.

diff --git a/ChangeLog b/ChangeLog
index 52f8c11..1a7d519 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2015-01-28  Joseph Myers  <joseph@codesourcery.com>
+
+       * sysdeps/mips/bits/atomic.h [_MIPS_SIM == _ABIN32]
+       (__HAVE_64B_ATOMICS): Define to 0.
+
 2015-01-28  Adhemerval Zanellla  <azanella@linux.vnet.ibm.com>
 
        [BZ #17885]

diff --git a/sysdeps/mips/bits/atomic.h b/sysdeps/mips/bits/atomic.h
index ddcb039..a391881 100644 (file)
--- a/sysdeps/mips/bits/atomic.h
+++ b/sysdeps/mips/bits/atomic.h
@@ -44,7 +44,7 @@ typedef uintmax_t uatomic_max_t;
 #define MIPS_PUSH_MIPS2
 #endif
 
-#if _MIPS_SIM == _ABIO32
+#if _MIPS_SIM == _ABIO32 || _MIPS_SIM == _ABIN32
 #define __HAVE_64B_ATOMICS 0
 #else
 #define __HAVE_64B_ATOMICS 1