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authorThomas Gleixner <tglx@linutronix.de>2008-02-16 14:05:01 +0100
committerIngo Molnar <mingo@elte.hu>2008-02-26 12:56:06 +0100
commitf18edc95a37a901ffcbe91f5e05105f916a04fae (patch)
tree66bb079a44a7bf997207cce8eb6b3c840082c45d
parent12c247a6719987aad65f83158d2bb3e73c75c1f5 (diff)
x86: no robust/pi futex for real i386 CPUs
Real i386 CPUs do not have cmpxchg instructions. Catch it before crashing on an invalid opcode. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r--include/asm-x86/futex.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/include/asm-x86/futex.h b/include/asm-x86/futex.h
index cd9f894dd2d..c9952ea9f69 100644
--- a/include/asm-x86/futex.h
+++ b/include/asm-x86/futex.h
@@ -102,6 +102,13 @@ futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
static inline int
futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
{
+
+#if defined(CONFIG_X86_32) && !defined(CONFIG_X86_BSWAP)
+ /* Real i386 machines have no cmpxchg instruction */
+ if (boot_cpu_data.x86 == 3)
+ return -ENOSYS;
+#endif
+
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
return -EFAULT;