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x86: no robust/pi futex for real i386 CPUs

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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>
This commit is contained in:
Thomas Gleixner 2008-02-16 14:05:01 +01:00 committed by Ingo Molnar
parent 12c247a671
commit f18edc95a3
1 changed files with 7 additions and 0 deletions
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7
include/asm-x86/futex.h
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@ -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;