Commit f18edc95 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
Browse files

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: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 12c247a6

include/asm-x86/futex.h

+7 −0
Original line number Diff line number Diff line
@@ -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;