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Commit ca5762c5 authored by Jan Beulich's avatar Jan Beulich Committed by Greg Kroah-Hartman
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x86: drop bogus "cc" clobber from __try_cmpxchg_user_asm() 



commit 1df931d95f4dc1c11db1123e85d4e08156e46ef9 upstream.

As noted (and fixed) a couple of times in the past, "=@cc<cond>" outputs
and clobbering of "cc" don't work well together. The compiler appears to
mean to reject such, but doesn't - in its upstream form - quite manage
to yet for "cc". Furthermore two similar macros don't clobber "cc", and
clobbering "cc" is pointless in asm()-s for x86 anyway - the compiler
always assumes status flags to be clobbered there.

Fixes: 989b5db215a2 ("x86/uaccess: Implement macros for CMPXCHG on user addresses")
Signed-off-by: default avatarJan Beulich <jbeulich@suse.com>
Message-Id: <485c0c0b-a3a7-0b7c-5264-7d00c01de032@suse.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent f88d8c18

arch/x86/include/asm/uaccess.h

+1 −1
Original line number Diff line number Diff line
@@ -498,7 +498,7 @@ __pu_label: \ 
		       [ptr] "+m" (*_ptr),				\

		       [old] "+a" (__old)				\

		     : [new] ltype (__new)				\

		     : "memory", "cc");					\

		     : "memory");					\

	if (unlikely(__err))						\

		goto label;						\

	if (unlikely(!success))						\