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Commit bafe00cc authored by Martin Schwidefsky's avatar Martin Schwidefsky Committed by Linus Torvalds
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[PATCH] s390: fix in-user atomic futex operation. 



From: Martin Schwidefsky <schwidefsky@de.ibm.com>

__futex_atomic_op needs to do an atomic operation in the user address space,
not the kernel address space.  Add the missing sacf 256/sacf 0 to switch to
the secondary mode before doing the compare-and-swap.  In addition add
another fixup for catch specification exceptions if the compare-and-swap
address is not aligned.

Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 71601e2b

include/asm-s390/futex.h

+8 −7
Original line number Diff line number Diff line
@@ -11,23 +11,24 @@ 
#define __futex_atomic_fixup \

		     ".section __ex_table,\"a\"\n"			\

		     "   .align 4\n"					\

		     "   .long  0b,2b,1b,2b\n"				\

		     "   .long  0b,4b,2b,4b,3b,4b\n"			\

		     ".previous"

#else /* __s390x__ */

#define __futex_atomic_fixup \

		     ".section __ex_table,\"a\"\n"			\

		     "   .align 8\n"					\

		     "   .quad  0b,2b,1b,2b\n"				\

		     "   .quad  0b,4b,2b,4b,3b,4b\n"			\

		     ".previous"

#endif /* __s390x__ */



#define __futex_atomic_op(insn, ret, oldval, newval, uaddr, oparg)	\

	asm volatile("   l   %1,0(%6)\n"				\

		     "0: " insn						\

		     "   cs  %1,%2,0(%6)\n"				\

		     "1: jl  0b\n"					\

	asm volatile("   sacf 256\n"					\

		     "0: l   %1,0(%6)\n"				\

		     "1: " insn						\

		     "2: cs  %1,%2,0(%6)\n"				\

		     "3: jl  1b\n"					\

		     "   lhi %0,0\n"					\

		     "2:\n"						\

		     "4: sacf 0\n"					\

		     __futex_atomic_fixup				\

		     : "=d" (ret), "=&d" (oldval), "=&d" (newval),	\

		       "=m" (*uaddr)					\