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sparc64: FUTEX_OP_ANDN fix
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Correct sparc64's implementation of FUTEX_OP_ANDN to do a
bitwise negate of the oparg parameter before applying the
AND operation. All other archs that support FUTEX_OP_ANDN
either negate oparg explicitly (frv, ia64, mips, sh, x86),
or do so indirectly by using an and-not instruction (powerpc).
Since sparc64 has and-not, I chose to use that solution.

I've not found any use of FUTEX_OP_ANDN in glibc so the
impact of this bug is probably minor. But other user-space
components may try to use it so it should still get fixed.

Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Mikael Pettersson authored and David S. Miller committed Jul 30, 2008
1 parent 19fd3ca commit d72609e
Showing 1 changed file with 1 addition and 1 deletion.
2 changes: 1 addition & 1 deletion arch/sparc/include/asm/futex_64.h
Original file line number Diff line number Diff line change
Expand Up @@ -59,7 +59,7 @@ static inline int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
__futex_cas_op("or\t%2, %4, %1", ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_ANDN:
__futex_cas_op("and\t%2, %4, %1", ret, oldval, uaddr, oparg);
__futex_cas_op("andn\t%2, %4, %1", ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_XOR:
__futex_cas_op("xor\t%2, %4, %1", ret, oldval, uaddr, oparg);
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