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Commit 3363fbdd authored by Martin Schwidefsky's avatar Martin Schwidefsky Committed by Linus Torvalds
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[PATCH] s390: futex atomic operations 



Add support for atomic futex operations.

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 40ac6b20

include/asm-s390/futex.h

+119 −4
Original line number Original line Diff line number Diff line 
#ifndef _ASM_FUTEX_H

#ifndef _ASM_S390_FUTEX_H

#define _ASM_FUTEX_H

#define _ASM_S390_FUTEX_H





#include <asm-generic/futex.h>

#ifdef __KERNEL__





#endif
 
#include <linux/futex.h>

#include <asm/errno.h>

#include <asm/uaccess.h>



#ifndef __s390x__

#define __futex_atomic_fixup \

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

		     "   .align 4\n"					\

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

		     ".previous"

#else /* __s390x__ */

#define __futex_atomic_fixup \

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

		     "   .align 8\n"					\

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

		     "   lhi %0,0\n"					\

		     "2:\n"						\

		     __futex_atomic_fixup				\

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

		       "=m" (*uaddr)					\

		     : "0" (-EFAULT), "d" (oparg), "a" (uaddr),		\

		       "m" (*uaddr) : "cc" );



static inline int futex_atomic_op_inuser (int encoded_op, int __user *uaddr)

{

	int op = (encoded_op >> 28) & 7;

	int cmp = (encoded_op >> 24) & 15;

	int oparg = (encoded_op << 8) >> 20;

	int cmparg = (encoded_op << 20) >> 20;

	int oldval = 0, newval, ret;

	if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))

		oparg = 1 << oparg;



	if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))

		return -EFAULT;



	inc_preempt_count();



	switch (op) {

	case FUTEX_OP_SET:

		__futex_atomic_op("lr %2,%5\n",

				  ret, oldval, newval, uaddr, oparg);

		break;

	case FUTEX_OP_ADD:

		__futex_atomic_op("lr %2,%1\nar %2,%5\n",

				  ret, oldval, newval, uaddr, oparg);

		break;

	case FUTEX_OP_OR:

		__futex_atomic_op("lr %2,%1\nor %2,%5\n",

				  ret, oldval, newval, uaddr, oparg);

		break;

	case FUTEX_OP_ANDN:

		__futex_atomic_op("lr %2,%1\nnr %2,%5\n",

				  ret, oldval, newval, uaddr, oparg);

		break;

	case FUTEX_OP_XOR:

		__futex_atomic_op("lr %2,%1\nxr %2,%5\n",

				  ret, oldval, newval, uaddr, oparg);

		break;

	default:

		ret = -ENOSYS;

	}



	dec_preempt_count();



	if (!ret) {

		switch (cmp) {

		case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;

		case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;

		case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;

		case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;

		case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;

		case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;

		default: ret = -ENOSYS;

		}

	}

	return ret;

}



static inline int

futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)

{

	int ret;



	if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))

		return -EFAULT;

	asm volatile("   cs   %1,%4,0(%5)\n"

		     "0: lr   %0,%1\n"

		     "1:\n"

#ifndef __s390x__

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

		     "   .align 4\n"

		     "   .long  0b,1b\n"

		     ".previous"

#else /* __s390x__ */

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

		     "   .align 8\n"

		     "   .quad  0b,1b\n"

		     ".previous"

#endif /* __s390x__ */

		     : "=d" (ret), "+d" (oldval), "=m" (*uaddr)

		     : "0" (-EFAULT), "d" (newval), "a" (uaddr), "m" (*uaddr)

		     : "cc", "memory" );

	return oldval;

}



#endif /* __KERNEL__ */

#endif /* _ASM_S390_FUTEX_H */