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243 lines
6.6 KiB
C
243 lines
6.6 KiB
C
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/* futex.c: futex operations
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*
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* Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/futex.h>
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#include <asm/futex.h>
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#include <asm/errno.h>
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#include <asm/uaccess.h>
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/*
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* the various futex operations; MMU fault checking is ignored under no-MMU
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* conditions
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*/
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static inline int atomic_futex_op_xchg_set(int oparg, int __user *uaddr, int *_oldval)
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{
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int oldval, ret;
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asm("0: \n"
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" orcc gr0,gr0,gr0,icc3 \n" /* set ICC3.Z */
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" ckeq icc3,cc7 \n"
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"1: ld.p %M0,%1 \n" /* LD.P/ORCR must be atomic */
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" orcr cc7,cc7,cc3 \n" /* set CC3 to true */
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"2: cst.p %3,%M0 ,cc3,#1 \n"
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" corcc gr29,gr29,gr0 ,cc3,#1 \n" /* clear ICC3.Z if store happens */
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" beq icc3,#0,0b \n"
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" setlos 0,%2 \n"
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"3: \n"
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".subsection 2 \n"
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"4: setlos %5,%2 \n"
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" bra 3b \n"
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".previous \n"
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".section __ex_table,\"a\" \n"
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" .balign 8 \n"
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" .long 1b,4b \n"
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" .long 2b,4b \n"
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".previous"
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: "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
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: "3"(oparg), "i"(-EFAULT)
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: "memory", "cc7", "cc3", "icc3"
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);
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*_oldval = oldval;
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return ret;
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}
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static inline int atomic_futex_op_xchg_add(int oparg, int __user *uaddr, int *_oldval)
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{
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int oldval, ret;
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asm("0: \n"
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" orcc gr0,gr0,gr0,icc3 \n" /* set ICC3.Z */
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" ckeq icc3,cc7 \n"
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"1: ld.p %M0,%1 \n" /* LD.P/ORCR must be atomic */
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" orcr cc7,cc7,cc3 \n" /* set CC3 to true */
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" add %1,%3,%3 \n"
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"2: cst.p %3,%M0 ,cc3,#1 \n"
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" corcc gr29,gr29,gr0 ,cc3,#1 \n" /* clear ICC3.Z if store happens */
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" beq icc3,#0,0b \n"
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" setlos 0,%2 \n"
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"3: \n"
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".subsection 2 \n"
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"4: setlos %5,%2 \n"
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" bra 3b \n"
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".previous \n"
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".section __ex_table,\"a\" \n"
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" .balign 8 \n"
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" .long 1b,4b \n"
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" .long 2b,4b \n"
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".previous"
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: "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
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: "3"(oparg), "i"(-EFAULT)
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: "memory", "cc7", "cc3", "icc3"
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);
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*_oldval = oldval;
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return ret;
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}
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static inline int atomic_futex_op_xchg_or(int oparg, int __user *uaddr, int *_oldval)
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{
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int oldval, ret;
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asm("0: \n"
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" orcc gr0,gr0,gr0,icc3 \n" /* set ICC3.Z */
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" ckeq icc3,cc7 \n"
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"1: ld.p %M0,%1 \n" /* LD.P/ORCR must be atomic */
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" orcr cc7,cc7,cc3 \n" /* set CC3 to true */
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" or %1,%3,%3 \n"
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"2: cst.p %3,%M0 ,cc3,#1 \n"
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" corcc gr29,gr29,gr0 ,cc3,#1 \n" /* clear ICC3.Z if store happens */
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" beq icc3,#0,0b \n"
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" setlos 0,%2 \n"
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"3: \n"
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".subsection 2 \n"
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"4: setlos %5,%2 \n"
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" bra 3b \n"
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".previous \n"
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".section __ex_table,\"a\" \n"
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" .balign 8 \n"
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" .long 1b,4b \n"
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" .long 2b,4b \n"
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".previous"
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: "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
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: "3"(oparg), "i"(-EFAULT)
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: "memory", "cc7", "cc3", "icc3"
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);
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*_oldval = oldval;
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return ret;
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}
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static inline int atomic_futex_op_xchg_and(int oparg, int __user *uaddr, int *_oldval)
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{
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int oldval, ret;
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asm("0: \n"
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" orcc gr0,gr0,gr0,icc3 \n" /* set ICC3.Z */
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" ckeq icc3,cc7 \n"
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"1: ld.p %M0,%1 \n" /* LD.P/ORCR must be atomic */
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" orcr cc7,cc7,cc3 \n" /* set CC3 to true */
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" and %1,%3,%3 \n"
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"2: cst.p %3,%M0 ,cc3,#1 \n"
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" corcc gr29,gr29,gr0 ,cc3,#1 \n" /* clear ICC3.Z if store happens */
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" beq icc3,#0,0b \n"
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" setlos 0,%2 \n"
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"3: \n"
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".subsection 2 \n"
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"4: setlos %5,%2 \n"
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" bra 3b \n"
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".previous \n"
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".section __ex_table,\"a\" \n"
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" .balign 8 \n"
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" .long 1b,4b \n"
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" .long 2b,4b \n"
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".previous"
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: "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
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: "3"(oparg), "i"(-EFAULT)
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: "memory", "cc7", "cc3", "icc3"
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);
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*_oldval = oldval;
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return ret;
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}
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static inline int atomic_futex_op_xchg_xor(int oparg, int __user *uaddr, int *_oldval)
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{
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int oldval, ret;
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asm("0: \n"
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" orcc gr0,gr0,gr0,icc3 \n" /* set ICC3.Z */
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" ckeq icc3,cc7 \n"
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"1: ld.p %M0,%1 \n" /* LD.P/ORCR must be atomic */
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" orcr cc7,cc7,cc3 \n" /* set CC3 to true */
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" xor %1,%3,%3 \n"
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"2: cst.p %3,%M0 ,cc3,#1 \n"
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" corcc gr29,gr29,gr0 ,cc3,#1 \n" /* clear ICC3.Z if store happens */
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" beq icc3,#0,0b \n"
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" setlos 0,%2 \n"
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"3: \n"
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".subsection 2 \n"
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"4: setlos %5,%2 \n"
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" bra 3b \n"
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".previous \n"
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".section __ex_table,\"a\" \n"
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" .balign 8 \n"
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" .long 1b,4b \n"
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" .long 2b,4b \n"
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".previous"
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: "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
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: "3"(oparg), "i"(-EFAULT)
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: "memory", "cc7", "cc3", "icc3"
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);
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*_oldval = oldval;
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return ret;
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}
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/*****************************************************************************/
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/*
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* do the futex operations
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*/
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int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
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{
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int op = (encoded_op >> 28) & 7;
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int cmp = (encoded_op >> 24) & 15;
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int oparg = (encoded_op << 8) >> 20;
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int cmparg = (encoded_op << 20) >> 20;
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int oldval = 0, ret;
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if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
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oparg = 1 << oparg;
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if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
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return -EFAULT;
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inc_preempt_count();
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switch (op) {
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case FUTEX_OP_SET:
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ret = atomic_futex_op_xchg_set(oparg, uaddr, &oldval);
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break;
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case FUTEX_OP_ADD:
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ret = atomic_futex_op_xchg_add(oparg, uaddr, &oldval);
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break;
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case FUTEX_OP_OR:
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ret = atomic_futex_op_xchg_or(oparg, uaddr, &oldval);
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break;
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case FUTEX_OP_ANDN:
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ret = atomic_futex_op_xchg_and(~oparg, uaddr, &oldval);
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break;
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case FUTEX_OP_XOR:
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ret = atomic_futex_op_xchg_xor(oparg, uaddr, &oldval);
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break;
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default:
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ret = -ENOSYS;
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break;
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}
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dec_preempt_count();
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if (!ret) {
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switch (cmp) {
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case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
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case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
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case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
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case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
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case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
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case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
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default: ret = -ENOSYS; break;
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}
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}
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return ret;
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} /* end futex_atomic_op_inuser() */
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