a866374aec
Introduce pagefault_{disable,enable}() and use these where previously we did
manual preempt increments/decrements to make the pagefault handler do the
atomic thing.
Currently they still rely on the increased preempt count, but do not rely on
the disabled preemption, this might go away in the future.
(NOTE: the extra barrier() in pagefault_disable might fix some holes on
machines which have too many registers for their own good)
[heiko.carstens@de.ibm.com: s390 fix]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Nick Piggin <npiggin@suse.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
203 lines
5.1 KiB
C
203 lines
5.1 KiB
C
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (c) 2006 Ralf Baechle (ralf@linux-mips.org)
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*/
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#ifndef _ASM_FUTEX_H
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#define _ASM_FUTEX_H
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#ifdef __KERNEL__
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#include <linux/futex.h>
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#include <asm/barrier.h>
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#include <asm/errno.h>
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#include <asm/uaccess.h>
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#include <asm/war.h>
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#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
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{ \
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if (cpu_has_llsc && R10000_LLSC_WAR) { \
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__asm__ __volatile__( \
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" .set push \n" \
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" .set noat \n" \
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" .set mips3 \n" \
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"1: ll %1, %4 # __futex_atomic_op \n" \
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" .set mips0 \n" \
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" " insn " \n" \
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" .set mips3 \n" \
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"2: sc $1, %2 \n" \
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" beqzl $1, 1b \n" \
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__WEAK_ORDERING_MB \
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"3: \n" \
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" .set pop \n" \
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" .set mips0 \n" \
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" .section .fixup,\"ax\" \n" \
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"4: li %0, %6 \n" \
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" j 2b \n" \
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" .previous \n" \
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" .section __ex_table,\"a\" \n" \
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" "__UA_ADDR "\t1b, 4b \n" \
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" "__UA_ADDR "\t2b, 4b \n" \
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" .previous \n" \
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: "=r" (ret), "=&r" (oldval), "=R" (*uaddr) \
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: "0" (0), "R" (*uaddr), "Jr" (oparg), "i" (-EFAULT) \
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: "memory"); \
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} else if (cpu_has_llsc) { \
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__asm__ __volatile__( \
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" .set push \n" \
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" .set noat \n" \
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" .set mips3 \n" \
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"1: ll %1, %4 # __futex_atomic_op \n" \
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" .set mips0 \n" \
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" " insn " \n" \
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" .set mips3 \n" \
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"2: sc $1, %2 \n" \
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" beqz $1, 1b \n" \
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__WEAK_ORDERING_MB \
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"3: \n" \
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" .set pop \n" \
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" .set mips0 \n" \
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" .section .fixup,\"ax\" \n" \
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"4: li %0, %6 \n" \
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" j 2b \n" \
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" .previous \n" \
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" .section __ex_table,\"a\" \n" \
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" "__UA_ADDR "\t1b, 4b \n" \
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" "__UA_ADDR "\t2b, 4b \n" \
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" .previous \n" \
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: "=r" (ret), "=&r" (oldval), "=R" (*uaddr) \
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: "0" (0), "R" (*uaddr), "Jr" (oparg), "i" (-EFAULT) \
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: "memory"); \
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} else \
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ret = -ENOSYS; \
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}
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static inline int
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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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pagefault_disable();
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switch (op) {
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case FUTEX_OP_SET:
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__futex_atomic_op("move $1, %z5", ret, oldval, uaddr, oparg);
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break;
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case FUTEX_OP_ADD:
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__futex_atomic_op("addu $1, %1, %z5",
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ret, oldval, uaddr, oparg);
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break;
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case FUTEX_OP_OR:
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__futex_atomic_op("or $1, %1, %z5",
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ret, oldval, uaddr, oparg);
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break;
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case FUTEX_OP_ANDN:
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__futex_atomic_op("and $1, %1, %z5",
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ret, oldval, uaddr, ~oparg);
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break;
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case FUTEX_OP_XOR:
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__futex_atomic_op("xor $1, %1, %z5",
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ret, oldval, uaddr, oparg);
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break;
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default:
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ret = -ENOSYS;
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}
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pagefault_enable();
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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;
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}
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}
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return ret;
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}
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static inline int
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futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
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{
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int retval;
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if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
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return -EFAULT;
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if (cpu_has_llsc && R10000_LLSC_WAR) {
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__asm__ __volatile__(
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"# futex_atomic_cmpxchg_inatomic \n"
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" .set push \n"
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" .set noat \n"
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" .set mips3 \n"
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"1: ll %0, %2 \n"
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" bne %0, %z3, 3f \n"
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" .set mips0 \n"
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" move $1, %z4 \n"
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" .set mips3 \n"
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"2: sc $1, %1 \n"
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" beqzl $1, 1b \n"
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__WEAK_ORDERING_MB
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"3: \n"
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" .set pop \n"
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" .section .fixup,\"ax\" \n"
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"4: li %0, %5 \n"
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" j 3b \n"
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" .previous \n"
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" .section __ex_table,\"a\" \n"
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" "__UA_ADDR "\t1b, 4b \n"
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" "__UA_ADDR "\t2b, 4b \n"
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" .previous \n"
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: "=&r" (retval), "=R" (*uaddr)
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: "R" (*uaddr), "Jr" (oldval), "Jr" (newval), "i" (-EFAULT)
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: "memory");
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} else if (cpu_has_llsc) {
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__asm__ __volatile__(
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"# futex_atomic_cmpxchg_inatomic \n"
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" .set push \n"
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" .set noat \n"
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" .set mips3 \n"
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"1: ll %0, %2 \n"
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" bne %0, %z3, 3f \n"
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" .set mips0 \n"
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" move $1, %z4 \n"
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" .set mips3 \n"
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"2: sc $1, %1 \n"
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" beqz $1, 1b \n"
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__WEAK_ORDERING_MB
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"3: \n"
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" .set pop \n"
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" .section .fixup,\"ax\" \n"
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"4: li %0, %5 \n"
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" j 3b \n"
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" .previous \n"
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" .section __ex_table,\"a\" \n"
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" "__UA_ADDR "\t1b, 4b \n"
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" "__UA_ADDR "\t2b, 4b \n"
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" .previous \n"
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: "=&r" (retval), "=R" (*uaddr)
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: "R" (*uaddr), "Jr" (oldval), "Jr" (newval), "i" (-EFAULT)
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: "memory");
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} else
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return -ENOSYS;
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return retval;
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}
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#endif
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#endif
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