324 lines
8.3 KiB
C
324 lines
8.3 KiB
C
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/* uaccess.h: userspace accessor functions
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*
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* Copyright (C) 2004 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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#ifndef _ASM_UACCESS_H
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#define _ASM_UACCESS_H
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/*
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* User space memory access functions
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*/
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <asm/segment.h>
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#include <asm/sections.h>
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#define __ptr(x) ((unsigned long __force *)(x))
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#define VERIFY_READ 0
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#define VERIFY_WRITE 1
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/*
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* check that a range of addresses falls within the current address limit
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*/
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static inline int ___range_ok(unsigned long addr, unsigned long size)
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{
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#ifdef CONFIG_MMU
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int flag = -EFAULT, tmp;
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asm volatile (
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" addcc %3,%2,%1,icc0 \n" /* set C-flag if addr+size>4GB */
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" subcc.p %1,%4,gr0,icc1 \n" /* jump if addr+size>limit */
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" bc icc0,#0,0f \n"
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" bhi icc1,#0,0f \n"
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" setlos #0,%0 \n" /* mark okay */
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"0: \n"
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: "=r"(flag), "=&r"(tmp)
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: "r"(addr), "r"(size), "r"(get_addr_limit()), "0"(flag)
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);
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return flag;
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#else
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if (addr < memory_start ||
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addr > memory_end ||
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size > memory_end - memory_start ||
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addr + size > memory_end)
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return -EFAULT;
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return 0;
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#endif
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}
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#define __range_ok(addr,size) ___range_ok((unsigned long) (addr), (unsigned long) (size))
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#define access_ok(type,addr,size) (__range_ok((void __user *)(addr), (size)) == 0)
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#define __access_ok(addr,size) (__range_ok((addr), (size)) == 0)
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/*
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* The exception table consists of pairs of addresses: the first is the
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* address of an instruction that is allowed to fault, and the second is
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* the address at which the program should continue. No registers are
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* modified, so it is entirely up to the continuation code to figure out
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* what to do.
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*
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* All the routines below use bits of fixup code that are out of line
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* with the main instruction path. This means when everything is well,
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* we don't even have to jump over them. Further, they do not intrude
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* on our cache or tlb entries.
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*/
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struct exception_table_entry
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{
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unsigned long insn, fixup;
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};
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/* Returns 0 if exception not found and fixup otherwise. */
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extern unsigned long search_exception_table(unsigned long);
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/*
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* These are the main single-value transfer routines. They automatically
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* use the right size if we just have the right pointer type.
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*/
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#define __put_user(x, ptr) \
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({ \
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int __pu_err = 0; \
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\
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typeof(*(ptr)) __pu_val = (x); \
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__chk_user_ptr(ptr); \
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\
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switch (sizeof (*(ptr))) { \
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case 1: \
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__put_user_asm(__pu_err, __pu_val, ptr, "b", "r"); \
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break; \
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case 2: \
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__put_user_asm(__pu_err, __pu_val, ptr, "h", "r"); \
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break; \
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case 4: \
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__put_user_asm(__pu_err, __pu_val, ptr, "", "r"); \
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break; \
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case 8: \
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__put_user_asm(__pu_err, __pu_val, ptr, "d", "e"); \
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break; \
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default: \
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__pu_err = __put_user_bad(); \
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break; \
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} \
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__pu_err; \
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})
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#define put_user(x, ptr) \
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({ \
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typeof(*(ptr)) __user *_p = (ptr); \
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int _e; \
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\
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_e = __range_ok(_p, sizeof(*_p)); \
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if (_e == 0) \
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_e = __put_user((x), _p); \
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_e; \
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})
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extern int __put_user_bad(void);
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/*
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* Tell gcc we read from memory instead of writing: this is because
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* we do not write to any memory gcc knows about, so there are no
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* aliasing issues.
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*/
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#ifdef CONFIG_MMU
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#define __put_user_asm(err,x,ptr,dsize,constraint) \
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do { \
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asm volatile("1: st"dsize"%I1 %2,%M1 \n" \
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"2: \n" \
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".subsection 2 \n" \
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"3: setlos %3,%0 \n" \
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" bra 2b \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,3b \n" \
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".previous" \
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: "=r" (err) \
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: "m" (*__ptr(ptr)), constraint (x), "i"(-EFAULT), "0"(err) \
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: "memory"); \
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} while (0)
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#else
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#define __put_user_asm(err,x,ptr,bwl,con) \
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do { \
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asm(" st"bwl"%I0 %1,%M0 \n" \
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" membar \n" \
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: \
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: "m" (*__ptr(ptr)), con (x) \
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: "memory"); \
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} while (0)
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#endif
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/*****************************************************************************/
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/*
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*
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*/
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#define __get_user(x, ptr) \
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({ \
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int __gu_err = 0; \
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__chk_user_ptr(ptr); \
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\
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switch (sizeof(*(ptr))) { \
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case 1: { \
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unsigned char __gu_val; \
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__get_user_asm(__gu_err, __gu_val, ptr, "ub", "=r"); \
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(x) = *(__force __typeof__(*(ptr)) *) &__gu_val; \
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break; \
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} \
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case 2: { \
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unsigned short __gu_val; \
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__get_user_asm(__gu_err, __gu_val, ptr, "uh", "=r"); \
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(x) = *(__force __typeof__(*(ptr)) *) &__gu_val; \
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break; \
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} \
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case 4: { \
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unsigned int __gu_val; \
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__get_user_asm(__gu_err, __gu_val, ptr, "", "=r"); \
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(x) = *(__force __typeof__(*(ptr)) *) &__gu_val; \
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break; \
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} \
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case 8: { \
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unsigned long long __gu_val; \
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__get_user_asm(__gu_err, __gu_val, ptr, "d", "=e"); \
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(x) = *(__force __typeof__(*(ptr)) *) &__gu_val; \
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break; \
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} \
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default: \
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__gu_err = __get_user_bad(); \
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break; \
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} \
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__gu_err; \
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})
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#define get_user(x, ptr) \
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({ \
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const typeof(*(ptr)) __user *_p = (ptr);\
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int _e; \
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\
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_e = __range_ok(_p, sizeof(*_p)); \
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if (likely(_e == 0)) \
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_e = __get_user((x), _p); \
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else \
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(x) = (typeof(x)) 0; \
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_e; \
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})
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extern int __get_user_bad(void);
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#ifdef CONFIG_MMU
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#define __get_user_asm(err,x,ptr,dtype,constraint) \
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do { \
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asm("1: ld"dtype"%I2 %M2,%1 \n" \
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"2: \n" \
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".subsection 2 \n" \
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"3: setlos %3,%0 \n" \
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" setlos #0,%1 \n" \
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" bra 2b \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,3b \n" \
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".previous" \
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: "=r" (err), constraint (x) \
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: "m" (*__ptr(ptr)), "i"(-EFAULT), "0"(err) \
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); \
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} while(0)
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#else
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#define __get_user_asm(err,x,ptr,bwl,con) \
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asm(" ld"bwl"%I1 %M1,%0 \n" \
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" membar \n" \
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: con(x) \
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: "m" (*__ptr(ptr)))
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#endif
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/*****************************************************************************/
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/*
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*
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*/
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#define ____force(x) (__force void *)(void __user *)(x)
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#ifdef CONFIG_MMU
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extern long __memset_user(void *dst, unsigned long count);
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extern long __memcpy_user(void *dst, const void *src, unsigned long count);
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#define __clear_user(dst,count) __memset_user(____force(dst), (count))
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#define __copy_from_user_inatomic(to, from, n) __memcpy_user((to), ____force(from), (n))
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#define __copy_to_user_inatomic(to, from, n) __memcpy_user(____force(to), (from), (n))
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#else
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#define __clear_user(dst,count) (memset(____force(dst), 0, (count)), 0)
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#define __copy_from_user_inatomic(to, from, n) (memcpy((to), ____force(from), (n)), 0)
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#define __copy_to_user_inatomic(to, from, n) (memcpy(____force(to), (from), (n)), 0)
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#endif
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static inline unsigned long __must_check
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clear_user(void __user *to, unsigned long n)
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{
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if (likely(__access_ok(to, n)))
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n = __clear_user(to, n);
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return n;
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}
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static inline unsigned long __must_check
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__copy_to_user(void __user *to, const void *from, unsigned long n)
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{
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might_fault();
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return __copy_to_user_inatomic(to, from, n);
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}
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static inline unsigned long
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__copy_from_user(void *to, const void __user *from, unsigned long n)
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{
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might_fault();
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return __copy_from_user_inatomic(to, from, n);
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}
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static inline long copy_from_user(void *to, const void __user *from, unsigned long n)
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{
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unsigned long ret = n;
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if (likely(__access_ok(from, n)))
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ret = __copy_from_user(to, from, n);
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if (unlikely(ret != 0))
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memset(to + (n - ret), 0, ret);
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return ret;
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}
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static inline long copy_to_user(void __user *to, const void *from, unsigned long n)
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{
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return likely(__access_ok(to, n)) ? __copy_to_user(to, from, n) : n;
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}
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extern long strncpy_from_user(char *dst, const char __user *src, long count);
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extern long strnlen_user(const char __user *src, long count);
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#define strlen_user(str) strnlen_user(str, 32767)
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extern unsigned long search_exception_table(unsigned long addr);
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#endif /* _ASM_UACCESS_H */
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