85 lines
2.3 KiB
C
85 lines
2.3 KiB
C
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/*
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* include/asm-xtensa/uaccess.h
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*
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* User space memory access functions
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*
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* These routines provide basic accessing functions to the user memory
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* space for the kernel. This header file provides functions such as:
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*
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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) 2001 - 2005 Tensilica Inc.
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*/
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#ifndef _XTENSA_ASM_UACCESS_H
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#define _XTENSA_ASM_UACCESS_H
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#include <linux/errno.h>
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#include <asm/types.h>
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#include <asm/current.h>
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#include <asm/asm-offsets.h>
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#include <asm/processor.h>
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/*
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* user_ok determines whether the access to user-space memory is allowed.
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* See the equivalent C-macro version below for clarity.
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*
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* On error, user_ok branches to a label indicated by parameter
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* <error>. This implies that the macro falls through to the next
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* instruction on success.
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*
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* Note that while this macro can be used independently, we designed
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* in for optimal use in the access_ok macro below (i.e., we fall
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* through on success).
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*
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* On Entry:
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* <aa> register containing memory address
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* <as> register containing memory size
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* <at> temp register
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* <error> label to branch to on error; implies fall-through
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* macro on success
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* On Exit:
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* <aa> preserved
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* <as> preserved
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* <at> destroyed (actually, (TASK_SIZE + 1 - size))
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*/
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.macro user_ok aa, as, at, error
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movi \at, __XTENSA_UL_CONST(TASK_SIZE)
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bgeu \as, \at, \error
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sub \at, \at, \as
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bgeu \aa, \at, \error
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.endm
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/*
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* access_ok determines whether a memory access is allowed. See the
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* equivalent C-macro version below for clarity.
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*
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* On error, access_ok branches to a label indicated by parameter
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* <error>. This implies that the macro falls through to the next
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* instruction on success.
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*
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* Note that we assume success is the common case, and we optimize the
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* branch fall-through case on success.
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*
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* On Entry:
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* <aa> register containing memory address
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* <as> register containing memory size
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* <at> temp register
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* <sp>
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* <error> label to branch to on error; implies fall-through
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* macro on success
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* On Exit:
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* <aa> preserved
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* <as> preserved
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* <at> destroyed
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*/
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.macro access_ok aa, as, at, sp, error
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user_ok \aa, \as, \at, \error
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.Laccess_ok_\@:
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.endm
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#endif /* _XTENSA_ASM_UACCESS_H */
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