181 строка
4.0 KiB
ArmAsm
181 строка
4.0 KiB
ArmAsm
/*
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* User Space Access Routines
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*
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* Copyright (C) 2000-2002 Hewlett-Packard (John Marvin)
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* Copyright (C) 2000 Richard Hirst <rhirst with parisc-linux.org>
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* Copyright (C) 2001 Matthieu Delahaye <delahaym at esiee.fr>
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* Copyright (C) 2003 Randolph Chung <tausq with parisc-linux.org>
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*
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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/*
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* These routines still have plenty of room for optimization
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* (word & doubleword load/store, dual issue, store hints, etc.).
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*/
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/*
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* The following routines assume that space register 3 (sr3) contains
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* the space id associated with the current users address space.
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*/
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.text
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#include <asm/assembly.h>
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#include <asm/errno.h>
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#include <linux/linkage.h>
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/*
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* get_sr gets the appropriate space value into
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* sr1 for kernel/user space access, depending
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* on the flag stored in the task structure.
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*/
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.macro get_sr
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mfctl %cr30,%r1
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ldw TI_SEGMENT(%r1),%r22
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mfsp %sr3,%r1
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or,<> %r22,%r0,%r0
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copy %r0,%r1
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mtsp %r1,%sr1
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.endm
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.macro fixup_branch lbl
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ldil L%\lbl, %r1
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ldo R%\lbl(%r1), %r1
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bv %r0(%r1)
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.endm
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/*
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* long lstrncpy_from_user(char *dst, const char *src, long n)
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*
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* Returns -EFAULT if exception before terminator,
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* N if the entire buffer filled,
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* otherwise strlen (i.e. excludes zero byte)
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*/
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ENTRY(lstrncpy_from_user)
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.proc
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.callinfo NO_CALLS
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.entry
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comib,= 0,%r24,$lsfu_done
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copy %r24,%r23
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get_sr
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1: ldbs,ma 1(%sr1,%r25),%r1
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$lsfu_loop:
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stbs,ma %r1,1(%r26)
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comib,=,n 0,%r1,$lsfu_done
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addib,<>,n -1,%r24,$lsfu_loop
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2: ldbs,ma 1(%sr1,%r25),%r1
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$lsfu_done:
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sub %r23,%r24,%r28
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$lsfu_exit:
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bv %r0(%r2)
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nop
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.exit
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ENDPROC(lstrncpy_from_user)
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.section .fixup,"ax"
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3: fixup_branch $lsfu_exit
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ldi -EFAULT,%r28
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.previous
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.section __ex_table,"aw"
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ASM_ULONG_INSN 1b,3b
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ASM_ULONG_INSN 2b,3b
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.previous
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.procend
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/*
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* unsigned long lclear_user(void *to, unsigned long n)
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*
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* Returns 0 for success.
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* otherwise, returns number of bytes not transferred.
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*/
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ENTRY(lclear_user)
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.proc
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.callinfo NO_CALLS
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.entry
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comib,=,n 0,%r25,$lclu_done
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get_sr
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$lclu_loop:
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addib,<> -1,%r25,$lclu_loop
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1: stbs,ma %r0,1(%sr1,%r26)
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$lclu_done:
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bv %r0(%r2)
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copy %r25,%r28
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.exit
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ENDPROC(lclear_user)
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.section .fixup,"ax"
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2: fixup_branch $lclu_done
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ldo 1(%r25),%r25
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.previous
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.section __ex_table,"aw"
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ASM_ULONG_INSN 1b,2b
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.previous
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.procend
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/*
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* long lstrnlen_user(char *s, long n)
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*
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* Returns 0 if exception before zero byte or reaching N,
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* N+1 if N would be exceeded,
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* else strlen + 1 (i.e. includes zero byte).
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*/
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ENTRY(lstrnlen_user)
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.proc
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.callinfo NO_CALLS
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.entry
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comib,= 0,%r25,$lslen_nzero
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copy %r26,%r24
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get_sr
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1: ldbs,ma 1(%sr1,%r26),%r1
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$lslen_loop:
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comib,=,n 0,%r1,$lslen_done
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addib,<> -1,%r25,$lslen_loop
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2: ldbs,ma 1(%sr1,%r26),%r1
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$lslen_done:
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bv %r0(%r2)
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sub %r26,%r24,%r28
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.exit
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$lslen_nzero:
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b $lslen_done
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ldo 1(%r26),%r26 /* special case for N == 0 */
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ENDPROC(lstrnlen_user)
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.section .fixup,"ax"
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3: fixup_branch $lslen_done
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copy %r24,%r26 /* reset r26 so 0 is returned on fault */
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.previous
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.section __ex_table,"aw"
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ASM_ULONG_INSN 1b,3b
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ASM_ULONG_INSN 2b,3b
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.previous
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.procend
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.end
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