arch/arm26/lib/getuser.S

   1 /*
   2  *  linux/arch/arm26/lib/getuser.S
   3  *
   4  *  Copyright (C) 2001 Russell King
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  *  Idea from x86 version, (C) Copyright 1998 Linus Torvalds
  11  *
  12  * These functions have a non-standard call interface to make them more
  13  * efficient, especially as they return an error value in addition to
  14  * the "real" return value.
  15  *
  16  * __get_user_X
  17  *
  18  * Inputs:      r0 contains the address
  19  * Outputs:     r0 is the error code
  20  *              r1, r2 contains the zero-extended value
  21  *              lr corrupted
  22  *
  23  * No other registers must be altered.  (see include/asm-arm/uaccess.h
  24  * for specific ASM register usage).
  25  *
  26  * Note that ADDR_LIMIT is either 0 or 0xc0000000.
  27  * Note also that it is intended that __get_user_bad is not global.
  28  */
  29 #include <asm/asm_offsets.h>
  30 #include <asm/thread_info.h>
  31 #include <asm/errno.h>
  32
  33         .global __get_user_1
  34 __get_user_1:
  35         bic     r1, sp, #0x1f00
  36         bic     r1, r1, #0x00ff
  37         str     lr, [sp, #-4]!
  38         ldr     r1, [r1, #TI_ADDR_LIMIT]
  39         sub     r1, r1, #1
  40         cmp     r0, r1
  41         bge     __get_user_bad
  42         cmp     r0, #0x02000000
  43 1:      ldrlsbt r1, [r0]
  44         ldrgeb  r1, [r0]
  45         mov     r0, #0
  46         ldmfd   sp!, {pc}^
  47
  48         .global __get_user_2
  49 __get_user_2:
  50         bic     r2, sp, #0x1f00
  51         bic     r2, r2, #0x00ff
  52         str     lr, [sp, #-4]!
  53         ldr     r2, [r2, #TI_ADDR_LIMIT]
  54         sub     r2, r2, #2
  55         cmp     r0, r2
  56         bge     __get_user_bad
  57         cmp     r0, #0x02000000
  58 2:      ldrlsbt r1, [r0], #1
  59 3:      ldrlsbt r2, [r0]
  60         ldrgeb  r1, [r0], #1
  61         ldrgeb  r2, [r0]
  62         orr     r1, r1, r2, lsl #8
  63         mov     r0, #0
  64         ldmfd   sp!, {pc}^
  65
  66         .global __get_user_4
  67 __get_user_4:
  68         bic     r1, sp, #0x1f00
  69         bic     r1, r1, #0x00ff
  70         str     lr, [sp, #-4]!
  71         ldr     r1, [r1, #TI_ADDR_LIMIT]
  72         sub     r1, r1, #4
  73         cmp     r0, r1
  74         bge     __get_user_bad
  75         cmp     r0, #0x02000000
  76 4:      ldrlst  r1, [r0]
  77         ldrge   r1, [r0]
  78         mov     r0, #0
  79         ldmfd   sp!, {pc}^
  80
  81         .global __get_user_8
  82 __get_user_8:
  83         bic     r2, sp, #0x1f00
  84         bic     r2, r2, #0x00ff
  85         str     lr, [sp, #-4]!
  86         ldr     r2, [r2, #TI_ADDR_LIMIT]
  87         sub     r2, r2, #8
  88         cmp     r0, r2
  89         bge     __get_user_bad_8
  90         cmp     r0, #0x02000000
  91 5:      ldrlst  r1, [r0], #4
  92 6:      ldrlst  r2, [r0]
  93         ldrge   r1, [r0], #4
  94         ldrge   r2, [r0]
  95         mov     r0, #0
  96         ldmfd   sp!, {pc}^
  97
  98 __get_user_bad_8:
  99         mov     r2, #0
 100 __get_user_bad:
 101         mov     r1, #0
 102         mov     r0, #-EFAULT
 103         ldmfd   sp!, {pc}^
 104
 105 .section __ex_table, "a"
 106         .long   1b, __get_user_bad
 107         .long   2b, __get_user_bad
 108         .long   3b, __get_user_bad
 109         .long   4b, __get_user_bad
 110         .long   5b, __get_user_bad_8
 111         .long   6b, __get_user_bad_8
 112 .previous