arch/tile/lib/usercopy_64.S

   1 /*
   2  * Copyright 2011 Tilera Corporation. All Rights Reserved.
   3  *
   4  *   This program is free software; you can redistribute it and/or
   5  *   modify it under the terms of the GNU General Public License
   6  *   as published by the Free Software Foundation, version 2.
   7  *
   8  *   This program is distributed in the hope that it will be useful, but
   9  *   WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  11  *   NON INFRINGEMENT.  See the GNU General Public License for
  12  *   more details.
  13  */
  14
  15 #include <linux/linkage.h>
  16 #include <asm/errno.h>
  17 #include <asm/cache.h>
  18 #include <arch/chip.h>
  19
  20 /* Access user memory, but use MMU to avoid propagating kernel exceptions. */
  21
  22 /*
  23  * strnlen_user_asm takes the pointer in r0, and the length bound in r1.
  24  * It returns the length, including the terminating NUL, or zero on exception.
  25  * If length is greater than the bound, returns one plus the bound.
  26  */
  27 STD_ENTRY(strnlen_user_asm)
  28         { beqz r1, 2f; addi r3, r0, -1 }  /* bias down to include NUL */
  29 1:      { ld1u r4, r0; addi r1, r1, -1 }
  30         beqz r4, 2f
  31         { bnezt r1, 1b; addi r0, r0, 1 }
  32 2:      { sub r0, r0, r3; jrp lr }
  33         STD_ENDPROC(strnlen_user_asm)
  34         .pushsection .fixup,"ax"
  35 strnlen_user_fault:
  36         { move r0, zero; jrp lr }
  37         ENDPROC(strnlen_user_fault)
  38         .section __ex_table,"a"
  39         .quad 1b, strnlen_user_fault
  40         .popsection
  41
  42 /*
  43  * strncpy_from_user_asm takes the kernel target pointer in r0,
  44  * the userspace source pointer in r1, and the length bound (including
  45  * the trailing NUL) in r2.  On success, it returns the string length
  46  * (not including the trailing NUL), or -EFAULT on failure.
  47  */
  48 STD_ENTRY(strncpy_from_user_asm)
  49         { beqz r2, 2f; move r3, r0 }
  50 1:      { ld1u r4, r1; addi r1, r1, 1; addi r2, r2, -1 }
  51         { st1 r0, r4; addi r0, r0, 1 }
  52         beqz r2, 2f
  53         bnezt r4, 1b
  54         addi r0, r0, -1   /* don't count the trailing NUL */
  55 2:      { sub r0, r0, r3; jrp lr }
  56         STD_ENDPROC(strncpy_from_user_asm)
  57         .pushsection .fixup,"ax"
  58 strncpy_from_user_fault:
  59         { movei r0, -EFAULT; jrp lr }
  60         ENDPROC(strncpy_from_user_fault)
  61         .section __ex_table,"a"
  62         .quad 1b, strncpy_from_user_fault
  63         .popsection
  64
  65 /*
  66  * clear_user_asm takes the user target address in r0 and the
  67  * number of bytes to zero in r1.
  68  * It returns the number of uncopiable bytes (hopefully zero) in r0.
  69  * Note that we don't use a separate .fixup section here since we fall
  70  * through into the "fixup" code as the last straight-line bundle anyway.
  71  */
  72 STD_ENTRY(clear_user_asm)
  73         { beqz r1, 2f; or r2, r0, r1 }
  74         andi r2, r2, 7
  75         beqzt r2, .Lclear_aligned_user_asm
  76 1:      { st1 r0, zero; addi r0, r0, 1; addi r1, r1, -1 }
  77         bnezt r1, 1b
  78 2:      { move r0, r1; jrp lr }
  79         .pushsection __ex_table,"a"
  80         .quad 1b, 2b
  81         .popsection
  82
  83 .Lclear_aligned_user_asm:
  84 1:      { st r0, zero; addi r0, r0, 8; addi r1, r1, -8 }
  85         bnezt r1, 1b
  86 2:      { move r0, r1; jrp lr }
  87         STD_ENDPROC(clear_user_asm)
  88         .pushsection __ex_table,"a"
  89         .quad 1b, 2b
  90         .popsection
  91
  92 /*
  93  * flush_user_asm takes the user target address in r0 and the
  94  * number of bytes to flush in r1.
  95  * It returns the number of unflushable bytes (hopefully zero) in r0.
  96  */
  97 STD_ENTRY(flush_user_asm)
  98         beqz r1, 2f
  99         { movei r2, L2_CACHE_BYTES; add r1, r0, r1 }
 100         { sub r2, zero, r2; addi r1, r1, L2_CACHE_BYTES-1 }
 101         { and r0, r0, r2; and r1, r1, r2 }
 102         { sub r1, r1, r0 }
 103 1:      { flush r0; addi r1, r1, -CHIP_FLUSH_STRIDE() }
 104         { addi r0, r0, CHIP_FLUSH_STRIDE(); bnezt r1, 1b }
 105 2:      { move r0, r1; jrp lr }
 106         STD_ENDPROC(flush_user_asm)
 107         .pushsection __ex_table,"a"
 108         .quad 1b, 2b
 109         .popsection
 110
 111 /*
 112  * inv_user_asm takes the user target address in r0 and the
 113  * number of bytes to invalidate in r1.
 114  * It returns the number of not inv'able bytes (hopefully zero) in r0.
 115  */
 116 STD_ENTRY(inv_user_asm)
 117         beqz r1, 2f
 118         { movei r2, L2_CACHE_BYTES; add r1, r0, r1 }
 119         { sub r2, zero, r2; addi r1, r1, L2_CACHE_BYTES-1 }
 120         { and r0, r0, r2; and r1, r1, r2 }
 121         { sub r1, r1, r0 }
 122 1:      { inv r0; addi r1, r1, -CHIP_INV_STRIDE() }
 123         { addi r0, r0, CHIP_INV_STRIDE(); bnezt r1, 1b }
 124 2:      { move r0, r1; jrp lr }
 125         STD_ENDPROC(inv_user_asm)
 126         .pushsection __ex_table,"a"
 127         .quad 1b, 2b
 128         .popsection
 129
 130 /*
 131  * finv_user_asm takes the user target address in r0 and the
 132  * number of bytes to flush-invalidate in r1.
 133  * It returns the number of not finv'able bytes (hopefully zero) in r0.
 134  */
 135 STD_ENTRY(finv_user_asm)
 136         beqz r1, 2f
 137         { movei r2, L2_CACHE_BYTES; add r1, r0, r1 }
 138         { sub r2, zero, r2; addi r1, r1, L2_CACHE_BYTES-1 }
 139         { and r0, r0, r2; and r1, r1, r2 }
 140         { sub r1, r1, r0 }
 141 1:      { finv r0; addi r1, r1, -CHIP_FINV_STRIDE() }
 142         { addi r0, r0, CHIP_FINV_STRIDE(); bnezt r1, 1b }
 143 2:      { move r0, r1; jrp lr }
 144         STD_ENDPROC(finv_user_asm)
 145         .pushsection __ex_table,"a"
 146         .quad 1b, 2b
 147         .popsection