LXR linux/arch/tile/lib/usercopy

   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 */
  27STD_ENTRY(strnlen_user_asm)
  28        { beqz r1, 2f; addi r3, r0, -1 }  /* bias down to include NUL */
  291:      { ld1u r4, r0; addi r1, r1, -1 }
  30        beqz r4, 2f
  31        { bnezt r1, 1b; addi r0, r0, 1 }
  322:      { sub r0, r0, r3; jrp lr }
  33        STD_ENDPROC(strnlen_user_asm)
  34        .pushsection .fixup,"ax"
  35strnlen_user_fault:
  36        { move r0, zero; jrp lr }
  37        ENDPROC(strnlen_user_fault)
  38        .section __ex_table,"a"
  39        .align 8
  40        .quad 1b, strnlen_user_fault
  41        .popsection
  42
  43/*
  44 * strncpy_from_user_asm takes the kernel target pointer in r0,
  45 * the userspace source pointer in r1, and the length bound (including
  46 * the trailing NUL) in r2.  On success, it returns the string length
  47 * (not including the trailing NUL), or -EFAULT on failure.
  48 */
  49STD_ENTRY(strncpy_from_user_asm)
  50        { beqz r2, 2f; move r3, r0 }
  511:      { ld1u r4, r1; addi r1, r1, 1; addi r2, r2, -1 }
  52        { st1 r0, r4; addi r0, r0, 1 }
  53        beqz r4, 2f
  54        bnezt r2, 1b
  55        { sub r0, r0, r3; jrp lr }
  562:      addi r0, r0, -1   /* don't count the trailing NUL */
  57        { sub r0, r0, r3; jrp lr }
  58        STD_ENDPROC(strncpy_from_user_asm)
  59        .pushsection .fixup,"ax"
  60strncpy_from_user_fault:
  61        { movei r0, -EFAULT; jrp lr }
  62        ENDPROC(strncpy_from_user_fault)
  63        .section __ex_table,"a"
  64        .align 8
  65        .quad 1b, strncpy_from_user_fault
  66        .popsection
  67
  68/*
  69 * clear_user_asm takes the user target address in r0 and the
  70 * number of bytes to zero in r1.
  71 * It returns the number of uncopiable bytes (hopefully zero) in r0.
  72 * Note that we don't use a separate .fixup section here since we fall
  73 * through into the "fixup" code as the last straight-line bundle anyway.
  74 */
  75STD_ENTRY(clear_user_asm)
  76        { beqz r1, 2f; or r2, r0, r1 }
  77        andi r2, r2, 7
  78        beqzt r2, .Lclear_aligned_user_asm
  791:      { st1 r0, zero; addi r0, r0, 1; addi r1, r1, -1 }
  80        bnezt r1, 1b
  812:      { move r0, r1; jrp lr }
  82        .pushsection __ex_table,"a"
  83        .align 8
  84        .quad 1b, 2b
  85        .popsection
  86
  87.Lclear_aligned_user_asm:
  881:      { st r0, zero; addi r0, r0, 8; addi r1, r1, -8 }
  89        bnezt r1, 1b
  902:      { move r0, r1; jrp lr }
  91        STD_ENDPROC(clear_user_asm)
  92        .pushsection __ex_table,"a"
  93        .align 8
  94        .quad 1b, 2b
  95        .popsection
  96
  97/*
  98 * flush_user_asm takes the user target address in r0 and the
  99 * number of bytes to flush in r1.
 100 * It returns the number of unflushable bytes (hopefully zero) in r0.
 101 */
 102STD_ENTRY(flush_user_asm)
 103        beqz r1, 2f
 104        { movei r2, L2_CACHE_BYTES; add r1, r0, r1 }
 105        { sub r2, zero, r2; addi r1, r1, L2_CACHE_BYTES-1 }
 106        { and r0, r0, r2; and r1, r1, r2 }
 107        { sub r1, r1, r0 }
 1081:      { flush r0; addi r1, r1, -CHIP_FLUSH_STRIDE() }
 109        { addi r0, r0, CHIP_FLUSH_STRIDE(); bnezt r1, 1b }
 1102:      { move r0, r1; jrp lr }
 111        STD_ENDPROC(flush_user_asm)
 112        .pushsection __ex_table,"a"
 113        .align 8
 114        .quad 1b, 2b
 115        .popsection
 116
 117/*
 118 * finv_user_asm takes the user target address in r0 and the
 119 * number of bytes to flush-invalidate in r1.
 120 * It returns the number of not finv'able bytes (hopefully zero) in r0.
 121 */
 122STD_ENTRY(finv_user_asm)
 123        beqz r1, 2f
 124        { movei r2, L2_CACHE_BYTES; add r1, r0, r1 }
 125        { sub r2, zero, r2; addi r1, r1, L2_CACHE_BYTES-1 }
 126        { and r0, r0, r2; and r1, r1, r2 }
 127        { sub r1, r1, r0 }
 1281:      { finv r0; addi r1, r1, -CHIP_FINV_STRIDE() }
 129        { addi r0, r0, CHIP_FINV_STRIDE(); bnezt r1, 1b }
 1302:      { move r0, r1; jrp lr }
 131        STD_ENDPROC(finv_user_asm)
 132        .pushsection __ex_table,"a"
 133        .align 8
 134        .quad 1b, 2b
 135        .popsection
 136