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  1. /*
  2.  * Copyright (C) 2006 Jakub Jermar
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /**
  30.  * @file    copy.c
  31.  * @brief   Copying between kernel and userspace.
  32.  *
  33.  * This file contains sanitized functions for copying data
  34.  * between kernel and userspace.
  35.  */
  36.  
  37. #include <syscall/copy.h>
  38. #include <proc/thread.h>
  39. #include <mm/as.h>
  40. #include <macros.h>
  41. #include <arch.h>
  42. #include <errno.h>
  43. #include <typedefs.h>
  44.  
  45. /** Copy data from userspace to kernel.
  46.  *
  47.  * Provisions are made to return value even after page fault.
  48.  *
  49.  * This function can be called only from syscall.
  50.  *
  51.  * @param dst Destination kernel address.
  52.  * @param uspace_src Source userspace address.
  53.  * @param size Size of the data to be copied.
  54.  *
  55.  * @return 0 on success or error code from @ref errno.h.
  56.  */
  57. int copy_from_uspace(void *dst, const void *uspace_src, size_t size)
  58. {
  59.     ipl_t ipl;
  60.     int rc;
  61.    
  62.     ASSERT(THREAD);
  63.     ASSERT(!THREAD->in_copy_from_uspace);
  64.    
  65.     if (!KERNEL_ADDRESS_SPACE_SHADOWED) {
  66.         if (overlaps((__address) uspace_src, size,
  67.             KERNEL_ADDRESS_SPACE_START, KERNEL_ADDRESS_SPACE_END-KERNEL_ADDRESS_SPACE_START)) {
  68.             /*
  69.              * The userspace source block conflicts with kernel address space.
  70.              */
  71.             return EPERM;
  72.         }
  73.     }
  74.    
  75.     ipl = interrupts_disable();
  76.     THREAD->in_copy_from_uspace = true;
  77.    
  78.     rc = memcpy_from_uspace(dst, uspace_src, size);
  79.  
  80.     THREAD->in_copy_from_uspace = false;
  81.  
  82.     interrupts_restore(ipl);
  83.     return !rc ? EPERM : 0;
  84. }
  85.  
  86. /** Copy data from kernel to userspace.
  87.  *
  88.  * Provisions are made to return value even after page fault.
  89.  *
  90.  * This function can be called only from syscall.
  91.  *
  92.  * @param uspace_dst Destination userspace address.
  93.  * @param uspace_src Source kernel address.
  94.  * @param size Size of the data to be copied.
  95.  *
  96.  * @return 0 on success or error code from @ref errno.h.
  97.  */
  98. int copy_to_uspace(void *uspace_dst, const void *src, size_t size)
  99. {
  100.     ipl_t ipl;
  101.     int rc;
  102.    
  103.     ASSERT(THREAD);
  104.     ASSERT(!THREAD->in_copy_from_uspace);
  105.    
  106.     if (!KERNEL_ADDRESS_SPACE_SHADOWED) {
  107.         if (overlaps((__address) uspace_dst, size,
  108.             KERNEL_ADDRESS_SPACE_START, KERNEL_ADDRESS_SPACE_END-KERNEL_ADDRESS_SPACE_START)) {
  109.             /*
  110.              * The userspace destination block conflicts with kernel address space.
  111.              */
  112.             return EPERM;
  113.         }
  114.     }
  115.    
  116.     ipl = interrupts_disable();
  117.     THREAD->in_copy_from_uspace = true;
  118.    
  119.     rc = memcpy_to_uspace(uspace_dst, src, size);
  120.  
  121.     THREAD->in_copy_from_uspace = false;
  122.  
  123.     interrupts_restore(ipl);
  124.     return !rc ? EPERM : 0;
  125. }
  126.