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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. /** @addtogroup generic
  30.  * @{
  31.  */
  32.  
  33. /**
  34.  * @file
  35.  * @brief   Copying between kernel and userspace.
  36.  *
  37.  * This file contains sanitized functions for copying data
  38.  * between kernel and userspace.
  39.  */
  40.  
  41. #include <syscall/copy.h>
  42. #include <proc/thread.h>
  43. #include <mm/as.h>
  44. #include <macros.h>
  45. #include <arch.h>
  46. #include <errno.h>
  47.  
  48. /** Copy data from userspace to kernel.
  49.  *
  50.  * Provisions are made to return value even after page fault.
  51.  *
  52.  * This function can be called only from syscall.
  53.  *
  54.  * @param dst Destination kernel address.
  55.  * @param uspace_src Source userspace address.
  56.  * @param size Size of the data to be copied.
  57.  *
  58.  * @return 0 on success or error code from @ref errno.h.
  59.  */
  60. int copy_from_uspace(void *dst, const void *uspace_src, size_t size)
  61. {
  62.     ipl_t ipl;
  63.     int rc;
  64.    
  65.     ASSERT(THREAD);
  66.     ASSERT(!THREAD->in_copy_from_uspace);
  67.    
  68.     if (!KERNEL_ADDRESS_SPACE_SHADOWED) {
  69.         if (overlaps((uintptr_t) uspace_src, size,
  70.             KERNEL_ADDRESS_SPACE_START, KERNEL_ADDRESS_SPACE_END-KERNEL_ADDRESS_SPACE_START)) {
  71.             /*
  72.              * The userspace source block conflicts with kernel address space.
  73.              */
  74.             return EPERM;
  75.         }
  76.     }
  77.    
  78.     ipl = interrupts_disable();
  79.     THREAD->in_copy_from_uspace = true;
  80.    
  81.     rc = memcpy_from_uspace(dst, uspace_src, size);
  82.  
  83.     THREAD->in_copy_from_uspace = false;
  84.  
  85.     interrupts_restore(ipl);
  86.     return !rc ? EPERM : 0;
  87. }
  88.  
  89. /** Copy data from kernel to userspace.
  90.  *
  91.  * Provisions are made to return value even after page fault.
  92.  *
  93.  * This function can be called only from syscall.
  94.  *
  95.  * @param uspace_dst Destination userspace address.
  96.  * @param src Source kernel address.
  97.  * @param size Size of the data to be copied.
  98.  *
  99.  * @return 0 on success or error code from @ref errno.h.
  100.  */
  101. int copy_to_uspace(void *uspace_dst, const void *src, size_t size)
  102. {
  103.     ipl_t ipl;
  104.     int rc;
  105.    
  106.     ASSERT(THREAD);
  107.     ASSERT(!THREAD->in_copy_to_uspace);
  108.    
  109.     if (!KERNEL_ADDRESS_SPACE_SHADOWED) {
  110.         if (overlaps((uintptr_t) uspace_dst, size,
  111.             KERNEL_ADDRESS_SPACE_START, KERNEL_ADDRESS_SPACE_END-KERNEL_ADDRESS_SPACE_START)) {
  112.             /*
  113.              * The userspace destination block conflicts with kernel address space.
  114.              */
  115.             return EPERM;
  116.         }
  117.     }
  118.    
  119.     ipl = interrupts_disable();
  120.     THREAD->in_copy_to_uspace = true;
  121.    
  122.     rc = memcpy_to_uspace(uspace_dst, src, size);
  123.  
  124.     THREAD->in_copy_to_uspace = false;
  125.  
  126.     interrupts_restore(ipl);
  127.     return !rc ? EPERM : 0;
  128. }
  129.  
  130. /** @}
  131.  */
  132.