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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. #include <typedefs.h>
  48.  
  49. /** Copy data from userspace to kernel.
  50.  *
  51.  * Provisions are made to return value even after page fault.
  52.  *
  53.  * This function can be called only from syscall.
  54.  *
  55.  * @param dst Destination kernel address.
  56.  * @param uspace_src Source userspace address.
  57.  * @param size Size of the data to be copied.
  58.  *
  59.  * @return 0 on success or error code from @ref errno.h.
  60.  */
  61. int copy_from_uspace(void *dst, const void *uspace_src, size_t size)
  62. {
  63.     ipl_t ipl;
  64.     int rc;
  65.    
  66.     ASSERT(THREAD);
  67.     ASSERT(!THREAD->in_copy_from_uspace);
  68.    
  69.     if (!KERNEL_ADDRESS_SPACE_SHADOWED) {
  70.         if (overlaps((uintptr_t) uspace_src, size,
  71.             KERNEL_ADDRESS_SPACE_START, KERNEL_ADDRESS_SPACE_END-KERNEL_ADDRESS_SPACE_START)) {
  72.             /*
  73.              * The userspace source block conflicts with kernel address space.
  74.              */
  75.             return EPERM;
  76.         }
  77.     }
  78.    
  79.     ipl = interrupts_disable();
  80.     THREAD->in_copy_from_uspace = true;
  81.    
  82.     rc = memcpy_from_uspace(dst, uspace_src, size);
  83.  
  84.     THREAD->in_copy_from_uspace = false;
  85.  
  86.     interrupts_restore(ipl);
  87.     return !rc ? EPERM : 0;
  88. }
  89.  
  90. /** Copy data from kernel to userspace.
  91.  *
  92.  * Provisions are made to return value even after page fault.
  93.  *
  94.  * This function can be called only from syscall.
  95.  *
  96.  * @param uspace_dst Destination userspace address.
  97.  * @param src Source kernel address.
  98.  * @param size Size of the data to be copied.
  99.  *
  100.  * @return 0 on success or error code from @ref errno.h.
  101.  */
  102. int copy_to_uspace(void *uspace_dst, const void *src, size_t size)
  103. {
  104.     ipl_t ipl;
  105.     int rc;
  106.    
  107.     ASSERT(THREAD);
  108.     ASSERT(!THREAD->in_copy_to_uspace);
  109.    
  110.     if (!KERNEL_ADDRESS_SPACE_SHADOWED) {
  111.         if (overlaps((uintptr_t) uspace_dst, size,
  112.             KERNEL_ADDRESS_SPACE_START, KERNEL_ADDRESS_SPACE_END-KERNEL_ADDRESS_SPACE_START)) {
  113.             /*
  114.              * The userspace destination block conflicts with kernel address space.
  115.              */
  116.             return EPERM;
  117.         }
  118.     }
  119.    
  120.     ipl = interrupts_disable();
  121.     THREAD->in_copy_to_uspace = true;
  122.    
  123.     rc = memcpy_to_uspace(uspace_dst, src, size);
  124.  
  125.     THREAD->in_copy_to_uspace = false;
  126.  
  127.     interrupts_restore(ipl);
  128.     return !rc ? EPERM : 0;
  129. }
  130.  
  131. /** @}
  132.  */
  133.