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  1. /*
  2.  * Copyright (c) 2005 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 ia32xen
  30.  * @{
  31.  */
  32. /** @file
  33.  */
  34.  
  35. #include <userspace.h>
  36. #include <arch/pm.h>
  37. #include <arch/types.h>
  38. #include <arch.h>
  39. #include <proc/uarg.h>
  40. #include <mm/as.h>
  41.  
  42.  
  43. /** Enter userspace
  44.  *
  45.  * Change CPU protection level to 3, enter userspace.
  46.  *
  47.  */
  48. void userspace(uspace_arg_t *kernel_uarg)
  49. {
  50.     uint32_t ipl = interrupts_disable();
  51.  
  52.     asm volatile (
  53.         /*
  54.          * Clear nested task flag.
  55.          */
  56.         "pushfl\n"
  57.         "pop %%eax\n"
  58.         "and $0xffffbfff, %%eax\n"
  59.         "push %%eax\n"
  60.         "popfl\n"
  61.  
  62.         /* Set up GS register (TLS) */
  63.         "movl %6, %%gs\n"
  64.  
  65.         "pushl %0\n"
  66.         "pushl %1\n"
  67.         "pushl %2\n"
  68.         "pushl %3\n"
  69.         "pushl %4\n"
  70.         "movl %5, %%eax\n"
  71.         "iret\n"
  72.         :
  73.         : "i" (selector(UDATA_DES) | PL_USER),
  74.           "r" (kernel_uarg->uspace_stack + THREAD_STACK_SIZE),
  75.           "r" (ipl),
  76.           "i" (selector(UTEXT_DES) | PL_USER),
  77.           "r" (kernel_uarg->uspace_entry),
  78.           "r" (kernel_uarg->uspace_uarg),
  79.           "r" (selector(TLS_DES))
  80.         : "eax"
  81.     );
  82.    
  83.     /* Unreachable */
  84.     for(;;)
  85.         ;
  86. }
  87.  
  88. /** @}
  89.  */
  90.