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