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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 <proc/scheduler.h>
  30. #include <cpu.h>
  31. #include <proc/task.h>
  32. #include <proc/thread.h>
  33. #include <arch.h>
  34. #include <arch/context.h>   /* SP_DELTA */
  35. #include <arch/debugger.h>
  36. #include <arch/pm.h>
  37. #include <arch/asm.h>
  38.  
  39. /** Perform ia32 specific tasks needed before the new task is run. */
  40. void before_task_runs_arch(void)
  41. {
  42. }
  43.  
  44. /** Perform ia32 specific tasks needed before the new thread is scheduled.
  45.  *
  46.  * THREAD is locked and interrupts are disabled.
  47.  */
  48. void before_thread_runs_arch(void)
  49. {
  50.     size_t iomap_size;
  51.     ptr_16_32_t cpugdtr;
  52.     descriptor_t *gdt_p;
  53.  
  54.     CPU->arch.tss->esp0 = (__address) &THREAD->kstack[THREAD_STACK_SIZE-SP_DELTA];
  55.     CPU->arch.tss->ss0 = selector(KDATA_DES);
  56.  
  57.     /* Set up TLS in GS register */
  58.     set_tls_desc(THREAD->arch.tls);
  59.  
  60.     /*
  61.      * Switch the I/O Permission Bitmap, if necessary.
  62.      *
  63.      * First, copy the I/O Permission Bitmap.
  64.      * This needs to be changed so that the
  65.      * copying is avoided if the same task
  66.      * was already running and the iomap did
  67.      * not change.
  68.      */
  69.     spinlock_lock(&TASK->lock);
  70.     iomap_size = TASK->arch.iomap_size;
  71.     if (iomap_size) {
  72.         ASSERT(TASK->arch.iomap);
  73.         memcpy(CPU->arch.tss->iomap, TASK->arch.iomap, iomap_size);
  74.         CPU->arch.tss->iomap[iomap_size] = 0xff;    /* terminating byte */
  75.     }
  76.     spinlock_unlock(&TASK->lock);  
  77.  
  78.     /* Second, adjust TSS segment limit. */
  79.     gdtr_store(&cpugdtr);
  80.     gdt_p = (descriptor_t *) cpugdtr.base;
  81.     gdt_setlimit(&gdt_p[TSS_DES], TSS_BASIC_SIZE + iomap_size - 1);
  82.     gdtr_load(&cpugdtr);
  83.  
  84. #ifdef CONFIG_DEBUG_AS_WATCHPOINT
  85.     /* Set watchpoint on AS to ensure that nobody sets it to zero */
  86.     if (CPU->id < BKPOINTS_MAX)
  87.         breakpoint_add(&((the_t *) THREAD->kstack)->as,
  88.                    BKPOINT_WRITE | BKPOINT_CHECK_ZERO,
  89.                    CPU->id);
  90. #endif
  91. }
  92.  
  93. void after_thread_ran_arch(void)
  94. {
  95. }
  96.