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  1. /*
  2.  * Copyright (C) 2001-2004 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. /**
  30.  * @file    tlb.c
  31.  * @brief   Generic TLB shootdown algorithm.
  32.  *
  33.  * The algorithm implemented here is based on the CMU TLB shootdown
  34.  * algorithm and is further simplified (e.g. all CPUs receive all TLB
  35.  * shootdown messages).
  36.  */
  37.  
  38. #include <mm/tlb.h>
  39. #include <mm/asid.h>
  40. #include <arch/mm/tlb.h>
  41. #include <smp/ipi.h>
  42. #include <synch/spinlock.h>
  43. #include <typedefs.h>
  44. #include <atomic.h>
  45. #include <arch/interrupt.h>
  46. #include <config.h>
  47. #include <arch.h>
  48. #include <panic.h>
  49. #include <debug.h>
  50.  
  51. /**
  52.  * This lock is used for synchronisation between sender and
  53.  * recipients of TLB shootdown message. It must be acquired
  54.  * before CPU structure lock.
  55.  */
  56. SPINLOCK_INITIALIZE(tlblock);
  57.  
  58. void tlb_init(void)
  59. {
  60.     tlb_arch_init();
  61. }
  62.  
  63. #ifdef CONFIG_SMP
  64.  
  65. /** Send TLB shootdown message.
  66.  *
  67.  * This function attempts to deliver TLB shootdown message
  68.  * to all other processors.
  69.  *
  70.  * This function must be called with interrupts disabled.
  71.  *
  72.  * @param type Type describing scope of shootdown.
  73.  * @param asid Address space, if required by type.
  74.  * @param page Virtual page address, if required by type.
  75.  * @param count Number of pages, if required by type.
  76.  */
  77. void tlb_shootdown_start(tlb_invalidate_type_t type, asid_t asid, __address page, count_t count)
  78. {
  79.     int i;
  80.  
  81.     CPU->tlb_active = 0;
  82.     spinlock_lock(&tlblock);
  83.    
  84.     for (i = 0; i < config.cpu_count; i++) {
  85.         cpu_t *cpu;
  86.        
  87.         if (i == CPU->id)
  88.             continue;
  89.  
  90.         cpu = &cpus[i];
  91.         spinlock_lock(&cpu->lock);
  92.         if (cpu->tlb_messages_count == TLB_MESSAGE_QUEUE_LEN) {
  93.             /*
  94.              * The message queue is full.
  95.              * Erase the queue and store one TLB_INVL_ALL message.
  96.              */
  97.             cpu->tlb_messages_count = 1;
  98.             cpu->tlb_messages[0].type = TLB_INVL_ALL;
  99.             cpu->tlb_messages[0].asid = ASID_INVALID;
  100.             cpu->tlb_messages[0].page = 0;
  101.             cpu->tlb_messages[0].count = 0;
  102.         } else {
  103.             /*
  104.              * Enqueue the message.
  105.              */
  106.             cpu->tlb_messages[cpu->tlb_messages_count].type = type;
  107.             cpu->tlb_messages[cpu->tlb_messages_count].asid = asid;
  108.             cpu->tlb_messages[cpu->tlb_messages_count].page = page;
  109.             cpu->tlb_messages[cpu->tlb_messages_count].count = count;
  110.             cpu->tlb_messages_count++;
  111.         }
  112.         spinlock_unlock(&cpu->lock);
  113.     }
  114.    
  115.     tlb_shootdown_ipi_send();
  116.  
  117. busy_wait: 
  118.     for (i = 0; i < config.cpu_count; i++)
  119.         if (cpus[i].tlb_active)
  120.             goto busy_wait;
  121. }
  122.  
  123. /** Finish TLB shootdown sequence. */
  124. void tlb_shootdown_finalize(void)
  125. {
  126.     spinlock_unlock(&tlblock);
  127.     CPU->tlb_active = 1;
  128. }
  129.  
  130. void tlb_shootdown_ipi_send(void)
  131. {
  132.     ipi_broadcast(VECTOR_TLB_SHOOTDOWN_IPI);
  133. }
  134.  
  135. /** Receive TLB shootdown message. */
  136. void tlb_shootdown_ipi_recv(void)
  137. {
  138.     tlb_invalidate_type_t type;
  139.     asid_t asid;
  140.     __address page;
  141.     count_t count;
  142.     int i;
  143.    
  144.     ASSERT(CPU);
  145.    
  146.     CPU->tlb_active = 0;
  147.     spinlock_lock(&tlblock);
  148.     spinlock_unlock(&tlblock);
  149.    
  150.     spinlock_lock(&CPU->lock);
  151.     ASSERT(CPU->tlb_messages_count <= TLB_MESSAGE_QUEUE_LEN);
  152.  
  153.     for (i = 0; i < CPU->tlb_messages_count; CPU->tlb_messages_count--) {
  154.         type = CPU->tlb_messages[i].type;
  155.         asid = CPU->tlb_messages[i].asid;
  156.         page = CPU->tlb_messages[i].page;
  157.         count = CPU->tlb_messages[i].count;
  158.  
  159.         switch (type) {
  160.             case TLB_INVL_ALL:
  161.             tlb_invalidate_all();
  162.             break;
  163.             case TLB_INVL_ASID:
  164.             tlb_invalidate_asid(asid);
  165.             break;
  166.             case TLB_INVL_PAGES:
  167.                 ASSERT(count);
  168.             tlb_invalidate_pages(asid, page, count);
  169.             break;
  170.             default:
  171.             panic("unknown type (%d)\n", type);
  172.             break;
  173.         }
  174.         if (type == TLB_INVL_ALL)
  175.             break;
  176.     }
  177.    
  178.     spinlock_unlock(&CPU->lock);
  179.     CPU->tlb_active = 1;
  180. }
  181.  
  182. #endif /* CONFIG_SMP */
  183.