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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. /** @addtogroup genericmm
  30.  * @{
  31.  */
  32.  
  33. /**
  34.  * @file
  35.  * @brief   Generic TLB shootdown algorithm.
  36.  *
  37.  * The algorithm implemented here is based on the CMU TLB shootdown
  38.  * algorithm and is further simplified (e.g. all CPUs receive all TLB
  39.  * shootdown messages).
  40.  */
  41.  
  42. #include <mm/tlb.h>
  43. #include <mm/asid.h>
  44. #include <smp/ipi.h>
  45. #include <synch/spinlock.h>
  46. #include <atomic.h>
  47. #include <arch/interrupt.h>
  48. #include <config.h>
  49. #include <arch.h>
  50. #include <panic.h>
  51. #include <debug.h>
  52. #include <cpu.h>
  53.  
  54. /**
  55.  * This lock is used for synchronisation between sender and
  56.  * recipients of TLB shootdown message. It must be acquired
  57.  * before CPU structure lock.
  58.  */
  59. SPINLOCK_INITIALIZE(tlblock);
  60.  
  61. void tlb_init(void)
  62. {
  63.     tlb_arch_init();
  64. }
  65.  
  66. #ifdef CONFIG_SMP
  67.  
  68. /** Send TLB shootdown message.
  69.  *
  70.  * This function attempts to deliver TLB shootdown message
  71.  * to all other processors.
  72.  *
  73.  * This function must be called with interrupts disabled.
  74.  *
  75.  * @param type Type describing scope of shootdown.
  76.  * @param asid Address space, if required by type.
  77.  * @param page Virtual page address, if required by type.
  78.  * @param count Number of pages, if required by type.
  79.  */
  80. void tlb_shootdown_start(tlb_invalidate_type_t type, asid_t asid,
  81.     uintptr_t page, count_t count)
  82. {
  83.     unsigned int i;
  84.  
  85.     CPU->tlb_active = 0;
  86.     spinlock_lock(&tlblock);
  87.    
  88.     for (i = 0; i < config.cpu_count; i++) {
  89.         cpu_t *cpu;
  90.        
  91.         if (i == CPU->id)
  92.             continue;
  93.  
  94.         cpu = &cpus[i];
  95.         spinlock_lock(&cpu->lock);
  96.         if (cpu->tlb_messages_count == TLB_MESSAGE_QUEUE_LEN) {
  97.             /*
  98.              * The message queue is full.
  99.              * Erase the queue and store one TLB_INVL_ALL message.
  100.              */
  101.             cpu->tlb_messages_count = 1;
  102.             cpu->tlb_messages[0].type = TLB_INVL_ALL;
  103.             cpu->tlb_messages[0].asid = ASID_INVALID;
  104.             cpu->tlb_messages[0].page = 0;
  105.             cpu->tlb_messages[0].count = 0;
  106.         } else {
  107.             /*
  108.              * Enqueue the message.
  109.              */
  110.             index_t idx = cpu->tlb_messages_count++;
  111.             cpu->tlb_messages[idx].type = type;
  112.             cpu->tlb_messages[idx].asid = asid;
  113.             cpu->tlb_messages[idx].page = page;
  114.             cpu->tlb_messages[idx].count = count;
  115.         }
  116.         spinlock_unlock(&cpu->lock);
  117.     }
  118.    
  119.     tlb_shootdown_ipi_send();
  120.  
  121. busy_wait: 
  122.     for (i = 0; i < config.cpu_count; i++)
  123.         if (cpus[i].tlb_active)
  124.             goto busy_wait;
  125. }
  126.  
  127. /** Finish TLB shootdown sequence. */
  128. void tlb_shootdown_finalize(void)
  129. {
  130.     spinlock_unlock(&tlblock);
  131.     CPU->tlb_active = 1;
  132. }
  133.  
  134. void tlb_shootdown_ipi_send(void)
  135. {
  136.     ipi_broadcast(VECTOR_TLB_SHOOTDOWN_IPI);
  137. }
  138.  
  139. /** Receive TLB shootdown message. */
  140. void tlb_shootdown_ipi_recv(void)
  141. {
  142.     tlb_invalidate_type_t type;
  143.     asid_t asid;
  144.     uintptr_t page;
  145.     count_t count;
  146.     unsigned int i;
  147.    
  148.     ASSERT(CPU);
  149.    
  150.     CPU->tlb_active = 0;
  151.     spinlock_lock(&tlblock);
  152.     spinlock_unlock(&tlblock);
  153.    
  154.     spinlock_lock(&CPU->lock);
  155.     ASSERT(CPU->tlb_messages_count <= TLB_MESSAGE_QUEUE_LEN);
  156.  
  157.     for (i = 0; i < CPU->tlb_messages_count; CPU->tlb_messages_count--) {
  158.         type = CPU->tlb_messages[i].type;
  159.         asid = CPU->tlb_messages[i].asid;
  160.         page = CPU->tlb_messages[i].page;
  161.         count = CPU->tlb_messages[i].count;
  162.  
  163.         switch (type) {
  164.         case TLB_INVL_ALL:
  165.             tlb_invalidate_all();
  166.             break;
  167.         case TLB_INVL_ASID:
  168.             tlb_invalidate_asid(asid);
  169.             break;
  170.         case TLB_INVL_PAGES:
  171.                 ASSERT(count);
  172.             tlb_invalidate_pages(asid, page, count);
  173.             break;
  174.         default:
  175.             panic("unknown type (%d)\n", type);
  176.             break;
  177.         }
  178.         if (type == TLB_INVL_ALL)
  179.             break;
  180.     }
  181.    
  182.     spinlock_unlock(&CPU->lock);
  183.     CPU->tlb_active = 1;
  184. }
  185.  
  186. #endif /* CONFIG_SMP */
  187.  
  188. /** @}
  189.  */
  190.