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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 <arch/mm/tlb.h>
  45. #include <smp/ipi.h>
  46. #include <synch/spinlock.h>
  47. #include <atomic.h>
  48. #include <arch/interrupt.h>
  49. #include <config.h>
  50. #include <arch.h>
  51. #include <panic.h>
  52. #include <debug.h>
  53. #include <cpu.h>
  54.  
  55. /**
  56.  * This lock is used for synchronisation between sender and
  57.  * recipients of TLB shootdown message. It must be acquired
  58.  * before CPU structure lock.
  59.  */
  60. SPINLOCK_INITIALIZE(tlblock);
  61.  
  62. void tlb_init(void)
  63. {
  64.     tlb_arch_init();
  65. }
  66.  
  67. #ifdef CONFIG_SMP
  68.  
  69. /** Send TLB shootdown message.
  70.  *
  71.  * This function attempts to deliver TLB shootdown message
  72.  * to all other processors.
  73.  *
  74.  * This function must be called with interrupts disabled.
  75.  *
  76.  * @param type Type describing scope of shootdown.
  77.  * @param asid Address space, if required by type.
  78.  * @param page Virtual page address, if required by type.
  79.  * @param count Number of pages, if required by type.
  80.  */
  81. void tlb_shootdown_start(tlb_invalidate_type_t type, asid_t asid,
  82.     uintptr_t page, count_t count)
  83. {
  84.     unsigned int i;
  85.  
  86.     CPU->tlb_active = 0;
  87.     spinlock_lock(&tlblock);
  88.    
  89.     for (i = 0; i < config.cpu_count; i++) {
  90.         cpu_t *cpu;
  91.        
  92.         if (i == CPU->id)
  93.             continue;
  94.  
  95.         cpu = &cpus[i];
  96.         spinlock_lock(&cpu->lock);
  97.         if (cpu->tlb_messages_count == TLB_MESSAGE_QUEUE_LEN) {
  98.             /*
  99.              * The message queue is full.
  100.              * Erase the queue and store one TLB_INVL_ALL message.
  101.              */
  102.             cpu->tlb_messages_count = 1;
  103.             cpu->tlb_messages[0].type = TLB_INVL_ALL;
  104.             cpu->tlb_messages[0].asid = ASID_INVALID;
  105.             cpu->tlb_messages[0].page = 0;
  106.             cpu->tlb_messages[0].count = 0;
  107.         } else {
  108.             /*
  109.              * Enqueue the message.
  110.              */
  111.             index_t idx = cpu->tlb_messages_count++;
  112.             cpu->tlb_messages[idx].type = type;
  113.             cpu->tlb_messages[idx].asid = asid;
  114.             cpu->tlb_messages[idx].page = page;
  115.             cpu->tlb_messages[idx].count = count;
  116.         }
  117.         spinlock_unlock(&cpu->lock);
  118.     }
  119.    
  120.     tlb_shootdown_ipi_send();
  121.  
  122. busy_wait: 
  123.     for (i = 0; i < config.cpu_count; i++)
  124.         if (cpus[i].tlb_active)
  125.             goto busy_wait;
  126. }
  127.  
  128. /** Finish TLB shootdown sequence. */
  129. void tlb_shootdown_finalize(void)
  130. {
  131.     spinlock_unlock(&tlblock);
  132.     CPU->tlb_active = 1;
  133. }
  134.  
  135. void tlb_shootdown_ipi_send(void)
  136. {
  137.     ipi_broadcast(VECTOR_TLB_SHOOTDOWN_IPI);
  138. }
  139.  
  140. /** Receive TLB shootdown message. */
  141. void tlb_shootdown_ipi_recv(void)
  142. {
  143.     tlb_invalidate_type_t type;
  144.     asid_t asid;
  145.     uintptr_t page;
  146.     count_t count;
  147.     unsigned int i;
  148.    
  149.     ASSERT(CPU);
  150.    
  151.     CPU->tlb_active = 0;
  152.     spinlock_lock(&tlblock);
  153.     spinlock_unlock(&tlblock);
  154.    
  155.     spinlock_lock(&CPU->lock);
  156.     ASSERT(CPU->tlb_messages_count <= TLB_MESSAGE_QUEUE_LEN);
  157.  
  158.     for (i = 0; i < CPU->tlb_messages_count; CPU->tlb_messages_count--) {
  159.         type = CPU->tlb_messages[i].type;
  160.         asid = CPU->tlb_messages[i].asid;
  161.         page = CPU->tlb_messages[i].page;
  162.         count = CPU->tlb_messages[i].count;
  163.  
  164.         switch (type) {
  165.         case TLB_INVL_ALL:
  166.             tlb_invalidate_all();
  167.             break;
  168.         case TLB_INVL_ASID:
  169.             tlb_invalidate_asid(asid);
  170.             break;
  171.         case TLB_INVL_PAGES:
  172.                 ASSERT(count);
  173.             tlb_invalidate_pages(asid, page, count);
  174.             break;
  175.         default:
  176.             panic("unknown type (%d)\n", type);
  177.             break;
  178.         }
  179.         if (type == TLB_INVL_ALL)
  180.             break;
  181.     }
  182.    
  183.     spinlock_unlock(&CPU->lock);
  184.     CPU->tlb_active = 1;
  185. }
  186.  
  187. #endif /* CONFIG_SMP */
  188.  
  189. /** @}
  190.  */
  191.