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  1. /*
  2.  * Copyright (C) 2006 Martin Decky
  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 <arch/mm/tlb.h>
  30. #include <arch/types.h>
  31. #include <mm/tlb.h>
  32. #include <mm/page.h>
  33. #include <mm/as.h>
  34. #include <arch.h>
  35. #include <print.h>
  36. #include <symtab.h>
  37.  
  38.  
  39. /** Initialize Page Hash Table.
  40.  *
  41.  * Setup the Page Hash Table with no entries.
  42.  *
  43.  */
  44. void tlb_arch_init(void)
  45. {
  46. }
  47.  
  48.  
  49. /** Try to find PTE for faulting address
  50.  *
  51.  * Try to find PTE for faulting address.
  52.  * The AS->lock must be held on entry to this function.
  53.  *
  54.  * @param badvaddr Faulting virtual address.
  55.  * @return         PTE on success, NULL otherwise.
  56.  *
  57.  */
  58. static pte_t *find_mapping_and_check(__address badvaddr)
  59. {
  60.     /*
  61.      * Check if the mapping exists in page tables.
  62.      */
  63.     pte_t *pte = page_mapping_find(AS, badvaddr);
  64.     if ((pte) && (pte->p)) {
  65.         /*
  66.          * Mapping found in page tables.
  67.          * Immediately succeed.
  68.          */
  69.         return pte;
  70.     } else {
  71.         /*
  72.          * Mapping not found in page tables.
  73.          * Resort to higher-level page fault handler.
  74.          */
  75.         page_table_unlock(AS, true);
  76.         if (as_page_fault(badvaddr)) {
  77.             /*
  78.              * The higher-level page fault handler succeeded,
  79.              * The mapping ought to be in place.
  80.              */
  81.             page_table_lock(AS, true);
  82.             pte = page_mapping_find(AS, badvaddr);
  83.             ASSERT((pte) && (pte->p));
  84.             return pte;
  85.         } else {
  86.             page_table_lock(AS, true);
  87.             printf("Page fault.\n");
  88.             return NULL;
  89.         }
  90.        
  91.     }
  92. }
  93.  
  94.  
  95. static void pht_refill_fail(__address badvaddr, istate_t *istate)
  96. {
  97.     char *symbol = "";
  98.     char *sym2 = "";
  99.  
  100.     char *s = get_symtab_entry(istate->pc);
  101.     if (s)
  102.         symbol = s;
  103.     s = get_symtab_entry(istate->lr);
  104.     if (s)
  105.         sym2 = s;
  106.     panic("%X: PHT Refill Exception at %X(%s<-%s)\n", badvaddr, istate->pc, symbol, sym2);
  107. }
  108.  
  109.  
  110. /** Process Data Storage Interrupt
  111.  *
  112.  * @param istate Interrupted register context.
  113.  *
  114.  */
  115. void pht_refill(istate_t *istate)
  116. {
  117.     asid_t asid;
  118.     __address badvaddr;
  119.     pte_t *pte;
  120.    
  121.     __asm__ volatile (
  122.         "mfdar %0\n"
  123.         : "=r" (badvaddr)
  124.     );
  125.    
  126.     spinlock_lock(&AS->lock);
  127.     asid = AS->asid;
  128.     spinlock_unlock(&AS->lock);
  129.    
  130.     page_table_lock(AS, true);
  131.    
  132.     pte = find_mapping_and_check(badvaddr);
  133.     if (!pte)
  134.         goto fail;
  135.  
  136.     /*
  137.      * Record access to PTE.
  138.      */
  139.     pte->a = 1;
  140.    
  141.     // FIXME: Insert entry into PHT
  142.  
  143.     page_table_unlock(AS, true);
  144.     return;
  145.    
  146. fail:
  147.     page_table_unlock(AS, true);
  148.     pht_refill_fail(badvaddr, istate);
  149. }
  150.  
  151.  
  152. /** Print contents of Page Hash Table. */
  153. void tlb_print(void)
  154. {
  155. }
  156.