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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/frame.h>
  33. #include <mm/page.h>
  34. #include <mm/as.h>
  35. #include <arch.h>
  36. #include <print.h>
  37. #include <symtab.h>
  38.  
  39.  
  40. static phte_t *phte;
  41.  
  42.  
  43. /** Initialize Page Hash Table.
  44.  *
  45.  * Setup the Page Hash Table with no entries.
  46.  *
  47.  */
  48. void tlb_arch_init(void)
  49. {
  50.     phte_t *physical_phte = (phte_t *) PFN2ADDR(frame_alloc(PHT_ORDER, FRAME_KA | FRAME_PANIC));
  51.     phte =(phte_t *) PA2KA((__address) physical_phte);
  52.    
  53.     ASSERT((__address) physical_phte % (1 << PHT_BITS) == 0);
  54.    
  55.     memsetb((__address) phte, 1 << PHT_BITS, 0);
  56.    
  57.     asm volatile (
  58.         "mtsdr1 %0\n"
  59.         :
  60.         : "r" ((__address) physical_phte)
  61.     );
  62. }
  63.  
  64.  
  65. /** Try to find PTE for faulting address
  66.  *
  67.  * Try to find PTE for faulting address.
  68.  * The AS->lock must be held on entry to this function.
  69.  *
  70.  * @param badvaddr Faulting virtual address.
  71.  * @return         PTE on success, NULL otherwise.
  72.  *
  73.  */
  74. static pte_t *find_mapping_and_check(__address badvaddr)
  75. {
  76.     /*
  77.      * Check if the mapping exists in page tables.
  78.      */
  79.     pte_t *pte = page_mapping_find(AS, badvaddr);
  80.     if ((pte) && (pte->p)) {
  81.         /*
  82.          * Mapping found in page tables.
  83.          * Immediately succeed.
  84.          */
  85.         return pte;
  86.     } else {
  87.         /*
  88.          * Mapping not found in page tables.
  89.          * Resort to higher-level page fault handler.
  90.          */
  91.         page_table_unlock(AS, true);
  92.         if (as_page_fault(badvaddr)) {
  93.             /*
  94.              * The higher-level page fault handler succeeded,
  95.              * The mapping ought to be in place.
  96.              */
  97.             page_table_lock(AS, true);
  98.             pte = page_mapping_find(AS, badvaddr);
  99.             ASSERT((pte) && (pte->p));
  100.             return pte;
  101.         } else {
  102.             page_table_lock(AS, true);
  103.             printf("Page fault.\n");
  104.             return NULL;
  105.         }
  106.        
  107.     }
  108. }
  109.  
  110.  
  111. static void pht_refill_fail(__address badvaddr, istate_t *istate)
  112. {
  113.     char *symbol = "";
  114.     char *sym2 = "";
  115.  
  116.     char *s = get_symtab_entry(istate->pc);
  117.     if (s)
  118.         symbol = s;
  119.     s = get_symtab_entry(istate->lr);
  120.     if (s)
  121.         sym2 = s;
  122.     panic("%p: PHT Refill Exception at %p (%s<-%s)\n", badvaddr, istate->pc, symbol, sym2);
  123. }
  124.  
  125.  
  126. /** Process Instruction/Data Storage Interrupt
  127.  *
  128.  * @param data   True if Data Storage Interrupt.
  129.  * @param istate Interrupted register context.
  130.  *
  131.  */
  132. void pht_refill(bool data, istate_t *istate)
  133. {
  134.     asid_t asid;
  135.     __address badvaddr;
  136.     pte_t *pte;
  137.     __u32 page;
  138.     __u32 api;
  139.     __u32 vsid;
  140.     __u32 hash;
  141.     __u32 i;
  142.    
  143.     if (data) {
  144.         asm volatile (
  145.             "mfdar %0\n"
  146.             : "=r" (badvaddr)
  147.         );
  148.     } else
  149.         badvaddr = istate->pc;
  150.        
  151.     spinlock_lock(&AS->lock);
  152.     asid = AS->asid;
  153.     spinlock_unlock(&AS->lock);
  154.    
  155.     page_table_lock(AS, true);
  156.    
  157.     pte = find_mapping_and_check(badvaddr);
  158.     if (!pte)
  159.         goto fail;
  160.  
  161.     /* Record access to PTE */
  162.     pte->a = 1;
  163.    
  164.     page = (badvaddr >> 12) & 0xffff;
  165.     api = (badvaddr >> 22) & 0x3f;
  166.     asm volatile (
  167.         "mfsrin %0, %1\n"
  168.         : "=r" (vsid)
  169.         : "r" (badvaddr)
  170.     );
  171.    
  172.     /* Primary hash (xor) */
  173.     hash = ((vsid ^ page) & 0x3ff) << 3;
  174.    
  175.     /* Find invalid PTE in PTEG */
  176.     for (i = 0; i < 8; i++) {
  177.         if (!phte[hash + i].v)
  178.             break;
  179.     }
  180.    
  181.     // TODO: Check access/change bits, secondary hash
  182.    
  183.     if (i == 8)
  184.         i = page % 8;
  185.    
  186.     phte[hash + i].v = 1;
  187.     phte[hash + i].vsid = vsid;
  188.     phte[hash + i].h = 0;
  189.     phte[hash + i].api = api;
  190.     phte[hash + i].rpn = pte->pfn;
  191.     phte[hash + i].r = 0;
  192.     phte[hash + i].c = 0;
  193.     phte[hash + i].pp = 2; // FIXME
  194.    
  195.     page_table_unlock(AS, true);
  196.     return;
  197.    
  198. fail:
  199.     page_table_unlock(AS, true);
  200.     pht_refill_fail(badvaddr, istate);
  201. }
  202.  
  203.  
  204. /** Print contents of Page Hash Table. */
  205. void tlb_print(void)
  206. {
  207. }
  208.