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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.  * @param istate Pointer to interrupted state.
  72.  * @param pfrc Pointer to variable where as_page_fault() return code will be stored.
  73.  * @return         PTE on success, NULL otherwise.
  74.  *
  75.  */
  76. static pte_t *find_mapping_and_check(__address badvaddr, istate_t *istate, int *pfcr)
  77. {
  78.     /*
  79.      * Check if the mapping exists in page tables.
  80.      */
  81.     pte_t *pte = page_mapping_find(AS, badvaddr);
  82.     if ((pte) && (pte->p)) {
  83.         /*
  84.          * Mapping found in page tables.
  85.          * Immediately succeed.
  86.          */
  87.         return pte;
  88.     } else {
  89.         int rc;
  90.    
  91.         /*
  92.          * Mapping not found in page tables.
  93.          * Resort to higher-level page fault handler.
  94.          */
  95.         page_table_unlock(AS, true);
  96.         switch (rc = as_page_fault(badvaddr, istate)) {
  97.         case AS_PF_OK:
  98.             /*
  99.              * The higher-level page fault handler succeeded,
  100.              * The mapping ought to be in place.
  101.              */
  102.             page_table_lock(AS, true);
  103.             pte = page_mapping_find(AS, badvaddr);
  104.             ASSERT((pte) && (pte->p));
  105.             return pte;
  106.             break;
  107.         case AS_PF_DEFER:
  108.             page_table_lock(AS, true);
  109.             *pfcr = rc;
  110.             return NULL;
  111.             break;
  112.         case AS_PF_FAULT:
  113.             page_table_lock(AS, true);
  114.             printf("Page fault.\n");
  115.             *pfcr = rc;
  116.             return NULL;
  117.             break;
  118.         default:
  119.             panic("unexpected rc (%d)\n", rc);
  120.             break;
  121.         }  
  122.     }
  123. }
  124.  
  125.  
  126. static void pht_refill_fail(__address badvaddr, istate_t *istate)
  127. {
  128.     char *symbol = "";
  129.     char *sym2 = "";
  130.  
  131.     char *s = get_symtab_entry(istate->pc);
  132.     if (s)
  133.         symbol = s;
  134.     s = get_symtab_entry(istate->lr);
  135.     if (s)
  136.         sym2 = s;
  137.     panic("%p: PHT Refill Exception at %p (%s<-%s)\n", badvaddr, istate->pc, symbol, sym2);
  138. }
  139.  
  140.  
  141. /** Process Instruction/Data Storage Interrupt
  142.  *
  143.  * @param data   True if Data Storage Interrupt.
  144.  * @param istate Interrupted register context.
  145.  *
  146.  */
  147. void pht_refill(bool data, istate_t *istate)
  148. {
  149.     asid_t asid;
  150.     __address badvaddr;
  151.     pte_t *pte;
  152.     __u32 page;
  153.     __u32 api;
  154.     __u32 vsid;
  155.     __u32 hash;
  156.     __u32 i;
  157.     int pfcr;
  158.    
  159.     if (data) {
  160.         asm volatile (
  161.             "mfdar %0\n"
  162.             : "=r" (badvaddr)
  163.         );
  164.     } else
  165.         badvaddr = istate->pc;
  166.        
  167.     spinlock_lock(&AS->lock);
  168.     asid = AS->asid;
  169.     spinlock_unlock(&AS->lock);
  170.    
  171.     page_table_lock(AS, true);
  172.    
  173.     pte = find_mapping_and_check(badvaddr, istate, &pfcr);
  174.     if (!pte) {
  175.         switch (pfcr) {
  176.         case AS_PF_FAULT:
  177.             goto fail;
  178.             break;
  179.         case AS_PF_DEFER:
  180.             /*
  181.              * The page fault came during copy_from_uspace()
  182.              * or copy_to_uspace().
  183.              */
  184.             page_table_unlock(AS, true);
  185.             return;
  186.         default:
  187.             panic("Unexpected pfrc (%d)\n", pfcr);
  188.             break;
  189.         }
  190.     }
  191.  
  192.     /* Record access to PTE */
  193.     pte->a = 1;
  194.    
  195.     page = (badvaddr >> 12) & 0xffff;
  196.     api = (badvaddr >> 22) & 0x3f;
  197.     asm volatile (
  198.         "mfsrin %0, %1\n"
  199.         : "=r" (vsid)
  200.         : "r" (badvaddr)
  201.     );
  202.    
  203.     /* Primary hash (xor) */
  204.     hash = ((vsid ^ page) & 0x3ff) << 3;
  205.    
  206.     /* Find invalid PTE in PTEG */
  207.     for (i = 0; i < 8; i++) {
  208.         if (!phte[hash + i].v)
  209.             break;
  210.     }
  211.    
  212.     // TODO: Check access/change bits, secondary hash
  213.    
  214.     if (i == 8)
  215.         i = page % 8;
  216.    
  217.     phte[hash + i].v = 1;
  218.     phte[hash + i].vsid = vsid;
  219.     phte[hash + i].h = 0;
  220.     phte[hash + i].api = api;
  221.     phte[hash + i].rpn = pte->pfn;
  222.     phte[hash + i].r = 0;
  223.     phte[hash + i].c = 0;
  224.     phte[hash + i].pp = 2; // FIXME
  225.    
  226.     page_table_unlock(AS, true);
  227.     return;
  228.    
  229. fail:
  230.     page_table_unlock(AS, true);
  231.     pht_refill_fail(badvaddr, istate);
  232. }
  233.  
  234.  
  235. /** Print contents of Page Hash Table. */
  236. void tlb_print(void)
  237. {
  238. }
  239.