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  1. /*
  2.  * Copyright (C) 2005 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/page.h>
  30. #include <genarch/mm/page_pt.h>
  31. #include <arch/mm/frame.h>
  32. #include <arch/asm.h>
  33. #include <mm/frame.h>
  34. #include <mm/page.h>
  35. #include <mm/as.h>
  36. #include <arch.h>
  37. #include <arch/types.h>
  38. #include <arch/exception.h>
  39. #include <config.h>
  40. #include <print.h>
  41. #include <symtab.h>
  42.  
  43. static phte_t *phte;
  44.  
  45.  
  46. /** Try to find PTE for faulting address
  47.  *
  48.  * Try to find PTE for faulting address.
  49.  * The AS->lock must be held on entry to this function.
  50.  *
  51.  * @param badvaddr Faulting virtual address.
  52.  * @param istate   Pointer to interrupted state.
  53.  * @param pfrc     Pointer to variable where as_page_fault() return code will be stored.
  54.  * @return         PTE on success, NULL otherwise.
  55.  *
  56.  */
  57. static pte_t *find_mapping_and_check(__address badvaddr, istate_t *istate, int *pfcr)
  58. {
  59.     /*
  60.      * Check if the mapping exists in page tables.
  61.      */
  62.     pte_t *pte = page_mapping_find(AS, badvaddr);
  63.     if ((pte) && (pte->p)) {
  64.         /*
  65.          * Mapping found in page tables.
  66.          * Immediately succeed.
  67.          */
  68.         return pte;
  69.     } else {
  70.         int rc;
  71.    
  72.         /*
  73.          * Mapping not found in page tables.
  74.          * Resort to higher-level page fault handler.
  75.          */
  76.         page_table_unlock(AS, true);
  77.         switch (rc = as_page_fault(badvaddr, istate)) {
  78.             case AS_PF_OK:
  79.                 /*
  80.                  * The higher-level page fault handler succeeded,
  81.                  * The mapping ought to be in place.
  82.                  */
  83.                 page_table_lock(AS, true);
  84.                 pte = page_mapping_find(AS, badvaddr);
  85.                 ASSERT((pte) && (pte->p));
  86.                 return pte;
  87.             case AS_PF_DEFER:
  88.                 page_table_lock(AS, true);
  89.                 *pfcr = rc;
  90.                 return NULL;
  91.             case AS_PF_FAULT:
  92.                 page_table_lock(AS, true);
  93.                 printf("Page fault.\n");
  94.                 *pfcr = rc;
  95.                 return NULL;
  96.             default:
  97.                 panic("unexpected rc (%d)\n", rc);
  98.         }  
  99.     }
  100. }
  101.  
  102.  
  103. static void pht_refill_fail(__address badvaddr, istate_t *istate)
  104. {
  105.     char *symbol = "";
  106.     char *sym2 = "";
  107.  
  108.     char *s = get_symtab_entry(istate->pc);
  109.     if (s)
  110.         symbol = s;
  111.     s = get_symtab_entry(istate->lr);
  112.     if (s)
  113.         sym2 = s;
  114.     panic("%p: PHT Refill Exception at %p (%s<-%s)\n", badvaddr, istate->pc, symbol, sym2);
  115. }
  116.  
  117.  
  118. static void pht_insert(const __address vaddr, const pfn_t pfn)
  119. {
  120.     __u32 page = (vaddr >> 12) & 0xffff;
  121.     __u32 api = (vaddr >> 22) & 0x3f;
  122.     __u32 vsid;
  123.    
  124.     asm volatile (
  125.         "mfsrin %0, %1\n"
  126.         : "=r" (vsid)
  127.         : "r" (vaddr)
  128.     );
  129.    
  130.     /* Primary hash (xor) */
  131.     __u32 hash = ((vsid ^ page) & 0x3ff) << 3;
  132.    
  133.     __u32 i;
  134.     bool found = false;
  135.     /* Find unused PTE in PTEG */
  136.     for (i = 0; i < 8; i++) {
  137.         if (!phte[hash + i].v) {
  138.             found = true;
  139.             break;
  140.         }
  141.     }
  142.    
  143.     if (!found) {
  144.         /* Secondary hash (not) */
  145.         hash = ~hash;
  146.        
  147.         /* Find unused PTE in PTEG */
  148.         for (i = 0; i < 8; i++) {
  149.             if (!phte[hash + i].v) {
  150.                 found = true;
  151.                 break;
  152.             }
  153.         }
  154.        
  155.         if (!found) {
  156.             // TODO: A/C precedence groups
  157.             i = page % 8;
  158.         }
  159.     }
  160.    
  161.     phte[hash + i].v = 1;
  162.     phte[hash + i].vsid = vsid;
  163.     phte[hash + i].h = 0;
  164.     phte[hash + i].api = api;
  165.     phte[hash + i].rpn = pfn;
  166.     phte[hash + i].r = 0;
  167.     phte[hash + i].c = 0;
  168.     phte[hash + i].pp = 2; // FIXME
  169. }
  170.  
  171.  
  172. /** Process Instruction/Data Storage Interrupt
  173.  *
  174.  * @param data   True if Data Storage Interrupt.
  175.  * @param istate Interrupted register context.
  176.  *
  177.  */
  178. void pht_refill(bool data, istate_t *istate)
  179. {
  180.     asid_t asid;
  181.     __address badvaddr;
  182.     pte_t *pte;
  183.    
  184.     int pfcr;
  185.    
  186.     if (data) {
  187.         asm volatile (
  188.             "mfdar %0\n"
  189.             : "=r" (badvaddr)
  190.         );
  191.     } else
  192.         badvaddr = istate->pc;
  193.        
  194.     spinlock_lock(&AS->lock);
  195.     asid = AS->asid;
  196.     spinlock_unlock(&AS->lock);
  197.    
  198.     page_table_lock(AS, true);
  199.    
  200.     pte = find_mapping_and_check(badvaddr, istate, &pfcr);
  201.     if (!pte) {
  202.         switch (pfcr) {
  203.             case AS_PF_FAULT:
  204.                 goto fail;
  205.                 break;
  206.             case AS_PF_DEFER:
  207.                 /*
  208.                  * The page fault came during copy_from_uspace()
  209.                  * or copy_to_uspace().
  210.                  */
  211.                 page_table_unlock(AS, true);
  212.                 return;
  213.             default:
  214.                 panic("Unexpected pfrc (%d)\n", pfcr);
  215.         }
  216.     }
  217.    
  218.     pte->a = 1; /* Record access to PTE */
  219.     pht_insert(badvaddr, pte->pfn);
  220.    
  221.     page_table_unlock(AS, true);
  222.     return;
  223.    
  224. fail:
  225.     page_table_unlock(AS, true);
  226.     pht_refill_fail(badvaddr, istate);
  227. }
  228.  
  229.  
  230. void pht_init(void)
  231. {
  232.     memsetb((__address) phte, 1 << PHT_BITS, 0);
  233. }
  234.  
  235.  
  236. void page_arch_init(void)
  237. {
  238.     if (config.cpu_active == 1) {
  239.         page_mapping_operations = &pt_mapping_operations;
  240.        
  241.         /*
  242.          * PA2KA(identity) mapping for all frames until last_frame.
  243.          */
  244.         __address cur;
  245.         int flags;
  246.        
  247.         for (cur = 0; cur < last_frame; cur += FRAME_SIZE) {
  248.             flags = PAGE_CACHEABLE;
  249.             if ((PA2KA(cur) >= config.base) && (PA2KA(cur) < config.base + config.kernel_size))
  250.                 flags |= PAGE_GLOBAL;
  251.             page_mapping_insert(AS_KERNEL, PA2KA(cur), cur, flags);
  252.         }
  253.        
  254.         /* Allocate page hash table */
  255.         phte_t *physical_phte = (phte_t *) PFN2ADDR(frame_alloc(PHT_ORDER, FRAME_KA | FRAME_PANIC));
  256.         phte = (phte_t *) PA2KA((__address) physical_phte);
  257.        
  258.         ASSERT((__address) physical_phte % (1 << PHT_BITS) == 0);
  259.         pht_init();
  260.        
  261.         asm volatile (
  262.             "mtsdr1 %0\n"
  263.             :
  264.             : "r" ((__address) physical_phte)
  265.         );
  266.     }
  267. }
  268.