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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. static void pht_insert(const __address vaddr, const pfn_t pfn)
  118. {
  119.     __u32 page = (vaddr >> 12) & 0xffff;
  120.     __u32 api = (vaddr >> 22) & 0x3f;
  121.     __u32 vsid;
  122.    
  123.     asm volatile (
  124.         "mfsrin %0, %1\n"
  125.         : "=r" (vsid)
  126.         : "r" (vaddr)
  127.     );
  128.    
  129.     /* Primary hash (xor) */
  130.     __u32 hash = ((vsid ^ page) & 0x3ff) << 3;
  131.    
  132.     __u32 i;
  133.     /* Find unused PTE in PTEG */
  134.     for (i = 0; i < 8; i++) {
  135.         if (!phte[hash + i].v)
  136.             break;
  137.     }
  138.    
  139.     // TODO: Check access/change bits, secondary hash
  140.    
  141.     if (i == 8)
  142.         i = page % 8;
  143.    
  144.     phte[hash + i].v = 1;
  145.     phte[hash + i].vsid = vsid;
  146.     phte[hash + i].h = 0;
  147.     phte[hash + i].api = api;
  148.     phte[hash + i].rpn = pfn;
  149.     phte[hash + i].r = 0;
  150.     phte[hash + i].c = 0;
  151.     phte[hash + i].pp = 2; // FIXME
  152. }
  153.  
  154.  
  155. /** Process Instruction/Data Storage Interrupt
  156.  *
  157.  * @param data   True if Data Storage Interrupt.
  158.  * @param istate Interrupted register context.
  159.  *
  160.  */
  161. void pht_refill(bool data, istate_t *istate)
  162. {
  163.     asid_t asid;
  164.     __address badvaddr;
  165.     pte_t *pte;
  166.    
  167.     int pfcr;
  168.    
  169.     if (data) {
  170.         asm volatile (
  171.             "mfdar %0\n"
  172.             : "=r" (badvaddr)
  173.         );
  174.     } else
  175.         badvaddr = istate->pc;
  176.        
  177.     spinlock_lock(&AS->lock);
  178.     asid = AS->asid;
  179.     spinlock_unlock(&AS->lock);
  180.    
  181.     page_table_lock(AS, true);
  182.    
  183.     pte = find_mapping_and_check(badvaddr, istate, &pfcr);
  184.     if (!pte) {
  185.         switch (pfcr) {
  186.         case AS_PF_FAULT:
  187.             goto fail;
  188.             break;
  189.         case AS_PF_DEFER:
  190.             /*
  191.              * The page fault came during copy_from_uspace()
  192.              * or copy_to_uspace().
  193.              */
  194.             page_table_unlock(AS, true);
  195.             return;
  196.         default:
  197.             panic("Unexpected pfrc (%d)\n", pfcr);
  198.             break;
  199.         }
  200.     }
  201.    
  202.     pte->a = 1; /* Record access to PTE */
  203.     pht_insert(badvaddr, pte->pfn);
  204.    
  205.     page_table_unlock(AS, true);
  206.     return;
  207.    
  208. fail:
  209.     page_table_unlock(AS, true);
  210.     pht_refill_fail(badvaddr, istate);
  211. }
  212.  
  213.  
  214. void pht_init(void)
  215. {
  216.     memsetb((__address) phte, 1 << PHT_BITS, 0);
  217.    
  218.     /* Insert global kernel mapping */
  219.    
  220.     __address cur;
  221.     for (cur = 0; cur < last_frame; cur += FRAME_SIZE) {
  222.         pte_t *pte = page_mapping_find(AS_KERNEL, PA2KA(cur));
  223.         if ((pte) && (pte->p) && (pte->g))
  224.             pht_insert(PA2KA(cur), pte->pfn);
  225.     }
  226. }
  227.  
  228.  
  229. void page_arch_init(void)
  230. {
  231.     if (config.cpu_active == 1) {
  232.         page_mapping_operations = &pt_mapping_operations;
  233.        
  234.         /*
  235.          * PA2KA(identity) mapping for all frames until last_frame.
  236.          */
  237.         __address cur;
  238.         int flags;
  239.        
  240.         for (cur = 0; cur < last_frame; cur += FRAME_SIZE) {
  241.             flags = PAGE_CACHEABLE;
  242.             if ((PA2KA(cur) >= config.base) && (PA2KA(cur) < config.base + config.kernel_size))
  243.                 flags |= PAGE_GLOBAL;
  244.             page_mapping_insert(AS_KERNEL, PA2KA(cur), cur, flags);
  245.         }
  246.        
  247.         /* Allocate page hash table */
  248.         phte_t *physical_phte = (phte_t *) PFN2ADDR(frame_alloc(PHT_ORDER, FRAME_KA | FRAME_PANIC));
  249.         phte = (phte_t *) PA2KA((__address) physical_phte);
  250.        
  251.         ASSERT((__address) physical_phte % (1 << PHT_BITS) == 0);
  252.         pht_init();
  253.        
  254.         asm volatile (
  255.             "mtsdr1 %0\n"
  256.             :
  257.             : "r" ((__address) physical_phte)
  258.         );
  259.        
  260.         /* Invalidate block address translation registers,
  261.            thus remove the temporary mapping */
  262. //      invalidate_bat();
  263.     }
  264. }
  265.