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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 <arch/interrupt.h>
  34. #include <mm/frame.h>
  35. #include <mm/page.h>
  36. #include <mm/as.h>
  37. #include <arch.h>
  38. #include <arch/types.h>
  39. #include <arch/exception.h>
  40. #include <align.h>
  41. #include <config.h>
  42. #include <print.h>
  43. #include <symtab.h>
  44.  
  45. static phte_t *phte;
  46.  
  47.  
  48. /** Try to find PTE for faulting address
  49.  *
  50.  * Try to find PTE for faulting address.
  51.  * The as->lock must be held on entry to this function
  52.  * if lock is true.
  53.  *
  54.  * @param as       Address space.
  55.  * @param lock     Lock/unlock the address space.
  56.  * @param badvaddr Faulting virtual address.
  57.  * @param access   Access mode that caused the fault.
  58.  * @param istate   Pointer to interrupted state.
  59.  * @param pfrc     Pointer to variable where as_page_fault() return code will be stored.
  60.  * @return         PTE on success, NULL otherwise.
  61.  *
  62.  */
  63. static pte_t *find_mapping_and_check(as_t *as, bool lock, __address badvaddr, int access,
  64.                      istate_t *istate, int *pfcr)
  65. {
  66.     /*
  67.      * Check if the mapping exists in page tables.
  68.      */
  69.     pte_t *pte = page_mapping_find(as, badvaddr);
  70.     if ((pte) && (pte->p)) {
  71.         /*
  72.          * Mapping found in page tables.
  73.          * Immediately succeed.
  74.          */
  75.         return pte;
  76.     } else {
  77.         int rc;
  78.    
  79.         /*
  80.          * Mapping not found in page tables.
  81.          * Resort to higher-level page fault handler.
  82.          */
  83.         page_table_unlock(as, lock);
  84.         switch (rc = as_page_fault(badvaddr, access, istate)) {
  85.             case AS_PF_OK:
  86.                 /*
  87.                  * The higher-level page fault handler succeeded,
  88.                  * The mapping ought to be in place.
  89.                  */
  90.                 page_table_lock(as, lock);
  91.                 pte = page_mapping_find(as, badvaddr);
  92.                 ASSERT((pte) && (pte->p));
  93.                 return pte;
  94.             case AS_PF_DEFER:
  95.                 page_table_lock(as, lock);
  96.                 *pfcr = rc;
  97.                 return NULL;
  98.             case AS_PF_FAULT:
  99.                 page_table_lock(as, lock);
  100.                 printf("Page fault.\n");
  101.                 *pfcr = rc;
  102.                 return NULL;
  103.             default:
  104.                 panic("unexpected rc (%d)\n", rc);
  105.         }  
  106.     }
  107. }
  108.  
  109.  
  110. static void pht_refill_fail(__address badvaddr, istate_t *istate)
  111. {
  112.     char *symbol = "";
  113.     char *sym2 = "";
  114.  
  115.     char *s = get_symtab_entry(istate->pc);
  116.     if (s)
  117.         symbol = s;
  118.     s = get_symtab_entry(istate->lr);
  119.     if (s)
  120.         sym2 = s;
  121.     panic("%p: PHT Refill Exception at %p (%s<-%s)\n", badvaddr, istate->pc, symbol, sym2);
  122. }
  123.  
  124.  
  125. static void pht_insert(const __address vaddr, const pfn_t pfn)
  126. {
  127.     __u32 page = (vaddr >> 12) & 0xffff;
  128.     __u32 api = (vaddr >> 22) & 0x3f;
  129.     __u32 vsid;
  130.    
  131.     asm volatile (
  132.         "mfsrin %0, %1\n"
  133.         : "=r" (vsid)
  134.         : "r" (vaddr)
  135.     );
  136.    
  137.     /* Primary hash (xor) */
  138.     __u32 h = 0;
  139.     __u32 hash = vsid ^ page;
  140.     __u32 base = (hash & 0x3ff) << 3;
  141.     __u32 i;
  142.     bool found = false;
  143.    
  144.     /* Find unused or colliding
  145.        PTE in PTEG */
  146.     for (i = 0; i < 8; i++) {
  147.         if ((!phte[base + i].v) || ((phte[base + i].vsid == vsid) && (phte[base + i].api == api))) {
  148.             found = true;
  149.             break;
  150.         }
  151.     }
  152.    
  153.     if (!found) {
  154.         /* Secondary hash (not) */
  155.         __u32 base2 = (~hash & 0x3ff) << 3;
  156.        
  157.         /* Find unused or colliding
  158.            PTE in PTEG */
  159.         for (i = 0; i < 8; i++) {
  160.             if ((!phte[base2 + i].v) || ((phte[base2 + i].vsid == vsid) && (phte[base2 + i].api == api))) {
  161.                 found = true;
  162.                 base = base2;
  163.                 h = 1;
  164.                 break;
  165.             }
  166.         }
  167.        
  168.         if (!found) {
  169.             // TODO: A/C precedence groups
  170.             i = page % 8;
  171.         }
  172.     }
  173.    
  174.     phte[base + i].v = 1;
  175.     phte[base + i].vsid = vsid;
  176.     phte[base + i].h = h;
  177.     phte[base + i].api = api;
  178.     phte[base + i].rpn = pfn;
  179.     phte[base + i].r = 0;
  180.     phte[base + i].c = 0;
  181.     phte[base + i].pp = 2; // FIXME
  182. }
  183.  
  184.  
  185. /** Process Instruction/Data Storage Interrupt
  186.  *
  187.  * @param data   True if Data Storage Interrupt.
  188.  * @param istate Interrupted register context.
  189.  *
  190.  */
  191. void pht_refill(int n, istate_t *istate)
  192. {
  193.     __address badvaddr;
  194.     pte_t *pte;
  195.     int pfcr;
  196.     as_t *as;
  197.     bool lock;
  198.    
  199.     if (AS == NULL) {
  200.         as = AS_KERNEL;
  201.         lock = false;
  202.     } else {
  203.         as = AS;
  204.         lock = true;
  205.     }
  206.    
  207.     if (n == VECTOR_DATA_STORAGE) {
  208.         asm volatile (
  209.             "mfdar %0\n"
  210.             : "=r" (badvaddr)
  211.         );
  212.     } else
  213.         badvaddr = istate->pc;
  214.        
  215.     page_table_lock(as, lock);
  216.    
  217.     pte = find_mapping_and_check(as, lock, badvaddr, PF_ACCESS_READ /* FIXME */, istate, &pfcr);
  218.     if (!pte) {
  219.         switch (pfcr) {
  220.             case AS_PF_FAULT:
  221.                 goto fail;
  222.                 break;
  223.             case AS_PF_DEFER:
  224.                 /*
  225.                  * The page fault came during copy_from_uspace()
  226.                  * or copy_to_uspace().
  227.                  */
  228.                 page_table_unlock(as, lock);
  229.                 return;
  230.             default:
  231.                 panic("Unexpected pfrc (%d)\n", pfcr);
  232.         }
  233.     }
  234.    
  235.     pte->a = 1; /* Record access to PTE */
  236.     pht_insert(badvaddr, pte->pfn);
  237.    
  238.     page_table_unlock(as, lock);
  239.     return;
  240.    
  241. fail:
  242.     page_table_unlock(as, lock);
  243.     pht_refill_fail(badvaddr, istate);
  244. }
  245.  
  246.  
  247. void pht_init(void)
  248. {
  249.     memsetb((__address) phte, 1 << PHT_BITS, 0);
  250. }
  251.  
  252.  
  253. void page_arch_init(void)
  254. {
  255.     if (config.cpu_active == 1) {
  256.         page_mapping_operations = &pt_mapping_operations;
  257.        
  258.         __address cur;
  259.         int flags;
  260.        
  261.         /* Frames below 128 MB are mapped using BAT,
  262.            map rest of the physical memory */
  263.         for (cur = 128 << 20; cur < last_frame; cur += FRAME_SIZE) {
  264.             flags = PAGE_CACHEABLE;
  265.             if ((PA2KA(cur) >= config.base) && (PA2KA(cur) < config.base + config.kernel_size))
  266.                 flags |= PAGE_GLOBAL;
  267.             page_mapping_insert(AS_KERNEL, PA2KA(cur), cur, flags);
  268.         }
  269.        
  270.         /* Allocate page hash table */
  271.         phte_t *physical_phte = (phte_t *) PFN2ADDR(frame_alloc(PHT_ORDER, FRAME_KA | FRAME_PANIC));
  272.         phte = (phte_t *) PA2KA((__address) physical_phte);
  273.        
  274.         ASSERT((__address) physical_phte % (1 << PHT_BITS) == 0);
  275.         pht_init();
  276.        
  277.         asm volatile (
  278.             "mtsdr1 %0\n"
  279.             :
  280.             : "r" ((__address) physical_phte)
  281.         );
  282.     }
  283. }
  284.  
  285.  
  286. __address hw_map(__address physaddr, size_t size)
  287. {
  288.     if (last_frame + ALIGN_UP(size, PAGE_SIZE) > KA2PA(KERNEL_ADDRESS_SPACE_END_ARCH))
  289.         panic("Unable to map physical memory %p (%d bytes)", physaddr, size)
  290.    
  291.     __address virtaddr = PA2KA(last_frame);
  292.     pfn_t i;
  293.     for (i = 0; i < ADDR2PFN(ALIGN_UP(size, PAGE_SIZE)); i++)
  294.         page_mapping_insert(AS_KERNEL, virtaddr + PFN2ADDR(i), physaddr + PFN2ADDR(i), PAGE_NOT_CACHEABLE);
  295.    
  296.     last_frame = ALIGN_UP(last_frame + size, FRAME_SIZE);
  297.    
  298.     return virtaddr;
  299. }
  300.