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  1. /*
  2.  * Copyright (c) 2003-2004 Jakub Jermar
  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. /** @addtogroup mips32mm   
  30.  * @{
  31.  */
  32. /** @file
  33.  */
  34.  
  35. #include <arch/mm/tlb.h>
  36. #include <mm/asid.h>
  37. #include <mm/tlb.h>
  38. #include <mm/page.h>
  39. #include <mm/as.h>
  40. #include <arch/cp0.h>
  41. #include <panic.h>
  42. #include <arch.h>
  43. #include <symtab.h>
  44. #include <synch/spinlock.h>
  45. #include <print.h>
  46. #include <debug.h>
  47. #include <align.h>
  48. #include <interrupt.h>
  49.  
  50. static void tlb_refill_fail(istate_t *);
  51. static void tlb_invalid_fail(istate_t *);
  52. static void tlb_modified_fail(istate_t *);
  53.  
  54. static pte_t *find_mapping_and_check(uintptr_t, int, istate_t *, int *);
  55.  
  56. /** Initialize TLB.
  57.  *
  58.  * Invalidate all entries and mark wired entries.
  59.  */
  60. void tlb_arch_init(void)
  61. {
  62.     int i;
  63.  
  64.     cp0_pagemask_write(TLB_PAGE_MASK_16K);
  65.     cp0_entry_hi_write(0);
  66.     cp0_entry_lo0_write(0);
  67.     cp0_entry_lo1_write(0);
  68.  
  69.     /* Clear and initialize TLB. */
  70.    
  71.     for (i = 0; i < TLB_ENTRY_COUNT; i++) {
  72.         cp0_index_write(i);
  73.         tlbwi();
  74.     }
  75.        
  76.     /*
  77.      * The kernel is going to make use of some wired
  78.      * entries (e.g. mapping kernel stacks in kseg3).
  79.      */
  80.     cp0_wired_write(TLB_WIRED);
  81. }
  82.  
  83. /** Process TLB Refill Exception.
  84.  *
  85.  * @param istate    Interrupted register context.
  86.  */
  87. void tlb_refill(istate_t *istate)
  88. {
  89.     entry_lo_t lo;
  90.     entry_hi_t hi;
  91.     asid_t asid;
  92.     uintptr_t badvaddr;
  93.     pte_t *pte;
  94.     int pfrc;
  95.  
  96.     badvaddr = cp0_badvaddr_read();
  97.  
  98.     spinlock_lock(&AS->lock);
  99.     asid = AS->asid;
  100.     spinlock_unlock(&AS->lock);
  101.  
  102.     page_table_lock(AS, true);
  103.  
  104.     pte = find_mapping_and_check(badvaddr, PF_ACCESS_READ, istate, &pfrc);
  105.     if (!pte) {
  106.         switch (pfrc) {
  107.         case AS_PF_FAULT:
  108.             goto fail;
  109.             break;
  110.         case AS_PF_DEFER:
  111.             /*
  112.              * The page fault came during copy_from_uspace()
  113.              * or copy_to_uspace().
  114.              */
  115.             page_table_unlock(AS, true);
  116.             return;
  117.         default:
  118.             panic("unexpected pfrc (%d)\n", pfrc);
  119.         }
  120.     }
  121.  
  122.     /*
  123.      * Record access to PTE.
  124.      */
  125.     pte->a = 1;
  126.  
  127.     tlb_prepare_entry_hi(&hi, asid, badvaddr);
  128.     tlb_prepare_entry_lo(&lo, pte->g, pte->p, pte->d, pte->cacheable,
  129.         pte->pfn);
  130.  
  131.     /*
  132.      * New entry is to be inserted into TLB
  133.      */
  134.     cp0_entry_hi_write(hi.value);
  135.     if ((badvaddr / PAGE_SIZE) % 2 == 0) {
  136.         cp0_entry_lo0_write(lo.value);
  137.         cp0_entry_lo1_write(0);
  138.     }
  139.     else {
  140.         cp0_entry_lo0_write(0);
  141.         cp0_entry_lo1_write(lo.value);
  142.     }
  143.     cp0_pagemask_write(TLB_PAGE_MASK_16K);
  144.     tlbwr();
  145.  
  146.     page_table_unlock(AS, true);
  147.     return;
  148.    
  149. fail:
  150.     page_table_unlock(AS, true);
  151.     tlb_refill_fail(istate);
  152. }
  153.  
  154. /** Process TLB Invalid Exception.
  155.  *
  156.  * @param istate    Interrupted register context.
  157.  */
  158. void tlb_invalid(istate_t *istate)
  159. {
  160.     tlb_index_t index;
  161.     uintptr_t badvaddr;
  162.     entry_lo_t lo;
  163.     entry_hi_t hi;
  164.     pte_t *pte;
  165.     int pfrc;
  166.  
  167.     badvaddr = cp0_badvaddr_read();
  168.  
  169.     /*
  170.      * Locate the faulting entry in TLB.
  171.      */
  172.     hi.value = cp0_entry_hi_read();
  173.     tlb_prepare_entry_hi(&hi, hi.asid, badvaddr);
  174.     cp0_entry_hi_write(hi.value);
  175.     tlbp();
  176.     index.value = cp0_index_read();
  177.  
  178.     page_table_lock(AS, true); 
  179.    
  180.     /*
  181.      * Fail if the entry is not in TLB.
  182.      */
  183.     if (index.p) {
  184.         printf("TLB entry not found.\n");
  185.         goto fail;
  186.     }
  187.  
  188.     pte = find_mapping_and_check(badvaddr, PF_ACCESS_READ, istate, &pfrc);
  189.     if (!pte) {
  190.         switch (pfrc) {
  191.         case AS_PF_FAULT:
  192.             goto fail;
  193.             break;
  194.         case AS_PF_DEFER:
  195.             /*
  196.              * The page fault came during copy_from_uspace()
  197.              * or copy_to_uspace().
  198.              */
  199.             page_table_unlock(AS, true);             
  200.             return;
  201.         default:
  202.             panic("unexpected pfrc (%d)\n", pfrc);
  203.         }
  204.     }
  205.  
  206.     /*
  207.      * Read the faulting TLB entry.
  208.      */
  209.     tlbr();
  210.  
  211.     /*
  212.      * Record access to PTE.
  213.      */
  214.     pte->a = 1;
  215.  
  216.     tlb_prepare_entry_lo(&lo, pte->g, pte->p, pte->d, pte->cacheable,
  217.         pte->pfn);
  218.  
  219.     /*
  220.      * The entry is to be updated in TLB.
  221.      */
  222.     if ((badvaddr / PAGE_SIZE) % 2 == 0)
  223.         cp0_entry_lo0_write(lo.value);
  224.     else
  225.         cp0_entry_lo1_write(lo.value);
  226.     cp0_pagemask_write(TLB_PAGE_MASK_16K);
  227.     tlbwi();
  228.  
  229.     page_table_unlock(AS, true);
  230.     return;
  231.    
  232. fail:
  233.     page_table_unlock(AS, true);
  234.     tlb_invalid_fail(istate);
  235. }
  236.  
  237. /** Process TLB Modified Exception.
  238.  *
  239.  * @param istate    Interrupted register context.
  240.  */
  241. void tlb_modified(istate_t *istate)
  242. {
  243.     tlb_index_t index;
  244.     uintptr_t badvaddr;
  245.     entry_lo_t lo;
  246.     entry_hi_t hi;
  247.     pte_t *pte;
  248.     int pfrc;
  249.  
  250.     badvaddr = cp0_badvaddr_read();
  251.  
  252.     /*
  253.      * Locate the faulting entry in TLB.
  254.      */
  255.     hi.value = cp0_entry_hi_read();
  256.     tlb_prepare_entry_hi(&hi, hi.asid, badvaddr);
  257.     cp0_entry_hi_write(hi.value);
  258.     tlbp();
  259.     index.value = cp0_index_read();
  260.  
  261.     page_table_lock(AS, true); 
  262.    
  263.     /*
  264.      * Fail if the entry is not in TLB.
  265.      */
  266.     if (index.p) {
  267.         printf("TLB entry not found.\n");
  268.         goto fail;
  269.     }
  270.  
  271.     pte = find_mapping_and_check(badvaddr, PF_ACCESS_WRITE, istate, &pfrc);
  272.     if (!pte) {
  273.         switch (pfrc) {
  274.         case AS_PF_FAULT:
  275.             goto fail;
  276.             break;
  277.         case AS_PF_DEFER:
  278.             /*
  279.              * The page fault came during copy_from_uspace()
  280.              * or copy_to_uspace().
  281.              */
  282.             page_table_unlock(AS, true);             
  283.             return;
  284.         default:
  285.             panic("unexpected pfrc (%d)\n", pfrc);
  286.         }
  287.     }
  288.  
  289.     /*
  290.      * Read the faulting TLB entry.
  291.      */
  292.     tlbr();
  293.  
  294.     /*
  295.      * Record access and write to PTE.
  296.      */
  297.     pte->a = 1;
  298.     pte->d = 1;
  299.  
  300.     tlb_prepare_entry_lo(&lo, pte->g, pte->p, pte->w, pte->cacheable,
  301.         pte->pfn);
  302.  
  303.     /*
  304.      * The entry is to be updated in TLB.
  305.      */
  306.     if ((badvaddr / PAGE_SIZE) % 2 == 0)
  307.         cp0_entry_lo0_write(lo.value);
  308.     else
  309.         cp0_entry_lo1_write(lo.value);
  310.     cp0_pagemask_write(TLB_PAGE_MASK_16K);
  311.     tlbwi();
  312.  
  313.     page_table_unlock(AS, true);
  314.     return;
  315.    
  316. fail:
  317.     page_table_unlock(AS, true);
  318.     tlb_modified_fail(istate);
  319. }
  320.  
  321. void tlb_refill_fail(istate_t *istate)
  322. {
  323.     char *symbol = "";
  324.     char *sym2 = "";
  325.  
  326.     char *s = get_symtab_entry(istate->epc);
  327.     if (s)
  328.         symbol = s;
  329.     s = get_symtab_entry(istate->ra);
  330.     if (s)
  331.         sym2 = s;
  332.  
  333.     fault_if_from_uspace(istate, "TLB Refill Exception on %p",
  334.         cp0_badvaddr_read());
  335.     panic("%x: TLB Refill Exception at %x(%s<-%s)\n", cp0_badvaddr_read(),
  336.         istate->epc, symbol, sym2);
  337. }
  338.  
  339.  
  340. void tlb_invalid_fail(istate_t *istate)
  341. {
  342.     char *symbol = "";
  343.  
  344.     char *s = get_symtab_entry(istate->epc);
  345.     if (s)
  346.         symbol = s;
  347.     fault_if_from_uspace(istate, "TLB Invalid Exception on %p",
  348.         cp0_badvaddr_read());
  349.     panic("%x: TLB Invalid Exception at %x(%s)\n", cp0_badvaddr_read(),
  350.         istate->epc, symbol);
  351. }
  352.  
  353. void tlb_modified_fail(istate_t *istate)
  354. {
  355.     char *symbol = "";
  356.  
  357.     char *s = get_symtab_entry(istate->epc);
  358.     if (s)
  359.         symbol = s;
  360.     fault_if_from_uspace(istate, "TLB Modified Exception on %p",
  361.         cp0_badvaddr_read());
  362.     panic("%x: TLB Modified Exception at %x(%s)\n", cp0_badvaddr_read(),
  363.         istate->epc, symbol);
  364. }
  365.  
  366. /** Try to find PTE for faulting address.
  367.  *
  368.  * The AS->lock must be held on entry to this function.
  369.  *
  370.  * @param badvaddr  Faulting virtual address.
  371.  * @param access    Access mode that caused the fault.
  372.  * @param istate    Pointer to interrupted state.
  373.  * @param pfrc      Pointer to variable where as_page_fault() return code
  374.  *          will be stored.
  375.  *
  376.  * @return      PTE on success, NULL otherwise.
  377.  */
  378. pte_t *
  379. find_mapping_and_check(uintptr_t badvaddr, int access, istate_t *istate,
  380.     int *pfrc)
  381. {
  382.     entry_hi_t hi;
  383.     pte_t *pte;
  384.  
  385.     hi.value = cp0_entry_hi_read();
  386.  
  387.     /*
  388.      * Handler cannot succeed if the ASIDs don't match.
  389.      */
  390.     if (hi.asid != AS->asid) {
  391.         printf("EntryHi.asid=%d, AS->asid=%d\n", hi.asid, AS->asid);
  392.         return NULL;
  393.     }
  394.  
  395.     /*
  396.      * Check if the mapping exists in page tables.
  397.      */
  398.     pte = page_mapping_find(AS, badvaddr);
  399.     if (pte && pte->p && (pte->w || access != PF_ACCESS_WRITE)) {
  400.         /*
  401.          * Mapping found in page tables.
  402.          * Immediately succeed.
  403.          */
  404.         return pte;
  405.     } else {
  406.         int rc;
  407.        
  408.         /*
  409.          * Mapping not found in page tables.
  410.          * Resort to higher-level page fault handler.
  411.          */
  412.         page_table_unlock(AS, true);
  413.         switch (rc = as_page_fault(badvaddr, access, istate)) {
  414.         case AS_PF_OK:
  415.             /*
  416.              * The higher-level page fault handler succeeded,
  417.              * The mapping ought to be in place.
  418.              */
  419.             page_table_lock(AS, true);
  420.             pte = page_mapping_find(AS, badvaddr);
  421.             ASSERT(pte && pte->p);
  422.             ASSERT(pte->w || access != PF_ACCESS_WRITE);
  423.             return pte;
  424.             break;
  425.         case AS_PF_DEFER:
  426.             page_table_lock(AS, true);
  427.             *pfrc = AS_PF_DEFER;
  428.             return NULL;
  429.             break;
  430.         case AS_PF_FAULT:
  431.             page_table_lock(AS, true);
  432.             *pfrc = AS_PF_FAULT;
  433.             return NULL;
  434.             break;
  435.         default:
  436.             panic("unexpected rc (%d)\n", rc);
  437.         }
  438.        
  439.     }
  440. }
  441.  
  442. void
  443. tlb_prepare_entry_lo(entry_lo_t *lo, bool g, bool v, bool d, bool cacheable,
  444.     uintptr_t pfn)
  445. {
  446.     lo->value = 0;
  447.     lo->g = g;
  448.     lo->v = v;
  449.     lo->d = d;
  450.     lo->c = cacheable ? PAGE_CACHEABLE_EXC_WRITE : PAGE_UNCACHED;
  451.     lo->pfn = pfn;
  452. }
  453.  
  454. void tlb_prepare_entry_hi(entry_hi_t *hi, asid_t asid, uintptr_t addr)
  455. {
  456.     hi->value = ALIGN_DOWN(addr, PAGE_SIZE * 2);
  457.     hi->asid = asid;
  458. }
  459.  
  460. /** Print contents of TLB. */
  461. void tlb_print(void)
  462. {
  463.     page_mask_t mask;
  464.     entry_lo_t lo0, lo1;
  465.     entry_hi_t hi, hi_save;
  466.     unsigned int i;
  467.  
  468.     hi_save.value = cp0_entry_hi_read();
  469.    
  470.     printf("#  ASID VPN2   MASK G V D C PFN\n");
  471.     printf("-- ---- ------ ---- - - - - ------\n");
  472.    
  473.     for (i = 0; i < TLB_ENTRY_COUNT; i++) {
  474.         cp0_index_write(i);
  475.         tlbr();
  476.        
  477.         mask.value = cp0_pagemask_read();
  478.         hi.value = cp0_entry_hi_read();
  479.         lo0.value = cp0_entry_lo0_read();
  480.         lo1.value = cp0_entry_lo1_read();
  481.        
  482.         printf("%-2u %-4u %#6x %#4x %1u %1u %1u %1u %#6x\n",
  483.             i, hi.asid, hi.vpn2, mask.mask,
  484.             lo0.g, lo0.v, lo0.d, lo0.c, lo0.pfn);
  485.         printf("                    %1u %1u %1u %1u %#6x\n",
  486.             lo1.g, lo1.v, lo1.d, lo1.c, lo1.pfn);
  487.     }
  488.    
  489.     cp0_entry_hi_write(hi_save.value);
  490. }
  491.  
  492. /** Invalidate all not wired TLB entries. */
  493. void tlb_invalidate_all(void)
  494. {
  495.     ipl_t ipl;
  496.     entry_lo_t lo0, lo1;
  497.     entry_hi_t hi_save;
  498.     int i;
  499.  
  500.     hi_save.value = cp0_entry_hi_read();
  501.     ipl = interrupts_disable();
  502.  
  503.     for (i = TLB_WIRED; i < TLB_ENTRY_COUNT; i++) {
  504.         cp0_index_write(i);
  505.         tlbr();
  506.  
  507.         lo0.value = cp0_entry_lo0_read();
  508.         lo1.value = cp0_entry_lo1_read();
  509.  
  510.         lo0.v = 0;
  511.         lo1.v = 0;
  512.  
  513.         cp0_entry_lo0_write(lo0.value);
  514.         cp0_entry_lo1_write(lo1.value);
  515.                
  516.         tlbwi();
  517.     }
  518.    
  519.     interrupts_restore(ipl);
  520.     cp0_entry_hi_write(hi_save.value);
  521. }
  522.  
  523. /** Invalidate all TLB entries belonging to specified address space.
  524.  *
  525.  * @param asid Address space identifier.
  526.  */
  527. void tlb_invalidate_asid(asid_t asid)
  528. {
  529.     ipl_t ipl;
  530.     entry_lo_t lo0, lo1;
  531.     entry_hi_t hi, hi_save;
  532.     int i;
  533.  
  534.     ASSERT(asid != ASID_INVALID);
  535.  
  536.     hi_save.value = cp0_entry_hi_read();
  537.     ipl = interrupts_disable();
  538.    
  539.     for (i = 0; i < TLB_ENTRY_COUNT; i++) {
  540.         cp0_index_write(i);
  541.         tlbr();
  542.        
  543.         hi.value = cp0_entry_hi_read();
  544.        
  545.         if (hi.asid == asid) {
  546.             lo0.value = cp0_entry_lo0_read();
  547.             lo1.value = cp0_entry_lo1_read();
  548.  
  549.             lo0.v = 0;
  550.             lo1.v = 0;
  551.  
  552.             cp0_entry_lo0_write(lo0.value);
  553.             cp0_entry_lo1_write(lo1.value);
  554.  
  555.             tlbwi();
  556.         }
  557.     }
  558.    
  559.     interrupts_restore(ipl);
  560.     cp0_entry_hi_write(hi_save.value);
  561. }
  562.  
  563. /** Invalidate TLB entries for specified page range belonging to specified
  564.  * address space.
  565.  *
  566.  * @param asid      Address space identifier.
  567.  * @param page      First page whose TLB entry is to be invalidated.
  568.  * @param cnt       Number of entries to invalidate.
  569.  */
  570. void tlb_invalidate_pages(asid_t asid, uintptr_t page, count_t cnt)
  571. {
  572.     unsigned int i;
  573.     ipl_t ipl;
  574.     entry_lo_t lo0, lo1;
  575.     entry_hi_t hi, hi_save;
  576.     tlb_index_t index;
  577.  
  578.     ASSERT(asid != ASID_INVALID);
  579.  
  580.     hi_save.value = cp0_entry_hi_read();
  581.     ipl = interrupts_disable();
  582.  
  583.     for (i = 0; i < cnt + 1; i += 2) {
  584.         hi.value = 0;
  585.         tlb_prepare_entry_hi(&hi, asid, page + i * PAGE_SIZE);
  586.         cp0_entry_hi_write(hi.value);
  587.  
  588.         tlbp();
  589.         index.value = cp0_index_read();
  590.  
  591.         if (!index.p) {
  592.             /*
  593.              * Entry was found, index register contains valid
  594.              * index.
  595.              */
  596.             tlbr();
  597.  
  598.             lo0.value = cp0_entry_lo0_read();
  599.             lo1.value = cp0_entry_lo1_read();
  600.  
  601.             lo0.v = 0;
  602.             lo1.v = 0;
  603.  
  604.             cp0_entry_lo0_write(lo0.value);
  605.             cp0_entry_lo1_write(lo1.value);
  606.  
  607.             tlbwi();
  608.         }
  609.     }
  610.    
  611.     interrupts_restore(ipl);
  612.     cp0_entry_hi_write(hi_save.value);
  613. }
  614.  
  615. /** @}
  616.  */
  617.