arch/sh/mm/tlb-sh5.c

   1 /*
   2  * arch/sh/mm/tlb-sh5.c
   3  *
   4  * Copyright (C) 2003  Paul Mundt <lethal@linux-sh.org>
   5  * Copyright (C) 2003  Richard Curnow <richard.curnow@superh.com>
   6  *
   7  * This file is subject to the terms and conditions of the GNU General Public
   8  * License.  See the file "COPYING" in the main directory of this archive
   9  * for more details.
  10  */
  11 #include <linux/mm.h>
  12 #include <linux/init.h>
  13 #include <asm/page.h>
  14 #include <asm/tlb.h>
  15 #include <asm/mmu_context.h>
  16
  17 /**
  18  * sh64_tlb_init - Perform initial setup for the DTLB and ITLB.
  19  */
  20 int __init sh64_tlb_init(void)
  21 {
  22         /* Assign some sane DTLB defaults */
  23         cpu_data->dtlb.entries  = 64;
  24         cpu_data->dtlb.step     = 0x10;
  25
  26         cpu_data->dtlb.first    = DTLB_FIXED | cpu_data->dtlb.step;
  27         cpu_data->dtlb.next     = cpu_data->dtlb.first;
  28
  29         cpu_data->dtlb.last     = DTLB_FIXED |
  30                                   ((cpu_data->dtlb.entries - 1) *
  31                                    cpu_data->dtlb.step);
  32
  33         /* And again for the ITLB */
  34         cpu_data->itlb.entries  = 64;
  35         cpu_data->itlb.step     = 0x10;
  36
  37         cpu_data->itlb.first    = ITLB_FIXED | cpu_data->itlb.step;
  38         cpu_data->itlb.next     = cpu_data->itlb.first;
  39         cpu_data->itlb.last     = ITLB_FIXED |
  40                                   ((cpu_data->itlb.entries - 1) *
  41                                    cpu_data->itlb.step);
  42
  43         return 0;
  44 }
  45
  46 /**
  47  * sh64_next_free_dtlb_entry - Find the next available DTLB entry
  48  */
  49 unsigned long long sh64_next_free_dtlb_entry(void)
  50 {
  51         return cpu_data->dtlb.next;
  52 }
  53
  54 /**
  55  * sh64_get_wired_dtlb_entry - Allocate a wired (locked-in) entry in the DTLB
  56  */
  57 unsigned long long sh64_get_wired_dtlb_entry(void)
  58 {
  59         unsigned long long entry = sh64_next_free_dtlb_entry();
  60
  61         cpu_data->dtlb.first += cpu_data->dtlb.step;
  62         cpu_data->dtlb.next  += cpu_data->dtlb.step;
  63
  64         return entry;
  65 }
  66
  67 /**
  68  * sh64_put_wired_dtlb_entry - Free a wired (locked-in) entry in the DTLB.
  69  *
  70  * @entry:      Address of TLB slot.
  71  *
  72  * Works like a stack, last one to allocate must be first one to free.
  73  */
  74 int sh64_put_wired_dtlb_entry(unsigned long long entry)
  75 {
  76         __flush_tlb_slot(entry);
  77
  78         /*
  79          * We don't do any particularly useful tracking of wired entries,
  80          * so this approach works like a stack .. last one to be allocated
  81          * has to be the first one to be freed.
  82          *
  83          * We could potentially load wired entries into a list and work on
  84          * rebalancing the list periodically (which also entails moving the
  85          * contents of a TLB entry) .. though I have a feeling that this is
  86          * more trouble than it's worth.
  87          */
  88
  89         /*
  90          * Entry must be valid .. we don't want any ITLB addresses!
  91          */
  92         if (entry <= DTLB_FIXED)
  93                 return -EINVAL;
  94
  95         /*
  96          * Next, check if we're within range to be freed. (ie, must be the
  97          * entry beneath the first 'free' entry!
  98          */
  99         if (entry < (cpu_data->dtlb.first - cpu_data->dtlb.step))
 100                 return -EINVAL;
 101
 102         /* If we are, then bring this entry back into the list */
 103         cpu_data->dtlb.first    -= cpu_data->dtlb.step;
 104         cpu_data->dtlb.next     = entry;
 105
 106         return 0;
 107 }
 108
 109 /**
 110  * sh64_setup_tlb_slot - Load up a translation in a wired slot.
 111  *
 112  * @config_addr:        Address of TLB slot.
 113  * @eaddr:              Virtual address.
 114  * @asid:               Address Space Identifier.
 115  * @paddr:              Physical address.
 116  *
 117  * Load up a virtual<->physical translation for @eaddr<->@paddr in the
 118  * pre-allocated TLB slot @config_addr (see sh64_get_wired_dtlb_entry).
 119  */
 120 void sh64_setup_tlb_slot(unsigned long long config_addr, unsigned long eaddr,
 121                          unsigned long asid, unsigned long paddr)
 122 {
 123         unsigned long long pteh, ptel;
 124
 125         pteh = neff_sign_extend(eaddr);
 126         pteh &= PAGE_MASK;
 127         pteh |= (asid << PTEH_ASID_SHIFT) | PTEH_VALID;
 128         ptel = neff_sign_extend(paddr);
 129         ptel &= PAGE_MASK;
 130         ptel |= (_PAGE_CACHABLE | _PAGE_READ | _PAGE_WRITE);
 131
 132         asm volatile("putcfg %0, 1, %1\n\t"
 133                         "putcfg %0, 0, %2\n"
 134                         : : "r" (config_addr), "r" (ptel), "r" (pteh));
 135 }
 136
 137 /**
 138  * sh64_teardown_tlb_slot - Teardown a translation.
 139  *
 140  * @config_addr:        Address of TLB slot.
 141  *
 142  * Teardown any existing mapping in the TLB slot @config_addr.
 143  */
 144 void sh64_teardown_tlb_slot(unsigned long long config_addr)
 145         __attribute__ ((alias("__flush_tlb_slot")));
 146
 147 static int dtlb_entry;
 148 static unsigned long long dtlb_entries[64];
 149
 150 void tlb_wire_entry(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
 151 {
 152         unsigned long long entry;
 153         unsigned long paddr, flags;
 154
 155         BUG_ON(dtlb_entry == ARRAY_SIZE(dtlb_entries));
 156
 157         local_irq_save(flags);
 158
 159         entry = sh64_get_wired_dtlb_entry();
 160         dtlb_entries[dtlb_entry++] = entry;
 161
 162         paddr = pte_val(pte) & _PAGE_FLAGS_HARDWARE_MASK;
 163         paddr &= ~PAGE_MASK;
 164
 165         sh64_setup_tlb_slot(entry, addr, get_asid(), paddr);
 166
 167         local_irq_restore(flags);
 168 }
 169
 170 void tlb_unwire_entry(void)
 171 {
 172         unsigned long long entry;
 173         unsigned long flags;
 174
 175         BUG_ON(!dtlb_entry);
 176
 177         local_irq_save(flags);
 178         entry = dtlb_entries[dtlb_entry--];
 179
 180         sh64_teardown_tlb_slot(entry);
 181         sh64_put_wired_dtlb_entry(entry);
 182
 183         local_irq_restore(flags);
 184 }