arch/sparc/mm/tlb.c

   1 /* arch/sparc64/mm/tlb.c
   2  *
   3  * Copyright (C) 2004 David S. Miller <davem@redhat.com>
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/init.h>
   8 #include <linux/percpu.h>
   9 #include <linux/mm.h>
  10 #include <linux/swap.h>
  11 #include <linux/preempt.h>
  12
  13 #include <asm/pgtable.h>
  14 #include <asm/pgalloc.h>
  15 #include <asm/tlbflush.h>
  16 #include <asm/cacheflush.h>
  17 #include <asm/mmu_context.h>
  18 #include <asm/tlb.h>
  19
  20 /* Heavily inspired by the ppc64 code.  */
  21
  22 static DEFINE_PER_CPU(struct tlb_batch, tlb_batch);
  23
  24 void flush_tlb_pending(void)
  25 {
  26         struct tlb_batch *tb = &get_cpu_var(tlb_batch);
  27         struct mm_struct *mm = tb->mm;
  28
  29         if (!tb->tlb_nr)
  30                 goto out;
  31
  32         flush_tsb_user(tb);
  33
  34         if (CTX_VALID(mm->context)) {
  35                 if (tb->tlb_nr == 1) {
  36                         global_flush_tlb_page(mm, tb->vaddrs[0]);
  37                 } else {
  38 #ifdef CONFIG_SMP
  39                         smp_flush_tlb_pending(tb->mm, tb->tlb_nr,
  40                                               &tb->vaddrs[0]);
  41 #else
  42                         __flush_tlb_pending(CTX_HWBITS(tb->mm->context),
  43                                             tb->tlb_nr, &tb->vaddrs[0]);
  44 #endif
  45                 }
  46         }
  47
  48         tb->tlb_nr = 0;
  49
  50 out:
  51         put_cpu_var(tlb_batch);
  52 }
  53
  54 void arch_enter_lazy_mmu_mode(void)
  55 {
  56         struct tlb_batch *tb = &__get_cpu_var(tlb_batch);
  57
  58         tb->active = 1;
  59 }
  60
  61 void arch_leave_lazy_mmu_mode(void)
  62 {
  63         struct tlb_batch *tb = &__get_cpu_var(tlb_batch);
  64
  65         if (tb->tlb_nr)
  66                 flush_tlb_pending();
  67         tb->active = 0;
  68 }
  69
  70 static void tlb_batch_add_one(struct mm_struct *mm, unsigned long vaddr,
  71                               bool exec)
  72 {
  73         struct tlb_batch *tb = &get_cpu_var(tlb_batch);
  74         unsigned long nr;
  75
  76         vaddr &= PAGE_MASK;
  77         if (exec)
  78                 vaddr |= 0x1UL;
  79
  80         nr = tb->tlb_nr;
  81
  82         if (unlikely(nr != 0 && mm != tb->mm)) {
  83                 flush_tlb_pending();
  84                 nr = 0;
  85         }
  86
  87         if (!tb->active) {
  88                 flush_tsb_user_page(mm, vaddr);
  89                 global_flush_tlb_page(mm, vaddr);
  90                 goto out;
  91         }
  92
  93         if (nr == 0)
  94                 tb->mm = mm;
  95
  96         tb->vaddrs[nr] = vaddr;
  97         tb->tlb_nr = ++nr;
  98         if (nr >= TLB_BATCH_NR)
  99                 flush_tlb_pending();
 100
 101 out:
 102         put_cpu_var(tlb_batch);
 103 }
 104
 105 void tlb_batch_add(struct mm_struct *mm, unsigned long vaddr,
 106                    pte_t *ptep, pte_t orig, int fullmm)
 107 {
 108         if (tlb_type != hypervisor &&
 109             pte_dirty(orig)) {
 110                 unsigned long paddr, pfn = pte_pfn(orig);
 111                 struct address_space *mapping;
 112                 struct page *page;
 113
 114                 if (!pfn_valid(pfn))
 115                         goto no_cache_flush;
 116
 117                 page = pfn_to_page(pfn);
 118                 if (PageReserved(page))
 119                         goto no_cache_flush;
 120
 121                 /* A real file page? */
 122                 mapping = page_mapping(page);
 123                 if (!mapping)
 124                         goto no_cache_flush;
 125
 126                 paddr = (unsigned long) page_address(page);
 127                 if ((paddr ^ vaddr) & (1 << 13))
 128                         flush_dcache_page_all(mm, page);
 129         }
 130
 131 no_cache_flush:
 132         if (!fullmm)
 133                 tlb_batch_add_one(mm, vaddr, pte_exec(orig));
 134 }
 135
 136 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 137 static void tlb_batch_pmd_scan(struct mm_struct *mm, unsigned long vaddr,
 138                                pmd_t pmd, bool exec)
 139 {
 140         unsigned long end;
 141         pte_t *pte;
 142
 143         pte = pte_offset_map(&pmd, vaddr);
 144         end = vaddr + HPAGE_SIZE;
 145         while (vaddr < end) {
 146                 if (pte_val(*pte) & _PAGE_VALID)
 147                         tlb_batch_add_one(mm, vaddr, exec);
 148                 pte++;
 149                 vaddr += PAGE_SIZE;
 150         }
 151         pte_unmap(pte);
 152 }
 153
 154 void set_pmd_at(struct mm_struct *mm, unsigned long addr,
 155                 pmd_t *pmdp, pmd_t pmd)
 156 {
 157         pmd_t orig = *pmdp;
 158
 159         *pmdp = pmd;
 160
 161         if (mm == &init_mm)
 162                 return;
 163
 164         if ((pmd_val(pmd) ^ pmd_val(orig)) & PMD_ISHUGE) {
 165                 if (pmd_val(pmd) & PMD_ISHUGE)
 166                         mm->context.huge_pte_count++;
 167                 else
 168                         mm->context.huge_pte_count--;
 169
 170                 /* Do not try to allocate the TSB hash table if we
 171                  * don't have one already.  We have various locks held
 172                  * and thus we'll end up doing a GFP_KERNEL allocation
 173                  * in an atomic context.
 174                  *
 175                  * Instead, we let the first TLB miss on a hugepage
 176                  * take care of this.
 177                  */
 178         }
 179
 180         if (!pmd_none(orig)) {
 181                 bool exec = ((pmd_val(orig) & PMD_HUGE_EXEC) != 0);
 182
 183                 addr &= HPAGE_MASK;
 184                 if (pmd_val(orig) & PMD_ISHUGE)
 185                         tlb_batch_add_one(mm, addr, exec);
 186                 else
 187                         tlb_batch_pmd_scan(mm, addr, orig, exec);
 188         }
 189 }
 190
 191 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 192                                 pgtable_t pgtable)
 193 {
 194         struct list_head *lh = (struct list_head *) pgtable;
 195
 196         assert_spin_locked(&mm->page_table_lock);
 197
 198         /* FIFO */
 199         if (!mm->pmd_huge_pte)
 200                 INIT_LIST_HEAD(lh);
 201         else
 202                 list_add(lh, (struct list_head *) mm->pmd_huge_pte);
 203         mm->pmd_huge_pte = pgtable;
 204 }
 205
 206 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 207 {
 208         struct list_head *lh;
 209         pgtable_t pgtable;
 210
 211         assert_spin_locked(&mm->page_table_lock);
 212
 213         /* FIFO */
 214         pgtable = mm->pmd_huge_pte;
 215         lh = (struct list_head *) pgtable;
 216         if (list_empty(lh))
 217                 mm->pmd_huge_pte = NULL;
 218         else {
 219                 mm->pmd_huge_pte = (pgtable_t) lh->next;
 220                 list_del(lh);
 221         }
 222         pte_val(pgtable[0]) = 0;
 223         pte_val(pgtable[1]) = 0;
 224
 225         return pgtable;
 226 }
 227 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */