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/percpu.h>
   8 #include <linux/mm.h>
   9 #include <linux/swap.h>
  10 #include <linux/preempt.h>
  11
  12 #include <asm/pgtable.h>
  13 #include <asm/pgalloc.h>
  14 #include <asm/tlbflush.h>
  15 #include <asm/cacheflush.h>
  16 #include <asm/mmu_context.h>
  17 #include <asm/tlb.h>
  18
  19 /* Heavily inspired by the ppc64 code.  */
  20
  21 static DEFINE_PER_CPU(struct tlb_batch, tlb_batch);
  22
  23 void flush_tlb_pending(void)
  24 {
  25         struct tlb_batch *tb = &get_cpu_var(tlb_batch);
  26         struct mm_struct *mm = tb->mm;
  27
  28         if (!tb->tlb_nr)
  29                 goto out;
  30
  31         flush_tsb_user(tb);
  32
  33         if (CTX_VALID(mm->context)) {
  34                 if (tb->tlb_nr == 1) {
  35                         global_flush_tlb_page(mm, tb->vaddrs[0]);
  36                 } else {
  37 #ifdef CONFIG_SMP
  38                         smp_flush_tlb_pending(tb->mm, tb->tlb_nr,
  39                                               &tb->vaddrs[0]);
  40 #else
  41                         __flush_tlb_pending(CTX_HWBITS(tb->mm->context),
  42                                             tb->tlb_nr, &tb->vaddrs[0]);
  43 #endif
  44                 }
  45         }
  46
  47         tb->tlb_nr = 0;
  48
  49 out:
  50         put_cpu_var(tlb_batch);
  51 }
  52
  53 void arch_enter_lazy_mmu_mode(void)
  54 {
  55         struct tlb_batch *tb = &__get_cpu_var(tlb_batch);
  56
  57         tb->active = 1;
  58 }
  59
  60 void arch_leave_lazy_mmu_mode(void)
  61 {
  62         struct tlb_batch *tb = &__get_cpu_var(tlb_batch);
  63
  64         if (tb->tlb_nr)
  65                 flush_tlb_pending();
  66         tb->active = 0;
  67 }
  68
  69 static void tlb_batch_add_one(struct mm_struct *mm, unsigned long vaddr,
  70                               bool exec)
  71 {
  72         struct tlb_batch *tb = &get_cpu_var(tlb_batch);
  73         unsigned long nr;
  74
  75         vaddr &= PAGE_MASK;
  76         if (exec)
  77                 vaddr |= 0x1UL;
  78
  79         nr = tb->tlb_nr;
  80
  81         if (unlikely(nr != 0 && mm != tb->mm)) {
  82                 flush_tlb_pending();
  83                 nr = 0;
  84         }
  85
  86         if (!tb->active) {
  87                 flush_tsb_user_page(mm, vaddr);
  88                 global_flush_tlb_page(mm, vaddr);
  89                 goto out;
  90         }
  91
  92         if (nr == 0)
  93                 tb->mm = mm;
  94
  95         tb->vaddrs[nr] = vaddr;
  96         tb->tlb_nr = ++nr;
  97         if (nr >= TLB_BATCH_NR)
  98                 flush_tlb_pending();
  99
 100 out:
 101         put_cpu_var(tlb_batch);
 102 }
 103
 104 void tlb_batch_add(struct mm_struct *mm, unsigned long vaddr,
 105                    pte_t *ptep, pte_t orig, int fullmm)
 106 {
 107         if (tlb_type != hypervisor &&
 108             pte_dirty(orig)) {
 109                 unsigned long paddr, pfn = pte_pfn(orig);
 110                 struct address_space *mapping;
 111                 struct page *page;
 112
 113                 if (!pfn_valid(pfn))
 114                         goto no_cache_flush;
 115
 116                 page = pfn_to_page(pfn);
 117                 if (PageReserved(page))
 118                         goto no_cache_flush;
 119
 120                 /* A real file page? */
 121                 mapping = page_mapping(page);
 122                 if (!mapping)
 123                         goto no_cache_flush;
 124
 125                 paddr = (unsigned long) page_address(page);
 126                 if ((paddr ^ vaddr) & (1 << 13))
 127                         flush_dcache_page_all(mm, page);
 128         }
 129
 130 no_cache_flush:
 131         if (!fullmm)
 132                 tlb_batch_add_one(mm, vaddr, pte_exec(orig));
 133 }
 134
 135 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 136 static void tlb_batch_pmd_scan(struct mm_struct *mm, unsigned long vaddr,
 137                                pmd_t pmd, bool exec)
 138 {
 139         unsigned long end;
 140         pte_t *pte;
 141
 142         pte = pte_offset_map(&pmd, vaddr);
 143         end = vaddr + HPAGE_SIZE;
 144         while (vaddr < end) {
 145                 if (pte_val(*pte) & _PAGE_VALID)
 146                         tlb_batch_add_one(mm, vaddr, exec);
 147                 pte++;
 148                 vaddr += PAGE_SIZE;
 149         }
 150         pte_unmap(pte);
 151 }
 152
 153 void set_pmd_at(struct mm_struct *mm, unsigned long addr,
 154                 pmd_t *pmdp, pmd_t pmd)
 155 {
 156         pmd_t orig = *pmdp;
 157
 158         *pmdp = pmd;
 159
 160         if (mm == &init_mm)
 161                 return;
 162
 163         if ((pmd_val(pmd) ^ pmd_val(orig)) & _PAGE_PMD_HUGE) {
 164                 if (pmd_val(pmd) & _PAGE_PMD_HUGE)
 165                         mm->context.huge_pte_count++;
 166                 else
 167                         mm->context.huge_pte_count--;
 168
 169                 /* Do not try to allocate the TSB hash table if we
 170                  * don't have one already.  We have various locks held
 171                  * and thus we'll end up doing a GFP_KERNEL allocation
 172                  * in an atomic context.
 173                  *
 174                  * Instead, we let the first TLB miss on a hugepage
 175                  * take care of this.
 176                  */
 177         }
 178
 179         if (!pmd_none(orig)) {
 180                 pte_t orig_pte = __pte(pmd_val(orig));
 181                 bool exec = pte_exec(orig_pte);
 182
 183                 addr &= HPAGE_MASK;
 184                 if (pmd_trans_huge(orig)) {
 185                         tlb_batch_add_one(mm, addr, exec);
 186                         tlb_batch_add_one(mm, addr + REAL_HPAGE_SIZE, exec);
 187                 } else {
 188                         tlb_batch_pmd_scan(mm, addr, orig, exec);
 189                 }
 190         }
 191 }
 192
 193 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 194                                 pgtable_t pgtable)
 195 {
 196         struct list_head *lh = (struct list_head *) pgtable;
 197
 198         assert_spin_locked(&mm->page_table_lock);
 199
 200         /* FIFO */
 201         if (!pmd_huge_pte(mm, pmdp))
 202                 INIT_LIST_HEAD(lh);
 203         else
 204                 list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
 205         pmd_huge_pte(mm, pmdp) = pgtable;
 206 }
 207
 208 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 209 {
 210         struct list_head *lh;
 211         pgtable_t pgtable;
 212
 213         assert_spin_locked(&mm->page_table_lock);
 214
 215         /* FIFO */
 216         pgtable = pmd_huge_pte(mm, pmdp);
 217         lh = (struct list_head *) pgtable;
 218         if (list_empty(lh))
 219                 pmd_huge_pte(mm, pmdp) = NULL;
 220         else {
 221                 pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
 222                 list_del(lh);
 223         }
 224         pte_val(pgtable[0]) = 0;
 225         pte_val(pgtable[1]) = 0;
 226
 227         return pgtable;
 228 }
 229 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */