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
  28         if (tb->tlb_nr) {
  29                 flush_tsb_user(tb);
  30
  31                 if (CTX_VALID(tb->mm->context)) {
  32 #ifdef CONFIG_SMP
  33                         smp_flush_tlb_pending(tb->mm, tb->tlb_nr,
  34                                               &tb->vaddrs[0]);
  35 #else
  36                         __flush_tlb_pending(CTX_HWBITS(tb->mm->context),
  37                                             tb->tlb_nr, &tb->vaddrs[0]);
  38 #endif
  39                 }
  40                 tb->tlb_nr = 0;
  41         }
  42
  43         put_cpu_var(tlb_batch);
  44 }
  45
  46 static void tlb_batch_add_one(struct mm_struct *mm, unsigned long vaddr,
  47                               bool exec)
  48 {
  49         struct tlb_batch *tb = &get_cpu_var(tlb_batch);
  50         unsigned long nr;
  51
  52         vaddr &= PAGE_MASK;
  53         if (exec)
  54                 vaddr |= 0x1UL;
  55
  56         nr = tb->tlb_nr;
  57
  58         if (unlikely(nr != 0 && mm != tb->mm)) {
  59                 flush_tlb_pending();
  60                 nr = 0;
  61         }
  62
  63         if (nr == 0)
  64                 tb->mm = mm;
  65
  66         tb->vaddrs[nr] = vaddr;
  67         tb->tlb_nr = ++nr;
  68         if (nr >= TLB_BATCH_NR)
  69                 flush_tlb_pending();
  70
  71         put_cpu_var(tlb_batch);
  72 }
  73
  74 void tlb_batch_add(struct mm_struct *mm, unsigned long vaddr,
  75                    pte_t *ptep, pte_t orig, int fullmm)
  76 {
  77         if (tlb_type != hypervisor &&
  78             pte_dirty(orig)) {
  79                 unsigned long paddr, pfn = pte_pfn(orig);
  80                 struct address_space *mapping;
  81                 struct page *page;
  82
  83                 if (!pfn_valid(pfn))
  84                         goto no_cache_flush;
  85
  86                 page = pfn_to_page(pfn);
  87                 if (PageReserved(page))
  88                         goto no_cache_flush;
  89
  90                 /* A real file page? */
  91                 mapping = page_mapping(page);
  92                 if (!mapping)
  93                         goto no_cache_flush;
  94
  95                 paddr = (unsigned long) page_address(page);
  96                 if ((paddr ^ vaddr) & (1 << 13))
  97                         flush_dcache_page_all(mm, page);
  98         }
  99
 100 no_cache_flush:
 101         if (!fullmm)
 102                 tlb_batch_add_one(mm, vaddr, pte_exec(orig));
 103 }
 104
 105 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 106 static void tlb_batch_pmd_scan(struct mm_struct *mm, unsigned long vaddr,
 107                                pmd_t pmd, bool exec)
 108 {
 109         unsigned long end;
 110         pte_t *pte;
 111
 112         pte = pte_offset_map(&pmd, vaddr);
 113         end = vaddr + HPAGE_SIZE;
 114         while (vaddr < end) {
 115                 if (pte_val(*pte) & _PAGE_VALID)
 116                         tlb_batch_add_one(mm, vaddr, exec);
 117                 pte++;
 118                 vaddr += PAGE_SIZE;
 119         }
 120         pte_unmap(pte);
 121 }
 122
 123 void set_pmd_at(struct mm_struct *mm, unsigned long addr,
 124                 pmd_t *pmdp, pmd_t pmd)
 125 {
 126         pmd_t orig = *pmdp;
 127
 128         *pmdp = pmd;
 129
 130         if (mm == &init_mm)
 131                 return;
 132
 133         if ((pmd_val(pmd) ^ pmd_val(orig)) & PMD_ISHUGE) {
 134                 if (pmd_val(pmd) & PMD_ISHUGE)
 135                         mm->context.huge_pte_count++;
 136                 else
 137                         mm->context.huge_pte_count--;
 138
 139                 /* Do not try to allocate the TSB hash table if we
 140                  * don't have one already.  We have various locks held
 141                  * and thus we'll end up doing a GFP_KERNEL allocation
 142                  * in an atomic context.
 143                  *
 144                  * Instead, we let the first TLB miss on a hugepage
 145                  * take care of this.
 146                  */
 147         }
 148
 149         if (!pmd_none(orig)) {
 150                 bool exec = ((pmd_val(orig) & PMD_HUGE_EXEC) != 0);
 151
 152                 addr &= HPAGE_MASK;
 153                 if (pmd_val(orig) & PMD_ISHUGE)
 154                         tlb_batch_add_one(mm, addr, exec);
 155                 else
 156                         tlb_batch_pmd_scan(mm, addr, orig, exec);
 157         }
 158 }
 159
 160 void pgtable_trans_huge_deposit(struct mm_struct *mm, pgtable_t pgtable)
 161 {
 162         struct list_head *lh = (struct list_head *) pgtable;
 163
 164         assert_spin_locked(&mm->page_table_lock);
 165
 166         /* FIFO */
 167         if (!mm->pmd_huge_pte)
 168                 INIT_LIST_HEAD(lh);
 169         else
 170                 list_add(lh, (struct list_head *) mm->pmd_huge_pte);
 171         mm->pmd_huge_pte = pgtable;
 172 }
 173
 174 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm)
 175 {
 176         struct list_head *lh;
 177         pgtable_t pgtable;
 178
 179         assert_spin_locked(&mm->page_table_lock);
 180
 181         /* FIFO */
 182         pgtable = mm->pmd_huge_pte;
 183         lh = (struct list_head *) pgtable;
 184         if (list_empty(lh))
 185                 mm->pmd_huge_pte = NULL;
 186         else {
 187                 mm->pmd_huge_pte = (pgtable_t) lh->next;
 188                 list_del(lh);
 189         }
 190         pte_val(pgtable[0]) = 0;
 191         pte_val(pgtable[1]) = 0;
 192
 193         return pgtable;
 194 }
 195 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */