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 = this_cpu_ptr(&tlb_batch);
  56
  57         tb->active = 1;
  58 }
  59
  60 void arch_leave_lazy_mmu_mode(void)
  61 {
  62         struct tlb_batch *tb = this_cpu_ptr(&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, unsigned int hugepage_shift)
  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, hugepage_shift);
  88                 global_flush_tlb_page(mm, vaddr);
  89                 goto out;
  90         }
  91
  92         if (nr == 0) {
  93                 tb->mm = mm;
  94                 tb->hugepage_shift = hugepage_shift;
  95         }
  96
  97         if (tb->hugepage_shift != hugepage_shift) {
  98                 flush_tlb_pending();
  99                 tb->hugepage_shift = hugepage_shift;
 100                 nr = 0;
 101         }
 102
 103         tb->vaddrs[nr] = vaddr;
 104         tb->tlb_nr = ++nr;
 105         if (nr >= TLB_BATCH_NR)
 106                 flush_tlb_pending();
 107
 108 out:
 109         put_cpu_var(tlb_batch);
 110 }
 111
 112 void tlb_batch_add(struct mm_struct *mm, unsigned long vaddr,
 113                    pte_t *ptep, pte_t orig, int fullmm,
 114                    unsigned int hugepage_shift)
 115 {
 116         if (tlb_type != hypervisor &&
 117             pte_dirty(orig)) {
 118                 unsigned long paddr, pfn = pte_pfn(orig);
 119                 struct address_space *mapping;
 120                 struct page *page;
 121
 122                 if (!pfn_valid(pfn))
 123                         goto no_cache_flush;
 124
 125                 page = pfn_to_page(pfn);
 126                 if (PageReserved(page))
 127                         goto no_cache_flush;
 128
 129                 /* A real file page? */
 130                 mapping = page_mapping(page);
 131                 if (!mapping)
 132                         goto no_cache_flush;
 133
 134                 paddr = (unsigned long) page_address(page);
 135                 if ((paddr ^ vaddr) & (1 << 13))
 136                         flush_dcache_page_all(mm, page);
 137         }
 138
 139 no_cache_flush:
 140         if (!fullmm)
 141                 tlb_batch_add_one(mm, vaddr, pte_exec(orig), hugepage_shift);
 142 }
 143
 144 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 145 static void tlb_batch_pmd_scan(struct mm_struct *mm, unsigned long vaddr,
 146                                pmd_t pmd)
 147 {
 148         unsigned long end;
 149         pte_t *pte;
 150
 151         pte = pte_offset_map(&pmd, vaddr);
 152         end = vaddr + HPAGE_SIZE;
 153         while (vaddr < end) {
 154                 if (pte_val(*pte) & _PAGE_VALID) {
 155                         bool exec = pte_exec(*pte);
 156
 157                         tlb_batch_add_one(mm, vaddr, exec, PAGE_SHIFT);
 158                 }
 159                 pte++;
 160                 vaddr += PAGE_SIZE;
 161         }
 162         pte_unmap(pte);
 163 }
 164
 165 void set_pmd_at(struct mm_struct *mm, unsigned long addr,
 166                 pmd_t *pmdp, pmd_t pmd)
 167 {
 168         pmd_t orig = *pmdp;
 169
 170         *pmdp = pmd;
 171
 172         if (mm == &init_mm)
 173                 return;
 174
 175         if ((pmd_val(pmd) ^ pmd_val(orig)) & _PAGE_PMD_HUGE) {
 176                 /*
 177                  * Note that this routine only sets pmds for THP pages.
 178                  * Hugetlb pages are handled elsewhere.  We need to check
 179                  * for huge zero page.  Huge zero pages are like hugetlb
 180                  * pages in that there is no RSS, but there is the need
 181                  * for TSB entries.  So, huge zero page counts go into
 182                  * hugetlb_pte_count.
 183                  */
 184                 if (pmd_val(pmd) & _PAGE_PMD_HUGE) {
 185                         if (is_huge_zero_page(pmd_page(pmd)))
 186                                 mm->context.hugetlb_pte_count++;
 187                         else
 188                                 mm->context.thp_pte_count++;
 189                 } else {
 190                         if (is_huge_zero_page(pmd_page(orig)))
 191                                 mm->context.hugetlb_pte_count--;
 192                         else
 193                                 mm->context.thp_pte_count--;
 194                 }
 195
 196                 /* Do not try to allocate the TSB hash table if we
 197                  * don't have one already.  We have various locks held
 198                  * and thus we'll end up doing a GFP_KERNEL allocation
 199                  * in an atomic context.
 200                  *
 201                  * Instead, we let the first TLB miss on a hugepage
 202                  * take care of this.
 203                  */
 204         }
 205
 206         if (!pmd_none(orig)) {
 207                 addr &= HPAGE_MASK;
 208                 if (pmd_trans_huge(orig)) {
 209                         pte_t orig_pte = __pte(pmd_val(orig));
 210                         bool exec = pte_exec(orig_pte);
 211
 212                         tlb_batch_add_one(mm, addr, exec, REAL_HPAGE_SHIFT);
 213                         tlb_batch_add_one(mm, addr + REAL_HPAGE_SIZE, exec,
 214                                           REAL_HPAGE_SHIFT);
 215                 } else {
 216                         tlb_batch_pmd_scan(mm, addr, orig);
 217                 }
 218         }
 219 }
 220
 221 /*
 222  * This routine is only called when splitting a THP
 223  */
 224 void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 225                      pmd_t *pmdp)
 226 {
 227         pmd_t entry = *pmdp;
 228
 229         pmd_val(entry) &= ~_PAGE_VALID;
 230
 231         set_pmd_at(vma->vm_mm, address, pmdp, entry);
 232         flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 233
 234         /*
 235          * set_pmd_at() will not be called in a way to decrement
 236          * thp_pte_count when splitting a THP, so do it now.
 237          * Sanity check pmd before doing the actual decrement.
 238          */
 239         if ((pmd_val(entry) & _PAGE_PMD_HUGE) &&
 240             !is_huge_zero_page(pmd_page(entry)))
 241                 (vma->vm_mm)->context.thp_pte_count--;
 242 }
 243
 244 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 245                                 pgtable_t pgtable)
 246 {
 247         struct list_head *lh = (struct list_head *) pgtable;
 248
 249         assert_spin_locked(&mm->page_table_lock);
 250
 251         /* FIFO */
 252         if (!pmd_huge_pte(mm, pmdp))
 253                 INIT_LIST_HEAD(lh);
 254         else
 255                 list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
 256         pmd_huge_pte(mm, pmdp) = pgtable;
 257 }
 258
 259 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 260 {
 261         struct list_head *lh;
 262         pgtable_t pgtable;
 263
 264         assert_spin_locked(&mm->page_table_lock);
 265
 266         /* FIFO */
 267         pgtable = pmd_huge_pte(mm, pmdp);
 268         lh = (struct list_head *) pgtable;
 269         if (list_empty(lh))
 270                 pmd_huge_pte(mm, pmdp) = NULL;
 271         else {
 272                 pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
 273                 list_del(lh);
 274         }
 275         pte_val(pgtable[0]) = 0;
 276         pte_val(pgtable[1]) = 0;
 277
 278         return pgtable;
 279 }
 280 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */