arch/sparc/mm/tlb.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* arch/sparc64/mm/tlb.c
   3  *
   4  * Copyright (C) 2004 David S. Miller <[email protected]>
   5  */
   6
   7 #include <linux/kernel.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/tlbflush.h>
  14 #include <asm/cacheflush.h>
  15 #include <asm/mmu_context.h>
  16 #include <asm/tlb.h>
  17
  18 /* Heavily inspired by the ppc64 code.  */
  19
  20 static DEFINE_PER_CPU(struct tlb_batch, tlb_batch);
  21
  22 void flush_tlb_pending(void)
  23 {
  24         struct tlb_batch *tb = &get_cpu_var(tlb_batch);
  25         struct mm_struct *mm = tb->mm;
  26
  27         if (!tb->tlb_nr)
  28                 goto out;
  29
  30         flush_tsb_user(tb);
  31
  32         if (CTX_VALID(mm->context)) {
  33                 if (tb->tlb_nr == 1) {
  34                         global_flush_tlb_page(mm, tb->vaddrs[0]);
  35                 } else {
  36 #ifdef CONFIG_SMP
  37                         smp_flush_tlb_pending(tb->mm, tb->tlb_nr,
  38                                               &tb->vaddrs[0]);
  39 #else
  40                         __flush_tlb_pending(CTX_HWBITS(tb->mm->context),
  41                                             tb->tlb_nr, &tb->vaddrs[0]);
  42 #endif
  43                 }
  44         }
  45
  46         tb->tlb_nr = 0;
  47
  48 out:
  49         put_cpu_var(tlb_batch);
  50 }
  51
  52 void arch_enter_lazy_mmu_mode(void)
  53 {
  54         struct tlb_batch *tb = this_cpu_ptr(&tlb_batch);
  55
  56         tb->active = 1;
  57 }
  58
  59 void arch_leave_lazy_mmu_mode(void)
  60 {
  61         struct tlb_batch *tb = this_cpu_ptr(&tlb_batch);
  62
  63         if (tb->tlb_nr)
  64                 flush_tlb_pending();
  65         tb->active = 0;
  66 }
  67
  68 static void tlb_batch_add_one(struct mm_struct *mm, unsigned long vaddr,
  69                               bool exec, unsigned int hugepage_shift)
  70 {
  71         struct tlb_batch *tb = &get_cpu_var(tlb_batch);
  72         unsigned long nr;
  73
  74         vaddr &= PAGE_MASK;
  75         if (exec)
  76                 vaddr |= 0x1UL;
  77
  78         nr = tb->tlb_nr;
  79
  80         if (unlikely(nr != 0 && mm != tb->mm)) {
  81                 flush_tlb_pending();
  82                 nr = 0;
  83         }
  84
  85         if (!tb->active) {
  86                 flush_tsb_user_page(mm, vaddr, hugepage_shift);
  87                 global_flush_tlb_page(mm, vaddr);
  88                 goto out;
  89         }
  90
  91         if (nr == 0) {
  92                 tb->mm = mm;
  93                 tb->hugepage_shift = hugepage_shift;
  94         }
  95
  96         if (tb->hugepage_shift != hugepage_shift) {
  97                 flush_tlb_pending();
  98                 tb->hugepage_shift = hugepage_shift;
  99                 nr = 0;
 100         }
 101
 102         tb->vaddrs[nr] = vaddr;
 103         tb->tlb_nr = ++nr;
 104         if (nr >= TLB_BATCH_NR)
 105                 flush_tlb_pending();
 106
 107 out:
 108         put_cpu_var(tlb_batch);
 109 }
 110
 111 void tlb_batch_add(struct mm_struct *mm, unsigned long vaddr,
 112                    pte_t *ptep, pte_t orig, int fullmm,
 113                    unsigned int hugepage_shift)
 114 {
 115         if (tlb_type != hypervisor &&
 116             pte_dirty(orig)) {
 117                 unsigned long paddr, pfn = pte_pfn(orig);
 118                 struct address_space *mapping;
 119                 struct page *page;
 120
 121                 if (!pfn_valid(pfn))
 122                         goto no_cache_flush;
 123
 124                 page = pfn_to_page(pfn);
 125                 if (PageReserved(page))
 126                         goto no_cache_flush;
 127
 128                 /* A real file page? */
 129                 mapping = page_mapping_file(page);
 130                 if (!mapping)
 131                         goto no_cache_flush;
 132
 133                 paddr = (unsigned long) page_address(page);
 134                 if ((paddr ^ vaddr) & (1 << 13))
 135                         flush_dcache_page_all(mm, page);
 136         }
 137
 138 no_cache_flush:
 139         if (!fullmm)
 140                 tlb_batch_add_one(mm, vaddr, pte_exec(orig), hugepage_shift);
 141 }
 142
 143 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 144 static void tlb_batch_pmd_scan(struct mm_struct *mm, unsigned long vaddr,
 145                                pmd_t pmd)
 146 {
 147         unsigned long end;
 148         pte_t *pte;
 149
 150         pte = pte_offset_map(&pmd, vaddr);
 151         end = vaddr + HPAGE_SIZE;
 152         while (vaddr < end) {
 153                 if (pte_val(*pte) & _PAGE_VALID) {
 154                         bool exec = pte_exec(*pte);
 155
 156                         tlb_batch_add_one(mm, vaddr, exec, PAGE_SHIFT);
 157                 }
 158                 pte++;
 159                 vaddr += PAGE_SIZE;
 160         }
 161         pte_unmap(pte);
 162 }
 163
 164
 165 static void __set_pmd_acct(struct mm_struct *mm, unsigned long addr,
 166                            pmd_t orig, pmd_t pmd)
 167 {
 168         if (mm == &init_mm)
 169                 return;
 170
 171         if ((pmd_val(pmd) ^ pmd_val(orig)) & _PAGE_PMD_HUGE) {
 172                 /*
 173                  * Note that this routine only sets pmds for THP pages.
 174                  * Hugetlb pages are handled elsewhere.  We need to check
 175                  * for huge zero page.  Huge zero pages are like hugetlb
 176                  * pages in that there is no RSS, but there is the need
 177                  * for TSB entries.  So, huge zero page counts go into
 178                  * hugetlb_pte_count.
 179                  */
 180                 if (pmd_val(pmd) & _PAGE_PMD_HUGE) {
 181                         if (is_huge_zero_page(pmd_page(pmd)))
 182                                 mm->context.hugetlb_pte_count++;
 183                         else
 184                                 mm->context.thp_pte_count++;
 185                 } else {
 186                         if (is_huge_zero_page(pmd_page(orig)))
 187                                 mm->context.hugetlb_pte_count--;
 188                         else
 189                                 mm->context.thp_pte_count--;
 190                 }
 191
 192                 /* Do not try to allocate the TSB hash table if we
 193                  * don't have one already.  We have various locks held
 194                  * and thus we'll end up doing a GFP_KERNEL allocation
 195                  * in an atomic context.
 196                  *
 197                  * Instead, we let the first TLB miss on a hugepage
 198                  * take care of this.
 199                  */
 200         }
 201
 202         if (!pmd_none(orig)) {
 203                 addr &= HPAGE_MASK;
 204                 if (pmd_trans_huge(orig)) {
 205                         pte_t orig_pte = __pte(pmd_val(orig));
 206                         bool exec = pte_exec(orig_pte);
 207
 208                         tlb_batch_add_one(mm, addr, exec, REAL_HPAGE_SHIFT);
 209                         tlb_batch_add_one(mm, addr + REAL_HPAGE_SIZE, exec,
 210                                           REAL_HPAGE_SHIFT);
 211                 } else {
 212                         tlb_batch_pmd_scan(mm, addr, orig);
 213                 }
 214         }
 215 }
 216
 217 void set_pmd_at(struct mm_struct *mm, unsigned long addr,
 218                 pmd_t *pmdp, pmd_t pmd)
 219 {
 220         pmd_t orig = *pmdp;
 221
 222         *pmdp = pmd;
 223         __set_pmd_acct(mm, addr, orig, pmd);
 224 }
 225
 226 static inline pmd_t pmdp_establish(struct vm_area_struct *vma,
 227                 unsigned long address, pmd_t *pmdp, pmd_t pmd)
 228 {
 229         pmd_t old;
 230
 231         do {
 232                 old = *pmdp;
 233         } while (cmpxchg64(&pmdp->pmd, old.pmd, pmd.pmd) != old.pmd);
 234         __set_pmd_acct(vma->vm_mm, address, old, pmd);
 235
 236         return old;
 237 }
 238
 239 /*
 240  * This routine is only called when splitting a THP
 241  */
 242 pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 243                      pmd_t *pmdp)
 244 {
 245         pmd_t old, entry;
 246
 247         entry = __pmd(pmd_val(*pmdp) & ~_PAGE_VALID);
 248         old = pmdp_establish(vma, address, pmdp, entry);
 249         flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 250
 251         /*
 252          * set_pmd_at() will not be called in a way to decrement
 253          * thp_pte_count when splitting a THP, so do it now.
 254          * Sanity check pmd before doing the actual decrement.
 255          */
 256         if ((pmd_val(entry) & _PAGE_PMD_HUGE) &&
 257             !is_huge_zero_page(pmd_page(entry)))
 258                 (vma->vm_mm)->context.thp_pte_count--;
 259
 260         return old;
 261 }
 262
 263 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 264                                 pgtable_t pgtable)
 265 {
 266         struct list_head *lh = (struct list_head *) pgtable;
 267
 268         assert_spin_locked(&mm->page_table_lock);
 269
 270         /* FIFO */
 271         if (!pmd_huge_pte(mm, pmdp))
 272                 INIT_LIST_HEAD(lh);
 273         else
 274                 list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
 275         pmd_huge_pte(mm, pmdp) = pgtable;
 276 }
 277
 278 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 279 {
 280         struct list_head *lh;
 281         pgtable_t pgtable;
 282
 283         assert_spin_locked(&mm->page_table_lock);
 284
 285         /* FIFO */
 286         pgtable = pmd_huge_pte(mm, pmdp);
 287         lh = (struct list_head *) pgtable;
 288         if (list_empty(lh))
 289                 pmd_huge_pte(mm, pmdp) = NULL;
 290         else {
 291                 pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
 292                 list_del(lh);
 293         }
 294         pte_val(pgtable[0]) = 0;
 295         pte_val(pgtable[1]) = 0;
 296
 297         return pgtable;
 298 }
 299 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */