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 #include <linux/pagemap.h>
  13
  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_file(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
 166 static void __set_pmd_acct(struct mm_struct *mm, unsigned long addr,
 167                            pmd_t orig, pmd_t pmd)
 168 {
 169         if (mm == &init_mm)
 170                 return;
 171
 172         if ((pmd_val(pmd) ^ pmd_val(orig)) & _PAGE_PMD_HUGE) {
 173                 /*
 174                  * Note that this routine only sets pmds for THP pages.
 175                  * Hugetlb pages are handled elsewhere.  We need to check
 176                  * for huge zero page.  Huge zero pages are like hugetlb
 177                  * pages in that there is no RSS, but there is the need
 178                  * for TSB entries.  So, huge zero page counts go into
 179                  * hugetlb_pte_count.
 180                  */
 181                 if (pmd_val(pmd) & _PAGE_PMD_HUGE) {
 182                         if (is_huge_zero_page(pmd_page(pmd)))
 183                                 mm->context.hugetlb_pte_count++;
 184                         else
 185                                 mm->context.thp_pte_count++;
 186                 } else {
 187                         if (is_huge_zero_page(pmd_page(orig)))
 188                                 mm->context.hugetlb_pte_count--;
 189                         else
 190                                 mm->context.thp_pte_count--;
 191                 }
 192
 193                 /* Do not try to allocate the TSB hash table if we
 194                  * don't have one already.  We have various locks held
 195                  * and thus we'll end up doing a GFP_KERNEL allocation
 196                  * in an atomic context.
 197                  *
 198                  * Instead, we let the first TLB miss on a hugepage
 199                  * take care of this.
 200                  */
 201         }
 202
 203         if (!pmd_none(orig)) {
 204                 addr &= HPAGE_MASK;
 205                 if (pmd_trans_huge(orig)) {
 206                         pte_t orig_pte = __pte(pmd_val(orig));
 207                         bool exec = pte_exec(orig_pte);
 208
 209                         tlb_batch_add_one(mm, addr, exec, REAL_HPAGE_SHIFT);
 210                         tlb_batch_add_one(mm, addr + REAL_HPAGE_SIZE, exec,
 211                                           REAL_HPAGE_SHIFT);
 212                 } else {
 213                         tlb_batch_pmd_scan(mm, addr, orig);
 214                 }
 215         }
 216 }
 217
 218 void set_pmd_at(struct mm_struct *mm, unsigned long addr,
 219                 pmd_t *pmdp, pmd_t pmd)
 220 {
 221         pmd_t orig = *pmdp;
 222
 223         *pmdp = pmd;
 224         __set_pmd_acct(mm, addr, orig, pmd);
 225 }
 226
 227 static inline pmd_t pmdp_establish(struct vm_area_struct *vma,
 228                 unsigned long address, pmd_t *pmdp, pmd_t pmd)
 229 {
 230         pmd_t old;
 231
 232         do {
 233                 old = *pmdp;
 234         } while (cmpxchg64(&pmdp->pmd, old.pmd, pmd.pmd) != old.pmd);
 235         __set_pmd_acct(vma->vm_mm, address, old, pmd);
 236
 237         return old;
 238 }
 239
 240 /*
 241  * This routine is only called when splitting a THP
 242  */
 243 pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 244                      pmd_t *pmdp)
 245 {
 246         pmd_t old, entry;
 247
 248         entry = __pmd(pmd_val(*pmdp) & ~_PAGE_VALID);
 249         old = pmdp_establish(vma, address, pmdp, entry);
 250         flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 251
 252         /*
 253          * set_pmd_at() will not be called in a way to decrement
 254          * thp_pte_count when splitting a THP, so do it now.
 255          * Sanity check pmd before doing the actual decrement.
 256          */
 257         if ((pmd_val(entry) & _PAGE_PMD_HUGE) &&
 258             !is_huge_zero_page(pmd_page(entry)))
 259                 (vma->vm_mm)->context.thp_pte_count--;
 260
 261         return old;
 262 }
 263
 264 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 265                                 pgtable_t pgtable)
 266 {
 267         struct list_head *lh = (struct list_head *) pgtable;
 268
 269         assert_spin_locked(&mm->page_table_lock);
 270
 271         /* FIFO */
 272         if (!pmd_huge_pte(mm, pmdp))
 273                 INIT_LIST_HEAD(lh);
 274         else
 275                 list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
 276         pmd_huge_pte(mm, pmdp) = pgtable;
 277 }
 278
 279 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 280 {
 281         struct list_head *lh;
 282         pgtable_t pgtable;
 283
 284         assert_spin_locked(&mm->page_table_lock);
 285
 286         /* FIFO */
 287         pgtable = pmd_huge_pte(mm, pmdp);
 288         lh = (struct list_head *) pgtable;
 289         if (list_empty(lh))
 290                 pmd_huge_pte(mm, pmdp) = NULL;
 291         else {
 292                 pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
 293                 list_del(lh);
 294         }
 295         pte_val(pgtable[0]) = 0;
 296         pte_val(pgtable[1]) = 0;
 297
 298         return pgtable;
 299 }
 300 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */