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 <davem@redhat.com>
   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                 struct folio *folio;
 122
 123                 if (!pfn_valid(pfn))
 124                         goto no_cache_flush;
 125
 126                 page = pfn_to_page(pfn);
 127                 if (PageReserved(page))
 128                         goto no_cache_flush;
 129
 130                 /* A real file page? */
 131                 folio = page_folio(page);
 132                 mapping = folio_flush_mapping(folio);
 133                 if (!mapping)
 134                         goto no_cache_flush;
 135
 136                 paddr = (unsigned long) page_address(page);
 137                 if ((paddr ^ vaddr) & (1 << 13))
 138                         flush_dcache_folio_all(mm, folio);
 139         }
 140
 141 no_cache_flush:
 142         if (!fullmm)
 143                 tlb_batch_add_one(mm, vaddr, pte_exec(orig), hugepage_shift);
 144 }
 145
 146 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 147 static void tlb_batch_pmd_scan(struct mm_struct *mm, unsigned long vaddr,
 148                                pmd_t pmd)
 149 {
 150         unsigned long end;
 151         pte_t *pte;
 152
 153         pte = pte_offset_map(&pmd, vaddr);
 154         if (!pte)
 155                 return;
 156         end = vaddr + HPAGE_SIZE;
 157         while (vaddr < end) {
 158                 if (pte_val(*pte) & _PAGE_VALID) {
 159                         bool exec = pte_exec(*pte);
 160
 161                         tlb_batch_add_one(mm, vaddr, exec, PAGE_SHIFT);
 162                 }
 163                 pte++;
 164                 vaddr += PAGE_SIZE;
 165         }
 166         pte_unmap(pte);
 167 }
 168
 169
 170 static void __set_pmd_acct(struct mm_struct *mm, unsigned long addr,
 171                            pmd_t orig, pmd_t pmd)
 172 {
 173         if (mm == &init_mm)
 174                 return;
 175
 176         if ((pmd_val(pmd) ^ pmd_val(orig)) & _PAGE_PMD_HUGE) {
 177                 /*
 178                  * Note that this routine only sets pmds for THP pages.
 179                  * Hugetlb pages are handled elsewhere.  We need to check
 180                  * for huge zero page.  Huge zero pages are like hugetlb
 181                  * pages in that there is no RSS, but there is the need
 182                  * for TSB entries.  So, huge zero page counts go into
 183                  * hugetlb_pte_count.
 184                  */
 185                 if (pmd_val(pmd) & _PAGE_PMD_HUGE) {
 186                         if (is_huge_zero_page(pmd_page(pmd)))
 187                                 mm->context.hugetlb_pte_count++;
 188                         else
 189                                 mm->context.thp_pte_count++;
 190                 } else {
 191                         if (is_huge_zero_page(pmd_page(orig)))
 192                                 mm->context.hugetlb_pte_count--;
 193                         else
 194                                 mm->context.thp_pte_count--;
 195                 }
 196
 197                 /* Do not try to allocate the TSB hash table if we
 198                  * don't have one already.  We have various locks held
 199                  * and thus we'll end up doing a GFP_KERNEL allocation
 200                  * in an atomic context.
 201                  *
 202                  * Instead, we let the first TLB miss on a hugepage
 203                  * take care of this.
 204                  */
 205         }
 206
 207         if (!pmd_none(orig)) {
 208                 addr &= HPAGE_MASK;
 209                 if (pmd_trans_huge(orig)) {
 210                         pte_t orig_pte = __pte(pmd_val(orig));
 211                         bool exec = pte_exec(orig_pte);
 212
 213                         tlb_batch_add_one(mm, addr, exec, REAL_HPAGE_SHIFT);
 214                         tlb_batch_add_one(mm, addr + REAL_HPAGE_SIZE, exec,
 215                                           REAL_HPAGE_SHIFT);
 216                 } else {
 217                         tlb_batch_pmd_scan(mm, addr, orig);
 218                 }
 219         }
 220 }
 221
 222 void set_pmd_at(struct mm_struct *mm, unsigned long addr,
 223                 pmd_t *pmdp, pmd_t pmd)
 224 {
 225         pmd_t orig = *pmdp;
 226
 227         *pmdp = pmd;
 228         __set_pmd_acct(mm, addr, orig, pmd);
 229 }
 230
 231 static inline pmd_t pmdp_establish(struct vm_area_struct *vma,
 232                 unsigned long address, pmd_t *pmdp, pmd_t pmd)
 233 {
 234         pmd_t old;
 235
 236         do {
 237                 old = *pmdp;
 238         } while (cmpxchg64(&pmdp->pmd, old.pmd, pmd.pmd) != old.pmd);
 239         __set_pmd_acct(vma->vm_mm, address, old, pmd);
 240
 241         return old;
 242 }
 243
 244 /*
 245  * This routine is only called when splitting a THP
 246  */
 247 pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 248                      pmd_t *pmdp)
 249 {
 250         pmd_t old, entry;
 251
 252         entry = __pmd(pmd_val(*pmdp) & ~_PAGE_VALID);
 253         old = pmdp_establish(vma, address, pmdp, entry);
 254         flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 255
 256         /*
 257          * set_pmd_at() will not be called in a way to decrement
 258          * thp_pte_count when splitting a THP, so do it now.
 259          * Sanity check pmd before doing the actual decrement.
 260          */
 261         if ((pmd_val(entry) & _PAGE_PMD_HUGE) &&
 262             !is_huge_zero_page(pmd_page(entry)))
 263                 (vma->vm_mm)->context.thp_pte_count--;
 264
 265         return old;
 266 }
 267
 268 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 269                                 pgtable_t pgtable)
 270 {
 271         struct list_head *lh = (struct list_head *) pgtable;
 272
 273         assert_spin_locked(&mm->page_table_lock);
 274
 275         /* FIFO */
 276         if (!pmd_huge_pte(mm, pmdp))
 277                 INIT_LIST_HEAD(lh);
 278         else
 279                 list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
 280         pmd_huge_pte(mm, pmdp) = pgtable;
 281 }
 282
 283 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 284 {
 285         struct list_head *lh;
 286         pgtable_t pgtable;
 287
 288         assert_spin_locked(&mm->page_table_lock);
 289
 290         /* FIFO */
 291         pgtable = pmd_huge_pte(mm, pmdp);
 292         lh = (struct list_head *) pgtable;
 293         if (list_empty(lh))
 294                 pmd_huge_pte(mm, pmdp) = NULL;
 295         else {
 296                 pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
 297                 list_del(lh);
 298         }
 299         pte_val(pgtable[0]) = 0;
 300         pte_val(pgtable[1]) = 0;
 301
 302         return pgtable;
 303 }
 304 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */