LXR linux/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
  21static DEFINE_PER_CPU(struct tlb_batch, tlb_batch);
  22
  23void 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
  49out:
  50        put_cpu_var(tlb_batch);
  51}
  52
  53void arch_enter_lazy_mmu_mode(void)
  54{
  55        struct tlb_batch *tb = this_cpu_ptr(&tlb_batch);
  56
  57        tb->active = 1;
  58}
  59
  60void 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
  69static 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
 108out:
 109        put_cpu_var(tlb_batch);
 110}
 111
 112void 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
 139no_cache_flush:
 140        if (!fullmm)
 141                tlb_batch_add_one(mm, vaddr, pte_exec(orig), hugepage_shift);
 142}
 143
 144#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 145static 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
 166static 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
 218void 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
 227static 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 */
 243pmd_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
 264void 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
 279pgtable_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 */
 301