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Linux/arch/sparc/mm/tlb.c

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  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 
 13 #include <asm/pgtable.h>
 14 #include <asm/pgalloc.h>
 15 #include <asm/tlbflush.h>
 16 #include <asm/cacheflush.h>
 17 #include <asm/mmu_context.h>
 18 #include <asm/tlb.h>
 19 
 20 /* Heavily inspired by the ppc64 code.  */
 21 
 22 static DEFINE_PER_CPU(struct tlb_batch, tlb_batch);
 23 
 24 void flush_tlb_pending(void)
 25 {
 26         struct tlb_batch *tb = &get_cpu_var(tlb_batch);
 27         struct mm_struct *mm = tb->mm;
 28 
 29         if (!tb->tlb_nr)
 30                 goto out;
 31 
 32         flush_tsb_user(tb);
 33 
 34         if (CTX_VALID(mm->context)) {
 35                 if (tb->tlb_nr == 1) {
 36                         global_flush_tlb_page(mm, tb->vaddrs[0]);
 37                 } else {
 38 #ifdef CONFIG_SMP
 39                         smp_flush_tlb_pending(tb->mm, tb->tlb_nr,
 40                                               &tb->vaddrs[0]);
 41 #else
 42                         __flush_tlb_pending(CTX_HWBITS(tb->mm->context),
 43                                             tb->tlb_nr, &tb->vaddrs[0]);
 44 #endif
 45                 }
 46         }
 47 
 48         tb->tlb_nr = 0;
 49 
 50 out:
 51         put_cpu_var(tlb_batch);
 52 }
 53 
 54 void arch_enter_lazy_mmu_mode(void)
 55 {
 56         struct tlb_batch *tb = this_cpu_ptr(&tlb_batch);
 57 
 58         tb->active = 1;
 59 }
 60 
 61 void arch_leave_lazy_mmu_mode(void)
 62 {
 63         struct tlb_batch *tb = this_cpu_ptr(&tlb_batch);
 64 
 65         if (tb->tlb_nr)
 66                 flush_tlb_pending();
 67         tb->active = 0;
 68 }
 69 
 70 static void tlb_batch_add_one(struct mm_struct *mm, unsigned long vaddr,
 71                               bool exec, unsigned int hugepage_shift)
 72 {
 73         struct tlb_batch *tb = &get_cpu_var(tlb_batch);
 74         unsigned long nr;
 75 
 76         vaddr &= PAGE_MASK;
 77         if (exec)
 78                 vaddr |= 0x1UL;
 79 
 80         nr = tb->tlb_nr;
 81 
 82         if (unlikely(nr != 0 && mm != tb->mm)) {
 83                 flush_tlb_pending();
 84                 nr = 0;
 85         }
 86 
 87         if (!tb->active) {
 88                 flush_tsb_user_page(mm, vaddr, hugepage_shift);
 89                 global_flush_tlb_page(mm, vaddr);
 90                 goto out;
 91         }
 92 
 93         if (nr == 0) {
 94                 tb->mm = mm;
 95                 tb->hugepage_shift = hugepage_shift;
 96         }
 97 
 98         if (tb->hugepage_shift != hugepage_shift) {
 99                 flush_tlb_pending();
100                 tb->hugepage_shift = hugepage_shift;
101                 nr = 0;
102         }
103 
104         tb->vaddrs[nr] = vaddr;
105         tb->tlb_nr = ++nr;
106         if (nr >= TLB_BATCH_NR)
107                 flush_tlb_pending();
108 
109 out:
110         put_cpu_var(tlb_batch);
111 }
112 
113 void tlb_batch_add(struct mm_struct *mm, unsigned long vaddr,
114                    pte_t *ptep, pte_t orig, int fullmm,
115                    unsigned int hugepage_shift)
116 {
117         if (tlb_type != hypervisor &&
118             pte_dirty(orig)) {
119                 unsigned long paddr, pfn = pte_pfn(orig);
120                 struct address_space *mapping;
121                 struct page *page;
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                 mapping = page_mapping_file(page);
132                 if (!mapping)
133                         goto no_cache_flush;
134 
135                 paddr = (unsigned long) page_address(page);
136                 if ((paddr ^ vaddr) & (1 << 13))
137                         flush_dcache_page_all(mm, page);
138         }
139 
140 no_cache_flush:
141         if (!fullmm)
142                 tlb_batch_add_one(mm, vaddr, pte_exec(orig), hugepage_shift);
143 }
144 
145 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
146 static void tlb_batch_pmd_scan(struct mm_struct *mm, unsigned long vaddr,
147                                pmd_t pmd)
148 {
149         unsigned long end;
150         pte_t *pte;
151 
152         pte = pte_offset_map(&pmd, vaddr);
153         end = vaddr + HPAGE_SIZE;
154         while (vaddr < end) {
155                 if (pte_val(*pte) & _PAGE_VALID) {
156                         bool exec = pte_exec(*pte);
157 
158                         tlb_batch_add_one(mm, vaddr, exec, PAGE_SHIFT);
159                 }
160                 pte++;
161                 vaddr += PAGE_SIZE;
162         }
163         pte_unmap(pte);
164 }
165 
166 
167 static void __set_pmd_acct(struct mm_struct *mm, unsigned long addr,
168                            pmd_t orig, pmd_t pmd)
169 {
170         if (mm == &init_mm)
171                 return;
172 
173         if ((pmd_val(pmd) ^ pmd_val(orig)) & _PAGE_PMD_HUGE) {
174                 /*
175                  * Note that this routine only sets pmds for THP pages.
176                  * Hugetlb pages are handled elsewhere.  We need to check
177                  * for huge zero page.  Huge zero pages are like hugetlb
178                  * pages in that there is no RSS, but there is the need
179                  * for TSB entries.  So, huge zero page counts go into
180                  * hugetlb_pte_count.
181                  */
182                 if (pmd_val(pmd) & _PAGE_PMD_HUGE) {
183                         if (is_huge_zero_page(pmd_page(pmd)))
184                                 mm->context.hugetlb_pte_count++;
185                         else
186                                 mm->context.thp_pte_count++;
187                 } else {
188                         if (is_huge_zero_page(pmd_page(orig)))
189                                 mm->context.hugetlb_pte_count--;
190                         else
191                                 mm->context.thp_pte_count--;
192                 }
193 
194                 /* Do not try to allocate the TSB hash table if we
195                  * don't have one already.  We have various locks held
196                  * and thus we'll end up doing a GFP_KERNEL allocation
197                  * in an atomic context.
198                  *
199                  * Instead, we let the first TLB miss on a hugepage
200                  * take care of this.
201                  */
202         }
203 
204         if (!pmd_none(orig)) {
205                 addr &= HPAGE_MASK;
206                 if (pmd_trans_huge(orig)) {
207                         pte_t orig_pte = __pte(pmd_val(orig));
208                         bool exec = pte_exec(orig_pte);
209 
210                         tlb_batch_add_one(mm, addr, exec, REAL_HPAGE_SHIFT);
211                         tlb_batch_add_one(mm, addr + REAL_HPAGE_SIZE, exec,
212                                           REAL_HPAGE_SHIFT);
213                 } else {
214                         tlb_batch_pmd_scan(mm, addr, orig);
215                 }
216         }
217 }
218 
219 void set_pmd_at(struct mm_struct *mm, unsigned long addr,
220                 pmd_t *pmdp, pmd_t pmd)
221 {
222         pmd_t orig = *pmdp;
223 
224         *pmdp = pmd;
225         __set_pmd_acct(mm, addr, orig, pmd);
226 }
227 
228 static inline pmd_t pmdp_establish(struct vm_area_struct *vma,
229                 unsigned long address, pmd_t *pmdp, pmd_t pmd)
230 {
231         pmd_t old;
232 
233         do {
234                 old = *pmdp;
235         } while (cmpxchg64(&pmdp->pmd, old.pmd, pmd.pmd) != old.pmd);
236         __set_pmd_acct(vma->vm_mm, address, old, pmd);
237 
238         return old;
239 }
240 
241 /*
242  * This routine is only called when splitting a THP
243  */
244 pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
245                      pmd_t *pmdp)
246 {
247         pmd_t old, entry;
248 
249         entry = __pmd(pmd_val(*pmdp) & ~_PAGE_VALID);
250         old = pmdp_establish(vma, address, pmdp, entry);
251         flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
252 
253         /*
254          * set_pmd_at() will not be called in a way to decrement
255          * thp_pte_count when splitting a THP, so do it now.
256          * Sanity check pmd before doing the actual decrement.
257          */
258         if ((pmd_val(entry) & _PAGE_PMD_HUGE) &&
259             !is_huge_zero_page(pmd_page(entry)))
260                 (vma->vm_mm)->context.thp_pte_count--;
261 
262         return old;
263 }
264 
265 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
266                                 pgtable_t pgtable)
267 {
268         struct list_head *lh = (struct list_head *) pgtable;
269 
270         assert_spin_locked(&mm->page_table_lock);
271 
272         /* FIFO */
273         if (!pmd_huge_pte(mm, pmdp))
274                 INIT_LIST_HEAD(lh);
275         else
276                 list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
277         pmd_huge_pte(mm, pmdp) = pgtable;
278 }
279 
280 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
281 {
282         struct list_head *lh;
283         pgtable_t pgtable;
284 
285         assert_spin_locked(&mm->page_table_lock);
286 
287         /* FIFO */
288         pgtable = pmd_huge_pte(mm, pmdp);
289         lh = (struct list_head *) pgtable;
290         if (list_empty(lh))
291                 pmd_huge_pte(mm, pmdp) = NULL;
292         else {
293                 pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
294                 list_del(lh);
295         }
296         pte_val(pgtable[0]) = 0;
297         pte_val(pgtable[1]) = 0;
298 
299         return pgtable;
300 }
301 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
302 

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