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_pmd(pmd)) 187 mm->context.hugetlb_pte_count++; 188 else 189 mm->context.thp_pte_count++; 190 } else { 191 if (is_huge_zero_pmd(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 VM_WARN_ON_ONCE(!pmd_present(*pmdp)); 253 entry = __pmd(pmd_val(*pmdp) & ~_PAGE_VALID); 254 old = pmdp_establish(vma, address, pmdp, entry); 255 flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE); 256 257 /* 258 * set_pmd_at() will not be called in a way to decrement 259 * thp_pte_count when splitting a THP, so do it now. 260 * Sanity check pmd before doing the actual decrement. 261 */ 262 if ((pmd_val(entry) & _PAGE_PMD_HUGE) && 263 !is_huge_zero_pmd(entry)) 264 (vma->vm_mm)->context.thp_pte_count--; 265 266 return old; 267 } 268 269 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp, 270 pgtable_t pgtable) 271 { 272 struct list_head *lh = (struct list_head *) pgtable; 273 274 assert_spin_locked(&mm->page_table_lock); 275 276 /* FIFO */ 277 if (!pmd_huge_pte(mm, pmdp)) 278 INIT_LIST_HEAD(lh); 279 else 280 list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp)); 281 pmd_huge_pte(mm, pmdp) = pgtable; 282 } 283 284 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp) 285 { 286 struct list_head *lh; 287 pgtable_t pgtable; 288 289 assert_spin_locked(&mm->page_table_lock); 290 291 /* FIFO */ 292 pgtable = pmd_huge_pte(mm, pmdp); 293 lh = (struct list_head *) pgtable; 294 if (list_empty(lh)) 295 pmd_huge_pte(mm, pmdp) = NULL; 296 else { 297 pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next; 298 list_del(lh); 299 } 300 pte_val(pgtable[0]) = 0; 301 pte_val(pgtable[1]) = 0; 302 303 return pgtable; 304 } 305 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 306