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 <kunit/visibility.h> 15 16 #include <asm/tlbflush.h> 17 #include <asm/cacheflush.h> 18 #include <asm/mmu_context.h> 19 #include <asm/tlb.h> 20 21 /* Heavily inspired by the ppc64 code. */ 22 23 static DEFINE_PER_CPU(struct tlb_batch, tlb_batch); 24 25 void flush_tlb_pending(void) 26 { 27 struct tlb_batch *tb = &get_cpu_var(tlb_batch); 28 struct mm_struct *mm = tb->mm; 29 30 if (!tb->tlb_nr) 31 goto out; 32 33 flush_tsb_user(tb); 34 35 if (CTX_VALID(mm->context)) { 36 if (tb->tlb_nr == 1) { 37 global_flush_tlb_page(mm, tb->vaddrs[0]); 38 } else { 39 #ifdef CONFIG_SMP 40 smp_flush_tlb_pending(tb->mm, tb->tlb_nr, 41 &tb->vaddrs[0]); 42 #else 43 __flush_tlb_pending(CTX_HWBITS(tb->mm->context), 44 tb->tlb_nr, &tb->vaddrs[0]); 45 #endif 46 } 47 } 48 49 tb->tlb_nr = 0; 50 51 out: 52 put_cpu_var(tlb_batch); 53 } 54 55 void arch_enter_lazy_mmu_mode(void) 56 { 57 preempt_disable(); 58 } 59 /* For lazy_mmu_mode KUnit tests */ 60 EXPORT_SYMBOL_IF_KUNIT(arch_enter_lazy_mmu_mode); 61 62 void arch_flush_lazy_mmu_mode(void) 63 { 64 struct tlb_batch *tb = this_cpu_ptr(&tlb_batch); 65 66 if (tb->tlb_nr) 67 flush_tlb_pending(); 68 } 69 EXPORT_SYMBOL_IF_KUNIT(arch_flush_lazy_mmu_mode); 70 71 void arch_leave_lazy_mmu_mode(void) 72 { 73 arch_flush_lazy_mmu_mode(); 74 preempt_enable(); 75 } 76 EXPORT_SYMBOL_IF_KUNIT(arch_leave_lazy_mmu_mode); 77 78 static void tlb_batch_add_one(struct mm_struct *mm, unsigned long vaddr, 79 bool exec, unsigned int hugepage_shift) 80 { 81 struct tlb_batch *tb = &get_cpu_var(tlb_batch); 82 unsigned long nr; 83 84 vaddr &= PAGE_MASK; 85 if (exec) 86 vaddr |= 0x1UL; 87 88 nr = tb->tlb_nr; 89 90 if (unlikely(nr != 0 && mm != tb->mm)) { 91 flush_tlb_pending(); 92 nr = 0; 93 } 94 95 if (!is_lazy_mmu_mode_active()) { 96 flush_tsb_user_page(mm, vaddr, hugepage_shift); 97 global_flush_tlb_page(mm, vaddr); 98 goto out; 99 } 100 101 if (nr == 0) { 102 tb->mm = mm; 103 tb->hugepage_shift = hugepage_shift; 104 } 105 106 if (tb->hugepage_shift != hugepage_shift) { 107 flush_tlb_pending(); 108 tb->hugepage_shift = hugepage_shift; 109 nr = 0; 110 } 111 112 tb->vaddrs[nr] = vaddr; 113 tb->tlb_nr = ++nr; 114 if (nr >= TLB_BATCH_NR) 115 flush_tlb_pending(); 116 117 out: 118 put_cpu_var(tlb_batch); 119 } 120 121 void tlb_batch_add(struct mm_struct *mm, unsigned long vaddr, 122 pte_t *ptep, pte_t orig, int fullmm, 123 unsigned int hugepage_shift) 124 { 125 if (tlb_type != hypervisor && 126 pte_dirty(orig)) { 127 unsigned long paddr, pfn = pte_pfn(orig); 128 struct address_space *mapping; 129 struct page *page; 130 struct folio *folio; 131 132 if (!pfn_valid(pfn)) 133 goto no_cache_flush; 134 135 page = pfn_to_page(pfn); 136 if (PageReserved(page)) 137 goto no_cache_flush; 138 139 /* A real file page? */ 140 folio = page_folio(page); 141 mapping = folio_flush_mapping(folio); 142 if (!mapping) 143 goto no_cache_flush; 144 145 paddr = (unsigned long) page_address(page); 146 if ((paddr ^ vaddr) & (1 << 13)) 147 flush_dcache_folio_all(mm, folio); 148 } 149 150 no_cache_flush: 151 if (!fullmm) 152 tlb_batch_add_one(mm, vaddr, pte_exec(orig), hugepage_shift); 153 } 154 155 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 156 static void tlb_batch_pmd_scan(struct mm_struct *mm, unsigned long vaddr, 157 pmd_t pmd) 158 { 159 unsigned long end; 160 pte_t *pte; 161 162 pte = pte_offset_map(&pmd, vaddr); 163 if (!pte) 164 return; 165 end = vaddr + HPAGE_SIZE; 166 while (vaddr < end) { 167 if (pte_val(*pte) & _PAGE_VALID) { 168 bool exec = pte_exec(*pte); 169 170 tlb_batch_add_one(mm, vaddr, exec, PAGE_SHIFT); 171 } 172 pte++; 173 vaddr += PAGE_SIZE; 174 } 175 pte_unmap(pte); 176 } 177 178 179 static void __set_pmd_acct(struct mm_struct *mm, unsigned long addr, 180 pmd_t orig, pmd_t pmd) 181 { 182 if (mm == &init_mm) 183 return; 184 185 if ((pmd_val(pmd) ^ pmd_val(orig)) & _PAGE_PMD_HUGE) { 186 /* 187 * Note that this routine only sets pmds for THP pages. 188 * Hugetlb pages are handled elsewhere. We need to check 189 * for huge zero page. Huge zero pages are like hugetlb 190 * pages in that there is no RSS, but there is the need 191 * for TSB entries. So, huge zero page counts go into 192 * hugetlb_pte_count. 193 */ 194 if (pmd_val(pmd) & _PAGE_PMD_HUGE) { 195 if (is_huge_zero_pmd(pmd)) 196 mm->context.hugetlb_pte_count++; 197 else 198 mm->context.thp_pte_count++; 199 } else { 200 if (is_huge_zero_pmd(orig)) 201 mm->context.hugetlb_pte_count--; 202 else 203 mm->context.thp_pte_count--; 204 } 205 206 /* Do not try to allocate the TSB hash table if we 207 * don't have one already. We have various locks held 208 * and thus we'll end up doing a GFP_KERNEL allocation 209 * in an atomic context. 210 * 211 * Instead, we let the first TLB miss on a hugepage 212 * take care of this. 213 */ 214 } 215 216 if (!pmd_none(orig)) { 217 addr &= HPAGE_MASK; 218 if (pmd_trans_huge(orig)) { 219 pte_t orig_pte = __pte(pmd_val(orig)); 220 bool exec = pte_exec(orig_pte); 221 222 tlb_batch_add_one(mm, addr, exec, REAL_HPAGE_SHIFT); 223 tlb_batch_add_one(mm, addr + REAL_HPAGE_SIZE, exec, 224 REAL_HPAGE_SHIFT); 225 } else { 226 tlb_batch_pmd_scan(mm, addr, orig); 227 } 228 } 229 } 230 231 void set_pmd_at(struct mm_struct *mm, unsigned long addr, 232 pmd_t *pmdp, pmd_t pmd) 233 { 234 pmd_t orig = *pmdp; 235 236 *pmdp = pmd; 237 __set_pmd_acct(mm, addr, orig, pmd); 238 } 239 240 static inline pmd_t pmdp_establish(struct vm_area_struct *vma, 241 unsigned long address, pmd_t *pmdp, pmd_t pmd) 242 { 243 pmd_t old; 244 245 do { 246 old = *pmdp; 247 } while (cmpxchg64(&pmdp->pmd, old.pmd, pmd.pmd) != old.pmd); 248 __set_pmd_acct(vma->vm_mm, address, old, pmd); 249 250 return old; 251 } 252 253 /* 254 * This routine is only called when splitting a THP 255 */ 256 pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address, 257 pmd_t *pmdp) 258 { 259 pmd_t old, entry; 260 261 VM_WARN_ON_ONCE(!pmd_present(*pmdp)); 262 entry = __pmd(pmd_val(*pmdp) & ~_PAGE_VALID); 263 old = pmdp_establish(vma, address, pmdp, entry); 264 flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE); 265 266 /* 267 * set_pmd_at() will not be called in a way to decrement 268 * thp_pte_count when splitting a THP, so do it now. 269 * Sanity check pmd before doing the actual decrement. 270 */ 271 if ((pmd_val(entry) & _PAGE_PMD_HUGE) && 272 !is_huge_zero_pmd(entry)) 273 (vma->vm_mm)->context.thp_pte_count--; 274 275 return old; 276 } 277 278 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp, 279 pgtable_t pgtable) 280 { 281 struct list_head *lh = (struct list_head *) pgtable; 282 283 assert_spin_locked(&mm->page_table_lock); 284 285 /* FIFO */ 286 if (!pmd_huge_pte(mm, pmdp)) 287 INIT_LIST_HEAD(lh); 288 else 289 list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp)); 290 pmd_huge_pte(mm, pmdp) = pgtable; 291 } 292 293 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp) 294 { 295 struct list_head *lh; 296 pgtable_t pgtable; 297 298 assert_spin_locked(&mm->page_table_lock); 299 300 /* FIFO */ 301 pgtable = pmd_huge_pte(mm, pmdp); 302 lh = (struct list_head *) pgtable; 303 if (list_empty(lh)) 304 pmd_huge_pte(mm, pmdp) = NULL; 305 else { 306 pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next; 307 list_del(lh); 308 } 309 pte_val(pgtable[0]) = 0; 310 pte_val(pgtable[1]) = 0; 311 312 return pgtable; 313 } 314 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 315