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/tlbflush.h> 14 #include <asm/cacheflush.h> 15 #include <asm/mmu_context.h> 16 #include <asm/tlb.h> 17 18 /* Heavily inspired by the ppc64 code. */ 19 20 static DEFINE_PER_CPU(struct tlb_batch, tlb_batch); 21 22 void flush_tlb_pending(void) 23 { 24 struct tlb_batch *tb = &get_cpu_var(tlb_batch); 25 struct mm_struct *mm = tb->mm; 26 27 if (!tb->tlb_nr) 28 goto out; 29 30 flush_tsb_user(tb); 31 32 if (CTX_VALID(mm->context)) { 33 if (tb->tlb_nr == 1) { 34 global_flush_tlb_page(mm, tb->vaddrs[0]); 35 } else { 36 #ifdef CONFIG_SMP 37 smp_flush_tlb_pending(tb->mm, tb->tlb_nr, 38 &tb->vaddrs[0]); 39 #else 40 __flush_tlb_pending(CTX_HWBITS(tb->mm->context), 41 tb->tlb_nr, &tb->vaddrs[0]); 42 #endif 43 } 44 } 45 46 tb->tlb_nr = 0; 47 48 out: 49 put_cpu_var(tlb_batch); 50 } 51 52 void arch_enter_lazy_mmu_mode(void) 53 { 54 struct tlb_batch *tb = this_cpu_ptr(&tlb_batch); 55 56 tb->active = 1; 57 } 58 59 void arch_leave_lazy_mmu_mode(void) 60 { 61 struct tlb_batch *tb = this_cpu_ptr(&tlb_batch); 62 63 if (tb->tlb_nr) 64 flush_tlb_pending(); 65 tb->active = 0; 66 } 67 68 static void tlb_batch_add_one(struct mm_struct *mm, unsigned long vaddr, 69 bool exec, unsigned int hugepage_shift) 70 { 71 struct tlb_batch *tb = &get_cpu_var(tlb_batch); 72 unsigned long nr; 73 74 vaddr &= PAGE_MASK; 75 if (exec) 76 vaddr |= 0x1UL; 77 78 nr = tb->tlb_nr; 79 80 if (unlikely(nr != 0 && mm != tb->mm)) { 81 flush_tlb_pending(); 82 nr = 0; 83 } 84 85 if (!tb->active) { 86 flush_tsb_user_page(mm, vaddr, hugepage_shift); 87 global_flush_tlb_page(mm, vaddr); 88 goto out; 89 } 90 91 if (nr == 0) { 92 tb->mm = mm; 93 tb->hugepage_shift = hugepage_shift; 94 } 95 96 if (tb->hugepage_shift != hugepage_shift) { 97 flush_tlb_pending(); 98 tb->hugepage_shift = hugepage_shift; 99 nr = 0; 100 } 101 102 tb->vaddrs[nr] = vaddr; 103 tb->tlb_nr = ++nr; 104 if (nr >= TLB_BATCH_NR) 105 flush_tlb_pending(); 106 107 out: 108 put_cpu_var(tlb_batch); 109 } 110 111 void tlb_batch_add(struct mm_struct *mm, unsigned long vaddr, 112 pte_t *ptep, pte_t orig, int fullmm, 113 unsigned int hugepage_shift) 114 { 115 if (tlb_type != hypervisor && 116 pte_dirty(orig)) { 117 unsigned long paddr, pfn = pte_pfn(orig); 118 struct address_space *mapping; 119 struct page *page; 120 121 if (!pfn_valid(pfn)) 122 goto no_cache_flush; 123 124 page = pfn_to_page(pfn); 125 if (PageReserved(page)) 126 goto no_cache_flush; 127 128 /* A real file page? */ 129 mapping = page_mapping_file(page); 130 if (!mapping) 131 goto no_cache_flush; 132 133 paddr = (unsigned long) page_address(page); 134 if ((paddr ^ vaddr) & (1 << 13)) 135 flush_dcache_page_all(mm, page); 136 } 137 138 no_cache_flush: 139 if (!fullmm) 140 tlb_batch_add_one(mm, vaddr, pte_exec(orig), hugepage_shift); 141 } 142 143 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 144 static void tlb_batch_pmd_scan(struct mm_struct *mm, unsigned long vaddr, 145 pmd_t pmd) 146 { 147 unsigned long end; 148 pte_t *pte; 149 150 pte = pte_offset_map(&pmd, vaddr); 151 end = vaddr + HPAGE_SIZE; 152 while (vaddr < end) { 153 if (pte_val(*pte) & _PAGE_VALID) { 154 bool exec = pte_exec(*pte); 155 156 tlb_batch_add_one(mm, vaddr, exec, PAGE_SHIFT); 157 } 158 pte++; 159 vaddr += PAGE_SIZE; 160 } 161 pte_unmap(pte); 162 } 163 164 165 static void __set_pmd_acct(struct mm_struct *mm, unsigned long addr, 166 pmd_t orig, pmd_t pmd) 167 { 168 if (mm == &init_mm) 169 return; 170 171 if ((pmd_val(pmd) ^ pmd_val(orig)) & _PAGE_PMD_HUGE) { 172 /* 173 * Note that this routine only sets pmds for THP pages. 174 * Hugetlb pages are handled elsewhere. We need to check 175 * for huge zero page. Huge zero pages are like hugetlb 176 * pages in that there is no RSS, but there is the need 177 * for TSB entries. So, huge zero page counts go into 178 * hugetlb_pte_count. 179 */ 180 if (pmd_val(pmd) & _PAGE_PMD_HUGE) { 181 if (is_huge_zero_page(pmd_page(pmd))) 182 mm->context.hugetlb_pte_count++; 183 else 184 mm->context.thp_pte_count++; 185 } else { 186 if (is_huge_zero_page(pmd_page(orig))) 187 mm->context.hugetlb_pte_count--; 188 else 189 mm->context.thp_pte_count--; 190 } 191 192 /* Do not try to allocate the TSB hash table if we 193 * don't have one already. We have various locks held 194 * and thus we'll end up doing a GFP_KERNEL allocation 195 * in an atomic context. 196 * 197 * Instead, we let the first TLB miss on a hugepage 198 * take care of this. 199 */ 200 } 201 202 if (!pmd_none(orig)) { 203 addr &= HPAGE_MASK; 204 if (pmd_trans_huge(orig)) { 205 pte_t orig_pte = __pte(pmd_val(orig)); 206 bool exec = pte_exec(orig_pte); 207 208 tlb_batch_add_one(mm, addr, exec, REAL_HPAGE_SHIFT); 209 tlb_batch_add_one(mm, addr + REAL_HPAGE_SIZE, exec, 210 REAL_HPAGE_SHIFT); 211 } else { 212 tlb_batch_pmd_scan(mm, addr, orig); 213 } 214 } 215 } 216 217 void set_pmd_at(struct mm_struct *mm, unsigned long addr, 218 pmd_t *pmdp, pmd_t pmd) 219 { 220 pmd_t orig = *pmdp; 221 222 *pmdp = pmd; 223 __set_pmd_acct(mm, addr, orig, pmd); 224 } 225 226 static inline pmd_t pmdp_establish(struct vm_area_struct *vma, 227 unsigned long address, pmd_t *pmdp, pmd_t pmd) 228 { 229 pmd_t old; 230 231 do { 232 old = *pmdp; 233 } while (cmpxchg64(&pmdp->pmd, old.pmd, pmd.pmd) != old.pmd); 234 __set_pmd_acct(vma->vm_mm, address, old, pmd); 235 236 return old; 237 } 238 239 /* 240 * This routine is only called when splitting a THP 241 */ 242 pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address, 243 pmd_t *pmdp) 244 { 245 pmd_t old, entry; 246 247 entry = __pmd(pmd_val(*pmdp) & ~_PAGE_VALID); 248 old = pmdp_establish(vma, address, pmdp, entry); 249 flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE); 250 251 /* 252 * set_pmd_at() will not be called in a way to decrement 253 * thp_pte_count when splitting a THP, so do it now. 254 * Sanity check pmd before doing the actual decrement. 255 */ 256 if ((pmd_val(entry) & _PAGE_PMD_HUGE) && 257 !is_huge_zero_page(pmd_page(entry))) 258 (vma->vm_mm)->context.thp_pte_count--; 259 260 return old; 261 } 262 263 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp, 264 pgtable_t pgtable) 265 { 266 struct list_head *lh = (struct list_head *) pgtable; 267 268 assert_spin_locked(&mm->page_table_lock); 269 270 /* FIFO */ 271 if (!pmd_huge_pte(mm, pmdp)) 272 INIT_LIST_HEAD(lh); 273 else 274 list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp)); 275 pmd_huge_pte(mm, pmdp) = pgtable; 276 } 277 278 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp) 279 { 280 struct list_head *lh; 281 pgtable_t pgtable; 282 283 assert_spin_locked(&mm->page_table_lock); 284 285 /* FIFO */ 286 pgtable = pmd_huge_pte(mm, pmdp); 287 lh = (struct list_head *) pgtable; 288 if (list_empty(lh)) 289 pmd_huge_pte(mm, pmdp) = NULL; 290 else { 291 pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next; 292 list_del(lh); 293 } 294 pte_val(pgtable[0]) = 0; 295 pte_val(pgtable[1]) = 0; 296 297 return pgtable; 298 } 299 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 300