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(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 void set_pmd_at(struct mm_struct *mm, unsigned long addr, 167 pmd_t *pmdp, pmd_t pmd) 168 { 169 pmd_t orig = *pmdp; 170 171 *pmdp = 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_page(pmd_page(pmd))) 187 mm->context.hugetlb_pte_count++; 188 else 189 mm->context.thp_pte_count++; 190 } else { 191 if (is_huge_zero_page(pmd_page(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 static inline pmd_t pmdp_establish(struct vm_area_struct *vma, 223 unsigned long address, pmd_t *pmdp, pmd_t pmd) 224 { 225 pmd_t old; 226 227 do { 228 old = *pmdp; 229 } while (cmpxchg64(&pmdp->pmd, old.pmd, pmd.pmd) != old.pmd); 230 231 return old; 232 } 233 234 /* 235 * This routine is only called when splitting a THP 236 */ 237 pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address, 238 pmd_t *pmdp) 239 { 240 pmd_t old, entry; 241 242 entry = __pmd(pmd_val(*pmdp) & ~_PAGE_VALID); 243 old = pmdp_establish(vma, address, pmdp, entry); 244 flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE); 245 246 /* 247 * set_pmd_at() will not be called in a way to decrement 248 * thp_pte_count when splitting a THP, so do it now. 249 * Sanity check pmd before doing the actual decrement. 250 */ 251 if ((pmd_val(entry) & _PAGE_PMD_HUGE) && 252 !is_huge_zero_page(pmd_page(entry))) 253 (vma->vm_mm)->context.thp_pte_count--; 254 255 return old; 256 } 257 258 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp, 259 pgtable_t pgtable) 260 { 261 struct list_head *lh = (struct list_head *) pgtable; 262 263 assert_spin_locked(&mm->page_table_lock); 264 265 /* FIFO */ 266 if (!pmd_huge_pte(mm, pmdp)) 267 INIT_LIST_HEAD(lh); 268 else 269 list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp)); 270 pmd_huge_pte(mm, pmdp) = pgtable; 271 } 272 273 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp) 274 { 275 struct list_head *lh; 276 pgtable_t pgtable; 277 278 assert_spin_locked(&mm->page_table_lock); 279 280 /* FIFO */ 281 pgtable = pmd_huge_pte(mm, pmdp); 282 lh = (struct list_head *) pgtable; 283 if (list_empty(lh)) 284 pmd_huge_pte(mm, pmdp) = NULL; 285 else { 286 pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next; 287 list_del(lh); 288 } 289 pte_val(pgtable[0]) = 0; 290 pte_val(pgtable[1]) = 0; 291 292 return pgtable; 293 } 294 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 295