1 /* arch/sparc64/mm/tlb.c 2 * 3 * Copyright (C) 2004 David S. Miller <davem@redhat.com> 4 */ 5 6 #include <linux/kernel.h> 7 #include <linux/percpu.h> 8 #include <linux/mm.h> 9 #include <linux/swap.h> 10 #include <linux/preempt.h> 11 12 #include <asm/pgtable.h> 13 #include <asm/pgalloc.h> 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; 121 122 if (!pfn_valid(pfn)) 123 goto no_cache_flush; 124 125 page = pfn_to_page(pfn); 126 if (PageReserved(page)) 127 goto no_cache_flush; 128 129 /* A real file page? */ 130 mapping = page_mapping(page); 131 if (!mapping) 132 goto no_cache_flush; 133 134 paddr = (unsigned long) page_address(page); 135 if ((paddr ^ vaddr) & (1 << 13)) 136 flush_dcache_page_all(mm, page); 137 } 138 139 no_cache_flush: 140 if (!fullmm) 141 tlb_batch_add_one(mm, vaddr, pte_exec(orig), hugepage_shift); 142 } 143 144 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 145 static void tlb_batch_pmd_scan(struct mm_struct *mm, unsigned long vaddr, 146 pmd_t pmd) 147 { 148 unsigned long end; 149 pte_t *pte; 150 151 pte = pte_offset_map(&pmd, vaddr); 152 end = vaddr + HPAGE_SIZE; 153 while (vaddr < end) { 154 if (pte_val(*pte) & _PAGE_VALID) { 155 bool exec = pte_exec(*pte); 156 157 tlb_batch_add_one(mm, vaddr, exec, false); 158 } 159 pte++; 160 vaddr += PAGE_SIZE; 161 } 162 pte_unmap(pte); 163 } 164 165 void set_pmd_at(struct mm_struct *mm, unsigned long addr, 166 pmd_t *pmdp, pmd_t pmd) 167 { 168 pmd_t orig = *pmdp; 169 170 *pmdp = pmd; 171 172 if (mm == &init_mm) 173 return; 174 175 if ((pmd_val(pmd) ^ pmd_val(orig)) & _PAGE_PMD_HUGE) { 176 /* 177 * Note that this routine only sets pmds for THP pages. 178 * Hugetlb pages are handled elsewhere. We need to check 179 * for huge zero page. Huge zero pages are like hugetlb 180 * pages in that there is no RSS, but there is the need 181 * for TSB entries. So, huge zero page counts go into 182 * hugetlb_pte_count. 183 */ 184 if (pmd_val(pmd) & _PAGE_PMD_HUGE) { 185 if (is_huge_zero_page(pmd_page(pmd))) 186 mm->context.hugetlb_pte_count++; 187 else 188 mm->context.thp_pte_count++; 189 } else { 190 if (is_huge_zero_page(pmd_page(orig))) 191 mm->context.hugetlb_pte_count--; 192 else 193 mm->context.thp_pte_count--; 194 } 195 196 /* Do not try to allocate the TSB hash table if we 197 * don't have one already. We have various locks held 198 * and thus we'll end up doing a GFP_KERNEL allocation 199 * in an atomic context. 200 * 201 * Instead, we let the first TLB miss on a hugepage 202 * take care of this. 203 */ 204 } 205 206 if (!pmd_none(orig)) { 207 addr &= HPAGE_MASK; 208 if (pmd_trans_huge(orig)) { 209 pte_t orig_pte = __pte(pmd_val(orig)); 210 bool exec = pte_exec(orig_pte); 211 212 tlb_batch_add_one(mm, addr, exec, true); 213 tlb_batch_add_one(mm, addr + REAL_HPAGE_SIZE, exec, 214 true); 215 } else { 216 tlb_batch_pmd_scan(mm, addr, orig); 217 } 218 } 219 } 220 221 /* 222 * This routine is only called when splitting a THP 223 */ 224 void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address, 225 pmd_t *pmdp) 226 { 227 pmd_t entry = *pmdp; 228 229 pmd_val(entry) &= ~_PAGE_VALID; 230 231 set_pmd_at(vma->vm_mm, address, pmdp, entry); 232 flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE); 233 234 /* 235 * set_pmd_at() will not be called in a way to decrement 236 * thp_pte_count when splitting a THP, so do it now. 237 * Sanity check pmd before doing the actual decrement. 238 */ 239 if ((pmd_val(entry) & _PAGE_PMD_HUGE) && 240 !is_huge_zero_page(pmd_page(entry))) 241 (vma->vm_mm)->context.thp_pte_count--; 242 } 243 244 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp, 245 pgtable_t pgtable) 246 { 247 struct list_head *lh = (struct list_head *) pgtable; 248 249 assert_spin_locked(&mm->page_table_lock); 250 251 /* FIFO */ 252 if (!pmd_huge_pte(mm, pmdp)) 253 INIT_LIST_HEAD(lh); 254 else 255 list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp)); 256 pmd_huge_pte(mm, pmdp) = pgtable; 257 } 258 259 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp) 260 { 261 struct list_head *lh; 262 pgtable_t pgtable; 263 264 assert_spin_locked(&mm->page_table_lock); 265 266 /* FIFO */ 267 pgtable = pmd_huge_pte(mm, pmdp); 268 lh = (struct list_head *) pgtable; 269 if (list_empty(lh)) 270 pmd_huge_pte(mm, pmdp) = NULL; 271 else { 272 pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next; 273 list_del(lh); 274 } 275 pte_val(pgtable[0]) = 0; 276 pte_val(pgtable[1]) = 0; 277 278 return pgtable; 279 } 280 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 281