1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * This file contains the routines for TLB flushing. 4 * On machines where the MMU uses a hash table to store virtual to 5 * physical translations, these routines flush entries from the 6 * hash table also. 7 * -- paulus 8 * 9 * Derived from arch/ppc/mm/init.c: 10 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) 11 * 12 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au) 13 * and Cort Dougan (PReP) (cort@cs.nmt.edu) 14 * Copyright (C) 1996 Paul Mackerras 15 * 16 * Derived from "arch/i386/mm/init.c" 17 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds 18 */ 19 20 #include <linux/kernel.h> 21 #include <linux/mm.h> 22 #include <linux/init.h> 23 #include <linux/highmem.h> 24 #include <linux/pagemap.h> 25 #include <linux/export.h> 26 27 #include <asm/tlbflush.h> 28 #include <asm/tlb.h> 29 30 #include <mm/mmu_decl.h> 31 32 /* 33 * Called when unmapping pages to flush entries from the TLB/hash table. 34 */ 35 void flush_hash_entry(struct mm_struct *mm, pte_t *ptep, unsigned long addr) 36 { 37 unsigned long ptephys; 38 39 if (Hash) { 40 ptephys = __pa(ptep) & PAGE_MASK; 41 flush_hash_pages(mm->context.id, addr, ptephys, 1); 42 } 43 } 44 EXPORT_SYMBOL(flush_hash_entry); 45 46 /* 47 * Called at the end of a mmu_gather operation to make sure the 48 * TLB flush is completely done. 49 */ 50 void tlb_flush(struct mmu_gather *tlb) 51 { 52 if (!Hash) { 53 /* 54 * 603 needs to flush the whole TLB here since 55 * it doesn't use a hash table. 56 */ 57 _tlbia(); 58 } 59 } 60 61 /* 62 * TLB flushing: 63 * 64 * - flush_tlb_mm(mm) flushes the specified mm context TLB's 65 * - flush_tlb_page(vma, vmaddr) flushes one page 66 * - flush_tlb_range(vma, start, end) flushes a range of pages 67 * - flush_tlb_kernel_range(start, end) flushes kernel pages 68 * 69 * since the hardware hash table functions as an extension of the 70 * tlb as far as the linux tables are concerned, flush it too. 71 * -- Cort 72 */ 73 74 static void flush_range(struct mm_struct *mm, unsigned long start, 75 unsigned long end) 76 { 77 pmd_t *pmd; 78 unsigned long pmd_end; 79 int count; 80 unsigned int ctx = mm->context.id; 81 82 start &= PAGE_MASK; 83 if (!Hash) { 84 if (end - start <= PAGE_SIZE) 85 _tlbie(start); 86 else 87 _tlbia(); 88 return; 89 } 90 if (start >= end) 91 return; 92 end = (end - 1) | ~PAGE_MASK; 93 pmd = pmd_ptr(mm, start); 94 for (;;) { 95 pmd_end = ((start + PGDIR_SIZE) & PGDIR_MASK) - 1; 96 if (pmd_end > end) 97 pmd_end = end; 98 if (!pmd_none(*pmd)) { 99 count = ((pmd_end - start) >> PAGE_SHIFT) + 1; 100 flush_hash_pages(ctx, start, pmd_val(*pmd), count); 101 } 102 if (pmd_end == end) 103 break; 104 start = pmd_end + 1; 105 ++pmd; 106 } 107 } 108 109 /* 110 * Flush kernel TLB entries in the given range 111 */ 112 void flush_tlb_kernel_range(unsigned long start, unsigned long end) 113 { 114 flush_range(&init_mm, start, end); 115 } 116 EXPORT_SYMBOL(flush_tlb_kernel_range); 117 118 /* 119 * Flush all the (user) entries for the address space described by mm. 120 */ 121 void flush_tlb_mm(struct mm_struct *mm) 122 { 123 struct vm_area_struct *mp; 124 125 if (!Hash) { 126 _tlbia(); 127 return; 128 } 129 130 /* 131 * It is safe to go down the mm's list of vmas when called 132 * from dup_mmap, holding mmap_sem. It would also be safe from 133 * unmap_region or exit_mmap, but not from vmtruncate on SMP - 134 * but it seems dup_mmap is the only SMP case which gets here. 135 */ 136 for (mp = mm->mmap; mp != NULL; mp = mp->vm_next) 137 flush_range(mp->vm_mm, mp->vm_start, mp->vm_end); 138 } 139 EXPORT_SYMBOL(flush_tlb_mm); 140 141 void flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr) 142 { 143 struct mm_struct *mm; 144 pmd_t *pmd; 145 146 if (!Hash) { 147 _tlbie(vmaddr); 148 return; 149 } 150 mm = (vmaddr < TASK_SIZE)? vma->vm_mm: &init_mm; 151 pmd = pmd_ptr(mm, vmaddr); 152 if (!pmd_none(*pmd)) 153 flush_hash_pages(mm->context.id, vmaddr, pmd_val(*pmd), 1); 154 } 155 EXPORT_SYMBOL(flush_tlb_page); 156 157 /* 158 * For each address in the range, find the pte for the address 159 * and check _PAGE_HASHPTE bit; if it is set, find and destroy 160 * the corresponding HPTE. 161 */ 162 void flush_tlb_range(struct vm_area_struct *vma, unsigned long start, 163 unsigned long end) 164 { 165 flush_range(vma->vm_mm, start, end); 166 } 167 EXPORT_SYMBOL(flush_tlb_range); 168 169 void __init early_init_mmu(void) 170 { 171 } 172