xref: /openbmc/linux/arch/powerpc/mm/book3s32/tlb.c (revision b159eecc)
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_off(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_lock.  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_off(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