1/*
2 *  linux/arch/arm/mm/flush.c
3 *
4 *  Copyright (C) 1995-2002 Russell King
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10#include <linux/module.h>
11#include <linux/mm.h>
12#include <linux/pagemap.h>
13
14#include <asm/cacheflush.h>
15#include <asm/system.h>
16#include <asm/tlbflush.h>
17
18#include "mm.h"
19
20#ifdef CONFIG_CPU_CACHE_VIPT
21
22#define ALIAS_FLUSH_START	0xffff4000
23
24static void flush_pfn_alias(unsigned long pfn, unsigned long vaddr)
25{
26	unsigned long to = ALIAS_FLUSH_START + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
27	const int zero = 0;
28
29	set_pte_ext(TOP_PTE(to), pfn_pte(pfn, PAGE_KERNEL), 0);
30	flush_tlb_kernel_page(to);
31
32	asm(	"mcrr	p15, 0, %1, %0, c14\n"
33	"	mcr	p15, 0, %2, c7, c10, 4\n"
34	"	mcr	p15, 0, %2, c7, c5, 0\n"
35	    :
36	    : "r" (to), "r" (to + PAGE_SIZE - L1_CACHE_BYTES), "r" (zero)
37	    : "cc");
38}
39
40void flush_cache_mm(struct mm_struct *mm)
41{
42	if (cache_is_vivt()) {
43		if (cpu_isset(smp_processor_id(), mm->cpu_vm_mask))
44			__cpuc_flush_user_all();
45		return;
46	}
47
48	if (cache_is_vipt_aliasing()) {
49		asm(	"mcr	p15, 0, %0, c7, c14, 0\n"
50		"	mcr	p15, 0, %0, c7, c5, 0\n"
51		"	mcr	p15, 0, %0, c7, c10, 4"
52		    :
53		    : "r" (0)
54		    : "cc");
55	}
56}
57
58void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned long end)
59{
60	if (cache_is_vivt()) {
61		if (cpu_isset(smp_processor_id(), vma->vm_mm->cpu_vm_mask))
62			__cpuc_flush_user_range(start & PAGE_MASK, PAGE_ALIGN(end),
63						vma->vm_flags);
64		return;
65	}
66
67	if (cache_is_vipt_aliasing()) {
68		asm(	"mcr	p15, 0, %0, c7, c14, 0\n"
69		"	mcr	p15, 0, %0, c7, c5, 0\n"
70		"	mcr	p15, 0, %0, c7, c10, 4"
71		    :
72		    : "r" (0)
73		    : "cc");
74	}
75}
76
77void flush_cache_page(struct vm_area_struct *vma, unsigned long user_addr, unsigned long pfn)
78{
79	if (cache_is_vivt()) {
80		if (cpu_isset(smp_processor_id(), vma->vm_mm->cpu_vm_mask)) {
81			unsigned long addr = user_addr & PAGE_MASK;
82			__cpuc_flush_user_range(addr, addr + PAGE_SIZE, vma->vm_flags);
83		}
84		return;
85	}
86
87	if (cache_is_vipt_aliasing())
88		flush_pfn_alias(pfn, user_addr);
89}
90
91void flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
92			 unsigned long uaddr, void *kaddr,
93			 unsigned long len, int write)
94{
95	if (cache_is_vivt()) {
96		if (cpu_isset(smp_processor_id(), vma->vm_mm->cpu_vm_mask)) {
97			unsigned long addr = (unsigned long)kaddr;
98			__cpuc_coherent_kern_range(addr, addr + len);
99		}
100		return;
101	}
102
103	if (cache_is_vipt_aliasing()) {
104		flush_pfn_alias(page_to_pfn(page), uaddr);
105		return;
106	}
107
108	/* VIPT non-aliasing cache */
109	if (cpu_isset(smp_processor_id(), vma->vm_mm->cpu_vm_mask) &&
110	    vma->vm_flags & VM_EXEC) {
111		unsigned long addr = (unsigned long)kaddr;
112		/* only flushing the kernel mapping on non-aliasing VIPT */
113		__cpuc_coherent_kern_range(addr, addr + len);
114	}
115}
116#else
117#define flush_pfn_alias(pfn,vaddr)	do { } while (0)
118#endif
119
120void __flush_dcache_page(struct address_space *mapping, struct page *page)
121{
122	/*
123	 * Writeback any data associated with the kernel mapping of this
124	 * page.  This ensures that data in the physical page is mutually
125	 * coherent with the kernels mapping.
126	 */
127	__cpuc_flush_dcache_page(page_address(page));
128
129	/*
130	 * If this is a page cache page, and we have an aliasing VIPT cache,
131	 * we only need to do one flush - which would be at the relevant
132	 * userspace colour, which is congruent with page->index.
133	 */
134	if (mapping && cache_is_vipt_aliasing())
135		flush_pfn_alias(page_to_pfn(page),
136				page->index << PAGE_CACHE_SHIFT);
137}
138
139static void __flush_dcache_aliases(struct address_space *mapping, struct page *page)
140{
141	struct mm_struct *mm = current->active_mm;
142	struct vm_area_struct *mpnt;
143	struct prio_tree_iter iter;
144	pgoff_t pgoff;
145
146	/*
147	 * There are possible user space mappings of this page:
148	 * - VIVT cache: we need to also write back and invalidate all user
149	 *   data in the current VM view associated with this page.
150	 * - aliasing VIPT: we only need to find one mapping of this page.
151	 */
152	pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
153
154	flush_dcache_mmap_lock(mapping);
155	vma_prio_tree_foreach(mpnt, &iter, &mapping->i_mmap, pgoff, pgoff) {
156		unsigned long offset;
157
158		/*
159		 * If this VMA is not in our MM, we can ignore it.
160		 */
161		if (mpnt->vm_mm != mm)
162			continue;
163		if (!(mpnt->vm_flags & VM_MAYSHARE))
164			continue;
165		offset = (pgoff - mpnt->vm_pgoff) << PAGE_SHIFT;
166		flush_cache_page(mpnt, mpnt->vm_start + offset, page_to_pfn(page));
167	}
168	flush_dcache_mmap_unlock(mapping);
169}
170
171/*
172 * Ensure cache coherency between kernel mapping and userspace mapping
173 * of this page.
174 *
175 * We have three cases to consider:
176 *  - VIPT non-aliasing cache: fully coherent so nothing required.
177 *  - VIVT: fully aliasing, so we need to handle every alias in our
178 *          current VM view.
179 *  - VIPT aliasing: need to handle one alias in our current VM view.
180 *
181 * If we need to handle aliasing:
182 *  If the page only exists in the page cache and there are no user
183 *  space mappings, we can be lazy and remember that we may have dirty
184 *  kernel cache lines for later.  Otherwise, we assume we have
185 *  aliasing mappings.
186 *
187 * Note that we disable the lazy flush for SMP.
188 */
189void flush_dcache_page(struct page *page)
190{
191	struct address_space *mapping = page_mapping(page);
192
193#ifndef CONFIG_SMP
194	if (mapping && !mapping_mapped(mapping))
195		set_bit(PG_dcache_dirty, &page->flags);
196	else
197#endif
198	{
199		__flush_dcache_page(mapping, page);
200		if (mapping && cache_is_vivt())
201			__flush_dcache_aliases(mapping, page);
202	}
203}
204EXPORT_SYMBOL(flush_dcache_page);
205
206/*
207 * Flush an anonymous page so that users of get_user_pages()
208 * can safely access the data.  The expected sequence is:
209 *
210 *  get_user_pages()
211 *    -> flush_anon_page
212 *  memcpy() to/from page
213 *  if written to page, flush_dcache_page()
214 */
215void __flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
216{
217	unsigned long pfn;
218
219	/* VIPT non-aliasing caches need do nothing */
220	if (cache_is_vipt_nonaliasing())
221		return;
222
223	/*
224	 * Write back and invalidate userspace mapping.
225	 */
226	pfn = page_to_pfn(page);
227	if (cache_is_vivt()) {
228		flush_cache_page(vma, vmaddr, pfn);
229	} else {
230		/*
231		 * For aliasing VIPT, we can flush an alias of the
232		 * userspace address only.
233		 */
234		flush_pfn_alias(pfn, vmaddr);
235	}
236
237	__cpuc_flush_dcache_page(page_address(page));
238}
239