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#include <linux/highmem.h>
14
15#include <asm/cacheflush.h>
16#include <asm/cachetype.h>
17#include <asm/highmem.h>
18#include <asm/smp_plat.h>
19#include <asm/tlbflush.h>
20
21#include "mm.h"
22
23#ifdef CONFIG_CPU_CACHE_VIPT
24
25static void flush_pfn_alias(unsigned long pfn, unsigned long vaddr)
26{
27	unsigned long to = FLUSH_ALIAS_START + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
28	const int zero = 0;
29
30	set_top_pte(to, pfn_pte(pfn, PAGE_KERNEL));
31
32	asm(	"mcrr	p15, 0, %1, %0, c14\n"
33	"	mcr	p15, 0, %2, c7, c10, 4"
34	    :
35	    : "r" (to), "r" (to + PAGE_SIZE - L1_CACHE_BYTES), "r" (zero)
36	    : "cc");
37}
38
39static void flush_icache_alias(unsigned long pfn, unsigned long vaddr, unsigned long len)
40{
41	unsigned long va = FLUSH_ALIAS_START + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
42	unsigned long offset = vaddr & (PAGE_SIZE - 1);
43	unsigned long to;
44
45	set_top_pte(va, pfn_pte(pfn, PAGE_KERNEL));
46	to = va + offset;
47	flush_icache_range(to, to + len);
48}
49
50void flush_cache_mm(struct mm_struct *mm)
51{
52	if (cache_is_vivt()) {
53		vivt_flush_cache_mm(mm);
54		return;
55	}
56
57	if (cache_is_vipt_aliasing()) {
58		asm(	"mcr	p15, 0, %0, c7, c14, 0\n"
59		"	mcr	p15, 0, %0, c7, c10, 4"
60		    :
61		    : "r" (0)
62		    : "cc");
63	}
64}
65
66void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned long end)
67{
68	if (cache_is_vivt()) {
69		vivt_flush_cache_range(vma, start, end);
70		return;
71	}
72
73	if (cache_is_vipt_aliasing()) {
74		asm(	"mcr	p15, 0, %0, c7, c14, 0\n"
75		"	mcr	p15, 0, %0, c7, c10, 4"
76		    :
77		    : "r" (0)
78		    : "cc");
79	}
80
81	if (vma->vm_flags & VM_EXEC)
82		__flush_icache_all();
83}
84
85void flush_cache_page(struct vm_area_struct *vma, unsigned long user_addr, unsigned long pfn)
86{
87	if (cache_is_vivt()) {
88		vivt_flush_cache_page(vma, user_addr, pfn);
89		return;
90	}
91
92	if (cache_is_vipt_aliasing()) {
93		flush_pfn_alias(pfn, user_addr);
94		__flush_icache_all();
95	}
96
97	if (vma->vm_flags & VM_EXEC && icache_is_vivt_asid_tagged())
98		__flush_icache_all();
99}
100
101#else
102#define flush_pfn_alias(pfn,vaddr)		do { } while (0)
103#define flush_icache_alias(pfn,vaddr,len)	do { } while (0)
104#endif
105
106static void flush_ptrace_access_other(void *args)
107{
108	__flush_icache_all();
109}
110
111static
112void flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
113			 unsigned long uaddr, void *kaddr, unsigned long len)
114{
115	if (cache_is_vivt()) {
116		if (cpumask_test_cpu(smp_processor_id(), mm_cpumask(vma->vm_mm))) {
117			unsigned long addr = (unsigned long)kaddr;
118			__cpuc_coherent_kern_range(addr, addr + len);
119		}
120		return;
121	}
122
123	if (cache_is_vipt_aliasing()) {
124		flush_pfn_alias(page_to_pfn(page), uaddr);
125		__flush_icache_all();
126		return;
127	}
128
129	/* VIPT non-aliasing D-cache */
130	if (vma->vm_flags & VM_EXEC) {
131		unsigned long addr = (unsigned long)kaddr;
132		if (icache_is_vipt_aliasing())
133			flush_icache_alias(page_to_pfn(page), uaddr, len);
134		else
135			__cpuc_coherent_kern_range(addr, addr + len);
136		if (cache_ops_need_broadcast())
137			smp_call_function(flush_ptrace_access_other,
138					  NULL, 1);
139	}
140}
141
142/*
143 * Copy user data from/to a page which is mapped into a different
144 * processes address space.  Really, we want to allow our "user
145 * space" model to handle this.
146 *
147 * Note that this code needs to run on the current CPU.
148 */
149void copy_to_user_page(struct vm_area_struct *vma, struct page *page,
150		       unsigned long uaddr, void *dst, const void *src,
151		       unsigned long len)
152{
153#ifdef CONFIG_SMP
154	preempt_disable();
155#endif
156	memcpy(dst, src, len);
157	flush_ptrace_access(vma, page, uaddr, dst, len);
158#ifdef CONFIG_SMP
159	preempt_enable();
160#endif
161}
162
163void __flush_dcache_page(struct address_space *mapping, struct page *page)
164{
165	/*
166	 * Writeback any data associated with the kernel mapping of this
167	 * page.  This ensures that data in the physical page is mutually
168	 * coherent with the kernels mapping.
169	 */
170	if (!PageHighMem(page)) {
171		__cpuc_flush_dcache_area(page_address(page), PAGE_SIZE);
172	} else {
173		void *addr = kmap_high_get(page);
174		if (addr) {
175			__cpuc_flush_dcache_area(addr, PAGE_SIZE);
176			kunmap_high(page);
177		} else if (cache_is_vipt()) {
178			/* unmapped pages might still be cached */
179			addr = kmap_atomic(page);
180			__cpuc_flush_dcache_area(addr, PAGE_SIZE);
181			kunmap_atomic(addr);
182		}
183	}
184
185	/*
186	 * If this is a page cache page, and we have an aliasing VIPT cache,
187	 * we only need to do one flush - which would be at the relevant
188	 * userspace colour, which is congruent with page->index.
189	 */
190	if (mapping && cache_is_vipt_aliasing())
191		flush_pfn_alias(page_to_pfn(page),
192				page->index << PAGE_CACHE_SHIFT);
193}
194
195static void __flush_dcache_aliases(struct address_space *mapping, struct page *page)
196{
197	struct mm_struct *mm = current->active_mm;
198	struct vm_area_struct *mpnt;
199	struct prio_tree_iter iter;
200	pgoff_t pgoff;
201
202	/*
203	 * There are possible user space mappings of this page:
204	 * - VIVT cache: we need to also write back and invalidate all user
205	 *   data in the current VM view associated with this page.
206	 * - aliasing VIPT: we only need to find one mapping of this page.
207	 */
208	pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
209
210	flush_dcache_mmap_lock(mapping);
211	vma_prio_tree_foreach(mpnt, &iter, &mapping->i_mmap, pgoff, pgoff) {
212		unsigned long offset;
213
214		/*
215		 * If this VMA is not in our MM, we can ignore it.
216		 */
217		if (mpnt->vm_mm != mm)
218			continue;
219		if (!(mpnt->vm_flags & VM_MAYSHARE))
220			continue;
221		offset = (pgoff - mpnt->vm_pgoff) << PAGE_SHIFT;
222		flush_cache_page(mpnt, mpnt->vm_start + offset, page_to_pfn(page));
223	}
224	flush_dcache_mmap_unlock(mapping);
225}
226
227#if __LINUX_ARM_ARCH__ >= 6
228void __sync_icache_dcache(pte_t pteval)
229{
230	unsigned long pfn;
231	struct page *page;
232	struct address_space *mapping;
233
234	if (!pte_present_user(pteval))
235		return;
236	if (cache_is_vipt_nonaliasing() && !pte_exec(pteval))
237		/* only flush non-aliasing VIPT caches for exec mappings */
238		return;
239	pfn = pte_pfn(pteval);
240	if (!pfn_valid(pfn))
241		return;
242
243	page = pfn_to_page(pfn);
244	if (cache_is_vipt_aliasing())
245		mapping = page_mapping(page);
246	else
247		mapping = NULL;
248
249	if (!test_and_set_bit(PG_dcache_clean, &page->flags))
250		__flush_dcache_page(mapping, page);
251
252	if (pte_exec(pteval))
253		__flush_icache_all();
254}
255#endif
256
257/*
258 * Ensure cache coherency between kernel mapping and userspace mapping
259 * of this page.
260 *
261 * We have three cases to consider:
262 *  - VIPT non-aliasing cache: fully coherent so nothing required.
263 *  - VIVT: fully aliasing, so we need to handle every alias in our
264 *          current VM view.
265 *  - VIPT aliasing: need to handle one alias in our current VM view.
266 *
267 * If we need to handle aliasing:
268 *  If the page only exists in the page cache and there are no user
269 *  space mappings, we can be lazy and remember that we may have dirty
270 *  kernel cache lines for later.  Otherwise, we assume we have
271 *  aliasing mappings.
272 *
273 * Note that we disable the lazy flush for SMP configurations where
274 * the cache maintenance operations are not automatically broadcasted.
275 */
276void flush_dcache_page(struct page *page)
277{
278	struct address_space *mapping;
279
280	/*
281	 * The zero page is never written to, so never has any dirty
282	 * cache lines, and therefore never needs to be flushed.
283	 */
284	if (page == ZERO_PAGE(0))
285		return;
286
287	mapping = page_mapping(page);
288
289	if (!cache_ops_need_broadcast() &&
290	    mapping && !mapping_mapped(mapping))
291		clear_bit(PG_dcache_clean, &page->flags);
292	else {
293		__flush_dcache_page(mapping, page);
294		if (mapping && cache_is_vivt())
295			__flush_dcache_aliases(mapping, page);
296		else if (mapping)
297			__flush_icache_all();
298		set_bit(PG_dcache_clean, &page->flags);
299	}
300}
301EXPORT_SYMBOL(flush_dcache_page);
302
303/*
304 * Flush an anonymous page so that users of get_user_pages()
305 * can safely access the data.  The expected sequence is:
306 *
307 *  get_user_pages()
308 *    -> flush_anon_page
309 *  memcpy() to/from page
310 *  if written to page, flush_dcache_page()
311 */
312void __flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
313{
314	unsigned long pfn;
315
316	/* VIPT non-aliasing caches need do nothing */
317	if (cache_is_vipt_nonaliasing())
318		return;
319
320	/*
321	 * Write back and invalidate userspace mapping.
322	 */
323	pfn = page_to_pfn(page);
324	if (cache_is_vivt()) {
325		flush_cache_page(vma, vmaddr, pfn);
326	} else {
327		/*
328		 * For aliasing VIPT, we can flush an alias of the
329		 * userspace address only.
330		 */
331		flush_pfn_alias(pfn, vmaddr);
332		__flush_icache_all();
333	}
334
335	/*
336	 * Invalidate kernel mapping.  No data should be contained
337	 * in this mapping of the page.  FIXME: this is overkill
338	 * since we actually ask for a write-back and invalidate.
339	 */
340	__cpuc_flush_dcache_area(page_address(page), PAGE_SIZE);
341}
342