1/*
2 * arch/xtensa/mm/cache.c
3 *
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License. See the file "COPYING" in the main directory of this archive
6 * for more details.
7 *
8 * Copyright (C) 2001-2006 Tensilica Inc.
9 *
10 * Chris Zankel <chris@zankel.net>
11 * Joe Taylor
12 * Marc Gauthier
13 *
14 */
15
16#include <linux/init.h>
17#include <linux/signal.h>
18#include <linux/sched.h>
19#include <linux/kernel.h>
20#include <linux/errno.h>
21#include <linux/string.h>
22#include <linux/types.h>
23#include <linux/ptrace.h>
24#include <linux/memblock.h>
25#include <linux/swap.h>
26#include <linux/pagemap.h>
27#include <linux/pgtable.h>
28
29#include <asm/bootparam.h>
30#include <asm/mmu_context.h>
31#include <asm/tlb.h>
32#include <asm/tlbflush.h>
33#include <asm/page.h>
34
35/*
36 * Note:
37 * The kernel provides one architecture bit PG_arch_1 in the page flags that
38 * can be used for cache coherency.
39 *
40 * I$-D$ coherency.
41 *
42 * The Xtensa architecture doesn't keep the instruction cache coherent with
43 * the data cache. We use the architecture bit to indicate if the caches
44 * are coherent. The kernel clears this bit whenever a page is added to the
45 * page cache. At that time, the caches might not be in sync. We, therefore,
46 * define this flag as 'clean' if set.
47 *
48 * D-cache aliasing.
49 *
50 * With cache aliasing, we have to always flush the cache when pages are
51 * unmapped (see tlb_start_vma(). So, we use this flag to indicate a dirty
52 * page.
53 *
54 *
55 *
56 */
57
58#if (DCACHE_WAY_SIZE > PAGE_SIZE)
59static inline void kmap_invalidate_coherent(struct page *page,
60 unsigned long vaddr)
61{
62 if (!DCACHE_ALIAS_EQ(page_to_phys(page), vaddr)) {
63 unsigned long kvaddr;
64
65 if (!PageHighMem(page)) {
66 kvaddr = (unsigned long)page_to_virt(page);
67
68 __invalidate_dcache_page(kvaddr);
69 } else {
70 kvaddr = TLBTEMP_BASE_1 +
71 (page_to_phys(page) & DCACHE_ALIAS_MASK);
72
73 preempt_disable();
74 __invalidate_dcache_page_alias(kvaddr,
75 page_to_phys(page));
76 preempt_enable();
77 }
78 }
79}
80
81static inline void *coherent_kvaddr(struct page *page, unsigned long base,
82 unsigned long vaddr, unsigned long *paddr)
83{
84 *paddr = page_to_phys(page);
85 return (void *)(base + (vaddr & DCACHE_ALIAS_MASK));
86}
87
88void clear_user_highpage(struct page *page, unsigned long vaddr)
89{
90 struct folio *folio = page_folio(page);
91 unsigned long paddr;
92 void *kvaddr = coherent_kvaddr(page, TLBTEMP_BASE_1, vaddr, &paddr);
93
94 preempt_disable();
95 kmap_invalidate_coherent(page, vaddr);
96 set_bit(PG_arch_1, folio_flags(folio, 0));
97 clear_page_alias(kvaddr, paddr);
98 preempt_enable();
99}
100EXPORT_SYMBOL(clear_user_highpage);
101
102void copy_user_highpage(struct page *dst, struct page *src,
103 unsigned long vaddr, struct vm_area_struct *vma)
104{
105 struct folio *folio = page_folio(dst);
106 unsigned long dst_paddr, src_paddr;
107 void *dst_vaddr = coherent_kvaddr(dst, TLBTEMP_BASE_1, vaddr,
108 &dst_paddr);
109 void *src_vaddr = coherent_kvaddr(src, TLBTEMP_BASE_2, vaddr,
110 &src_paddr);
111
112 preempt_disable();
113 kmap_invalidate_coherent(dst, vaddr);
114 set_bit(PG_arch_1, folio_flags(folio, 0));
115 copy_page_alias(dst_vaddr, src_vaddr, dst_paddr, src_paddr);
116 preempt_enable();
117}
118EXPORT_SYMBOL(copy_user_highpage);
119
120/*
121 * Any time the kernel writes to a user page cache page, or it is about to
122 * read from a page cache page this routine is called.
123 *
124 */
125
126void flush_dcache_folio(struct folio *folio)
127{
128 struct address_space *mapping = folio_flush_mapping(folio);
129
130 /*
131 * If we have a mapping but the page is not mapped to user-space
132 * yet, we simply mark this page dirty and defer flushing the
133 * caches until update_mmu().
134 */
135
136 if (mapping && !mapping_mapped(mapping)) {
137 if (!test_bit(PG_arch_1, &folio->flags.f))
138 set_bit(PG_arch_1, &folio->flags.f);
139 return;
140
141 } else {
142 unsigned long phys = folio_pfn(folio) * PAGE_SIZE;
143 unsigned long temp = folio_pos(folio);
144 unsigned int i, nr = folio_nr_pages(folio);
145 unsigned long alias = !(DCACHE_ALIAS_EQ(temp, phys));
146 unsigned long virt;
147
148 /*
149 * Flush the page in kernel space and user space.
150 * Note that we can omit that step if aliasing is not
151 * an issue, but we do have to synchronize I$ and D$
152 * if we have a mapping.
153 */
154
155 if (!alias && !mapping)
156 return;
157
158 preempt_disable();
159 for (i = 0; i < nr; i++) {
160 virt = TLBTEMP_BASE_1 + (phys & DCACHE_ALIAS_MASK);
161 __flush_invalidate_dcache_page_alias(virt, phys);
162
163 virt = TLBTEMP_BASE_1 + (temp & DCACHE_ALIAS_MASK);
164
165 if (alias)
166 __flush_invalidate_dcache_page_alias(virt, phys);
167
168 if (mapping)
169 __invalidate_icache_page_alias(virt, phys);
170 phys += PAGE_SIZE;
171 temp += PAGE_SIZE;
172 }
173 preempt_enable();
174 }
175
176 /* There shouldn't be an entry in the cache for this page anymore. */
177}
178EXPORT_SYMBOL(flush_dcache_folio);
179
180/*
181 * For now, flush the whole cache. FIXME??
182 */
183
184void local_flush_cache_range(struct vm_area_struct *vma,
185 unsigned long start, unsigned long end)
186{
187 __flush_invalidate_dcache_all();
188 __invalidate_icache_all();
189}
190EXPORT_SYMBOL(local_flush_cache_range);
191
192/*
193 * Remove any entry in the cache for this page.
194 *
195 * Note that this function is only called for user pages, so use the
196 * alias versions of the cache flush functions.
197 */
198
199void local_flush_cache_page(struct vm_area_struct *vma, unsigned long address,
200 unsigned long pfn)
201{
202 /* Note that we have to use the 'alias' address to avoid multi-hit */
203
204 unsigned long phys = page_to_phys(pfn_to_page(pfn));
205 unsigned long virt = TLBTEMP_BASE_1 + (address & DCACHE_ALIAS_MASK);
206
207 preempt_disable();
208 __flush_invalidate_dcache_page_alias(virt, phys);
209 __invalidate_icache_page_alias(virt, phys);
210 preempt_enable();
211}
212EXPORT_SYMBOL(local_flush_cache_page);
213
214#endif /* DCACHE_WAY_SIZE > PAGE_SIZE */
215
216void update_mmu_cache_range(struct vm_fault *vmf, struct vm_area_struct *vma,
217 unsigned long addr, pte_t *ptep, unsigned int nr)
218{
219 unsigned long pfn = pte_pfn(pte: *ptep);
220 struct folio *folio;
221 unsigned int i;
222
223 if (!pfn_valid(pfn))
224 return;
225
226 folio = page_folio(pfn_to_page(pfn));
227
228 /* Invalidate old entries in TLBs */
229 for (i = 0; i < nr; i++)
230 flush_tlb_page(vma, a: addr + i * PAGE_SIZE);
231 nr = folio_nr_pages(folio);
232
233#if (DCACHE_WAY_SIZE > PAGE_SIZE)
234
235 if (!folio_test_reserved(folio) && test_bit(PG_arch_1, &folio->flags.f)) {
236 unsigned long phys = folio_pfn(folio) * PAGE_SIZE;
237 unsigned long tmp;
238
239 preempt_disable();
240 for (i = 0; i < nr; i++) {
241 tmp = TLBTEMP_BASE_1 + (phys & DCACHE_ALIAS_MASK);
242 __flush_invalidate_dcache_page_alias(tmp, phys);
243 tmp = TLBTEMP_BASE_1 + (addr & DCACHE_ALIAS_MASK);
244 __flush_invalidate_dcache_page_alias(tmp, phys);
245 __invalidate_icache_page_alias(tmp, phys);
246 phys += PAGE_SIZE;
247 }
248 preempt_enable();
249
250 clear_bit(PG_arch_1, &folio->flags.f);
251 }
252#else
253 if (!folio_test_reserved(folio) && !test_bit(PG_arch_1, &folio->flags.f)
254 && (vma->vm_flags & VM_EXEC) != 0) {
255 for (i = 0; i < nr; i++) {
256 void *paddr = kmap_local_folio(folio, offset: i * PAGE_SIZE);
257 __flush_dcache_page((unsigned long)paddr);
258 __invalidate_icache_page((unsigned long)paddr);
259 kunmap_local(paddr);
260 }
261 set_bit(nr: PG_arch_1, addr: &folio->flags.f);
262 }
263#endif
264}
265
266/*
267 * access_process_vm() has called get_user_pages(), which has done a
268 * flush_dcache_page() on the page.
269 */
270
271#if (DCACHE_WAY_SIZE > PAGE_SIZE)
272
273void copy_to_user_page(struct vm_area_struct *vma, struct page *page,
274 unsigned long vaddr, void *dst, const void *src,
275 unsigned long len)
276{
277 unsigned long phys = page_to_phys(page);
278 unsigned long alias = !(DCACHE_ALIAS_EQ(vaddr, phys));
279
280 /* Flush and invalidate user page if aliased. */
281
282 if (alias) {
283 unsigned long t = TLBTEMP_BASE_1 + (vaddr & DCACHE_ALIAS_MASK);
284 preempt_disable();
285 __flush_invalidate_dcache_page_alias(t, phys);
286 preempt_enable();
287 }
288
289 /* Copy data */
290
291 memcpy(dst, src, len);
292
293 /*
294 * Flush and invalidate kernel page if aliased and synchronize
295 * data and instruction caches for executable pages.
296 */
297
298 if (alias) {
299 unsigned long t = TLBTEMP_BASE_1 + (vaddr & DCACHE_ALIAS_MASK);
300
301 preempt_disable();
302 __flush_invalidate_dcache_range((unsigned long) dst, len);
303 if ((vma->vm_flags & VM_EXEC) != 0)
304 __invalidate_icache_page_alias(t, phys);
305 preempt_enable();
306
307 } else if ((vma->vm_flags & VM_EXEC) != 0) {
308 __flush_dcache_range((unsigned long)dst,len);
309 __invalidate_icache_range((unsigned long) dst, len);
310 }
311}
312
313extern void copy_from_user_page(struct vm_area_struct *vma, struct page *page,
314 unsigned long vaddr, void *dst, const void *src,
315 unsigned long len)
316{
317 unsigned long phys = page_to_phys(page);
318 unsigned long alias = !(DCACHE_ALIAS_EQ(vaddr, phys));
319
320 /*
321 * Flush user page if aliased.
322 * (Note: a simply flush would be sufficient)
323 */
324
325 if (alias) {
326 unsigned long t = TLBTEMP_BASE_1 + (vaddr & DCACHE_ALIAS_MASK);
327 preempt_disable();
328 __flush_invalidate_dcache_page_alias(t, phys);
329 preempt_enable();
330 }
331
332 memcpy(dst, src, len);
333}
334
335#endif
336

source code of linux/arch/xtensa/mm/cache.c