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/bootmem.h>
 25#include <linux/swap.h>
 26#include <linux/pagemap.h>
 27
 28#include <asm/bootparam.h>
 29#include <asm/mmu_context.h>
 30#include <asm/tlb.h>
 31#include <asm/tlbflush.h>
 32#include <asm/page.h>
 33#include <asm/pgalloc.h>
 34#include <asm/pgtable.h>
 35
 36//#define printd(x...) printk(x)
 37#define printd(x...) do { } while(0)
 38
 39/* 
 40 * Note:
 41 * The kernel provides one architecture bit PG_arch_1 in the page flags that 
 42 * can be used for cache coherency.
 43 *
 44 * I$-D$ coherency.
 45 *
 46 * The Xtensa architecture doesn't keep the instruction cache coherent with
 47 * the data cache. We use the architecture bit to indicate if the caches
 48 * are coherent. The kernel clears this bit whenever a page is added to the
 49 * page cache. At that time, the caches might not be in sync. We, therefore,
 50 * define this flag as 'clean' if set.
 51 *
 52 * D-cache aliasing.
 53 *
 54 * With cache aliasing, we have to always flush the cache when pages are
 55 * unmapped (see tlb_start_vma(). So, we use this flag to indicate a dirty
 56 * page.
 57 * 
 58 *
 59 *
 60 */
 61
 62#if (DCACHE_WAY_SIZE > PAGE_SIZE) && XCHAL_DCACHE_IS_WRITEBACK
 63
 64/*
 65 * Any time the kernel writes to a user page cache page, or it is about to
 66 * read from a page cache page this routine is called.
 67 *
 68 */
 69
 70void flush_dcache_page(struct page *page)
 71{
 72	struct address_space *mapping = page_mapping(page);
 73
 74	/*
 75	 * If we have a mapping but the page is not mapped to user-space
 76	 * yet, we simply mark this page dirty and defer flushing the 
 77	 * caches until update_mmu().
 78	 */
 79
 80	if (mapping && !mapping_mapped(mapping)) {
 81		if (!test_bit(PG_arch_1, &page->flags))
 82			set_bit(PG_arch_1, &page->flags);
 83		return;
 84
 85	} else {
 86
 87		unsigned long phys = page_to_phys(page);
 88		unsigned long temp = page->index << PAGE_SHIFT;
 89		unsigned long alias = !(DCACHE_ALIAS_EQ(temp, phys));
 90		unsigned long virt;
 91
 92		/* 
 93		 * Flush the page in kernel space and user space.
 94		 * Note that we can omit that step if aliasing is not
 95		 * an issue, but we do have to synchronize I$ and D$
 96		 * if we have a mapping.
 97		 */
 98
 99		if (!alias && !mapping)
100			return;
101
102		__flush_invalidate_dcache_page((long)page_address(page));
103
104		virt = TLBTEMP_BASE_1 + (temp & DCACHE_ALIAS_MASK);
105
106		if (alias)
107			__flush_invalidate_dcache_page_alias(virt, phys);
108
109		if (mapping)
110			__invalidate_icache_page_alias(virt, phys);
111	}
112
113	/* There shouldn't be an entry in the cache for this page anymore. */
114}
115
116
117/*
118 * For now, flush the whole cache. FIXME??
119 */
120
121void flush_cache_range(struct vm_area_struct* vma, 
122		       unsigned long start, unsigned long end)
123{
124	__flush_invalidate_dcache_all();
125	__invalidate_icache_all();
126}
127
128/* 
129 * Remove any entry in the cache for this page. 
130 *
131 * Note that this function is only called for user pages, so use the
132 * alias versions of the cache flush functions.
133 */
134
135void flush_cache_page(struct vm_area_struct* vma, unsigned long address,
136    		      unsigned long pfn)
137{
138	/* Note that we have to use the 'alias' address to avoid multi-hit */
139
140	unsigned long phys = page_to_phys(pfn_to_page(pfn));
141	unsigned long virt = TLBTEMP_BASE_1 + (address & DCACHE_ALIAS_MASK);
142
143	__flush_invalidate_dcache_page_alias(virt, phys);
144	__invalidate_icache_page_alias(virt, phys);
145}
146
147#endif
148
149void
150update_mmu_cache(struct vm_area_struct * vma, unsigned long addr, pte_t *ptep)
151{
152	unsigned long pfn = pte_pfn(*ptep);
153	struct page *page;
154
155	if (!pfn_valid(pfn))
156		return;
157
158	page = pfn_to_page(pfn);
159
160	/* Invalidate old entry in TLBs */
161
162	invalidate_itlb_mapping(addr);
163	invalidate_dtlb_mapping(addr);
164
165#if (DCACHE_WAY_SIZE > PAGE_SIZE) && XCHAL_DCACHE_IS_WRITEBACK
166
167	if (!PageReserved(page) && test_bit(PG_arch_1, &page->flags)) {
168
169		unsigned long vaddr = TLBTEMP_BASE_1 + (addr & DCACHE_ALIAS_MASK);
170		unsigned long paddr = (unsigned long) page_address(page);
171		unsigned long phys = page_to_phys(page);
172
173		__flush_invalidate_dcache_page(paddr);
174
175		__flush_invalidate_dcache_page_alias(vaddr, phys);
176		__invalidate_icache_page_alias(vaddr, phys);
177
178		clear_bit(PG_arch_1, &page->flags);
179	}
180#else
181	if (!PageReserved(page) && !test_bit(PG_arch_1, &page->flags)
182	    && (vma->vm_flags & VM_EXEC) != 0) {
183	    	unsigned long paddr = (unsigned long) page_address(page);
184		__flush_dcache_page(paddr);
185		__invalidate_icache_page(paddr);
186		set_bit(PG_arch_1, &page->flags);
187	}
188#endif
189}
190
191/*
192 * access_process_vm() has called get_user_pages(), which has done a
193 * flush_dcache_page() on the page.
194 */
195
196#if (DCACHE_WAY_SIZE > PAGE_SIZE) && XCHAL_DCACHE_IS_WRITEBACK
197
198void copy_to_user_page(struct vm_area_struct *vma, struct page *page, 
199		unsigned long vaddr, void *dst, const void *src,
200		unsigned long len)
201{
202	unsigned long phys = page_to_phys(page);
203	unsigned long alias = !(DCACHE_ALIAS_EQ(vaddr, phys));
204
205	/* Flush and invalidate user page if aliased. */
206
207	if (alias) {
208		unsigned long temp = TLBTEMP_BASE_1 + (vaddr & DCACHE_ALIAS_MASK);
209		__flush_invalidate_dcache_page_alias(temp, phys);
210	}
211
212	/* Copy data */
213	
214	memcpy(dst, src, len);
215
216	/*
217	 * Flush and invalidate kernel page if aliased and synchronize 
218	 * data and instruction caches for executable pages. 
219	 */
220
221	if (alias) {
222		unsigned long temp = TLBTEMP_BASE_1 + (vaddr & DCACHE_ALIAS_MASK);
223
224		__flush_invalidate_dcache_range((unsigned long) dst, len);
225		if ((vma->vm_flags & VM_EXEC) != 0) {
226			__invalidate_icache_page_alias(temp, phys);
227		}
228
229	} else if ((vma->vm_flags & VM_EXEC) != 0) {
230		__flush_dcache_range((unsigned long)dst,len);
231		__invalidate_icache_range((unsigned long) dst, len);
232	}
233}
234
235extern void copy_from_user_page(struct vm_area_struct *vma, struct page *page,
236		unsigned long vaddr, void *dst, const void *src,
237		unsigned long len)
238{
239	unsigned long phys = page_to_phys(page);
240	unsigned long alias = !(DCACHE_ALIAS_EQ(vaddr, phys));
241
242	/*
243	 * Flush user page if aliased. 
244	 * (Note: a simply flush would be sufficient) 
245	 */
246
247	if (alias) {
248		unsigned long temp = TLBTEMP_BASE_1 + (vaddr & DCACHE_ALIAS_MASK);
249		__flush_invalidate_dcache_page_alias(temp, phys);
250	}
251
252	memcpy(dst, src, len);
253}
254
255#endif