1 /* Invalidate icache when dcache doesn't need invalidation as it's in
2 * write-through mode
3 *
4 * Copyright (C) 2010 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public Licence
9 * as published by the Free Software Foundation; either version
10 * 2 of the Licence, or (at your option) any later version.
11 */
12 #include <linux/module.h>
13 #include <linux/mm.h>
14 #include <asm/cacheflush.h>
15 #include <asm/smp.h>
16 #include "cache-smp.h"
17
18 /**
19 * flush_icache_page_range - Flush dcache and invalidate icache for part of a
20 * single page
21 * @start: The starting virtual address of the page part.
22 * @end: The ending virtual address of the page part.
23 *
24 * Invalidate the icache for part of a single page, as determined by the
25 * virtual addresses given. The page must be in the paged area. The dcache is
26 * not flushed as the cache must be in write-through mode to get here.
27 */
flush_icache_page_range(unsigned long start,unsigned long end)28 static void flush_icache_page_range(unsigned long start, unsigned long end)
29 {
30 unsigned long addr, size, off;
31 struct page *page;
32 pgd_t *pgd;
33 pud_t *pud;
34 pmd_t *pmd;
35 pte_t *ppte, pte;
36
37 /* work out how much of the page to flush */
38 off = start & ~PAGE_MASK;
39 size = end - start;
40
41 /* get the physical address the page is mapped to from the page
42 * tables */
43 pgd = pgd_offset(current->mm, start);
44 if (!pgd || !pgd_val(*pgd))
45 return;
46
47 pud = pud_offset(pgd, start);
48 if (!pud || !pud_val(*pud))
49 return;
50
51 pmd = pmd_offset(pud, start);
52 if (!pmd || !pmd_val(*pmd))
53 return;
54
55 ppte = pte_offset_map(pmd, start);
56 if (!ppte)
57 return;
58 pte = *ppte;
59 pte_unmap(ppte);
60
61 if (pte_none(pte))
62 return;
63
64 page = pte_page(pte);
65 if (!page)
66 return;
67
68 addr = page_to_phys(page);
69
70 /* invalidate the icache coverage on that region */
71 mn10300_local_icache_inv_range2(addr + off, size);
72 smp_cache_call(SMP_ICACHE_INV_RANGE, start, end);
73 }
74
75 /**
76 * flush_icache_range - Globally flush dcache and invalidate icache for region
77 * @start: The starting virtual address of the region.
78 * @end: The ending virtual address of the region.
79 *
80 * This is used by the kernel to globally flush some code it has just written
81 * from the dcache back to RAM and then to globally invalidate the icache over
82 * that region so that that code can be run on all CPUs in the system.
83 */
flush_icache_range(unsigned long start,unsigned long end)84 void flush_icache_range(unsigned long start, unsigned long end)
85 {
86 unsigned long start_page, end_page;
87 unsigned long flags;
88
89 flags = smp_lock_cache();
90
91 if (end > 0x80000000UL) {
92 /* addresses above 0xa0000000 do not go through the cache */
93 if (end > 0xa0000000UL) {
94 end = 0xa0000000UL;
95 if (start >= end)
96 goto done;
97 }
98
99 /* kernel addresses between 0x80000000 and 0x9fffffff do not
100 * require page tables, so we just map such addresses
101 * directly */
102 start_page = (start >= 0x80000000UL) ? start : 0x80000000UL;
103 mn10300_icache_inv_range(start_page, end);
104 smp_cache_call(SMP_ICACHE_INV_RANGE, start, end);
105 if (start_page == start)
106 goto done;
107 end = start_page;
108 }
109
110 start_page = start & PAGE_MASK;
111 end_page = (end - 1) & PAGE_MASK;
112
113 if (start_page == end_page) {
114 /* the first and last bytes are on the same page */
115 flush_icache_page_range(start, end);
116 } else if (start_page + 1 == end_page) {
117 /* split over two virtually contiguous pages */
118 flush_icache_page_range(start, end_page);
119 flush_icache_page_range(end_page, end);
120 } else {
121 /* more than 2 pages; just flush the entire cache */
122 mn10300_local_icache_inv();
123 smp_cache_call(SMP_ICACHE_INV, 0, 0);
124 }
125
126 done:
127 smp_unlock_cache(flags);
128 }
129 EXPORT_SYMBOL(flush_icache_range);
130