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cacheflush.h
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1 #ifndef _ASM_X86_CACHEFLUSH_H
2 #define _ASM_X86_CACHEFLUSH_H
3 
4 /* Caches aren't brain-dead on the intel. */
6 #include <asm/special_insns.h>
7 
8 #ifdef CONFIG_X86_PAT
9 /*
10  * X86 PAT uses page flags WC and Uncached together to keep track of
11  * memory type of pages that have backing page struct. X86 PAT supports 3
12  * different memory types, _PAGE_CACHE_WB, _PAGE_CACHE_WC and
13  * _PAGE_CACHE_UC_MINUS and fourth state where page's memory type has not
14  * been changed from its default (value of -1 used to denote this).
15  * Note we do not support _PAGE_CACHE_UC here.
16  */
17 
18 #define _PGMT_DEFAULT 0
19 #define _PGMT_WC (1UL << PG_arch_1)
20 #define _PGMT_UC_MINUS (1UL << PG_uncached)
21 #define _PGMT_WB (1UL << PG_uncached | 1UL << PG_arch_1)
22 #define _PGMT_MASK (1UL << PG_uncached | 1UL << PG_arch_1)
23 #define _PGMT_CLEAR_MASK (~_PGMT_MASK)
24 
25 static inline unsigned long get_page_memtype(struct page *pg)
26 {
27  unsigned long pg_flags = pg->flags & _PGMT_MASK;
28 
29  if (pg_flags == _PGMT_DEFAULT)
30  return -1;
31  else if (pg_flags == _PGMT_WC)
32  return _PAGE_CACHE_WC;
33  else if (pg_flags == _PGMT_UC_MINUS)
34  return _PAGE_CACHE_UC_MINUS;
35  else
36  return _PAGE_CACHE_WB;
37 }
38 
39 static inline void set_page_memtype(struct page *pg, unsigned long memtype)
40 {
41  unsigned long memtype_flags = _PGMT_DEFAULT;
42  unsigned long old_flags;
43  unsigned long new_flags;
44 
45  switch (memtype) {
46  case _PAGE_CACHE_WC:
47  memtype_flags = _PGMT_WC;
48  break;
50  memtype_flags = _PGMT_UC_MINUS;
51  break;
52  case _PAGE_CACHE_WB:
53  memtype_flags = _PGMT_WB;
54  break;
55  }
56 
57  do {
58  old_flags = pg->flags;
59  new_flags = (old_flags & _PGMT_CLEAR_MASK) | memtype_flags;
60  } while (cmpxchg(&pg->flags, old_flags, new_flags) != old_flags);
61 }
62 #else
63 static inline unsigned long get_page_memtype(struct page *pg) { return -1; }
64 static inline void set_page_memtype(struct page *pg, unsigned long memtype) { }
65 #endif
66 
67 /*
68  * The set_memory_* API can be used to change various attributes of a virtual
69  * address range. The attributes include:
70  * Cachability : UnCached, WriteCombining, WriteBack
71  * Executability : eXeutable, NoteXecutable
72  * Read/Write : ReadOnly, ReadWrite
73  * Presence : NotPresent
74  *
75  * Within a category, the attributes are mutually exclusive.
76  *
77  * The implementation of this API will take care of various aspects that
78  * are associated with changing such attributes, such as:
79  * - Flushing TLBs
80  * - Flushing CPU caches
81  * - Making sure aliases of the memory behind the mapping don't violate
82  * coherency rules as defined by the CPU in the system.
83  *
84  * What this API does not do:
85  * - Provide exclusion between various callers - including callers that
86  * operation on other mappings of the same physical page
87  * - Restore default attributes when a page is freed
88  * - Guarantee that mappings other than the requested one are
89  * in any state, other than that these do not violate rules for
90  * the CPU you have. Do not depend on any effects on other mappings,
91  * CPUs other than the one you have may have more relaxed rules.
92  * The caller is required to take care of these.
93  */
94 
95 int _set_memory_uc(unsigned long addr, int numpages);
96 int _set_memory_wc(unsigned long addr, int numpages);
97 int _set_memory_wb(unsigned long addr, int numpages);
98 int set_memory_uc(unsigned long addr, int numpages);
99 int set_memory_wc(unsigned long addr, int numpages);
100 int set_memory_wb(unsigned long addr, int numpages);
101 int set_memory_x(unsigned long addr, int numpages);
102 int set_memory_nx(unsigned long addr, int numpages);
103 int set_memory_ro(unsigned long addr, int numpages);
104 int set_memory_rw(unsigned long addr, int numpages);
105 int set_memory_np(unsigned long addr, int numpages);
106 int set_memory_4k(unsigned long addr, int numpages);
107 
108 int set_memory_array_uc(unsigned long *addr, int addrinarray);
109 int set_memory_array_wc(unsigned long *addr, int addrinarray);
110 int set_memory_array_wb(unsigned long *addr, int addrinarray);
111 
112 int set_pages_array_uc(struct page **pages, int addrinarray);
113 int set_pages_array_wc(struct page **pages, int addrinarray);
114 int set_pages_array_wb(struct page **pages, int addrinarray);
115 
116 /*
117  * For legacy compatibility with the old APIs, a few functions
118  * are provided that work on a "struct page".
119  * These functions operate ONLY on the 1:1 kernel mapping of the
120  * memory that the struct page represents, and internally just
121  * call the set_memory_* function. See the description of the
122  * set_memory_* function for more details on conventions.
123  *
124  * These APIs should be considered *deprecated* and are likely going to
125  * be removed in the future.
126  * The reason for this is the implicit operation on the 1:1 mapping only,
127  * making this not a generally useful API.
128  *
129  * Specifically, many users of the old APIs had a virtual address,
130  * called virt_to_page() or vmalloc_to_page() on that address to
131  * get a struct page* that the old API required.
132  * To convert these cases, use set_memory_*() on the original
133  * virtual address, do not use these functions.
134  */
135 
136 int set_pages_uc(struct page *page, int numpages);
137 int set_pages_wb(struct page *page, int numpages);
138 int set_pages_x(struct page *page, int numpages);
139 int set_pages_nx(struct page *page, int numpages);
140 int set_pages_ro(struct page *page, int numpages);
141 int set_pages_rw(struct page *page, int numpages);
142 
143 
144 void clflush_cache_range(void *addr, unsigned int size);
145 
146 #ifdef CONFIG_DEBUG_RODATA
147 void mark_rodata_ro(void);
148 extern const int rodata_test_data;
149 extern int kernel_set_to_readonly;
150 void set_kernel_text_rw(void);
151 void set_kernel_text_ro(void);
152 #else
153 static inline void set_kernel_text_rw(void) { }
154 static inline void set_kernel_text_ro(void) { }
155 #endif
156 
157 #ifdef CONFIG_DEBUG_RODATA_TEST
158 int rodata_test(void);
159 #else
160 static inline int rodata_test(void)
161 {
162  return 0;
163 }
164 #endif
165 
166 #endif /* _ASM_X86_CACHEFLUSH_H */