1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_X86_SET_MEMORY_H
3 #define _ASM_X86_SET_MEMORY_H
4
5 #include <asm/page.h>
6 #include <asm-generic/set_memory.h>
7
8 /*
9 * The set_memory_* API can be used to change various attributes of a virtual
10 * address range. The attributes include:
11 * Cachability : UnCached, WriteCombining, WriteThrough, WriteBack
12 * Executability : eXeutable, NoteXecutable
13 * Read/Write : ReadOnly, ReadWrite
14 * Presence : NotPresent
15 * Encryption : Encrypted, Decrypted
16 *
17 * Within a category, the attributes are mutually exclusive.
18 *
19 * The implementation of this API will take care of various aspects that
20 * are associated with changing such attributes, such as:
21 * - Flushing TLBs
22 * - Flushing CPU caches
23 * - Making sure aliases of the memory behind the mapping don't violate
24 * coherency rules as defined by the CPU in the system.
25 *
26 * What this API does not do:
27 * - Provide exclusion between various callers - including callers that
28 * operation on other mappings of the same physical page
29 * - Restore default attributes when a page is freed
30 * - Guarantee that mappings other than the requested one are
31 * in any state, other than that these do not violate rules for
32 * the CPU you have. Do not depend on any effects on other mappings,
33 * CPUs other than the one you have may have more relaxed rules.
34 * The caller is required to take care of these.
35 */
36
37 int _set_memory_uc(unsigned long addr, int numpages);
38 int _set_memory_wc(unsigned long addr, int numpages);
39 int _set_memory_wt(unsigned long addr, int numpages);
40 int _set_memory_wb(unsigned long addr, int numpages);
41 int set_memory_uc(unsigned long addr, int numpages);
42 int set_memory_wc(unsigned long addr, int numpages);
43 int set_memory_wb(unsigned long addr, int numpages);
44 int set_memory_np(unsigned long addr, int numpages);
45 int set_memory_4k(unsigned long addr, int numpages);
46 int set_memory_encrypted(unsigned long addr, int numpages);
47 int set_memory_decrypted(unsigned long addr, int numpages);
48 int set_memory_np_noalias(unsigned long addr, int numpages);
49
50 int set_pages_array_uc(struct page **pages, int addrinarray);
51 int set_pages_array_wc(struct page **pages, int addrinarray);
52 int set_pages_array_wt(struct page **pages, int addrinarray);
53 int set_pages_array_wb(struct page **pages, int addrinarray);
54
55 /*
56 * For legacy compatibility with the old APIs, a few functions
57 * are provided that work on a "struct page".
58 * These functions operate ONLY on the 1:1 kernel mapping of the
59 * memory that the struct page represents, and internally just
60 * call the set_memory_* function. See the description of the
61 * set_memory_* function for more details on conventions.
62 *
63 * These APIs should be considered *deprecated* and are likely going to
64 * be removed in the future.
65 * The reason for this is the implicit operation on the 1:1 mapping only,
66 * making this not a generally useful API.
67 *
68 * Specifically, many users of the old APIs had a virtual address,
69 * called virt_to_page() or vmalloc_to_page() on that address to
70 * get a struct page* that the old API required.
71 * To convert these cases, use set_memory_*() on the original
72 * virtual address, do not use these functions.
73 */
74
75 int set_pages_uc(struct page *page, int numpages);
76 int set_pages_wb(struct page *page, int numpages);
77 int set_pages_ro(struct page *page, int numpages);
78 int set_pages_rw(struct page *page, int numpages);
79
80 int set_direct_map_invalid_noflush(struct page *page);
81 int set_direct_map_default_noflush(struct page *page);
82
83 extern int kernel_set_to_readonly;
84 void set_kernel_text_rw(void);
85 void set_kernel_text_ro(void);
86
87 #ifdef CONFIG_X86_64
88 /*
89 * Prevent speculative access to the page by either unmapping
90 * it (if we do not require access to any part of the page) or
91 * marking it uncacheable (if we want to try to retrieve data
92 * from non-poisoned lines in the page).
93 */
94 static inline int set_mce_nospec(unsigned long pfn, bool unmap)
95 {
96 unsigned long decoy_addr;
97 int rc;
98
99 /*
100 * We would like to just call:
101 * set_memory_XX((unsigned long)pfn_to_kaddr(pfn), 1);
102 * but doing that would radically increase the odds of a
103 * speculative access to the poison page because we'd have
104 * the virtual address of the kernel 1:1 mapping sitting
105 * around in registers.
106 * Instead we get tricky. We create a non-canonical address
107 * that looks just like the one we want, but has bit 63 flipped.
108 * This relies on set_memory_XX() properly sanitizing any __pa()
109 * results with __PHYSICAL_MASK or PTE_PFN_MASK.
110 */
111 decoy_addr = (pfn << PAGE_SHIFT) + (PAGE_OFFSET ^ BIT(63));
112
113 if (unmap)
114 rc = set_memory_np(decoy_addr, 1);
115 else
116 rc = set_memory_uc(decoy_addr, 1);
117 if (rc)
118 pr_warn("Could not invalidate pfn=0x%lx from 1:1 map\n", pfn);
119 return rc;
120 }
121 #define set_mce_nospec set_mce_nospec
122
123 /* Restore full speculative operation to the pfn. */
124 static inline int clear_mce_nospec(unsigned long pfn)
125 {
126 return set_memory_wb((unsigned long) pfn_to_kaddr(pfn), 1);
127 }
128 #define clear_mce_nospec clear_mce_nospec
129 #else
130 /*
131 * Few people would run a 32-bit kernel on a machine that supports
132 * recoverable errors because they have too much memory to boot 32-bit.
133 */
134 #endif
135
136 #endif /* _ASM_X86_SET_MEMORY_H */