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 * Cacheability : UnCached, WriteCombining, WriteThrough, WriteBack
12 * Executability : eXecutable, 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_prot(unsigned long addr, int numpages, pgprot_t prot);
38 int _set_memory_uc(unsigned long addr, int numpages);
39 int _set_memory_wc(unsigned long addr, int numpages);
40 int _set_memory_wt(unsigned long addr, int numpages);
41 int _set_memory_wb(unsigned long addr, int numpages);
42 int set_memory_uc(unsigned long addr, int numpages);
43 int set_memory_wc(unsigned long addr, int numpages);
44 int set_memory_wb(unsigned long addr, int numpages);
45 int set_memory_np(unsigned long addr, int numpages);
46 int set_memory_4k(unsigned long addr, int numpages);
47 int set_memory_encrypted(unsigned long addr, int numpages);
48 int set_memory_decrypted(unsigned long addr, int numpages);
49 int set_memory_np_noalias(unsigned long addr, int numpages);
50 int set_memory_nonglobal(unsigned long addr, int numpages);
51 int set_memory_global(unsigned long addr, int numpages);
52
53 int set_pages_array_uc(struct page **pages, int addrinarray);
54 int set_pages_array_wc(struct page **pages, int addrinarray);
55 int set_pages_array_wt(struct page **pages, int addrinarray);
56 int set_pages_array_wb(struct page **pages, int addrinarray);
57
58 /*
59 * For legacy compatibility with the old APIs, a few functions
60 * are provided that work on a "struct page".
61 * These functions operate ONLY on the 1:1 kernel mapping of the
62 * memory that the struct page represents, and internally just
63 * call the set_memory_* function. See the description of the
64 * set_memory_* function for more details on conventions.
65 *
66 * These APIs should be considered *deprecated* and are likely going to
67 * be removed in the future.
68 * The reason for this is the implicit operation on the 1:1 mapping only,
69 * making this not a generally useful API.
70 *
71 * Specifically, many users of the old APIs had a virtual address,
72 * called virt_to_page() or vmalloc_to_page() on that address to
73 * get a struct page* that the old API required.
74 * To convert these cases, use set_memory_*() on the original
75 * virtual address, do not use these functions.
76 */
77
78 int set_pages_uc(struct page *page, int numpages);
79 int set_pages_wb(struct page *page, int numpages);
80 int set_pages_ro(struct page *page, int numpages);
81 int set_pages_rw(struct page *page, int numpages);
82
83 int set_direct_map_invalid_noflush(struct page *page);
84 int set_direct_map_default_noflush(struct page *page);
85 bool kernel_page_present(struct page *page);
86
87 extern int kernel_set_to_readonly;
88
89 #ifdef CONFIG_X86_64
90 /*
91 * Prevent speculative access to the page by either unmapping
92 * it (if we do not require access to any part of the page) or
93 * marking it uncacheable (if we want to try to retrieve data
94 * from non-poisoned lines in the page).
95 */
set_mce_nospec(unsigned long pfn,bool unmap)96 static inline int set_mce_nospec(unsigned long pfn, bool unmap)
97 {
98 unsigned long decoy_addr;
99 int rc;
100
101 /*
102 * We would like to just call:
103 * set_memory_XX((unsigned long)pfn_to_kaddr(pfn), 1);
104 * but doing that would radically increase the odds of a
105 * speculative access to the poison page because we'd have
106 * the virtual address of the kernel 1:1 mapping sitting
107 * around in registers.
108 * Instead we get tricky. We create a non-canonical address
109 * that looks just like the one we want, but has bit 63 flipped.
110 * This relies on set_memory_XX() properly sanitizing any __pa()
111 * results with __PHYSICAL_MASK or PTE_PFN_MASK.
112 */
113 decoy_addr = (pfn << PAGE_SHIFT) + (PAGE_OFFSET ^ BIT(63));
114
115 if (unmap)
116 rc = set_memory_np(decoy_addr, 1);
117 else
118 rc = set_memory_uc(decoy_addr, 1);
119 if (rc)
120 pr_warn("Could not invalidate pfn=0x%lx from 1:1 map\n", pfn);
121 return rc;
122 }
123 #define set_mce_nospec set_mce_nospec
124
125 /* Restore full speculative operation to the pfn. */
clear_mce_nospec(unsigned long pfn)126 static inline int clear_mce_nospec(unsigned long pfn)
127 {
128 return set_memory_wb((unsigned long) pfn_to_kaddr(pfn), 1);
129 }
130 #define clear_mce_nospec clear_mce_nospec
131 #else
132 /*
133 * Few people would run a 32-bit kernel on a machine that supports
134 * recoverable errors because they have too much memory to boot 32-bit.
135 */
136 #endif
137
138 #endif /* _ASM_X86_SET_MEMORY_H */
139