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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  */
set_mce_nospec(unsigned long pfn,bool unmap)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. */
clear_mce_nospec(unsigned long 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 */
137