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 */ 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. */ 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