1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_X86_SET_MEMORY_H 3 #define _ASM_X86_SET_MEMORY_H 4 5 #include <linux/mm.h> 6 #include <asm/page.h> 7 #include <asm-generic/set_memory.h> 8 9 /* 10 * The set_memory_* API can be used to change various attributes of a virtual 11 * address range. The attributes include: 12 * Cacheability : UnCached, WriteCombining, WriteThrough, WriteBack 13 * Executability : eXecutable, NoteXecutable 14 * Read/Write : ReadOnly, ReadWrite 15 * Presence : NotPresent 16 * Encryption : Encrypted, Decrypted 17 * 18 * Within a category, the attributes are mutually exclusive. 19 * 20 * The implementation of this API will take care of various aspects that 21 * are associated with changing such attributes, such as: 22 * - Flushing TLBs 23 * - Flushing CPU caches 24 * - Making sure aliases of the memory behind the mapping don't violate 25 * coherency rules as defined by the CPU in the system. 26 * 27 * What this API does not do: 28 * - Provide exclusion between various callers - including callers that 29 * operation on other mappings of the same physical page 30 * - Restore default attributes when a page is freed 31 * - Guarantee that mappings other than the requested one are 32 * in any state, other than that these do not violate rules for 33 * the CPU you have. Do not depend on any effects on other mappings, 34 * CPUs other than the one you have may have more relaxed rules. 35 * The caller is required to take care of these. 36 */ 37 38 int __set_memory_prot(unsigned long addr, int numpages, pgprot_t prot); 39 int _set_memory_uc(unsigned long addr, int numpages); 40 int _set_memory_wc(unsigned long addr, int numpages); 41 int _set_memory_wt(unsigned long addr, int numpages); 42 int _set_memory_wb(unsigned long addr, int numpages); 43 int set_memory_uc(unsigned long addr, int numpages); 44 int set_memory_wc(unsigned long addr, int numpages); 45 int set_memory_wb(unsigned long addr, int numpages); 46 int set_memory_np(unsigned long addr, int numpages); 47 int set_memory_4k(unsigned long addr, int numpages); 48 int set_memory_encrypted(unsigned long addr, int numpages); 49 int set_memory_decrypted(unsigned long addr, int numpages); 50 int set_memory_np_noalias(unsigned long addr, int numpages); 51 int set_memory_nonglobal(unsigned long addr, int numpages); 52 int set_memory_global(unsigned long addr, int numpages); 53 54 int set_pages_array_uc(struct page **pages, int addrinarray); 55 int set_pages_array_wc(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 /* SGX pages are not in the 1:1 map */ 102 if (arch_is_platform_page(pfn << PAGE_SHIFT)) 103 return 0; 104 /* 105 * We would like to just call: 106 * set_memory_XX((unsigned long)pfn_to_kaddr(pfn), 1); 107 * but doing that would radically increase the odds of a 108 * speculative access to the poison page because we'd have 109 * the virtual address of the kernel 1:1 mapping sitting 110 * around in registers. 111 * Instead we get tricky. We create a non-canonical address 112 * that looks just like the one we want, but has bit 63 flipped. 113 * This relies on set_memory_XX() properly sanitizing any __pa() 114 * results with __PHYSICAL_MASK or PTE_PFN_MASK. 115 */ 116 decoy_addr = (pfn << PAGE_SHIFT) + (PAGE_OFFSET ^ BIT(63)); 117 118 if (unmap) 119 rc = set_memory_np(decoy_addr, 1); 120 else 121 rc = set_memory_uc(decoy_addr, 1); 122 if (rc) 123 pr_warn("Could not invalidate pfn=0x%lx from 1:1 map\n", pfn); 124 return rc; 125 } 126 #define set_mce_nospec set_mce_nospec 127 128 /* Restore full speculative operation to the pfn. */ 129 static inline int clear_mce_nospec(unsigned long pfn) 130 { 131 return set_memory_wb((unsigned long) pfn_to_kaddr(pfn), 1); 132 } 133 #define clear_mce_nospec clear_mce_nospec 134 #else 135 /* 136 * Few people would run a 32-bit kernel on a machine that supports 137 * recoverable errors because they have too much memory to boot 32-bit. 138 */ 139 #endif 140 141 #endif /* _ASM_X86_SET_MEMORY_H */ 142