arch/x86/include/asm/set_memory.h

   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_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 */