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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_SET_MEMORY_H
#define _ASM_X86_SET_MEMORY_H
#include <asm/page.h>
#include <asm-generic/set_memory.h>
* The set_memory_* API can be used to change various attributes of a virtual
* address range. The attributes include:
* Cacheability : UnCached, WriteCombining, WriteThrough, WriteBack
* Executability : eXecutable, NoteXecutable
* Read/Write : ReadOnly, ReadWrite
* Presence : NotPresent
* Encryption : Encrypted, Decrypted
* Within a category, the attributes are mutually exclusive.
* The implementation of this API will take care of various aspects that
* are associated with changing such attributes, such as:
* - Flushing TLBs
* - Flushing CPU caches
* - Making sure aliases of the memory behind the mapping don't violate
* coherency rules as defined by the CPU in the system.
* What this API does not do:
* - Provide exclusion between various callers - including callers that
* operation on other mappings of the same physical page
* - Restore default attributes when a page is freed
* - Guarantee that mappings other than the requested one are
* in any state, other than that these do not violate rules for
* the CPU you have. Do not depend on any effects on other mappings,
* CPUs other than the one you have may have more relaxed rules.
* The caller is required to take care of these.
int __set_memory_prot(unsigned long addr, int numpages, pgprot_t prot);
int _set_memory_uc(unsigned long addr, int numpages);
int _set_memory_wc(unsigned long addr, int numpages);
int _set_memory_wt(unsigned long addr, int numpages);
int _set_memory_wb(unsigned long addr, int numpages);
int set_memory_uc(unsigned long addr, int numpages);
int set_memory_wc(unsigned long addr, int numpages);
int set_memory_wb(unsigned long addr, int numpages);
int set_memory_np(unsigned long addr, int numpages);
int set_memory_4k(unsigned long addr, int numpages);
int set_memory_encrypted(unsigned long addr, int numpages);
int set_memory_decrypted(unsigned long addr, int numpages);
int set_memory_np_noalias(unsigned long addr, int numpages);
int set_memory_nonglobal(unsigned long addr, int numpages);
int set_memory_global(unsigned long addr, int numpages);
int set_pages_array_uc(struct page **pages, int addrinarray);
int set_pages_array_wc(struct page **pages, int addrinarray);
int set_pages_array_wt(struct page **pages, int addrinarray);
int set_pages_array_wb(struct page **pages, int addrinarray);
* For legacy compatibility with the old APIs, a few functions
* are provided that work on a "struct page".
* These functions operate ONLY on the 1:1 kernel mapping of the
* memory that the struct page represents, and internally just
* call the set_memory_* function. See the description of the
* set_memory_* function for more details on conventions.
* These APIs should be considered *deprecated* and are likely going to
* be removed in the future.
* The reason for this is the implicit operation on the 1:1 mapping only,
* making this not a generally useful API.
* Specifically, many users of the old APIs had a virtual address,
* called virt_to_page() or vmalloc_to_page() on that address to
* get a struct page* that the old API required.
* To convert these cases, use set_memory_*() on the original
* virtual address, do not use these functions.
int set_pages_uc(struct page *page, int numpages);
int set_pages_wb(struct page *page, int numpages);
int set_pages_ro(struct page *page, int numpages);
int set_pages_rw(struct page *page, int numpages);
int set_direct_map_invalid_noflush(struct page *page);
int set_direct_map_default_noflush(struct page *page);
bool kernel_page_present(struct page *page);
extern int kernel_set_to_readonly;
#ifdef CONFIG_X86_64
* Prevent speculative access to the page by either unmapping
* it (if we do not require access to any part of the page) or
* marking it uncacheable (if we want to try to retrieve data
* from non-poisoned lines in the page).
static inline int set_mce_nospec(unsigned long pfn, bool unmap)
unsigned long decoy_addr;
int rc;
* We would like to just call:
* set_memory_XX((unsigned long)pfn_to_kaddr(pfn), 1);
* but doing that would radically increase the odds of a
* speculative access to the poison page because we'd have
* the virtual address of the kernel 1:1 mapping sitting
* around in registers.
* Instead we get tricky. We create a non-canonical address
* that looks just like the one we want, but has bit 63 flipped.
* This relies on set_memory_XX() properly sanitizing any __pa()
* results with __PHYSICAL_MASK or PTE_PFN_MASK.
decoy_addr = (pfn << PAGE_SHIFT) + (PAGE_OFFSET ^ BIT(63));
if (unmap)
rc = set_memory_np(decoy_addr, 1);
rc = set_memory_uc(decoy_addr, 1);
if (rc)
pr_warn("Could not invalidate pfn=0x%lx from 1:1 map\n", pfn);
return rc;
#define set_mce_nospec set_mce_nospec
/* Restore full speculative operation to the pfn. */
static inline int clear_mce_nospec(unsigned long pfn)
return set_memory_wb((unsigned long) pfn_to_kaddr(pfn), 1);
#define clear_mce_nospec clear_mce_nospec
* Few people would run a 32-bit kernel on a machine that supports
* recoverable errors because they have too much memory to boot 32-bit.
#endif /* _ASM_X86_SET_MEMORY_H */