55 lines
1.2 KiB
C
55 lines
1.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
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#ifndef _LINUX_SECRETMEM_H
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#define _LINUX_SECRETMEM_H
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#ifdef CONFIG_SECRETMEM
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extern const struct address_space_operations secretmem_aops;
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static inline bool page_is_secretmem(struct page *page)
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{
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struct address_space *mapping;
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/*
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* Using page_mapping() is quite slow because of the actual call
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* instruction and repeated compound_head(page) inside the
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* page_mapping() function.
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* We know that secretmem pages are not compound and LRU so we can
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* save a couple of cycles here.
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*/
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if (PageCompound(page) || !PageLRU(page))
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return false;
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mapping = (struct address_space *)
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((unsigned long)page->mapping & ~PAGE_MAPPING_FLAGS);
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if (!mapping || mapping != page->mapping)
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return false;
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return mapping->a_ops == &secretmem_aops;
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}
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bool vma_is_secretmem(struct vm_area_struct *vma);
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bool secretmem_active(void);
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#else
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static inline bool vma_is_secretmem(struct vm_area_struct *vma)
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{
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return false;
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}
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static inline bool page_is_secretmem(struct page *page)
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{
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return false;
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}
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static inline bool secretmem_active(void)
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{
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return false;
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}
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#endif /* CONFIG_SECRETMEM */
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#endif /* _LINUX_SECRETMEM_H */
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