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![Matthew Wilcox (Oracle)](/assets/img/avatar_default.png)
If you are copying to an address in the kmap region, you may not copy across a page boundary, no matter what the size of the underlying allocation. You can't kmap() a slab page because slab pages always come from low memory. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220110231530.665970-2-willy@infradead.org
275 lines
6 KiB
C
275 lines
6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_HIGHMEM_INTERNAL_H
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#define _LINUX_HIGHMEM_INTERNAL_H
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/*
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* Outside of CONFIG_HIGHMEM to support X86 32bit iomap_atomic() cruft.
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*/
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#ifdef CONFIG_KMAP_LOCAL
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void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot);
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void *__kmap_local_page_prot(struct page *page, pgprot_t prot);
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void kunmap_local_indexed(void *vaddr);
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void kmap_local_fork(struct task_struct *tsk);
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void __kmap_local_sched_out(void);
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void __kmap_local_sched_in(void);
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static inline void kmap_assert_nomap(void)
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{
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DEBUG_LOCKS_WARN_ON(current->kmap_ctrl.idx);
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}
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#else
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static inline void kmap_local_fork(struct task_struct *tsk) { }
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static inline void kmap_assert_nomap(void) { }
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#endif
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#ifdef CONFIG_HIGHMEM
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#include <asm/highmem.h>
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#ifndef ARCH_HAS_KMAP_FLUSH_TLB
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static inline void kmap_flush_tlb(unsigned long addr) { }
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#endif
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#ifndef kmap_prot
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#define kmap_prot PAGE_KERNEL
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#endif
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void *kmap_high(struct page *page);
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void kunmap_high(struct page *page);
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void __kmap_flush_unused(void);
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struct page *__kmap_to_page(void *addr);
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static inline void *kmap(struct page *page)
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{
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void *addr;
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might_sleep();
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if (!PageHighMem(page))
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addr = page_address(page);
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else
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addr = kmap_high(page);
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kmap_flush_tlb((unsigned long)addr);
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return addr;
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}
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static inline void kunmap(struct page *page)
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{
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might_sleep();
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if (!PageHighMem(page))
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return;
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kunmap_high(page);
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}
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static inline struct page *kmap_to_page(void *addr)
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{
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return __kmap_to_page(addr);
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}
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static inline void kmap_flush_unused(void)
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{
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__kmap_flush_unused();
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}
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static inline void *kmap_local_page(struct page *page)
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{
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return __kmap_local_page_prot(page, kmap_prot);
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}
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static inline void *kmap_local_folio(struct folio *folio, size_t offset)
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{
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struct page *page = folio_page(folio, offset / PAGE_SIZE);
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return __kmap_local_page_prot(page, kmap_prot) + offset % PAGE_SIZE;
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}
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static inline void *kmap_local_page_prot(struct page *page, pgprot_t prot)
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{
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return __kmap_local_page_prot(page, prot);
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}
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static inline void *kmap_local_pfn(unsigned long pfn)
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{
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return __kmap_local_pfn_prot(pfn, kmap_prot);
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}
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static inline void __kunmap_local(void *vaddr)
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{
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kunmap_local_indexed(vaddr);
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}
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static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
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{
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if (IS_ENABLED(CONFIG_PREEMPT_RT))
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migrate_disable();
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else
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preempt_disable();
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pagefault_disable();
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return __kmap_local_page_prot(page, prot);
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}
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static inline void *kmap_atomic(struct page *page)
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{
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return kmap_atomic_prot(page, kmap_prot);
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}
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static inline void *kmap_atomic_pfn(unsigned long pfn)
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{
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if (IS_ENABLED(CONFIG_PREEMPT_RT))
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migrate_disable();
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else
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preempt_disable();
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pagefault_disable();
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return __kmap_local_pfn_prot(pfn, kmap_prot);
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}
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static inline void __kunmap_atomic(void *addr)
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{
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kunmap_local_indexed(addr);
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pagefault_enable();
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if (IS_ENABLED(CONFIG_PREEMPT_RT))
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migrate_enable();
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else
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preempt_enable();
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}
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unsigned int __nr_free_highpages(void);
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extern atomic_long_t _totalhigh_pages;
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static inline unsigned int nr_free_highpages(void)
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{
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return __nr_free_highpages();
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}
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static inline unsigned long totalhigh_pages(void)
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{
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return (unsigned long)atomic_long_read(&_totalhigh_pages);
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}
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static inline void totalhigh_pages_add(long count)
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{
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atomic_long_add(count, &_totalhigh_pages);
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}
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static inline bool is_kmap_addr(const void *x)
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{
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unsigned long addr = (unsigned long)x;
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return addr >= PKMAP_ADDR(0) && addr < PKMAP_ADDR(LAST_PKMAP);
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}
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#else /* CONFIG_HIGHMEM */
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static inline struct page *kmap_to_page(void *addr)
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{
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return virt_to_page(addr);
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}
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static inline void *kmap(struct page *page)
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{
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might_sleep();
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return page_address(page);
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}
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static inline void kunmap_high(struct page *page) { }
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static inline void kmap_flush_unused(void) { }
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static inline void kunmap(struct page *page)
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{
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#ifdef ARCH_HAS_FLUSH_ON_KUNMAP
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kunmap_flush_on_unmap(page_address(page));
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#endif
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}
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static inline void *kmap_local_page(struct page *page)
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{
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return page_address(page);
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}
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static inline void *kmap_local_folio(struct folio *folio, size_t offset)
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{
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return page_address(&folio->page) + offset;
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}
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static inline void *kmap_local_page_prot(struct page *page, pgprot_t prot)
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{
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return kmap_local_page(page);
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}
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static inline void *kmap_local_pfn(unsigned long pfn)
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{
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return kmap_local_page(pfn_to_page(pfn));
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}
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static inline void __kunmap_local(void *addr)
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{
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#ifdef ARCH_HAS_FLUSH_ON_KUNMAP
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kunmap_flush_on_unmap(addr);
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#endif
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}
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static inline void *kmap_atomic(struct page *page)
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{
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if (IS_ENABLED(CONFIG_PREEMPT_RT))
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migrate_disable();
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else
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preempt_disable();
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pagefault_disable();
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return page_address(page);
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}
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static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
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{
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return kmap_atomic(page);
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}
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static inline void *kmap_atomic_pfn(unsigned long pfn)
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{
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return kmap_atomic(pfn_to_page(pfn));
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}
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static inline void __kunmap_atomic(void *addr)
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{
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#ifdef ARCH_HAS_FLUSH_ON_KUNMAP
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kunmap_flush_on_unmap(addr);
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#endif
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pagefault_enable();
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if (IS_ENABLED(CONFIG_PREEMPT_RT))
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migrate_enable();
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else
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preempt_enable();
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}
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static inline unsigned int nr_free_highpages(void) { return 0; }
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static inline unsigned long totalhigh_pages(void) { return 0UL; }
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static inline bool is_kmap_addr(const void *x)
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{
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return false;
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}
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#endif /* CONFIG_HIGHMEM */
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/*
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* Prevent people trying to call kunmap_atomic() as if it were kunmap()
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* kunmap_atomic() should get the return value of kmap_atomic, not the page.
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*/
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#define kunmap_atomic(__addr) \
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do { \
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BUILD_BUG_ON(__same_type((__addr), struct page *)); \
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__kunmap_atomic(__addr); \
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} while (0)
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/**
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* kunmap_local - Unmap a page mapped via kmap_local_page().
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* @__addr: An address within the page mapped
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*
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* @__addr can be any address within the mapped page. Commonly it is the
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* address return from kmap_local_page(), but it can also include offsets.
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*
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* Unmapping should be done in the reverse order of the mapping. See
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* kmap_local_page() for details.
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*/
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#define kunmap_local(__addr) \
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do { \
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BUILD_BUG_ON(__same_type((__addr), struct page *)); \
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__kunmap_local(__addr); \
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} while (0)
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#endif
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