1b2441318SGreg Kroah-Hartman /* SPDX-License-Identifier: GPL-2.0 */
22f2f371fSMichal Simek /*
32f2f371fSMichal Simek  * highmem.h: virtual kernel memory mappings for high memory
42f2f371fSMichal Simek  *
52f2f371fSMichal Simek  * Used in CONFIG_HIGHMEM systems for memory pages which
62f2f371fSMichal Simek  * are not addressable by direct kernel virtual addresses.
72f2f371fSMichal Simek  *
82f2f371fSMichal Simek  * Copyright (C) 1999 Gerhard Wichert, Siemens AG
92f2f371fSMichal Simek  *		      Gerhard.Wichert@pdb.siemens.de
102f2f371fSMichal Simek  *
112f2f371fSMichal Simek  *
122f2f371fSMichal Simek  * Redesigned the x86 32-bit VM architecture to deal with
132f2f371fSMichal Simek  * up to 16 Terabyte physical memory. With current x86 CPUs
142f2f371fSMichal Simek  * we now support up to 64 Gigabytes physical RAM.
152f2f371fSMichal Simek  *
162f2f371fSMichal Simek  * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
172f2f371fSMichal Simek  */
182f2f371fSMichal Simek #ifndef _ASM_HIGHMEM_H
192f2f371fSMichal Simek #define _ASM_HIGHMEM_H
202f2f371fSMichal Simek 
212f2f371fSMichal Simek #ifdef __KERNEL__
222f2f371fSMichal Simek 
232f2f371fSMichal Simek #include <linux/init.h>
242f2f371fSMichal Simek #include <linux/interrupt.h>
252f2f371fSMichal Simek #include <linux/uaccess.h>
262f2f371fSMichal Simek #include <asm/fixmap.h>
272f2f371fSMichal Simek 
282f2f371fSMichal Simek extern pte_t *kmap_pte;
292f2f371fSMichal Simek extern pgprot_t kmap_prot;
302f2f371fSMichal Simek extern pte_t *pkmap_page_table;
312f2f371fSMichal Simek 
322f2f371fSMichal Simek /*
332f2f371fSMichal Simek  * Right now we initialize only a single pte table. It can be extended
342f2f371fSMichal Simek  * easily, subsequent pte tables have to be allocated in one physical
352f2f371fSMichal Simek  * chunk of RAM.
362f2f371fSMichal Simek  */
372f2f371fSMichal Simek /*
382f2f371fSMichal Simek  * We use one full pte table with 4K pages. And with 16K/64K/256K pages pte
392f2f371fSMichal Simek  * table covers enough memory (32MB/512MB/2GB resp.), so that both FIXMAP
402f2f371fSMichal Simek  * and PKMAP can be placed in a single pte table. We use 512 pages for PKMAP
412f2f371fSMichal Simek  * in case of 16K/64K/256K page sizes.
422f2f371fSMichal Simek  */
432f2f371fSMichal Simek 
442f2f371fSMichal Simek #define PKMAP_ORDER	PTE_SHIFT
452f2f371fSMichal Simek #define LAST_PKMAP	(1 << PKMAP_ORDER)
462f2f371fSMichal Simek 
472f2f371fSMichal Simek #define PKMAP_BASE	((FIXADDR_START - PAGE_SIZE * (LAST_PKMAP + 1)) \
482f2f371fSMichal Simek 								& PMD_MASK)
492f2f371fSMichal Simek 
502f2f371fSMichal Simek #define LAST_PKMAP_MASK	(LAST_PKMAP - 1)
512f2f371fSMichal Simek #define PKMAP_NR(virt)  ((virt - PKMAP_BASE) >> PAGE_SHIFT)
522f2f371fSMichal Simek #define PKMAP_ADDR(nr)  (PKMAP_BASE + ((nr) << PAGE_SHIFT))
532f2f371fSMichal Simek 
542f2f371fSMichal Simek extern void *kmap_high(struct page *page);
552f2f371fSMichal Simek extern void kunmap_high(struct page *page);
562f2f371fSMichal Simek extern void *kmap_atomic_prot(struct page *page, pgprot_t prot);
572f2f371fSMichal Simek extern void __kunmap_atomic(void *kvaddr);
582f2f371fSMichal Simek 
592f2f371fSMichal Simek static inline void *kmap(struct page *page)
602f2f371fSMichal Simek {
612f2f371fSMichal Simek 	might_sleep();
622f2f371fSMichal Simek 	if (!PageHighMem(page))
632f2f371fSMichal Simek 		return page_address(page);
642f2f371fSMichal Simek 	return kmap_high(page);
652f2f371fSMichal Simek }
662f2f371fSMichal Simek 
672f2f371fSMichal Simek static inline void kunmap(struct page *page)
682f2f371fSMichal Simek {
692f2f371fSMichal Simek 	BUG_ON(in_interrupt());
702f2f371fSMichal Simek 	if (!PageHighMem(page))
712f2f371fSMichal Simek 		return;
722f2f371fSMichal Simek 	kunmap_high(page);
732f2f371fSMichal Simek }
742f2f371fSMichal Simek 
75ffed2b4fSMichal Simek static inline void *kmap_atomic(struct page *page)
762f2f371fSMichal Simek {
772f2f371fSMichal Simek 	return kmap_atomic_prot(page, kmap_prot);
782f2f371fSMichal Simek }
792f2f371fSMichal Simek 
802f2f371fSMichal Simek #define flush_cache_kmaps()	{ flush_icache(); flush_dcache(); }
812f2f371fSMichal Simek 
822f2f371fSMichal Simek #endif /* __KERNEL__ */
832f2f371fSMichal Simek 
842f2f371fSMichal Simek #endif /* _ASM_HIGHMEM_H */
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