1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * highmem.h: virtual kernel memory mappings for high memory 4 * 5 * Used in CONFIG_HIGHMEM systems for memory pages which 6 * are not addressable by direct kernel virtual addresses. 7 * 8 * Copyright (C) 1999 Gerhard Wichert, Siemens AG 9 * Gerhard.Wichert@pdb.siemens.de 10 * 11 * 12 * Redesigned the x86 32-bit VM architecture to deal with 13 * up to 16 Terabyte physical memory. With current x86 CPUs 14 * we now support up to 64 Gigabytes physical RAM. 15 * 16 * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com> 17 */ 18 19 #ifndef _ASM_X86_HIGHMEM_H 20 #define _ASM_X86_HIGHMEM_H 21 22 #ifdef __KERNEL__ 23 24 #include <linux/interrupt.h> 25 #include <linux/threads.h> 26 #include <asm/kmap_types.h> 27 #include <asm/tlbflush.h> 28 #include <asm/paravirt.h> 29 #include <asm/fixmap.h> 30 31 /* declarations for highmem.c */ 32 extern unsigned long highstart_pfn, highend_pfn; 33 34 /* 35 * Right now we initialize only a single pte table. It can be extended 36 * easily, subsequent pte tables have to be allocated in one physical 37 * chunk of RAM. 38 */ 39 /* 40 * Ordering is: 41 * 42 * high memory on: high_memory off: 43 * FIXADDR_TOP FIXADDR_TOP 44 * fixed addresses fixed addresses 45 * FIXADDR_START FIXADDR_START 46 * temp fixed addresses/persistent kmap area VMALLOC_END 47 * PKMAP_BASE temp fixed addresses/vmalloc area 48 * VMALLOC_END VMALLOC_START 49 * vmalloc area high_memory 50 * VMALLOC_START 51 * high_memory 52 * 53 * The temp fixed area is only used during boot for early_ioremap(), and 54 * it is unused when the ioremap() is functional. vmalloc/pkmap area become 55 * available after early boot so the temp fixed area is available for re-use. 56 */ 57 #define LAST_PKMAP_MASK (LAST_PKMAP-1) 58 #define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT) 59 #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) 60 61 extern void *kmap_high(struct page *page); 62 extern void kunmap_high(struct page *page); 63 64 void *kmap(struct page *page); 65 void kunmap(struct page *page); 66 67 void *kmap_atomic_prot(struct page *page, pgprot_t prot); 68 void *kmap_atomic(struct page *page); 69 void __kunmap_atomic(void *kvaddr); 70 void *kmap_atomic_pfn(unsigned long pfn); 71 void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot); 72 73 #define flush_cache_kmaps() do { } while (0) 74 75 extern void add_highpages_with_active_regions(int nid, unsigned long start_pfn, 76 unsigned long end_pfn); 77 78 #endif /* __KERNEL__ */ 79 80 #endif /* _ASM_X86_HIGHMEM_H */ 81