xref: /openbmc/linux/arch/x86/include/asm/highmem.h (revision 4e140f59)
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/tlbflush.h>
27 #include <asm/paravirt.h>
28 #include <asm/fixmap.h>
29 #include <asm/pgtable_areas.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 #define flush_cache_kmaps()	do { } while (0)
62 
63 #define	arch_kmap_local_post_map(vaddr, pteval)		\
64 	arch_flush_lazy_mmu_mode()
65 
66 #define	arch_kmap_local_post_unmap(vaddr)		\
67 	do {						\
68 		flush_tlb_one_kernel((vaddr));		\
69 		arch_flush_lazy_mmu_mode();		\
70 	} while (0)
71 
72 extern void add_highpages_with_active_regions(int nid, unsigned long start_pfn,
73 					unsigned long end_pfn);
74 
75 #endif /* __KERNEL__ */
76 
77 #endif /* _ASM_X86_HIGHMEM_H */
78