xref: /linux/arch/arm64/include/asm/fixmap.h (revision a36e9f5cfe9eb3a1dce8769c7058251c42705357)
1 /*
2  * fixmap.h: compile-time virtual memory allocation
3  *
4  * This file is subject to the terms and conditions of the GNU General Public
5  * License.  See the file "COPYING" in the main directory of this archive
6  * for more details.
7  *
8  * Copyright (C) 1998 Ingo Molnar
9  * Copyright (C) 2013 Mark Salter <msalter@redhat.com>
10  *
11  * Adapted from arch/x86 version.
12  *
13  */
14 
15 #ifndef _ASM_ARM64_FIXMAP_H
16 #define _ASM_ARM64_FIXMAP_H
17 
18 #ifndef __ASSEMBLY__
19 #include <linux/kernel.h>
20 #include <linux/math.h>
21 #include <linux/sizes.h>
22 #include <asm/boot.h>
23 #include <asm/page.h>
24 #include <asm/pgtable-prot.h>
25 
26 /*
27  * Here we define all the compile-time 'special' virtual
28  * addresses. The point is to have a constant address at
29  * compile time, but to set the physical address only
30  * in the boot process.
31  *
32  * Each enum increment in these 'compile-time allocated'
33  * memory buffers is page-sized. Use set_fixmap(idx,phys)
34  * to associate physical memory with a fixmap index.
35  */
36 enum fixed_addresses {
37 	FIX_HOLE,
38 
39 	/*
40 	 * Reserve a virtual window for the FDT that is a page bigger than the
41 	 * maximum supported size. The additional space ensures that any FDT
42 	 * that does not exceed MAX_FDT_SIZE can be mapped regardless of
43 	 * whether it crosses any page boundary.
44 	 */
45 	FIX_FDT_END,
46 	FIX_FDT = FIX_FDT_END + DIV_ROUND_UP(MAX_FDT_SIZE, PAGE_SIZE) + 1,
47 
48 	FIX_EARLYCON_MEM_BASE,
49 	FIX_TEXT_POKE0,
50 
51 #ifdef CONFIG_ACPI_APEI_GHES
52 	/* Used for GHES mapping from assorted contexts */
53 	FIX_APEI_GHES_IRQ,
54 	FIX_APEI_GHES_SEA,
55 #ifdef CONFIG_ARM_SDE_INTERFACE
56 	FIX_APEI_GHES_SDEI_NORMAL,
57 	FIX_APEI_GHES_SDEI_CRITICAL,
58 #endif
59 #endif /* CONFIG_ACPI_APEI_GHES */
60 
61 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
62 #ifdef CONFIG_RELOCATABLE
63 	FIX_ENTRY_TRAMP_TEXT4,	/* one extra slot for the data page */
64 #endif
65 	FIX_ENTRY_TRAMP_TEXT3,
66 	FIX_ENTRY_TRAMP_TEXT2,
67 	FIX_ENTRY_TRAMP_TEXT1,
68 #define TRAMP_VALIAS		(__fix_to_virt(FIX_ENTRY_TRAMP_TEXT1))
69 #endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */
70 	__end_of_permanent_fixed_addresses,
71 
72 	/*
73 	 * Temporary boot-time mappings, used by early_ioremap(),
74 	 * before ioremap() is functional.
75 	 */
76 #define NR_FIX_BTMAPS		(SZ_256K / PAGE_SIZE)
77 #define FIX_BTMAPS_SLOTS	7
78 #define TOTAL_FIX_BTMAPS	(NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
79 
80 	FIX_BTMAP_END = __end_of_permanent_fixed_addresses,
81 	FIX_BTMAP_BEGIN = FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1,
82 
83 	/*
84 	 * Used for kernel page table creation, so unmapped memory may be used
85 	 * for tables.
86 	 */
87 	FIX_PTE,
88 	FIX_PMD,
89 	FIX_PUD,
90 	FIX_P4D,
91 	FIX_PGD,
92 
93 	__end_of_fixed_addresses
94 };
95 
96 #define FIXADDR_SIZE		(__end_of_permanent_fixed_addresses << PAGE_SHIFT)
97 #define FIXADDR_START		(FIXADDR_TOP - FIXADDR_SIZE)
98 #define FIXADDR_TOT_SIZE	(__end_of_fixed_addresses << PAGE_SHIFT)
99 #define FIXADDR_TOT_START	(FIXADDR_TOP - FIXADDR_TOT_SIZE)
100 
101 #define FIXMAP_PAGE_IO     __pgprot(PROT_DEVICE_nGnRE)
102 
103 void __init early_fixmap_init(void);
104 
105 #define __early_set_fixmap __set_fixmap
106 
107 #define __late_set_fixmap __set_fixmap
108 #define __late_clear_fixmap(idx) __set_fixmap((idx), 0, FIXMAP_PAGE_CLEAR)
109 
110 extern void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot);
111 
112 #include <asm-generic/fixmap.h>
113 
114 #endif /* !__ASSEMBLY__ */
115 #endif /* _ASM_ARM64_FIXMAP_H */
116