xref: /openbmc/linux/arch/x86/include/uapi/asm/e820.h (revision 6f52b16c)
1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2 #ifndef _UAPI_ASM_X86_E820_H
3 #define _UAPI_ASM_X86_E820_H
4 #define E820MAP	0x2d0		/* our map */
5 #define E820MAX	128		/* number of entries in E820MAP */
6 
7 /*
8  * Legacy E820 BIOS limits us to 128 (E820MAX) nodes due to the
9  * constrained space in the zeropage.  If we have more nodes than
10  * that, and if we've booted off EFI firmware, then the EFI tables
11  * passed us from the EFI firmware can list more nodes.  Size our
12  * internal memory map tables to have room for these additional
13  * nodes, based on up to three entries per node for which the
14  * kernel was built: MAX_NUMNODES == (1 << CONFIG_NODES_SHIFT),
15  * plus E820MAX, allowing space for the possible duplicate E820
16  * entries that might need room in the same arrays, prior to the
17  * call to sanitize_e820_map() to remove duplicates.  The allowance
18  * of three memory map entries per node is "enough" entries for
19  * the initial hardware platform motivating this mechanism to make
20  * use of additional EFI map entries.  Future platforms may want
21  * to allow more than three entries per node or otherwise refine
22  * this size.
23  */
24 
25 #ifndef __KERNEL__
26 #define E820_X_MAX E820MAX
27 #endif
28 
29 #define E820NR	0x1e8		/* # entries in E820MAP */
30 
31 #define E820_RAM	1
32 #define E820_RESERVED	2
33 #define E820_ACPI	3
34 #define E820_NVS	4
35 #define E820_UNUSABLE	5
36 #define E820_PMEM	7
37 
38 /*
39  * This is a non-standardized way to represent ADR or NVDIMM regions that
40  * persist over a reboot.  The kernel will ignore their special capabilities
41  * unless the CONFIG_X86_PMEM_LEGACY option is set.
42  *
43  * ( Note that older platforms also used 6 for the same type of memory,
44  *   but newer versions switched to 12 as 6 was assigned differently.  Some
45  *   time they will learn... )
46  */
47 #define E820_PRAM	12
48 
49 /*
50  * reserved RAM used by kernel itself
51  * if CONFIG_INTEL_TXT is enabled, memory of this type will be
52  * included in the S3 integrity calculation and so should not include
53  * any memory that BIOS might alter over the S3 transition
54  */
55 #define E820_RESERVED_KERN        128
56 
57 #ifndef __ASSEMBLY__
58 #include <linux/types.h>
59 struct e820entry {
60 	__u64 addr;	/* start of memory segment */
61 	__u64 size;	/* size of memory segment */
62 	__u32 type;	/* type of memory segment */
63 } __attribute__((packed));
64 
65 struct e820map {
66 	__u32 nr_map;
67 	struct e820entry map[E820_X_MAX];
68 };
69 
70 #define ISA_START_ADDRESS	0xa0000
71 #define ISA_END_ADDRESS		0x100000
72 
73 #define BIOS_BEGIN		0x000a0000
74 #define BIOS_END		0x00100000
75 
76 #define BIOS_ROM_BASE		0xffe00000
77 #define BIOS_ROM_END		0xffffffff
78 
79 #endif /* __ASSEMBLY__ */
80 
81 
82 #endif /* _UAPI_ASM_X86_E820_H */
83