1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_E820_TYPES_H
3#define _ASM_E820_TYPES_H
4
5#include <uapi/asm/bootparam.h>
6
7/*
8 * These are the E820 types known to the kernel:
9 */
10enum e820_type {
11 E820_TYPE_RAM = 1,
12 E820_TYPE_RESERVED = 2,
13 E820_TYPE_ACPI = 3,
14 E820_TYPE_NVS = 4,
15 E820_TYPE_UNUSABLE = 5,
16 E820_TYPE_PMEM = 7,
17
18 /*
19 * This is a non-standardized way to represent ADR or
20 * NVDIMM regions that persist over a reboot.
21 *
22 * The kernel will ignore their special capabilities
23 * unless the CONFIG_X86_PMEM_LEGACY=y option is set.
24 *
25 * ( Note that older platforms also used 6 for the same
26 * type of memory, but newer versions switched to 12 as
27 * 6 was assigned differently. Some time they will learn... )
28 */
29 E820_TYPE_PRAM = 12,
30
31 /*
32 * Special-purpose memory is indicated to the system via the
33 * EFI_MEMORY_SP attribute. Define an e820 translation of this
34 * memory type for the purpose of reserving this range and
35 * marking it with the IORES_DESC_SOFT_RESERVED designation.
36 */
37 E820_TYPE_SOFT_RESERVED = 0xefffffff,
38};
39
40/*
41 * A single E820 map entry, describing a memory range of [addr...addr+size-1],
42 * of 'type' memory type:
43 *
44 * (We pack it because there can be thousands of them on large systems.)
45 */
46struct e820_entry {
47 u64 addr;
48 u64 size;
49 enum e820_type type;
50} __attribute__((packed));
51
52/*
53 * The legacy E820 BIOS limits us to 128 (E820_MAX_ENTRIES_ZEROPAGE) nodes
54 * due to the constrained space in the zeropage.
55 *
56 * On large systems we can easily have thousands of nodes with RAM,
57 * which cannot be fit into so few entries - so we have a mechanism
58 * to extend the e820 table size at build-time, via the E820_MAX_ENTRIES
59 * define below.
60 *
61 * ( Those extra entries are enumerated via the EFI memory map, not
62 * via the legacy zeropage mechanism. )
63 *
64 * Size our internal memory map tables to have room for these additional
65 * entries, based on a heuristic calculation: up to three entries per
66 * NUMA node, plus E820_MAX_ENTRIES_ZEROPAGE for some extra space.
67 *
68 * This allows for bootstrap/firmware quirks such as possible duplicate
69 * E820 entries that might need room in the same arrays, prior to the
70 * call to e820__update_table() to remove duplicates. The allowance
71 * of three memory map entries per node is "enough" entries for
72 * the initial hardware platform motivating this mechanism to make
73 * use of additional EFI map entries. Future platforms may want
74 * to allow more than three entries per node or otherwise refine
75 * this size.
76 */
77
78#include <linux/numa.h>
79
80#define E820_MAX_ENTRIES (E820_MAX_ENTRIES_ZEROPAGE + 3*MAX_NUMNODES)
81
82/*
83 * The whole array of E820 entries:
84 */
85struct e820_table {
86 __u32 nr_entries;
87 struct e820_entry entries[E820_MAX_ENTRIES];
88};
89
90/*
91 * Various well-known legacy memory ranges in physical memory:
92 */
93#define ISA_START_ADDRESS 0x000a0000
94#define ISA_END_ADDRESS 0x00100000
95
96#define BIOS_BEGIN 0x000a0000
97#define BIOS_END 0x00100000
98
99#define HIGH_MEMORY 0x00100000
100
101#define BIOS_ROM_BASE 0xffe00000
102#define BIOS_ROM_END 0xffffffff
103
104#endif /* _ASM_E820_TYPES_H */
105

source code of linux/arch/x86/include/asm/e820/types.h