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 * Reserved RAM used by the kernel itself if
33 * CONFIG_INTEL_TXT=y is enabled, memory of this type
34 * will be included in the S3 integrity calculation
35 * and so should not include any memory that the BIOS
36 * might alter over the S3 transition:
37 */
38 E820_TYPE_RESERVED_KERN = 128,
39};
40
41/*
42 * A single E820 map entry, describing a memory range of [addr...addr+size-1],
43 * of 'type' memory type:
44 *
45 * (We pack it because there can be thousands of them on large systems.)
46 */
47struct e820_entry {
48 u64 addr;
49 u64 size;
50 enum e820_type type;
51} __attribute__((packed));
52
53/*
54 * The legacy E820 BIOS limits us to 128 (E820_MAX_ENTRIES_ZEROPAGE) nodes
55 * due to the constrained space in the zeropage.
56 *
57 * On large systems we can easily have thousands of nodes with RAM,
58 * which cannot be fit into so few entries - so we have a mechanism
59 * to extend the e820 table size at build-time, via the E820_MAX_ENTRIES
60 * define below.
61 *
62 * ( Those extra entries are enumerated via the EFI memory map, not
63 * via the legacy zeropage mechanism. )
64 *
65 * Size our internal memory map tables to have room for these additional
66 * entries, based on a heuristic calculation: up to three entries per
67 * NUMA node, plus E820_MAX_ENTRIES_ZEROPAGE for some extra space.
68 *
69 * This allows for bootstrap/firmware quirks such as possible duplicate
70 * E820 entries that might need room in the same arrays, prior to the
71 * call to e820__update_table() to remove duplicates. The allowance
72 * of three memory map entries per node is "enough" entries for
73 * the initial hardware platform motivating this mechanism to make
74 * use of additional EFI map entries. Future platforms may want
75 * to allow more than three entries per node or otherwise refine
76 * this size.
77 */
78
79#include <linux/numa.h>
80
81#define E820_MAX_ENTRIES (E820_MAX_ENTRIES_ZEROPAGE + 3*MAX_NUMNODES)
82
83/*
84 * The whole array of E820 entries:
85 */
86struct e820_table {
87 __u32 nr_entries;
88 struct e820_entry entries[E820_MAX_ENTRIES];
89};
90
91/*
92 * Various well-known legacy memory ranges in physical memory:
93 */
94#define ISA_START_ADDRESS 0x000a0000
95#define ISA_END_ADDRESS 0x00100000
96
97#define BIOS_BEGIN 0x000a0000
98#define BIOS_END 0x00100000
99
100#define HIGH_MEMORY 0x00100000
101
102#define BIOS_ROM_BASE 0xffe00000
103#define BIOS_ROM_END 0xffffffff
104
105#endif /* _ASM_E820_TYPES_H */
106