types.h

  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 */