1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_X86_BOOT_H
3#define _ASM_X86_BOOT_H
4
5
6#include <asm/pgtable_types.h>
7#include <uapi/asm/boot.h>
8
9/* Physical address where kernel should be loaded. */
10#define LOAD_PHYSICAL_ADDR ((CONFIG_PHYSICAL_START \
11 + (CONFIG_PHYSICAL_ALIGN - 1)) \
12 & ~(CONFIG_PHYSICAL_ALIGN - 1))
13
14/* Minimum kernel alignment, as a power of two */
15#ifdef CONFIG_X86_64
16# define MIN_KERNEL_ALIGN_LG2 PMD_SHIFT
17#else
18# define MIN_KERNEL_ALIGN_LG2 (PAGE_SHIFT + THREAD_SIZE_ORDER)
19#endif
20#define MIN_KERNEL_ALIGN (_AC(1, UL) << MIN_KERNEL_ALIGN_LG2)
21
22#if (CONFIG_PHYSICAL_ALIGN & (CONFIG_PHYSICAL_ALIGN-1)) || \
23 (CONFIG_PHYSICAL_ALIGN < MIN_KERNEL_ALIGN)
24# error "Invalid value for CONFIG_PHYSICAL_ALIGN"
25#endif
26
27#if defined(CONFIG_KERNEL_BZIP2)
28# define BOOT_HEAP_SIZE 0x400000
29#elif defined(CONFIG_KERNEL_ZSTD)
30/*
31 * Zstd needs to allocate the ZSTD_DCtx in order to decompress the kernel.
32 * The ZSTD_DCtx is ~160KB, so set the heap size to 192KB because it is a
33 * round number and to allow some slack.
34 */
35# define BOOT_HEAP_SIZE 0x30000
36#else
37# define BOOT_HEAP_SIZE 0x10000
38#endif
39
40#ifdef CONFIG_X86_64
41# define BOOT_STACK_SIZE 0x4000
42
43/*
44 * Used by decompressor's startup_32() to allocate page tables for identity
45 * mapping of the 4G of RAM in 4-level paging mode:
46 * - 1 level4 table;
47 * - 1 level3 table;
48 * - 4 level2 table that maps everything with 2M pages;
49 *
50 * The additional level5 table needed for 5-level paging is allocated from
51 * trampoline_32bit memory.
52 */
53# define BOOT_INIT_PGT_SIZE (6*4096)
54
55/*
56 * Total number of page tables kernel_add_identity_map() can allocate,
57 * including page tables consumed by startup_32().
58 *
59 * Worst-case scenario:
60 * - 5-level paging needs 1 level5 table;
61 * - KASLR needs to map kernel, boot_params, cmdline and randomized kernel,
62 * assuming all of them cross 256T boundary:
63 * + 4*2 level4 table;
64 * + 4*2 level3 table;
65 * + 4*2 level2 table;
66 * - X86_VERBOSE_BOOTUP needs to map the first 2M (video RAM):
67 * + 1 level4 table;
68 * + 1 level3 table;
69 * + 1 level2 table;
70 * Total: 28 tables
71 *
72 * Add 4 spare table in case decompressor touches anything beyond what is
73 * accounted above. Warn if it happens.
74 */
75# define BOOT_PGT_SIZE_WARN (28*4096)
76# define BOOT_PGT_SIZE (32*4096)
77
78#else /* !CONFIG_X86_64 */
79# define BOOT_STACK_SIZE 0x1000
80#endif
81
82#ifndef __ASSEMBLY__
83extern unsigned int output_len;
84extern const unsigned long kernel_total_size;
85
86unsigned long decompress_kernel(unsigned char *outbuf, unsigned long virt_addr,
87 void (*error)(char *x));
88
89extern struct boot_params *boot_params_ptr;
90#endif
91
92#endif /* _ASM_X86_BOOT_H */
93

source code of linux/arch/x86/include/asm/boot.h