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/* Minimum kernel alignment, as a power of two */
10#ifdef CONFIG_X86_64
11# define MIN_KERNEL_ALIGN_LG2 PMD_SHIFT
12#else
13# define MIN_KERNEL_ALIGN_LG2 (PAGE_SHIFT + THREAD_SIZE_ORDER)
14#endif
15#define MIN_KERNEL_ALIGN (_AC(1, UL) << MIN_KERNEL_ALIGN_LG2)
16
17#if (CONFIG_PHYSICAL_ALIGN & (CONFIG_PHYSICAL_ALIGN-1)) || \
18 (CONFIG_PHYSICAL_ALIGN < MIN_KERNEL_ALIGN)
19# error "Invalid value for CONFIG_PHYSICAL_ALIGN"
20#endif
21
22#if defined(CONFIG_KERNEL_BZIP2)
23# define BOOT_HEAP_SIZE 0x400000
24#elif defined(CONFIG_KERNEL_ZSTD)
25/*
26 * Zstd needs to allocate the ZSTD_DCtx in order to decompress the kernel.
27 * The ZSTD_DCtx is ~160KB, so set the heap size to 192KB because it is a
28 * round number and to allow some slack.
29 */
30# define BOOT_HEAP_SIZE 0x30000
31#else
32# define BOOT_HEAP_SIZE 0x10000
33#endif
34
35#ifdef CONFIG_X86_64
36# define BOOT_STACK_SIZE 0x4000
37
38/*
39 * Used by decompressor's startup_32() to allocate page tables for identity
40 * mapping of the 4G of RAM in 4-level paging mode:
41 * - 1 level4 table;
42 * - 1 level3 table;
43 * - 4 level2 table that maps everything with 2M pages;
44 *
45 * The additional level5 table needed for 5-level paging is allocated from
46 * trampoline_32bit memory.
47 */
48# define BOOT_INIT_PGT_SIZE (6*4096)
49
50/*
51 * Total number of page tables kernel_add_identity_map() can allocate,
52 * including page tables consumed by startup_32().
53 *
54 * Worst-case scenario:
55 * - 5-level paging needs 1 level5 table;
56 * - KASLR needs to map kernel, boot_params, cmdline and randomized kernel,
57 * assuming all of them cross 256T boundary:
58 * + 4*2 level4 table;
59 * + 4*2 level3 table;
60 * + 4*2 level2 table;
61 * - X86_VERBOSE_BOOTUP needs to map the first 2M (video RAM):
62 * + 1 level4 table;
63 * + 1 level3 table;
64 * + 1 level2 table;
65 * Total: 28 tables
66 *
67 * Add 4 spare table in case decompressor touches anything beyond what is
68 * accounted above. Warn if it happens.
69 */
70# define BOOT_PGT_SIZE_WARN (28*4096)
71# define BOOT_PGT_SIZE (32*4096)
72
73#else /* !CONFIG_X86_64 */
74# define BOOT_STACK_SIZE 0x1000
75#endif
76
77#define TRAMPOLINE_32BIT_SIZE (2 * PAGE_SIZE)
78
79#define TRAMPOLINE_32BIT_CODE_OFFSET PAGE_SIZE
80#define TRAMPOLINE_32BIT_CODE_SIZE 0xA0
81
82#ifndef __ASSEMBLER__
83extern unsigned int output_len;
84extern const unsigned long kernel_text_size;
85extern const unsigned long kernel_total_size;
86
87unsigned long decompress_kernel(unsigned char *outbuf, unsigned long virt_addr,
88 void (*error)(char *x));
89
90extern struct boot_params *boot_params_ptr;
91extern unsigned long *trampoline_32bit;
92extern const u16 trampoline_ljmp_imm_offset;
93
94void trampoline_32bit_src(void *trampoline, bool enable_5lvl);
95
96#endif
97
98#endif /* _ASM_X86_BOOT_H */
99

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