xref: /linux/arch/x86/include/asm/boot.h (revision 7255fcc80d4b525cc10cfaaf7f485830d4ed2000)
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__
83 extern unsigned int output_len;
84 extern const unsigned long kernel_text_size;
85 extern const unsigned long kernel_total_size;
86 
87 unsigned long decompress_kernel(unsigned char *outbuf, unsigned long virt_addr,
88 				void (*error)(char *x));
89 
90 extern struct boot_params *boot_params_ptr;
91 #endif
92 
93 #endif /* _ASM_X86_BOOT_H */
94