xref: /linux/arch/x86/include/asm/boot.h (revision 249ebf3f65f8530beb2cbfb91bff1d83ba88d23c)
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 #ifndef __ASSEMBLY__
78 extern unsigned int output_len;
79 extern const unsigned long kernel_text_size;
80 extern const unsigned long kernel_total_size;
81 
82 unsigned long decompress_kernel(unsigned char *outbuf, unsigned long virt_addr,
83 				void (*error)(char *x));
84 
85 extern struct boot_params *boot_params_ptr;
86 #endif
87 
88 #endif /* _ASM_X86_BOOT_H */
89