1#ifndef _BZIMAGE_H
2#define _BZIMAGE_H
3
4FILE_LICENCE ( GPL2_OR_LATER );
5
6#include <stdint.h>
7
8/**
9 * A bzImage header
10 *
11 * As documented in Documentation/i386/boot.txt
12 */
13struct bzimage_header {
14	/** The size of the setup in sectors
15	 *
16	 * If this field contains 0, assume it contains 4.
17	 */
18	uint8_t setup_sects;
19	/** If set, the root is mounted readonly */
20	uint16_t root_flags;
21	/** DO NOT USE - for bootsect.S use only */
22	uint16_t syssize;
23	/** DO NOT USE - obsolete */
24	uint16_t swap_dev;
25	/** DO NOT USE - for bootsect.S use only */
26	uint16_t ram_size;
27	/** Video mode control */
28	uint16_t vid_mode;
29	/** Default root device number */
30	uint16_t root_dev;
31	/** 0xAA55 magic number */
32	uint16_t boot_flag;
33	/** Jump instruction */
34	uint16_t jump;
35	/** Magic signature "HdrS" */
36	uint32_t header;
37	/** Boot protocol version supported */
38	uint16_t version;
39	/** Boot loader hook (see below) */
40	uint32_t realmode_swtch;
41	/** The load-low segment (0x1000) (obsolete) */
42	uint16_t start_sys;
43	/** Pointer to kernel version string */
44	uint16_t kernel_version;
45	/** Boot loader identifier */
46	uint8_t type_of_loader;
47	/** Boot protocol option flags */
48	uint8_t loadflags;
49	/** Move to high memory size (used with hooks) */
50	uint16_t setup_move_size;
51	/** Boot loader hook (see below) */
52	uint32_t code32_start;
53	/** initrd load address (set by boot loader) */
54	uint32_t ramdisk_image;
55	/** initrd size (set by boot loader) */
56	uint32_t ramdisk_size;
57	/** DO NOT USE - for bootsect.S use only */
58	uint32_t bootsect_kludge;
59	/** Free memory after setup end */
60	uint16_t heap_end_ptr;
61	/** Unused */
62	uint16_t pad1;
63	/** 32-bit pointer to the kernel command line */
64	uint32_t cmd_line_ptr;
65	/** Highest legal initrd address */
66	uint32_t initrd_addr_max;
67	/** Physical addr alignment required for kernel	*/
68	uint32_t kernel_alignment;
69	/** Whether kernel is relocatable or not */
70	uint8_t relocatable_kernel;
71	/** Unused */
72	uint8_t pad2[3];
73	/** Maximum size of the kernel command line */
74	uint32_t cmdline_size;
75} __attribute__ (( packed ));
76
77/** Offset of bzImage header within kernel image */
78#define BZI_HDR_OFFSET 0x1f1
79
80/** bzImage boot flag value */
81#define BZI_BOOT_FLAG 0xaa55
82
83/** bzImage magic signature value */
84#define BZI_SIGNATURE 0x53726448
85
86/** bzImage boot loader identifier for Etherboot */
87#define BZI_LOADER_TYPE_ETHERBOOT 0x40
88
89/** bzImage boot loader identifier for gPXE
90 *
91 * We advertise ourselves as Etherboot version 6.
92 */
93#define BZI_LOADER_TYPE_GPXE ( BZI_LOADER_TYPE_ETHERBOOT | 0x06 )
94
95/** bzImage "load high" flag */
96#define BZI_LOAD_HIGH 0x01
97
98/** Load address for high-loaded kernels */
99#define BZI_LOAD_HIGH_ADDR 0x100000
100
101/** Load address for low-loaded kernels */
102#define BZI_LOAD_LOW_ADDR 0x10000
103
104/** bzImage "kernel can use heap" flag */
105#define BZI_CAN_USE_HEAP 0x80
106
107/** bzImage special video mode "normal" */
108#define BZI_VID_MODE_NORMAL 0xffff
109
110/** bzImage special video mode "ext" */
111#define BZI_VID_MODE_EXT 0xfffe
112
113/** bzImage special video mode "ask" */
114#define BZI_VID_MODE_ASK 0xfffd
115
116/** bzImage maximum initrd address for versions < 2.03 */
117#define BZI_INITRD_MAX 0x37ffffff
118
119/** bzImage command-line structure used by older kernels */
120struct bzimage_cmdline {
121	/** Magic signature */
122	uint16_t magic;
123	/** Offset to command line */
124	uint16_t offset;
125} __attribute__ (( packed ));
126
127/** Offset of bzImage command-line structure within kernel image */
128#define BZI_CMDLINE_OFFSET 0x20
129
130/** bzImage command line present magic marker value */
131#define BZI_CMDLINE_MAGIC 0xa33f
132
133/** Assumed size of real-mode portion (including .bss) */
134#define BZI_ASSUMED_RM_SIZE 0x8000
135
136/** Amount of stack space to provide */
137#define BZI_STACK_SIZE 0x1000
138
139/** Maximum size of command line */
140#define BZI_CMDLINE_SIZE 0x100
141
142#endif /* _BZIMAGE_H */
143