src/arch/i386/include/bzimage.h

   1 #ifndef _BZIMAGE_H
   2 #define _BZIMAGE_H
   3
   4 FILE_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  */
  13 struct 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 */
 120 struct 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 */