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Diffstat (limited to 'Documentation/i386/zero-page.txt')
| -rw-r--r-- | Documentation/i386/zero-page.txt | 122 |
1 files changed, 27 insertions, 95 deletions
diff --git a/Documentation/i386/zero-page.txt b/Documentation/i386/zero-page.txt index 6c0817c45683..169ad423a3d1 100644 --- a/Documentation/i386/zero-page.txt +++ b/Documentation/i386/zero-page.txt @@ -1,99 +1,31 @@ ---------------------------------------------------------------------------- -!!!!!!!!!!!!!!!WARNING!!!!!!!! -The zero page is a kernel internal data structure, not a stable ABI. It might change -without warning and the kernel has no way to detect old version of it. -If you're writing some external code like a boot loader you should only use -the stable versioned real mode boot protocol described in boot.txt. Otherwise the kernel -might break you at any time. -!!!!!!!!!!!!!WARNING!!!!!!!!!!! ----------------------------------------------------------------------------- +The additional fields in struct boot_params as a part of 32-bit boot +protocol of kernel. These should be filled by bootloader or 16-bit +real-mode setup code of the kernel. References/settings to it mainly +are in: -Summary of boot_params layout (kernel point of view) - ( collected by Hans Lermen and Martin Mares ) - -The contents of boot_params are used to pass parameters from the -16-bit realmode code of the kernel to the 32-bit part. References/settings -to it mainly are in: + include/asm-x86/bootparam.h - arch/i386/boot/setup.S - arch/i386/boot/video.S - arch/i386/kernel/head.S - arch/i386/kernel/setup.c - -Offset Type Description ------- ---- ----------- - 0 32 bytes struct screen_info, SCREEN_INFO - ATTENTION, overlaps the following !!! - 2 unsigned short EXT_MEM_K, extended memory size in Kb (from int 0x15) - 0x20 unsigned short CL_MAGIC, commandline magic number (=0xA33F) - 0x22 unsigned short CL_OFFSET, commandline offset - Address of commandline is calculated: - 0x90000 + contents of CL_OFFSET - (only taken, when CL_MAGIC = 0xA33F) - 0x40 20 bytes struct apm_bios_info, APM_BIOS_INFO - 0x60 16 bytes Intel SpeedStep (IST) BIOS support information - 0x80 16 bytes hd0-disk-parameter from intvector 0x41 - 0x90 16 bytes hd1-disk-parameter from intvector 0x46 +Offset Proto Name Meaning +/Size - 0xa0 16 bytes System description table truncated to 16 bytes. - ( struct sys_desc_table_struct ) - 0xb0 - 0x13f Free. Add more parameters here if you really need them. - 0x140- 0x1be EDID_INFO Video mode setup - -0x1c4 unsigned long EFI system table pointer -0x1c8 unsigned long EFI memory descriptor size -0x1cc unsigned long EFI memory descriptor version -0x1d0 unsigned long EFI memory descriptor map pointer -0x1d4 unsigned long EFI memory descriptor map size -0x1e0 unsigned long ALT_MEM_K, alternative mem check, in Kb -0x1e4 unsigned long Scratch field for the kernel setup code -0x1e8 char number of entries in E820MAP (below) -0x1e9 unsigned char number of entries in EDDBUF (below) -0x1ea unsigned char number of entries in EDD_MBR_SIG_BUFFER (below) -0x1f1 char size of setup.S, number of sectors -0x1f2 unsigned short MOUNT_ROOT_RDONLY (if !=0) -0x1f4 unsigned short size of compressed kernel-part in the - (b)zImage-file (in 16 byte units, rounded up) -0x1f6 unsigned short swap_dev (unused AFAIK) -0x1f8 unsigned short RAMDISK_FLAGS -0x1fa unsigned short VGA-Mode (old one) -0x1fc unsigned short ORIG_ROOT_DEV (high=Major, low=minor) -0x1ff char AUX_DEVICE_INFO - -0x200 short jump to start of setup code aka "reserved" field. -0x202 4 bytes Signature for SETUP-header, ="HdrS" -0x206 unsigned short Version number of header format - Current version is 0x0201... -0x208 8 bytes (used by setup.S for communication with boot loaders, - look there) -0x210 char LOADER_TYPE, = 0, old one - else it is set by the loader: - 0xTV: T=0 for LILO - 1 for Loadlin - 2 for bootsect-loader - 3 for SYSLINUX - 4 for ETHERBOOT - 5 for ELILO - 7 for GRuB - 8 for U-BOOT - 9 for Xen - V = version -0x211 char loadflags: - bit0 = 1: kernel is loaded high (bzImage) - bit7 = 1: Heap and pointer (see below) set by boot - loader. -0x212 unsigned short (setup.S) -0x214 unsigned long KERNEL_START, where the loader started the kernel -0x218 unsigned long INITRD_START, address of loaded ramdisk image -0x21c unsigned long INITRD_SIZE, size in bytes of ramdisk image -0x220 4 bytes (setup.S) -0x224 unsigned short setup.S heap end pointer -0x226 unsigned short zero_pad -0x228 unsigned long cmd_line_ptr -0x22c unsigned long ramdisk_max -0x230 16 bytes trampoline -0x290 - 0x2cf EDD_MBR_SIG_BUFFER (edd.S) -0x2d0 - 0xd00 E820MAP -0xd00 - 0xeff EDDBUF (edd.S) for disk signature read sector -0xd00 - 0xeeb EDDBUF (edd.S) for edd data +000/040 ALL screen_info Text mode or frame buffer information + (struct screen_info) +040/014 ALL apm_bios_info APM BIOS information (struct apm_bios_info) +060/010 ALL ist_info Intel SpeedStep (IST) BIOS support information + (struct ist_info) +080/010 ALL hd0_info hd0 disk parameter, OBSOLETE!! +090/010 ALL hd1_info hd1 disk parameter, OBSOLETE!! +0A0/010 ALL sys_desc_table System description table (struct sys_desc_table) +140/080 ALL edid_info Video mode setup (struct edid_info) +1C0/020 ALL efi_info EFI 32 information (struct efi_info) +1E0/004 ALL alk_mem_k Alternative mem check, in KB +1E4/004 ALL scratch Scratch field for the kernel setup code +1E8/001 ALL e820_entries Number of entries in e820_map (below) +1E9/001 ALL eddbuf_entries Number of entries in eddbuf (below) +1EA/001 ALL edd_mbr_sig_buf_entries Number of entries in edd_mbr_sig_buffer + (below) +290/040 ALL edd_mbr_sig_buffer EDD MBR signatures +2D0/A00 ALL e820_map E820 memory map table + (array of struct e820entry) +D00/1EC ALL eddbuf EDD data (array of struct edd_info) |