Lines Matching +full:mode +full:- +full:bootloader
1 .. SPDX-License-Identifier: GPL-2.0
12 real-mode DOS as a mainstream operating system.
28 Protocol 2.02 (Kernel 2.4.0-test3-pre3) New command line protocol.
31 safe for systems which use the EBDA from SMM or 32-bit
35 Protocol 2.03 (Kernel 2.4.18-pre1) Explicitly makes the highest possible
36 initrd address available to the bootloader.
40 Protocol 2.05 (Kernel 2.6.20) Make protected mode kernel relocatable.
54 Protocol 2.09 (Kernel 2.6.26) Added a field of 64-bit physical
68 Protocol 2.13 (Kernel 3.14) Support 32- and 64-bit flags being set in
69 xloadflags to support booting a 64-bit kernel from 32-bit
99 0A0000 +------------------------+
101 09A000 +------------------------+
103 | Stack/heap | For use by the kernel real-mode code.
104 098000 +------------------------+
105 | Kernel setup | The kernel real-mode code.
106 090200 +------------------------+
108 090000 +------------------------+
109 | Protected-mode kernel | The bulk of the kernel image.
110 010000 +------------------------+
111 | Boot loader | <- Boot sector entry point 0000:7C00
112 001000 +------------------------+
114 000800 +------------------------+
116 000600 +------------------------+
118 000000 +------------------------+
120 When using bzImage, the protected-mode kernel was relocated to
121 0x100000 ("high memory"), and the kernel real-mode block (boot sector,
127 It is desirable to keep the "memory ceiling" -- the highest point in
128 low memory touched by the boot loader -- as low as possible, since
146 | Protected-mode kernel |
147 100000 +------------------------+
149 0A0000 +------------------------+
153 X+10000 +------------------------+
154 | Stack/heap | For use by the kernel real-mode code.
155 X+08000 +------------------------+
156 | Kernel setup | The kernel real-mode code.
158 X +------------------------+
159 | Boot loader | <- Boot sector entry point 0000:7C00
160 001000 +------------------------+
162 000800 +------------------------+
164 000600 +------------------------+
166 000000 +------------------------+
171 The Real-Mode Kernel Header
179 real-mode code (boot sector and setup code) and then examine the
180 following header at offset 0x01f1. The real-mode code can total up to
191 01F4/4 2.04+(2) syssize The size of the 32-bit code in 16-byte paras
192 01F8/2 ALL ram_size DO NOT USE - for bootsect.S use only
193 01FA/2 ALL vid_mode Video mode control
200 020C/2 2.00+ start_sys_seg The load-low segment (0x1000) (obsolete)
208 0220/4 2.00+ bootsect_kludge DO NOT USE - for bootsect.S use only
212 0228/4 2.02+ cmd_line_ptr 32-bit pointer to the kernel command line
220 0240/8 2.07+ hardware_subarch_data Subarchitecture-specific data
223 0250/8 2.09+ setup_data 64-bit physical pointer to linked list
239 (3) Ignored, but safe to set, for boot protocols 2.02-2.09.
247 Real-mode kernel must be located at 0x90000.
258 For each field, some are information from the kernel to the bootloader
259 ("read"), some are expected to be filled out by the bootloader
261 bootloader ("modify").
277 The size of the setup code in 512-byte sectors. If this field is
278 0, the real value is 4. The real-mode code consists of the boot
279 sector (always one 512-byte sector) plus the setup code.
299 The size of the protected-mode code in units of 16-byte paragraphs.
397 If set to a nonzero value, contains a pointer to a NUL-terminated
398 human-readable kernel version number string, less 0x200. This can
426 four bits for the bootloader version.
430 type_of_loader <- 0xE4
431 ext_loader_type <- 0x05
432 ext_loader_ver <- 0x23
438 (0x00 reserved for pre-2.00 bootloader)
440 2 bootsect-loader
446 8 U-Boot
451 D kexec-tools
455 11 Minimal Linux Bootloader
456 <http://sebastian-plotz.blogspot.de>
461 Please contact <hpa@zytor.com> if you need a bootloader ID value assigned.
474 - If 0, the protected-mode code is loaded at 0x10000.
475 - If 1, the protected-mode code is loaded at 0x100000.
479 - Used internally by the compressed kernel to communicate
482 - If 1, KASLR enabled.
483 - If 0, KASLR disabled.
487 - If 0, print early messages.
488 - If 1, suppress early messages.
498 - This flag is obsolete.
511 Protocol: 2.00-2.01
514 When using protocol 2.00 or 2.01, if the real mode kernel is not
517 the kernel command line) moved in addition to the real-mode kernel
523 if the real-mode code is loaded at 0x90000.
532 The address to jump to in protected mode. This defaults to the load
540 2. if a bootloader which does not install a hook loads a
551 The 32-bit linear address of the initial ramdisk or ramfs. Leave at
580 Set this field to the offset (from the beginning of the real-mode
626 same 64K segment as the real-mode code itself.
672 If this field is nonzero, the protected-mode part of the kernel can
693 power-of-two alignment from kernel_alignment down to this alignment.
706 - If 1, this kernel has the legacy 64-bit entry point at 0x200.
710 - If 1, kernel/boot_params/cmdline/ramdisk can be above 4G.
714 - If 1, the kernel supports the 32-bit EFI handoff entry point
719 - If 1, the kernel supports the 64-bit EFI handoff entry point
724 - If 1, the kernel supports kexec EFI boot with EFI runtime support.
750 This field allows the bootloader to inform the kernel we are in one
763 Type: write (subarch-dependent)
779 If non-zero then this field contains the offset from the beginning
780 of the protected-mode code to the payload.
806 The 64-bit physical pointer to NULL terminated single linked list of
818 Where, the next is a 64-bit physical pointer to the next node of
830 and because it has a 32-bit length field. However, it is important that
877 kernel. A relocating bootloader should attempt to load at this
880 A non-relocatable kernel will unconditionally move itself and to run
925 in the uncompressed protected mode region.
942 a long time, for lack of alternatives and -- especially early on -- inertia.
944 available to a BIOS-based loader (setup_data is, though).
947 2-byte jump field, which doubles as a length field for the structure, combined
948 with the size of the "hole" in struct boot_params that a protected-mode loader
955 the kernel image, because it is .bss and has no image-provided content.
959 bootloader copying its contents anywhere, but that is OK; if it becomes
960 necessary it can still contain data items that an enabled bootloader would be
970 .long kernel_info_var_len_data - kernel_info
971 .long kernel_info_end - kernel_info
976 .long example_struct_end - example_struct
982 .long example_strings_end - example_strings
988 This way the kernel_info is self-contained blob.
991 Each variable size data header/magic can be any 4-character string,
1035 From boot protocol version 2.08 onwards the CRC-32 is calculated over
1050 The kernel command line is a null-terminated string. The maximum
1063 - At offset 0x0020 (word), "cmd_line_magic", enter the magic
1066 - At offset 0x0022 (word), "cmd_line_offset", enter the offset
1068 real-mode kernel).
1070 - The kernel command line *must* be within the memory region
1075 Memory Layout of The Real-Mode Code
1078 The real-mode code requires a stack/heap to be set up, as well as
1080 in the real-mode accessible memory in bottom megabyte.
1089 - When loading a zImage kernel ((loadflags & 0x01) == 0).
1090 - When loading a 2.01 or earlier boot protocol kernel.
1093 For the 2.00 and 2.01 boot protocols, the real-mode code
1096 real-mode code must be loaded at 0x90000.
1101 located in the same 64K segment as the real-mode setup code; it is
1105 The kernel command line should not be located below the real-mode
1113 mode segment.
1118 0x0000-0x7fff Real mode kernel
1119 0x8000-0xdfff Stack and heap
1120 0xe000-0xffff Kernel command line
1126 0x0000-0x7fff Real mode kernel
1127 0x8000-0x97ff Stack and heap
1128 0x9800-0x9fff Kernel command line
1133 unsigned long base_ptr; /* base address for real-mode segment */
1152 heap_end_ptr = heap_end - 0x200;
1173 /* A very old kernel MUST have its real-mode code
1177 /* Copy the real-mode kernel */
1186 (64-(setup_sects+1))*512);
1193 The 32-bit (non-real-mode) kernel starts at offset (setup_sects+1)*512
1205 the entire 0x10000-0x90000 range of memory. This means it is pretty
1206 much a requirement for these kernels to load the real-mode part at
1218 Documentation/admin-guide/kernel-parameters.rst to make sure they will not
1221 vga=<mode>
1222 <mode> here is either an integer (in C notation, either
1236 the bootloader!
1240 obviously bootloader-dependent, and some boot loaders
1244 user-specified command line:
1248 is obviously bootloader-dependent.
1254 recommended that they are located *first*, before the user-specified
1255 or configuration-specified command line. Otherwise, "init=/bin/sh"
1263 located at *segment* offset 0x20 from the start of the real mode
1264 kernel. This means that if you loaded your real-mode kernel code at
1267 At entry, ds = es = ss should point to the start of the real-mode
1283 /* Set up the real-mode kernel stack */
1294 a demand-loaded module!
1311 A 16-bit real mode far subroutine invoked immediately before
1312 entering protected mode. The default routine disables NMI, so
1316 A 32-bit flat-mode routine *jumped* to immediately after the
1317 transition to protected mode, but before the kernel is
1327 32-bit Boot Protocol
1331 LinuxBIOS, etc, and kexec, the 16-bit real mode setup code in kernel
1332 based on legacy BIOS can not be used, so a 32-bit boot protocol needs
1335 In 32-bit boot protocol, the first step in loading a Linux kernel
1346 boot_params as that of 16-bit boot protocol, the boot loader should
1348 described in chapter Documentation/arch/x86/zero-page.rst.
1351 32/64-bit kernel in the same way as that of 16-bit boot protocol.
1353 In 32-bit boot protocol, the kernel is started by jumping to the
1354 32-bit kernel entry point, which is the start address of loaded
1355 32/64-bit kernel.
1357 At entry, the CPU must be in 32-bit protected mode with paging
1365 64-bit Boot Protocol
1368 For machine with 64bit cpus and 64bit kernel, we could use 64bit bootloader
1369 and we need a 64-bit boot protocol.
1371 In 64-bit boot protocol, the first step in loading a Linux kernel
1382 boot_params as that of 16-bit boot protocol, the boot loader should
1384 in chapter Documentation/arch/x86/zero-page.rst.
1387 64-bit kernel in the same way as that of 16-bit boot protocol, but
1390 In 64-bit boot protocol, the kernel is started by jumping to the
1391 64-bit kernel entry point, which is the start address of loaded
1392 64-bit kernel plus 0x200.
1394 At entry, the CPU must be in 64-bit mode with paging enabled.
1410 which is hdr->handover_offset bytes from the beginning of
1424 firmware, 'table' is the EFI system table - these are the first two
1426 UEFI specification. 'bp' is the boot loader-allocated boot params.
1430 - hdr.cmd_line_ptr
1431 - hdr.ramdisk_image (if applicable)
1432 - hdr.ramdisk_size (if applicable)
1438 loading protocol (refer to [0] for an example of the bootloader side of
1440 bootloader regarding the internal representation of boot_params or any
1444 [0] https://github.com/u-boot/u-boot/commit/ec80b4735a593961fe701cc3a5d717d4739b0fd0