x86/boot/header.S

1 /* SPDX-License-Identifier: GPL-2.0 */
12  * BIG FAT NOTE: We're in real mode using 64k segments.  Therefore segment
28 BOOTSEG		= 0x07C0		/* original address of boot-sector */
45 	# "MZ", MS-DOS header
70 	.word	section_table - optional_header	# SizeOfOptionalHeader
78 	.byte	0x02				# MajorLinkerVersion
79 	.byte	0x14				# MinorLinkerVersion
83 	.long	ZO__end - ZO__data		# SizeOfInitializedData
131 	.long	(section_table - .) / 8		# NumberOfRvaAndSizes
143 	.byte	0
144 	.byte	0
145 	.long	pecompat_fstart - salign 	# VirtualSize
147 	.long	pecompat_fstart - salign	# SizeOfRawData
169 	 * Put the IA-32 machine type and the associated entry point address in
177 	.byte	0x1				# Version
178 	.byte	8				# Size
181 	.byte	0x0				# Sentinel
187 	.byte	0
188 	.byte	0
189 	.byte	0
204 	.long	ZO__end - ZO__data		# VirtualSize
206 	.long	ZO__edata - ZO__data		# SizeOfRawData
214 	.set	section_count, (. - section_table) / 40
222 sentinel:	.byte 0xff, 0xff        /* Used to detect broken loaders */
226 		.byte setup_sects - 1
239 		# tries to generate a 3-byte jump here, which causes
241 		.byte	0xeb		# short (2-byte) jump
242 		.byte	start_of_setup-1f
249 					# or else old loadlin-1.5 will fail)
254 		.word	kernel_version-512 # pointing to kernel version string
256 					# with loadlin-1.5 (header v1.5). Don't
259 type_of_loader:	.byte	0		# 0 means ancient bootloader, newer
266 		.byte	LOADED_HIGH	# The kernel is to be loaded high
276 					# start address for 32-bit code.
280 					# Here the loader puts the 32-bit
289 heap_end_ptr:	.word	_end+STACK_SIZE-512
296 		.byte	0		# Extended boot loader version
298 		.byte	0		# Extended boot loader type
301 					# If nonzero, a 32-bit pointer
327 relocatable_kernel:    .byte 1
329 relocatable_kernel:    .byte 0
331 min_alignment:		.byte MIN_KERNEL_ALIGN_LG2	# minimum alignment
335 # define XLF0 XLF_KERNEL_64			/* 64-bit kernel */
352 #   define XLF23 XLF_EFI_HANDOVER_64		/* 64-bit EFI handover ok */
354 #   define XLF23 XLF_EFI_HANDOVER_32		/* 32-bit EFI handover ok */
379 cmdline_size:   .long   COMMAND_LINE_SIZE-1     #length of the command line,
391 setup_data:		.quad 0			# 64-bit physical pointer to
398 # Getting to provably safe in-place decompression is hard. Worst case
400 # a gzip-compressed kernel as example, to illustrate it:
421 # 1 block occurs every 32K -1 bytes or when there 50% compression
454 # very last byte.
461 # block will stop the byte before the compressed data for a block begins.
472 # xz stores data in chunks and has maximum chunk of 64K. Hence safety
480 # or one byte per 256 bytes. OTOH, we can safely get rid of the +128 as
481 # the size-dependent part now grows so fast.
486 # byte fixed overhead but has a maximum block size of 128K, so it needs a
493 # define ZO_z_extract_offset	(ZO_z_output_len + ZO_z_extra_bytes - \
504 #if (ZO__ehead - ZO_startup_32) > ZO_z_extract_offset
505 # define ZO_z_min_extract_offset ((ZO__ehead - ZO_startup_32 + 4095) & ~4095)
510 #define ZO_INIT_SIZE	(ZO__end - ZO_startup_32 + ZO_z_min_extract_offset)
512 #define VO_INIT_SIZE	(VO__end - VO__text)
526 	.long		ZO_efi64_stub_entry - 0x200
528 	.if		ZO_efi32_stub_entry != ZO_efi64_stub_entry - 0x200
529 	.error		"32-bit and 64-bit EFI entry points do not match"
556 	je	2f		# -> assume %sp is reasonably set
609 	.size	die, .-die
613 	.byte	7