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0018 #include <linux/pe.h>
0019 #include <asm/segment.h>
0020 #include <asm/boot.h>
0021 #include <asm/page_types.h>
0022 #include <asm/setup.h>
0023 #include <asm/bootparam.h>
0024 #include "boot.h"
0025 #include "voffset.h"
0026 #include "zoffset.h"
0027
0028 BOOTSEG = 0x07C0
0029 SYSSEG = 0x1000
0030
0031 #ifndef SVGA_MODE
0032 #define SVGA_MODE ASK_VGA
0033 #endif
0034
0035 #ifndef ROOT_RDONLY
0036 #define ROOT_RDONLY 1
0037 #endif
0038
0039 .code16
0040 .section ".bstext", "ax"
0041
0042 .global bootsect_start
0043 bootsect_start:
0044 #ifdef CONFIG_EFI_STUB
0045 # "MZ", MS-DOS header
0046 .word MZ_MAGIC
0047 #endif
0048
0049 # Normalize the start address
0050 ljmp $BOOTSEG, $start2
0051
0052 start2:
0053 movw %cs, %ax
0054 movw %ax, %ds
0055 movw %ax, %es
0056 movw %ax, %ss
0057 xorw %sp, %sp
0058 sti
0059 cld
0060
0061 movw $bugger_off_msg, %si
0062
0063 msg_loop:
0064 lodsb
0065 andb %al, %al
0066 jz bs_die
0067 movb $0xe, %ah
0068 movw $7, %bx
0069 int $0x10
0070 jmp msg_loop
0071
0072 bs_die:
0073 # Allow the user to press a key, then reboot
0074 xorw %ax, %ax
0075 int $0x16
0076 int $0x19
0077
0078 # int 0x19 should never return. In case it does anyway,
0079 # invoke the BIOS reset code...
0080 ljmp $0xf000,$0xfff0
0081
0082 #ifdef CONFIG_EFI_STUB
0083 .org 0x3c
0084 #
0085 # Offset to the PE header.
0086 #
0087 .long pe_header
0088 #endif
0089
0090 .section ".bsdata", "a"
0091 bugger_off_msg:
0092 .ascii "Use a boot loader.\r\n"
0093 .ascii "\n"
0094 .ascii "Remove disk and press any key to reboot...\r\n"
0095 .byte 0
0096
0097 #ifdef CONFIG_EFI_STUB
0098 pe_header:
0099 .long PE_MAGIC
0100
0101 coff_header:
0102 #ifdef CONFIG_X86_32
0103 .set image_file_add_flags, IMAGE_FILE_32BIT_MACHINE
0104 .set pe_opt_magic, PE_OPT_MAGIC_PE32
0105 .word IMAGE_FILE_MACHINE_I386
0106 #else
0107 .set image_file_add_flags, 0
0108 .set pe_opt_magic, PE_OPT_MAGIC_PE32PLUS
0109 .word IMAGE_FILE_MACHINE_AMD64
0110 #endif
0111 .word section_count # nr_sections
0112 .long 0 # TimeDateStamp
0113 .long 0 # PointerToSymbolTable
0114 .long 1 # NumberOfSymbols
0115 .word section_table - optional_header # SizeOfOptionalHeader
0116 .word IMAGE_FILE_EXECUTABLE_IMAGE | \
0117 image_file_add_flags | \
0118 IMAGE_FILE_DEBUG_STRIPPED | \
0119 IMAGE_FILE_LINE_NUMS_STRIPPED # Characteristics
0120
0121 optional_header:
0122 .word pe_opt_magic
0123 .byte 0x02 # MajorLinkerVersion
0124 .byte 0x14 # MinorLinkerVersion
0125
0126 # Filled in by build.c
0127 .long 0 # SizeOfCode
0128
0129 .long 0 # SizeOfInitializedData
0130 .long 0 # SizeOfUninitializedData
0131
0132 # Filled in by build.c
0133 .long 0x0000 # AddressOfEntryPoint
0134
0135 .long 0x0200 # BaseOfCode
0136 #ifdef CONFIG_X86_32
0137 .long 0 # data
0138 #endif
0139
0140 extra_header_fields:
0141 # PE specification requires ImageBase to be 64k aligned
0142 .set image_base, (LOAD_PHYSICAL_ADDR + 0xffff) & ~0xffff
0143 #ifdef CONFIG_X86_32
0144 .long image_base # ImageBase
0145 #else
0146 .quad image_base # ImageBase
0147 #endif
0148 .long 0x20 # SectionAlignment
0149 .long 0x20 # FileAlignment
0150 .word 0 # MajorOperatingSystemVersion
0151 .word 0 # MinorOperatingSystemVersion
0152 .word LINUX_EFISTUB_MAJOR_VERSION # MajorImageVersion
0153 .word LINUX_EFISTUB_MINOR_VERSION # MinorImageVersion
0154 .word 0 # MajorSubsystemVersion
0155 .word 0 # MinorSubsystemVersion
0156 .long 0 # Win32VersionValue
0157
0158 #
0159 # The size of the bzImage is written in tools/build.c
0160 #
0161 .long 0 # SizeOfImage
0162
0163 .long 0x200 # SizeOfHeaders
0164 .long 0 # CheckSum
0165 .word IMAGE_SUBSYSTEM_EFI_APPLICATION # Subsystem (EFI application)
0166 #ifdef CONFIG_EFI_DXE_MEM_ATTRIBUTES
0167 .word IMAGE_DLL_CHARACTERISTICS_NX_COMPAT # DllCharacteristics
0168 #else
0169 .word 0 # DllCharacteristics
0170 #endif
0171 #ifdef CONFIG_X86_32
0172 .long 0 # SizeOfStackReserve
0173 .long 0 # SizeOfStackCommit
0174 .long 0 # SizeOfHeapReserve
0175 .long 0 # SizeOfHeapCommit
0176 #else
0177 .quad 0 # SizeOfStackReserve
0178 .quad 0 # SizeOfStackCommit
0179 .quad 0 # SizeOfHeapReserve
0180 .quad 0 # SizeOfHeapCommit
0181 #endif
0182 .long 0 # LoaderFlags
0183 .long (section_table - .) / 8 # NumberOfRvaAndSizes
0184
0185 .quad 0 # ExportTable
0186 .quad 0 # ImportTable
0187 .quad 0 # ResourceTable
0188 .quad 0 # ExceptionTable
0189 .quad 0 # CertificationTable
0190 .quad 0 # BaseRelocationTable
0191
0192 # Section table
0193 section_table:
0194 #
0195 # The offset & size fields are filled in by build.c.
0196 #
0197 .ascii ".setup"
0198 .byte 0
0199 .byte 0
0200 .long 0
0201 .long 0x0 # startup_{32,64}
0202 .long 0 # Size of initialized data
0203 # on disk
0204 .long 0x0 # startup_{32,64}
0205 .long 0 # PointerToRelocations
0206 .long 0 # PointerToLineNumbers
0207 .word 0 # NumberOfRelocations
0208 .word 0 # NumberOfLineNumbers
0209 .long IMAGE_SCN_CNT_CODE | \
0210 IMAGE_SCN_MEM_READ | \
0211 IMAGE_SCN_MEM_EXECUTE | \
0212 IMAGE_SCN_ALIGN_16BYTES # Characteristics
0213
0214 #
0215 # The EFI application loader requires a relocation section
0216 # because EFI applications must be relocatable. The .reloc
0217 # offset & size fields are filled in by build.c.
0218 #
0219 .ascii ".reloc"
0220 .byte 0
0221 .byte 0
0222 .long 0
0223 .long 0
0224 .long 0 # SizeOfRawData
0225 .long 0 # PointerToRawData
0226 .long 0 # PointerToRelocations
0227 .long 0 # PointerToLineNumbers
0228 .word 0 # NumberOfRelocations
0229 .word 0 # NumberOfLineNumbers
0230 .long IMAGE_SCN_CNT_INITIALIZED_DATA | \
0231 IMAGE_SCN_MEM_READ | \
0232 IMAGE_SCN_MEM_DISCARDABLE | \
0233 IMAGE_SCN_ALIGN_1BYTES # Characteristics
0234
0235 #ifdef CONFIG_EFI_MIXED
0236 #
0237 # The offset & size fields are filled in by build.c.
0238 #
0239 .asciz ".compat"
0240 .long 0
0241 .long 0x0
0242 .long 0 # Size of initialized data
0243 # on disk
0244 .long 0x0
0245 .long 0 # PointerToRelocations
0246 .long 0 # PointerToLineNumbers
0247 .word 0 # NumberOfRelocations
0248 .word 0 # NumberOfLineNumbers
0249 .long IMAGE_SCN_CNT_INITIALIZED_DATA | \
0250 IMAGE_SCN_MEM_READ | \
0251 IMAGE_SCN_MEM_DISCARDABLE | \
0252 IMAGE_SCN_ALIGN_1BYTES # Characteristics
0253 #endif
0254
0255 #
0256 # The offset & size fields are filled in by build.c.
0257 #
0258 .ascii ".text"
0259 .byte 0
0260 .byte 0
0261 .byte 0
0262 .long 0
0263 .long 0x0 # startup_{32,64}
0264 .long 0 # Size of initialized data
0265 # on disk
0266 .long 0x0 # startup_{32,64}
0267 .long 0 # PointerToRelocations
0268 .long 0 # PointerToLineNumbers
0269 .word 0 # NumberOfRelocations
0270 .word 0 # NumberOfLineNumbers
0271 .long IMAGE_SCN_CNT_CODE | \
0272 IMAGE_SCN_MEM_READ | \
0273 IMAGE_SCN_MEM_EXECUTE | \
0274 IMAGE_SCN_ALIGN_16BYTES # Characteristics
0275
0276 .set section_count, (. - section_table) / 40
0277 #endif
0278
0279 # Kernel attributes; used by setup. This is part 1 of the
0280 # header, from the old boot sector.
0281
0282 .section ".header", "a"
0283 .globl sentinel
0284 sentinel: .byte 0xff, 0xff
0285
0286 .globl hdr
0287 hdr:
0288 setup_sects: .byte 0
0289 root_flags: .word ROOT_RDONLY
0290 syssize: .long 0
0291 ram_size: .word 0
0292 vid_mode: .word SVGA_MODE
0293 root_dev: .word 0
0294 boot_flag: .word 0xAA55
0295
0296 # offset 512, entry point
0297
0298 .globl _start
0299 _start:
0300 # Explicitly enter this as bytes, or the assembler
0301 # tries to generate a 3-byte jump here, which causes
0302 # everything else to push off to the wrong offset.
0303 .byte 0xeb # short (2-byte) jump
0304 .byte start_of_setup-1f
0305 1:
0306
0307 # Part 2 of the header, from the old setup.S
0308
0309 .ascii "HdrS" # header signature
0310 .word 0x020f # header version number (>= 0x0105)
0311 # or else old loadlin-1.5 will fail)
0312 .globl realmode_swtch
0313 realmode_swtch: .word 0, 0 # default_switch, SETUPSEG
0314 start_sys_seg: .word SYSSEG # obsolete and meaningless, but just
0315 # in case something decided to "use" it
0316 .word kernel_version-512 # pointing to kernel version string
0317 # above section of header is compatible
0318 # with loadlin-1.5 (header v1.5). Don't
0319 # change it.
0320
0321 type_of_loader: .byte 0 # 0 means ancient bootloader, newer
0322 # bootloaders know to change this.
0323 # See Documentation/x86/boot.rst for
0324 # assigned ids
0325
0326 # flags, unused bits must be zero (RFU) bit within loadflags
0327 loadflags:
0328 .byte LOADED_HIGH # The kernel is to be loaded high
0329
0330 setup_move_size: .word 0x8000 # size to move, when setup is not
0331 # loaded at 0x90000. We will move setup
0332 # to 0x90000 then just before jumping
0333 # into the kernel. However, only the
0334 # loader knows how much data behind
0335 # us also needs to be loaded.
0336
0337 code32_start: # here loaders can put a different
0338 # start address for 32-bit code.
0339 .long 0x100000 # 0x100000 = default for big kernel
0340
0341 ramdisk_image: .long 0 # address of loaded ramdisk image
0342 # Here the loader puts the 32-bit
0343 # address where it loaded the image.
0344 # This only will be read by the kernel.
0345
0346 ramdisk_size: .long 0 # its size in bytes
0347
0348 bootsect_kludge:
0349 .long 0 # obsolete
0350
0351 heap_end_ptr: .word _end+STACK_SIZE-512
0352 # (Header version 0x0201 or later)
0353 # space from here (exclusive) down to
0354 # end of setup code can be used by setup
0355 # for local heap purposes.
0356
0357 ext_loader_ver:
0358 .byte 0 # Extended boot loader version
0359 ext_loader_type:
0360 .byte 0 # Extended boot loader type
0361
0362 cmd_line_ptr: .long 0 # (Header version 0x0202 or later)
0363 # If nonzero, a 32-bit pointer
0364 # to the kernel command line.
0365 # The command line should be
0366 # located between the start of
0367 # setup and the end of low
0368 # memory (0xa0000), or it may
0369 # get overwritten before it
0370 # gets read. If this field is
0371 # used, there is no longer
0372 # anything magical about the
0373 # 0x90000 segment; the setup
0374 # can be located anywhere in
0375 # low memory 0x10000 or higher.
0376
0377 initrd_addr_max: .long 0x7fffffff
0378 # (Header version 0x0203 or later)
0379 # The highest safe address for
0380 # the contents of an initrd
0381 # The current kernel allows up to 4 GB,
0382 # but leave it at 2 GB to avoid
0383 # possible bootloader bugs.
0384
0385 kernel_alignment: .long CONFIG_PHYSICAL_ALIGN #physical addr alignment
0386 #required for protected mode
0387 #kernel
0388 #ifdef CONFIG_RELOCATABLE
0389 relocatable_kernel: .byte 1
0390 #else
0391 relocatable_kernel: .byte 0
0392 #endif
0393 min_alignment: .byte MIN_KERNEL_ALIGN_LG2 # minimum alignment
0394
0395 xloadflags:
0396 #ifdef CONFIG_X86_64
0397 # define XLF0 XLF_KERNEL_64
0398 #else
0399 # define XLF0 0
0400 #endif
0401
0402 #if defined(CONFIG_RELOCATABLE) && defined(CONFIG_X86_64)
0403
0404 # define XLF1 XLF_CAN_BE_LOADED_ABOVE_4G
0405 #else
0406 # define XLF1 0
0407 #endif
0408
0409 #ifdef CONFIG_EFI_STUB
0410 # ifdef CONFIG_EFI_MIXED
0411 # define XLF23 (XLF_EFI_HANDOVER_32|XLF_EFI_HANDOVER_64)
0412 # else
0413 # ifdef CONFIG_X86_64
0414 # define XLF23 XLF_EFI_HANDOVER_64
0415 # else
0416 # define XLF23 XLF_EFI_HANDOVER_32
0417 # endif
0418 # endif
0419 #else
0420 # define XLF23 0
0421 #endif
0422
0423 #if defined(CONFIG_X86_64) && defined(CONFIG_EFI) && defined(CONFIG_KEXEC_CORE)
0424 # define XLF4 XLF_EFI_KEXEC
0425 #else
0426 # define XLF4 0
0427 #endif
0428
0429 #ifdef CONFIG_X86_64
0430 #ifdef CONFIG_X86_5LEVEL
0431 #define XLF56 (XLF_5LEVEL|XLF_5LEVEL_ENABLED)
0432 #else
0433 #define XLF56 XLF_5LEVEL
0434 #endif
0435 #else
0436 #define XLF56 0
0437 #endif
0438
0439 .word XLF0 | XLF1 | XLF23 | XLF4 | XLF56
0440
0441 cmdline_size: .long COMMAND_LINE_SIZE-1 #length of the command line,
0442 #added with boot protocol
0443 #version 2.06
0444
0445 hardware_subarch: .long 0 # subarchitecture, added with 2.07
0446 # default to 0 for normal x86 PC
0447
0448 hardware_subarch_data: .quad 0
0449
0450 payload_offset: .long ZO_input_data
0451 payload_length: .long ZO_z_input_len
0452
0453 setup_data: .quad 0 # 64-bit physical pointer to
0454 # single linked list of
0455 # struct setup_data
0456
0457 pref_address: .quad LOAD_PHYSICAL_ADDR # preferred load addr
0458
0459 #
0460 # Getting to provably safe in-place decompression is hard. Worst case
0461 # behaviours need to be analyzed. Here let's take the decompression of
0462 # a gzip-compressed kernel as example, to illustrate it:
0463 #
0464 # The file layout of gzip compressed kernel is:
0465 #
0466 # magic[2]
0467 # method[1]
0468 # flags[1]
0469 # timestamp[4]
0470 # extraflags[1]
0471 # os[1]
0472 # compressed data blocks[N]
0473 # crc[4] orig_len[4]
0474 #
0475 # ... resulting in +18 bytes overhead of uncompressed data.
0476 #
0477 # (For more information, please refer to RFC 1951 and RFC 1952.)
0478 #
0479 # Files divided into blocks
0480 # 1 bit (last block flag)
0481 # 2 bits (block type)
0482 #
0483 # 1 block occurs every 32K -1 bytes or when there 50% compression
0484 # has been achieved. The smallest block type encoding is always used.
0485 #
0486 # stored:
0487 # 32 bits length in bytes.
0488 #
0489 # fixed:
0490 # magic fixed tree.
0491 # symbols.
0492 #
0493 # dynamic:
0494 # dynamic tree encoding.
0495 # symbols.
0496 #
0497 #
0498 # The buffer for decompression in place is the length of the uncompressed
0499 # data, plus a small amount extra to keep the algorithm safe. The
0500 # compressed data is placed at the end of the buffer. The output pointer
0501 # is placed at the start of the buffer and the input pointer is placed
0502 # where the compressed data starts. Problems will occur when the output
0503 # pointer overruns the input pointer.
0504 #
0505 # The output pointer can only overrun the input pointer if the input
0506 # pointer is moving faster than the output pointer. A condition only
0507 # triggered by data whose compressed form is larger than the uncompressed
0508 # form.
0509 #
0510 # The worst case at the block level is a growth of the compressed data
0511 # of 5 bytes per 32767 bytes.
0512 #
0513 # The worst case internal to a compressed block is very hard to figure.
0514 # The worst case can at least be bounded by having one bit that represents
0515 # 32764 bytes and then all of the rest of the bytes representing the very
0516 # very last byte.
0517 #
0518 # All of which is enough to compute an amount of extra data that is required
0519 # to be safe. To avoid problems at the block level allocating 5 extra bytes
0520 # per 32767 bytes of data is sufficient. To avoid problems internal to a
0521 # block adding an extra 32767 bytes (the worst case uncompressed block size)
0522 # is sufficient, to ensure that in the worst case the decompressed data for
0523 # block will stop the byte before the compressed data for a block begins.
0524 # To avoid problems with the compressed data's meta information an extra 18
0525 # bytes are needed. Leading to the formula:
0526 #
0527 # extra_bytes = (uncompressed_size >> 12) + 32768 + 18
0528 #
0529 # Adding 8 bytes per 32K is a bit excessive but much easier to calculate.
0530 # Adding 32768 instead of 32767 just makes for round numbers.
0531 #
0532 # Above analysis is for decompressing gzip compressed kernel only. Up to
0533 # now 6 different decompressor are supported all together. And among them
0534 # xz stores data in chunks and has maximum chunk of 64K. Hence safety
0535 # margin should be updated to cover all decompressors so that we don't
0536 # need to deal with each of them separately. Please check
0537 # the description in lib/decompressor_xxx.c for specific information.
0538 #
0539 # extra_bytes = (uncompressed_size >> 12) + 65536 + 128
0540 #
0541 # LZ4 is even worse: data that cannot be further compressed grows by 0.4%,
0542 # or one byte per 256 bytes. OTOH, we can safely get rid of the +128 as
0543 # the size-dependent part now grows so fast.
0544 #
0545 # extra_bytes = (uncompressed_size >> 8) + 65536
0546 #
0547 # ZSTD compressed data grows by at most 3 bytes per 128K, and only has a 22
0548 # byte fixed overhead but has a maximum block size of 128K, so it needs a
0549 # larger margin.
0550 #
0551 # extra_bytes = (uncompressed_size >> 8) + 131072
0552
0553 #define ZO_z_extra_bytes ((ZO_z_output_len >> 8) + 131072)
0554 #if ZO_z_output_len > ZO_z_input_len
0555 # define ZO_z_extract_offset (ZO_z_output_len + ZO_z_extra_bytes - \
0556 ZO_z_input_len)
0557 #else
0558 # define ZO_z_extract_offset ZO_z_extra_bytes
0559 #endif
0560
0561
0562
0563
0564
0565
0566 #if (ZO__ehead - ZO_startup_32) > ZO_z_extract_offset
0567 # define ZO_z_min_extract_offset ((ZO__ehead - ZO_startup_32 + 4095) & ~4095)
0568 #else
0569 # define ZO_z_min_extract_offset ((ZO_z_extract_offset + 4095) & ~4095)
0570 #endif
0571
0572 #define ZO_INIT_SIZE (ZO__end - ZO_startup_32 + ZO_z_min_extract_offset)
0573
0574 #define VO_INIT_SIZE (VO__end - VO__text)
0575 #if ZO_INIT_SIZE > VO_INIT_SIZE
0576 # define INIT_SIZE ZO_INIT_SIZE
0577 #else
0578 # define INIT_SIZE VO_INIT_SIZE
0579 #endif
0580
0581 init_size: .long INIT_SIZE # kernel initialization size
0582 handover_offset: .long 0 # Filled in by build.c
0583 kernel_info_offset: .long 0 # Filled in by build.c
0584
0585 # End of setup header #####################################################
0586
0587 .section ".entrytext", "ax"
0588 start_of_setup:
0589 # Force %es = %ds
0590 movw %ds, %ax
0591 movw %ax, %es
0592 cld
0593
0594 # Apparently some ancient versions of LILO invoked the kernel with %ss != %ds,
0595 # which happened to work by accident for the old code. Recalculate the stack
0596 # pointer if %ss is invalid. Otherwise leave it alone, LOADLIN sets up the
0597 # stack behind its own code, so we can't blindly put it directly past the heap.
0598
0599 movw %ss, %dx
0600 cmpw %ax, %dx # %ds == %ss?
0601 movw %sp, %dx
0602 je 2f # -> assume %sp is reasonably set
0603
0604 # Invalid %ss, make up a new stack
0605 movw $_end, %dx
0606 testb $CAN_USE_HEAP, loadflags
0607 jz 1f
0608 movw heap_end_ptr, %dx
0609 1: addw $STACK_SIZE, %dx
0610 jnc 2f
0611 xorw %dx, %dx # Prevent wraparound
0612
0613 2: # Now %dx should point to the end of our stack space
0614 andw $~3, %dx # dword align (might as well...)
0615 jnz 3f
0616 movw $0xfffc, %dx # Make sure we're not zero
0617 3: movw %ax, %ss
0618 movzwl %dx, %esp # Clear upper half of %esp
0619 sti # Now we should have a working stack
0620
0621 # We will have entered with %cs = %ds+0x20, normalize %cs so
0622 # it is on par with the other segments.
0623 pushw %ds
0624 pushw $6f
0625 lretw
0626 6:
0627
0628 # Check signature at end of setup
0629 cmpl $0x5a5aaa55, setup_sig
0630 jne setup_bad
0631
0632 # Zero the bss
0633 movw $__bss_start, %di
0634 movw $_end+3, %cx
0635 xorl %eax, %eax
0636 subw %di, %cx
0637 shrw $2, %cx
0638 rep; stosl
0639
0640 # Jump to C code (should not return)
0641 calll main
0642
0643 # Setup corrupt somehow...
0644 setup_bad:
0645 movl $setup_corrupt, %eax
0646 calll puts
0647 # Fall through...
0648
0649 .globl die
0650 .type die, @function
0651 die:
0652 hlt
0653 jmp die
0654
0655 .size die, .-die
0656
0657 .section ".initdata", "a"
0658 setup_corrupt:
0659 .byte 7
0660 .string "No setup signature found...\n"
