| /* |
| * header.S |
| * |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| * |
| * Based on bootsect.S and setup.S |
| * modified by more people than can be counted |
| * |
| * Rewritten as a common file by H. Peter Anvin (Apr 2007) |
| * |
| * BIG FAT NOTE: We're in real mode using 64k segments. Therefore segment |
| * addresses must be multiplied by 16 to obtain their respective linear |
| * addresses. To avoid confusion, linear addresses are written using leading |
| * hex while segment addresses are written as segment:offset. |
| * |
| */ |
| |
| #include <asm/segment.h> |
| #include <generated/utsrelease.h> |
| #include <asm/boot.h> |
| #include <asm/e820.h> |
| #include <asm/page_types.h> |
| #include <asm/setup.h> |
| #include "boot.h" |
| #include "voffset.h" |
| #include "zoffset.h" |
| |
| BOOTSEG = 0x07C0 /* original address of boot-sector */ |
| SYSSEG = 0x1000 /* historical load address >> 4 */ |
| |
| #ifndef SVGA_MODE |
| #define SVGA_MODE ASK_VGA |
| #endif |
| |
| #ifndef RAMDISK |
| #define RAMDISK 0 |
| #endif |
| |
| #ifndef ROOT_RDONLY |
| #define ROOT_RDONLY 1 |
| #endif |
| |
| .code16 |
| .section ".bstext", "ax" |
| |
| .global bootsect_start |
| bootsect_start: |
| #ifdef CONFIG_EFI_STUB |
| # "MZ", MS-DOS header |
| .byte 0x4d |
| .byte 0x5a |
| #endif |
| |
| # Normalize the start address |
| ljmp $BOOTSEG, $start2 |
| |
| start2: |
| movw %cs, %ax |
| movw %ax, %ds |
| movw %ax, %es |
| movw %ax, %ss |
| xorw %sp, %sp |
| sti |
| cld |
| |
| movw $bugger_off_msg, %si |
| |
| msg_loop: |
| lodsb |
| andb %al, %al |
| jz bs_die |
| movb $0xe, %ah |
| movw $7, %bx |
| int $0x10 |
| jmp msg_loop |
| |
| bs_die: |
| # Allow the user to press a key, then reboot |
| xorw %ax, %ax |
| int $0x16 |
| int $0x19 |
| |
| # int 0x19 should never return. In case it does anyway, |
| # invoke the BIOS reset code... |
| ljmp $0xf000,$0xfff0 |
| |
| #ifdef CONFIG_EFI_STUB |
| .org 0x3c |
| # |
| # Offset to the PE header. |
| # |
| .long pe_header |
| #endif /* CONFIG_EFI_STUB */ |
| |
| .section ".bsdata", "a" |
| bugger_off_msg: |
| .ascii "Direct floppy boot is not supported. " |
| .ascii "Use a boot loader program instead.\r\n" |
| .ascii "\n" |
| .ascii "Remove disk and press any key to reboot ...\r\n" |
| .byte 0 |
| |
| #ifdef CONFIG_EFI_STUB |
| pe_header: |
| .ascii "PE" |
| .word 0 |
| |
| coff_header: |
| #ifdef CONFIG_X86_32 |
| .word 0x14c # i386 |
| #else |
| .word 0x8664 # x86-64 |
| #endif |
| .word 3 # nr_sections |
| .long 0 # TimeDateStamp |
| .long 0 # PointerToSymbolTable |
| .long 1 # NumberOfSymbols |
| .word section_table - optional_header # SizeOfOptionalHeader |
| #ifdef CONFIG_X86_32 |
| .word 0x306 # Characteristics. |
| # IMAGE_FILE_32BIT_MACHINE | |
| # IMAGE_FILE_DEBUG_STRIPPED | |
| # IMAGE_FILE_EXECUTABLE_IMAGE | |
| # IMAGE_FILE_LINE_NUMS_STRIPPED |
| #else |
| .word 0x206 # Characteristics |
| # IMAGE_FILE_DEBUG_STRIPPED | |
| # IMAGE_FILE_EXECUTABLE_IMAGE | |
| # IMAGE_FILE_LINE_NUMS_STRIPPED |
| #endif |
| |
| optional_header: |
| #ifdef CONFIG_X86_32 |
| .word 0x10b # PE32 format |
| #else |
| .word 0x20b # PE32+ format |
| #endif |
| .byte 0x02 # MajorLinkerVersion |
| .byte 0x14 # MinorLinkerVersion |
| |
| # Filled in by build.c |
| .long 0 # SizeOfCode |
| |
| .long 0 # SizeOfInitializedData |
| .long 0 # SizeOfUninitializedData |
| |
| # Filled in by build.c |
| .long 0x0000 # AddressOfEntryPoint |
| |
| .long 0x0200 # BaseOfCode |
| #ifdef CONFIG_X86_32 |
| .long 0 # data |
| #endif |
| |
| extra_header_fields: |
| #ifdef CONFIG_X86_32 |
| .long 0 # ImageBase |
| #else |
| .quad 0 # ImageBase |
| #endif |
| .long 0x20 # SectionAlignment |
| .long 0x20 # FileAlignment |
| .word 0 # MajorOperatingSystemVersion |
| .word 0 # MinorOperatingSystemVersion |
| .word 0 # MajorImageVersion |
| .word 0 # MinorImageVersion |
| .word 0 # MajorSubsystemVersion |
| .word 0 # MinorSubsystemVersion |
| .long 0 # Win32VersionValue |
| |
| # |
| # The size of the bzImage is written in tools/build.c |
| # |
| .long 0 # SizeOfImage |
| |
| .long 0x200 # SizeOfHeaders |
| .long 0 # CheckSum |
| .word 0xa # Subsystem (EFI application) |
| .word 0 # DllCharacteristics |
| #ifdef CONFIG_X86_32 |
| .long 0 # SizeOfStackReserve |
| .long 0 # SizeOfStackCommit |
| .long 0 # SizeOfHeapReserve |
| .long 0 # SizeOfHeapCommit |
| #else |
| .quad 0 # SizeOfStackReserve |
| .quad 0 # SizeOfStackCommit |
| .quad 0 # SizeOfHeapReserve |
| .quad 0 # SizeOfHeapCommit |
| #endif |
| .long 0 # LoaderFlags |
| .long 0x6 # NumberOfRvaAndSizes |
| |
| .quad 0 # ExportTable |
| .quad 0 # ImportTable |
| .quad 0 # ResourceTable |
| .quad 0 # ExceptionTable |
| .quad 0 # CertificationTable |
| .quad 0 # BaseRelocationTable |
| |
| # Section table |
| section_table: |
| # |
| # The offset & size fields are filled in by build.c. |
| # |
| .ascii ".setup" |
| .byte 0 |
| .byte 0 |
| .long 0 |
| .long 0x0 # startup_{32,64} |
| .long 0 # Size of initialized data |
| # on disk |
| .long 0x0 # startup_{32,64} |
| .long 0 # PointerToRelocations |
| .long 0 # PointerToLineNumbers |
| .word 0 # NumberOfRelocations |
| .word 0 # NumberOfLineNumbers |
| .long 0x60500020 # Characteristics (section flags) |
| |
| # |
| # The EFI application loader requires a relocation section |
| # because EFI applications must be relocatable. The .reloc |
| # offset & size fields are filled in by build.c. |
| # |
| .ascii ".reloc" |
| .byte 0 |
| .byte 0 |
| .long 0 |
| .long 0 |
| .long 0 # SizeOfRawData |
| .long 0 # PointerToRawData |
| .long 0 # PointerToRelocations |
| .long 0 # PointerToLineNumbers |
| .word 0 # NumberOfRelocations |
| .word 0 # NumberOfLineNumbers |
| .long 0x42100040 # Characteristics (section flags) |
| |
| # |
| # The offset & size fields are filled in by build.c. |
| # |
| .ascii ".text" |
| .byte 0 |
| .byte 0 |
| .byte 0 |
| .long 0 |
| .long 0x0 # startup_{32,64} |
| .long 0 # Size of initialized data |
| # on disk |
| .long 0x0 # startup_{32,64} |
| .long 0 # PointerToRelocations |
| .long 0 # PointerToLineNumbers |
| .word 0 # NumberOfRelocations |
| .word 0 # NumberOfLineNumbers |
| .long 0x60500020 # Characteristics (section flags) |
| |
| #endif /* CONFIG_EFI_STUB */ |
| |
| # Kernel attributes; used by setup. This is part 1 of the |
| # header, from the old boot sector. |
| |
| .section ".header", "a" |
| .globl hdr |
| hdr: |
| setup_sects: .byte 0 /* Filled in by build.c */ |
| root_flags: .word ROOT_RDONLY |
| syssize: .long 0 /* Filled in by build.c */ |
| ram_size: .word 0 /* Obsolete */ |
| vid_mode: .word SVGA_MODE |
| root_dev: .word 0 /* Filled in by build.c */ |
| boot_flag: .word 0xAA55 |
| |
| # offset 512, entry point |
| |
| .globl _start |
| _start: |
| # Explicitly enter this as bytes, or the assembler |
| # tries to generate a 3-byte jump here, which causes |
| # everything else to push off to the wrong offset. |
| .byte 0xeb # short (2-byte) jump |
| .byte start_of_setup-1f |
| 1: |
| |
| # Part 2 of the header, from the old setup.S |
| |
| .ascii "HdrS" # header signature |
| .word 0x020b # header version number (>= 0x0105) |
| # or else old loadlin-1.5 will fail) |
| .globl realmode_swtch |
| realmode_swtch: .word 0, 0 # default_switch, SETUPSEG |
| start_sys_seg: .word SYSSEG # obsolete and meaningless, but just |
| # in case something decided to "use" it |
| .word kernel_version-512 # pointing to kernel version string |
| # above section of header is compatible |
| # with loadlin-1.5 (header v1.5). Don't |
| # change it. |
| |
| type_of_loader: .byte 0 # 0 means ancient bootloader, newer |
| # bootloaders know to change this. |
| # See Documentation/x86/boot.txt for |
| # assigned ids |
| |
| # flags, unused bits must be zero (RFU) bit within loadflags |
| loadflags: |
| LOADED_HIGH = 1 # If set, the kernel is loaded high |
| CAN_USE_HEAP = 0x80 # If set, the loader also has set |
| # heap_end_ptr to tell how much |
| # space behind setup.S can be used for |
| # heap purposes. |
| # Only the loader knows what is free |
| .byte LOADED_HIGH |
| |
| setup_move_size: .word 0x8000 # size to move, when setup is not |
| # loaded at 0x90000. We will move setup |
| # to 0x90000 then just before jumping |
| # into the kernel. However, only the |
| # loader knows how much data behind |
| # us also needs to be loaded. |
| |
| code32_start: # here loaders can put a different |
| # start address for 32-bit code. |
| .long 0x100000 # 0x100000 = default for big kernel |
| |
| ramdisk_image: .long 0 # address of loaded ramdisk image |
| # Here the loader puts the 32-bit |
| # address where it loaded the image. |
| # This only will be read by the kernel. |
| |
| ramdisk_size: .long 0 # its size in bytes |
| |
| bootsect_kludge: |
| .long 0 # obsolete |
| |
| heap_end_ptr: .word _end+STACK_SIZE-512 |
| # (Header version 0x0201 or later) |
| # space from here (exclusive) down to |
| # end of setup code can be used by setup |
| # for local heap purposes. |
| |
| ext_loader_ver: |
| .byte 0 # Extended boot loader version |
| ext_loader_type: |
| .byte 0 # Extended boot loader type |
| |
| cmd_line_ptr: .long 0 # (Header version 0x0202 or later) |
| # If nonzero, a 32-bit pointer |
| # to the kernel command line. |
| # The command line should be |
| # located between the start of |
| # setup and the end of low |
| # memory (0xa0000), or it may |
| # get overwritten before it |
| # gets read. If this field is |
| # used, there is no longer |
| # anything magical about the |
| # 0x90000 segment; the setup |
| # can be located anywhere in |
| # low memory 0x10000 or higher. |
| |
| ramdisk_max: .long 0x7fffffff |
| # (Header version 0x0203 or later) |
| # The highest safe address for |
| # the contents of an initrd |
| # The current kernel allows up to 4 GB, |
| # but leave it at 2 GB to avoid |
| # possible bootloader bugs. |
| |
| kernel_alignment: .long CONFIG_PHYSICAL_ALIGN #physical addr alignment |
| #required for protected mode |
| #kernel |
| #ifdef CONFIG_RELOCATABLE |
| relocatable_kernel: .byte 1 |
| #else |
| relocatable_kernel: .byte 0 |
| #endif |
| min_alignment: .byte MIN_KERNEL_ALIGN_LG2 # minimum alignment |
| pad3: .word 0 |
| |
| cmdline_size: .long COMMAND_LINE_SIZE-1 #length of the command line, |
| #added with boot protocol |
| #version 2.06 |
| |
| hardware_subarch: .long 0 # subarchitecture, added with 2.07 |
| # default to 0 for normal x86 PC |
| |
| hardware_subarch_data: .quad 0 |
| |
| payload_offset: .long ZO_input_data |
| payload_length: .long ZO_z_input_len |
| |
| setup_data: .quad 0 # 64-bit physical pointer to |
| # single linked list of |
| # struct setup_data |
| |
| pref_address: .quad LOAD_PHYSICAL_ADDR # preferred load addr |
| |
| #define ZO_INIT_SIZE (ZO__end - ZO_startup_32 + ZO_z_extract_offset) |
| #define VO_INIT_SIZE (VO__end - VO__text) |
| #if ZO_INIT_SIZE > VO_INIT_SIZE |
| #define INIT_SIZE ZO_INIT_SIZE |
| #else |
| #define INIT_SIZE VO_INIT_SIZE |
| #endif |
| init_size: .long INIT_SIZE # kernel initialization size |
| handover_offset: .long 0x30 # offset to the handover |
| # protocol entry point |
| |
| # End of setup header ##################################################### |
| |
| .section ".entrytext", "ax" |
| start_of_setup: |
| # Force %es = %ds |
| movw %ds, %ax |
| movw %ax, %es |
| cld |
| |
| # Apparently some ancient versions of LILO invoked the kernel with %ss != %ds, |
| # which happened to work by accident for the old code. Recalculate the stack |
| # pointer if %ss is invalid. Otherwise leave it alone, LOADLIN sets up the |
| # stack behind its own code, so we can't blindly put it directly past the heap. |
| |
| movw %ss, %dx |
| cmpw %ax, %dx # %ds == %ss? |
| movw %sp, %dx |
| je 2f # -> assume %sp is reasonably set |
| |
| # Invalid %ss, make up a new stack |
| movw $_end, %dx |
| testb $CAN_USE_HEAP, loadflags |
| jz 1f |
| movw heap_end_ptr, %dx |
| 1: addw $STACK_SIZE, %dx |
| jnc 2f |
| xorw %dx, %dx # Prevent wraparound |
| |
| 2: # Now %dx should point to the end of our stack space |
| andw $~3, %dx # dword align (might as well...) |
| jnz 3f |
| movw $0xfffc, %dx # Make sure we're not zero |
| 3: movw %ax, %ss |
| movzwl %dx, %esp # Clear upper half of %esp |
| sti # Now we should have a working stack |
| |
| # We will have entered with %cs = %ds+0x20, normalize %cs so |
| # it is on par with the other segments. |
| pushw %ds |
| pushw $6f |
| lretw |
| 6: |
| |
| # Check signature at end of setup |
| cmpl $0x5a5aaa55, setup_sig |
| jne setup_bad |
| |
| # Zero the bss |
| movw $__bss_start, %di |
| movw $_end+3, %cx |
| xorl %eax, %eax |
| subw %di, %cx |
| shrw $2, %cx |
| rep; stosl |
| |
| # Jump to C code (should not return) |
| calll main |
| |
| # Setup corrupt somehow... |
| setup_bad: |
| movl $setup_corrupt, %eax |
| calll puts |
| # Fall through... |
| |
| .globl die |
| .type die, @function |
| die: |
| hlt |
| jmp die |
| |
| .size die, .-die |
| |
| .section ".initdata", "a" |
| setup_corrupt: |
| .byte 7 |
| .string "No setup signature found...\n" |
| |
| .data |
| dummy: .long 0 |