mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-25 05:34:00 +08:00
291f36325f
There is currently a large divide between kernel development and the
development of EFI boot loaders. The idea behind this patch is to give
the kernel developers full control over the EFI boot process. As
H. Peter Anvin put it,
"The 'kernel carries its own stub' approach been very successful in
dealing with BIOS, and would make a lot of sense to me for EFI as
well."
This patch introduces an EFI boot stub that allows an x86 bzImage to
be loaded and executed by EFI firmware. The bzImage appears to the
firmware as an EFI application. Luckily there are enough free bits
within the bzImage header so that it can masquerade as an EFI
application, thereby coercing the EFI firmware into loading it and
jumping to its entry point. The beauty of this masquerading approach
is that both BIOS and EFI boot loaders can still load and run the same
bzImage, thereby allowing a single kernel image to work in any boot
environment.
The EFI boot stub supports multiple initrds, but they must exist on
the same partition as the bzImage. Command-line arguments for the
kernel can be appended after the bzImage name when run from the EFI
shell, e.g.
Shell> bzImage console=ttyS0 root=/dev/sdb initrd=initrd.img
v7:
- Fix checkpatch warnings.
v6:
- Try to allocate initrd memory just below hdr->inird_addr_max.
v5:
- load_options_size is UTF-16, which needs dividing by 2 to convert
to the corresponding ASCII size.
v4:
- Don't read more than image->load_options_size
v3:
- Fix following warnings when compiling CONFIG_EFI_STUB=n
arch/x86/boot/tools/build.c: In function ‘main’:
arch/x86/boot/tools/build.c:138:24: warning: unused variable ‘pe_header’
arch/x86/boot/tools/build.c:138:15: warning: unused variable ‘file_sz’
- As reported by Matthew Garrett, some Apple machines have GOPs that
don't have hardware attached. We need to weed these out by
searching for ones that handle the PCIIO protocol.
- Don't allocate memory if no initrds are on cmdline
- Don't trust image->load_options_size
Maarten Lankhorst noted:
- Don't strip first argument when booted from efibootmgr
- Don't allocate too much memory for cmdline
- Don't update cmdline_size, the kernel considers it read-only
- Don't accept '\n' for initrd names
v2:
- File alignment was too large, was 8192 should be 512. Reported by
Maarten Lankhorst on LKML.
- Added UGA support for graphics
- Use VIDEO_TYPE_EFI instead of hard-coded number.
- Move linelength assignment until after we've assigned depth
- Dynamically fill out AddressOfEntryPoint in tools/build.c
- Don't use magic number for GDT/TSS stuff. Requested by Andi Kleen
- The bzImage may need to be relocated as it may have been loaded at
a high address address by the firmware. This was required to get my
macbook booting because the firmware loaded it at 0x7cxxxxxx, which
triggers this error in decompress_kernel(),
if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff))
error("Destination address too large");
Cc: Mike Waychison <mikew@google.com>
Cc: Matthew Garrett <mjg@redhat.com>
Tested-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/1321383097.2657.9.camel@mfleming-mobl1.ger.corp.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
479 lines
12 KiB
ArmAsm
479 lines
12 KiB
ArmAsm
/*
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* header.S
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* Based on bootsect.S and setup.S
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* modified by more people than can be counted
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*
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* Rewritten as a common file by H. Peter Anvin (Apr 2007)
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*
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* BIG FAT NOTE: We're in real mode using 64k segments. Therefore segment
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* addresses must be multiplied by 16 to obtain their respective linear
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* addresses. To avoid confusion, linear addresses are written using leading
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* hex while segment addresses are written as segment:offset.
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*
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*/
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#include <asm/segment.h>
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#include <generated/utsrelease.h>
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#include <asm/boot.h>
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#include <asm/e820.h>
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#include <asm/page_types.h>
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#include <asm/setup.h>
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#include "boot.h"
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#include "voffset.h"
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#include "zoffset.h"
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BOOTSEG = 0x07C0 /* original address of boot-sector */
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SYSSEG = 0x1000 /* historical load address >> 4 */
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#ifndef SVGA_MODE
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#define SVGA_MODE ASK_VGA
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#endif
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#ifndef RAMDISK
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#define RAMDISK 0
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#endif
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#ifndef ROOT_RDONLY
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#define ROOT_RDONLY 1
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#endif
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.code16
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.section ".bstext", "ax"
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.global bootsect_start
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bootsect_start:
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#ifdef CONFIG_EFI_STUB
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# "MZ", MS-DOS header
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.byte 0x4d
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.byte 0x5a
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#endif
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# Normalize the start address
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ljmp $BOOTSEG, $start2
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start2:
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movw %cs, %ax
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movw %ax, %ds
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movw %ax, %es
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movw %ax, %ss
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xorw %sp, %sp
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sti
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cld
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movw $bugger_off_msg, %si
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msg_loop:
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lodsb
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andb %al, %al
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jz bs_die
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movb $0xe, %ah
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movw $7, %bx
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int $0x10
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jmp msg_loop
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bs_die:
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# Allow the user to press a key, then reboot
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xorw %ax, %ax
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int $0x16
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int $0x19
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# int 0x19 should never return. In case it does anyway,
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# invoke the BIOS reset code...
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ljmp $0xf000,$0xfff0
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#ifdef CONFIG_EFI_STUB
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.org 0x3c
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#
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# Offset to the PE header.
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#
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.long pe_header
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#endif /* CONFIG_EFI_STUB */
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.section ".bsdata", "a"
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bugger_off_msg:
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.ascii "Direct booting from floppy is no longer supported.\r\n"
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.ascii "Please use a boot loader program instead.\r\n"
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.ascii "\n"
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.ascii "Remove disk and press any key to reboot . . .\r\n"
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.byte 0
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#ifdef CONFIG_EFI_STUB
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pe_header:
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.ascii "PE"
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.word 0
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coff_header:
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#ifdef CONFIG_X86_32
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.word 0x14c # i386
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#else
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.word 0x8664 # x86-64
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#endif
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.word 2 # nr_sections
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.long 0 # TimeDateStamp
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.long 0 # PointerToSymbolTable
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.long 1 # NumberOfSymbols
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.word section_table - optional_header # SizeOfOptionalHeader
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#ifdef CONFIG_X86_32
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.word 0x306 # Characteristics.
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# IMAGE_FILE_32BIT_MACHINE |
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# IMAGE_FILE_DEBUG_STRIPPED |
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# IMAGE_FILE_EXECUTABLE_IMAGE |
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# IMAGE_FILE_LINE_NUMS_STRIPPED
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#else
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.word 0x206 # Characteristics
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# IMAGE_FILE_DEBUG_STRIPPED |
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# IMAGE_FILE_EXECUTABLE_IMAGE |
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# IMAGE_FILE_LINE_NUMS_STRIPPED
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#endif
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optional_header:
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#ifdef CONFIG_X86_32
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.word 0x10b # PE32 format
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#else
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.word 0x20b # PE32+ format
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#endif
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.byte 0x02 # MajorLinkerVersion
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.byte 0x14 # MinorLinkerVersion
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# Filled in by build.c
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.long 0 # SizeOfCode
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.long 0 # SizeOfInitializedData
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.long 0 # SizeOfUninitializedData
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# Filled in by build.c
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.long 0x0000 # AddressOfEntryPoint
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.long 0x0000 # BaseOfCode
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#ifdef CONFIG_X86_32
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.long 0 # data
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#endif
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extra_header_fields:
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#ifdef CONFIG_X86_32
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.long 0 # ImageBase
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#else
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.quad 0 # ImageBase
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#endif
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.long 0x1000 # SectionAlignment
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.long 0x200 # FileAlignment
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.word 0 # MajorOperatingSystemVersion
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.word 0 # MinorOperatingSystemVersion
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.word 0 # MajorImageVersion
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.word 0 # MinorImageVersion
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.word 0 # MajorSubsystemVersion
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.word 0 # MinorSubsystemVersion
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.long 0 # Win32VersionValue
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#
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# The size of the bzImage is written in tools/build.c
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#
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.long 0 # SizeOfImage
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.long 0x200 # SizeOfHeaders
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.long 0 # CheckSum
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.word 0xa # Subsystem (EFI application)
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.word 0 # DllCharacteristics
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#ifdef CONFIG_X86_32
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.long 0 # SizeOfStackReserve
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.long 0 # SizeOfStackCommit
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.long 0 # SizeOfHeapReserve
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.long 0 # SizeOfHeapCommit
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#else
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.quad 0 # SizeOfStackReserve
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.quad 0 # SizeOfStackCommit
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.quad 0 # SizeOfHeapReserve
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.quad 0 # SizeOfHeapCommit
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#endif
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.long 0 # LoaderFlags
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.long 0x1 # NumberOfRvaAndSizes
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.quad 0 # ExportTable
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.quad 0 # ImportTable
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.quad 0 # ResourceTable
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.quad 0 # ExceptionTable
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.quad 0 # CertificationTable
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.quad 0 # BaseRelocationTable
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# Section table
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section_table:
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.ascii ".text"
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.byte 0
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.byte 0
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.byte 0
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.long 0
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.long 0x0 # startup_{32,64}
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.long 0 # Size of initialized data
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# on disk
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.long 0x0 # startup_{32,64}
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.long 0 # PointerToRelocations
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.long 0 # PointerToLineNumbers
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.word 0 # NumberOfRelocations
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.word 0 # NumberOfLineNumbers
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.long 0x60500020 # Characteristics (section flags)
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#
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# The EFI application loader requires a relocation section
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# because EFI applications are relocatable and not having
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# this section seems to confuse it. But since we don't need
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# the loader to fixup any relocs for us just fill it with a
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# single dummy reloc.
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#
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.ascii ".reloc"
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.byte 0
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.byte 0
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.long reloc_end - reloc_start
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.long reloc_start
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.long reloc_end - reloc_start # SizeOfRawData
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.long reloc_start # PointerToRawData
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.long 0 # PointerToRelocations
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.long 0 # PointerToLineNumbers
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.word 0 # NumberOfRelocations
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.word 0 # NumberOfLineNumbers
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.long 0x42100040 # Characteristics (section flags)
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#endif /* CONFIG_EFI_STUB */
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# Kernel attributes; used by setup. This is part 1 of the
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# header, from the old boot sector.
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.section ".header", "a"
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.globl hdr
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hdr:
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setup_sects: .byte 0 /* Filled in by build.c */
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root_flags: .word ROOT_RDONLY
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syssize: .long 0 /* Filled in by build.c */
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ram_size: .word 0 /* Obsolete */
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vid_mode: .word SVGA_MODE
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root_dev: .word 0 /* Filled in by build.c */
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boot_flag: .word 0xAA55
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# offset 512, entry point
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.globl _start
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_start:
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# Explicitly enter this as bytes, or the assembler
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# tries to generate a 3-byte jump here, which causes
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# everything else to push off to the wrong offset.
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.byte 0xeb # short (2-byte) jump
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.byte start_of_setup-1f
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1:
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# Part 2 of the header, from the old setup.S
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.ascii "HdrS" # header signature
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.word 0x020a # header version number (>= 0x0105)
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# or else old loadlin-1.5 will fail)
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.globl realmode_swtch
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realmode_swtch: .word 0, 0 # default_switch, SETUPSEG
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start_sys_seg: .word SYSSEG # obsolete and meaningless, but just
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# in case something decided to "use" it
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.word kernel_version-512 # pointing to kernel version string
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# above section of header is compatible
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# with loadlin-1.5 (header v1.5). Don't
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# change it.
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type_of_loader: .byte 0 # 0 means ancient bootloader, newer
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# bootloaders know to change this.
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# See Documentation/x86/boot.txt for
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# assigned ids
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# flags, unused bits must be zero (RFU) bit within loadflags
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loadflags:
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LOADED_HIGH = 1 # If set, the kernel is loaded high
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CAN_USE_HEAP = 0x80 # If set, the loader also has set
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# heap_end_ptr to tell how much
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# space behind setup.S can be used for
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# heap purposes.
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# Only the loader knows what is free
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.byte LOADED_HIGH
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setup_move_size: .word 0x8000 # size to move, when setup is not
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# loaded at 0x90000. We will move setup
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# to 0x90000 then just before jumping
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# into the kernel. However, only the
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# loader knows how much data behind
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# us also needs to be loaded.
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code32_start: # here loaders can put a different
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# start address for 32-bit code.
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.long 0x100000 # 0x100000 = default for big kernel
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ramdisk_image: .long 0 # address of loaded ramdisk image
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# Here the loader puts the 32-bit
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# address where it loaded the image.
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# This only will be read by the kernel.
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ramdisk_size: .long 0 # its size in bytes
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bootsect_kludge:
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.long 0 # obsolete
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heap_end_ptr: .word _end+STACK_SIZE-512
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# (Header version 0x0201 or later)
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# space from here (exclusive) down to
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# end of setup code can be used by setup
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# for local heap purposes.
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ext_loader_ver:
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.byte 0 # Extended boot loader version
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ext_loader_type:
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.byte 0 # Extended boot loader type
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cmd_line_ptr: .long 0 # (Header version 0x0202 or later)
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# If nonzero, a 32-bit pointer
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# to the kernel command line.
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# The command line should be
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# located between the start of
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# setup and the end of low
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# memory (0xa0000), or it may
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# get overwritten before it
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# gets read. If this field is
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# used, there is no longer
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# anything magical about the
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# 0x90000 segment; the setup
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# can be located anywhere in
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# low memory 0x10000 or higher.
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ramdisk_max: .long 0x7fffffff
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# (Header version 0x0203 or later)
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# The highest safe address for
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# the contents of an initrd
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# The current kernel allows up to 4 GB,
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# but leave it at 2 GB to avoid
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# possible bootloader bugs.
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kernel_alignment: .long CONFIG_PHYSICAL_ALIGN #physical addr alignment
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#required for protected mode
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#kernel
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#ifdef CONFIG_RELOCATABLE
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relocatable_kernel: .byte 1
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#else
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relocatable_kernel: .byte 0
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#endif
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min_alignment: .byte MIN_KERNEL_ALIGN_LG2 # minimum alignment
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pad3: .word 0
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cmdline_size: .long COMMAND_LINE_SIZE-1 #length of the command line,
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#added with boot protocol
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#version 2.06
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hardware_subarch: .long 0 # subarchitecture, added with 2.07
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# default to 0 for normal x86 PC
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hardware_subarch_data: .quad 0
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payload_offset: .long ZO_input_data
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payload_length: .long ZO_z_input_len
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setup_data: .quad 0 # 64-bit physical pointer to
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# single linked list of
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# struct setup_data
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pref_address: .quad LOAD_PHYSICAL_ADDR # preferred load addr
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#define ZO_INIT_SIZE (ZO__end - ZO_startup_32 + ZO_z_extract_offset)
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#define VO_INIT_SIZE (VO__end - VO__text)
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#if ZO_INIT_SIZE > VO_INIT_SIZE
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#define INIT_SIZE ZO_INIT_SIZE
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#else
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#define INIT_SIZE VO_INIT_SIZE
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#endif
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init_size: .long INIT_SIZE # kernel initialization size
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# End of setup header #####################################################
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.section ".entrytext", "ax"
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start_of_setup:
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#ifdef SAFE_RESET_DISK_CONTROLLER
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# Reset the disk controller.
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movw $0x0000, %ax # Reset disk controller
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movb $0x80, %dl # All disks
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int $0x13
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#endif
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# Force %es = %ds
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movw %ds, %ax
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movw %ax, %es
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cld
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# Apparently some ancient versions of LILO invoked the kernel with %ss != %ds,
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# which happened to work by accident for the old code. Recalculate the stack
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# pointer if %ss is invalid. Otherwise leave it alone, LOADLIN sets up the
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# stack behind its own code, so we can't blindly put it directly past the heap.
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movw %ss, %dx
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cmpw %ax, %dx # %ds == %ss?
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movw %sp, %dx
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je 2f # -> assume %sp is reasonably set
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# Invalid %ss, make up a new stack
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movw $_end, %dx
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testb $CAN_USE_HEAP, loadflags
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jz 1f
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movw heap_end_ptr, %dx
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1: addw $STACK_SIZE, %dx
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jnc 2f
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xorw %dx, %dx # Prevent wraparound
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2: # Now %dx should point to the end of our stack space
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andw $~3, %dx # dword align (might as well...)
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jnz 3f
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movw $0xfffc, %dx # Make sure we're not zero
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3: movw %ax, %ss
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movzwl %dx, %esp # Clear upper half of %esp
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sti # Now we should have a working stack
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# We will have entered with %cs = %ds+0x20, normalize %cs so
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# it is on par with the other segments.
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pushw %ds
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pushw $6f
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lretw
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6:
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# Check signature at end of setup
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cmpl $0x5a5aaa55, setup_sig
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jne setup_bad
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# Zero the bss
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movw $__bss_start, %di
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movw $_end+3, %cx
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xorl %eax, %eax
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subw %di, %cx
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shrw $2, %cx
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rep; stosl
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# Jump to C code (should not return)
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calll main
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# Setup corrupt somehow...
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setup_bad:
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movl $setup_corrupt, %eax
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calll puts
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# Fall through...
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.globl die
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.type die, @function
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die:
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hlt
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jmp die
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.size die, .-die
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.section ".initdata", "a"
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setup_corrupt:
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.byte 7
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.string "No setup signature found...\n"
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.data
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dummy: .long 0
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.section .reloc
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reloc_start:
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.long dummy - reloc_start
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.long 10
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.word 0
|
|
reloc_end:
|