3bb7abcfbf
* loader/i386/multiboot_helper.S (grub_multiboot_backward_relocator): Clear direction flag before jumping to OS. (grub_multiboot2_real_boot): Likewise.
118 lines
3 KiB
ArmAsm
118 lines
3 KiB
ArmAsm
/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 1999,2000,2001,2002,2003,2005,2006,2007,2008,2009 Free Software Foundation, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <grub/symbol.h>
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#include <multiboot.h>
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#include <multiboot2.h>
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.p2align 2 /* force 4-byte alignment */
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/*
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* This starts the multiboot kernel.
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*/
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VARIABLE(grub_multiboot_payload_size)
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.long 0
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VARIABLE(grub_multiboot_payload_orig)
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.long 0
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VARIABLE(grub_multiboot_payload_dest)
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.long 0
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VARIABLE(grub_multiboot_payload_entry_offset)
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.long 0
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/*
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* The relocators below understand the following parameters:
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* ecx: Size of the block to be copied.
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* esi: Where to copy from (always lowest address, even if we're relocating
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* backwards).
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* edi: Where to copy to (likewise).
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* edx: Offset of the entry point (relative to the beginning of the block).
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*/
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VARIABLE(grub_multiboot_forward_relocator)
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/* Add entry offset. */
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addl %edi, %edx
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/* Forward copy. */
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cld
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rep
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movsb
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jmp *%edx
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VARIABLE(grub_multiboot_forward_relocator_end)
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VARIABLE(grub_multiboot_backward_relocator)
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/* Add entry offset (before %edi is mangled). */
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addl %edi, %edx
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/* Backward movsb is implicitly off-by-one. compensate that. */
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decl %esi
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decl %edi
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/* Backward copy. */
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std
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addl %ecx, %esi
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addl %ecx, %edi
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rep
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movsb
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cld
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jmp *%edx
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VARIABLE(grub_multiboot_backward_relocator_end)
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FUNCTION(grub_multiboot_real_boot)
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/* Push the entry address on the stack. */
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pushl %eax
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/* Move the address of the multiboot information structure to ebx. */
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movl %edx,%ebx
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/* Interrupts should be disabled. */
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cli
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/* Where do we copy what from. */
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movl EXT_C(grub_multiboot_payload_size), %ecx
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movl EXT_C(grub_multiboot_payload_orig), %esi
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movl EXT_C(grub_multiboot_payload_dest), %edi
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movl EXT_C(grub_multiboot_payload_entry_offset), %edx
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/* Move the magic value into eax. */
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movl $MULTIBOOT_MAGIC2, %eax
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/* Jump to the relocator. */
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popl %ebp
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jmp *%ebp
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/*
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* This starts the multiboot 2 kernel.
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*/
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FUNCTION(grub_multiboot2_real_boot)
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/* Push the entry address on the stack. */
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pushl %eax
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/* Move the address of the multiboot information structure to ebx. */
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movl %edx,%ebx
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/* Interrupts should be disabled. */
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cli
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/* Move the magic value into eax and jump to the kernel. */
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movl $MULTIBOOT2_BOOTLOADER_MAGIC,%eax
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popl %ecx
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cld
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jmp *%ecx
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