217 lines
4.6 KiB
ArmAsm
217 lines
4.6 KiB
ArmAsm
/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 1999,2000,2001,2002,2003,2005,2006,2007,2008,2009,2011 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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/*
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* Note: These functions defined in this file may be called from C.
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* Be careful of that you must not modify some registers. Quote
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* from gcc-2.95.2/gcc/config/i386/i386.h:
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1 for registers not available across function calls.
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These must include the FIXED_REGISTERS and also any
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registers that can be used without being saved.
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The latter must include the registers where values are returned
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and the register where structure-value addresses are passed.
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Aside from that, you can include as many other registers as you like.
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ax,dx,cx,bx,si,di,bp,sp,st,st1,st2,st3,st4,st5,st6,st7,arg
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{ 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 }
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*/
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/*
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* Note: GRUB is compiled with the options -mrtd and -mregparm=3.
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* So the first three arguments are passed in %eax, %edx, and %ecx,
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* respectively, and if a function has a fixed number of arguments
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* and the number is greater than three, the function must return
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* with "ret $N" where N is ((the number of arguments) - 3) * 4.
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*/
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#include <config.h>
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#include <grub/symbol.h>
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#include <multiboot.h>
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#ifdef __APPLE__
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#include <grub/i386/pc/memory.h>
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#endif
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.file "startup.S"
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.text
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.globl start, _start, __start
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start:
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_start:
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__start:
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#ifdef __APPLE__
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LOCAL(start):
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#endif
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.code32
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movl %ecx, (LOCAL(real_to_prot_addr) - _start) (%esi)
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movl %edi, (LOCAL(prot_to_real_addr) - _start) (%esi)
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movl %eax, (EXT_C(grub_realidt) - _start) (%esi)
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/* copy back the decompressed part (except the modules) */
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#ifdef __APPLE__
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movl $EXT_C(_edata), %ecx
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subl $LOCAL(start), %ecx
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#else
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movl $(_edata - _start), %ecx
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#endif
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movl $(_start), %edi
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rep
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movsb
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movl $LOCAL (cont), %esi
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jmp *%esi
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LOCAL(cont):
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#if 0
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/* copy modules before cleaning out the bss */
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movl EXT_C(grub_total_module_size), %ecx
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movl EXT_C(grub_kernel_image_size), %esi
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addl %ecx, %esi
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addl $_start, %esi
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decl %esi
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movl $END_SYMBOL, %edi
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addl %ecx, %edi
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decl %edi
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std
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rep
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movsb
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#endif
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#ifdef __APPLE__
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/* clean out the bss */
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movl $EXT_C(_edata), %edi
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/* compute the bss length */
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movl $GRUB_MEMORY_MACHINE_SCRATCH_ADDR, %ecx
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#else
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/* clean out the bss */
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movl $BSS_START_SYMBOL, %edi
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/* compute the bss length */
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movl $END_SYMBOL, %ecx
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#endif
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subl %edi, %ecx
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/* clean out */
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xorl %eax, %eax
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cld
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rep
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stosb
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movl %edx, EXT_C(grub_boot_device)
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/*
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* Call the start of main body of C code.
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*/
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call EXT_C(grub_main)
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LOCAL(real_to_prot_addr):
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.long 0
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LOCAL(prot_to_real_addr):
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.long 0
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.macro PROT_TO_REAL
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movl LOCAL(prot_to_real_addr), %eax
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call *%eax
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.endm
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.macro REAL_TO_PROT
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movl LOCAL(real_to_prot_addr), %eax
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DATA32 call *%ax
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.endm
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/*
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* grub_exit()
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*
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* Exit the system.
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*/
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FUNCTION(grub_exit)
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PROT_TO_REAL
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.code16
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/* Tell the BIOS a boot failure. If this does not work, reboot. */
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int $0x18
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/* set 0x472 to 0x0000 for cold boot (0x1234 for warm boot) */
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xorw %ax, %ax
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movw $0x0472, %di
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movw %ax, (%di)
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ljmp $0xf000, $0xfff0
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.code32
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/*
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* int grub_pxe_call (int func, void* data, grub_uint32_t pxe_rm_entry);
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*/
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FUNCTION(grub_pxe_call)
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pushl %ebp
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movl %esp, %ebp
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pushl %esi
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pushl %edi
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pushl %ebx
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movl %ecx, %ebx
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movl %eax, %ecx
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movl %edx, %eax
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andl $0xF, %eax
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shrl $4, %edx
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shll $16, %edx
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addl %eax, %edx
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PROT_TO_REAL
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.code16
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pushl %ebx
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pushl %edx
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pushw %cx
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movw %sp, %bx
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lcall *%ss:6(%bx)
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cld
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addw $10, %sp
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movw %ax, %cx
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REAL_TO_PROT
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.code32
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movzwl %cx, %eax
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popl %ebx
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popl %edi
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popl %esi
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popl %ebp
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ret
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#include "../int.S"
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VARIABLE(grub_realidt)
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.long 0
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#ifdef __APPLE__
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/* Older versions of objconv assume that there is the same number
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of text and data sections. Hence this dummy. */
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.section __TEXT, __zz_dummy
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.byte 0
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.globl EXT_C(_edata)
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.globl EXT_C(grub_boot_device)
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.zerofill __DATA, __aa_before_bss, EXT_C(_edata), 1, 0
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.zerofill __DATA, __bss, EXT_C(grub_boot_device), 4, 2
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#else
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.bss
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VARIABLE(grub_boot_device)
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.long 0
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#endif
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