lib/relocator
This commit is contained in:
Vladimir 'phcoder' Serbinenko
parent
f84114f583
commit
e7573c5ce2
9 changed files with 509 additions and 120 deletions
148
lib/i386/relocator.c
Normal file
148
lib/i386/relocator.c
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/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 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/mm.h>
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#include <grub/misc.h>
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#include <grub/types.h>
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#include <grub/types.h>
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#include <grub/err.h>
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#include <grub/i386/relocator.h>
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extern grub_uint8_t grub_relocator32_forward_start;
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extern grub_uint8_t grub_relocator32_forward_end;
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extern grub_uint8_t grub_relocator32_backward_start;
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extern grub_uint8_t grub_relocator32_backward_end;
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extern grub_uint32_t grub_relocator32_backward_dest;
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extern grub_uint32_t grub_relocator32_backward_size;
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#ifdef __x86_64__
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extern grub_uint64_t grub_relocator32_backward_src;
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#else
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extern grub_uint32_t grub_relocator32_backward_src;
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#endif
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extern grub_uint32_t grub_relocator32_forward_dest;
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extern grub_uint32_t grub_relocator32_forward_size;
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#ifdef __x86_64__
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extern grub_uint64_t grub_relocator32_forward_src;
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#else
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extern grub_uint32_t grub_relocator32_forward_src;
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#endif
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extern grub_uint32_t grub_relocator32_forward_eax;
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extern grub_uint32_t grub_relocator32_forward_ebx;
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extern grub_uint32_t grub_relocator32_forward_ecx;
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extern grub_uint32_t grub_relocator32_forward_edx;
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extern grub_uint32_t grub_relocator32_forward_eip;
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extern grub_uint32_t grub_relocator32_forward_esp;
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extern grub_uint32_t grub_relocator32_backward_eax;
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extern grub_uint32_t grub_relocator32_backward_ebx;
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extern grub_uint32_t grub_relocator32_backward_ecx;
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extern grub_uint32_t grub_relocator32_backward_edx;
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extern grub_uint32_t grub_relocator32_backward_eip;
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extern grub_uint32_t grub_relocator32_backward_esp;
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#define RELOCATOR_SIZEOF(x) (&grub_relocator32_##x##_end - &grub_relocator32_##x##_start)
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#define RELOCATOR_ALIGN 16
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void *
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grub_relocator32_alloc (grub_size_t size)
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{
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char *playground;
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playground = grub_malloc ((RELOCATOR_SIZEOF(forward) + RELOCATOR_ALIGN)
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+ size
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+ (RELOCATOR_SIZEOF(backward) + RELOCATOR_ALIGN));
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if (! playground)
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return 0;
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*(grub_size_t *) playground = size;
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return playground + RELOCATOR_SIZEOF(forward);
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}
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void
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grub_relocator32_free (void *relocator)
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{
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if (relocator)
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grub_free ((char *) relocator - RELOCATOR_SIZEOF(forward));
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}
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grub_err_t
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grub_relocator32_boot (void *relocator, grub_uint32_t dest,
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struct grub_relocator32_state state)
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{
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grub_size_t size;
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char *playground;
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void (*entry) ();
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playground = (char *) relocator - RELOCATOR_SIZEOF(forward);
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size = *(grub_size_t *) playground;
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if (UINT_TO_PTR (dest) >= relocator)
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{
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int overhead;
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overhead = ALIGN_UP (dest - RELOCATOR_SIZEOF(backward) - RELOCATOR_ALIGN, RELOCATOR_ALIGN);
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grub_relocator32_backward_dest = dest - overhead;
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grub_relocator32_backward_src = PTR_TO_UINT64 (relocator - overhead);
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grub_relocator32_backward_size = size + overhead;
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grub_relocator32_backward_eax = state.eax;
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grub_relocator32_backward_ebx = state.ebx;
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grub_relocator32_backward_ecx = state.ecx;
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grub_relocator32_backward_edx = state.edx;
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grub_relocator32_backward_eip = state.eip;
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grub_relocator32_backward_esp = state.esp;
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grub_memmove (relocator - overhead,
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&grub_relocator32_backward_start,
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RELOCATOR_SIZEOF(backward));
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entry = (void (*) ()) (relocator - overhead);
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}
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else
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{
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int overhead;
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overhead = ALIGN_UP (dest + size, RELOCATOR_ALIGN)
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+ RELOCATOR_SIZEOF(forward) - (dest + size);
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grub_relocator32_forward_dest = dest;
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grub_relocator32_forward_src = PTR_TO_UINT64 (relocator);
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grub_relocator32_forward_size = size + overhead;
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grub_relocator32_forward_eax = state.eax;
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grub_relocator32_forward_ebx = state.ebx;
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grub_relocator32_forward_ecx = state.ecx;
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grub_relocator32_forward_edx = state.edx;
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grub_relocator32_forward_eip = state.eip;
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grub_relocator32_forward_esp = state.esp;
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grub_memmove (relocator + size + overhead - RELOCATOR_SIZEOF(forward),
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&grub_relocator32_forward_start, RELOCATOR_SIZEOF(forward));
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entry = (void (*) ()) (relocator + size + overhead - RELOCATOR_SIZEOF(forward));
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}
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entry ();
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/* Not reached. */
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return GRUB_ERR_NONE;
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}
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269
lib/i386/relocator_asm.S
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269
lib/i386/relocator_asm.S
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/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 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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#ifdef BACKWARD
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#define RELOCATOR_VARIABLE(x) VARIABLE(grub_relocator32_backward_ ## x)
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#else
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#define RELOCATOR_VARIABLE(x) VARIABLE(grub_relocator32_forward_ ## x)
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#endif
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.p2align 4 /* force 16-byte alignment */
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RELOCATOR_VARIABLE(start)
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#ifdef BACKWARD
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base:
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#endif
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cli
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#ifndef __x86_64__
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/* mov imm32, %eax */
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.byte 0xb8
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RELOCATOR_VARIABLE(dest)
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.long 0
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mov %eax, %edi
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/* mov imm32, %eax */
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.byte 0xb8
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RELOCATOR_VARIABLE(src)
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.long 0
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mov %eax, %esi
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/* mov imm32, %ecx */
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.byte 0xb9
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RELOCATOR_VARIABLE(size)
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.long 0
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mov %edi, %eax
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#ifndef BACKWARD
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add %ecx, %eax
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#endif
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add $0x3, %ecx
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shr $2, %ecx
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#ifdef BACKWARD
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/* Backward movsl is implicitly off-by-four. compensate that. */
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subl $4, %esi
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subl $4, %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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movsl
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#else
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/* Forward copy. */
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cld
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rep
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movsl
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#endif
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/* %eax contains now our new base. */
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mov %eax, %esi
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add $(cont0 - base), %eax
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jmp *%eax
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cont0:
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#else
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xorq %rax, %rax
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/* mov imm32, %eax */
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.byte 0xb8
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RELOCATOR_VARIABLE(dest)
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.long 0
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mov %eax, %edi
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/* mov imm64, %rax */
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.byte 0xb8
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RELOCATOR_VARIABLE(src)
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.long 0, 0
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mov %rax, %rsi
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xorl %rcx, %rcx
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/* mov imm32, %ecx */
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.byte 0xb9
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RELOCATOR_VARIABLE(size)
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.long 0
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mov %rdi, %rax
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#ifndef BACKWARD
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add %rcx, %rax
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#endif
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add $0x3, %rcx
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shr $2, %rcx
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#ifdef BACKWARD
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/* Backward movsl is implicitly off-by-four. compensate that. */
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subl $4, %rsi
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subl $4, %rdi
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/* Backward copy. */
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std
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addl %rcx, %rsi
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addl %rcx, %rdi
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rep
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movsl
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#else
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/* Forward copy. */
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cld
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rep
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movsl
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#endif
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/* %rax contains now our new 'base'. */
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mov %rax, %rsi
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#ifdef APPLE_CC
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add $(cont0 - base), %eax
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#else
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add $(cont0 - base), %rax
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#endif
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jmp *%rax
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cont0:
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#ifdef APPLE_CC
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lea (cont1 - base) (%esi, 1), %eax
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mov %eax, (jump_vector - base) (%esi, 1)
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lea (gdt - base) (%esi, 1), %eax
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mov %eax, (gdt_addr - base) (%esi, 1)
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/* Switch to compatibility mode. */
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lgdt (gdtdesc - base) (%esi, 1)
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/* Update %cs. Thanks to David Miller for pointing this mistake out. */
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ljmp *(jump_vector - base) (%esi,1)
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#else
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lea (cont1 - base) (%rsi, 1), %rax
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mov %eax, (jump_vector - base) (%rsi, 1)
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lea (gdt - base) (%rsi, 1), %rax
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mov %rax, (gdt_addr - base) (%rsi, 1)
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/* Switch to compatibility mode. */
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lgdt (gdtdesc - base) (%rsi, 1)
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/* Update %cs. Thanks to David Miller for pointing this mistake out. */
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ljmp *(jump_vector - base) (%rsi, 1)
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#endif
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cont1:
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.code32
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/* Update other registers. */
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mov $0x18, %eax
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mov %eax, %ds
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mov %eax, %es
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mov %eax, %fs
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mov %eax, %gs
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mov %eax, %ss
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/* Disable paging. */
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mov %cr0, %eax
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and $0x7fffffff, %eax
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mov %eax, %cr0
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/* Disable amd64. */
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mov $0xc0000080, %ecx
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rdmsr
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and $0xfffffeff, %eax
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wrmsr
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/* Turn off PAE. */
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movl %cr4, %eax
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and $0xffffffcf, %eax
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mov %eax, %cr4
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jmp cont2
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cont2:
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#endif
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.code32
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/* mov imm32, %eax */
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.byte 0xb8
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RELOCATOR_VARIABLE (esp)
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.long 0
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movl %eax, %esp
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/* mov imm32, %eax */
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.byte 0xb8
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RELOCATOR_VARIABLE (eax)
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.long 0
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/* mov imm32, %ebx */
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.byte 0xbb
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RELOCATOR_VARIABLE (ebx)
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.long 0
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/* mov imm32, %ecx */
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.byte 0xb9
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RELOCATOR_VARIABLE (ecx)
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.long 0
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/* mov imm32, %edx */
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.byte 0xba
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RELOCATOR_VARIABLE (edx)
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.long 0
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/* Cleared direction flag is of no problem with any current
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payload and makes this implementation easier. */
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cld
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.byte 0xea
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RELOCATOR_VARIABLE (eip)
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.long 0
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.word 0x08
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#ifdef __x86_64__
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/* GDT. Copied from loader/i386/linux.c. */
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.p2align 4
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gdt:
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/* NULL. */
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.byte 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
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/* Reserved. */
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.byte 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
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/* Code segment. */
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.byte 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x9A, 0xCF, 0x00
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/* Data segment. */
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.byte 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x92, 0xCF, 0x00
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gdtdesc:
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.word 31
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gdt_addr:
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/* Filled by the code. */
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.quad 0
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.p2align 4
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jump_vector:
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/* Jump location. Is filled by the code */
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.long 0
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.long 0x10
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#endif
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#ifndef BACKWARD
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base:
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#endif
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RELOCATOR_VARIABLE(end)
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2
lib/i386/relocator_backward.S
Normal file
2
lib/i386/relocator_backward.S
Normal file
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@ -0,0 +1,2 @@
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#define BACKWARD
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#include "relocator_asm.S"
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