On Mon, Aug 3, 2009 at 2:06 PM, Vladimir 'phcoder' Serbinenko<phco...@gmail.com> wrote: > Hello. As discussed on IRC it would be preferable if all loaders use > flexible technics for loading kernels using relocators as currently > multiboot and xnu does. Here is a relocator framework based on > multiboot and xnu relocator. As an advantage it switches from x86-64 > to i386 if necessary. With it and some more patches I was able to load > mbtest on qemu64 with tianocore Small update: new function for increasing relocatable space Can someone test it with situations requiring backward allocator? (dest > src) A problem which is perhaps currently present is if abs(desc-src) < RELOCATOR_SIZE then relocator may overwrite itself and fail. A possible solution is to allocate a bit more space in relocatable buffer to be able to change src by at most RELOCATOR_SIZE - this will be enough to set dest=src in these situations and use a "null" relocator (to be implemented)
> > -- > Regards > Vladimir 'phcoder' Serbinenko > > Personal git repository: http://repo.or.cz/w/grub2/phcoder.git > -- Regards Vladimir 'phcoder' Serbinenko Personal git repository: http://repo.or.cz/w/grub2/phcoder.git
diff --git a/conf/i386.rmk b/conf/i386.rmk index 93f84ce..33d49b5 100644 --- a/conf/i386.rmk +++ b/conf/i386.rmk @@ -14,3 +14,9 @@ pkglib_MODULES += vga_text.mod vga_text_mod_SOURCES = term/i386/pc/vga_text.c term/i386/vga_common.c vga_text_mod_CFLAGS = $(COMMON_CFLAGS) vga_text_mod_LDFLAGS = $(COMMON_LDFLAGS) + +pkglib_MODULES += relocator.mod +relocator_mod_SOURCES = lib/i386/relocator.c lib/i386/relocator_asm.S lib/i386/relocator_backward.S +relocator_mod_CFLAGS = $(COMMON_CFLAGS) +relocator_mod_ASFLAGS = $(COMMON_ASFLAGS) +relocator_mod_LDFLAGS = $(COMMON_LDFLAGS) diff --git a/include/grub/i386/relocator.h b/include/grub/i386/relocator.h new file mode 100644 index 0000000..ef7fe23 --- /dev/null +++ b/include/grub/i386/relocator.h @@ -0,0 +1,41 @@ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2009 Free Software Foundation, Inc. + * + * GRUB is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * GRUB is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GRUB. If not, see <http://www.gnu.org/licenses/>. + */ + +#ifndef GRUB_RELOCATOR_CPU_HEADER +#define GRUB_RELOCATOR_CPU_HEADER 1 + +#include <grub/types.h> +#include <grub/err.h> + +struct grub_relocator32_state +{ + grub_uint32_t esp; + grub_uint32_t eax; + grub_uint32_t ebx; + grub_uint32_t ecx; + grub_uint32_t edx; + grub_uint32_t eip; +}; + +void *grub_relocator32_alloc (grub_size_t size); +grub_err_t grub_relocator32_boot (void *relocator, grub_uint32_t dest, + struct grub_relocator32_state state); +void *grub_relocator32_realloc (void *relocator, grub_size_t size); +void grub_relocator32_free (void *relocator); + +#endif /* ! GRUB_RELOCATOR_CPU_HEADER */ diff --git a/lib/i386/relocator.c b/lib/i386/relocator.c new file mode 100644 index 0000000..0205d8e --- /dev/null +++ b/lib/i386/relocator.c @@ -0,0 +1,173 @@ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2009 Free Software Foundation, Inc. + * + * GRUB is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * GRUB is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GRUB. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <grub/mm.h> +#include <grub/misc.h> + +#include <grub/types.h> +#include <grub/types.h> +#include <grub/err.h> + +#include <grub/i386/relocator.h> + +extern grub_uint8_t grub_relocator32_forward_start; +extern grub_uint8_t grub_relocator32_forward_end; +extern grub_uint8_t grub_relocator32_backward_start; +extern grub_uint8_t grub_relocator32_backward_end; + +extern grub_uint32_t grub_relocator32_backward_dest; +extern grub_uint32_t grub_relocator32_backward_size; +#ifdef __x86_64__ +extern grub_uint64_t grub_relocator32_backward_src; +#else +extern grub_uint32_t grub_relocator32_backward_src; +#endif + +extern grub_uint32_t grub_relocator32_forward_dest; +extern grub_uint32_t grub_relocator32_forward_size; +#ifdef __x86_64__ +extern grub_uint64_t grub_relocator32_forward_src; +#else +extern grub_uint32_t grub_relocator32_forward_src; +#endif + +extern grub_uint32_t grub_relocator32_forward_eax; +extern grub_uint32_t grub_relocator32_forward_ebx; +extern grub_uint32_t grub_relocator32_forward_ecx; +extern grub_uint32_t grub_relocator32_forward_edx; +extern grub_uint32_t grub_relocator32_forward_eip; +extern grub_uint32_t grub_relocator32_forward_esp; + +extern grub_uint32_t grub_relocator32_backward_eax; +extern grub_uint32_t grub_relocator32_backward_ebx; +extern grub_uint32_t grub_relocator32_backward_ecx; +extern grub_uint32_t grub_relocator32_backward_edx; +extern grub_uint32_t grub_relocator32_backward_eip; +extern grub_uint32_t grub_relocator32_backward_esp; + +#define RELOCATOR_SIZEOF(x) (&grub_relocator32_##x##_end - &grub_relocator32_##x##_start) +#define RELOCATOR_ALIGN 16 + +void * +grub_relocator32_alloc (grub_size_t size) +{ + char *playground; + + playground = grub_malloc ((RELOCATOR_SIZEOF (forward) + RELOCATOR_ALIGN) + + size + + (RELOCATOR_SIZEOF (backward) + + RELOCATOR_ALIGN)); + if (!playground) + return 0; + + *(grub_size_t *) playground = size; + + return playground + RELOCATOR_SIZEOF (forward); +} + +void * +grub_relocator32_realloc (void *relocator, grub_size_t size) +{ + char *playground; + + playground = (char *) relocator - RELOCATOR_SIZEOF (forward); + + playground = grub_realloc (playground, + (RELOCATOR_SIZEOF (forward) + RELOCATOR_ALIGN) + + size + + (RELOCATOR_SIZEOF (backward) + RELOCATOR_ALIGN)); + if (!playground) + return 0; + + *(grub_size_t *) playground = size; + + return playground + RELOCATOR_SIZEOF (forward); +} + +void +grub_relocator32_free (void *relocator) +{ + if (relocator) + grub_free ((char *) relocator - RELOCATOR_SIZEOF (forward)); +} + + +grub_err_t +grub_relocator32_boot (void *relocator, grub_uint32_t dest, + struct grub_relocator32_state state) +{ + grub_size_t size; + char *playground; + void (*entry) (); + + playground = (char *) relocator - RELOCATOR_SIZEOF (forward); + size = *(grub_size_t *) playground; + + if (UINT_TO_PTR (dest) >= relocator) + { + int overhead; + + overhead = + ALIGN_UP (dest - RELOCATOR_SIZEOF (backward) - RELOCATOR_ALIGN, + RELOCATOR_ALIGN); + grub_relocator32_backward_dest = dest - overhead; + grub_relocator32_backward_src = PTR_TO_UINT64 (relocator - overhead); + grub_relocator32_backward_size = size + overhead; + + grub_relocator32_backward_eax = state.eax; + grub_relocator32_backward_ebx = state.ebx; + grub_relocator32_backward_ecx = state.ecx; + grub_relocator32_backward_edx = state.edx; + grub_relocator32_backward_eip = state.eip; + grub_relocator32_backward_esp = state.esp; + + grub_memmove (relocator - overhead, + &grub_relocator32_backward_start, + RELOCATOR_SIZEOF (backward)); + entry = (void (*)()) (relocator - overhead); + } + else + { + int overhead; + + overhead = ALIGN_UP (dest + size, RELOCATOR_ALIGN) + + RELOCATOR_SIZEOF (forward) - (dest + size); + + grub_relocator32_forward_dest = dest; + grub_relocator32_forward_src = PTR_TO_UINT64 (relocator); + grub_relocator32_forward_size = size + overhead; + + grub_relocator32_forward_eax = state.eax; + grub_relocator32_forward_ebx = state.ebx; + grub_relocator32_forward_ecx = state.ecx; + grub_relocator32_forward_edx = state.edx; + grub_relocator32_forward_eip = state.eip; + grub_relocator32_forward_esp = state.esp; + + grub_memmove (relocator + size + overhead - RELOCATOR_SIZEOF (forward), + &grub_relocator32_forward_start, + RELOCATOR_SIZEOF (forward)); + entry = + (void (*)()) (relocator + size + overhead - + RELOCATOR_SIZEOF (forward)); + } + entry (); + + /* Not reached. */ + return GRUB_ERR_NONE; +} diff --git a/lib/i386/relocator_asm.S b/lib/i386/relocator_asm.S new file mode 100644 index 0000000..d022a68 --- /dev/null +++ b/lib/i386/relocator_asm.S @@ -0,0 +1,273 @@ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2009 Free Software Foundation, Inc. + * + * GRUB is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * GRUB is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GRUB. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <grub/symbol.h> + +#ifdef BACKWARD +#define RELOCATOR_VARIABLE(x) VARIABLE(grub_relocator32_backward_ ## x) +#else +#define RELOCATOR_VARIABLE(x) VARIABLE(grub_relocator32_forward_ ## x) +#endif + .p2align 4 /* force 16-byte alignment */ + +RELOCATOR_VARIABLE(start) +#ifdef BACKWARD +base: +#endif + cli + +#ifndef __x86_64__ + /* mov imm32, %eax */ + .byte 0xb8 +RELOCATOR_VARIABLE(dest) + .long 0 + mov %eax, %edi + + /* mov imm32, %eax */ + .byte 0xb8 +RELOCATOR_VARIABLE(src) + .long 0 + mov %eax, %esi + + /* mov imm32, %ecx */ + .byte 0xb9 +RELOCATOR_VARIABLE(size) + .long 0 + mov %edi, %eax +#ifndef BACKWARD + add %ecx, %eax +#endif + add $0x3, %ecx + shr $2, %ecx + +#ifdef BACKWARD + /* Backward movsl is implicitly off-by-four. compensate that. */ + subl $4, %esi + subl $4, %edi + + /* Backward copy. */ + std + addl %ecx, %esi + addl %ecx, %edi + + rep + movsl + +#else + /* Forward copy. */ + cld + rep + movsl +#endif + /* %eax contains now our new base. */ + mov %eax, %esi + add $(cont0 - base), %eax + jmp *%eax +cont0: +#else + xorq %rax, %rax + + /* mov imm32, %eax */ + .byte 0xb8 +RELOCATOR_VARIABLE(dest) + .long 0 + mov %eax, %edi + + /* mov imm64, %rax */ + .byte 0x48 + .byte 0xb8 +RELOCATOR_VARIABLE(src) + .long 0, 0 + mov %rax, %rsi + + xorq %rcx, %rcx + /* mov imm32, %ecx */ + .byte 0xb9 +RELOCATOR_VARIABLE(size) + .long 0 + + mov %rdi, %rax +#ifndef BACKWARD + add %rcx, %rax +#endif + add $0x3, %rcx + shr $2, %rcx + +#ifdef BACKWARD + /* Backward movsl is implicitly off-by-four. compensate that. */ + subq $4, %rsi + subq $4, %rdi + + /* Backward copy. */ + std + addq %rcx, %rsi + addq %rcx, %rdi + + rep + movsl + +#else + /* Forward copy. */ + cld + rep + movsl +#endif + + /* %rax contains now our new 'base'. */ + mov %rax, %rsi +#ifdef APPLE_CC + add $(cont0 - base), %eax +#else + add $(cont0 - base), %rax +#endif + jmp *%rax +cont0: +#ifdef APPLE_CC + lea (cont1 - base) (%esi, 1), %eax + mov %eax, (jump_vector - base) (%esi, 1) + + lea (gdt - base) (%esi, 1), %eax + mov %eax, (gdt_addr - base) (%esi, 1) + + /* Switch to compatibility mode. */ + + lgdt (gdtdesc - base) (%esi, 1) + + /* Update %cs. Thanks to David Miller for pointing this mistake out. */ + ljmp *(jump_vector - base) (%esi,1) +#else + lea (cont1 - base) (%rsi, 1), %rax + mov %eax, (jump_vector - base) (%rsi, 1) + + lea (gdt - base) (%rsi, 1), %rax + mov %rax, (gdt_addr - base) (%rsi, 1) + + /* Switch to compatibility mode. */ + + lgdt (gdtdesc - base) (%rsi, 1) + + /* Update %cs. Thanks to David Miller for pointing this mistake out. */ + ljmp *(jump_vector - base) (%rsi, 1) +#endif + +cont1: + .code32 + + /* Update other registers. */ + mov $0x18, %eax + mov %eax, %ds + mov %eax, %es + mov %eax, %fs + mov %eax, %gs + mov %eax, %ss + + /* Disable paging. */ + mov %cr0, %eax + and $0x7fffffff, %eax + mov %eax, %cr0 + + /* Disable amd64. */ + mov $0xc0000080, %ecx + rdmsr + and $0xfffffeff, %eax + wrmsr + + /* Turn off PAE. */ + movl %cr4, %eax + and $0xffffffcf, %eax + mov %eax, %cr4 + + jmp cont2 +cont2: +#endif + .code32 + + /* mov imm32, %eax */ + .byte 0xb8 +RELOCATOR_VARIABLE (esp) + .long 0 + + movl %eax, %esp + + /* mov imm32, %eax */ + .byte 0xb8 +RELOCATOR_VARIABLE (eax) + .long 0 + + /* mov imm32, %ebx */ + .byte 0xbb +RELOCATOR_VARIABLE (ebx) + .long 0 + + /* mov imm32, %ecx */ + .byte 0xb9 +RELOCATOR_VARIABLE (ecx) + .long 0 + + /* mov imm32, %edx */ + .byte 0xba +RELOCATOR_VARIABLE (edx) + .long 0 + + /* Cleared direction flag is of no problem with any current + payload and makes this implementation easier. */ + cld + + .byte 0xea +RELOCATOR_VARIABLE (eip) + .long 0 +#ifdef __x86_64__ + .word 0x10 +#else + .word 0x08 +#endif + +#ifdef __x86_64__ + /* GDT. Copied from loader/i386/linux.c. */ + .p2align 4 +gdt: + /* NULL. */ + .byte 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 + + /* Reserved. */ + .byte 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 + + /* Code segment. */ + .byte 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x9A, 0xCF, 0x00 + + /* Data segment. */ + .byte 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x92, 0xCF, 0x00 + +gdtdesc: + .word 31 +gdt_addr: + /* Filled by the code. */ + .quad 0 + + .p2align 4 +jump_vector: + /* Jump location. Is filled by the code */ + .long 0 + .long 0x10 +#endif + +#ifndef BACKWARD +base: +#endif + +RELOCATOR_VARIABLE(end) diff --git a/lib/i386/relocator_backward.S b/lib/i386/relocator_backward.S new file mode 100644 index 0000000..0691347 --- /dev/null +++ b/lib/i386/relocator_backward.S @@ -0,0 +1,2 @@ +#define BACKWARD +#include "relocator_asm.S"
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