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2008-08-12 Robert Millan <rmh@aybabtu.com>

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* loader/i386/pc/multiboot.c (grub_multiboot_load_elf32): Move part
        of the relocation code from here ...
        (grub_multiboot): ... to here.
        (forward_relocator, backward_relocator): Move from here ...
        * kern/i386/loader.S (grub_multiboot_forward_relocator)
        (grub_multiboot_backward_relocator): ... to here.
        (grub_multiboot_real_boot): Use %edx for entry offset.  Put Multiboot
        magic in %eax.  Use %ebp for jumping (so %edx is not trashed).
        * include/grub/i386/loader.h (grub_multiboot_forward_relocator)
        (grub_multiboot_forward_relocator_end)
        (grub_multiboot_backward_relocator)
        (grub_multiboot_backward_relocator_end): New variables.
This commit is contained in:
robertmh 2008-08-12 15:40:26 +00:00
parent 05f9452b12
commit 371458b576
4 changed files with 113 additions and 56 deletions
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15
ChangeLog
View file

@ -1,3 +1,18 @@
2008-08-12 Robert Millan <rmh@aybabtu.com>
* loader/i386/pc/multiboot.c (grub_multiboot_load_elf32): Move part
of the relocation code from here ...
(grub_multiboot): ... to here.
(forward_relocator, backward_relocator): Move from here ...
* kern/i386/loader.S (grub_multiboot_forward_relocator)
(grub_multiboot_backward_relocator): ... to here.
(grub_multiboot_real_boot): Use %edx for entry offset. Put Multiboot
magic in %eax. Use %ebp for jumping (so %edx is not trashed).
* include/grub/i386/loader.h (grub_multiboot_forward_relocator)
(grub_multiboot_forward_relocator_end)
(grub_multiboot_backward_relocator)
(grub_multiboot_backward_relocator_end): New variables.
2008-08-12 Bean <bean123ch@gmail.com>
* disk/raid.c (grub_raid_read): Fix a bug in raid0 code.

7
include/grub/i386/loader.h
View file

@ -53,4 +53,11 @@ extern grub_uint32_t EXPORT_VAR(grub_multiboot_payload_entry_offset);
void grub_rescue_cmd_linux (int argc, char *argv[]);
void grub_rescue_cmd_initrd (int argc, char *argv[]);
extern grub_uint8_t EXPORT_VAR(grub_multiboot_forward_relocator);
extern grub_uint8_t EXPORT_VAR(grub_multiboot_forward_relocator_end);
extern grub_uint8_t EXPORT_VAR(grub_multiboot_backward_relocator);
extern grub_uint8_t EXPORT_VAR(grub_multiboot_backward_relocator_end);
#define RELOCATOR_SIZEOF(x) (&grub_multiboot_##x##_relocator_end - &grub_multiboot_##x##_relocator)
#endif /* ! GRUB_LOADER_CPU_HEADER */

39
kern/i386/loader.S
View file

@ -132,6 +132,36 @@ VARIABLE(grub_multiboot_payload_dest)
VARIABLE(grub_multiboot_payload_entry_offset)
.long 0
/*
* The relocators below understand the following parameters:
* ecx: Size of the block to be copied.
* esi: Where to copy from (always lowest address, even if we're relocating
* backwards).
* edi: Where to copy to (likewise).
* edx: Offset of the entry point (relative to the beginning of the block).
*/
VARIABLE(grub_multiboot_forward_relocator)
cld
addl %edi, %edx
rep
movsb
jmp *%edx
VARIABLE(grub_multiboot_forward_relocator_end)
VARIABLE(grub_multiboot_backward_relocator)
std
addl %ecx, %esi
addl %ecx, %edi
/* backward movsb is implicitly off-by-one. compensate that. */
incl %ecx
rep
movsb
/* same problem again. */
incl %edi
addl %edi, %edx
jmp *%edx
VARIABLE(grub_multiboot_backward_relocator_end)
FUNCTION(grub_multiboot_real_boot)
/* Push the entry address on the stack. */
pushl %eax
@ -149,11 +179,14 @@ FUNCTION(grub_multiboot_real_boot)
movl EXT_C(grub_multiboot_payload_size), %ecx
movl EXT_C(grub_multiboot_payload_orig), %esi
movl EXT_C(grub_multiboot_payload_dest), %edi
movl EXT_C(grub_multiboot_payload_entry_offset), %eax
movl EXT_C(grub_multiboot_payload_entry_offset), %edx
/* Move the magic value into eax. */
movl $MULTIBOOT_MAGIC2, %eax
/* Jump to the relocator. */
popl %edx
jmp *%edx
popl %ebp
jmp *%ebp
/*
* This starts the multiboot 2 kernel.

104
loader/i386/pc/multiboot.c
View file

@ -52,31 +52,6 @@ static grub_addr_t entry;
static char *playground = NULL;
static grub_uint8_t forward_relocator[] =
{
0xfc, /* cld */
0x89, 0xf2, /* movl %esi, %edx */
0xf3, 0xa4, /* rep movsb */
0x01, 0xc2, /* addl %eax, %edx */
0xb8, 0x02, 0xb0, 0xad, 0x2b, /* movl $MULTIBOOT_MAGIC2, %eax */
0xff, 0xe2, /* jmp *%edx */
};
static grub_uint8_t backward_relocator[] =
{
0xfd, /* std */
0x01, 0xce, /* addl %ecx, %esi */
0x01, 0xcf, /* addl %ecx, %edi */
/* backward movsb is implicitly off-by-one. compensate that. */
0x41, /* incl %ecx */
0xf3, 0xa4, /* rep movsb */
/* same problem again. */
0x47, /* incl %edi */
0x01, 0xc7, /* addl %eax, %edi */
0xb8, 0x02, 0xb0, 0xad, 0x2b, /* movl $MULTIBOOT_MAGIC2, %eax */
0xff, 0xe7, /* jmp *%edi */
};
static grub_err_t
grub_multiboot_boot (void)
{
@ -155,16 +130,11 @@ grub_multiboot_load_elf32 (grub_file_t file, void *buffer)
grub_multiboot_payload_size = (phdr(highest_segment)->p_paddr + phdr(highest_segment)->p_memsz) - phdr(lowest_segment)->p_paddr;
grub_multiboot_payload_dest = phdr(lowest_segment)->p_paddr;
if (playground)
grub_free (playground);
playground = grub_malloc (sizeof (forward_relocator) + grub_multiboot_payload_size + sizeof (backward_relocator));
playground = grub_malloc (RELOCATOR_SIZEOF(forward) + grub_multiboot_payload_size + RELOCATOR_SIZEOF(backward));
if (! playground)
return grub_errno;
grub_multiboot_payload_orig = (long) playground + sizeof (forward_relocator);
grub_memmove (playground, forward_relocator, sizeof (forward_relocator));
grub_memmove ((char *) (grub_multiboot_payload_orig + grub_multiboot_payload_size), backward_relocator, sizeof (backward_relocator));
grub_multiboot_payload_orig = (long) playground + RELOCATOR_SIZEOF(forward);
/* Load every loadable segment in memory. */
for (i = 0; i < ehdr->e_phnum; i++)
@ -196,16 +166,6 @@ grub_multiboot_load_elf32 (grub_file_t file, void *buffer)
#undef phdr
if (grub_multiboot_payload_dest >= grub_multiboot_payload_orig)
entry = (grub_addr_t) playground;
else
entry = (grub_addr_t) grub_multiboot_payload_orig + grub_multiboot_payload_size;
grub_dprintf ("multiboot_loader", "dest=%p, size=0x%x, entry_offset=0x%x\n",
(void *) grub_multiboot_payload_dest,
grub_multiboot_payload_size,
grub_multiboot_payload_entry_offset);
return grub_errno;
}
@ -413,24 +373,66 @@ grub_multiboot (int argc, char *argv[])
goto fail;
}
if (playground)
{
grub_free (playground);
playground = NULL;
}
if (header->flags & MULTIBOOT_AOUT_KLUDGE)
{
int ofs;
int offset = ((char *) header - buffer -
(header->header_addr - header->load_addr));
int load_size = ((header->load_end_addr == 0) ? file->size - offset :
header->load_end_addr - header->load_addr);
ofs = (char *) header - buffer -
(header->header_addr - header->load_addr);
if ((grub_aout_load (file, ofs, header->load_addr,
((header->load_end_addr == 0) ? 0 :
header->load_end_addr - header->load_addr),
header->bss_end_addr))
!=GRUB_ERR_NONE)
if (header->bss_end_addr)
grub_multiboot_payload_size = (header->bss_end_addr - header->load_addr);
else
grub_multiboot_payload_size = load_size;
grub_multiboot_payload_dest = header->load_addr;
playground = grub_malloc (RELOCATOR_SIZEOF(forward) + grub_multiboot_payload_size + RELOCATOR_SIZEOF(backward));
if (! playground)
goto fail;
entry = header->entry_addr;
grub_multiboot_payload_orig = (long) playground + RELOCATOR_SIZEOF(forward);
if ((grub_file_seek (file, offset)) == (grub_off_t) - 1)
goto fail;
grub_file_read (file, grub_multiboot_payload_orig, load_size);
if (grub_errno)
goto fail;
if (header->bss_end_addr)
grub_memset (grub_multiboot_payload_orig + load_size, 0,
header->bss_end_addr - header->load_addr - load_size);
grub_multiboot_payload_entry_offset = header->entry_addr - header->load_addr;
}
else if (grub_multiboot_load_elf (file, buffer) != GRUB_ERR_NONE)
goto fail;
if (grub_multiboot_payload_dest >= grub_multiboot_payload_orig)
{
grub_memmove (playground, &grub_multiboot_forward_relocator, RELOCATOR_SIZEOF(forward));
entry = (grub_addr_t) playground;
}
else
{
grub_memmove ((char *) (grub_multiboot_payload_orig + grub_multiboot_payload_size),
&grub_multiboot_backward_relocator, RELOCATOR_SIZEOF(backward));
entry = (grub_addr_t) grub_multiboot_payload_orig + grub_multiboot_payload_size;
}
grub_dprintf ("multiboot_loader", "dest=%p, size=0x%x, entry_offset=0x%x\n",
(void *) grub_multiboot_payload_dest,
grub_multiboot_payload_size,
grub_multiboot_payload_entry_offset);
mbi = grub_malloc (sizeof (struct grub_multiboot_info));
if (! mbi)
goto fail;