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x86: Pass relocation offset into Global Data

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In order to locate the 16-bit BIOS code, we need to know the reloaction
offset.

Signed-off-by: Graeme Russ <graeme.russ@gmail.com>
This commit is contained in:
Graeme Russ 2010-04-24 00:05:44 +10:00 • committed by Wolfgang Denk
parent c14a3669b2
commit 2fb1bc4f53
1 changed files with 36 additions and 27 deletions
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63
arch/i386/lib/board.c
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@ -52,7 +52,9 @@ extern ulong _i386boot_rel_dyn_start;
extern ulong _i386boot_rel_dyn_end; extern ulong _i386boot_rel_dyn_end;
extern ulong _i386boot_bss_start; extern ulong _i386boot_bss_start;
extern ulong _i386boot_bss_size; extern ulong _i386boot_bss_size;
void ram_bootstrap (void *);
void ram_bootstrap (void *, ulong);
const char version_string[] = const char version_string[] =
U_BOOT_VERSION" (" U_BOOT_DATE " - " U_BOOT_TIME ")"; U_BOOT_VERSION" (" U_BOOT_DATE " - " U_BOOT_TIME ")";
@ -162,6 +164,7 @@ init_fnc_t *init_sequence[] = {
NULL, NULL,
}; };
static gd_t gd_data;
gd_t *gd; gd_t *gd;
/* /*
@ -174,21 +177,18 @@ void board_init_f (ulong stack_limit)
Elf32_Rel *rel_dyn_start = (Elf32_Rel *)&_i386boot_rel_dyn_start; Elf32_Rel *rel_dyn_start = (Elf32_Rel *)&_i386boot_rel_dyn_start;
Elf32_Rel *rel_dyn_end = (Elf32_Rel *)&_i386boot_rel_dyn_end; Elf32_Rel *rel_dyn_end = (Elf32_Rel *)&_i386boot_rel_dyn_end;
void *bss_start = &_i386boot_bss_start; void *bss_start = &_i386boot_bss_start;
void *bss_size = &_i386boot_bss_size; ulong bss_size = (ulong)&_i386boot_bss_size;
size_t uboot_size; ulong uboot_size;
void *ram_start; void *dest_addr;
ulong rel_offset; ulong rel_offset;
Elf32_Rel *re; Elf32_Rel *re;
void (*start_func)(void *); void (*start_func)(void *, ulong);
/* compiler optimization barrier needed for GCC >= 3.4 */ uboot_size = (ulong)u_boot_cmd_end - (ulong)text_start;
__asm__ __volatile__("": : :"memory"); dest_addr = (void *)stack_limit - (uboot_size + (ulong)bss_size);
rel_offset = text_start - dest_addr;
uboot_size = (size_t)u_boot_cmd_end - (size_t)text_start;
ram_start = (void *)stack_limit - (uboot_size + (ulong)bss_size);
rel_offset = text_start - ram_start;
start_func = ram_bootstrap - rel_offset; start_func = ram_bootstrap - rel_offset;
/* First stage CPU initialization */ /* First stage CPU initialization */
@ -200,10 +200,10 @@ void board_init_f (ulong stack_limit)
hang(); hang();
/* Copy U-Boot into RAM */ /* Copy U-Boot into RAM */
memcpy(ram_start, text_start, (size_t)uboot_size); memcpy(dest_addr, text_start, uboot_size);
/* Clear BSS */ /* Clear BSS */
memset(bss_start - rel_offset, 0, (size_t)bss_size); memset(bss_start - rel_offset, 0, bss_size);
/* Perform relocation adjustments */ /* Perform relocation adjustments */
for (re = rel_dyn_start; re < rel_dyn_end; re++) for (re = rel_dyn_start; re < rel_dyn_end; re++)
@ -213,27 +213,39 @@ void board_init_f (ulong stack_limit)
*(ulong *)(re->r_offset - rel_offset) -= (Elf32_Addr)rel_offset; *(ulong *)(re->r_offset - rel_offset) -= (Elf32_Addr)rel_offset;
} }
start_func(ram_start); /* Enter the relocated U-Boot! */
start_func(dest_addr, rel_offset);
/* NOTREACHED - relocate_code() does not return */ /* NOTREACHED - board_init_f() does not return */
while(1); while(1);
} }
/* /*
* All attempts to jump straight from board_init_f() to board_init_r() * We cannot initialize gd_data in board_init_f() because we would be
* have failed, hence this special 'bootstrap' function. * attempting to write to flash (I have even tried using manual relocation
* adjustments on pointers but it just won't work) and board_init_r() does
* not have enough arguments to allow us to pass the relocation offset
* straight up. This bootstrap function (which runs in RAM) is used to
* setup gd_data in order to pass the relocation offset to the rest of
* U-Boot.
*
* TODO: The compiler optimization barrier is intended to stop GCC from
* optimizing this function into board_init_f(). It seems to work without
* it, but I've left it in to be sure. I think also that the barrier in
* board_init_r() is no longer needed, but left it in 'just in case'
*/ */
void ram_bootstrap (void *ram_start) void ram_bootstrap (void *dest_addr, ulong rel_offset)
{ {
static gd_t gd_data;
/* compiler optimization barrier needed for GCC >= 3.4 */ /* compiler optimization barrier needed for GCC >= 3.4 */
__asm__ __volatile__("": : :"memory"); __asm__ __volatile__("": : :"memory");
board_init_r(&gd_data, (ulong)ram_start); /* tell others: relocation done */
gd_data.reloc_off = rel_offset;
gd_data.flags |= GD_FLG_RELOC;
board_init_r(&gd_data, (ulong)dest_addr);
} }
void board_init_r(gd_t *id, ulong ram_start) void board_init_r(gd_t *id, ulong dest_addr)
{ {
char *s; char *s;
int i; int i;
@ -247,16 +259,13 @@ void board_init_r(gd_t *id, ulong ram_start)
/* compiler optimization barrier needed for GCC >= 3.4 */ /* compiler optimization barrier needed for GCC >= 3.4 */
__asm__ __volatile__("": : :"memory"); __asm__ __volatile__("": : :"memory");
memset (gd, 0, sizeof (gd_t));
gd->bd = &bd_data; gd->bd = &bd_data;
memset (gd->bd, 0, sizeof (bd_t)); memset (gd->bd, 0, sizeof (bd_t));
show_boot_progress(0x22); show_boot_progress(0x22);
gd->baudrate = CONFIG_BAUDRATE; gd->baudrate = CONFIG_BAUDRATE;
gd->flags |= GD_FLG_RELOC; /* tell others: relocation done */ mem_malloc_init((((ulong)dest_addr - CONFIG_SYS_MALLOC_LEN)+3)&~3,
mem_malloc_init((((ulong)ram_start - CONFIG_SYS_MALLOC_LEN)+3)&~3,
CONFIG_SYS_MALLOC_LEN); CONFIG_SYS_MALLOC_LEN);
for (init_fnc_ptr = init_sequence, i=0; *init_fnc_ptr; ++init_fnc_ptr, i++) { for (init_fnc_ptr = init_sequence, i=0; *init_fnc_ptr; ++init_fnc_ptr, i++) {