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authorGraeme Russ <graeme.russ@gmail.com>2010-10-07 20:03:33 +1100
committerGraeme Russ <graeme.russ@gmail.com>2010-10-07 20:03:33 +1100
commitc868af3e57610b41c6ed4fd8d8744d8cc0a21b29 (patch)
tree6d2d1efd72aa3e7fc506f7ac65f106d163410ea5 /arch/i386
parentf2ff75c0a25eb78b4b86fd96c5f0be9dd327e2d7 (diff)
downloadu-boot-linaro-stable-c868af3e57610b41c6ed4fd8d8744d8cc0a21b29.tar.gz
x86: Implement fully relocatable image
u-boot.bin can be loaded at any 4-byte aligned memory location and directly 'jumped' to using the 'go' command using the load address as the start address. Doing so performs a 'warm boot' which skips memory initialisation and other low-level initialisations, relocates U-Boot to upper memory and starts U-Boot in RAM as per normal 'cold boot'
Diffstat (limited to 'arch/i386')
-rw-r--r--arch/i386/cpu/start.S6
-rw-r--r--arch/i386/include/asm/global_data.h28
-rw-r--r--arch/i386/lib/board.c25
3 files changed, 35 insertions, 24 deletions
diff --git a/arch/i386/cpu/start.S b/arch/i386/cpu/start.S
index 8fdcd81c1..829468fe7 100644
--- a/arch/i386/cpu/start.S
+++ b/arch/i386/cpu/start.S
@@ -118,6 +118,11 @@ mem_ok:
wbinvd
+ /* Determine our load offset */
+ call 1f
+1: popl %ecx
+ subl $1b, %ecx
+
/* Set the upper memory limit parameter */
subl $CONFIG_SYS_STACK_SIZE, %eax
@@ -127,6 +132,7 @@ mem_ok:
/* %eax points to the global data structure */
movl %esp, (GD_RAM_SIZE * 4)(%eax)
movl %ebx, (GD_FLAGS * 4)(%eax)
+ movl %ecx, (GD_LOAD_OFF * 4)(%eax)
call board_init_f /* Enter, U-boot! */
diff --git a/arch/i386/include/asm/global_data.h b/arch/i386/include/asm/global_data.h
index a15c5981c..597112318 100644
--- a/arch/i386/include/asm/global_data.h
+++ b/arch/i386/include/asm/global_data.h
@@ -41,6 +41,7 @@ typedef struct {
unsigned long baudrate;
unsigned long have_console; /* serial_init() was called */
unsigned long reloc_off; /* Relocation Offset */
+ unsigned long load_off; /* Load Offset */
unsigned long env_addr; /* Address of Environment struct */
unsigned long env_valid; /* Checksum of Environment valid? */
unsigned long cpu_clk; /* CPU clock in Hz! */
@@ -56,20 +57,21 @@ extern gd_t *gd;
#endif
/* Word Offsets into Global Data - MUST match struct gd_t */
-#define GD_BD 0
-#define GD_FLAGS 1
-#define GD_BAUDRATE 2
-#define GD_HAVE_CONSOLE 3
-#define GD_RELOC_OFF 4
-#define GD_ENV_ADDR 5
-#define GD_ENV_VALID 6
-#define GD_CPU_CLK 7
-#define GD_BUS_CLK 8
-#define GD_RAM_SIZE 9
-#define GD_RESET_STATUS 10
-#define GD_JT 11
+#define GD_BD 0
+#define GD_FLAGS 1
+#define GD_BAUDRATE 2
+#define GD_HAVE_CONSOLE 3
+#define GD_RELOC_OFF 4
+#define GD_LOAD_OFF 5
+#define GD_ENV_ADDR 6
+#define GD_ENV_VALID 7
+#define GD_CPU_CLK 8
+#define GD_BUS_CLK 9
+#define GD_RAM_SIZE 10
+#define GD_RESET_STATUS 11
+#define GD_JT 12
-#define GD_SIZE 12
+#define GD_SIZE 13
/*
* Global Data Flags
diff --git a/arch/i386/lib/board.c b/arch/i386/lib/board.c
index 9c2f77fd5..1129918fe 100644
--- a/arch/i386/lib/board.c
+++ b/arch/i386/lib/board.c
@@ -190,18 +190,21 @@ void board_init_f (ulong gdp)
dest_addr = (void *)gdp - (bss_end - text_start);
rel_offset = text_start - dest_addr;
- /* First stage CPU initialization */
- if (cpu_init_f() != 0)
- hang();
-
- /* First stage Board initialization */
- if (board_early_init_f() != 0)
- hang();
+ /* Perform low-level initialization only when cold booted */
+ if (((gd_t *)gdp)->flags & GD_FLG_COLD_BOOT) {
+ /* First stage CPU initialization */
+ if (cpu_init_f() != 0)
+ hang();
+
+ /* First stage Board initialization */
+ if (board_early_init_f() != 0)
+ hang();
+ }
/* Copy U-Boot into RAM */
dst_addr = (ulong *)dest_addr;
- src_addr = (ulong *)text_start;
- end_addr = (ulong *)data_end;
+ src_addr = (ulong *)(text_start + ((gd_t *)gdp)->load_off);
+ end_addr = (ulong *)(data_end + ((gd_t *)gdp)->load_off);
while (src_addr < end_addr)
*dst_addr++ = *src_addr++;
@@ -214,8 +217,8 @@ void board_init_f (ulong gdp)
*dst_addr++ = 0x00000000;
/* Perform relocation adjustments */
- re_src = (Elf32_Rel *)rel_dyn_start;
- re_end = (Elf32_Rel *)rel_dyn_end;
+ re_src = (Elf32_Rel *)(rel_dyn_start + ((gd_t *)gdp)->load_off);
+ re_end = (Elf32_Rel *)(rel_dyn_end + ((gd_t *)gdp)->load_off);
do {
if (re_src->r_offset >= TEXT_BASE)