At present in arch_setup_gd() it calls printch(' ') at the end which
has been a mystery for a long time as without such call the 64-bit
U-Boot just does not boot at all.
In fact this is due to the bug that board_init_f() was called with
boot_flags not being set. Hence whatever value being there in the
rdi register becomes the boot_flags if without such magic call.
With a printch(' ') call the rdi register is initialized as 0x20
and this value seems to be sane enough for the whole boot process.
Signed-off-by: Bin Meng <bmeng...@gmail.com>
---
arch/x86/cpu/start64.S | 1 +
arch/x86/cpu/x86_64/cpu.c | 18 ------------------
2 files changed, 1 insertion(+), 18 deletions(-)
diff --git a/arch/x86/cpu/start64.S b/arch/x86/cpu/start64.S
index a473fd1..a78a331 100644
--- a/arch/x86/cpu/start64.S
+++ b/arch/x86/cpu/start64.S
@@ -20,6 +20,7 @@ _start:
call board_init_f_init_reserve
+ xor %rdi, %rdi
call board_init_f
call board_init_f_r
diff --git a/arch/x86/cpu/x86_64/cpu.c b/arch/x86/cpu/x86_64/cpu.c
index ef5e812..6c063e8 100644
--- a/arch/x86/cpu/x86_64/cpu.c
+++ b/arch/x86/cpu/x86_64/cpu.c
@@ -19,24 +19,6 @@ struct global_data *global_data_ptr = (struct global_data
*)~0;
void arch_setup_gd(gd_t *new_gd)
{
global_data_ptr = new_gd;
-
- /*
- * TODO(s...@chromium.org): For some reason U-Boot does not boot
- * without this line. It fails to start up U-Boot proper and instead
- * restarts SPL. Need to figure out why:
- *
- * U-Boot SPL 2017.01
- *
- * U-Boot SPL 2017.01
- * CPU: Intel(R) Core(TM) i5-3427U CPU @ 1.80GHz
- * Trying to boot from SPIJumping to 64-bit U-Boot: Note many
- * features are missing
- *
- * U-Boot SPL 2017.01
- */
-#ifdef CONFIG_DEBUG_UART
- printch(' ');
-#endif
}
int cpu_has_64bit(void)
--
2.7.4
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