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.cn@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(sjg@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)