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x86: Fix the mystery of printch() during 64-bit boot

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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>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
This commit is contained in:
Bin Meng 2018-10-13 20:52:09 -07:00
parent 2c78a79ec7
commit 49d5ff439c
2 changed files with 1 additions and 18 deletions
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1
arch/x86/cpu/start64.S
View File

@ -20,6 +20,7 @@ _start:
call board_init_f_init_reserve
xor %rdi, %rdi
call board_init_f
call board_init_f_r

18
arch/x86/cpu/x86_64/cpu.c
View File

@ -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)