Hi Simon,
-----Original Message----- From: Simon Glass sjg@chromium.org Sent: Sunday, April 26, 2020 1:16 PM To: Park, Aiden aiden.park@intel.com Cc: Bin Meng bmeng.cn@gmail.com; U-Boot Mailing List <u- boot@lists.denx.de> Subject: Re: [PATCH 2/8] x86: start64: Add a hook at 64-bit entry
Hi Aiden,
On Tue, 21 Apr 2020 at 18:45, aiden.park@intel.com wrote:
From: Aiden Park aiden.park@intel.com
This will allow a board or cpu to do its specific initialization at 64-bit entry if U-Boot is a pure 64-bit binary.
Signed-off-by: Aiden Park aiden.park@intel.com
arch/x86/cpu/start64.S | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/arch/x86/cpu/start64.S b/arch/x86/cpu/start64.S index 7be834788b..b8ac5aab57 100644 --- a/arch/x86/cpu/start64.S +++ b/arch/x86/cpu/start64.S @@ -13,6 +13,11 @@ .globl _start .type _start, @function _start: +#if defined(CONFIG_X86_RUN_64BIT_ONLY)
jmp init_64bit_entry+.globl init_64bit_entry_ret +init_64bit_entry_ret: +#endif
Would it be safe to do this always? Is that a standard register to have the HOB pointer be in? If so, we could always store it. We could also make sure that U- Boot passes it on too.
Unfortunately, it's not. This is to cover pre-stage firmware's calling convention. The calling convention of 64-bit Slim Bootloader is that HOB address is in rcx.
Note that U-Boot has a struct arch_spl_handoff which is how it passes the HOB through.
Thanks for your information. Let me try to leverage arch_spl_handoff to pass HOB.
/* Set up memory using the existing stack */ mov %rsp, %rdi call board_init_f_alloc_reserve-- 2.20.1
Regards, Simon
Best Regards, Aiden