Hi Simon, > -----Original Message----- > From: Simon Glass <s...@chromium.org> > Sent: Sunday, April 26, 2020 1:16 PM > To: Park, Aiden <aiden.p...@intel.com> > Cc: Bin Meng <bmeng...@gmail.com>; U-Boot Mailing List <u- > b...@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.p...@intel.com> wrote: > > > > From: Aiden Park <aiden.p...@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.p...@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
