On Wed, Mar 02, 2016 at 10:39:05AM -0800, H. Peter Anvin wrote:
> Well, we definitely should use %rip-relative addressing if we can.
Right you are.
> However, even so I believe this breaks if the kernel is loaded anywhere
> but its default load address. I think we need to do something like:
>
> movq stack_start(%rip), %rax
> leaq __START_KERNEL_map(%rip), %rdx
> subq %rdx, %rax
> movq %rax, %rsp
>
> The use of temporary registers avoids clobbering a valid stack pointer
> for even a single instruction if we are given one.
Yeah, we should be prudent and make this as sturdy as possible. I did this:
CONFIG_PHYSICAL_START=0x100beef
and it aligned startup_64 up to ffffffff82000000. It seems to boot fine
in kvm. But better safe than sorry.
Thanks.
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
