Re: [RFC 1/7] x86/asm/64: Allocate and enable the SYSENTER stack

[Dave Hansen]

On 11/10/2017 08:05 PM, Andy Lutomirski wrote:
> This will simplify some future code changes that will want some
> temporary stack space in more places.  It also lets us get rid of a
> SWAPGS_UNSAFE_STACK user.
> 
> This does not depend on CONFIG_IA32_EMULATION because we'll want the
> stack space even without IA32 emulation.

It was never clear to me why we don't use this on 64-bit today.  Does
anybody know why?