Re: [PATCH 14/43] x86/entry/64: Return to userspace from the trampoline stack

[Thomas Gleixner]

On Fri, 24 Nov 2017, Ingo Molnar wrote:

> From: Andy Lutomirski <luto@xxxxxxxxxx>
> 
> By itself, this is useless.  It gives us the ability to run some final
> code before exit that cannnot run on the kernel stack.  This could
> include a CR3 switch a la KAISER or some kernel stack erasing, for
> example.  (Or even weird things like *changing* which kernel stack
> gets used as an ASLR-strengthening mechanism.)
> 
> The SYSRET32 path is not covered yet.  It could be in the future or
> we could just ignore it and force the slow path if needed.
> 
> Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>

Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>