Re: [PATCH 1/5] x86/mm/kaiser: Alternative ESPFIX

[Peter Zijlstra]

On Mon, Nov 27, 2017 at 11:31:11PM +0100, Peter Zijlstra wrote:
> Change the asm to do the CR3 switcheroo so we can remove the magic
> mappings.
> 
> Since RDI is unused after SWAPGS we can use it as a scratch reg for
> SWITCH_TO_KERNEL. And once we've computed the new RSP (in RAX) we no
> longer need RDI and can again use it as scratch reg for
> SWITCH_TO_USER.

Forgot to note; this passes tools/testing/selftests/x86/sigreturn_64.

> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>