Re: [PATCH 2/2] x86/asm: Fix inline asm call constraints for clang

From: H. Peter Anvin
Date: Wed Sep 20 2017 - 13:58:01 EST


On 09/20/17 10:38, Dmitry Vyukov wrote:
>
> I think we need just the frame itself and RSP pointing below this
> frame. If we don't have a frame, CALL instruction will smash whatever
> RSP happens to point to. Compiler doesn't have to setup RSP to point
> below used part of stack in leaf functions.
>

In the kernel it does. Redzoning is not allowed in the kernel, because
interrupts or exceptions would also smash the redzone.

-hpa