Re: [PATCH] x86/mm: Remove broken vsyscall emulation code from the page fault code

From: Linus Torvalds
Date: Mon Apr 29 2024 - 20:06:08 EST


On Mon, 29 Apr 2024 at 16:30, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
>
> What strange page table handling do we do for XONLY?

Ahh, I misread set_vsyscall_pgtable_user_bits(). It's used for EMULATE
not for XONLY.

And the code in pti_setup_vsyscall() is just wrong, and does it for all cases.

> So I think we should remove EMULATE before removing XONLY.

Ok, looking at that again, I don't disagree. I misread that XONLY as
mapping it executable, but it is actually just mapping it readable

Yes, let's remove EMULATE, and keep XONLY.

Linus