Re: [PATCH v3 2/5] x86/entry: Rename ignore_sysret

[Nikolay Borisov]

On 18.06.23 г. 23:51 ч., Thomas Gleixner wrote:
> On Fri, Jun 16 2023 at 15:57, Nikolay Borisov wrote:
>
> > Give ignore_sysret() a more descriptive name as it's actually used to make
> > 32bit syscalls return ENOSYS, rather than doing anything specific with
>
> That's not really correct. This is not about 32bit syscalls in general.
>
> It's specifically about the SYSCALL entry point on 32bit, right?
>
> The reason why this is required is because 32bit SYSCALL cannot be
> disabled in hardware.

How about:

"SYSCALL instruction cannot really be disabled in compatibility mode. 
The best that can be done is to configure the CSTAR msr with a minimal 
handler that returns directly some error value.

ignore_sysret is this minimal handler in the Linux kernel. Rename it by 
giving it a more descriptive name."

> Thanks,
>
>          tglx