Re: [PATCH v13 00/16] Enable FSGSBASE instructions

From: Thomas Gleixner
Date: Thu Jun 18 2020 - 14:25:46 EST


Andy Lutomirski <luto@xxxxxxxxxx> writes:
> Is there a plan to deal with:
>
> /*
> * This function has some ABI oddities.
> *
> * A 32-bit ptracer probably expects that writing FS or GS will change
> * FSBASE or GSBASE respectively. In the absence of FSGSBASE support,
> * this code indeed has that effect. When FSGSBASE is added, this
> * will require a special case.
> *
> * For existing 64-bit ptracers, writing FS or GS *also* currently
> * changes the base if the selector is nonzero the next time the task
> * is run. This behavior may? not be needed, and trying to preserve it
> * when FSGSBASE is added would be complicated at best.
> */
>
> in arch/x86/kernel/ptrace.c?

Not that I'm aware of.