linux-kernel - Re: [patch V3 27/66] x86/fpu: Rename copy_xregs_to_kernel() and copy_kernel_to

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Date:   Mon, 21 Jun 2021 20:00:06 +0200
From:   Borislav Petkov <bp@...e.de>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Andy Lutomirski <luto@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Fenghua Yu <fenghua.yu@...el.com>,
        Tony Luck <tony.luck@...el.com>,
        Yu-cheng Yu <yu-cheng.yu@...el.com>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Kan Liang <kan.liang@...ux.intel.com>
Subject: Re: [patch V3 27/66] x86/fpu: Rename copy_xregs_to_kernel() and
 copy_kernel_to_xregs()

On Fri, Jun 18, 2021 at 04:18:50PM +0200, Thomas Gleixner wrote:
> The function names for xsave[s]/xrstor[s] operations are horribly named and
> a permanent source of confusion.
> 
> Rename:
> 	copy_xregs_to_kernel() to os_xsave()
> 	copy_kernel_to_xregs() to os_xrstor()
> 
> These are truly low level wrappers around the actual instructions
> XSAVE[OPT]/XRSTOR and XSAVES/XRSTORS with the twist that the selection
> based on the available CPU features happens with an alternative to avoid
> conditionals all over the place and to provide the best performance for hot
> pathes.

"paths".

You need more elisp magic here. :)

> @@ -385,7 +390,7 @@ extern int copy_fpregs_to_fpstate(struct
>  static inline void __copy_kernel_to_fpregs(union fpregs_state *fpstate, u64 mask)
>  {
>  	if (use_xsave()) {
> -		copy_kernel_to_xregs(&fpstate->xsave, mask);
> +		os_xrstor(&fpstate->xsave, mask);

Yeah, this reads funny now:

	if use xsave, then xrstor.

and then later

	if use xsave, then xsave.

where latter makes perfect sense but former makes you stop and think for
a bit.

:-)

Regardless, it is still move in the right direction.

Reviewed-by: Borislav Petkov <bp@...e.de>

-- 
Regards/Gruss,
    Boris.

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