linux-kernel - Re: [PATCH v3 1/6] x86/bugs: Rename entry

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Message-ID: <20250402182928.GAZ-2CCBR2BAgpwVLf@fat_crate.local>
Date: Wed, 2 Apr 2025 20:29:28 +0200
From: Borislav Petkov <bp@...en8.de>
To: Josh Poimboeuf <jpoimboe@...nel.org>
Cc: x86@...nel.org, linux-kernel@...r.kernel.org, amit@...nel.org,
	kvm@...r.kernel.org, amit.shah@....com, thomas.lendacky@....com,
	tglx@...utronix.de, peterz@...radead.org,
	pawan.kumar.gupta@...ux.intel.com, corbet@....net, mingo@...hat.com,
	dave.hansen@...ux.intel.com, hpa@...or.com, seanjc@...gle.com,
	pbonzini@...hat.com, daniel.sneddon@...ux.intel.com,
	kai.huang@...el.com, sandipan.das@....com,
	boris.ostrovsky@...cle.com, Babu.Moger@....com,
	david.kaplan@....com, dwmw@...zon.co.uk, andrew.cooper3@...rix.com
Subject: Re: [PATCH v3 1/6] x86/bugs: Rename entry_ibpb()

On Wed, Apr 02, 2025 at 11:19:18AM -0700, Josh Poimboeuf wrote:
> There's nothing entry-specific about entry_ibpb().  In preparation for

Not anymore - it was done on entry back then AFAIR.

> calling it from elsewhere, rename it to __write_ibpb().
> 
> Signed-off-by: Josh Poimboeuf <jpoimboe@...nel.org>
> ---
>  arch/x86/entry/entry.S               | 7 ++++---
>  arch/x86/include/asm/nospec-branch.h | 6 +++---
>  arch/x86/kernel/cpu/bugs.c           | 6 +++---
>  3 files changed, 10 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/x86/entry/entry.S b/arch/x86/entry/entry.S
> index d3caa31240ed..3a53319988b9 100644
> --- a/arch/x86/entry/entry.S
> +++ b/arch/x86/entry/entry.S
> @@ -17,7 +17,8 @@
>  
>  .pushsection .noinstr.text, "ax"
>  
> -SYM_FUNC_START(entry_ibpb)
> +// Clobbers AX, CX, DX

Why the ugly comment style if the rest of the file is already using the
multiline one...

> +SYM_FUNC_START(__write_ibpb)

... and why the __ ?

>  	ANNOTATE_NOENDBR
>  	movl	$MSR_IA32_PRED_CMD, %ecx
>  	movl	$PRED_CMD_IBPB, %eax

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette