linux-kernel - Re: [PATCH] x86/asm: Use asm_inline() instead of asm() in __untagged

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Message-ID: <20250314112504.GBZ9QSEL1hgjp376ey@fat_crate.local>
Date: Fri, 14 Mar 2025 12:25:04 +0100
From: Borislav Petkov <bp@...en8.de>
To: Uros Bizjak <ubizjak@...il.com>
Cc: x86@...nel.org, linux-kernel@...r.kernel.org,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...nel.org>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H. Peter Anvin" <hpa@...or.com>
Subject: Re: [PATCH] x86/asm: Use asm_inline() instead of asm() in
 __untagged_addr()

On Fri, Mar 14, 2025 at 10:30:55AM +0100, Uros Bizjak wrote:
> Use asm_inline() to instruct the compiler that the size of asm()
> is the minimum size of one instruction, ignoring how many instructions
> the compiler thinks it is. ALTERNATIVE macro that expands to several
> pseudo directives causes instruction length estimate to count
> more than 20 instructions.
> 
> bloat-o-meter reports minimal code size increase

If you see an increase and *no* *other* *palpable* improvement, you don't send
it. It is that simple.

-- 
Regards/Gruss,
    Boris.

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