linux-kernel - Re: [PATCH 4/6] x86/gsseg: move local_irq_save/restore() into asm_load_gs

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Message-ID: <Y0A8mWvT0mLm3nVD@hirez.programming.kicks-ass.net>
Date:   Fri, 7 Oct 2022 16:50:01 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Xin Li <xin3.li@...el.com>
Cc:     linux-kernel@...r.kernel.org, x86@...nel.org, tglx@...utronix.de,
        mingo@...hat.com, bp@...en8.de, dave.hansen@...ux.intel.com,
        hpa@...or.com
Subject: Re: [PATCH 4/6] x86/gsseg: move local_irq_save/restore() into
 asm_load_gs_index()

On Thu, Oct 06, 2022 at 08:40:39AM -0700, Xin Li wrote:
>  SYM_FUNC_START(asm_load_gs_index)
>  	FRAME_BEGIN
> +	pushf
> +	pop	%rax
> +	andl	$X86_EFLAGS_IF, %eax	/* Interrupts enabled? */
> +	jz	1f
> +	cli
> +1:

Why the pop,andl,jz ? AFAICT our arch_local_irq_save() doesn't even
bother with that, why does this function.