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From: Borislav Petkov <bp@alien8.de>
To: "H. Peter Anvin (Intel)" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Andy Lutomirski <luto@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	x86@kernel.org
Subject: Re: [PATCH v2 0/2] x86/asm: avoid register pressure from static_cpu_has()
Date: Fri, 10 Sep 2021 15:24:30 +0200	[thread overview]
Message-ID: <YTtcjhrWS8e9VfWG@zn.tnic> (raw)
In-Reply-To: <YTsif1FeOEyFJnqc@zn.tnic>

On Fri, Sep 10, 2021 at 11:16:47AM +0200, Borislav Petkov wrote:
> Right, maybe I'm missing something but what is wrong with the immediate
> addressing variant, i.e., that thing:
> 
> 	testb  $0x8,0xffffffff89346eea
> 
> and you need to *force* %rip-relative?

To answer my own question after peterz asked: that hardcoded address
won't work with KASLR, ofc.

-- 
Regards/Gruss,
    Boris.

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

  reply	other threads:[~2021-09-10 13:24 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-08 17:17 [PATCH] x86/asm: pessimize the pre-initialization case in static_cpu_has() H. Peter Anvin (Intel)
2021-09-09 17:01 ` Borislav Petkov
2021-09-09 21:28   ` H. Peter Anvin
2021-09-09 21:53     ` Borislav Petkov
2021-09-09 22:17     ` H. Peter Anvin
2021-09-10  9:14       ` Borislav Petkov
2021-09-10 19:25         ` H. Peter Anvin
2021-09-09 22:08 ` [PATCH v2 0/2] x86/asm: avoid register pressure from static_cpu_has() H. Peter Anvin (Intel)
2021-09-09 22:08   ` [PATCH v2 1/2] x86/asm: add _ASM_RIP() macro for x86-64 (%rip) suffix H. Peter Anvin (Intel)
2021-09-09 22:08   ` [PATCH v2 2/2] x86/asm: pessimize the pre-initialization case in static_cpu_has() H. Peter Anvin (Intel)
2021-09-10  9:16   ` [PATCH v2 0/2] x86/asm: avoid register pressure from static_cpu_has() Borislav Petkov
2021-09-10 13:24     ` Borislav Petkov [this message]
2021-09-10 19:59 ` [PATCH v3 0/2] x86/asm: avoid register pressure from the init case in static_cpu_has() H. Peter Anvin (Intel)
2021-09-10 19:59   ` [PATCH] drm/bochs: add Bochs PCI ID for Simics model H. Peter Anvin (Intel)
2021-09-10 19:59   ` [PATCH v3 1/2] x86/asm: add _ASM_RIP() macro for x86-64 (%rip) suffix H. Peter Anvin (Intel)
2021-09-13 19:39     ` [tip: x86/cpu] x86/asm: Add " tip-bot2 for H. Peter Anvin (Intel)
2021-09-10 19:59   ` [PATCH v3 2/2] x86/asm: avoid adding register pressure for the init case in static_cpu_has() H. Peter Anvin (Intel)
2021-09-13 19:39     ` [tip: x86/cpu] x86/asm: Avoid " tip-bot2 for H. Peter Anvin

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