From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.alien8.de (mail.alien8.de [65.109.113.108]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 54D1321E082 for ; Tue, 16 Sep 2025 14:02:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=65.109.113.108 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758031371; cv=none; b=ts5vjO1HVFCdrd9aPdoL/N5VjB1lX5eGXdwCDAvucSFTOqH1W4VYixltLZasWmQstrBoWVyH/yPRE4craIbs2YMoFhJ1RDOlB40ivyou6w+QGoqoKtMiHoSHuahgNpVPt1Fe7R8qLCiCWFsyhHhYNItLA2DcDsxZQNQLsDS8zmw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758031371; c=relaxed/simple; bh=PrHDny6ZQpavYbWJP0mNeOkQflu1sgY9Zft6N5PA2Qw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=CNjWmD3ELFYaeE9se0dXu4h5N62UuYhjIuPKEGetiXdXVf1Ws5E6fskycx8DgZOHsaSiSFhRISR4uclW7/r+nwgN0KNLLznaUF0saasJmgIf88y0FYBmVci80kfmJUx93nhG0rQhU8EiHH/ejRcIAFtGy/tC63xgGw4YGSx6Ams= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de; spf=pass smtp.mailfrom=alien8.de; dkim=pass (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b=GENY26aQ; arc=none smtp.client-ip=65.109.113.108 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=alien8.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b="GENY26aQ" Received: from localhost (localhost.localdomain [127.0.0.1]) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with ESMTP id 0055A40E01AC; Tue, 16 Sep 2025 14:02:45 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at mail.alien8.de Authentication-Results: mail.alien8.de (amavisd-new); dkim=pass (4096-bit key) header.d=alien8.de Received: from mail.alien8.de ([127.0.0.1]) by localhost (mail.alien8.de [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id kkzBIUseLwba; Tue, 16 Sep 2025 14:02:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=alien8; t=1758031362; bh=6ARRZU+FBKxugU9+m/3ITFGtt9dlM7LwJqnpK0WQ02w=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=GENY26aQlofBSdSGwsfyoOyti2ffis540uc4wmK2no7mA9lCU8dvLOTcc1Zlf0XZG 1Kl8jxb/7wtK8lp9GCFMf6LGgI1vYCBit6/YF+6EoMaJXNMGDj7SIQ2kce4iZyqv5O PAWosbBKyY0meAqz3uC7xKpIIK4tdE82djTba+1H35dmnLpZgVGxUUxZhat5+4YNwJ MUZSCqTNnctBpFNetCAs7f+JuHwQUCthSnqn0hbn2t9FsG8F9HP8f0oFlmIriTq1aH 9j6LF9QMsobWXTpUq9rGD6v6vzDXgk8hB/tjwZkVCyvwZKfqBlAAV8yW1jtmk4av23 WSW1BCk87SicM1WtDnq07lwl0wDc+m9JchDHIpsD/cH/Mux8j7MIzk1uqB/zTVIHxZ i3m8+T/rFudM9569+HYTcdpbC9lpbk3e9wQ2MV44JgCluoKNXwFxPEpcpK+xfsIfnp nYYBZAnhraxxJD07so3oXFHCDK3FduffCI8KcRVNXJNb5w+Swy2scLR/gtjLvH8Vfr PdRgq5RG4UVNROdaFfAi6mJCr9VUMxeoMbduW2Td47jv8H+B6Nqmz0uYi8XC4TKtJN kbA9rsTcQwNNUeHNHd06rzj91OIqx5dFS+uO9xd8KIDl/4IDAz8bshF5KvBmh1U5eH pIymq6tW06YN2k2NEFF6QQDk= Received: from zn.tnic (p5de8ed27.dip0.t-ipconnect.de [93.232.237.39]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature ECDSA (P-256) server-digest SHA256) (No client certificate requested) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with UTF8SMTPSA id 6843940E01A3; Tue, 16 Sep 2025 14:02:33 +0000 (UTC) Date: Tue, 16 Sep 2025 16:02:27 +0200 From: Borislav Petkov To: Rong Zhang Cc: Thomas Gleixner , Ingo Molnar , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Mario Limonciello , Yazen Ghannam , linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86/CPU/AMD: Prevent reset reasons from being retained among boots Message-ID: <20250916140227.GGaMlt8xSp3eMI8Veu@fat_crate.local> References: <20250913144245.23237-1-i@rong.moe> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250913144245.23237-1-i@rong.moe> On Sat, Sep 13, 2025 at 10:42:45PM +0800, Rong Zhang wrote: > The S5_RESET_STATUS register is parsed on boot and printed to kmsg. > However, this could sometimes be misleading and lead to users wasting a > lot of time on meaningless debugging for two reasons: > > * Some bits are never cleared by hardware. It's the software's > responsibility to clear them as per the Processor Programming Reference > (see Link:). > > * Some rare hardware-initiated platform resets do not update the > register at all. > > In both cases, a previous reboot could leave its trace in the register, > resulting in users seeing unrelated reboot reasons while debugging > random reboots afterward. Just a heads-up: we're figuring out internally what the right thing to do here would be. Stay tuned. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette