From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.zytor.com (terminus.zytor.com [198.137.202.136]) (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 DF441208A7 for ; Fri, 21 Mar 2025 05:47:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.136 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742536080; cv=none; b=RA6H3dCFODDNH0dPtFoBgSr1py4qey2FjuV4RsHwpAkMkZ+9gvFTLXAyad+P9SM9FSjiePGCeTj6a4/ZEtouch35as0gDZpzFGsoq3wgTgj5yfk+xtcTaF7wSsw3oIpWYUyAyfreChsxUZMef0qyMB/JR5YP+rqWKfInofSxmD8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742536080; c=relaxed/simple; bh=063TSuyFySZQVcxA85BpXxV9BthpOA28nMtuSi3UF64=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Wc//hsv18xlYRNPCMkzOxvw3sUHHKbpsTNGsghMHCujcyXAZSjRqvp0ZCm3buPMZnrOuwYrSOgM7P9KLvQyZEat42P8nTMP8x9AXCO8WdZtF7bQw0FX4yCwXgum0QPLJaOK7gJGL4uyAsQLpda1kVbIlkFrT6UwYzFbcT+Ihi0k= ARC-Authentication-Results:i=1; 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h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=NAFIpQZrT/7ccRwmLxEMs2n3c2lE6Q/TuA6REe5+DFpTtfrNLYMkF+7a1mu9U9Gn5 grXbQ1o0+RCpOeorxssesKuew8zGvshftLgu9MoBYuO1ipM3k5EZVktK8HuiO9nZr1 gJEN2LJ1nGpoz612cUCHEts0GZ281ZYoo3pMIUn9UdDfuwQVTEpxfgiFxSSS7Eq4pS uZ117ygQUFAySbkk88ZpkgDccaLHCkCCy5XU/gG95GgXg6Kc6gauQY68pcQcT5zfA3 Sm2QzAR7XMBABrqwIpGwFvTIKyzK/Y384pdE/5N4Jy1+a1/ABEH0hGrwX9zTfssxDR eJJ0EneR+mdAg== Message-ID: <8b920da6-0c9a-43b4-bd50-79c057a01932@zytor.com> Date: Thu, 20 Mar 2025 22:47:25 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 3/3] x86: Zap TOP_OF_KERNEL_STACK_PADDING on x86_64 To: Brian Gerst Cc: linux-kernel@vger.kernel.org, luto@kernel.org, tglx@linutronix.de, mingo@kernel.org, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, peterz@infradead.org References: <20250319071009.1390984-1-xin@zytor.com> <20250319071009.1390984-4-xin@zytor.com> Content-Language: en-US From: Xin Li Autocrypt: addr=xin@zytor.com; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 3/19/2025 12:17 PM, Brian Gerst wrote: > I'm not sure it's worth fully removing TOP_OF_KERNEL_STACK_PADDING for > 64-bit if it results in needing separate definitions of > task_top_of_stack(). Leaving it at zero is fine. The other changes > are fine though. Let's leave it to x86 maintainers ;-) But to me, TOP_OF_KERNEL_STACK_PADDING no longer makes sense on 64-bit, and it makes it simpler to remove it. On the other side, 32-bit is to be zapped... Thanks! Xin