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 9F4B41B7F4; Mon, 12 Jan 2026 04:02:19 +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=1768190541; cv=none; b=VFAJJrA9Il1DtO5OnAmvLwllVxkWKN544MMnUeBykmwfC8Kv01gMYNPktb4hJsz8gvkVLqNr9feSNpht9BZ158uSa1nS1Z4RyVNpDQdRXCNeudr2CILa6UuGA8bpaqqyGt6VUp6RhWvlPlf2Bq+Pe7hsCEnzD5sgtDJaaJDPBgI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768190541; c=relaxed/simple; bh=XIUG7aYBz2GSjH8VyarZcuEWT6uKwvcqE9seyrdgNqc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=lZS8pUvmTSPC54QPszbaryqqXR9xHYULgAx/h8Rclpw0CMq/Hvzny0V4z4mAnMeM3SjyK5FPVNeQBL/vIbUhKJMzmtJrsh+SvfQmW0HwPaeLZS4/FwrB58ZUovcj1IPdW9dLiOpCa0bPfVU9k+QfIXgdSuoMp3SLB4u0ajWaJk0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com; spf=pass smtp.mailfrom=zytor.com; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b=f3Ek8aRK; arc=none smtp.client-ip=198.137.202.136 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zytor.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b="f3Ek8aRK" Received: from [172.27.2.41] (c-76-133-66-138.hsd1.ca.comcast.net [76.133.66.138]) (authenticated bits=0) by mail.zytor.com (8.18.1/8.17.1) with ESMTPSA id 60C412iW1765885 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Sun, 11 Jan 2026 20:01:06 -0800 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 60C412iW1765885 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2025122301; t=1768190467; bh=SCtgY5YmYEcmGGLDPGoqGQP5fT1Y6ZKUOJ4BIQp+azI=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=f3Ek8aRKzUMVpEn3GXfsPUo3dGYOQ+k7OZt3KjAdPK4TRQJErVik/y0bVSG3SCpCZ zWGlvzOdSV1Bv5OmIYZOo9ZQxYX0xrlOKpsBMP23qQ+onD+qv+Fdm0S4/lQt8s7HuB rPLrqHbtJ9fcA2XgmucGXcD9eCkaQPVzsn2XASBNNMzqmJPOEmw+fwpigsNEBcETfu M9jawAVzveNzZ1JQdzrEKPYO35CDrgrFJArlnFxCsIVR9sKJPwXs4709XPivWaXmVU CgiO6RSNdoqxz9h4jn1dacrUHPR+UXD+d9AElLTNZQDEBLAh0CXj75kOGFfwlfuF67 LYFh7Mtk0om7w== Message-ID: <3f2e8d7c-6029-49ef-8e31-a3eb5efb385b@zytor.com> Date: Sun, 11 Jan 2026 20:01:02 -0800 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: [RFC/RFT PATCH 04/19] x86: Make the 64-bit bzImage always physically relocatable To: Ard Biesheuvel , linux-kernel@vger.kernel.org Cc: x86@kernel.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , Josh Poimboeuf , Peter Zijlstra , Kees Cook , Uros Bizjak , Brian Gerst , linux-hardening@vger.kernel.org References: <20260108092526.28586-21-ardb@kernel.org> <20260108092526.28586-25-ardb@kernel.org> Content-Language: en-US, sv-SE From: "H. Peter Anvin" In-Reply-To: <20260108092526.28586-25-ardb@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 2026-01-08 01:25, Ard Biesheuvel wrote: > On x86_64, the physical placement of the kernel is independent from its > mapping in the 'High Kernel Mapping' range. This means that even a > position dependent kernel built without boot-time relocation support can > run from any suitably aligned physical address, and there is no need to > make this behavior dependent on whether or not the kernel is virtually > relocatable. > > On i386, the situation is different, given that the physical and virtual > load offsets must be equal, and so only a relocatable kernel can be > loaded at a physical address that deviates from its build-time default. > > Clarify this in Kconfig and in the code, and advertise the 64-bit > bzImage as loadable at any physical offset regardless of whether > CONFIG_RELOCATABLE is set. In practice, this makes little difference, > given that it defaults to 'y' and is a prerequisite for EFI_STUB and > RANDOMIZE_BASE, but it will help with some future refactoring of the > relocation code. > I don't see any reason to support non-relocatable kernels anymore. In fact, in a patchset I am working on I have already removed it. -hpa