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 47A46C8D1 for ; Fri, 9 Aug 2024 22:44:36 +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=1723243479; cv=none; b=m2ChlzLkimK0goo8PvweflX/gz06HSLIsyykm4zN0IhDGgZZOnoiGWvxfW4mvDBxSk7KVrXYMZfw5tiU13XxlHQhKFi2jLaqyY/HJK5P6fE1kfSW6Re8f9GjWjugrL722n7JC0t7lFlMGK0oy/SQiqvDOENhjDkN0UOuUXODr3Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723243479; c=relaxed/simple; bh=MemLbZ6E6qzaYcNaXP9numQeCnV/KRNFJ4VRargPByU=; h=Date:From:To:CC:Subject:In-Reply-To:References:Message-ID: MIME-Version:Content-Type; b=pTlhy1OILOlTIBKvwaJnTnp9g4ojaEGrfud7WJ5BAs/oPcRiLY5HMHGrEXohyj+DaiC6LwZhrDVZJGSJWZB5gtiOUYFsgtDLz+rjX4hHqrwWZHUO9+q7e6KcHqoORygrDGHWQ4P5oSTxpRjQCYETcmaqtOsUkQNRuLkAs/J72P0= 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=a6zCSoV9; 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="a6zCSoV9" Received: from [127.0.0.1] ([76.133.66.138]) (authenticated bits=0) by mail.zytor.com (8.17.2/8.17.1) with ESMTPSA id 479Mi0nT1930590 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Fri, 9 Aug 2024 15:44:01 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 479Mi0nT1930590 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2024071601; t=1723243442; bh=MemLbZ6E6qzaYcNaXP9numQeCnV/KRNFJ4VRargPByU=; h=Date:From:To:CC:Subject:In-Reply-To:References:From; b=a6zCSoV9JPqXnNT3LIxo7tCiCNkCAQEcCxt2PVQJFkETeFf2b3b3JsY1Sv+TfFEgB Eu9FSp3Y0yB4/hTgdymcNuBNFM7Bq7bun0umnlwuWcOEJYKs4YNEZl4N3Nz6e6KEDV p0r2RfPyW5ofM67MeQIVFmvjaSNJGZsaDHO0vWmTHwJclSGyTrId/F72lipJ2G58Ix 493Vokhpuw0JL1/rwons4seSVU/gxYxlNRhmMZ0NGUAXe0UxdOYFXQogaMQ0JNUI2u ysFCKXhFztwSDCMo4QB5vzCcKWFaxbBUBQirLDLLFaMImEJhiF9CKLwEle2Qxcb9h9 PPRvGLpKdBcBQ== Date: Fri, 09 Aug 2024 15:43:58 -0700 From: "H. Peter Anvin" To: Xin Li , Nikolay Borisov , linux-kernel@vger.kernel.org CC: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, peterz@infradead.org, andrew.cooper3@citrix.com, seanjc@google.com Subject: =?US-ASCII?Q?Re=3A_=5BPATCH_v1_3/3=5D_x86/entry=3A_Set_FRED_RSP0_on?= =?US-ASCII?Q?_return_to_userspace_instead_of_context_switch?= User-Agent: K-9 Mail for Android In-Reply-To: <34964ea0-dbf5-41a1-82cb-5f677afad23c@zytor.com> References: <20240807054722.682375-1-xin@zytor.com> <20240807054722.682375-4-xin@zytor.com> <34964ea0-dbf5-41a1-82cb-5f677afad23c@zytor.com> Message-ID: <397D7CEC-F743-4155-AB54-DED1D85FADFA@zytor.com> 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-Transfer-Encoding: quoted-printable On August 9, 2024 10:37:08 AM PDT, Xin Li wrote: >On 8/9/2024 3:45 AM, Nikolay Borisov wrote: >>> +#define TIF_LOAD_USER_STATES=C2=A0=C2=A0=C2=A0 30=C2=A0=C2=A0=C2=A0 /= * Load user level states */ >>=20 >> Wouldn't something along the l ines of TIF_LOAD_FRED_RSP be more descri= ptive, or it's expected that this flag can cover more state in the future? > >Sean mentioned TIF_LOAD_FRED_RSP, however we also have FRED SSP0, which >needs to be handled similarly=2E > >And we also want to use it to cover future states=2E It is very likely that there will be additional uses of this beyond FRED= =2E