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 08E9D1D8E01 for ; Thu, 7 Nov 2024 23:50:06 +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=1731023408; cv=none; b=iqtPBFm0iAkgX8UGiB2EqNKzD7MszENtMsAsXf5Lh9Oil+NY8tIeSTfBTyTxL1kAxGvvYSyNQmYkmJc66rBzgkf039nrhdosiL8QYZ2XPdFUAkK9aKOVy11xtvRg++G4ZULSl9UhjbAong1kDLtTaPjwzDXqaIZIY2WoaLQKOlI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731023408; c=relaxed/simple; bh=H3FV3rDslQoSdCp5mi94gpGHIG5Z7OkgG69XqEyk/z0=; h=Date:From:To:CC:Subject:In-Reply-To:References:Message-ID: MIME-Version:Content-Type; b=csOrF6RkUrbsGXoH14amUeazKc/RHpZZhfuS4jyWR++J0GvHgSgXAPeL+Y12pZmKlWdmAgDr8JaPtW4Xpq0f0/RIkfHSmd9Q/bppvXxKsJG0giXGi33rHYJHJEy5T75YaV7Vx0cShI+4qfU3SKYgUx7smL3qdBArRQgw1lMX9q4= 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=TNxsKsbl; 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="TNxsKsbl" Received: from [127.0.0.1] ([92.33.209.142]) (authenticated bits=0) by mail.zytor.com (8.18.1/8.17.1) with ESMTPSA id 4A7NnS0K1358141 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Thu, 7 Nov 2024 15:49:30 -0800 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 4A7NnS0K1358141 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2024101701; t=1731023371; bh=6/NZdcb+eDKEKjxoHsmpevhdQTab0euX6eRxoZJgkCI=; h=Date:From:To:CC:Subject:In-Reply-To:References:From; b=TNxsKsbl2bYJHr8Lp9IHi1/5UQNgm/T2lVslLy6DOky83NacHCRET77qbRl9aMUPZ SaA2rU1flLT0h/O3do1YzwSoTrLaawRvmrK+zAIIxP6a+PCMZzUtHC94oop07hGc30 l+BUZrOUcL3whJYklm5hR3IF9JgH9uuoKAql20HpsrcKgDLxBDF7LlvZSuXQ+vBK5D 8G+n2rFfWy6Dmmb7BXkjqMAPMFY+xT+OBg/SbpiP6659nsCH0CGFUn8mulFEYYjdZZ 2gVvShhGHVXExQat5ymc/mBa8Qi8LiuicGS/F9if8lHG2NzCXl0L3ZmooC+tCatYdP 5b72lr9S5QmDQ== Date: Fri, 08 Nov 2024 00:49:22 +0100 From: "H. Peter Anvin" To: Sohil Mehta , Dave Hansen , x86@kernel.org, Borislav Petkov , Dave Hansen CC: Thomas Gleixner , Ingo Molnar , Sean Christopherson , Tony Luck , linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86/cpufeatures: Free up unused feature bits User-Agent: K-9 Mail for Android In-Reply-To: <3492e85d-4aaa-4dd7-9e6a-c8fdc2aa2178@intel.com> References: <20241107233000.2742619-1-sohil.mehta@intel.com> <7ff32a10-1950-434b-8820-bb7c3b408544@intel.com> <3492e85d-4aaa-4dd7-9e6a-c8fdc2aa2178@intel.com> Message-ID: <74338393-4F39-4A04-83B1-BA64CE2D2FDA@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 November 8, 2024 12:44:57 AM GMT+01:00, Sohil Mehta wrote: >On 11/7/2024 3:36 PM, Dave Hansen wrote: >> On 11/7/24 15:30, Sohil Mehta wrote: >>> Linux defined feature bits X86_FEATURE_P3 and X86_FEATURE_P4 are not >>> used anywhere, neither are they visible to userspace=2E >>> commit f31d731e4467 ("x86: use X86_FEATURE_NOPL in alternatives") got >>> rid of the last usage=2E Remove the related mappings and code=2E >>=20 >> Hah, not referenced since 2008! This one seems like a no-brainer=2E > >Thankfully, it wasn't referenced anywhere=2E For a couple of minutes I wa= s >wondering why all family 6 CPUs are marked as Pentium 3 on 32-bit=2E > >> @@ -628,11 +628,6 @@ static void init_intel(struct cpuinfo_x86 *c) >> if (p) >> strcpy(c->x86_model_id, p); >> } > >Here=2E=2E > >> - if (c->x86 =3D=3D 6) >> - set_cpu_cap(c, X86_FEATURE_P3); > Be careful - these bits are used in module strings and so modutils need to= understand them=2E