From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932351AbbIBXdr (ORCPT ); Wed, 2 Sep 2015 19:33:47 -0400 Received: from mga09.intel.com ([134.134.136.24]:1322 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754906AbbIBXba (ORCPT ); Wed, 2 Sep 2015 19:31:30 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.17,457,1437462000"; d="scan'208";a="796659446" Subject: [PATCH 09/15] x86, fpu: add helper xfeature_enabled() instead of test_bit() To: dave@sr71.net Cc: dave.hansen@linux.intel.com, mingo@redhat.com, x86@kernel.org, bp@alien8.de, fenghua.yu@intel.com, tim.c.chen@linux.intel.com, linux-kernel@vger.kernel.org From: Dave Hansen Date: Wed, 02 Sep 2015 16:31:29 -0700 References: <20150902233123.3A7E5FB0@viggo.jf.intel.com> In-Reply-To: <20150902233123.3A7E5FB0@viggo.jf.intel.com> Message-Id: <20150902233129.B1534F86@viggo.jf.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dave Hansen We currently use test_bit() in a few places to see if an xfeature is enabled. It ends up being a bit ugly because 'xfeatures_mask' is a u64 and test_bit wants an 'unsigned long' so it requires a cast. The *_bit() functions are also techincally atomic, which we have no need for here. So, remove the test_bit()s and replace with the new xfeature_enabled() helper. This also provides a central place to add a comment about the future need to support 'system xstates'. Signed-off-by: Dave Hansen Cc: Ingo Molnar Cc: x86@kernel.org Cc: Borislav Petkov Cc: Fenghua Yu Cc: Tim Chen Cc: linux-kernel@vger.kernel.org --- b/arch/x86/kernel/fpu/xstate.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff -puN arch/x86/kernel/fpu/xstate.c~use-xfeature_enabled arch/x86/kernel/fpu/xstate.c --- a/arch/x86/kernel/fpu/xstate.c~use-xfeature_enabled 2015-09-02 15:52:54.829114131 -0700 +++ b/arch/x86/kernel/fpu/xstate.c 2015-09-02 16:23:59.357839810 -0700 @@ -226,6 +226,16 @@ static void __init print_xstate_features } /* + * Note that in the future we will likely need a pair of + * functions here: one for user xstates and the other for + * system xstates. For now, they are the same. + */ +static int xfeature_enabled(enum xfeature xfeature) +{ + return !!(xfeatures_mask & (1UL << xfeature)); +} + +/* * This function sets up offsets and sizes of all extended states in * xsave area. This supports both standard format and compacted format * of the xsave aread. @@ -245,7 +255,7 @@ static void __init setup_xstate_comp(voi if (!cpu_has_xsaves) { for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) { - if (test_bit(i, (unsigned long *)&xfeatures_mask)) { + if (xfeature_enabled(i)) { xstate_comp_offsets[i] = xstate_offsets[i]; xstate_comp_sizes[i] = xstate_sizes[i]; } @@ -257,7 +267,7 @@ static void __init setup_xstate_comp(voi FXSAVE_SIZE + XSAVE_HDR_SIZE; for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) { - if (test_bit(i, (unsigned long *)&xfeatures_mask)) + if (xfeature_enabled(i)) xstate_comp_sizes[i] = xstate_sizes[i]; else xstate_comp_sizes[i] = 0; @@ -319,7 +329,7 @@ static unsigned int __init calculate_xst calculated_xstate_size = FXSAVE_SIZE + XSAVE_HDR_SIZE; for (i = FIRST_EXTENDED_XFEATURE; i < 64; i++) { - if (test_bit(i, (unsigned long *)&xfeatures_mask)) { + if (xfeature_enabled(i)) { cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx); calculated_xstate_size += eax; } _