From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752620AbaEZQ66 (ORCPT ); Mon, 26 May 2014 12:58:58 -0400 Received: from mga11.intel.com ([192.55.52.93]:20669 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752019AbaEZQ56 (ORCPT ); Mon, 26 May 2014 12:57:58 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.98,914,1392192000"; d="scan'208";a="545122353" From: "Fenghua Yu" To: "H. Peter Anvin" , "Ingo Molnar" , "Thomas Gleixner" , "Asit K Mallick" Cc: "linux-kernel" , "x86" , "Fenghua Yu" Subject: [PATCH 14/15] x86/xsaves: Enable xsaves/xrstors Date: Mon, 26 May 2014 10:01:21 -0700 Message-Id: <1401123682-5384-15-git-send-email-fenghua.yu@intel.com> X-Mailer: git-send-email 1.8.0.1 In-Reply-To: <1401123682-5384-1-git-send-email-fenghua.yu@intel.com> References: <1401123682-5384-1-git-send-email-fenghua.yu@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Fenghua Yu If xsaves/xrstors is enabled, compacted format of xsave area will be used and less memory may be used for context switching per process. Modified optimization implemented in xsaves/xrstors improves performance of saving xstate as well. Signed-off-by: Fenghua Yu --- arch/x86/kernel/xsave.c | 38 ++++++++++++++++++++++++++++++++------ 1 file changed, 32 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c index 8fa7c7d..2e9a77d 100644 --- a/arch/x86/kernel/xsave.c +++ b/arch/x86/kernel/xsave.c @@ -8,6 +8,7 @@ #include #include +#include #include #include #include @@ -24,7 +25,9 @@ u64 pcntxt_mask; struct xsave_struct *init_xstate_buf; static struct _fpx_sw_bytes fx_sw_reserved, fx_sw_reserved_ia32; -static unsigned int *xstate_offsets, *xstate_sizes, xstate_features; +static unsigned int *xstate_offsets, *xstate_sizes; +static unsigned int *xstate_comp_offsets, *xstate_comp_sizes; +static unsigned int xstate_features; /* * If a processor implementation discern that a processor state component is @@ -283,7 +286,7 @@ sanitize_restored_xstate(struct task_struct *tsk, if (use_xsave()) { /* These bits must be zero. */ - xsave_hdr->reserved1[0] = xsave_hdr->reserved1[1] = 0; + memset(xsave_hdr->reserved, 0, 48); /* * Init the state that is not present in the memory @@ -526,6 +529,30 @@ static int __init eager_fpu_setup(char *s) } __setup("eagerfpu=", eager_fpu_setup); + +/* + * Calculate total size of enabled xstates in XCR0/pcntxt_mask. + */ +static void __init init_xstate_size(void) +{ + unsigned int eax, ebx, ecx, edx; + int i; + + if (!cpu_has_xsaves) { + cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx); + xstate_size = ebx; + return; + } + + xstate_size = FXSAVE_SIZE + XSAVE_HDR_SIZE; + for (i = 2; i < 64; i++) { + if (test_bit(i, (unsigned long *)&pcntxt_mask)) { + cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx); + xstate_size += eax; + } + } +} + /* * Enable and initialize the xsave feature. */ @@ -557,8 +584,7 @@ static void __init xstate_enable_boot_cpu(void) /* * Recompute the context size for enabled features */ - cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx); - xstate_size = ebx; + init_xstate_size(); update_regset_xstate_info(xstate_size, pcntxt_mask); prepare_fx_sw_frame(); @@ -578,8 +604,8 @@ static void __init xstate_enable_boot_cpu(void) } } - pr_info("enabled xstate_bv 0x%llx, cntxt size 0x%x\n", - pcntxt_mask, xstate_size); + pr_info("enabled xstate_bv 0x%llx, cntxt size 0x%x using %s\n", + pcntxt_mask, xstate_size, cpu_has_xsaves ? "xsaves" : "xsave"); } /* -- 1.8.1.2