From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 269E0C433E1 for ; Fri, 3 Jul 2020 12:54:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0480520B80 for ; Fri, 3 Jul 2020 12:54:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726802AbgGCMx7 (ORCPT ); Fri, 3 Jul 2020 08:53:59 -0400 Received: from mga18.intel.com ([134.134.136.126]:25755 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726741AbgGCMxx (ORCPT ); Fri, 3 Jul 2020 08:53:53 -0400 IronPort-SDR: 9P+hxO+SaNzmMYmkgFgAm2cSjUItUJt3kZjkrUnKqDPE/2ghjCZLjILZgVi+gr3PxueGItkbxm ErHcT7XNe1VA== X-IronPort-AV: E=McAfee;i="6000,8403,9670"; a="134598411" X-IronPort-AV: E=Sophos;i="5.75,308,1589266800"; d="scan'208";a="134598411" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Jul 2020 05:53:51 -0700 IronPort-SDR: 4nSvdjJ0OCK73zxctKdj4UYotqZzq6+BebSRX4QXTTVVGnJWzwZK1pLaVYX+0k0MLWtM/vPx2b lCvv9VEO7ZJg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,308,1589266800"; d="scan'208";a="265964059" Received: from otc-lr-04.jf.intel.com ([10.54.39.143]) by fmsmga007.fm.intel.com with ESMTP; 03 Jul 2020 05:53:50 -0700 From: kan.liang@linux.intel.com To: peterz@infradead.org, mingo@redhat.com, acme@kernel.org, tglx@linutronix.de, bp@alien8.de, x86@kernel.org, linux-kernel@vger.kernel.org Cc: mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@redhat.com, namhyung@kernel.org, dave.hansen@intel.com, yu-cheng.yu@intel.com, bigeasy@linutronix.de, gorcunov@gmail.com, hpa@zytor.com, alexey.budankov@linux.intel.com, eranian@google.com, ak@linux.intel.com, like.xu@linux.intel.com, yao.jin@linux.intel.com, wei.w.wang@intel.com, Kan Liang Subject: [PATCH V3 21/23] x86/fpu/xstate: Add helpers for LBR dynamic supervisor feature Date: Fri, 3 Jul 2020 05:49:27 -0700 Message-Id: <1593780569-62993-22-git-send-email-kan.liang@linux.intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1593780569-62993-1-git-send-email-kan.liang@linux.intel.com> References: <1593780569-62993-1-git-send-email-kan.liang@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kan Liang The perf subsystem will only need to save/restore the LBR state. However, the existing helpers save all supported supervisor states to a kernel buffer, which will be unnecessary. Two helpers are introduced to only save/restore requested dynamic supervisor states. The supervisor features in XFEATURE_MASK_SUPERVISOR_SUPPORTED and XFEATURE_MASK_SUPERVISOR_UNSUPPORTED mask cannot be saved/restored using these helpers. The helpers will be used in the following patch. Reviewed-by: Dave Hansen Signed-off-by: Kan Liang --- arch/x86/include/asm/fpu/xstate.h | 3 ++ arch/x86/kernel/fpu/xstate.c | 72 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 75 insertions(+) diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h index 040c4d4..c029fce 100644 --- a/arch/x86/include/asm/fpu/xstate.h +++ b/arch/x86/include/asm/fpu/xstate.h @@ -106,6 +106,9 @@ int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned i int copy_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf); int copy_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf); void copy_supervisor_to_kernel(struct xregs_state *xsave); +void copy_dynamic_supervisor_to_kernel(struct xregs_state *xstate, u64 mask); +void copy_kernel_to_dynamic_supervisor(struct xregs_state *xstate, u64 mask); + /* Validate an xstate header supplied by userspace (ptrace or sigreturn) */ int validate_user_xstate_header(const struct xstate_header *hdr); diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index dcf0624..b0c22b7 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -1361,6 +1361,78 @@ void copy_supervisor_to_kernel(struct xregs_state *xstate) } } +/** + * copy_dynamic_supervisor_to_kernel() - Save dynamic supervisor states to + * an xsave area + * @xstate: A pointer to an xsave area + * @mask: Represent the dynamic supervisor features saved into the xsave area + * + * Only the dynamic supervisor states sets in the mask are saved into the xsave + * area (See the comment in XFEATURE_MASK_DYNAMIC for the details of dynamic + * supervisor feature). Besides the dynamic supervisor states, the legacy + * region and XSAVE header are also saved into the xsave area. The supervisor + * features in the XFEATURE_MASK_SUPERVISOR_SUPPORTED and + * XFEATURE_MASK_SUPERVISOR_UNSUPPORTED are not saved. + * + * The xsave area must be 64-bytes aligned. + */ +void copy_dynamic_supervisor_to_kernel(struct xregs_state *xstate, u64 mask) +{ + u64 dynamic_mask = xfeatures_mask_dynamic() & mask; + u32 lmask, hmask; + int err; + + if (WARN_ON_FPU(!boot_cpu_has(X86_FEATURE_XSAVES))) + return; + + if (WARN_ON_FPU(!dynamic_mask)) + return; + + lmask = dynamic_mask; + hmask = dynamic_mask >> 32; + + XSTATE_OP(XSAVES, xstate, lmask, hmask, err); + + /* Should never fault when copying to a kernel buffer */ + WARN_ON_FPU(err); +} + +/** + * copy_kernel_to_dynamic_supervisor() - Restore dynamic supervisor states from + * an xsave area + * @xstate: A pointer to an xsave area + * @mask: Represent the dynamic supervisor features restored from the xsave area + * + * Only the dynamic supervisor states sets in the mask are restored from the + * xsave area (See the comment in XFEATURE_MASK_DYNAMIC for the details of + * dynamic supervisor feature). Besides the dynamic supervisor states, the + * legacy region and XSAVE header are also restored from the xsave area. The + * supervisor features in the XFEATURE_MASK_SUPERVISOR_SUPPORTED and + * XFEATURE_MASK_SUPERVISOR_UNSUPPORTED are not restored. + * + * The xsave area must be 64-bytes aligned. + */ +void copy_kernel_to_dynamic_supervisor(struct xregs_state *xstate, u64 mask) +{ + u64 dynamic_mask = xfeatures_mask_dynamic() & mask; + u32 lmask, hmask; + int err; + + if (WARN_ON_FPU(!boot_cpu_has(X86_FEATURE_XSAVES))) + return; + + if (WARN_ON_FPU(!dynamic_mask)) + return; + + lmask = dynamic_mask; + hmask = dynamic_mask >> 32; + + XSTATE_OP(XRSTORS, xstate, lmask, hmask, err); + + /* Should never fault when copying from a kernel buffer */ + WARN_ON_FPU(err); +} + #ifdef CONFIG_PROC_PID_ARCH_STATUS /* * Report the amount of time elapsed in millisecond since last AVX512 -- 2.7.4