From patchwork Wed Feb 3 22:58:58 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu-cheng Yu X-Patchwork-Id: 12065679 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 3C325C433E6 for ; Wed, 3 Feb 2021 22:59:47 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id CD8DC64F4D for ; Wed, 3 Feb 2021 22:59:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CD8DC64F4D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 1A0376B008A; Wed, 3 Feb 2021 17:59:44 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 063A26B0089; Wed, 3 Feb 2021 17:59:43 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D7FC58D0001; Wed, 3 Feb 2021 17:59:43 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0087.hostedemail.com [216.40.44.87]) by kanga.kvack.org (Postfix) with ESMTP id A97BA6B0088 for ; Wed, 3 Feb 2021 17:59:43 -0500 (EST) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 6B908181AEF15 for ; Wed, 3 Feb 2021 22:59:43 +0000 (UTC) X-FDA: 77778475446.02.wine04_2510fc7275d7 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin02.hostedemail.com (Postfix) with ESMTP id 5392110097AA2 for ; Wed, 3 Feb 2021 22:59:43 +0000 (UTC) X-HE-Tag: wine04_2510fc7275d7 X-Filterd-Recvd-Size: 5288 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by imf15.hostedemail.com (Postfix) with ESMTP for ; Wed, 3 Feb 2021 22:59:42 +0000 (UTC) IronPort-SDR: YH4sHgCpjSZZBHqOAGU8uJa43euOEZ9IiSuWvb+xABk+ryBeRS+/nIvAlY18Sw7+ghOKc7h8g/ G/uRkjaq4BRQ== X-IronPort-AV: E=McAfee;i="6000,8403,9884"; a="160892368" X-IronPort-AV: E=Sophos;i="5.79,399,1602572400"; d="scan'208";a="160892368" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Feb 2021 14:59:39 -0800 IronPort-SDR: czzSuLwtyAxzTcVcOyb4DmlUjQkIlpUzty7p7mNdWDkaZ1oig7HSCrOlhEt2JTcL2YwvAW55oj qQU2oZvvrurg== X-IronPort-AV: E=Sophos;i="5.79,399,1602572400"; d="scan'208";a="392697960" Received: from yyu32-desk.sc.intel.com ([143.183.136.146]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Feb 2021 14:59:39 -0800 From: Yu-cheng Yu To: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , Weijiang Yang , Pengfei Xu Cc: Yu-cheng Yu Subject: [PATCH v19 3/7] x86/cet/ibt: Handle signals for Indirect Branch Tracking Date: Wed, 3 Feb 2021 14:58:58 -0800 Message-Id: <20210203225902.479-4-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20210203225902.479-1-yu-cheng.yu@intel.com> References: <20210203225902.479-1-yu-cheng.yu@intel.com> MIME-Version: 1.0 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: When an indirect CALL/JMP instruction is executed and before it reaches the target, it is in 'WAIT_ENDBR' status, which can be read from MSR_IA32_U_CET. The status is part of a task's status before a signal is raised and preserved in the signal frame. It is restored for sigreturn. IBT state machine is described in Intel SDM Vol. 1, Sec. 18.3. Signed-off-by: Yu-cheng Yu Reviewed-by: Kees Cook --- arch/x86/kernel/cet.c | 27 +++++++++++++++++++++++++-- arch/x86/kernel/fpu/signal.c | 8 +++++--- 2 files changed, 30 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/cet.c b/arch/x86/kernel/cet.c index fff0b35ed0d9..68d602aecb1c 100644 --- a/arch/x86/kernel/cet.c +++ b/arch/x86/kernel/cet.c @@ -295,6 +295,13 @@ void cet_restore_signal(struct sc_ext *sc_ext) msr_val |= CET_SHSTK_EN; } + if (cet->ibt_enabled) { + msr_val |= (CET_ENDBR_EN | CET_NO_TRACK_EN); + + if (sc_ext->wait_endbr) + msr_val |= CET_WAIT_ENDBR; + } + if (test_thread_flag(TIF_NEED_FPU_LOAD)) cet_user_state->user_cet = msr_val; else @@ -335,9 +342,25 @@ int cet_setup_signal(bool ia32, unsigned long rstor_addr, struct sc_ext *sc_ext) sc_ext->ssp = new_ssp; } - if (ssp) { + if (ssp || cet->ibt_enabled) { + start_update_msrs(); - wrmsrl(MSR_IA32_PL3_SSP, ssp); + + if (ssp) + wrmsrl(MSR_IA32_PL3_SSP, ssp); + + if (cet->ibt_enabled) { + u64 r; + + rdmsrl(MSR_IA32_U_CET, r); + + if (r & CET_WAIT_ENDBR) { + sc_ext->wait_endbr = 1; + r &= ~CET_WAIT_ENDBR; + wrmsrl(MSR_IA32_U_CET, r); + } + } + end_update_msrs(); } diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index 270e4649f435..b914d74c8ba6 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -57,7 +57,8 @@ int save_cet_to_sigframe(int ia32, void __user *fp, unsigned long restorer) { int err = 0; - if (!current->thread.cet.shstk_size) + if (!current->thread.cet.shstk_size && + !current->thread.cet.ibt_enabled) return 0; if (fp) { @@ -89,7 +90,8 @@ static int get_cet_from_sigframe(int ia32, void __user *fp, struct sc_ext *ext) memset(ext, 0, sizeof(*ext)); - if (!current->thread.cet.shstk_size) + if (!current->thread.cet.shstk_size && + !current->thread.cet.ibt_enabled) return 0; if (fp) { @@ -577,7 +579,7 @@ static unsigned long fpu__alloc_sigcontext_ext(unsigned long sp) * sigcontext_ext is at: fpu + fpu_user_xstate_size + * FP_XSTATE_MAGIC2_SIZE, then aligned to 8. */ - if (cet->shstk_size) + if (cet->shstk_size || cet->ibt_enabled) sp -= (sizeof(struct sc_ext) + 8); return sp;