From patchwork Fri Nov 6 23:29:00 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ira Weiny X-Patchwork-Id: 321562 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=-12.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 79322C4741F for ; Fri, 6 Nov 2020 23:29:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 36FA921556 for ; Fri, 6 Nov 2020 23:29:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728766AbgKFX3Z (ORCPT ); Fri, 6 Nov 2020 18:29:25 -0500 Received: from mga12.intel.com ([192.55.52.136]:55504 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728220AbgKFX3Z (ORCPT ); Fri, 6 Nov 2020 18:29:25 -0500 IronPort-SDR: as/5zFG6huIOUo21dE1SihoE0Cyb3X1Bj4kBPiWMGtA8n6NIK6lmZRQEE2EdZuCwasnaUJa8vq O0t75kCctF6A== X-IronPort-AV: E=McAfee;i="6000,8403,9797"; a="148893598" X-IronPort-AV: E=Sophos;i="5.77,457,1596524400"; d="scan'208";a="148893598" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Nov 2020 15:29:25 -0800 IronPort-SDR: rbUZpwuvk6xYCkoYTkH1Bt7ETdx8XmgGvmGGIOdL7uYGh08RC67YOXBkNPJElhbQggJOK0KJwk uJGPtviVWExw== X-IronPort-AV: E=Sophos;i="5.77,457,1596524400"; d="scan'208";a="354907170" Received: from iweiny-desk2.sc.intel.com (HELO localhost) ([10.3.52.147]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Nov 2020 15:29:24 -0800 From: ira.weiny@intel.com To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Andy Lutomirski , Peter Zijlstra , Dave Hansen Cc: Ira Weiny , x86@kernel.org, linux-kernel@vger.kernel.org, Andrew Morton , Fenghua Yu , linux-doc@vger.kernel.org, linux-nvdimm@lists.01.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, Dan Williams , Greg KH Subject: [PATCH V3 02/10] x86/fpu: Refactor arch_set_user_pkey_access() for PKS support Date: Fri, 6 Nov 2020 15:29:00 -0800 Message-Id: <20201106232908.364581-3-ira.weiny@intel.com> X-Mailer: git-send-email 2.28.0.rc0.12.gb6a658bd00c9 In-Reply-To: <20201106232908.364581-1-ira.weiny@intel.com> References: <20201106232908.364581-1-ira.weiny@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org From: Ira Weiny Define a helper, update_pkey_val(), which will be used to support both Protection Key User (PKU) and the new Protection Key for Supervisor (PKS) in subsequent patches. Co-developed-by: Peter Zijlstra Signed-off-by: Peter Zijlstra Signed-off-by: Ira Weiny --- Changes from RFC V3: Per Dave Hansen Update and add comments per Dave's review Per Peter Correct attribution --- arch/x86/include/asm/pkeys.h | 2 ++ arch/x86/kernel/fpu/xstate.c | 22 ++++------------------ arch/x86/mm/pkeys.c | 23 +++++++++++++++++++++++ 3 files changed, 29 insertions(+), 18 deletions(-) diff --git a/arch/x86/include/asm/pkeys.h b/arch/x86/include/asm/pkeys.h index f9feba80894b..4526245b03e5 100644 --- a/arch/x86/include/asm/pkeys.h +++ b/arch/x86/include/asm/pkeys.h @@ -136,4 +136,6 @@ static inline int vma_pkey(struct vm_area_struct *vma) return (vma->vm_flags & vma_pkey_mask) >> VM_PKEY_SHIFT; } +u32 update_pkey_val(u32 pk_reg, int pkey, unsigned int flags); + #endif /*_ASM_X86_PKEYS_H */ diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index a99afc70cc0a..a3bca3211eba 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -994,9 +994,7 @@ const void *get_xsave_field_ptr(int xfeature_nr) int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, unsigned long init_val) { - u32 old_pkru; - int pkey_shift = (pkey * PKR_BITS_PER_PKEY); - u32 new_pkru_bits = 0; + u32 pkru; /* * This check implies XSAVE support. OSPKE only gets @@ -1012,21 +1010,9 @@ int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, */ WARN_ON_ONCE(pkey >= arch_max_pkey()); - /* Set the bits we need in PKRU: */ - if (init_val & PKEY_DISABLE_ACCESS) - new_pkru_bits |= PKR_AD_BIT; - if (init_val & PKEY_DISABLE_WRITE) - new_pkru_bits |= PKR_WD_BIT; - - /* Shift the bits in to the correct place in PKRU for pkey: */ - new_pkru_bits <<= pkey_shift; - - /* Get old PKRU and mask off any old bits in place: */ - old_pkru = read_pkru(); - old_pkru &= ~((PKR_AD_BIT|PKR_WD_BIT) << pkey_shift); - - /* Write old part along with new part: */ - write_pkru(old_pkru | new_pkru_bits); + pkru = read_pkru(); + pkru = update_pkey_val(pkru, pkey, init_val); + write_pkru(pkru); return 0; } diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c index f5efb4007e74..d1dfe743e79f 100644 --- a/arch/x86/mm/pkeys.c +++ b/arch/x86/mm/pkeys.c @@ -208,3 +208,26 @@ static __init int setup_init_pkru(char *opt) return 1; } __setup("init_pkru=", setup_init_pkru); + +/* + * Replace disable bits for @pkey with values from @flags + * + * Kernel users use the same flags as user space: + * PKEY_DISABLE_ACCESS + * PKEY_DISABLE_WRITE + */ +u32 update_pkey_val(u32 pk_reg, int pkey, unsigned int flags) +{ + int pkey_shift = pkey * PKR_BITS_PER_PKEY; + + /* Mask out old bit values */ + pk_reg &= ~(((1 << PKR_BITS_PER_PKEY) - 1) << pkey_shift); + + /* Or in new values */ + if (flags & PKEY_DISABLE_ACCESS) + pk_reg |= PKR_AD_BIT << pkey_shift; + if (flags & PKEY_DISABLE_WRITE) + pk_reg |= PKR_WD_BIT << pkey_shift; + + return pk_reg; +}