From patchwork Thu Oct 22 22:26:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ira Weiny X-Patchwork-Id: 11852065 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 730C16A2 for ; Thu, 22 Oct 2020 22:27:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5A91C2465A for ; Thu, 22 Oct 2020 22:27:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S372801AbgJVW1Q (ORCPT ); Thu, 22 Oct 2020 18:27:16 -0400 Received: from mga09.intel.com ([134.134.136.24]:58278 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S372791AbgJVW1P (ORCPT ); Thu, 22 Oct 2020 18:27:15 -0400 IronPort-SDR: wh7ysvvtPJjKbyKO9tzoNpzzTR1nw1wQNtNYuVU0Un+YDC/WP9pPAuUx7p+Zm0v9HYrk2HsviY nobmHGhldH+A== X-IronPort-AV: E=McAfee;i="6000,8403,9782"; a="167725379" X-IronPort-AV: E=Sophos;i="5.77,404,1596524400"; d="scan'208";a="167725379" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Oct 2020 15:27:13 -0700 IronPort-SDR: PgEON2dSDjhDgwJHX+QIzzPzwQILf6lmaeDrRVmCBuAgdJLZXquxiF992pN86zPkmZ3YD0ncVk vrUzZfm9e8uQ== X-IronPort-AV: E=Sophos;i="5.77,404,1596524400"; d="scan'208";a="524442538" Received: from iweiny-desk2.sc.intel.com (HELO localhost) ([10.3.52.147]) by fmsmga005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Oct 2020 15:27:13 -0700 From: ira.weiny@intel.com To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Andy Lutomirski , Peter Zijlstra Cc: Ira Weiny , x86@kernel.org, Dave Hansen , Dan Williams , Andrew Morton , Fenghua Yu , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Subject: [PATCH 02/10] x86/fpu: Refactor arch_set_user_pkey_access() for PKS support Date: Thu, 22 Oct 2020 15:26:53 -0700 Message-Id: <20201022222701.887660-3-ira.weiny@intel.com> X-Mailer: git-send-email 2.28.0.rc0.12.gb6a658bd00c9 In-Reply-To: <20201022222701.887660-1-ira.weiny@intel.com> References: <20201022222701.887660-1-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; +}