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[209.132.180.67]) by mx.google.com with ESMTP id r26si501076pgu.422.2018.04.09.10.22.51; Mon, 09 Apr 2018 10:23:28 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753784AbeDIRRg (ORCPT + 99 others); Mon, 9 Apr 2018 13:17:36 -0400 Received: from terminus.zytor.com ([198.137.202.136]:50569 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752065AbeDIRRe (ORCPT ); Mon, 9 Apr 2018 13:17:34 -0400 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTP id w39HFb9S1894710; Mon, 9 Apr 2018 10:15:37 -0700 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id w39HFbcT1894707; Mon, 9 Apr 2018 10:15:37 -0700 Date: Mon, 9 Apr 2018 10:15:37 -0700 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Dave Hansen Message-ID: Cc: dan.j.williams@intel.com, luto@kernel.org, dave.hansen@linux.intel.com, hpa@zytor.com, torvalds@linux-foundation.org, arjan@linux.intel.com, mingo@kernel.org, keescook@google.com, peterz@infradead.org, dwmw2@infradead.org, bp@alien8.de, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, jpoimboe@redhat.com, tglx@linutronix.de, jgross@suse.com, aarcange@redhat.com, hughd@google.com, namit@vmware.com Reply-To: luto@kernel.org, dave.hansen@linux.intel.com, hpa@zytor.com, dan.j.williams@intel.com, mingo@kernel.org, keescook@google.com, peterz@infradead.org, dwmw2@infradead.org, torvalds@linux-foundation.org, arjan@linux.intel.com, jpoimboe@redhat.com, tglx@linutronix.de, bp@alien8.de, linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org, aarcange@redhat.com, hughd@google.com, namit@vmware.com, jgross@suse.com In-Reply-To: <20180406205515.2977EE7D@viggo.jf.intel.com> References: <20180406205515.2977EE7D@viggo.jf.intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/pti] x86/pti: Enable global pages for shared areas Git-Commit-ID: e0bb456e32505b08e42477714169111fbdbff95b X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Spam-Status: No, score=-2.9 required=5.0 tests=ALL_TRUSTED,BAYES_00 autolearn=ham autolearn_force=no version=3.4.1 X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on terminus.zytor.com Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: e0bb456e32505b08e42477714169111fbdbff95b Gitweb: https://git.kernel.org/tip/e0bb456e32505b08e42477714169111fbdbff95b Author: Dave Hansen AuthorDate: Fri, 6 Apr 2018 13:55:15 -0700 Committer: Ingo Molnar CommitDate: Mon, 9 Apr 2018 18:27:34 +0200 x86/pti: Enable global pages for shared areas The entry/exit text and cpu_entry_area are mapped into userspace and the kernel. But, they are not _PAGE_GLOBAL. This creates unnecessary TLB misses. Add the _PAGE_GLOBAL flag for these areas. Signed-off-by: Dave Hansen Cc: Andrea Arcangeli Cc: Andy Lutomirski Cc: Arjan van de Ven Cc: Borislav Petkov Cc: Dan Williams Cc: David Woodhouse Cc: Greg Kroah-Hartman Cc: Hugh Dickins Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Kees Cook Cc: Linus Torvalds Cc: Nadav Amit Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20180406205515.2977EE7D@viggo.jf.intel.com Signed-off-by: Ingo Molnar --- arch/x86/mm/cpu_entry_area.c | 14 +++++++++++++- arch/x86/mm/pti.c | 23 ++++++++++++++++++++++- 2 files changed, 35 insertions(+), 2 deletions(-) diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c index 476d810639a8..b45f5aaefd74 100644 --- a/arch/x86/mm/cpu_entry_area.c +++ b/arch/x86/mm/cpu_entry_area.c @@ -27,8 +27,20 @@ EXPORT_SYMBOL(get_cpu_entry_area); void cea_set_pte(void *cea_vaddr, phys_addr_t pa, pgprot_t flags) { unsigned long va = (unsigned long) cea_vaddr; + pte_t pte = pfn_pte(pa >> PAGE_SHIFT, flags); - set_pte_vaddr(va, pfn_pte(pa >> PAGE_SHIFT, flags)); + /* + * The cpu_entry_area is shared between the user and kernel + * page tables. All of its ptes can safely be global. + * _PAGE_GLOBAL gets reused to help indicate PROT_NONE for + * non-present PTEs, so be careful not to set it in that + * case to avoid confusion. + */ + if (boot_cpu_has(X86_FEATURE_PGE) && + (pgprot_val(flags) & _PAGE_PRESENT)) + pte = pte_set_flags(pte, _PAGE_GLOBAL); + + set_pte_vaddr(va, pte); } static void __init diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c index 631507f0c198..8082f8b0c10e 100644 --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -299,6 +299,27 @@ pti_clone_pmds(unsigned long start, unsigned long end, pmdval_t clear) if (WARN_ON(!target_pmd)) return; + /* + * Only clone present PMDs. This ensures only setting + * _PAGE_GLOBAL on present PMDs. This should only be + * called on well-known addresses anyway, so a non- + * present PMD would be a surprise. + */ + if (WARN_ON(!(pmd_flags(*pmd) & _PAGE_PRESENT))) + return; + + /* + * Setting 'target_pmd' below creates a mapping in both + * the user and kernel page tables. It is effectively + * global, so set it as global in both copies. Note: + * the X86_FEATURE_PGE check is not _required_ because + * the CPU ignores _PAGE_GLOBAL when PGE is not + * supported. The check keeps consistentency with + * code that only set this bit when supported. + */ + if (boot_cpu_has(X86_FEATURE_PGE)) + *pmd = pmd_set_flags(*pmd, _PAGE_GLOBAL); + /* * Copy the PMD. That is, the kernelmode and usermode * tables will share the last-level page tables of this @@ -348,7 +369,7 @@ static void __init pti_clone_entry_text(void) { pti_clone_pmds((unsigned long) __entry_text_start, (unsigned long) __irqentry_text_end, - _PAGE_RW | _PAGE_GLOBAL); + _PAGE_RW); } /*