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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 E2B9DECDE5F for ; Thu, 19 Jul 2018 23:37:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 957F620684 for ; Thu, 19 Jul 2018 23:37:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 957F620684 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zytor.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731404AbeGTAXO (ORCPT ); Thu, 19 Jul 2018 20:23:14 -0400 Received: from terminus.zytor.com ([198.137.202.136]:37381 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730505AbeGTAXO (ORCPT ); Thu, 19 Jul 2018 20:23:14 -0400 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id w6JNampL2454507 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Thu, 19 Jul 2018 16:36:48 -0700 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id w6JNam8H2454504; Thu, 19 Jul 2018 16:36:48 -0700 Date: Thu, 19 Jul 2018 16:36:48 -0700 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Joerg Roedel Message-ID: Cc: jpoimboe@redhat.com, dave.hansen@intel.com, dvlasenk@redhat.com, peterz@infradead.org, torvalds@linux-foundation.org, brgerst@gmail.com, llong@redhat.com, dhgutteridge@sympatico.ca, jgross@suse.com, pavel@ucw.cz, boris.ostrovsky@oracle.com, gregkh@linuxfoundation.org, tglx@linutronix.de, hpa@zytor.com, aarcange@redhat.com, eduval@amazon.com, bp@alien8.de, jroedel@suse.de, mingo@kernel.org, jkosina@suse.cz, will.deacon@arm.com, David.Laight@aculab.com, linux-kernel@vger.kernel.org, luto@kernel.org Reply-To: David.Laight@aculab.com, will.deacon@arm.com, luto@kernel.org, linux-kernel@vger.kernel.org, eduval@amazon.com, jkosina@suse.cz, mingo@kernel.org, bp@alien8.de, jroedel@suse.de, hpa@zytor.com, aarcange@redhat.com, gregkh@linuxfoundation.org, tglx@linutronix.de, boris.ostrovsky@oracle.com, dhgutteridge@sympatico.ca, llong@redhat.com, brgerst@gmail.com, pavel@ucw.cz, jgross@suse.com, torvalds@linux-foundation.org, dvlasenk@redhat.com, peterz@infradead.org, dave.hansen@intel.com, jpoimboe@redhat.com In-Reply-To: <1531906876-13451-36-git-send-email-joro@8bytes.org> References: <1531906876-13451-36-git-send-email-joro@8bytes.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/pti] x86/ldt: Split out sanity check in map_ldt_struct() Git-Commit-ID: 9bae3197e15dd5e03ce8e237db6fe4486b08a775 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 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 9bae3197e15dd5e03ce8e237db6fe4486b08a775 Gitweb: https://git.kernel.org/tip/9bae3197e15dd5e03ce8e237db6fe4486b08a775 Author: Joerg Roedel AuthorDate: Wed, 18 Jul 2018 11:41:12 +0200 Committer: Thomas Gleixner CommitDate: Fri, 20 Jul 2018 01:11:47 +0200 x86/ldt: Split out sanity check in map_ldt_struct() This splits out the mapping sanity check and the actual mapping of the LDT to user-space from the map_ldt_struct() function in a way so that it is re-usable for PAE paging. Signed-off-by: Joerg Roedel Signed-off-by: Thomas Gleixner Tested-by: Pavel Machek Cc: "H . Peter Anvin" Cc: linux-mm@kvack.org Cc: Linus Torvalds Cc: Andy Lutomirski Cc: Dave Hansen Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Peter Zijlstra Cc: Borislav Petkov Cc: Jiri Kosina Cc: Boris Ostrovsky Cc: Brian Gerst Cc: David Laight Cc: Denys Vlasenko Cc: Eduardo Valentin Cc: Greg KH Cc: Will Deacon Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: hughd@google.com Cc: keescook@google.com Cc: Andrea Arcangeli Cc: Waiman Long Cc: "David H . Gutteridge" Cc: joro@8bytes.org Link: https://lkml.kernel.org/r/1531906876-13451-36-git-send-email-joro@8bytes.org --- arch/x86/kernel/ldt.c | 82 ++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 58 insertions(+), 24 deletions(-) diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c index e921b3d494d5..69af9a0d57b7 100644 --- a/arch/x86/kernel/ldt.c +++ b/arch/x86/kernel/ldt.c @@ -100,6 +100,49 @@ static struct ldt_struct *alloc_ldt_struct(unsigned int num_entries) return new_ldt; } +#ifdef CONFIG_PAGE_TABLE_ISOLATION + +static void do_sanity_check(struct mm_struct *mm, + bool had_kernel_mapping, + bool had_user_mapping) +{ + if (mm->context.ldt) { + /* + * We already had an LDT. The top-level entry should already + * have been allocated and synchronized with the usermode + * tables. + */ + WARN_ON(!had_kernel_mapping); + if (static_cpu_has(X86_FEATURE_PTI)) + WARN_ON(!had_user_mapping); + } else { + /* + * This is the first time we're mapping an LDT for this process. + * Sync the pgd to the usermode tables. + */ + WARN_ON(had_kernel_mapping); + if (static_cpu_has(X86_FEATURE_PTI)) + WARN_ON(had_user_mapping); + } +} + +static void map_ldt_struct_to_user(struct mm_struct *mm) +{ + pgd_t *pgd = pgd_offset(mm, LDT_BASE_ADDR); + + if (static_cpu_has(X86_FEATURE_PTI) && !mm->context.ldt) + set_pgd(kernel_to_user_pgdp(pgd), *pgd); +} + +static void sanity_check_ldt_mapping(struct mm_struct *mm) +{ + pgd_t *pgd = pgd_offset(mm, LDT_BASE_ADDR); + bool had_kernel = (pgd->pgd != 0); + bool had_user = (kernel_to_user_pgdp(pgd)->pgd != 0); + + do_sanity_check(mm, had_kernel, had_user); +} + /* * If PTI is enabled, this maps the LDT into the kernelmode and * usermode tables for the given mm. @@ -115,9 +158,8 @@ static struct ldt_struct *alloc_ldt_struct(unsigned int num_entries) static int map_ldt_struct(struct mm_struct *mm, struct ldt_struct *ldt, int slot) { -#ifdef CONFIG_PAGE_TABLE_ISOLATION - bool is_vmalloc, had_top_level_entry; unsigned long va; + bool is_vmalloc; spinlock_t *ptl; pgd_t *pgd; int i; @@ -131,13 +173,15 @@ map_ldt_struct(struct mm_struct *mm, struct ldt_struct *ldt, int slot) */ WARN_ON(ldt->slot != -1); + /* Check if the current mappings are sane */ + sanity_check_ldt_mapping(mm); + /* * Did we already have the top level entry allocated? We can't * use pgd_none() for this because it doens't do anything on * 4-level page table kernels. */ pgd = pgd_offset(mm, LDT_BASE_ADDR); - had_top_level_entry = (pgd->pgd != 0); is_vmalloc = is_vmalloc_addr(ldt->entries); @@ -172,35 +216,25 @@ map_ldt_struct(struct mm_struct *mm, struct ldt_struct *ldt, int slot) pte_unmap_unlock(ptep, ptl); } - if (mm->context.ldt) { - /* - * We already had an LDT. The top-level entry should already - * have been allocated and synchronized with the usermode - * tables. - */ - WARN_ON(!had_top_level_entry); - if (static_cpu_has(X86_FEATURE_PTI)) - WARN_ON(!kernel_to_user_pgdp(pgd)->pgd); - } else { - /* - * This is the first time we're mapping an LDT for this process. - * Sync the pgd to the usermode tables. - */ - WARN_ON(had_top_level_entry); - if (static_cpu_has(X86_FEATURE_PTI)) { - WARN_ON(kernel_to_user_pgdp(pgd)->pgd); - set_pgd(kernel_to_user_pgdp(pgd), *pgd); - } - } + /* Propagate LDT mapping to the user page-table */ + map_ldt_struct_to_user(mm); va = (unsigned long)ldt_slot_va(slot); flush_tlb_mm_range(mm, va, va + LDT_SLOT_STRIDE, 0); ldt->slot = slot; -#endif return 0; } +#else /* !CONFIG_PAGE_TABLE_ISOLATION */ + +static int +map_ldt_struct(struct mm_struct *mm, struct ldt_struct *ldt, int slot) +{ + return 0; +} +#endif /* CONFIG_PAGE_TABLE_ISOLATION */ + static void free_ldt_pgtables(struct mm_struct *mm) { #ifdef CONFIG_PAGE_TABLE_ISOLATION