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 9691FECDE5F for ; Thu, 19 Jul 2018 23:36:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4F00C20684 for ; Thu, 19 Jul 2018 23:36:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4F00C20684 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 S1731259AbeGTAVm (ORCPT ); Thu, 19 Jul 2018 20:21:42 -0400 Received: from terminus.zytor.com ([198.137.202.136]:52347 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730432AbeGTAVl (ORCPT ); Thu, 19 Jul 2018 20:21:41 -0400 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id w6JNZIXJ2454260 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Thu, 19 Jul 2018 16:35:18 -0700 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id w6JNZIeY2454257; Thu, 19 Jul 2018 16:35:18 -0700 Date: Thu, 19 Jul 2018 16:35:18 -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: jgross@suse.com, boris.ostrovsky@oracle.com, dave.hansen@intel.com, pavel@ucw.cz, gregkh@linuxfoundation.org, will.deacon@arm.com, brgerst@gmail.com, tglx@linutronix.de, hpa@zytor.com, luto@kernel.org, jroedel@suse.de, mingo@kernel.org, eduval@amazon.com, jkosina@suse.cz, linux-kernel@vger.kernel.org, llong@redhat.com, torvalds@linux-foundation.org, bp@alien8.de, aarcange@redhat.com, jpoimboe@redhat.com, dhgutteridge@sympatico.ca, peterz@infradead.org, dvlasenk@redhat.com, David.Laight@aculab.com Reply-To: gregkh@linuxfoundation.org, will.deacon@arm.com, brgerst@gmail.com, pavel@ucw.cz, dave.hansen@intel.com, boris.ostrovsky@oracle.com, jgross@suse.com, jroedel@suse.de, luto@kernel.org, tglx@linutronix.de, hpa@zytor.com, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, llong@redhat.com, eduval@amazon.com, jkosina@suse.cz, mingo@kernel.org, David.Laight@aculab.com, dvlasenk@redhat.com, dhgutteridge@sympatico.ca, peterz@infradead.org, jpoimboe@redhat.com, bp@alien8.de, aarcange@redhat.com In-Reply-To: <1531906876-13451-33-git-send-email-joro@8bytes.org> References: <1531906876-13451-33-git-send-email-joro@8bytes.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/pti] x86/pgtable/pae: Use separate kernel PMDs for user page-table Git-Commit-ID: f59dbe9ca6707eb7ffd0e24359085651c2d7df48 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: f59dbe9ca6707eb7ffd0e24359085651c2d7df48 Gitweb: https://git.kernel.org/tip/f59dbe9ca6707eb7ffd0e24359085651c2d7df48 Author: Joerg Roedel AuthorDate: Wed, 18 Jul 2018 11:41:09 +0200 Committer: Thomas Gleixner CommitDate: Fri, 20 Jul 2018 01:11:46 +0200 x86/pgtable/pae: Use separate kernel PMDs for user page-table When PTI is enabled, separate kernel PMDs in the user page-table are required to map the per-process LDT for user-space. 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/1531906876-13451-33-git-send-email-joro@8bytes.org --- arch/x86/mm/pgtable.c | 100 ++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 81 insertions(+), 19 deletions(-) diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index db6fb7740bf7..8e4e63d46d81 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -182,6 +182,14 @@ static void pgd_dtor(pgd_t *pgd) */ #define PREALLOCATED_PMDS UNSHARED_PTRS_PER_PGD +/* + * We allocate separate PMDs for the kernel part of the user page-table + * when PTI is enabled. We need them to map the per-process LDT into the + * user-space page-table. + */ +#define PREALLOCATED_USER_PMDS (static_cpu_has(X86_FEATURE_PTI) ? \ + KERNEL_PGD_PTRS : 0) + void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd) { paravirt_alloc_pmd(mm, __pa(pmd) >> PAGE_SHIFT); @@ -202,14 +210,14 @@ void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd) /* No need to prepopulate any pagetable entries in non-PAE modes. */ #define PREALLOCATED_PMDS 0 - +#define PREALLOCATED_USER_PMDS 0 #endif /* CONFIG_X86_PAE */ -static void free_pmds(struct mm_struct *mm, pmd_t *pmds[]) +static void free_pmds(struct mm_struct *mm, pmd_t *pmds[], int count) { int i; - for(i = 0; i < PREALLOCATED_PMDS; i++) + for (i = 0; i < count; i++) if (pmds[i]) { pgtable_pmd_page_dtor(virt_to_page(pmds[i])); free_page((unsigned long)pmds[i]); @@ -217,7 +225,7 @@ static void free_pmds(struct mm_struct *mm, pmd_t *pmds[]) } } -static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[]) +static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[], int count) { int i; bool failed = false; @@ -226,7 +234,7 @@ static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[]) if (mm == &init_mm) gfp &= ~__GFP_ACCOUNT; - for(i = 0; i < PREALLOCATED_PMDS; i++) { + for (i = 0; i < count; i++) { pmd_t *pmd = (pmd_t *)__get_free_page(gfp); if (!pmd) failed = true; @@ -241,7 +249,7 @@ static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[]) } if (failed) { - free_pmds(mm, pmds); + free_pmds(mm, pmds, count); return -ENOMEM; } @@ -254,23 +262,38 @@ static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[]) * preallocate which never got a corresponding vma will need to be * freed manually. */ +static void mop_up_one_pmd(struct mm_struct *mm, pgd_t *pgdp) +{ + pgd_t pgd = *pgdp; + + if (pgd_val(pgd) != 0) { + pmd_t *pmd = (pmd_t *)pgd_page_vaddr(pgd); + + *pgdp = native_make_pgd(0); + + paravirt_release_pmd(pgd_val(pgd) >> PAGE_SHIFT); + pmd_free(mm, pmd); + mm_dec_nr_pmds(mm); + } +} + static void pgd_mop_up_pmds(struct mm_struct *mm, pgd_t *pgdp) { int i; - for(i = 0; i < PREALLOCATED_PMDS; i++) { - pgd_t pgd = pgdp[i]; + for (i = 0; i < PREALLOCATED_PMDS; i++) + mop_up_one_pmd(mm, &pgdp[i]); - if (pgd_val(pgd) != 0) { - pmd_t *pmd = (pmd_t *)pgd_page_vaddr(pgd); +#ifdef CONFIG_PAGE_TABLE_ISOLATION - pgdp[i] = native_make_pgd(0); + if (!static_cpu_has(X86_FEATURE_PTI)) + return; - paravirt_release_pmd(pgd_val(pgd) >> PAGE_SHIFT); - pmd_free(mm, pmd); - mm_dec_nr_pmds(mm); - } - } + pgdp = kernel_to_user_pgdp(pgdp); + + for (i = 0; i < PREALLOCATED_USER_PMDS; i++) + mop_up_one_pmd(mm, &pgdp[i + KERNEL_PGD_BOUNDARY]); +#endif } static void pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmds[]) @@ -296,6 +319,38 @@ static void pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmds[]) } } +#ifdef CONFIG_PAGE_TABLE_ISOLATION +static void pgd_prepopulate_user_pmd(struct mm_struct *mm, + pgd_t *k_pgd, pmd_t *pmds[]) +{ + pgd_t *s_pgd = kernel_to_user_pgdp(swapper_pg_dir); + pgd_t *u_pgd = kernel_to_user_pgdp(k_pgd); + p4d_t *u_p4d; + pud_t *u_pud; + int i; + + u_p4d = p4d_offset(u_pgd, 0); + u_pud = pud_offset(u_p4d, 0); + + s_pgd += KERNEL_PGD_BOUNDARY; + u_pud += KERNEL_PGD_BOUNDARY; + + for (i = 0; i < PREALLOCATED_USER_PMDS; i++, u_pud++, s_pgd++) { + pmd_t *pmd = pmds[i]; + + memcpy(pmd, (pmd_t *)pgd_page_vaddr(*s_pgd), + sizeof(pmd_t) * PTRS_PER_PMD); + + pud_populate(mm, u_pud, pmd); + } + +} +#else +static void pgd_prepopulate_user_pmd(struct mm_struct *mm, + pgd_t *k_pgd, pmd_t *pmds[]) +{ +} +#endif /* * Xen paravirt assumes pgd table should be in one page. 64 bit kernel also * assumes that pgd should be in one page. @@ -376,6 +431,7 @@ static inline void _pgd_free(pgd_t *pgd) pgd_t *pgd_alloc(struct mm_struct *mm) { pgd_t *pgd; + pmd_t *u_pmds[PREALLOCATED_USER_PMDS]; pmd_t *pmds[PREALLOCATED_PMDS]; pgd = _pgd_alloc(); @@ -385,12 +441,15 @@ pgd_t *pgd_alloc(struct mm_struct *mm) mm->pgd = pgd; - if (preallocate_pmds(mm, pmds) != 0) + if (preallocate_pmds(mm, pmds, PREALLOCATED_PMDS) != 0) goto out_free_pgd; - if (paravirt_pgd_alloc(mm) != 0) + if (preallocate_pmds(mm, u_pmds, PREALLOCATED_USER_PMDS) != 0) goto out_free_pmds; + if (paravirt_pgd_alloc(mm) != 0) + goto out_free_user_pmds; + /* * Make sure that pre-populating the pmds is atomic with * respect to anything walking the pgd_list, so that they @@ -400,13 +459,16 @@ pgd_t *pgd_alloc(struct mm_struct *mm) pgd_ctor(mm, pgd); pgd_prepopulate_pmd(mm, pgd, pmds); + pgd_prepopulate_user_pmd(mm, pgd, u_pmds); spin_unlock(&pgd_lock); return pgd; +out_free_user_pmds: + free_pmds(mm, u_pmds, PREALLOCATED_USER_PMDS); out_free_pmds: - free_pmds(mm, pmds); + free_pmds(mm, pmds, PREALLOCATED_PMDS); out_free_pgd: _pgd_free(pgd); out: