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=-12.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,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 BE1CFC64EB4 for ; Fri, 30 Nov 2018 09:58:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 82FFC2146D for ; Fri, 30 Nov 2018 09:58:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 82FFC2146D 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 S1726970AbeK3VHi (ORCPT ); Fri, 30 Nov 2018 16:07:38 -0500 Received: from terminus.zytor.com ([198.137.202.136]:38137 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726499AbeK3VHi (ORCPT ); Fri, 30 Nov 2018 16:07:38 -0500 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id wAU9w5o73261877 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Fri, 30 Nov 2018 01:58:05 -0800 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id wAU9w5Sb3261874; Fri, 30 Nov 2018 01:58:05 -0800 Date: Fri, 30 Nov 2018 01:58:05 -0800 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Sai Praneeth Prakhya Message-ID: Cc: matt@codeblueprint.co.uk, bhsharma@redhat.com, peterz@infradead.org, hdegoede@redhat.com, jonathanh@nvidia.com, sedat.dilek@gmail.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, zhuyifei1999@gmail.com, hpa@zytor.com, joe@perches.com, julien.thierry@arm.com, torvalds@linux-foundation.org, natechancellor@gmail.com, ard.biesheuvel@linaro.org, marc.zyngier@arm.com, dave.hansen@intel.com, bp@alien8.de, luto@kernel.org, sai.praneeth.prakhya@intel.com, mingo@kernel.org, arend.vanspriel@broadcom.com, eric.snowberg@oracle.com Reply-To: luto@kernel.org, marc.zyngier@arm.com, dave.hansen@intel.com, bp@alien8.de, ard.biesheuvel@linaro.org, torvalds@linux-foundation.org, natechancellor@gmail.com, eric.snowberg@oracle.com, arend.vanspriel@broadcom.com, mingo@kernel.org, sai.praneeth.prakhya@intel.com, jonathanh@nvidia.com, peterz@infradead.org, hdegoede@redhat.com, matt@codeblueprint.co.uk, bhsharma@redhat.com, julien.thierry@arm.com, joe@perches.com, sedat.dilek@gmail.com, hpa@zytor.com, tglx@linutronix.de, zhuyifei1999@gmail.com, linux-kernel@vger.kernel.org In-Reply-To: <20181129171230.18699-5-ard.biesheuvel@linaro.org> References: <20181129171230.18699-5-ard.biesheuvel@linaro.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:efi/core] x86/mm/pageattr: Introduce helper function to unmap EFI boot services Git-Commit-ID: 7e0dabd3010d6041ee0a952c1146b2150a11f1be 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: 7e0dabd3010d6041ee0a952c1146b2150a11f1be Gitweb: https://git.kernel.org/tip/7e0dabd3010d6041ee0a952c1146b2150a11f1be Author: Sai Praneeth Prakhya AuthorDate: Thu, 29 Nov 2018 18:12:23 +0100 Committer: Ingo Molnar CommitDate: Fri, 30 Nov 2018 09:10:30 +0100 x86/mm/pageattr: Introduce helper function to unmap EFI boot services Ideally, after kernel assumes control of the platform, firmware shouldn't access EFI boot services code/data regions. But, it's noticed that this is not so true in many x86 platforms. Hence, during boot, kernel reserves EFI boot services code/data regions [1] and maps [2] them to efi_pgd so that call to set_virtual_address_map() doesn't fail. After returning from set_virtual_address_map(), kernel frees the reserved regions [3] but they still remain mapped. Hence, introduce kernel_unmap_pages_in_pgd() which will later be used to unmap EFI boot services code/data regions. While at it modify kernel_map_pages_in_pgd() by: 1. Adding __init modifier because it's always used *only* during boot. 2. Add a warning if it's used after SMP is initialized because it uses __flush_tlb_all() which flushes mappings only on current CPU. Unmapping EFI boot services code/data regions will result in clearing PAGE_PRESENT bit and it shouldn't bother L1TF cases because it's already handled by protnone_mask() at arch/x86/include/asm/pgtable-invert.h. [1] efi_reserve_boot_services() [2] efi_map_region() -> __map_region() -> kernel_map_pages_in_pgd() [3] efi_free_boot_services() Signed-off-by: Sai Praneeth Prakhya Signed-off-by: Ard Biesheuvel Reviewed-by: Thomas Gleixner Cc: Andy Lutomirski Cc: Arend van Spriel Cc: Bhupesh Sharma Cc: Borislav Petkov Cc: Dave Hansen Cc: Eric Snowberg Cc: Hans de Goede Cc: Joe Perches Cc: Jon Hunter Cc: Julien Thierry Cc: Linus Torvalds Cc: Marc Zyngier Cc: Matt Fleming Cc: Nathan Chancellor Cc: Peter Zijlstra Cc: Sedat Dilek Cc: YiFei Zhu Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20181129171230.18699-5-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar --- arch/x86/include/asm/pgtable_types.h | 8 ++++++-- arch/x86/mm/pageattr.c | 40 ++++++++++++++++++++++++++++++++++-- 2 files changed, 44 insertions(+), 4 deletions(-) diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index 106b7d0e2dae..d6ff0bbdb394 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -564,8 +564,12 @@ extern pte_t *lookup_address_in_pgd(pgd_t *pgd, unsigned long address, unsigned int *level); extern pmd_t *lookup_pmd_address(unsigned long address); extern phys_addr_t slow_virt_to_phys(void *__address); -extern int kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address, - unsigned numpages, unsigned long page_flags); +extern int __init kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, + unsigned long address, + unsigned numpages, + unsigned long page_flags); +extern int __init kernel_unmap_pages_in_pgd(pgd_t *pgd, unsigned long address, + unsigned long numpages); #endif /* !__ASSEMBLY__ */ #endif /* _ASM_X86_PGTABLE_DEFS_H */ diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index db7a10082238..bac35001d896 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -2338,8 +2338,8 @@ bool kernel_page_present(struct page *page) #endif /* CONFIG_DEBUG_PAGEALLOC */ -int kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address, - unsigned numpages, unsigned long page_flags) +int __init kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address, + unsigned numpages, unsigned long page_flags) { int retval = -EINVAL; @@ -2353,6 +2353,8 @@ int kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address, .flags = 0, }; + WARN_ONCE(num_online_cpus() > 1, "Don't call after initializing SMP"); + if (!(__supported_pte_mask & _PAGE_NX)) goto out; @@ -2374,6 +2376,40 @@ out: return retval; } +/* + * __flush_tlb_all() flushes mappings only on current CPU and hence this + * function shouldn't be used in an SMP environment. Presently, it's used only + * during boot (way before smp_init()) by EFI subsystem and hence is ok. + */ +int __init kernel_unmap_pages_in_pgd(pgd_t *pgd, unsigned long address, + unsigned long numpages) +{ + int retval; + + /* + * The typical sequence for unmapping is to find a pte through + * lookup_address_in_pgd() (ideally, it should never return NULL because + * the address is already mapped) and change it's protections. As pfn is + * the *target* of a mapping, it's not useful while unmapping. + */ + struct cpa_data cpa = { + .vaddr = &address, + .pfn = 0, + .pgd = pgd, + .numpages = numpages, + .mask_set = __pgprot(0), + .mask_clr = __pgprot(_PAGE_PRESENT | _PAGE_RW), + .flags = 0, + }; + + WARN_ONCE(num_online_cpus() > 1, "Don't call after initializing SMP"); + + retval = __change_page_attr_set_clr(&cpa, 0); + __flush_tlb_all(); + + return retval; +} + /* * The testcases use internal knowledge of the implementation that shouldn't * be exposed to the rest of the kernel. Include these directly here.