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 0F0CAC04EBF for ; Wed, 5 Dec 2018 18:07:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CD2BD20892 for ; Wed, 5 Dec 2018 18:07:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CD2BD20892 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 S1728264AbeLESHo (ORCPT ); Wed, 5 Dec 2018 13:07:44 -0500 Received: from terminus.zytor.com ([198.137.202.136]:37635 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727388AbeLESHo (ORCPT ); Wed, 5 Dec 2018 13:07:44 -0500 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id wB5I7KIT1375733 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Wed, 5 Dec 2018 10:07:20 -0800 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id wB5I7K7i1375730; Wed, 5 Dec 2018 10:07:20 -0800 Date: Wed, 5 Dec 2018 10:07:20 -0800 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Dan Williams Message-ID: Cc: dave.hansen@linux.intel.com, linux-kernel@vger.kernel.org, dan.j.williams@intel.com, torvalds@linux-foundation.org, stable@vger.kernel.org, mingo@kernel.org, bp@alien8.de, luto@kernel.org, bigeasy@linutronix.de, peterz@infradead.org, riel@surriel.com, tglx@linutronix.de, kirill.shutemov@linux.intel.com, hpa@zytor.com Reply-To: riel@surriel.com, tglx@linutronix.de, kirill.shutemov@linux.intel.com, hpa@zytor.com, bigeasy@linutronix.de, peterz@infradead.org, stable@vger.kernel.org, mingo@kernel.org, bp@alien8.de, luto@kernel.org, dave.hansen@linux.intel.com, linux-kernel@vger.kernel.org, dan.j.williams@intel.com, torvalds@linux-foundation.org In-Reply-To: <154395944713.32119.15611079023837132638.stgit@dwillia2-desk3.amr.corp.intel.com> References: <154395944713.32119.15611079023837132638.stgit@dwillia2-desk3.amr.corp.intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/mm] x86/mm: Drop usage of __flush_tlb_all() in kernel_physical_mapping_init() Git-Commit-ID: ba6f508d0ec4adb09f0a939af6d5e19cdfa8667d 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: ba6f508d0ec4adb09f0a939af6d5e19cdfa8667d Gitweb: https://git.kernel.org/tip/ba6f508d0ec4adb09f0a939af6d5e19cdfa8667d Author: Dan Williams AuthorDate: Tue, 4 Dec 2018 13:37:27 -0800 Committer: Ingo Molnar CommitDate: Wed, 5 Dec 2018 09:03:07 +0100 x86/mm: Drop usage of __flush_tlb_all() in kernel_physical_mapping_init() Commit: f77084d96355 "x86/mm/pat: Disable preemption around __flush_tlb_all()" addressed a case where __flush_tlb_all() is called without preemption being disabled. It also left a warning to catch other cases where preemption is not disabled. That warning triggers for the memory hotplug path which is also used for persistent memory enabling: WARNING: CPU: 35 PID: 911 at ./arch/x86/include/asm/tlbflush.h:460 RIP: 0010:__flush_tlb_all+0x1b/0x3a [..] Call Trace: phys_pud_init+0x29c/0x2bb kernel_physical_mapping_init+0xfc/0x219 init_memory_mapping+0x1a5/0x3b0 arch_add_memory+0x2c/0x50 devm_memremap_pages+0x3aa/0x610 pmem_attach_disk+0x585/0x700 [nd_pmem] Andy wondered why a path that can sleep was using __flush_tlb_all() [1] and Dave confirmed the expectation for TLB flush is for modifying / invalidating existing PTE entries, but not initial population [2]. Drop the usage of __flush_tlb_all() in phys_{p4d,pud,pmd}_init() on the expectation that this path is only ever populating empty entries for the linear map. Note, at linear map teardown time there is a call to the all-cpu flush_tlb_all() to invalidate the removed mappings. [1]: https://lkml.kernel.org/r/9DFD717D-857D-493D-A606-B635D72BAC21@amacapital.net [2]: https://lkml.kernel.org/r/749919a4-cdb1-48a3-adb4-adb81a5fa0b5@intel.com [ mingo: Minor readability edits. ] Suggested-by: Dave Hansen Reported-by: Andy Lutomirski Signed-off-by: Dan Williams Acked-by: Peter Zijlstra (Intel) Acked-by: Kirill A. Shutemov Cc: Cc: Borislav Petkov Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Rik van Riel Cc: Sebastian Andrzej Siewior Cc: Thomas Gleixner Cc: dave.hansen@intel.com Fixes: f77084d96355 ("x86/mm/pat: Disable preemption around __flush_tlb_all()") Link: http://lkml.kernel.org/r/154395944713.32119.15611079023837132638.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Ingo Molnar --- arch/x86/mm/init_64.c | 6 ------ 1 file changed, 6 deletions(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 3e25ac2793ef..484c1b92f078 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -584,7 +584,6 @@ phys_pud_init(pud_t *pud_page, unsigned long paddr, unsigned long paddr_end, paddr_end, page_size_mask, prot); - __flush_tlb_all(); continue; } /* @@ -627,7 +626,6 @@ phys_pud_init(pud_t *pud_page, unsigned long paddr, unsigned long paddr_end, pud_populate_safe(&init_mm, pud, pmd); spin_unlock(&init_mm.page_table_lock); } - __flush_tlb_all(); update_page_count(PG_LEVEL_1G, pages); @@ -668,7 +666,6 @@ phys_p4d_init(p4d_t *p4d_page, unsigned long paddr, unsigned long paddr_end, paddr_last = phys_pud_init(pud, paddr, paddr_end, page_size_mask); - __flush_tlb_all(); continue; } @@ -680,7 +677,6 @@ phys_p4d_init(p4d_t *p4d_page, unsigned long paddr, unsigned long paddr_end, p4d_populate_safe(&init_mm, p4d, pud); spin_unlock(&init_mm.page_table_lock); } - __flush_tlb_all(); return paddr_last; } @@ -733,8 +729,6 @@ kernel_physical_mapping_init(unsigned long paddr_start, if (pgd_changed) sync_global_pgds(vaddr_start, vaddr_end - 1); - __flush_tlb_all(); - return paddr_last; }