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=-10.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 452CAC43387 for ; Mon, 7 Jan 2019 12:41:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 10B2E2183E for ; Mon, 7 Jan 2019 12:41:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1546864887; bh=KrL8UmPt5J8+sWS9r8se95/o9CFkv72Ue9N1F1YSskc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=M29n5yUpL8dleuD7WUPfvkenZkVSrU9jJwedCa0ASpHM4K6+5AzTvNqfDQaEda7wF 5cFIUGpWNJhfvf0kdR58QWEW9oB38TVZiwZJ7WXscaCYva6TF5HHdzkfO0SA2SKWbd 8Jh7DKOZSIKIz71Pj0zzKvOzMgPKrR0k6zpR43q8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728146AbfAGMl0 (ORCPT ); Mon, 7 Jan 2019 07:41:26 -0500 Received: from mail.kernel.org ([198.145.29.99]:56538 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728123AbfAGMlW (ORCPT ); Mon, 7 Jan 2019 07:41:22 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 70A722183F; Mon, 7 Jan 2019 12:41:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1546864881; bh=KrL8UmPt5J8+sWS9r8se95/o9CFkv72Ue9N1F1YSskc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=o2OdJDDtoZ//3sLRL80ImkMKxltW/KJM9RLAnwFqWvknOLWn5bhx5CFGJxOZm6MIj V3L5kGej1zpX6q+mZ0LMgSqsYSfl6NA0D9ADnJTaZndKyrIe8YDaENyRT8tGCuw0Oe CsgAzw8KduJsvvgvc2YHRdeVO02ocRMvOtLhm8sI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dave Hansen , Andy Lutomirski , Dan Williams , "Peter Zijlstra (Intel)" , "Kirill A. Shutemov" , Borislav Petkov , "H. Peter Anvin" , Linus Torvalds , Rik van Riel , Sebastian Andrzej Siewior , Thomas Gleixner , dave.hansen@intel.com, Ingo Molnar Subject: [PATCH 4.20 055/145] x86/mm: Drop usage of __flush_tlb_all() in kernel_physical_mapping_init() Date: Mon, 7 Jan 2019 13:31:32 +0100 Message-Id: <20190107104444.536173566@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190107104437.308206189@linuxfoundation.org> References: <20190107104437.308206189@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.20-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dan Williams commit ba6f508d0ec4adb09f0a939af6d5e19cdfa8667d upstream. 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 Signed-off-by: Greg Kroah-Hartman --- arch/x86/mm/init_64.c | 6 ------ 1 file changed, 6 deletions(-) --- 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 paddr_end, page_size_mask, prot); - __flush_tlb_all(); continue; } /* @@ -627,7 +626,6 @@ phys_pud_init(pud_t *pud_page, unsigned pud_populate(&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 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 p4d_populate(&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 lo if (pgd_changed) sync_global_pgds(vaddr_start, vaddr_end - 1); - __flush_tlb_all(); - return paddr_last; }