From patchwork Fri Jul 3 15:36:59 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Catalin Marinas X-Patchwork-Id: 11642055 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 82BC692A for ; Fri, 3 Jul 2020 15:37:43 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 59DE52192A for ; Fri, 3 Jul 2020 15:37:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 59DE52192A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 916988D0075; Fri, 3 Jul 2020 11:37:41 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 87A938D0074; Fri, 3 Jul 2020 11:37:41 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 719D58D0075; Fri, 3 Jul 2020 11:37:41 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0147.hostedemail.com [216.40.44.147]) by kanga.kvack.org (Postfix) with ESMTP id 51DF18D0074 for ; Fri, 3 Jul 2020 11:37:41 -0400 (EDT) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 18B63181AC9BF for ; Fri, 3 Jul 2020 15:37:41 +0000 (UTC) X-FDA: 76997169522.26.pie61_191614026e93 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin26.hostedemail.com (Postfix) with ESMTP id DB8551804A301 for ; Fri, 3 Jul 2020 15:37:40 +0000 (UTC) X-Spam-Summary: 1,0,0,e6146689cca838f1,d41d8cd98f00b204,srs0=nzee=ao=arm.com=catalin.marinas@kernel.org,,RULES_HIT:41:355:379:541:800:960:973:988:989:1260:1311:1314:1345:1359:1431:1437:1515:1534:1541:1711:1730:1747:1777:1792:2198:2199:2393:2559:2562:2731:3138:3139:3140:3141:3142:3353:3865:3866:3867:3868:3870:3871:3874:4321:5007:6261:7903:10004:11026:11232:11658:11914:12114:12296:12297:12438:12517:12519:12555:13069:13180:13229:13311:13357:13894:14096:14181:14384:14394:14721:21080:21230:21451:21627:21740:21795:30003:30012:30051:30054:30070,0,RBL:198.145.29.99:@kernel.org:.lbl8.mailshell.net-62.2.0.100 64.100.201.201;04yfd7z14murjkqukjk1jkxftrgn3opffdut39rth8oxn4w3yxfhawoj87d715k.njh3wozjokwk3fif6mhx3831b3dhqqob94rscckmmz3kurnfj4cbbcij44xco4x.r-lbl8.mailshell.net-223.238.255.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:24,LUA_SUMMARY:none X-HE-Tag: pie61_191614026e93 X-Filterd-Recvd-Size: 3135 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf38.hostedemail.com (Postfix) with ESMTP for ; Fri, 3 Jul 2020 15:37:40 +0000 (UTC) Received: from localhost.localdomain (unknown [95.146.230.158]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8A13B217BA; Fri, 3 Jul 2020 15:37:37 +0000 (UTC) From: Catalin Marinas To: linux-arm-kernel@lists.infradead.org Cc: linux-mm@kvack.org, linux-arch@vger.kernel.org, Will Deacon , Dave P Martin , Vincenzo Frascino , Szabolcs Nagy , Kevin Brodsky , Andrey Konovalov , Peter Collingbourne , Andrew Morton Subject: [PATCH v6 07/26] mm: Preserve the PG_arch_* flags in __split_huge_page_tail() Date: Fri, 3 Jul 2020 16:36:59 +0100 Message-Id: <20200703153718.16973-8-catalin.marinas@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200703153718.16973-1-catalin.marinas@arm.com> References: <20200703153718.16973-1-catalin.marinas@arm.com> MIME-Version: 1.0 X-Rspamd-Queue-Id: DB8551804A301 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: When a huge page is split into normal pages, part of the head page flags are transferred to the tail pages. However, the PG_arch_* flags are not part of the preserved set. PG_arch_1 is currently used by the arch code to handle cache maintenance for user space (either for I-D cache coherency or for D-cache aliases consistent with the kernel mapping). Since splitting a huge page does not change the physical or virtual address of a mapping, additional cache maintenance for the tail pages is unnecessary. Preserving the PG_arch_1 flag from the head page in the tail pages would not break the current use-cases. PG_arch_2 is currently used for arm64 MTE support to mark pages that have valid tags. The absence of such flag causes the arm64 set_pte_at() to clear the tags in order to avoid stale tags exposed to user or the swapping out hooks to ignore the tags. Not preserving PG_arch_2 on huge page splitting leads to tag corruption in the tail pages. To avoid the above and for consistency between the two PG_arch_* flags, preserve both PG_arch_1 and PG_arch_2 in __split_huge_page_tail(). Signed-off-by: Catalin Marinas Cc: Andrew Morton --- Notes: New in v6. mm/huge_memory.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 78c84bee7e29..22b3236a6dd8 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2364,6 +2364,10 @@ static void __split_huge_page_tail(struct page *head, int tail, (1L << PG_workingset) | (1L << PG_locked) | (1L << PG_unevictable) | + (1L << PG_arch_1) | +#ifdef CONFIG_64BIT + (1L << PG_arch_2) | +#endif (1L << PG_dirty))); /* ->mapping in first tail page is compound_mapcount */