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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 49482C5AD49 for ; Fri, 30 May 2025 14:05:40 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DD4A36B00D2; Fri, 30 May 2025 10:05:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D84E16B0134; Fri, 30 May 2025 10:05:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C4CE06B0136; Fri, 30 May 2025 10:05:39 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id A73FE6B00D2 for ; Fri, 30 May 2025 10:05:39 -0400 (EDT) Received: from smtpin08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 62A3DBCB7C for ; Fri, 30 May 2025 14:05:39 +0000 (UTC) X-FDA: 83499747198.08.F6BF93C Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf26.hostedemail.com (Postfix) with ESMTP id B9571140016 for ; Fri, 30 May 2025 14:05:37 +0000 (UTC) Authentication-Results: imf26.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf26.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1748613937; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=7eGTseOzNJr05Fj1yEUAb0RalC6UtR410oEZsPPsDSM=; b=BXZItl3NMWfcvdggXx576IpW0MaSatR6NX70TtymBUtBaBdE9Pa2dezcKoSQyEpV6pFMY3 g8h15MFeW5hp20cNCG2wQ56cXocisFrhvl0xtx9zTY+3Pam/0Meu9/sLxMOpReUxQNVkDv jVw59YsLZIAC0/VUkvZFtoT1+3fad8w= ARC-Authentication-Results: i=1; imf26.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf26.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1748613937; a=rsa-sha256; cv=none; b=k1uvgP6ikzGUNDPDp1+tjqawKxdavO0zoCxZof3yO7DCXrVBbJh/4Z5EEzmPAm5+Sz+mGd OKqcJGZ1HFZh1NJcmd3TLDnbOBTcCKJpZlW5wiN2v2pfZ1MgnFcZ7kPCcMxDl8uvURGgB9 ANFny0NFTfNVrnZMmXnkoMaMBV5cw6I= Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8076E26AC; Fri, 30 May 2025 07:05:20 -0700 (PDT) Received: from e125769.cambridge.arm.com (e125769.cambridge.arm.com [10.1.196.27]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id EAB693F673; Fri, 30 May 2025 07:05:31 -0700 (PDT) From: Ryan Roberts To: Catalin Marinas , Will Deacon , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , "David S. Miller" , Andreas Larsson , Juergen Gross , Ajay Kaher , Alexey Makhalov , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Boris Ostrovsky , "Aneesh Kumar K.V" , Andrew Morton , Peter Zijlstra , Arnd Bergmann , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Alexei Starovoitov , Andrey Ryabinin Cc: Ryan Roberts , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, virtualization@lists.linux.dev, xen-devel@lists.xenproject.org, linux-mm@kvack.org Subject: [RFC PATCH v1 6/6] Revert "arm64/mm: Permit lazy_mmu_mode to be nested" Date: Fri, 30 May 2025 15:04:44 +0100 Message-ID: <20250530140446.2387131-7-ryan.roberts@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250530140446.2387131-1-ryan.roberts@arm.com> References: <20250530140446.2387131-1-ryan.roberts@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: B9571140016 X-Stat-Signature: 9n59nxc3fz6acfe3ypmbujiw4e7c5ut6 X-Rspam-User: X-HE-Tag: 1748613937-823894 X-HE-Meta: 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 t+VfCRhV GsT82cKF5pUFILnym3FcCOcY9Agq3Ex22Pxe9Nczhy/mdcg22d9Yor8zSIjEPnI8jHVcZJDjwexwnlUgLAJ75xQuox8yMMORGL0jqrJNNurbBt71HMwFUsNi10bb8IC8QOdx5LhZ9gppiWNRzr+uthsHvBFrsSrt8bFD70/piqmFnBZaePkgap685SxUDvOQF2cTdhPXT2NR9zJXquAiWE8VO5yMQEy9QUknuiqT9LpG8uCckALgWnUOdHFu6DYZtVoPzs1ND0IrI4+o9Fjw/xLfljg== 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: List-Subscribe: List-Unsubscribe: Commit 491344301b25 ("arm64/mm: Permit lazy_mmu_mode to be nested") made the arm64 implementation of lazy_mmu_mode tolerant to nesting. But subsequent commits have fixed the core code to ensure that lazy_mmu_mode never gets nested (as originally intended). Therefore we can revert this commit and reinstate the VM_WARN() if nesting is detected in future. Signed-off-by: Ryan Roberts --- arch/arm64/include/asm/pgtable.h | 14 ++------------ 1 file changed, 2 insertions(+), 12 deletions(-) diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index add75dee49f5..dcf0adbeb803 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -83,21 +83,11 @@ static inline void queue_pte_barriers(void) #define __HAVE_ARCH_ENTER_LAZY_MMU_MODE static inline void arch_enter_lazy_mmu_mode(void) { - /* - * lazy_mmu_mode is not supposed to permit nesting. But in practice this - * does happen with CONFIG_DEBUG_PAGEALLOC, where a page allocation - * inside a lazy_mmu_mode section (such as zap_pte_range()) will change - * permissions on the linear map with apply_to_page_range(), which - * re-enters lazy_mmu_mode. So we tolerate nesting in our - * implementation. The first call to arch_leave_lazy_mmu_mode() will - * flush and clear the flag such that the remainder of the work in the - * outer nest behaves as if outside of lazy mmu mode. This is safe and - * keeps tracking simple. - */ - if (in_interrupt()) return; + VM_WARN_ON(test_thread_flag(TIF_LAZY_MMU)); + set_thread_flag(TIF_LAZY_MMU); } -- 2.43.0