From patchwork Sat Jan 8 16:44:04 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andy Lutomirski X-Patchwork-Id: 12707548 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 E116FC4332F for ; Sat, 8 Jan 2022 16:44:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BCC636B0096; Sat, 8 Jan 2022 11:44:41 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B53AC6B0099; Sat, 8 Jan 2022 11:44:41 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9A7276B0098; Sat, 8 Jan 2022 11:44:41 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0129.hostedemail.com [216.40.44.129]) by kanga.kvack.org (Postfix) with ESMTP id 854FB6B0095 for ; Sat, 8 Jan 2022 11:44:41 -0500 (EST) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 496BB972E4 for ; Sat, 8 Jan 2022 16:44:41 +0000 (UTC) X-FDA: 79007693562.04.45166D0 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf05.hostedemail.com (Postfix) with ESMTP id 861A2100003 for ; Sat, 8 Jan 2022 16:44:40 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 8F85DB80B48; Sat, 8 Jan 2022 16:44:39 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2C9E7C36AE3; Sat, 8 Jan 2022 16:44:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1641660278; bh=9J/1QKkNyuJOe05xU7vGzx3mhn6KDpei2w55Hnz/oT0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UuXs+Y6u3LWdS8m9HaS3ErgC6rn96YsFIWADrWq0raX8asAen+3bktbjqpqKONCiR B7W82gDbT0uZ090lAVwVhIVT9464iiazwOXTfAvs0tiIvL4QYr5G7FgwEQwCO03kDa cmHRsIlwrqIH5GaNrp6J3sX6gjKiU3mvA21NKNPW6KELcsdtJb/C+1Zer4ZDFtuB33 H5gx1/gRGV+FQdnaVoWdjbMEjcD0/MN4sdcznzXTAVwK11055fWS0b2Yv3YUPbS2lO 5+u0OWrOhBnfT1axklI1TvLdlxrjXkZ2Mus4954aj0Pcm/yG7bm8bnSyHdhk8I9ovJ CuFDP2/cXQ7jg== From: Andy Lutomirski To: Andrew Morton , Linux-MM Cc: Nicholas Piggin , Anton Blanchard , Benjamin Herrenschmidt , Paul Mackerras , Randy Dunlap , linux-arch , x86@kernel.org, Rik van Riel , Dave Hansen , Peter Zijlstra , Nadav Amit , Mathieu Desnoyers , Andy Lutomirski , Ard Biesheuvel Subject: [PATCH 19/23] x86/efi: Make efi_enter/leave_mm use the temporary_mm machinery Date: Sat, 8 Jan 2022 08:44:04 -0800 Message-Id: <3efc4cfd1d7c45a32752ced389d6666be15cde56.1641659630.git.luto@kernel.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: References: MIME-Version: 1.0 X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 861A2100003 X-Stat-Signature: ryx6jcauycz7ipzr13w3jws1sxb966mh Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=UuXs+Y6u; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf05.hostedemail.com: domain of luto@kernel.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=luto@kernel.org X-HE-Tag: 1641660280-743891 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: This should be considerably more robust. It's also necessary for optimized for_each_possible_lazymm_cpu() on x86 -- without this patch, EFI calls in lazy context would remove the lazy mm from mm_cpumask(). Cc: Ard Biesheuvel Signed-off-by: Andy Lutomirski Acked-by: Ard Biesheuvel --- arch/x86/platform/efi/efi_64.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index 7515e78ef898..b9a571904363 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -54,7 +54,7 @@ * 0xffff_ffff_0000_0000 and limit EFI VA mapping space to 64G. */ static u64 efi_va = EFI_VA_START; -static struct mm_struct *efi_prev_mm; +static temp_mm_state_t efi_temp_mm_state; /* * We need our own copy of the higher levels of the page tables @@ -461,15 +461,12 @@ void __init efi_dump_pagetable(void) */ void efi_enter_mm(void) { - efi_prev_mm = current->active_mm; - current->active_mm = &efi_mm; - switch_mm(efi_prev_mm, &efi_mm, NULL); + efi_temp_mm_state = use_temporary_mm(&efi_mm); } void efi_leave_mm(void) { - current->active_mm = efi_prev_mm; - switch_mm(&efi_mm, efi_prev_mm, NULL); + unuse_temporary_mm(efi_temp_mm_state); } static DEFINE_SPINLOCK(efi_runtime_lock);