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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3857FC43217 for ; Sat, 8 Jan 2022 16:44:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234686AbiAHQom (ORCPT ); Sat, 8 Jan 2022 11:44:42 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:50682 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234713AbiAHQoj (ORCPT ); Sat, 8 Jan 2022 11:44:39 -0500 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 dfw.source.kernel.org (Postfix) with ESMTPS id E43F860DD7 for ; Sat, 8 Jan 2022 16:44:38 +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 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org 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 --- 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); -- 2.33.1