From patchwork Tue Feb 22 15:00:23 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 12755288 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 35452C433F5 for ; Tue, 22 Feb 2022 15:02:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233182AbiBVPCW (ORCPT ); Tue, 22 Feb 2022 10:02:22 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48338 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233218AbiBVPCM (ORCPT ); Tue, 22 Feb 2022 10:02:12 -0500 Received: from pegase2.c-s.fr (pegase2.c-s.fr [93.17.235.10]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8415515DB36; Tue, 22 Feb 2022 07:00:46 -0800 (PST) Received: from localhost (mailhub3.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4K32RG2FNsz9sSr; Tue, 22 Feb 2022 16:00:42 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase2.c-s.fr ([172.26.127.65]) by localhost (pegase2.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Jkdtpc5Rx5nb; Tue, 22 Feb 2022 16:00:42 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase2.c-s.fr (Postfix) with ESMTP id 4K32RF2YWLz9sSP; Tue, 22 Feb 2022 16:00:41 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 476688B764; Tue, 22 Feb 2022 16:00:41 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id rf5u4YC7nEWc; Tue, 22 Feb 2022 16:00:41 +0100 (CET) Received: from PO20335.IDSI0.si.c-s.fr (unknown [192.168.7.78]) by messagerie.si.c-s.fr (Postfix) with ESMTP id BD5EA8B778; Tue, 22 Feb 2022 16:00:40 +0100 (CET) Received: from PO20335.IDSI0.si.c-s.fr (localhost [127.0.0.1]) by PO20335.IDSI0.si.c-s.fr (8.17.1/8.16.1) with ESMTPS id 21MF0b6D1087085 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Tue, 22 Feb 2022 16:00:37 +0100 Received: (from chleroy@localhost) by PO20335.IDSI0.si.c-s.fr (8.17.1/8.17.1/Submit) id 21MF0ZDD1087083; Tue, 22 Feb 2022 16:00:35 +0100 X-Authentication-Warning: PO20335.IDSI0.si.c-s.fr: chleroy set sender to christophe.leroy@csgroup.eu using -f From: Christophe Leroy To: Luis Chamberlain , Aaron Tomlin Cc: Christophe Leroy , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kgdb-bugreport@lists.sourceforge.net, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-modules@vger.kernel.org, Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras Subject: [PATCH v5 6/6] powerpc: Select ARCH_WANTS_MODULES_DATA_IN_VMALLOC on book3s/32 and 8xx Date: Tue, 22 Feb 2022 16:00:23 +0100 Message-Id: X-Mailer: git-send-email 2.34.1 In-Reply-To: References: MIME-Version: 1.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1645542019; l=1645; s=20211009; h=from:subject:message-id; bh=K04OWtjguCoft4Etc2/16pdJhJKZWZgWbhOpnNSgE7U=; b=02AslvbJ+42xnFSeBtNyfdLYNjaGt1O0uw43lPDM76mPLYfkdPVuiu0PB1rdptWrEoJFQtyvN4M/ ERHYtoZZCvyWYxoHT8Xy1AJVPsdTo+xC0ybeTgDmzF9rpXMotnu6 X-Developer-Key: i=christophe.leroy@csgroup.eu; a=ed25519; pk=HIzTzUj91asvincQGOFx6+ZF5AoUuP9GdOtQChs7Mm0= Precedence: bulk List-ID: book3s/32 and 8xx have a separate area for allocating modules, defined by MODULES_VADDR / MODULES_END. On book3s/32, it is not possible to protect against execution on a page basis. A full 256M segment is either Exec or NoExec. The module area is in an Exec segment while vmalloc area is in a NoExec segment. In order to protect module data against execution, select ARCH_WANTS_MODULES_DATA_IN_VMALLOC. For the 8xx (and possibly other 32 bits platform in the future), there is no such constraint on Exec/NoExec protection, however there is a critical distance between kernel functions and callers that needs to remain below 32Mbytes in order to avoid costly trampolines. By allocating data outside of module area, we increase the chance for module text to remain within acceptable distance from kernel core text. So select ARCH_WANTS_MODULES_DATA_IN_VMALLOC for 8xx as well. Signed-off-by: Christophe Leroy Cc: Michael Ellerman Cc: Benjamin Herrenschmidt Cc: Paul Mackerras --- arch/powerpc/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 28e4047e99e8..478ee49a4fb4 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -156,6 +156,7 @@ config PPC select ARCH_WANT_IPC_PARSE_VERSION select ARCH_WANT_IRQS_OFF_ACTIVATE_MM select ARCH_WANT_LD_ORPHAN_WARN + select ARCH_WANTS_MODULES_DATA_IN_VMALLOC if PPC_BOOK3S_32 || PPC_8xx select ARCH_WEAK_RELEASE_ACQUIRE select BINFMT_ELF select BUILDTIME_TABLE_SORT