From patchwork Tue Feb 22 10:32:20 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 12754806 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 A3C8CC433F5 for ; Tue, 22 Feb 2022 10:32:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231153AbiBVKdS (ORCPT ); Tue, 22 Feb 2022 05:33:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59122 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229785AbiBVKdQ (ORCPT ); Tue, 22 Feb 2022 05:33:16 -0500 Received: from pegase2.c-s.fr (pegase2.c-s.fr [93.17.235.10]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 08D59159E9C; Tue, 22 Feb 2022 02:32:51 -0800 (PST) Received: from localhost (mailhub3.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4K2wV94QtFz9sSj; Tue, 22 Feb 2022 11:32:49 +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 KhXs1n8nazcn; Tue, 22 Feb 2022 11:32:49 +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 4K2wV93ZFcz9sS4; Tue, 22 Feb 2022 11:32:49 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 678BE8B781; Tue, 22 Feb 2022 11:32:49 +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 aAHTjz21EQky; Tue, 22 Feb 2022 11:32:49 +0100 (CET) Received: from PO20335.IDSI0.si.c-s.fr (unknown [172.25.230.108]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 290468B77B; Tue, 22 Feb 2022 11:32:49 +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 21MAWiFp1075982 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Tue, 22 Feb 2022 11:32:44 +0100 Received: (from chleroy@localhost) by PO20335.IDSI0.si.c-s.fr (8.17.1/8.17.1/Submit) id 21MAWhg21075981; Tue, 22 Feb 2022 11:32:43 +0100 X-Authentication-Warning: PO20335.IDSI0.si.c-s.fr: chleroy set sender to christophe.leroy@csgroup.eu using -f From: Christophe Leroy To: Aaron Tomlin , Luis Chamberlain , Jessica Yu 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 v4 6/6] powerpc: Select ARCH_WANTS_MODULES_DATA_IN_VMALLOC on book3s/32 and 8xx Date: Tue, 22 Feb 2022 11:32:20 +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=1645525928; l=1645; s=20211009; h=from:subject:message-id; bh=K04OWtjguCoft4Etc2/16pdJhJKZWZgWbhOpnNSgE7U=; b=hpk03SBCszNo742+2VK/eQLT92kOJCrSS+maM/ldh4eoCtbxQ0D87Y7BYTqu+2LyHwxlc99CUMOc cc433DAAB/dzMLBXJGZIifit9O7AQfafd+1sMzIYAzRMqytJi3zJ 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