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 E35FEC433EF for ; Tue, 7 Jun 2022 21:27:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1378338AbiFGV1T (ORCPT ); Tue, 7 Jun 2022 17:27:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44714 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1377616AbiFGUdx (ORCPT ); Tue, 7 Jun 2022 16:33:53 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6E1761E562E; Tue, 7 Jun 2022 11:35:33 -0700 (PDT) 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 A0FBEB8237C; Tue, 7 Jun 2022 18:35:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id ED334C385A2; Tue, 7 Jun 2022 18:35:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1654626931; bh=K1VJeX5GCDsY+9X8S0bObVsEpIXlCrJ6Ne/vbZkkzvU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FR+jnPisAy8yUUHtryOpQrOo6wNnzXmeQlQMs9bvH/V1+xo4GAbEWjk1cVLZYck4+ QTi6TJsqkP7IWNZ5yLkMzBmeR8/4Opn94CJWbMugZHElPDyS/5zrGmi3qfFLg8L+pa KoXTEv6m0/+QihovVwi49YYMeA5Mk/e+lBlxJkdA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Guenter Roeck , Christophe Leroy , Michael Ellerman , Sasha Levin Subject: [PATCH 5.17 554/772] powerpc/fsl_book3e: Dont set rodata RO too early Date: Tue, 7 Jun 2022 19:02:26 +0200 Message-Id: <20220607165005.286053255@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220607164948.980838585@linuxfoundation.org> References: <20220607164948.980838585@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Christophe Leroy [ Upstream commit ad91f66f5fa7c6f9346e721c3159ce818568028b ] On fsl_book3e, rodata is set read-only at the same time as init text is set NX at the end of init. That's too early. As both action are performed at the same time, delay both actions to the time rodata is expected to be made read-only. It means we will have a small window with init mem freed but still executable. It shouldn't be an issue though, especially because the said memory gets poisoned and should therefore result to a bad instruction fault in case it gets executed. mmu_mark_initmem_nx() is bailing out before doing anything when CONFIG_STRICT_KERNEL_RWX is not selected or rodata_enabled is false. mmu_mark_rodata_ro() is called only when CONFIG_STRICT_KERNEL_RWX is selected and rodata_enabled is true so this is equivalent. Move code from mmu_mark_initmem_nx() into mmu_mark_rodata_ro() and remove the call to strict_kernel_rwx_enabled() which is not needed anymore. Fixes: d5970045cf9e ("powerpc/fsl_booke: Update of TLBCAMs after init") Reported-by: Guenter Roeck Tested-by: Guenter Roeck Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/2e35f0fd649c83c5add17a99514ac040767be93a.1652981047.git.christophe.leroy@csgroup.eu Signed-off-by: Sasha Levin --- arch/powerpc/mm/nohash/fsl_book3e.c | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) diff --git a/arch/powerpc/mm/nohash/fsl_book3e.c b/arch/powerpc/mm/nohash/fsl_book3e.c index dfe715e0f70a..388f7c7dabd3 100644 --- a/arch/powerpc/mm/nohash/fsl_book3e.c +++ b/arch/powerpc/mm/nohash/fsl_book3e.c @@ -287,22 +287,19 @@ void __init adjust_total_lowmem(void) #ifdef CONFIG_STRICT_KERNEL_RWX void mmu_mark_rodata_ro(void) -{ - /* Everything is done in mmu_mark_initmem_nx() */ -} -#endif - -void mmu_mark_initmem_nx(void) { unsigned long remapped; - if (!strict_kernel_rwx_enabled()) - return; - remapped = map_mem_in_cams(__max_low_memory, CONFIG_LOWMEM_CAM_NUM, false, false); WARN_ON(__max_low_memory != remapped); } +#endif + +void mmu_mark_initmem_nx(void) +{ + /* Everything is done in mmu_mark_rodata_ro() */ +} void setup_initial_memory_limit(phys_addr_t first_memblock_base, phys_addr_t first_memblock_size) -- 2.35.1