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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8DDD1CA9ED0 for ; Mon, 12 Oct 2026 10:28:48 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4j3DG66RNRz2xwP; Mon, 12 Oct 2026 21:28:46 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip="2600:3c04:e001:324:0:1991:8:25" ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1791800926; cv=none; b=KmS4DPwJuGaIdsy4eZejy9YzEQvfJCO8t/9viyN1tBq5Kh7nGVyQI6nVJSkp961GRuorKHtTe29IvYw51bZ20PMzq+4G+3a4/sMSqAByvJGEeo/ivVe6csFUXDp+2lgtRBZ25sIjEguTnNh1MGd93mnOuQyLDWE1Vqa36PktPhC1hdzA2MEfD5GsauoRjKD13+ZeMMdXVVbo8yZ6N5Y5kAhU0F/sL0s59F96wxJ7NWtBMgvZWMcBGvLnwYp3FD78tZi+Tj9P6mf96aml24E/WHcp9jEtGN5P5YaeIa/Yvm0L41bCyoF9ljytRLKVSvAVqBsXRBtb/IK1QfTIz1AhAQ== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1791800926; c=relaxed/relaxed; bh=9SqsLlEeY8Z7JWwzaLCKZ/Afkt3yxtAt34Q/0TSpfLw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=QLZoOpQ9Z8OfVMWlujsp1bLPR0R7O0wZJOM7sIgJdSS219wm3O9U4hERbT60UsEGMwAZO5+Qkh6ULLNVQGeFAeuSypQWb2elJE950+FLvP5iLdxiNXZD3rna2Bb0ugvCjDFMJPY0F7qPUtLQ4Pxmc2KX6swd/Kcu10ITbLE3UNj+yBGgkiYB7xQfa3D+pj7EjEucv7DeUXEsmmsADpC4AtTOWlNfkCm/7bdidD+m4p6XXUwkXEYrGPcX3POegVGAqbEOFIdPZ0wf6porV1vF0ffg0obH5qMI1WFhcQoo3lXCYXkC1VjBhJ2dzApF75hMaD5zZZ1FOD0eC7n6gKVs4A== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=kernel.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=K1/3XoFu; dkim-atps=neutral; spf=pass (client-ip=2600:3c04:e001:324:0:1991:8:25; helo=tor.source.kernel.org; envelope-from=chleroy@kernel.org; receiver=lists.ozlabs.org) smtp.mailfrom=kernel.org Authentication-Results: lists.ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=kernel.org Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=K1/3XoFu; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=2600:3c04:e001:324:0:1991:8:25; helo=tor.source.kernel.org; envelope-from=chleroy@kernel.org; receiver=lists.ozlabs.org) Received: from tor.source.kernel.org (tor.source.kernel.org [IPv6:2600:3c04:e001:324:0:1991:8:25]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4j3DG5715jz2xwM for ; Mon, 12 Oct 2026 21:28:45 +1100 (AEDT) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id B6EF1601FE; Mon, 12 Oct 2026 10:28:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4A54D1F0089B; Mon, 12 Oct 2026 10:28:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791800922; bh=9SqsLlEeY8Z7JWwzaLCKZ/Afkt3yxtAt34Q/0TSpfLw=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=K1/3XoFuG4eFCz4OgQUA5uvMw5WFNnU7QPlivAAaTatqVPi3cfWD+k64Z4caemYUQ 6iP+1uGhOTfGoAspZ0yAGGysurE2NeOJ5wN6/EHkGksFKdoIM+uwlBCHyYUb4vQl6Z OhASdimiqXso6Xgzsh0CMCMLrSLqqjdSjcJnYJYdeDH1Yelk49tF+ucS16RTNOvZTZ 7fpBuvNP3YxfABcb0X+tOBjhQ9+eaKVdyHibNaedLJi5idk6wxyUPKS8nCf1fLcoF0 uBY1H99GdHtmZaqphKNxl+QzSIWXXDfgm3VT2qELvVg9XmWjkeVJJtRzqTyryR1qV4 P/gDk2LoIF8mQ== Message-ID: Date: Mon, 12 Oct 2026 12:28:37 +0200 X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] powerpc/Kconfig: limit the PPC_85xx DATA_SHIFT range to STRICT_KERNEL_RWX To: Julian Braha , maddy@linux.ibm.com Cc: mpe@ellerman.id.au, npiggin@gmail.com, ritesh.list@gmail.com, sshegde@linux.ibm.com, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org References: <20261011113108.539470-1-julianbraha@gmail.com> Content-Language: fr-FR From: "Christophe Leroy (CS GROUP)" In-Reply-To: <20261011113108.539470-1-julianbraha@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Le 11/10/2026 à 13:31, Julian Braha a écrit : > On PPC_85xx, enabling DEBUG_PAGEALLOC without STRICT_KERNEL_RWX activates > the DATA_SHIFT range of 20..24, but since the PAGE_SHIFT default is > outside the range (12), kconfig adjusts it to 20, causing 1mb alignment > instead of 4kb. However, the larger alignment is only needed for the > separate kernel permissions provided by STRICT_KERNEL_RWX. > > Since PPC_85xx uses page poisoning for DEBUG_PAGEALLOC and does not > support KFENCE, let's restrict this range to STRICT_KERNEL_RWX. > > This out-of-range default was detected by kconfirm, a static analysis tool > for Kconfig. Looks like with this change I'm now able to set DATA_SHIFT to any value when STRICT_KERNEL_RWX is not set and DEBUG_PAGEALLOC is set. The range used to protect against that. > > Signed-off-by: Julian Braha > --- > arch/powerpc/Kconfig | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig > index c3b6cd655606..5e2a4799438d 100644 > --- a/arch/powerpc/Kconfig > +++ b/arch/powerpc/Kconfig > @@ -896,7 +896,7 @@ config DATA_SHIFT > default 24 if STRICT_KERNEL_RWX && PPC64 > range 17 28 if (STRICT_KERNEL_RWX || DEBUG_PAGEALLOC || KFENCE) && PPC_BOOK3S_32 > range 14 23 if (STRICT_KERNEL_RWX || DEBUG_PAGEALLOC || KFENCE) && PPC_8xx > - range 20 24 if (STRICT_KERNEL_RWX || DEBUG_PAGEALLOC || KFENCE) && PPC_85xx > + range 20 24 if STRICT_KERNEL_RWX && PPC_85xx > default 22 if STRICT_KERNEL_RWX && PPC_BOOK3S_32 > default 18 if (DEBUG_PAGEALLOC || KFENCE) && PPC_BOOK3S_32 > default 23 if (STRICT_KERNEL_RWX || DEBUG_PAGEALLOC || KFENCE) && PPC_8xx && \