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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 C4D09CD1288 for ; Wed, 3 Apr 2024 17:52:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=G6Qb+IxiFG1sKhiWB4ECPljp7IrykhdJBddSDJSNTF0=; b=uSUXnsBvOeIpv/ QMbfS1tlQwbg5xexxTI2jW58xPuQgBlZgmMroZu62685ZSkBw424zouOPiZwak9rSakj803wapLVL p4oApq1mEN4zk3TAlblQKuUo6iQ6PHgm8rbGyCQ1s9Vs3UwxrqeIgE+nqcRY0ClUESHgZlAhYLP/f tsbye5/5xdZhxN/S3iXUZ+hSz4zKr2PosLFKDp6b6xrwe95LKZn5fPIxikClBJVb3kceCYpGuH2xF RVTW+52SGlMWA05rK0FpJiZSrPq8pGspwpFfe34679LFdX0WBkRpCBfsDZQGzXZzx2pKX6srNN/HW FHn67v0EKQHKdfNOZi1A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rs4mu-0000000HGqV-0MT4; Wed, 03 Apr 2024 17:52:40 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rs4mq-0000000HGp4-0TzU for linux-arm-kernel@lists.infradead.org; Wed, 03 Apr 2024 17:52:37 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 5BD2F60B6D; Wed, 3 Apr 2024 17:52:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A32A9C433C7; Wed, 3 Apr 2024 17:52:32 +0000 (UTC) Date: Wed, 3 Apr 2024 18:52:30 +0100 From: Catalin Marinas To: Mark Rutland Cc: linux-kernel@vger.kernel.org, Will Deacon , anil.s.keshavamurthy@intel.com, aou@eecs.berkeley.edu, davem@davemloft.net, jarkko@kernel.org, linux-arm-kernel@lists.infradead.org, mhiramat@kernel.org, naveen.n.rao@linux.ibm.com, palmer@dabbelt.com, paul.walmsley@sifive.com Subject: Re: [PATCH v2 1/4] arm64: patching: always use fixmap Message-ID: References: <20240403150154.667649-1-mark.rutland@arm.com> <20240403150154.667649-2-mark.rutland@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20240403150154.667649-2-mark.rutland@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240403_105236_404352_0A0FA5F5 X-CRM114-Status: GOOD ( 20.87 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Apr 03, 2024 at 04:01:51PM +0100, Mark Rutland wrote: > For historical reasons, patch_map() won't bother to fixmap non-image > addresses when CONFIG_STRICT_MODULE_RWX=n, matching the behaviour prior > to the introduction of CONFIG_STRICT_MODULE_RWX. However, as arm64 > doesn't select CONFIG_ARCH_OPTIONAL_KERNEL_RWX, CONFIG_MODULES implies > CONFIG_STRICT_MODULE_RWX, so any kernel built with module support will > use the fixmap for any non-image address. > > Historically we only used patch_map() for the kernel image and modules, > but these days its also used by BPF and KPROBES to write to read-only > pages of executable text. Currently these both depend on CONFIG_MODULES, > but we'd like to change that in subsequent patches, which will require > using the fixmap regardless of CONFIG_STRICT_MODULE_RWX. > > This patch changes patch_map() to always use the fixmap, and simplifies > the logic: > > * Use is_image_text() directly in the if-else, rather than using a > temporary boolean variable. > > * Use offset_in_page() to get the offset within the mapping. > > * Remove uintaddr and cast the address directly when using > is_image_text(). > > For kernels built with CONFIG_MODULES=y, there should be no functional > change as a result of this patch. > > For kernels built with CONFIG_MODULES=n, patch_map() will use the fixmap > for non-image addresses, but there are no extant users with non-image > addresses when CONFIG_MODULES=n, and hence there should be no functional > change as a result of this patch alone. > > Signed-off-by: Mark Rutland > Cc: Catalin Marinas > Cc: Will Deacon > --- > arch/arm64/kernel/patching.c | 10 +++------- > 1 file changed, 3 insertions(+), 7 deletions(-) > > Catalin, Will, this is a prerequisite for the final two patches in the > series. Are you happy for this go via the tracing tree? Fine by me. Acked-by: Catalin Marinas _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel