From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C89F6156C4B for ; Wed, 3 Apr 2024 23:44:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712187896; cv=none; b=R7EGpEd+ZSGT568UVIeZHx61BSF3NAmYSo/XlJ5dGGIPLXUpc5A5h5PEk0j1CHzhXhgG/57j+AmXCUZXxoogy9rLf8DBIAXejFKNoQGKid/lwJ053h384VJHllFO7dlQbdIOZDaNBwqh6grzW4eq+kK7tSyJBD36B2SPaSpEzHA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712187896; c=relaxed/simple; bh=km9WrjrljLnrGGBMhJMqtSVQkEOEoORatY4UgWPCrhI=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=pvaYXdtTRhggA4dBSLBEUt9khCL0Yu3BZebIc7VNiRCEd+uSRDGduB6USQ9ksEHR5/TGtQV9Az9dtQqkLi3qEWlCdes3AOM1myb3RJpQA5tbPCi9GqeF22zm3rUFZiJukTqcXJ6+nvAiI0U9eyqB6Uk/KcZ8W33eXVKeQjl0jIk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RV7GYcjm; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RV7GYcjm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 27297C43390; Wed, 3 Apr 2024 23:44:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1712187896; bh=km9WrjrljLnrGGBMhJMqtSVQkEOEoORatY4UgWPCrhI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=RV7GYcjmC1peJ0K+6FY0qq/5hSfZCqUJ2QNUdpb36t3OAFaxi4FIhiRPOlfjWOmB+ /ud3+bqKCOc8B7qynP/pFR9M6i2xUeFZC2o5G/FIWr86jnalK6ebcSYxmezEfEAAwY qEzEr4Q/6wcwSKE6hfjU4gyCyoZQsyrTUL37YxInBx03Rvu/aGC3Dg7ddui9zju7zT u5HYDBHA4woR7MjA0UIH5lJ5bros70GI7v/Mv0q9sIrhKtnwgdp13v6VgBCR22I3rW SSV9EGak+zZhFFO3HON2I/X992RARtXhQdSsERIO7HiMey7dt6+AEbK8dqX8KTWxCm RitZLYXh9l5lQ== Date: Thu, 4 Apr 2024 08:44:50 +0900 From: Masami Hiramatsu (Google) To: Catalin Marinas Cc: Mark Rutland , 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: <20240404084450.802bae64e3ed08197fd0dad1@kernel.org> In-Reply-To: References: <20240403150154.667649-1-mark.rutland@arm.com> <20240403150154.667649-2-mark.rutland@arm.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Wed, 3 Apr 2024 18:52:30 +0100 Catalin Marinas wrote: > 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 Thanks Catalin. I'll pick this series to linux-trace tree. Thank you! -- Masami Hiramatsu (Google)