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 02D75CD1292 for ; Wed, 3 Apr 2024 15:02:26 +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:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=gHxuF1aIQ68tQ3inoEZoyyygkPOv3PFRFbmrN+7LzbM=; b=24wUaEpn5rx3JA sAOEDMYrS5AIaNZMz1Mi3JCPZTATO4MY2BSzPobrhO3YMgrszPtI1iCTVAz9vuTOPYC1JEwAzXfBF avHnl1sHpTEEw3S+1Sv+oGGG926VaeZxdtmX1qzR3oNZnjSgAJv9jPbzLpbipu17/EX/yRmY/2/Ix a6gC+5EBJvdMFVBncEspXnbsMYTum5uPvTSNTSd1dmvrU1CceY5MC8Dt+o9Y15zY6qFugWYMalAsb Dgodmxez79/aj5SlRU80lcykiEMtOzWyZZkhM0FgJtxKAOZhpf7C9zTdMWlrVlJT2Pc4Y5I/PHxrV PMH7i1+nWXlUZ2n/rmPQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rs27u-0000000GbCR-4Bbc; Wed, 03 Apr 2024 15:02:11 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rs27p-0000000Gb9H-05Ij for linux-arm-kernel@lists.infradead.org; Wed, 03 Apr 2024 15:02:08 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 725511595; Wed, 3 Apr 2024 08:02:35 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id C2F883F7B4; Wed, 3 Apr 2024 08:02:02 -0700 (PDT) From: Mark Rutland To: linux-kernel@vger.kernel.org, Catalin Marinas , Will Deacon Cc: anil.s.keshavamurthy@intel.com, aou@eecs.berkeley.edu, davem@davemloft.net, jarkko@kernel.org, linux-arm-kernel@lists.infradead.org, mark.rutland@arm.com, mhiramat@kernel.org, naveen.n.rao@linux.ibm.com, palmer@dabbelt.com, paul.walmsley@sifive.com Subject: [PATCH v2 1/4] arm64: patching: always use fixmap Date: Wed, 3 Apr 2024 16:01:51 +0100 Message-Id: <20240403150154.667649-2-mark.rutland@arm.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20240403150154.667649-1-mark.rutland@arm.com> References: <20240403150154.667649-1-mark.rutland@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240403_080205_458552_BA8F8AAF X-CRM114-Status: GOOD ( 13.59 ) 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 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? Mark. diff --git a/arch/arm64/kernel/patching.c b/arch/arm64/kernel/patching.c index 2555349303684..f0f3a2a82ca5a 100644 --- a/arch/arm64/kernel/patching.c +++ b/arch/arm64/kernel/patching.c @@ -30,20 +30,16 @@ static bool is_image_text(unsigned long addr) static void __kprobes *patch_map(void *addr, int fixmap) { - unsigned long uintaddr = (uintptr_t) addr; - bool image = is_image_text(uintaddr); struct page *page; - if (image) + if (is_image_text((unsigned long)addr)) page = phys_to_page(__pa_symbol(addr)); - else if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX)) - page = vmalloc_to_page(addr); else - return addr; + page = vmalloc_to_page(addr); BUG_ON(!page); return (void *)set_fixmap_offset(fixmap, page_to_phys(page) + - (uintaddr & ~PAGE_MASK)); + offset_in_page(addr)); } static void __kprobes patch_unmap(int fixmap) -- 2.30.2 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel