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 X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 19AFFC3A5A1 for ; Thu, 22 Aug 2019 17:19:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E198D233FC for ; Thu, 22 Aug 2019 17:19:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566494385; bh=RuOsYf5TN5Hw5cPbpR48OEF6lAqy3ny4adgENjVkcnM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=z1Eh9oar35suwpN8/vyG/7VN5LFaFGdrNy8p1F21bKcsewXgOsnkZ7fpGzajrOqDr ni2BaY3gtWrHwdXDtq6Q+4zU8Ds+kYXGYeVaWPUVXATDj2mTbwg0ZjQAok86i4nhix pLS9tD9C+m5XKBMGROrNFBCeihm6PPhGt4JvQyjI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388325AbfHVRTo (ORCPT ); Thu, 22 Aug 2019 13:19:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:57978 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390298AbfHVRIY (ORCPT ); Thu, 22 Aug 2019 13:08:24 -0400 Received: from sasha-vm.mshome.net (wsip-184-188-36-2.sd.sd.cox.net [184.188.36.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5A65823407; Thu, 22 Aug 2019 17:08:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566493703; bh=RuOsYf5TN5Hw5cPbpR48OEF6lAqy3ny4adgENjVkcnM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1hW+KQy4i5J/W/IpXHN4VBtriUHVCdnEc97faN+aGMJK2tsFtZt8qYZnM8cQJddPg zNt7i45Go6ZmqlHIxgSR7mTxZyHtpzCHg7nE4w+P9jWPBtA+U3D+fXYJck530yOBLT n9RuAUYoUsqc0loY0AikrnKkkbTdSBP9yjcvilOw= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Will Deacon , Ard Biesheuvel , James Morse , Catalin Marinas , Greg Kroah-Hartman Subject: [PATCH 5.2 016/135] arm64: ftrace: Ensure module ftrace trampoline is coherent with I-side Date: Thu, 22 Aug 2019 13:06:12 -0400 Message-Id: <20190822170811.13303-17-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190822170811.13303-1-sashal@kernel.org> References: <20190822170811.13303-1-sashal@kernel.org> MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.2.10-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-5.2.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 5.2.10-rc1 X-KernelTest-Deadline: 2019-08-24T17:07+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Will Deacon commit b6143d10d23ebb4a77af311e8b8b7f019d0163e6 upstream. The initial support for dynamic ftrace trampolines in modules made use of an indirect branch which loaded its target from the beginning of a special section (e71a4e1bebaf7 ("arm64: ftrace: add support for far branches to dynamic ftrace")). Since no instructions were being patched, no cache maintenance was needed. However, later in be0f272bfc83 ("arm64: ftrace: emit ftrace-mod.o contents through code") this code was reworked to output the trampoline instructions directly into the PLT entry but, unfortunately, the necessary cache maintenance was overlooked. Add a call to __flush_icache_range() after writing the new trampoline instructions but before patching in the branch to the trampoline. Cc: Ard Biesheuvel Cc: James Morse Cc: Fixes: be0f272bfc83 ("arm64: ftrace: emit ftrace-mod.o contents through code") Signed-off-by: Will Deacon Signed-off-by: Catalin Marinas Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/ftrace.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-) diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c index 1285c7b2947fa..1717732579742 100644 --- a/arch/arm64/kernel/ftrace.c +++ b/arch/arm64/kernel/ftrace.c @@ -73,7 +73,7 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) if (offset < -SZ_128M || offset >= SZ_128M) { #ifdef CONFIG_ARM64_MODULE_PLTS - struct plt_entry trampoline; + struct plt_entry trampoline, *dst; struct module *mod; /* @@ -106,23 +106,27 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) * to check if the actual opcodes are in fact identical, * regardless of the offset in memory so use memcmp() instead. */ - trampoline = get_plt_entry(addr, mod->arch.ftrace_trampoline); - if (memcmp(mod->arch.ftrace_trampoline, &trampoline, - sizeof(trampoline))) { - if (plt_entry_is_initialized(mod->arch.ftrace_trampoline)) { + dst = mod->arch.ftrace_trampoline; + trampoline = get_plt_entry(addr, dst); + if (memcmp(dst, &trampoline, sizeof(trampoline))) { + if (plt_entry_is_initialized(dst)) { pr_err("ftrace: far branches to multiple entry points unsupported inside a single module\n"); return -EINVAL; } /* point the trampoline to our ftrace entry point */ module_disable_ro(mod); - *mod->arch.ftrace_trampoline = trampoline; + *dst = trampoline; module_enable_ro(mod, true); - /* update trampoline before patching in the branch */ - smp_wmb(); + /* + * Ensure updated trampoline is visible to instruction + * fetch before we patch in the branch. + */ + __flush_icache_range((unsigned long)&dst[0], + (unsigned long)&dst[1]); } - addr = (unsigned long)(void *)mod->arch.ftrace_trampoline; + addr = (unsigned long)dst; #else /* CONFIG_ARM64_MODULE_PLTS */ return -EINVAL; #endif /* CONFIG_ARM64_MODULE_PLTS */ -- 2.20.1