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=unavailable 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 427F9C433DF for ; Tue, 9 Jun 2020 00:14:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 11A4320890 for ; Tue, 9 Jun 2020 00:14:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591661648; bh=q2rVo/aR3JTRBRIML0kZmbB8f0+fBsJ6fAx8XSXDfSQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=CwXI8lcVRp2m2jqhw4sQ8waLDABRNOXZS2TNFoNPYZBdNi6FJNlRqfqDg2dZoE1zk DcwWpKMSrCcRI3d3B1LbmBM2reyB1RzpmeG8R3OsjkTJdBvHkEIX1KJfgMEqRT5esC 5pVrmEa3VsrB+pxe0aKgSYGmUhe7M4lKFvytFKJw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731074AbgFIAOF (ORCPT ); Mon, 8 Jun 2020 20:14:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:42068 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730421AbgFHXTS (ORCPT ); Mon, 8 Jun 2020 19:19:18 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (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 B52C920842; Mon, 8 Jun 2020 23:19:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591658358; bh=q2rVo/aR3JTRBRIML0kZmbB8f0+fBsJ6fAx8XSXDfSQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aa5n72AiMtnCQmsm8//nZX5NDE1rEY+xWIPfflU4XI+iKjlUoVk+HHL11solShQHx c8f9VoLyljD5+7gKiVbc0w1y2l6kfXqshbUe8I8lO5NpBrUO+Bp3FiR22wcmnHI6c9 SSHR6wOtvy1W23NVE4iTnxoEZlI1shB50Wc4YYGY= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Daniel Thompson , Douglas Anderson , Will Deacon , Sasha Levin , linux-arm-kernel@lists.infradead.org Subject: [PATCH AUTOSEL 5.4 024/175] arm64: cacheflush: Fix KGDB trap detection Date: Mon, 8 Jun 2020 19:16:17 -0400 Message-Id: <20200608231848.3366970-24-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200608231848.3366970-1-sashal@kernel.org> References: <20200608231848.3366970-1-sashal@kernel.org> MIME-Version: 1.0 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: Daniel Thompson [ Upstream commit ab8ad279ceac4fc78ae4dcf1a26326e05695e537 ] flush_icache_range() contains a bodge to avoid issuing IPIs when the kgdb trap handler is running because issuing IPIs is unsafe (and not needed) in this execution context. However the current test, based on kgdb_connected is flawed: it both over-matches and under-matches. The over match occurs because kgdb_connected is set when gdb attaches to the stub and remains set during normal running. This is relatively harmelss because in almost all cases irq_disabled() will be false. The under match is more serious. When kdb is used instead of kgdb to access the debugger then kgdb_connected is not set in all the places that the debug core updates sw breakpoints (and hence flushes the icache). This can lead to deadlock. Fix by replacing the ad-hoc check with the proper kgdb macro. This also allows us to drop the #ifdef wrapper. Fixes: 3b8c9f1cdfc5 ("arm64: IPI each CPU after invalidating the I-cache for kernel mappings") Signed-off-by: Daniel Thompson Reviewed-by: Douglas Anderson Link: https://lore.kernel.org/r/20200504170518.2959478-1-daniel.thompson@linaro.org Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- arch/arm64/include/asm/cacheflush.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h index 665c78e0665a..3e7dda6f1ab1 100644 --- a/arch/arm64/include/asm/cacheflush.h +++ b/arch/arm64/include/asm/cacheflush.h @@ -79,7 +79,7 @@ static inline void flush_icache_range(unsigned long start, unsigned long end) * IPI all online CPUs so that they undergo a context synchronization * event and are forced to refetch the new instructions. */ -#ifdef CONFIG_KGDB + /* * KGDB performs cache maintenance with interrupts disabled, so we * will deadlock trying to IPI the secondary CPUs. In theory, we can @@ -89,9 +89,9 @@ static inline void flush_icache_range(unsigned long start, unsigned long end) * the patching operation, so we don't need extra IPIs here anyway. * In which case, add a KGDB-specific bodge and return early. */ - if (kgdb_connected && irqs_disabled()) + if (in_dbg_master()) return; -#endif + kick_all_cpus_sync(); } -- 2.25.1