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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 959DDC433F5 for ; Wed, 13 Oct 2021 00:57:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 777C360232 for ; Wed, 13 Oct 2021 00:57:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236177AbhJMA7I (ORCPT ); Tue, 12 Oct 2021 20:59:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:41106 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236683AbhJMA5v (ORCPT ); Tue, 12 Oct 2021 20:57:51 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7610460F21; Wed, 13 Oct 2021 00:55:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1634086548; bh=tZDxhnml6J/pYC6SCT4v70fUfCAV5raH4h8fIzLk93Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qyLm83J6ywJQwKpG0kOI2fi3xx6ljHUIaij1SOViI/R/XP31vW5lHJorApPE5xY3X 2VqtcqiKDQJcFbFwtijTSKsWtt39AXP4Z0vbks1by80xxzFCqjc9LJOZQwMQq/EyLH v/vrkZj6H455d2W1cSPdslVh/U5IWn2t28wk8wkAJp29dgyf1ccGOUzo0If/Rv9JgM aOqedwZrLO3QsseopaZY+XNiEwAq4RLVx1A5aDB3xzV1UHZED7vd1JQsxBnImu5BBk AVS6+f6axyi3bIzwdxVJdGZxNB0jxqCdBMN/9PXdTd22AlBLu7K6Jl0a/pjVaqVRxB mx5IsOIS7iMpQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Guenter Roeck , Max Filippov , Sasha Levin , chris@zankel.net, linux-xtensa@linux-xtensa.org Subject: [PATCH AUTOSEL 5.10 08/11] xtensa: xtfpga: Try software restart before simulating CPU reset Date: Tue, 12 Oct 2021 20:55:28 -0400 Message-Id: <20211013005532.700190-8-sashal@kernel.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211013005532.700190-1-sashal@kernel.org> References: <20211013005532.700190-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Guenter Roeck [ Upstream commit 012e974501a270d8dfd4ee2039e1fdf7579c907e ] Rebooting xtensa images loaded with the '-kernel' option in qemu does not work. When executing a reboot command, the qemu session either hangs or experiences an endless sequence of error messages. Kernel panic - not syncing: Unrecoverable error in exception handler Reset code jumps to the CPU restart address, but Linux can not recover from there because code and data in the kernel init sections have been discarded and overwritten at this point. XTFPGA platforms have a means to reset the CPU by writing 0xdead into a specific FPGA IO address. When used in QEMU the kernel image loaded with the '-kernel' option gets restored to its original state allowing the machine to boot successfully. Use that mechanism to attempt a platform reset. If it does not work, fall back to the existing mechanism. Signed-off-by: Guenter Roeck Signed-off-by: Max Filippov Signed-off-by: Sasha Levin --- arch/xtensa/platforms/xtfpga/setup.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/xtensa/platforms/xtfpga/setup.c b/arch/xtensa/platforms/xtfpga/setup.c index 59b7f11f2a3e..538e6748e85a 100644 --- a/arch/xtensa/platforms/xtfpga/setup.c +++ b/arch/xtensa/platforms/xtfpga/setup.c @@ -51,8 +51,12 @@ void platform_power_off(void) void platform_restart(void) { - /* Flush and reset the mmu, simulate a processor reset, and - * jump to the reset vector. */ + /* Try software reset first. */ + WRITE_ONCE(*(u32 *)XTFPGA_SWRST_VADDR, 0xdead); + + /* If software reset did not work, flush and reset the mmu, + * simulate a processor reset, and jump to the reset vector. + */ cpu_reset(); /* control never gets here */ } -- 2.33.0