From patchwork Fri Oct 8 09:25:46 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mathias Nyman X-Patchwork-Id: 12544713 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 42152C433EF for ; Fri, 8 Oct 2021 09:23:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 24FDB61019 for ; Fri, 8 Oct 2021 09:23:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237621AbhJHJZS (ORCPT ); Fri, 8 Oct 2021 05:25:18 -0400 Received: from mga01.intel.com ([192.55.52.88]:41430 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235969AbhJHJZQ (ORCPT ); Fri, 8 Oct 2021 05:25:16 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10130"; a="249830696" X-IronPort-AV: E=Sophos;i="5.85,357,1624345200"; d="scan'208";a="249830696" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Oct 2021 02:23:21 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.85,357,1624345200"; d="scan'208";a="489390552" Received: from mattu-haswell.fi.intel.com ([10.237.72.170]) by orsmga008.jf.intel.com with ESMTP; 08 Oct 2021 02:23:19 -0700 From: Mathias Nyman To: Cc: , Pavankumar Kondeti , stable@vger.kernel.org, Mathias Nyman Subject: [PATCH 4/5] xhci: Fix command ring pointer corruption while aborting a command Date: Fri, 8 Oct 2021 12:25:46 +0300 Message-Id: <20211008092547.3996295-5-mathias.nyman@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211008092547.3996295-1-mathias.nyman@linux.intel.com> References: <20211008092547.3996295-1-mathias.nyman@linux.intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Pavankumar Kondeti The command ring pointer is located at [6:63] bits of the command ring control register (CRCR). All the control bits like command stop, abort are located at [0:3] bits. While aborting a command, we read the CRCR and set the abort bit and write to the CRCR. The read will always give command ring pointer as all zeros. So we essentially write only the control bits. Since we split the 64 bit write into two 32 bit writes, there is a possibility of xHC command ring stopped before the upper dword (all zeros) is written. If that happens, xHC updates the upper dword of its internal command ring pointer with all zeros. Next time, when the command ring is restarted, we see xHC memory access failures. Fix this issue by only writing to the lower dword of CRCR where all control bits are located. Signed-off-by: Pavankumar Kondeti Cc: stable@vger.kernel.org Signed-off-by: Mathias Nyman --- drivers/usb/host/xhci-ring.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 7dbd26a9bc24..311597bba80e 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -366,16 +366,22 @@ static void xhci_handle_stopped_cmd_ring(struct xhci_hcd *xhci, /* Must be called with xhci->lock held, releases and aquires lock back */ static int xhci_abort_cmd_ring(struct xhci_hcd *xhci, unsigned long flags) { - u64 temp_64; + u32 temp_32; int ret; xhci_dbg(xhci, "Abort command ring\n"); reinit_completion(&xhci->cmd_ring_stop_completion); - temp_64 = xhci_read_64(xhci, &xhci->op_regs->cmd_ring); - xhci_write_64(xhci, temp_64 | CMD_RING_ABORT, - &xhci->op_regs->cmd_ring); + /* + * The control bits like command stop, abort are located in lower + * dword of the command ring control register. Limit the write + * to the lower dword to avoid corrupting the command ring pointer + * in case if the command ring is stopped by the time upper dword + * is written. + */ + temp_32 = readl(&xhci->op_regs->cmd_ring); + writel(temp_32 | CMD_RING_ABORT, &xhci->op_regs->cmd_ring); /* Section 4.6.1.2 of xHCI 1.0 spec says software should also time the * completion of the Command Abort operation. If CRR is not negated in 5