From patchwork Wed Nov 28 13:25:54 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Agner X-Patchwork-Id: 1004545 X-Patchwork-Delegate: lorenzo.pieralisi@arm.com Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-pci-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=agner.ch Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=agner.ch header.i=@agner.ch header.b="SSWaLxnX"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 434hHX1XQjz9s2P for ; Thu, 29 Nov 2018 00:26:00 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728031AbeK2A1h (ORCPT ); Wed, 28 Nov 2018 19:27:37 -0500 Received: from mail.kmu-office.ch ([178.209.48.109]:41852 "EHLO mail.kmu-office.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728023AbeK2A1h (ORCPT ); Wed, 28 Nov 2018 19:27:37 -0500 Received: from trochilidae.toradex.int (unknown [46.140.72.82]) by mail.kmu-office.ch (Postfix) with ESMTPSA id 9BEFA5C0D8F; Wed, 28 Nov 2018 14:25:56 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=agner.ch; s=dkim; t=1543411556; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type: content-transfer-encoding:content-transfer-encoding:in-reply-to: references; bh=kmrYbWTrsnLX4BVniuahhuRxXCpcWsRxae9zHzOhLKc=; b=SSWaLxnXQpBhGX96ZBuORbwQFgLcAsufpY+nbboGT0yGtRq1HDecRGy/TWrnGXpFU5EOAu rqAz9PnIHtXuw9/iojnpEaJQhSgxyVAcX5T+lIsvkdOSW8QwfucuvaKT/uiUHp7bTOTEMw 9T6B3J1MBoJH7f5/HCO2QJy1xriV8oQ= From: Stefan Agner To: hongxing.zhu@nxp.com, l.stach@pengutronix.de Cc: leonard.crestez@nxp.com, andrew.smirnov@gmail.com, festevam@gmail.com, lorenzo.pieralisi@arm.com, tpiepho@impinj.com, bhelgaas@google.com, stefan@agner.ch, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH] pci: imx6: support kernels built in Thumb-2 mode Date: Wed, 28 Nov 2018 14:25:54 +0100 Message-Id: <20181128132554.28139-1-stefan@agner.ch> X-Mailer: git-send-email 2.19.1 MIME-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Add a fault handler which handles reads in Thumb-2 mode. Install the appropriate handler depending on which mode the kernel has been built. This avoids an "Unhandled fault: external abort on non-linefetch (0x1008) at 0xf0a80000" during boot on a device with a PCIe switch connected. Link: https://lore.kernel.org/linux-pci/20181126161645.8177-1-stefan@agner.ch/ Signed-off-by: Stefan Agner --- FWIW, I found this manual helpful to write the code below: http://hermes.wings.cs.wisc.edu/files/Thumb-2SupplementReferenceManual.pdf#page=43&zoom=100,0,66 -- Stefan drivers/pci/controller/dwc/pci-imx6.c | 37 ++++++++++++++++++++++++++- 1 file changed, 36 insertions(+), 1 deletion(-) diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c index 69f86234f7c0..683deb74d69f 100644 --- a/drivers/pci/controller/dwc/pci-imx6.c +++ b/drivers/pci/controller/dwc/pci-imx6.c @@ -29,6 +29,7 @@ #include #include #include +#include #include "pcie-designware.h" @@ -299,6 +300,37 @@ static int imx6q_pcie_abort_handler(unsigned long addr, return 1; } +static int imx6q_pcie_abort_handler_thumb2(unsigned long addr, + unsigned int fsr, struct pt_regs *regs) +{ + unsigned long pc = instruction_pointer(regs); + unsigned long instr = *(unsigned long *)pc; + unsigned long thumb2_instr = __mem_to_opcode_thumb16(instr); + int reg = thumb2_instr & 7; + + if (!__opcode_is_thumb16(instr & 0x0000ffffUL)) + return 1; + + /* Load word/byte and halfword immediate offset */ + if (((thumb2_instr & 0xe800) == 0x6800) || + ((thumb2_instr & 0xf800) == 0x8800)) { + unsigned long val; + + if (thumb2_instr & 0x1000) + val = 0xff; + else if (thumb2_instr & 0x8000) + val = 0xffff; + else + val = 0xffffffffUL; + + regs->uregs[reg] = val; + regs->ARM_pc += 2; + return 0; + } + + return 1; +} + static int imx6_pcie_attach_pd(struct device *dev) { struct imx6_pcie *imx6_pcie = dev_get_drvdata(dev); @@ -1069,6 +1101,8 @@ static struct platform_driver imx6_pcie_driver = { static int __init imx6_pcie_init(void) { + bool thumb2 = IS_ENABLED(CONFIG_THUMB2_KERNEL); + /* * Since probe() can be deferred we need to make sure that * hook_fault_code is not called after __init memory is freed @@ -1076,7 +1110,8 @@ static int __init imx6_pcie_init(void) * we can install the handler here without risking it * accessing some uninitialized driver state. */ - hook_fault_code(8, imx6q_pcie_abort_handler, SIGBUS, 0, + hook_fault_code(8, thumb2 ? imx6q_pcie_abort_handler_thumb2 : + imx6q_pcie_abort_handler, SIGBUS, 0, "external abort on non-linefetch"); return platform_driver_register(&imx6_pcie_driver);