Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753348AbbLDPEO (ORCPT ); Fri, 4 Dec 2015 10:04:14 -0500 Received: from hqemgate14.nvidia.com ([216.228.121.143]:14392 "EHLO hqemgate14.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753900AbbLDPAX (ORCPT ); Fri, 4 Dec 2015 10:00:23 -0500 X-PGP-Universal: processed; by hqnvupgp07.nvidia.com on Fri, 04 Dec 2015 06:47:01 -0800 From: Jon Hunter To: Philipp Zabel , Stephen Warren , Thierry Reding , Alexandre Courbot , Rafael Wysocki , Kevin Hilman , Ulf Hansson , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala CC: Vince Hsu , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org, linux-pm@vger.kernel.org, Jon Hunter Subject: [PATCH V4 05/16] soc: tegra: pmc: Avoid extra remapping of PMC registers Date: Fri, 4 Dec 2015 14:57:06 +0000 Message-ID: <1449241037-22193-6-git-send-email-jonathanh@nvidia.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1449241037-22193-1-git-send-email-jonathanh@nvidia.com> References: <1449241037-22193-1-git-send-email-jonathanh@nvidia.com> X-NVConfidentiality: public MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2833 Lines: 78 During early initialisation, the PMC registers are mapped and the PMC SoC data is populated in the PMC data structure. This allows other drivers access the PMC register space, via the public tegra PMC APIs, prior to probing the PMC device. When the PMC device is probed, the PMC registers are mapped again and if successful the initial mapping is freed. If the probing of the PMC device fails after the registers are remapped, then the registers will be unmapped and hence the pointer to the PMC registers will be invalid. This could lead to a potential crash, because once the PMC SoC data pointer is populated, the driver assumes that the PMC register mapping is also valid and a user calling any of the public tegra PMC APIs could trigger an exception because these APIs don't check that the mapping is still valid. Rather than adding a test to see if the PMC register mapping is valid, fix this by removing the second mapping of the PMC registers and reserve the memory region for the PMC registers during early initialisation where the initial mapping is created. During the probing of the PMC simply check that the PMC registers have been mapped. Signed-off-by: Jon Hunter --- drivers/soc/tegra/pmc.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c index e60fc2d33c94..fdd1a8d0940f 100644 --- a/drivers/soc/tegra/pmc.c +++ b/drivers/soc/tegra/pmc.c @@ -807,22 +807,17 @@ out: static int tegra_pmc_probe(struct platform_device *pdev) { - void __iomem *base = pmc->base; - struct resource *res; int err; + if (!pmc->base) { + dev_err(&pdev->dev, "base address is not configured\n"); + return -ENXIO; + } + err = tegra_pmc_parse_dt(pmc, pdev->dev.of_node); if (err < 0) return err; - /* take over the memory region from the early initialization */ - res = platform_get_resource(pdev, IORESOURCE_MEM, 0); - pmc->base = devm_ioremap_resource(&pdev->dev, res); - if (IS_ERR(pmc->base)) - return PTR_ERR(pmc->base); - - iounmap(base); - pmc->clk = devm_clk_get(&pdev->dev, "pclk"); if (IS_ERR(pmc->clk)) { err = PTR_ERR(pmc->clk); @@ -1126,8 +1121,12 @@ static int __init tegra_pmc_early_init(void) pmc->soc = match->data; } + if (!request_mem_region(regs.start, resource_size(®s), regs.name)) + return -ENOMEM; + pmc->base = ioremap_nocache(regs.start, resource_size(®s)); if (!pmc->base) { + release_mem_region(regs.start, resource_size(®s)); pr_err("failed to map PMC registers\n"); return -ENXIO; } -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/