Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1283904

[PATCH V4 05/16] soc: tegra: pmc: Avoid extra remapping of PMC registers

Show all headers | View raw

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 <jonathanh@nvidia.com>
---
 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(&regs), regs.name))
+		return -ENOMEM;
+
 	pmc->base = ioremap_nocache(regs.start, resource_size(&regs));
 	if (!pmc->base) {
+		release_mem_region(regs.start, resource_size(&regs));
 		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/

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH V4 00/16] Add generic PM domain support for Tegra Jon Hunter <jonathanh@nvidia.com> - 2015-12-04 16:10 +0100
  [PATCH V4 02/16] soc: tegra: pmc: Add missing structure members to kernel-doc Jon Hunter <jonathanh@nvidia.com> - 2015-12-04 16:10 +0100
  [PATCH V4 12/16] Documentation: DT: bindings: Add power domain info for NVIDIA PMC Jon Hunter <jonathanh@nvidia.com> - 2015-12-04 16:10 +0100
    Re: [PATCH V4 12/16] Documentation: DT: bindings: Add power domain  info for NVIDIA PMC Rob Herring <robh@kernel.org> - 2015-12-06 01:40 +0100
      Re: [PATCH V4 12/16] Documentation: DT: bindings: Add power domain  info for NVIDIA PMC Jon Hunter <jonathanh@nvidia.com> - 2015-12-07 11:00 +0100
    Re: [PATCH V4 12/16] Documentation: DT: bindings: Add power domain info for NVIDIA PMC Kevin Hilman <khilman@kernel.org> - 2015-12-08 20:10 +0100
      Re: [PATCH V4 12/16] Documentation: DT: bindings: Add power domain  info for NVIDIA PMC Jon Hunter <jonathanh@nvidia.com> - 2015-12-09 13:30 +0100
        Re: [PATCH V4 12/16] Documentation: DT: bindings: Add power domain  info for NVIDIA PMC Jon Hunter <jonathanh@nvidia.com> - 2015-12-09 13:40 +0100
  [PATCH V4 07/16] soc: tegra: pmc: Remove non-existing power partitions for T210 Jon Hunter <jonathanh@nvidia.com> - 2015-12-04 16:10 +0100
  [PATCH V4 06/16] soc: tegra: pmc: Wait for powergate state to change Jon Hunter <jonathanh@nvidia.com> - 2015-12-04 16:10 +0100
  [PATCH V4 05/16] soc: tegra: pmc: Avoid extra remapping of PMC registers Jon Hunter <jonathanh@nvidia.com> - 2015-12-04 16:10 +0100
  [PATCH V4 10/16] PM / Domains: Add function to remove a pm-domain Jon Hunter <jonathanh@nvidia.com> - 2015-12-04 16:10 +0100
  [PATCH V4 16/16] ARM64: tegra: select PM_GENERIC_DOMAINS Jon Hunter <jonathanh@nvidia.com> - 2015-12-04 16:10 +0100
  [PATCH V4 13/16] soc: tegra: pmc: Add generic PM domain support Jon Hunter <jonathanh@nvidia.com> - 2015-12-04 16:10 +0100
  [PATCH V4 08/16] soc: tegra: pmc: Fix checking of valid partitions Jon Hunter <jonathanh@nvidia.com> - 2015-12-04 16:10 +0100
  [PATCH V4 01/16] reset: add of_reset_control_get_by_index() Jon Hunter <jonathanh@nvidia.com> - 2015-12-04 16:10 +0100

csiph-web