On -RT and if kernel is booting with "threadirqs" cmd line parameter pcie/pci (msi) irq cascade handlers (like dra7xx_pcie_msi_irq_handler()) will be forced threaded and, as result, will generate warnings like: WARNING: CPU: 1 PID: 82 at kernel/irq/handle.c:150 handle_irq_event_percpu+0x14c/0x174() irq 460 handler irq_default_primary_handler+0x0/0x14 enabled interrupts Backtrace: (warn_slowpath_common) from [<c0043758>] (warn_slowpath_fmt+0x38/0x40) (warn_slowpath_fmt) from [<c0085fd0>] (handle_irq_event_percpu+0x14c/0x174) (handle_irq_event_percpu) from [<c008607c>] (handle_irq_event+0x84/0xb8) (handle_irq_event) from [<c0089240>] (handle_simple_irq+0x90/0x118) (handle_simple_irq) from [<c0085514>] (generic_handle_irq+0x30/0x44) (generic_handle_irq) from [<c034a7d4>] (dra7xx_pcie_msi_irq_handler+0x7c/0x8c) (dra7xx_pcie_msi_irq_handler) from [<c0086f08>] (irq_forced_thread_fn+0x28/0x5c) (irq_forced_thread_fn) from [<c00871dc>] (irq_thread+0x128/0x204) This happens because all of them invoke generic_handle_irq() from the requsted handler. generic_handle_irq grabs raw_locks and this needs to run in raw-irq context. This issue was originally reproduced on TI dra7-evem, but, as was identified during dicussion [1], other PCI(e) hosts can also suffer from this issue. So let's fix all them at once and mark pcie/pci (msi) irq cascade handlers IRQF_NO_THREAD explicitly. [1] https://lkml.org/lkml/2015/11/20/356 Cc: Kishon Vijay Abraham I <kishon@xxxxxx> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> Cc: Jingoo Han <jingoohan1@xxxxxxxxx> Cc: Kukjin Kim <kgene@xxxxxxxxxx> Cc: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx> Cc: Richard Zhu <Richard.Zhu@xxxxxxxxxxxxx> Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx> Cc: Thierry Reding <thierry.reding@xxxxxxxxx> Cc: Stephen Warren <swarren@xxxxxxxxxxxxx> Cc: Alexandre Courbot <gnurou@xxxxxxxxx> Cc: Simon Horman <horms@xxxxxxxxxxxx> Cc: Pratyush Anand <pratyush.anand@xxxxxxxxx> Cc: Michal Simek <michal.simek@xxxxxxxxxx> Cc: "Sören Brinkmann" <soren.brinkmann@xxxxxxxxxx> Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx> --- Changes in v3: - change applied to all affected pci(e) host drivers in drivers/pci/hosts. After some invsetigation I've decided to not touch arch code - it is not easy to identify all places which need to be fixed. if it's still required - i can send separate patches for arch/mips/pci/msi-octeon.c and arch/sparc/kernel/pci_msi.c. Links v2: https://lkml.org/lkml/2015/11/20/356 v1: https://lkml.org/lkml/2015/11/5/593 ref: https://lkml.org/lkml/2015/11/3/660 drivers/pci/host/pci-dra7xx.c | 13 ++++++++++++- drivers/pci/host/pci-exynos.c | 3 ++- drivers/pci/host/pci-imx6.c | 3 ++- drivers/pci/host/pci-tegra.c | 2 +- drivers/pci/host/pcie-rcar.c | 6 ++++-- drivers/pci/host/pcie-spear13xx.c | 3 ++- drivers/pci/host/pcie-xilinx.c | 3 ++- 7 files changed, 25 insertions(+), 8 deletions(-) diff --git a/drivers/pci/host/pci-dra7xx.c b/drivers/pci/host/pci-dra7xx.c index 8c36880..0415192 100644 --- a/drivers/pci/host/pci-dra7xx.c +++ b/drivers/pci/host/pci-dra7xx.c @@ -301,8 +301,19 @@ static int __init dra7xx_add_pcie_port(struct dra7xx_pcie *dra7xx, return -EINVAL; } + /* + * Mark dra7xx_pcie_msi IRQ as IRQF_NO_THREAD + * On -RT and if kernel is booting with "threadirqs" cmd line parameter + * the dra7xx_pcie_msi_irq_handler() will be forced threaded but, + * in the same time, it's IRQ dispatcher and calls generic_handle_irq(), + * which, in turn, will be resolved to handle_simple_irq() call. + * The handle_simple_irq() expected to be called with IRQ disabled, as + * result kernle will display warning: + * "irq XXX handler YYY+0x0/0x14 enabled interrupts". + */ ret = devm_request_irq(&pdev->dev, pp->irq, - dra7xx_pcie_msi_irq_handler, IRQF_SHARED, + dra7xx_pcie_msi_irq_handler, + IRQF_SHARED | IRQF_NO_THREAD, "dra7-pcie-msi", pp); if (ret) { dev_err(&pdev->dev, "failed to request irq\n"); diff --git a/drivers/pci/host/pci-exynos.c b/drivers/pci/host/pci-exynos.c index 01095e1..d997d22 100644 --- a/drivers/pci/host/pci-exynos.c +++ b/drivers/pci/host/pci-exynos.c @@ -522,7 +522,8 @@ static int __init exynos_add_pcie_port(struct pcie_port *pp, ret = devm_request_irq(&pdev->dev, pp->msi_irq, exynos_pcie_msi_irq_handler, - IRQF_SHARED, "exynos-pcie", pp); + IRQF_SHARED | IRQF_NO_THREAD, + "exynos-pcie", pp); if (ret) { dev_err(&pdev->dev, "failed to request msi irq\n"); return ret; diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c index 22e8224..9ce7cd1 100644 --- a/drivers/pci/host/pci-imx6.c +++ b/drivers/pci/host/pci-imx6.c @@ -537,7 +537,8 @@ static int __init imx6_add_pcie_port(struct pcie_port *pp, ret = devm_request_irq(&pdev->dev, pp->msi_irq, imx6_pcie_msi_handler, - IRQF_SHARED, "mx6-pcie-msi", pp); + IRQF_SHARED | IRQF_NO_THREAD, + "mx6-pcie-msi", pp); if (ret) { dev_err(&pdev->dev, "failed to request MSI irq\n"); return ret; diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c index 3018ae5..3032311 100644 --- a/drivers/pci/host/pci-tegra.c +++ b/drivers/pci/host/pci-tegra.c @@ -1288,7 +1288,7 @@ static int tegra_pcie_enable_msi(struct tegra_pcie *pcie) msi->irq = err; - err = request_irq(msi->irq, tegra_pcie_msi_irq, 0, + err = request_irq(msi->irq, tegra_pcie_msi_irq, IRQF_NO_THREAD, tegra_msi_irq_chip.name, pcie); if (err < 0) { dev_err(&pdev->dev, "failed to request IRQ: %d\n", err); diff --git a/drivers/pci/host/pcie-rcar.c b/drivers/pci/host/pcie-rcar.c index f4fa6c5..414c336 100644 --- a/drivers/pci/host/pcie-rcar.c +++ b/drivers/pci/host/pcie-rcar.c @@ -720,14 +720,16 @@ static int rcar_pcie_enable_msi(struct rcar_pcie *pcie) /* Two irqs are for MSI, but they are also used for non-MSI irqs */ err = devm_request_irq(&pdev->dev, msi->irq1, rcar_pcie_msi_irq, - IRQF_SHARED, rcar_msi_irq_chip.name, pcie); + IRQF_SHARED | IRQF_NO_THREAD, + rcar_msi_irq_chip.name, pcie); if (err < 0) { dev_err(&pdev->dev, "failed to request IRQ: %d\n", err); goto err; } err = devm_request_irq(&pdev->dev, msi->irq2, rcar_pcie_msi_irq, - IRQF_SHARED, rcar_msi_irq_chip.name, pcie); + IRQF_SHARED | IRQF_NO_THREAD, + rcar_msi_irq_chip.name, pcie); if (err < 0) { dev_err(&pdev->dev, "failed to request IRQ: %d\n", err); goto err; diff --git a/drivers/pci/host/pcie-spear13xx.c b/drivers/pci/host/pcie-spear13xx.c index b95b756..a6cd823 100644 --- a/drivers/pci/host/pcie-spear13xx.c +++ b/drivers/pci/host/pcie-spear13xx.c @@ -279,7 +279,8 @@ static int spear13xx_add_pcie_port(struct pcie_port *pp, return -ENODEV; } ret = devm_request_irq(dev, pp->irq, spear13xx_pcie_irq_handler, - IRQF_SHARED, "spear1340-pcie", pp); + IRQF_SHARED | IRQF_NO_THREAD, + "spear1340-pcie", pp); if (ret) { dev_err(dev, "failed to request irq %d\n", pp->irq); return ret; diff --git a/drivers/pci/host/pcie-xilinx.c b/drivers/pci/host/pcie-xilinx.c index 3c7a0d5..4cfa463 100644 --- a/drivers/pci/host/pcie-xilinx.c +++ b/drivers/pci/host/pcie-xilinx.c @@ -781,7 +781,8 @@ static int xilinx_pcie_parse_dt(struct xilinx_pcie_port *port) port->irq = irq_of_parse_and_map(node, 0); err = devm_request_irq(dev, port->irq, xilinx_pcie_intr_handler, - IRQF_SHARED, "xilinx-pcie", port); + IRQF_SHARED | IRQF_NO_THREAD, + "xilinx-pcie", port); if (err) { dev_err(dev, "unable to request irq %d\n", port->irq); return err; -- 2.6.4 -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
