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* [PATCH v3] PCI: hosts: mark pcie/pci (msi) irq cascade handler as IRQF_NO_THREAD
@ 2015-12-10 19:18 Grygorii Strashko
  2016-01-06 22:18 ` Bjorn Helgaas
  2016-01-07  9:18 ` Lucas Stach
  0 siblings, 2 replies; 8+ messages in thread
From: Grygorii Strashko @ 2015-12-10 19:18 UTC (permalink / raw)
  To: Sebastian Andrzej Siewior, linux-pci, Bjorn Helgaas
  Cc: tony, nsekhar, linux-arm-kernel, linux-samsung-soc, linux-tegra,
	linux-sh, linux-omap, linux-kernel, Grygorii Strashko,
	Kishon Vijay Abraham I, Jingoo Han, Kukjin Kim,
	Krzysztof Kozlowski, Richard Zhu, Lucas Stach, Thierry Reding,
	Stephen Warren, Alexandre Courbot, Simon Horman, Pratyush Anand,
	Michal Simek, Sören Brinkmann

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@ti.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Kukjin Kim <kgene@kernel.org>
Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Cc: Richard Zhu <Richard.Zhu@freescale.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Simon Horman <horms@verge.net.au>
Cc: Pratyush Anand <pratyush.anand@gmail.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: "Sören Brinkmann" <soren.brinkmann@xilinx.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
---
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


^ permalink raw reply related	[flat|nested] 8+ messages in thread
end of thread, other threads:[~2016-01-15 18:31 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2015-12-10 19:18 [PATCH v3] PCI: hosts: mark pcie/pci (msi) irq cascade handler as IRQF_NO_THREAD Grygorii Strashko
2016-01-06 22:18 ` Bjorn Helgaas
2016-01-13 13:39   ` Sebastian Andrzej Siewior
2016-01-13 17:50     ` Bjorn Helgaas
2016-01-13 18:48       ` Grygorii Strashko
2016-01-14  6:19         ` Kishon Vijay Abraham I
2016-01-15 18:31           ` Bjorn Helgaas
2016-01-07  9:18 ` Lucas Stach

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