genirq/msi: Limit level-triggered MSI to platform devices

Marc Zyngier · KAGA-KOKO · commit 6988e0e0d283 · 2018-05-13T15:58:59.000+02:00
Nobody would be insane enough to try and use level triggered MSIs on PCI, but let's make sure it doesn't happen. Also, let's mandate that the irqchip backing the platform MSI domain is providing the IRQCHIP_SUPPORTS_LEVEL_MSI flag. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Rob Herring <robh@kernel.org> Cc: Jason Cooper <jason@lakedaemon.net> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com> Cc: Miquel Raynal <miquel.raynal@bootlin.com> Link: https://lkml.kernel.org/r/20180508121438.11301-3-marc.zyngier@arm.com
diff --git a/drivers/base/platform-msi.c b/drivers/base/platform-msi.c
@@ -101,6 +101,9 @@ static void platform_msi_update_chip_ops(struct msi_domain_info *info)
 		chip->irq_set_affinity = msi_domain_set_affinity;
 	if (!chip->irq_write_msi_msg)
 		chip->irq_write_msi_msg = platform_msi_write_msg;
+	if (WARN_ON((info->flags & MSI_FLAG_LEVEL_CAPABLE) &&
+		    !(chip->flags & IRQCHIP_SUPPORTS_LEVEL_MSI)))
+		info->flags &= ~MSI_FLAG_LEVEL_CAPABLE;
 }
 
 static void platform_msi_free_descs(struct device *dev, int base, int nvec)
diff --git a/drivers/bus/fsl-mc/fsl-mc-msi.c b/drivers/bus/fsl-mc/fsl-mc-msi.c
@@ -163,6 +163,8 @@ struct irq_domain *fsl_mc_msi_create_irq_domain(struct fwnode_handle *fwnode,
 {
 	struct irq_domain *domain;
 
+	if (WARN_ON((info->flags & MSI_FLAG_LEVEL_CAPABLE)))
+		info->flags &= ~MSI_FLAG_LEVEL_CAPABLE;
 	if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
 		fsl_mc_msi_update_dom_ops(info);
 	if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
@@ -1434,6 +1434,9 @@ struct irq_domain *pci_msi_create_irq_domain(struct fwnode_handle *fwnode,
 {
 	struct irq_domain *domain;
 
+	if (WARN_ON(info->flags & MSI_FLAG_LEVEL_CAPABLE))
+		info->flags &= ~MSI_FLAG_LEVEL_CAPABLE;
+
 	if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
 		pci_msi_domain_update_dom_ops(info);
 	if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
diff --git a/include/linux/irq.h b/include/linux/irq.h
@@ -512,6 +512,7 @@ enum {
 	IRQCHIP_SKIP_SET_WAKE		= (1 <<  4),
 	IRQCHIP_ONESHOT_SAFE		= (1 <<  5),
 	IRQCHIP_EOI_THREADED		= (1 <<  6),
+	IRQCHIP_SUPPORTS_LEVEL_MSI	= (1 <<  7),
 };
 
 #include <linux/irqdesc.h>

Original file line number	Diff line number	Diff line change
`@@ -101,6 +101,9 @@ static void platform_msi_update_chip_ops(struct msi_domain_info *info)`
`101`	`101`	`chip->irq_set_affinity = msi_domain_set_affinity;`
`102`	`102`	`if (!chip->irq_write_msi_msg)`
`103`	`103`	`chip->irq_write_msi_msg = platform_msi_write_msg;`
	`104`	`+ if (WARN_ON((info->flags & MSI_FLAG_LEVEL_CAPABLE) &&`
	`105`	`+ !(chip->flags & IRQCHIP_SUPPORTS_LEVEL_MSI)))`
	`106`	`+ info->flags &= ~MSI_FLAG_LEVEL_CAPABLE;`
`104`	`107`	`}`
`105`	`108`
`106`	`109`	`static void platform_msi_free_descs(struct device *dev, int base, int nvec)`
Original file line number	Diff line number	Diff line change
`@@ -163,6 +163,8 @@ struct irq_domain fsl_mc_msi_create_irq_domain(struct fwnode_handle fwnode,`
`163`	`163`	`{`
`164`	`164`	`struct irq_domain *domain;`
`165`	`165`
	`166`	`+ if (WARN_ON((info->flags & MSI_FLAG_LEVEL_CAPABLE)))`
	`167`	`+ info->flags &= ~MSI_FLAG_LEVEL_CAPABLE;`
`166`	`168`	`if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)`
`167`	`169`	`fsl_mc_msi_update_dom_ops(info);`
`168`	`170`	`if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)`
Original file line number	Diff line number	Diff line change
`@@ -1434,6 +1434,9 @@ struct irq_domain pci_msi_create_irq_domain(struct fwnode_handle fwnode,`
`1434`	`1434`	`{`
`1435`	`1435`	`struct irq_domain *domain;`
`1436`	`1436`
	`1437`	`+ if (WARN_ON(info->flags & MSI_FLAG_LEVEL_CAPABLE))`
	`1438`	`+ info->flags &= ~MSI_FLAG_LEVEL_CAPABLE;`
	`1439`	`+`
`1437`	`1440`	`if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)`
`1438`	`1441`	`pci_msi_domain_update_dom_ops(info);`
`1439`	`1442`	`if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)`