Commit c13dbc1e authored by Robin Murphy's avatar Robin Murphy Committed by Joerg Roedel
Browse files

iommu: Always register bus notifiers 



The number of bus types that the IOMMU subsystem deals with is small and
manageable, so pull that list into core code as a first step towards
cleaning up all the boilerplate bus-awareness from drivers. Calling
iommu_probe_device() before bus->iommu_ops is set will simply return
-ENODEV and not break the notifier call chain, so there should be no
harm in proactively registering all our bus notifiers at init time.

Tested-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Matthew Rosato <mjrosato@linux.ibm.com> # s390
Tested-by: Niklas Schnelle <schnelle@linux.ibm.com> # s390
Signed-off-by: default avatarRobin Murphy <robin.murphy@arm.com>
Reviewed-by: default avatarKevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/7462347bf938bd6eedb629a3a318434f6516e712.1660572783.git.robin.murphy@arm.com


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent 927a5fdd

drivers/iommu/iommu.c

+37 −35
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 


#define pr_fmt(fmt)    "iommu: " fmt



#include <linux/amba/bus.h>

#include <linux/device.h>

#include <linux/dma-iommu.h>

#include <linux/kernel.h>
@@ -16,11 +17,13 @@ 
#include <linux/export.h>

#include <linux/slab.h>

#include <linux/errno.h>

#include <linux/host1x_context_bus.h>

#include <linux/iommu.h>

#include <linux/idr.h>

#include <linux/err.h>

#include <linux/pci.h>

#include <linux/bitops.h>

#include <linux/platform_device.h>

#include <linux/property.h>

#include <linux/fsl/mc.h>

#include <linux/module.h>
@@ -75,6 +78,8 @@ static const char * const iommu_group_resv_type_string[] = { 
#define IOMMU_CMD_LINE_DMA_API		BIT(0)

#define IOMMU_CMD_LINE_STRICT		BIT(1)



static int iommu_bus_notifier(struct notifier_block *nb,

			      unsigned long action, void *data);

static int iommu_alloc_default_domain(struct iommu_group *group,

				      struct device *dev);

static struct iommu_domain *__iommu_domain_alloc(struct bus_type *bus,
@@ -103,6 +108,22 @@ struct iommu_group_attribute iommu_group_attr_##_name = \ 
static LIST_HEAD(iommu_device_list);

static DEFINE_SPINLOCK(iommu_device_lock);



static struct bus_type * const iommu_buses[] = {

	&platform_bus_type,

#ifdef CONFIG_PCI

	&pci_bus_type,

#endif

#ifdef CONFIG_ARM_AMBA

	&amba_bustype,

#endif

#ifdef CONFIG_FSL_MC_BUS

	&fsl_mc_bus_type,

#endif

#ifdef CONFIG_TEGRA_HOST1X_CONTEXT_BUS

	&host1x_context_device_bus_type,

#endif

};



/*

 * Use a function instead of an array here because the domain-type is a

 * bit-field, so an array would waste memory.
@@ -126,6 +147,8 @@ static const char *iommu_domain_type_str(unsigned int t) 


static int __init iommu_subsys_init(void)

{

	struct notifier_block *nb;



	if (!(iommu_cmd_line & IOMMU_CMD_LINE_DMA_API)) {

		if (IS_ENABLED(CONFIG_IOMMU_DEFAULT_PASSTHROUGH))

			iommu_set_default_passthrough(false);
@@ -152,6 +175,15 @@ static int __init iommu_subsys_init(void) 
			(iommu_cmd_line & IOMMU_CMD_LINE_STRICT) ?

				"(set via kernel command line)" : "");



	nb = kcalloc(ARRAY_SIZE(iommu_buses), sizeof(*nb), GFP_KERNEL);

	if (!nb)

		return -ENOMEM;



	for (int i = 0; i < ARRAY_SIZE(iommu_buses); i++) {

		nb[i].notifier_call = iommu_bus_notifier;

		bus_register_notifier(iommu_buses[i], &nb[i]);

	}



	return 0;

}

subsys_initcall(iommu_subsys_init);
@@ -1774,39 +1806,6 @@ int bus_iommu_probe(struct bus_type *bus) 
	return ret;

}



static int iommu_bus_init(struct bus_type *bus, const struct iommu_ops *ops)

{

	struct notifier_block *nb;

	int err;



	nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);

	if (!nb)

		return -ENOMEM;



	nb->notifier_call = iommu_bus_notifier;



	err = bus_register_notifier(bus, nb);

	if (err)

		goto out_free;



	err = bus_iommu_probe(bus);

	if (err)

		goto out_err;





	return 0;



out_err:

	/* Clean up */

	bus_for_each_dev(bus, NULL, NULL, remove_iommu_group);

	bus_unregister_notifier(bus, nb);



out_free:

	kfree(nb);



	return err;

}



/**

 * bus_set_iommu - set iommu-callbacks for the bus

 * @bus: bus.
@@ -1835,9 +1834,12 @@ int bus_set_iommu(struct bus_type *bus, const struct iommu_ops *ops) 
	bus->iommu_ops = ops;



	/* Do IOMMU specific setup for this bus-type */

	err = iommu_bus_init(bus, ops);

	if (err)

	err = bus_iommu_probe(bus);

	if (err) {

		/* Clean up */

		bus_for_each_dev(bus, NULL, NULL, remove_iommu_group);

		bus->iommu_ops = NULL;

	}



	return err;

}