diff options
author | Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> | 2016-07-01 19:50:10 +0300 |
---|---|---|
committer | Catalin Marinas <catalin.marinas@arm.com> | 2016-07-08 20:06:04 +0300 |
commit | 16c11325cc44f0614a45e584d439e195059c3f5a (patch) | |
tree | 627f73411c416acee852480df7f88f228e7dfe49 /arch/arm64 | |
parent | 19a469a58720ea96b649b06fb09ddfd3e831aa69 (diff) | |
download | linux-16c11325cc44f0614a45e584d439e195059c3f5a.tar.xz |
arm64: mm: change IOMMU notifier action to attach DMA ops
Current bus notifier in ARM64 (__iommu_attach_notifier)
attempts to attach dma_ops to a device on BUS_NOTIFY_ADD_DEVICE
action notification.
This will cause issues on ACPI based systems, where PCI devices
can be added before the IOMMUs the devices are attached to
had a chance to be probed, causing failures on attempts to
attach dma_ops in that the domain for the respective IOMMU
may not be set-up yet by the time the bus notifier is run.
Devices dma_ops do not require to be set-up till the matching
device drivers are probed. This means that instead of running
the notifier attaching dma_ops to devices (__iommu_attach_notifier)
on BUS_NOTIFY_ADD_DEVICE action, it can be run just before the
device driver is bound to the device in question (on action
BUS_NOTIFY_BIND_DRIVER) so that it is certain that its IOMMU
group and domain are set-up accordingly at the time the
notifier is triggered.
This patch changes the notifier action upon which dma_ops
are attached to devices and defer it to driver binding time,
so that IOMMU devices have a chance to be probed and to register
their bus notifiers before the dma_ops attach sequence for a
device is actually carried out.
As a result we also no longer need worry about racing with
iommu_bus_notifier(), or about retrying the queue in case devices
were added too early on DT-based systems, so clean up the notifier
itself plus the additional workaround from 722ec35f7fae ("arm64:
dma-mapping: fix handling of devices registered before arch_initcall")
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
[rm: get rid of other now-redundant bits]
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64')
-rw-r--r-- | arch/arm64/mm/dma-mapping.c | 22 |
1 files changed, 5 insertions, 17 deletions
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c index 46a4157adc17..f6c55afab3e2 100644 --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -861,15 +861,16 @@ static int __iommu_attach_notifier(struct notifier_block *nb, { struct iommu_dma_notifier_data *master, *tmp; - if (action != BUS_NOTIFY_ADD_DEVICE) + if (action != BUS_NOTIFY_BIND_DRIVER) return 0; mutex_lock(&iommu_dma_notifier_lock); list_for_each_entry_safe(master, tmp, &iommu_dma_masters, list) { - if (do_iommu_attach(master->dev, master->ops, - master->dma_base, master->size)) { + if (data == master->dev && do_iommu_attach(master->dev, + master->ops, master->dma_base, master->size)) { list_del(&master->list); kfree(master); + break; } } mutex_unlock(&iommu_dma_notifier_lock); @@ -883,17 +884,8 @@ static int __init register_iommu_dma_ops_notifier(struct bus_type *bus) if (!nb) return -ENOMEM; - /* - * The device must be attached to a domain before the driver probe - * routine gets a chance to start allocating DMA buffers. However, - * the IOMMU driver also needs a chance to configure the iommu_group - * via its add_device callback first, so we need to make the attach - * happen between those two points. Since the IOMMU core uses a bus - * notifier with default priority for add_device, do the same but - * with a lower priority to ensure the appropriate ordering. - */ + nb->notifier_call = __iommu_attach_notifier; - nb->priority = -100; ret = bus_register_notifier(bus, nb); if (ret) { @@ -917,10 +909,6 @@ static int __init __iommu_dma_init(void) if (!ret) ret = register_iommu_dma_ops_notifier(&pci_bus_type); #endif - - /* handle devices queued before this arch_initcall */ - if (!ret) - __iommu_attach_notifier(NULL, BUS_NOTIFY_ADD_DEVICE, NULL); return ret; } arch_initcall(__iommu_dma_init); |