linux/arch/arm64/mm
Lorenzo Pieralisi 16c11325cc 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 722ec35f7f ("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>
2016-07-08 18:06:04 +01:00
..
cache.S arm64: fix "dc cvau" cache operation on errata-affected core 2016-07-01 11:26:20 +01:00
context.c arm64: Add cpu_panic_kernel helper 2016-04-15 18:06:06 +01:00
copypage.c arm64: Defer dcache flush in __cpu_copy_user_page 2015-12-17 11:07:13 +00:00
dma-mapping.c arm64: mm: change IOMMU notifier action to attach DMA ops 2016-07-08 18:06:04 +01:00
dump.c arm64: mm: dump: make page table dumping reusable 2016-06-21 15:09:11 +01:00
extable.c arm64: switch to relative exception tables 2016-02-24 14:57:26 +00:00
fault.c arm64: kill ESR_LNX_EXEC 2016-06-21 17:07:48 +01:00
flush.c arm64: mm: allow preemption in copy_to_user_page 2016-03-24 16:32:54 +00:00
hugetlbpage.c Revert "arm64: hugetlb: partial revert of 66b3923a1a0f" 2016-05-31 11:00:09 +01:00
init.c arm64: mm: fix location of _etext 2016-06-27 18:21:27 +01:00
ioremap.c arm64: add ioremap physical address information 2015-01-23 15:29:06 +00:00
kasan_init.c arm64: kasan: Fix zero shadow mapping overriding kernel image shadow 2016-03-11 11:03:35 +00:00
Makefile arm64, numa: Add NUMA support for arm64 platforms. 2016-04-15 18:06:09 +01:00
mm.h arm64: Move unflatten_device_tree() call earlier. 2016-04-15 18:06:08 +01:00
mmap.c arm64: mm: remove unnecessary EXPORT_SYMBOL_GPL 2016-05-05 09:49:38 +01:00
mmu.c arm64: mm: fold init_pgd() into __create_pgd_mapping() 2016-07-01 11:56:27 +01:00
numa.c arm64, numa: Add NUMA support for arm64 platforms. 2016-04-15 18:06:09 +01:00
pageattr.c arm64: Add support for ARCH_SUPPORTS_DEBUG_PAGEALLOC 2016-02-16 15:40:30 +00:00
pgd.c arm64: mm: move pgd_cache initialisation to pgtable_cache_init 2016-01-05 15:43:10 +00:00
proc.S arm64: Change cpu_resume() to enable mmu early then access sleep_sp by va 2016-04-28 12:05:46 +01:00