[SRU][F][PATCH 0/1] Backport "iommu/arm-smmu-v3: Don't reserve implementation defined register space"

[Magali Lemes]

BugLink: https://bugs.launchpad.net/bugs/2067864

[Impact]
With certain bare-metal ARM instance types running the 5.4 kernels, there is a
conflict error during the ioremap operation while loading the ARM SMMUv3
driver, causing boot issues.
This can be solved by backporting upstream commit 52f3fab0067d
("iommu/arm-smmu-v3: Don't reserve implementation defined register space").

[Fix]
There was a conflict when adding arm_smmu_ioremap() due to the current
context missing ab246774713e ("iommu/arm-smmu-v3: Unregister IOMMU and
bus ops on device removal").

[Test]
Compiled and boot tested.
It's been further tested by the bug reporter that the bare-metal ARM instance
running a 5.4 kernel with this patch applied can boot.

[Where problems could occur]
This touches probing of the ARM SMMUv3 driver, which might lead to boot
failures or system instability.

[Other info]
This has been initially submitted for the F:linux-aws kernel, but since this
issue can happen on other similar hardware configurations, it makes sense to
target the generic kernel as well.

Jean-Philippe Brucker (1):
  iommu/arm-smmu-v3: Don't reserve implementation defined register space

 drivers/iommu/arm-smmu-v3.c | 35 +++++++++++++++++++++++++++++++----
 1 file changed, 31 insertions(+), 4 deletions(-)

-- 
2.34.1