linux-toradex.git/kernel/dma/mapping.c, branch v6.0-rc1

dma-mapping: reformat comment to suppress htmldoc warning

2022-07-28T14:21:33+00:00

make html doc reports a cryptic warning with the commit named below:

  kernel/dma/mapping.c:258: WARNING: Option list ends without a blank
                                     line; unexpected unindent.

Seems the parser is a bit fussy about the tabbing and having a single
space tab causes the warning. To suppress the warning add another
tab to the list and reindent everything.

Fixes: 7c2645a2a30a ("dma-mapping: allow EREMOTEIO return code for P2PDMA transfers")
Signed-off-by: Logan Gunthorpe 
Signed-off-by: Christoph Hellwig

dma-mapping: add flags to dma_map_ops to indicate PCI P2PDMA support

2022-07-26T11:27:48+00:00

Add a flags member to the dma_map_ops structure with one flag to
indicate support for PCI P2PDMA.

Also, add a helper to check if a device supports PCI P2PDMA.

Signed-off-by: Logan Gunthorpe 
Reviewed-by: Jason Gunthorpe 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Christoph Hellwig

dma-mapping: allow EREMOTEIO return code for P2PDMA transfers

2022-07-26T11:27:47+00:00

Add EREMOTEIO error return to dma_map_sgtable() which will be used
by .map_sg() implementations that detect P2PDMA pages that the
underlying DMA device cannot access.

Signed-off-by: Logan Gunthorpe 
Reviewed-by: Jason Gunthorpe 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Christoph Hellwig

dma-mapping: add dma_opt_mapping_size()

2022-07-19T04:05:41+00:00

Streaming DMA mapping involving an IOMMU may be much slower for larger
total mapping size. This is because every IOMMU DMA mapping requires an
IOVA to be allocated and freed. IOVA sizes above a certain limit are not
cached, which can have a big impact on DMA mapping performance.

Provide an API for device drivers to know this "optimal" limit, such that
they may try to produce mapping which don't exceed it.

Signed-off-by: John Garry 
Reviewed-by: Damien Le Moal 
Acked-by: Martin K. Petersen 
Signed-off-by: Christoph Hellwig

dma-mapping: move pgprot_decrypted out of dma_pgprot

2022-04-01T04:46:51+00:00

pgprot_decrypted is used by AMD SME systems to allow access to memory
that was set to not encrypted using set_memory_decrypted.  That only
happens for dma-direct memory as the IOMMU solves the addressing
challenges for the encryption bit using its own remapping.

Move the pgprot_decrypted call out of dma_pgprot which is also used
by the IOMMU mappings and into dma-direct so that it is only used with
memory that was set decrypted.

Fixes: f5ff79fddf0e ("dma-mapping: remove CONFIG_DMA_REMAP")
Reported-by: Alex Xu (Hello71) 
Signed-off-by: Christoph Hellwig 
Tested-by: Alex Xu (Hello71)

ARM: ixp4xx: Drop custom DMA coherency and bouncing

2022-02-12T17:20:04+00:00

The new PCI driver does not need any of this stuff, so just
drop it.

Cc: iommu@lists.linux-foundation.org
Reviewed-by: Christoph Hellwig 
Signed-off-by: Linus Walleij 
Link: https://lore.kernel.org/r/20220211223238.648934-12-linus.walleij@linaro.org
Signed-off-by: Linus Walleij

Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

2021-11-01T23:33:53+00:00

Pull arm64 updates from Will Deacon:
 "There's the usual summary below, but the highlights are support for
  the Armv8.6 timer extensions, KASAN support for asymmetric MTE, the
  ability to kexec() with the MMU enabled and a second attempt at
  switching to the generic pfn_valid() implementation.

  Summary:

   - Support for the Arm8.6 timer extensions, including a
     self-synchronising view of the system registers to elide some
     expensive ISB instructions.

   - Exception table cleanup and rework so that the fixup handlers
     appear correctly in backtraces.

   - A handful of miscellaneous changes, the main one being selection of
     CONFIG_HAVE_POSIX_CPU_TIMERS_TASK_WORK.

   - More mm and pgtable cleanups.

   - KASAN support for "asymmetric" MTE, where tag faults are reported
     synchronously for loads (via an exception) and asynchronously for
     stores (via a register).

   - Support for leaving the MMU enabled during kexec relocation, which
     significantly speeds up the operation.

   - Minor improvements to our perf PMU drivers.

   - Improvements to the compat vDSO build system, particularly when
     building with LLVM=1.

   - Preparatory work for handling some Coresight TRBE tracing errata.

   - Cleanup and refactoring of the SVE code to pave the way for SME
     support in future.

   - Ensure SCS pages are unpoisoned immediately prior to freeing them
     when KASAN is enabled for the vmalloc area.

   - Try moving to the generic pfn_valid() implementation again now that
     the DMA mapping issue from last time has been resolved.

   - Numerous improvements and additions to our FPSIMD and SVE
     selftests"

[ armv8.6 timer updates were in a shared branch and already came in
  through -tip in the timer pull  - Linus ]

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (85 commits)
  arm64: Select POSIX_CPU_TIMERS_TASK_WORK
  arm64: Document boot requirements for FEAT_SME_FA64
  arm64/sve: Fix warnings when SVE is disabled
  arm64/sve: Add stub for sve_max_virtualisable_vl()
  arm64: errata: Add detection for TRBE write to out-of-range
  arm64: errata: Add workaround for TSB flush failures
  arm64: errata: Add detection for TRBE overwrite in FILL mode
  arm64: Add Neoverse-N2, Cortex-A710 CPU part definition
  selftests: arm64: Factor out utility functions for assembly FP tests
  arm64: vmlinux.lds.S: remove `.fixup` section
  arm64: extable: add load_unaligned_zeropad() handler
  arm64: extable: add a dedicated uaccess handler
  arm64: extable: add `type` and `data` fields
  arm64: extable: use `ex` for `exception_table_entry`
  arm64: extable: make fixup_exception() return bool
  arm64: extable: consolidate definitions
  arm64: gpr-num: support W registers
  arm64: factor out GPR numbering helpers
  arm64: kvm: use kvm_exception_table_entry
  arm64: lib: __arch_copy_to_user(): fold fixups into body
  ...

dma-debug: teach add_dma_entry() about DMA_ATTR_SKIP_CPU_SYNC

2021-10-18T10:46:45+00:00

Mapping something twice should be possible as long as,
DMA_ATTR_SKIP_CPU_SYNC is passed to the strictly speaking second relevant
mapping operation (that attempts to map the same thing). So, don't issue a
warning if the specified condition is met in add_dma_entry().

Signed-off-by: Hamza Mahfooz 
Signed-off-by: Christoph Hellwig

dma-mapping: fix the kerneldoc for dma_map_sgtable()

2021-10-11T11:43:04+00:00

htmldocs began producing the following warnings:

  kernel/dma/mapping.c:256: WARNING: Definition list ends without a
             blank line; unexpected unindent.
  kernel/dma/mapping.c:257: WARNING: Bullet list ends without a blank
             line; unexpected unindent.

Reformatting the list without hyphens fixes the warnings and produces
both a readable text and HTML output.

Fixes: fffe3cc8c219 ("dma-mapping: allow map_sg() ops to return negative error code")
Reported-by: Stephen Rothwell 
Signed-off-by: Logan Gunthorpe 
Signed-off-by: Christoph Hellwig

dma-mapping: remove bogus test for pfn_valid from dma_map_resource

2021-10-01T13:54:45+00:00

dma_map_resource() uses pfn_valid() to ensure the range is not RAM.
However, pfn_valid() only checks for availability of the memory map for a
PFN but it does not ensure that the PFN is actually backed by RAM.

As dma_map_resource() is the only method in DMA mapping APIs that has this
check, simply drop the pfn_valid() test from dma_map_resource().

Link: https://lore.kernel.org/all/20210824173741.GC623@arm.com/
Signed-off-by: Mike Rapoport 
Reviewed-by: Christoph Hellwig 
Acked-by: David Hildenbrand 
Link: https://lore.kernel.org/r/20210930013039.11260-2-rppt@kernel.org
Signed-off-by: Will Deacon