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. On
ARM64 with SPARSEMEM (128MB section granularity), MMIO addresses that
share a section with RAM will falsely trigger the WARN_ON_ONCE and cause
dma_map_resource() to return DMA_MAPPING_ERROR.

This causes a WARNING on Raspberry Pi 4 during spi_bcm2835 probe because
the SPI FIFO register (0xfe204004) falls in the same sparsemem section
as the end of RAM (0xf8000000-0xfbffffff), both in section 31
(0xf8000000-0xffffffff).

Move the sanity check from dma_map_resource() into debug_dma_map_phys()
and replace the unreliable pfn_valid() with pfn_valid() &&
!PageReserved(), which correctly identifies actual usable RAM without
false positives for MMIO regions that happen to have struct pages.

Since dma_map_resource() is dma_map_phys(DMA_ATTR_MMIO), the check
applies equally to both APIs. Any non-reserved page represents kernel
memory to a sufficient degree that using DMA_ATTR_MMIO on it is almost
certainly wrong and risks breaking coherency on non-coherent platforms.
ZONE_DEVICE pages used for PCI P2P DMA (MEMORY_DEVICE_PCI_P2PDMA) have
PageReserved set, so they will not trigger a false positive.

The check no longer blocks the mapping and uses err_printk() to
integrate with dma-debug filtering.

Fixes: f7326196a781 ("dma-mapping: export new dma_*map_phys() interface")
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Jianpeng Chang <jianpeng.chang.cn@windriver.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260513072209.1486986-1-jianpeng.chang.cn@windriver.com

Calculate the correct physical address of the last byte of memory. Since
max_pfn is in fact "the PFN of the first page after the highest system RAM
in physical address space", the highest address that might be used for a
DMA buffer is one byte below max_pfn << PAGE_SHIFT.

This fix is unlikely to make any difference in practice. It's just that the
current formula is slightly confusing.

Signed-off-by: Petr Tesarik <ptesarik@suse.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260410113506.262579-1-ptesarik@suse.com

Pull memblock updates from Mike Rapoport:

 - improve debuggability of reserve_mem kernel parameter handling with
   print outs in case of a failure and debugfs info showing what was
   actually reserved

 - Make memblock_free_late() and free_reserved_area() use the same core
   logic for freeing the memory to buddy and ensure it takes care of
   updating memblock arrays when ARCH_KEEP_MEMBLOCK is enabled.

* tag 'memblock-v7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock:
  x86/alternative: delay freeing of smp_locks section
  memblock: warn when freeing reserved memory before memory map is initialized
  memblock, treewide: make memblock_free() handle late freeing
  memblock: make free_reserved_area() update memblock if ARCH_KEEP_MEMBLOCK=y
  memblock: extract page freeing from free_reserved_area() into a helper
  memblock: make free_reserved_area() more robust
  mm: move free_reserved_area() to mm/memblock.c
  powerpc: opal-core: pair alloc_pages_exact() with free_pages_exact()
  powerpc: fadump: pair alloc_pages_exact() with free_pages_exact()
  memblock: reserve_mem: fix end caclulation in reserve_mem_release_by_name()
  memblock: move reserve_bootmem_range() to memblock.c and make it static
  memblock: Add reserve_mem debugfs info
  memblock: Print out errors on reserve_mem parser

Pull dma-mapping updates from Marek Szyprowski:

 - added support for batched cache sync, what improves performance of
   dma_map/unmap_sg() operations on ARM64 architecture (Barry Song)

 - introduced DMA_ATTR_CC_SHARED attribute for explicitly shared memory
   used in confidential computing (Jiri Pirko)

 - refactored spaghetti-like code in drivers/of/of_reserved_mem.c and
   its clients (Marek Szyprowski, shared branch with device-tree updates
   to avoid merge conflicts)

 - prepared Contiguous Memory Allocator related code for making dma-buf
   drivers modularized (Maxime Ripard)

 - added support for benchmarking dma_map_sg() calls to tools/dma
   utility (Qinxin Xia)

* tag 'dma-mapping-7.1-2026-04-16' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux: (24 commits)
  dma-buf: heaps: system: document system_cc_shared heap
  dma-buf: heaps: system: add system_cc_shared heap for explicitly shared memory
  dma-mapping: introduce DMA_ATTR_CC_SHARED for shared memory
  mm: cma: Export cma_alloc(), cma_release() and cma_get_name()
  dma: contiguous: Export dev_get_cma_area()
  dma: contiguous: Make dma_contiguous_default_area static
  dma: contiguous: Make dev_get_cma_area() a proper function
  dma: contiguous: Turn heap registration logic around
  of: reserved_mem: rework fdt_init_reserved_mem_node()
  of: reserved_mem: clarify fdt_scan_reserved_mem*() functions
  of: reserved_mem: rearrange code a bit
  of: reserved_mem: replace CMA quirks by generic methods
  of: reserved_mem: switch to ops based OF_DECLARE()
  of: reserved_mem: use -ENODEV instead of -ENOENT
  of: reserved_mem: remove fdt node from the structure
  dma-mapping: fix false kernel-doc comment marker
  dma-mapping: Support batch mode for dma_direct_{map,unmap}_sg
  dma-mapping: Separate DMA sync issuing and completion waiting
  arm64: Provide dcache_inval_poc_nosync helper
  arm64: Provide dcache_clean_poc_nosync helper
  ...

Current CC designs don't place a vIOMMU in front of untrusted devices.
Instead, the DMA API forces all untrusted device DMA through swiotlb
bounce buffers (is_swiotlb_force_bounce()) which copies data into
shared memory on behalf of the device.

When a caller has already arranged for the memory to be shared
via set_memory_decrypted(), the DMA API needs to know so it can map
directly using the unencrypted physical address rather than bounce
buffering. Following the pattern of DMA_ATTR_MMIO, add
DMA_ATTR_CC_SHARED for this purpose. Like the MMIO case, only the
caller knows what kind of memory it has and must inform the DMA API
for it to work correctly.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260325192352.437608-2-jiri@resnulli.us

It shouldn't be responsibility of memblock users to detect if they free
memory allocated from memblock late and should use memblock_free_late().

Make memblock_free() and memblock_phys_free() take care of late memory
freeing and drop memblock_free_late().

Link: https://patch.msgid.link/20260323074836.3653702-9-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>

The CMA dma-buf heap uses the dev_get_cma_area() function to retrieve
the default contiguous area.

Now that this function is no longer inlined, and since we want to turn
the CMA heap into a module, let's export it.

Signed-off-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260331-dma-buf-heaps-as-modules-v4-4-e18fda504419@kernel.org

Now that dev_get_cma_area() is no longer inline, we don't have any user
of dma_contiguous_default_area() outside of contiguous.c so we can make
it static.

Signed-off-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260331-dma-buf-heaps-as-modules-v4-3-e18fda504419@kernel.org

As we try to enable dma-buf heaps, and the CMA one in particular, to
compile as modules, we need to export dev_get_cma_area(). It's currently
implemented as an inline function that returns either the content of
device->cma_area or dma_contiguous_default_area.

Thus, it means we need to export dma_contiguous_default_area, which
isn't really something we want any module to have access to.

Instead, let's make dev_get_cma_area() a proper function we will be able
to export so we can avoid exporting dma_contiguous_default_area.

Signed-off-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260331-dma-buf-heaps-as-modules-v4-2-e18fda504419@kernel.org