- move the USB special case that bounced DMA through a device
bar into the USB code instead of handling it in the common
DMA code (Laurentiu Tudor and Fredrik Noring)
- don't dip into the global CMA pool for single page allocations
(Nicolin Chen)
- fix a crash when allocating memory for the atomic pool failed
during boot (Florian Fainelli)
- move support for MIPS-style uncached segments to the common
code and use that for MIPS and nios2 (me)
- make support for DMA_ATTR_NON_CONSISTENT and
DMA_ATTR_NO_KERNEL_MAPPING generic (me)
- convert nds32 to the generic remapping allocator (me)
-----BEGIN PGP SIGNATURE-----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=01Fr
-----END PGP SIGNATURE-----
Merge tag 'dma-mapping-5.3' of git://git.infradead.org/users/hch/dma-mapping
Pull dma-mapping updates from Christoph Hellwig:
- move the USB special case that bounced DMA through a device bar into
the USB code instead of handling it in the common DMA code (Laurentiu
Tudor and Fredrik Noring)
- don't dip into the global CMA pool for single page allocations
(Nicolin Chen)
- fix a crash when allocating memory for the atomic pool failed during
boot (Florian Fainelli)
- move support for MIPS-style uncached segments to the common code and
use that for MIPS and nios2 (me)
- make support for DMA_ATTR_NON_CONSISTENT and
DMA_ATTR_NO_KERNEL_MAPPING generic (me)
- convert nds32 to the generic remapping allocator (me)
* tag 'dma-mapping-5.3' of git://git.infradead.org/users/hch/dma-mapping: (29 commits)
dma-mapping: mark dma_alloc_need_uncached as __always_inline
MIPS: only select ARCH_HAS_UNCACHED_SEGMENT for non-coherent platforms
usb: host: Fix excessive alignment restriction for local memory allocations
lib/genalloc.c: Add algorithm, align and zeroed family of DMA allocators
nios2: use the generic uncached segment support in dma-direct
nds32: use the generic remapping allocator for coherent DMA allocations
arc: use the generic remapping allocator for coherent DMA allocations
dma-direct: handle DMA_ATTR_NO_KERNEL_MAPPING in common code
dma-direct: handle DMA_ATTR_NON_CONSISTENT in common code
dma-mapping: add a dma_alloc_need_uncached helper
openrisc: remove the partial DMA_ATTR_NON_CONSISTENT support
arc: remove the partial DMA_ATTR_NON_CONSISTENT support
arm-nommu: remove the partial DMA_ATTR_NON_CONSISTENT support
ARM: dma-mapping: allow larger DMA mask than supported
dma-mapping: truncate dma masks to what dma_addr_t can hold
iommu/dma: Apply dma_{alloc,free}_contiguous functions
dma-remap: Avoid de-referencing NULL atomic_pool
MIPS: use the generic uncached segment support in dma-direct
dma-direct: provide generic support for uncached kernel segments
au1100fb: fix DMA API abuse
...
Replace the code that sets up uncached PTEs with the generic vmap based
remapping code. It also provides an atomic pool for allocations from
non-blocking context, which we not properly supported by the existing
arc code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Evgeniy Paltsev <paltsev@synopsys.com>
Tested-by: Evgeniy Paltsev <paltsev@synopsys.com>
The arc DMA code supports DMA_ATTR_NON_CONSISTENT allocations, but does
not provide a cache_sync operation. This means any user of it will
never be able to actually transfer cache ownership and thus cause
coherency bugs.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Evgeniy Paltsev <paltsev@synopsys.com>
Tested-by: Evgeniy Paltsev <paltsev@synopsys.com>
Based on 2 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 4122 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If we want to map memory from the DMA allocator to userspace it must be
zeroed at allocation time to prevent stale data leaks. We already do
this on most common architectures, but some architectures don't do this
yet, fix them up, either by passing GFP_ZERO when we use the normal page
allocator or doing a manual memset otherwise.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k]
Acked-by: Sam Ravnborg <sam@ravnborg.org> [sparc]
The only functional differences (modulo a few missing fixes in the arch
code) is that architectures without coherent caches need a hook to
convert a virtual or dma address into a pfn, given that we don't have
the kernel linear mapping available for the otherwise easy virt_to_page
call. As a side effect we can support mmap of the per-device coherent
area even on architectures not providing the callback, and we make
previous dangerous default methods dma_common_mmap actually save for
non-coherent architectures by rejecting it without the right helper.
In addition to that we need a hook so that some architectures can
override the protection bits when mmaping a dma coherent allocations.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Paul Burton <paul.burton@mips.com> # MIPS parts
All the cache maintainance is already stubbed out when not enabled,
but merging the two allows us to nicely handle the case where
cache maintainance is required for some devices, but not others.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Paul Burton <paul.burton@mips.com> # MIPS parts
__GFP_HIGHMEM flag is cleared by upper layer functions
(in include/linux/dma-mapping.h) so we'll never get a
__GFP_HIGHMEM flag in arch_dma_alloc gfp argument.
That's why alloc_pages will never return highmem page
here.
Get rid of highmem pages handling and cleanup arch_dma_alloc
and arch_dma_free functions.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
So far the IOC treatment was global on ARC, being turned on (or off)
for all devices in the system. With this patch, this can now be done
per device using the "dma-coherent" DT property; IOW with this patch
we can use both HW-coherent and regular DMA peripherals simultaneously.
The changes involved are too many so enlisting the summary below:
1. common code calls ARC arch_setup_dma_ops() per device.
2. For coherent dma (IOC) it plugs in generic @dma_direct_ops which
doesn't need any arch specific backend: No need for any explicit
cache flushes or MMU mappings to provide for uncached access
- dma_(map|sync)_single* return early as corresponding dma ops callbacks
are NULL in generic code.
So arch_sync_dma_*() -> dma_cache_*() need not handle the coherent
dma case, hence drop ARC __dma_cache_*_ioc() which were no-op anyways
3. For noncoherent dma (non IOC) generic @dma_noncoherent_ops is used
which in turns calls ARC specific routines
- arch_dma_alloc() no longer checks for @ioc_enable since this is
called only for !IOC case.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
[vgupta: rewrote changelog]
ARC backend for dma_sync_single_for_(device|cpu) was broken as it was
not honoring the @dir argument and simply forcing it based on the call:
- arc_dma_sync_single_for_device(dir) assumed DMA_TO_DEVICE (cache wback)
- arc_dma_sync_single_for_cpu(dir) assumed DMA_FROM_DEVICE (cache inv)
This is not true given the DMA API programming model and has been
discussed here [1] in some detail.
Interestingly while the deficiency has been there forever, it only started
showing up after 4.17 dma common ops rework, commit a8eb92d02d
("arc: fix arc_dma_{map,unmap}_page") which wired up these calls under the
more commonly used dma_map_page API triggering the issue.
[1]: https://lkml.org/lkml/2018/5/18/979
Fixes: commit a8eb92d02d ("arc: fix arc_dma_{map,unmap}_page")
Cc: stable@kernel.org # v4.17+
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
[vgupta: reworked changelog]
Switch to the generic noncoherent direct mapping implementation.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Alexey Brodkin <abrodkin@synopsys.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
These functions should perform the same cache synchronoization as calling
arc_dma_sync_single_for_{cpu,device} in addition to doing any required
address translation or mapping [1]. Ensure they actually do that by calling
arc_dma_sync_single_for_{cpu,device} instead of passing the dir argument
along to _dma_cache_sync.
The now unused _dma_cache_sync function is removed as well.
[1] in fact various drivers rely on that by passing DMA_ATTR_SKIP_CPU_SYNC
to the map/unmap routines and doing the cache synchronization manually.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Alexey Brodkin <abrodkin@synopsys.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
These functions should perform the same functionality as calling
arc_dma_sync_single_for_{cpu,device} on each S/G list element. Ensure
they actually do that by calling arc_dma_sync_single_for_{cpu,device}.
Otherwise we could be passing a different dir argument.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Alexey Brodkin <abrodkin@synopsys.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Remove the indirection through _dma_cache_sync. Also move the functions
up a bit in the source file as we'll need them in more places soon.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Alexey Brodkin <abrodkin@synopsys.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
We always use the stub definitions, so remove the unused other code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
- PAE40 related updates
- SLC errata for region ops
- intc line masking by default
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1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=mOLm
-----END PGP SIGNATURE-----
Merge tag 'arc-4.13-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc
Pull ARC fixes from Vineet Gupta:
- PAE40 related updates
- SLC errata for region ops
- intc line masking by default
* tag 'arc-4.13-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
arc: Mask individual IRQ lines during core INTC init
ARCv2: PAE40: set MSB even if !CONFIG_ARC_HAS_PAE40 but PAE exists in SoC
ARCv2: PAE40: Explicitly set MSB counterpart of SLC region ops addresses
ARC: dma: implement dma_unmap_page and sg variant
ARCv2: SLC: Make sure busy bit is set properly for region ops
ARC: [plat-sim] Include this platform unconditionally
ARC: [plat-axs10x]: prepare dts files for enabling PAE40 on axs103
ARC: defconfig: Cleanup from old Kconfig options
Christoph noticed [1] that default DMA pool in current form overload
the DMA coherent infrastructure. In reply, Robin suggested [2] to
split the per-device vs. global pool interfaces, so allocation/release
from default DMA pool is driven by dma ops implementation.
This patch implements Robin's idea and provide interface to
allocate/release/mmap the default (aka global) DMA pool.
To make it clear that existing *_from_coherent routines work on
per-device pool rename them to *_from_dev_coherent.
[1] https://lkml.org/lkml/2017/7/7/370
[2] https://lkml.org/lkml/2017/7/7/431
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Suggested-by: Robin Murphy <robin.murphy@arm.com>
Tested-by: Andras Szemzo <sza@esh.hu>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Patch series "Add support for DMA writable pages being writable by the
network stack", v3.
The first 19 patches in the set add support for the DMA attribute
DMA_ATTR_SKIP_CPU_SYNC on multiple platforms/architectures. This is
needed so that we can flag the calls to dma_map/unmap_page so that we do
not invalidate cache lines that do not currently belong to the device.
Instead we have to take care of this in the driver via a call to
sync_single_range_for_cpu prior to freeing the Rx page.
Patch 20 adds support for dma_map_page_attrs and dma_unmap_page_attrs so
that we can unmap and map a page using the DMA_ATTR_SKIP_CPU_SYNC
attribute.
Patch 21 adds support for freeing a page that has multiple references
being held by a single caller. This way we can free page fragments that
were allocated by a given driver.
The last 2 patches use these updates in the igb driver, and lay the
groundwork to allow for us to reimplement the use of build_skb.
This patch (of 23):
This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to
avoid invoking cache line invalidation if the driver will just handle it
later via a sync_for_cpu or sync_for_device call.
Link: http://lkml.kernel.org/r/20161110113419.76501.38491.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We used to use generic implementation of dma_map_ops.mmap which is
dma_common_mmap() but that only worked for simpler cached mappings when
vaddr = paddr.
If a driver requests uncached DMA buffer kernel maps it to virtual
address so that MMU gets involved and page uncached status takes into
account. In that case usage of dma_common_mmap() lead to mapping of
vaddr to vaddr for user-space which is obviously wrong. For more detals
please refer to verbose explanation here [1].
So here we implement our own version of mmap() which always deals
with dma_addr and maps underlying memory to user-space properly
(note that DMA buffer mapped to user-space is always uncached
because there's no way to properly manage cache from user-space).
[1] https://lkml.org/lkml/2016/10/26/973
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: <stable@vger.kernel.org> #4.5+
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
if user disables IOC from debugger at startup (by clearing @ioc_enable),
@ioc_exists is cleared too. This means boot prints don't capture the
fact that IOC was present but disabled which could be misleading.
So invert how we use @ioc_enable and @ioc_exists and make it more
canonical. @ioc_exists represent whether hardware is present or not and
stays same whether enabled or not. @ioc_enable is still user driven,
but will be auto-disabled if IOC hardware is not present, i.e. if
@ioc_exist=0. This is opposite to what we were doing before, but much
clearer.
This means @ioc_enable is now the "exported" toggle in rest of code such
as dma mapping API.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
The dma-mapping core and the implementations do not change the DMA
attributes passed by pointer. Thus the pointer can point to const data.
However the attributes do not have to be a bitfield. Instead unsigned
long will do fine:
1. This is just simpler. Both in terms of reading the code and setting
attributes. Instead of initializing local attributes on the stack
and passing pointer to it to dma_set_attr(), just set the bits.
2. It brings safeness and checking for const correctness because the
attributes are passed by value.
Semantic patches for this change (at least most of them):
virtual patch
virtual context
@r@
identifier f, attrs;
@@
f(...,
- struct dma_attrs *attrs
+ unsigned long attrs
, ...)
{
...
}
@@
identifier r.f;
@@
f(...,
- NULL
+ 0
)
and
// Options: --all-includes
virtual patch
virtual context
@r@
identifier f, attrs;
type t;
@@
t f(..., struct dma_attrs *attrs);
@@
identifier r.f;
@@
f(...,
- NULL
+ 0
)
Link: http://lkml.kernel.org/r/1468399300-5399-2-git-send-email-k.kozlowski@samsung.com
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no>
Acked-by: Mark Salter <msalter@redhat.com> [c6x]
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> [cris]
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> [drm]
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Acked-by: Joerg Roedel <jroedel@suse.de> [iommu]
Acked-by: Fabien Dessenne <fabien.dessenne@st.com> [bdisp]
Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com> [vb2-core]
Acked-by: David Vrabel <david.vrabel@citrix.com> [xen]
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> [xen swiotlb]
Acked-by: Joerg Roedel <jroedel@suse.de> [iommu]
Acked-by: Richard Kuo <rkuo@codeaurora.org> [hexagon]
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k]
Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> [s390]
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no> [avr32]
Acked-by: Vineet Gupta <vgupta@synopsys.com> [arc]
Acked-by: Robin Murphy <robin.murphy@arm.com> [arm64 and dma-iommu]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
page should be calculated using physical address.
If platform uses non-trivial dma-to-phys memory translation,
dma_handle should be converted to physicval address before
calculation of page.
Failing to do so results in struct page * pointing to
wrong or non-existent memory.
Fixes: f2e3d55397 ("ARC: dma: reintroduce platform specific dma<->phys")
Cc: stable@vger.kernel.org #4.6+
Signed-off-by: Vladimir Kondratiev <vladimir.kondratiev@intel.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Previously a non-coherent page (hardware IOC or simply driver needs)
could be handled by cpu with paddr alone (kvaddr used to be needed for
coherent mappings to enforce uncached semantics via a MMU mapping).
Now however such a page might still require a V-P mapping if it was in
physical address space > 32bits due to PAE40, which the CPU can't access
directly with a paddr
So decouple decision of kvaddr allocation from type of alloc request
(coh/non-coh)
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
vs. the ones which reutne void *, so that we can handle pages > 4GB
in subsequent patches
Also plug a potential page leak in case ioremap fails
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
In case of ARCv2 CPU there're could be following configurations
that affect cache handling for data exchanged with peripherals
via DMA:
[1] Only L1 cache exists
[2] Both L1 and L2 exist, but no IO coherency unit
[3] L1, L2 caches and IO coherency unit exist
Current implementation takes care of [1] and [2].
Moreover support of [2] is implemented with run-time check
for SLC existence which is not super optimal.
This patch introduces support of [3] and rework of DMA ops
usage. Instead of doing run-time check every time a particular
DMA op is executed we'll have 3 different implementations of
DMA ops and select appropriate one during init.
As for IOC support for it we need:
[a] Implement empty DMA ops because IOC takes care of cache
coherency with DMAed data
[b] Route dma_alloc_coherent() via dma_alloc_noncoherent()
This is required to make IOC work in first place and also
serves as optimization as LD/ST to coherent buffers can be
srviced from caches w/o going all the way to memory
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
[vgupta:
-Added some comments about IOC gains
-Marked dma ops as static,
-Massaged changelog a bit]
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
alloc_pages_exact() get gfp flags and handle zero'ing already
And while it, fix the case where ioremap fails: return rightaway.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
L2 cache on ARCHS processors is called SLC (System Level Cache)
For working DMA (in absence of hardware assisted IO Coherency) we need
to manage SLC explicitly when buffers transition between cpu and
controllers.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Linus Torvalds