Linaro-mm-sig

linaro-mm-sig@lists.linaro.org

10 participants
2527 discussions

[PATCH 1/3] [RFC] Kernel Virtual Memory allocation issue in dma-mapping framework

by Abhinav Kochhar

With this add a new attribute that can be passsed to dma-mapping IOMMU apis to differentiate between kernel and user allcoations. diff --git a/include/linux/dma-attrs.h b/include/linux/dma-attrs.h index 547ab56..861df09 100644 --- a/include/linux/dma-attrs.h +++ b/include/linux/dma-attrs.h @@ -15,6 +15,7 @@ enum dma_attr { DMA_ATTR_WEAK_ORDERING, DMA_ATTR_WRITE_COMBINE, DMA_ATTR_NON_CONSISTENT, + DMA_ATTR_USER_SPACE, DMA_ATTR_MAX, };

12 years, 7 months

[PATCH 0/3] [RFC] Kernel Virtual Memory allocation issue in dma-mapping framework

by Abhinav Kochhar

Hello, This is a request for comments on dma-mapping patches for ARM. I did some additions for issue related to kernel virtual memory allocations in the iommu ops defined in dma-mapping framework. The patches are based on: git://git.linaro.org/people/mszyprowski/linux-dma-mapping.git3.4-rc3-arm-dm… The code has been tested on Samsung Exynos5 SMDK5250. These patches do the following: 1. Define a new dma attribute to identify user space allocation. 2. Add new wrapper functions to pass the dma attribute defined in (1) above, as in the current framework there is no way to pass the new attribute which can be used to differentiate between kernel and user allocations. 3. Extend the existing arm_dma_ops for iommu enabled devices to differentiate between kernel and user space allocations. Patch summary: [PATCH 1/3]: Common: add DMA_ATTR_USER_SPACE to dma-attr. This can be passed to arm_dma_ops to identify the type of allocation which can be either from kernel or from user. [PATCH 2/3]: ARM: add "struct page_infodma" to hold information for allocated pages. This can be attached to any of the devices which is making use of dma-mapping APIs. Any interested device should allocate this structure and store all the relevant information about the allocated pages to be able to do a look up for all future references. ARM: add dma_alloc_writecombine_user() function to pass DMA_ATTR_USER_SPACE attribute ARM: add dma_free_writecombine_user() function to pass DMA_ATTR_USER_SPACE attribute ARM: add dma_mmap_writecombine_user() function to pass DMA_ATTR_USER_SPACE attribute [PATCH 3/3]: ARM: add check for allocation type in __dma_alloc_remap() function ARM: add check for allocation type in arm_iommu_alloc_attrs() function ARM: add check for allocation type in arm_iommu_mmap_attrs() function ARM: re-used dma_addr as a flag to check for memory allocation type. It was an unused argument and the prototype does not pass dma-attrs, so used this as a means to pass the flag. ARM: add check for allocation type in arm_iommu_free_attrs() function arch/arm/include/asm/dma-mapping.h | 31 +++++++ arch/arm/mm/dma-mapping.c | 168 ++++++++++++++++++++++++++---------- include/linux/dma-attrs.h | 1 + 3 files changed, 155 insertions(+), 45 deletions(-)

12 years, 7 months

[PATCHv24 00/16] Contiguous Memory Allocator

by Marek Szyprowski

Hi, This is (yet another) update of CMA patches. I've rebased them onto recent v3.4-rc1 kernel tree and integrated some minor bugfixes. The first issue has been pointed by Sandeep Patil - alloc_contig_range reclaimed two times too many pages, second issue (possible mismatch between pageblock size and MAX_ORDER pages) has been recently spotted by Michal Nazarewicz. These patches are also available on my git repository: git://git.linaro.org/people/mszyprowski/linux-dma-mapping.git 3.4-rc1-cma-v24 Best regards Marek Szyprowski Samsung Poland R&D Center Links to previous versions of the patchset: v23: <http://www.spinics.net/lists/linux-media/msg44547.html> v22: <http://www.spinics.net/lists/linux-media/msg44370.html> v21: <http://www.spinics.net/lists/linux-media/msg44155.html> v20: <http://www.spinics.net/lists/linux-mm/msg29145.html> v19: <http://www.spinics.net/lists/linux-mm/msg29145.html> v18: <http://www.spinics.net/lists/linux-mm/msg28125.html> v17: <http://www.spinics.net/lists/arm-kernel/msg148499.html> v16: <http://www.spinics.net/lists/linux-mm/msg25066.html> v15: <http://www.spinics.net/lists/linux-mm/msg23365.html> v14: <http://www.spinics.net/lists/linux-media/msg36536.html> v13: (internal, intentionally not released) v12: <http://www.spinics.net/lists/linux-media/msg35674.html> v11: <http://www.spinics.net/lists/linux-mm/msg21868.html> v10: <http://www.spinics.net/lists/linux-mm/msg20761.html> v9: <http://article.gmane.org/gmane.linux.kernel.mm/60787> v8: <http://article.gmane.org/gmane.linux.kernel.mm/56855> v7: <http://article.gmane.org/gmane.linux.kernel.mm/55626> v6: <http://article.gmane.org/gmane.linux.kernel.mm/55626> v5: (intentionally left out as CMA v5 was identical to CMA v4) v4: <http://article.gmane.org/gmane.linux.kernel.mm/52010> v3: <http://article.gmane.org/gmane.linux.kernel.mm/51573> v2: <http://article.gmane.org/gmane.linux.kernel.mm/50986> v1: <http://article.gmane.org/gmane.linux.kernel.mm/50669> Changelog: v24: 1. fixed handling of diffrent sizes of pageblock and MAX_ORDER size pages 2. fixed number of the reclaimed pages before performing the allocation (thanks to Sandeep Patil for pointing this issue) 3. rebased onto Linux v3.4-rc1 v23: 1. fixed bug spotted by Aaro Koskinen (incorrect check inside VM_BUG_ON) 2. rebased onto next-20120222 tree from git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git v22: 1. Fixed compilation break caused by missing fixup patch in v21 2. Fixed typos in the comments 3. Removed superfluous #include entries v21: 1. Fixed incorrect check which broke memory compaction code 2. Fixed hacky and racy min_free_kbytes handling 3. Added serialization patch to watermark calculation 4. Fixed typos here and there in the comments v20 and earlier - see previous patchsets. Patches in this patchset: Marek Szyprowski (6): mm: extract reclaim code from __alloc_pages_direct_reclaim() mm: trigger page reclaim in alloc_contig_range() to stabilise watermarks drivers: add Contiguous Memory Allocator X86: integrate CMA with DMA-mapping subsystem ARM: integrate CMA with DMA-mapping subsystem ARM: Samsung: use CMA for 2 memory banks for s5p-mfc device Mel Gorman (1): mm: Serialize access to min_free_kbytes Michal Nazarewicz (9): mm: page_alloc: remove trailing whitespace mm: compaction: introduce isolate_migratepages_range() mm: compaction: introduce map_pages() mm: compaction: introduce isolate_freepages_range() mm: compaction: export some of the functions mm: page_alloc: introduce alloc_contig_range() mm: page_alloc: change fallbacks array handling mm: mmzone: MIGRATE_CMA migration type added mm: page_isolation: MIGRATE_CMA isolation functions added Documentation/kernel-parameters.txt | 9 + arch/Kconfig | 3 + arch/arm/Kconfig | 2 + arch/arm/include/asm/dma-contiguous.h | 15 ++ arch/arm/include/asm/mach/map.h | 1 + arch/arm/kernel/setup.c | 9 +- arch/arm/mm/dma-mapping.c | 370 ++++++++++++++++++++++++------ arch/arm/mm/init.c | 23 ++- arch/arm/mm/mm.h | 3 + arch/arm/mm/mmu.c | 31 ++- arch/arm/plat-s5p/dev-mfc.c | 51 +---- arch/x86/Kconfig | 1 + arch/x86/include/asm/dma-contiguous.h | 13 + arch/x86/include/asm/dma-mapping.h | 4 + arch/x86/kernel/pci-dma.c | 18 ++- arch/x86/kernel/pci-nommu.c | 8 +- arch/x86/kernel/setup.c | 2 + drivers/base/Kconfig | 89 +++++++ drivers/base/Makefile | 1 + drivers/base/dma-contiguous.c | 401 +++++++++++++++++++++++++++++++ include/asm-generic/dma-contiguous.h | 28 +++ include/linux/device.h | 4 + include/linux/dma-contiguous.h | 110 +++++++++ include/linux/gfp.h | 12 + include/linux/mmzone.h | 47 +++- include/linux/page-isolation.h | 18 +- mm/Kconfig | 2 +- mm/Makefile | 3 +- mm/compaction.c | 418 +++++++++++++++++++++------------ mm/internal.h | 33 +++ mm/memory-failure.c | 2 +- mm/memory_hotplug.c | 6 +- mm/page_alloc.c | 409 ++++++++++++++++++++++++++++---- mm/page_isolation.c | 15 +- mm/vmstat.c | 3 + 35 files changed, 1791 insertions(+), 373 deletions(-) create mode 100644 arch/arm/include/asm/dma-contiguous.h create mode 100644 arch/x86/include/asm/dma-contiguous.h create mode 100644 drivers/base/dma-contiguous.c create mode 100644 include/asm-generic/dma-contiguous.h create mode 100644 include/linux/dma-contiguous.h -- 1.7.1.569.g6f426

12 years, 7 months

[PATCHv5 00/13] Integration of videobuf2 with dmabuf

by Tomasz Stanislawski

Hello everyone, This patchset adds support for DMABUF [2] importing to V4L2 stack. The support for DMABUF exporting was moved to separate patchset due to dependency on patches for DMA mapping redesign by Marek Szyprowski [4]. v5: - removed change of importer/exporter behaviour - fixes vb2_dc_pages_to_sgt basing on Laurent's hints - changed pin/unpin words to lock/unlock in Doc v4: - rebased on mainline 3.4-rc2 - included missing importing support for s5p-fimc and s5p-tv - added patch for changing map/unmap for importers - fixes to Documentation part - coding style fixes - pairing {map/unmap}_dmabuf in vb2-core - fixing variable types and semantic of arguments in videobufb2-dma-contig.c v3: - rebased on mainline 3.4-rc1 - split 'code refactor' patch to multiple smaller patches - squashed fixes to Sumit's patches - patchset is no longer dependant on 'DMA mapping redesign' - separated path for handling IO and non-IO mappings - add documentation for DMABUF importing to V4L - removed all DMABUF exporter related code - removed usage of dma_get_pages extension v2: - extended VIDIOC_EXPBUF argument from integer memoffset to struct v4l2_exportbuffer - added patch that breaks DMABUF spec on (un)map_atachment callcacks but allows to work with existing implementation of DMABUF prime in DRM - all dma-contig code refactoring patches were squashed - bugfixes v1: List of changes since [1]. - support for DMA api extension dma_get_pages, the function is used to retrieve pages used to create DMA mapping. - small fixes/code cleanup to videobuf2 - added prepare and finish callbacks to vb2 allocators, it is used keep consistency between dma-cpu acess to the memory (by Marek Szyprowski) - support for exporting of DMABUF buffer in V4L2 and Videobuf2, originated from [3]. - support for dma-buf exporting in vb2-dma-contig allocator - support for DMABUF for s5p-tv and s5p-fimc (capture interface) drivers, originated from [3] - changed handling for userptr buffers (by Marek Szyprowski, Andrzej Pietrasiewicz) - let mmap method to use dma_mmap_writecombine call (by Marek Szyprowski) [1] http://thread.gmane.org/gmane.linux.drivers.video-input-infrastructure/4296… [2] https://lkml.org/lkml/2011/12/26/29 [3] http://thread.gmane.org/gmane.linux.drivers.video-input-infrastructure/3635… [4] http://thread.gmane.org/gmane.linux.kernel.cross-arch/12819 Andrzej Pietrasiewicz (1): v4l: vb2-dma-contig: add support for scatterlist in userptr mode Laurent Pinchart (2): v4l: vb2-dma-contig: Shorten vb2_dma_contig prefix to vb2_dc v4l: vb2-dma-contig: Reorder functions Marek Szyprowski (2): v4l: vb2: add prepare/finish callbacks to allocators v4l: vb2-dma-contig: add prepare/finish to dma-contig allocator Sumit Semwal (4): v4l: Add DMABUF as a memory type v4l: vb2: add support for shared buffer (dma_buf) v4l: vb: remove warnings about MEMORY_DMABUF v4l: vb2-dma-contig: add support for dma_buf importing Tomasz Stanislawski (4): Documentation: media: description of DMABUF importing in V4L2 v4l: vb2-dma-contig: Remove unneeded allocation context structure v4l: s5p-tv: mixer: support for dmabuf importing v4l: s5p-fimc: support for dmabuf importing Documentation/DocBook/media/v4l/compat.xml | 4 + Documentation/DocBook/media/v4l/io.xml | 179 +++++++ .../DocBook/media/v4l/vidioc-create-bufs.xml | 1 + Documentation/DocBook/media/v4l/vidioc-qbuf.xml | 15 + Documentation/DocBook/media/v4l/vidioc-reqbufs.xml | 47 +- drivers/media/video/Kconfig | 1 + drivers/media/video/s5p-fimc/fimc-capture.c | 2 +- drivers/media/video/s5p-tv/Kconfig | 1 + drivers/media/video/s5p-tv/mixer_video.c | 2 +- drivers/media/video/videobuf-core.c | 4 + drivers/media/video/videobuf2-core.c | 207 ++++++++- drivers/media/video/videobuf2-dma-contig.c | 529 +++++++++++++++++--- include/linux/videodev2.h | 7 + include/media/videobuf2-core.h | 34 ++ 14 files changed, 932 insertions(+), 101 deletions(-) -- 1.7.5.4

12 years, 7 months

Minutes from V4L2 update call

by Christian Robottom Reis

Hey there, We ran a call today on the topics of V4L2/dmabuf integration and the DMA mapping changes; I've included minutes and actions below. In summary: - We're not going to see the V4L2 patches in 3.4; they haven't had enough review or testing and Mauro is very busy this merge window. - We're going to put in effort to validate the work on Exynos4 and OMAP4 using test applications that Rob and Tomasz are maintaining. - Sumit's maintaining an up-to-date branch containing all the in-flight DRM/V4L2/dmabuf-dependent work that we can carry meanwhile: http://git.linaro.org/gitweb?p=people/sumitsemwal/linux-3.x.git;a=shortlog;… Laurent, I missed one thing that you mentioned in the call and it's included in an XXX: below; if you could note what it was it would be great. Please feel free to correct my possibly wild misunderstandings in the minutes and summary above. Thanks! Attendees are all on the To: line. Tomasz: At the moment, have PoC support for import/export dma-buf for V4L2 Modified patches by Sumit Supporting importer of dma-buf Exynos DRM and drm-prime Test application worked fine for V4L capture and DRM output Test application between two V4L devices Laurent has sent in review comments Tomasz: proposed extension to DMA Mapping -- dma_get_pages Currently difficult to change the camera address into list of pages DMA framework has the knowledge of this list and could do this Depends on dma_get_pages Needs to be merged first Test application posted to dri-devel with dependencies to run demo Many dependencies Topic: dmabuf importer from V4L2 For sharing with DRM do not need exporter Need some patches added to DRM prime prime for Exynos drm-prime ACTION: Tomasz to check with Inki Dae and David A. on status Will send request to Mauro? Doesn't think so, won't have enough time for testing RC is already open -- not enough time for that API details needs consideration Depends on how much time current project 2-3 weeks after the merge window closes 1 month to actually review Would like to see Exynos working Mauro has a Samsung V310/Exynos4 dev board Also wants to see tested with V4L driver virtual drivers also supporting dma-buf wants both importer and exporter? ACTION: Sumit to look into VV driver used for v4l2 testing needs importer and exporter Laurent has work that he can push forward in parallel API change ioctl addition that could be reviewed Rob: the demo had V4L importer and DRM exporter (?) There are some changes for prime changes Laurent: needs to implement importer/exporter camera piece With drm-prime-dmabuf patches drivers can be simplified Sumit: we have a new 3.3-WIP branch Rob could use that as a base and put DRM updates on it ACTION: Rob to pull in changes and update demonstration Rob: what camera does Mauro have? On the Samsung SDK, M5MOLS Mauro does have a Pandaboard with ov5650 camera but needs setting up and potential hardware mod ACTION: Mauro to take picture of setup for Sumit As a backup Rob could add a Tested-By for the changes Mauro essentially wants a test on With CPU access in dmabuf can use vmalloc Without dependency on dma mapping at all Without Russell's acceptance can't go forward with ARM-related pieces ACTION: Kiko to check with Nicolas on this piece, see if he can review or help Marek with the ARM-related pieces Tomasz could use the 3.3-WIP branch Sumit: rebasing not a good idea, but could pull in for-next Suggests Tomasz bases work on Linus' mainline Had problems with Tomasz' branch that is based on -next His branch includes Tomasz RFCv2 patches as well Laurent: agree with Sumit ACTION: Sumit to email Tomasz and CC: Inki Dae ACTION: send around latest drm-prime branch Tomasz: so no XXX: exporter support for V4L? Laurent: doesn't have time to update XXX at the moment Needs porting to videobuf2 Rob: Looks like Daniel V. has also replied to the V4L patches so it's going to be hard for 3.4 Mauro's lack of time makes 3.4 not possible anyway mmap support also likely to miss 3.4 EGLImage extension needs sorting out Can be carried in our WIP branch meanwhile Mauro: what are the test applications being used for dmabuf? Rob: using Panda with camera adapter board (omap-drm) Would like others to have similar setups Requires YUV sensor, but there are patches that support the RAW YUV conversion which allows other sensors to be used Mauro: but what software app are you using? Rob: has test code in github: https://github.com/robclark/omapdrmtest Tomasz: Have posted one test application on dri-devel (March 6th) http://www.spinics.net/lists/dri-devel/msg19634.html Second application posted to linux-media As a reply to RFCv1 dma-buf V4L2 patches (Jan 26th) http://www.mail-archive.com/linux-media@vger.kernel.org/msg42522.html Mauro: include both applications together with patches when posting Sumit: could ask Inki to provide similar exynos-drm test application in parallel to Rob's omap-drm; same interface will simplify testing Marek: device-to-device coordinate will be needed Will start next week ideally For a device-to-device operation, need this to avoid touching CPU cache Not sure about ARM stuff for 3.4; need review If they don't go in, will keep on dma-mapping-next Konrad's comments are addressed and Reviewed-bys added Take care, -- Christian Robottom Reis, Engineering VP Brazil (GMT-3) | [+55] 16 9112 6430 | [+1] 612 216 4935 Linaro.org: Open Source Software for ARM SoCs

12 years, 7 months

[PATCH] drm: pass dev to drm_vm_{open, close}_locked()

by Rob Clark

From: Rob Clark <rob(a)ti.com> Previously these functions would assume that vma->vm_file was the drm_file. Although if in some cases if the drm driver needs to use something else for the backing file (such as the tmpfs filp) then this assumption is no longer true. But vma->vm_private_data is still the GEM object. With this change, now the drm_device comes from the GEM object rather than the drm_file so the driver is more free to play with vma->vm_file. The scenario where this comes up is for mmap'ing of cached dmabuf's for non-coherent systems, where the driver needs to use fault handling and PTE shootdown to simulate coherency. We can't use the vma->vm_file of the dmabuf, which is using anon_inode's address_space. The most straightforward thing to do is to use the GEM object's obj->filp for vma->vm_file in all cases, for which we need this patch. Signed-off-by: Rob Clark <rob(a)ti.com> --- drivers/gpu/drm/drm_gem.c | 6 +++--- drivers/gpu/drm/drm_vm.c | 18 ++++++++---------- include/drm/drmP.h | 4 ++-- 3 files changed, 13 insertions(+), 15 deletions(-) diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c index 83114b5..475b300 100644 --- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -628,7 +628,7 @@ void drm_gem_vm_open(struct vm_area_struct *vma) drm_gem_object_reference(obj); mutex_lock(&obj->dev->struct_mutex); - drm_vm_open_locked(vma); + drm_vm_open_locked(obj->dev, vma); mutex_unlock(&obj->dev->struct_mutex); } EXPORT_SYMBOL(drm_gem_vm_open); @@ -639,7 +639,7 @@ void drm_gem_vm_close(struct vm_area_struct *vma) struct drm_device *dev = obj->dev; mutex_lock(&dev->struct_mutex); - drm_vm_close_locked(vma); + drm_vm_close_locked(obj->dev, vma); drm_gem_object_unreference(obj); mutex_unlock(&dev->struct_mutex); } @@ -712,7 +712,7 @@ int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma) */ drm_gem_object_reference(obj); - drm_vm_open_locked(vma); + drm_vm_open_locked(dev, vma); out_unlock: mutex_unlock(&dev->struct_mutex); diff --git a/drivers/gpu/drm/drm_vm.c b/drivers/gpu/drm/drm_vm.c index 1495618..961ee08 100644 --- a/drivers/gpu/drm/drm_vm.c +++ b/drivers/gpu/drm/drm_vm.c @@ -406,10 +406,9 @@ static const struct vm_operations_struct drm_vm_sg_ops = { * Create a new drm_vma_entry structure as the \p vma private data entry and * add it to drm_device::vmalist. */ -void drm_vm_open_locked(struct vm_area_struct *vma) +void drm_vm_open_locked(struct drm_device *dev, + struct vm_area_struct *vma) { - struct drm_file *priv = vma->vm_file->private_data; - struct drm_device *dev = priv->minor->dev; struct drm_vma_entry *vma_entry; DRM_DEBUG("0x%08lx,0x%08lx\n", @@ -430,14 +429,13 @@ static void drm_vm_open(struct vm_area_struct *vma) struct drm_device *dev = priv->minor->dev; mutex_lock(&dev->struct_mutex); - drm_vm_open_locked(vma); + drm_vm_open_locked(dev, vma); mutex_unlock(&dev->struct_mutex); } -void drm_vm_close_locked(struct vm_area_struct *vma) +void drm_vm_close_locked(struct drm_device *dev, + struct vm_area_struct *vma) { - struct drm_file *priv = vma->vm_file->private_data; - struct drm_device *dev = priv->minor->dev; struct drm_vma_entry *pt, *temp; DRM_DEBUG("0x%08lx,0x%08lx\n", @@ -467,7 +465,7 @@ static void drm_vm_close(struct vm_area_struct *vma) struct drm_device *dev = priv->minor->dev; mutex_lock(&dev->struct_mutex); - drm_vm_close_locked(vma); + drm_vm_close_locked(dev, vma); mutex_unlock(&dev->struct_mutex); } @@ -519,7 +517,7 @@ static int drm_mmap_dma(struct file *filp, struct vm_area_struct *vma) vma->vm_flags |= VM_RESERVED; /* Don't swap */ vma->vm_flags |= VM_DONTEXPAND; - drm_vm_open_locked(vma); + drm_vm_open_locked(dev, vma); return 0; } @@ -670,7 +668,7 @@ int drm_mmap_locked(struct file *filp, struct vm_area_struct *vma) vma->vm_flags |= VM_RESERVED; /* Don't swap */ vma->vm_flags |= VM_DONTEXPAND; - drm_vm_open_locked(vma); + drm_vm_open_locked(dev, vma); return 0; } diff --git a/include/drm/drmP.h b/include/drm/drmP.h index dd73104..213a85a 100644 --- a/include/drm/drmP.h +++ b/include/drm/drmP.h @@ -1309,8 +1309,8 @@ extern int drm_release(struct inode *inode, struct file *filp); /* Mapping support (drm_vm.h) */ extern int drm_mmap(struct file *filp, struct vm_area_struct *vma); extern int drm_mmap_locked(struct file *filp, struct vm_area_struct *vma); -extern void drm_vm_open_locked(struct vm_area_struct *vma); -extern void drm_vm_close_locked(struct vm_area_struct *vma); +extern void drm_vm_open_locked(struct drm_device *dev, struct vm_area_struct *vma); +extern void drm_vm_close_locked(struct drm_device *dev, struct vm_area_struct *vma); extern unsigned int drm_poll(struct file *filp, struct poll_table_struct *wait); /* Memory management support (drm_memory.h) */ -- 1.7.9.5

12 years, 7 months

Re: [Linaro-mm-sig] ION interfaces - support for IOMMU

by Hiroshi Doyu

Hi Nishanth, On Sun, 29 Apr 2012 21:56:26 +0200 Nishanth Peethambaran <nishanth.peethu(a)gmail.com> wrote: > Hi Rebecca, Doyu, > > I am sending this mail related to the mailchain seen in the link: > http://lists.linaro.org/pipermail/linaro-mm-sig/2012-January/001009.html > I am not sure where to post the query. If I am supposed to post in a > mail-list, let me know and > I shall post it there. I think that "linaro-mm-sig(a)lists.linaro.org" would be the best for further discussion, putting linaro-mm-sig on Cc:. > I am also trying to use ION for IOMMU and have some comments on ION in > general and specific to IOMMU usage. > 1. Isn't 2 heap types sufficient - physically contiguous and non-contiguous? > We could treat physical carveout and sytem_contig(kmalloc) as two > implementations of physcially contiguous type > and add the heaps with separate ids. Order of using them would be > as ION currently does - order of registration of heap. > IOMMU heap type also won't be needed as that is just a different > implementation of system heap (no kernel map at allocation > time). Please correct me if I am missing something. > > 2. The user space interface does not support exposing a dma_addr_t to > user space. We could add this using custom ioctl. > But, shouldn't this be a standard interface. For example, to > protect/hide the graphics core IP details, platfrom provider would > prefer to generate graphics core program from user space (license > requirements) and only pass the final buffer containing > the program to the driver. If an IOMMU is used, the dma/iommu > address mapping would be needed in user space to embed > few pointers in the graphics program. > > 3. With the current ION implementation, how do we keep user space > code/drivers independent of platform supporting IOMMU or not? > For example, CMA is supported by the platform but want to restrict > buffers allocated from CMA only if necessary (to avoid migration > overheads). How does a client decide whether to request for > physically contiguous buffers (CMA) ot IOMMU buffers (buddy allocator) > In one platform, the buffer could be shared with an IP with IOMMU > support (eg: camera and codec both supporting IOMMU) - CMA not needed. > In another platform the buffer may have to be shared with an IP > which works on physical address space. buffer has to be > shared with an IP which does not support IOMMU(to avoid migrations) > - we need to use physically contiguous heap(CMA). > I see dma buf sharing API has a callback to exporter at attachment > time so that exporter can pass of fail the sharing based on the > receiver. > Don't we need something similar and more? > > ION version referred: > commit 3fe24366a40147d7c776e1f291193fd3b61f217d > Author: Iliyan Malchev <malchev(a)google.com> > Date: Tue Aug 9 14:42:08 2011 -0700 > > - Nishanth Peethambaran

12 years, 7 months

[PATCHv5 00/13] Integration of videobuf2 with dmabuf

by Tomasz Stanislawski

12 years, 8 months

[PATCH] dma-buf: mmap support

by Daniel Vetter

Compared to Rob Clark's RFC I've ditched the prepare/finish hooks and corresponding ioctls on the dma_buf file. The major reason for that is that many people seem to be under the impression that this is also for synchronization with outstanding asynchronous processsing. I'm pretty massively opposed to this because: - It boils down reinventing a new rather general-purpose userspace synchronization interface. If we look at things like futexes, this is hard to get right. - Furthermore a lot of kernel code has to interact with this synchronization primitive. This smells a look like the dri1 hw_lock, a horror show I prefer not to reinvent. - Even more fun is that multiple different subsystems would interact here, so we have plenty of opportunities to create funny deadlock scenarios. I think synchronization is a wholesale different problem from data sharing and should be tackled as an orthogonal problem. Now we could demand that prepare/finish may only ensure cache coherency (as Rob intended), but that runs up into the next problem: We not only need mmap support to facilitate sw-only processing nodes in a pipeline (without jumping through hoops by importing the dma_buf into some sw-access only importer), which allows for a nicer ION->dma-buf upgrade path for existing Android userspace. We also need mmap support for existing importing subsystems to support existing userspace libraries. And a loot of these subsystems are expected to export coherent userspace mappings. So prepare/finish can only ever be optional and the exporter /needs/ to support coherent mappings. Given that mmap access is always somewhat fallback-y in nature I've decided to drop this optimization, instead of just making it optional. If we demonstrate a clear need for this, supported by benchmark results, we can always add it in again later as an optional extension. Other differences compared to Rob's RFC is the above mentioned support for mapping a dma-buf through facilities provided by the importer. Which results in mmap support no longer being optional. Note that this dma-buf mmap patch does _not_ support every possible insanity an existing subsystem could pull of with mmap: Because it does not allow to intercept pagefaults and shoot down ptes importing subsystems can't add some magic of their own at these points (e.g. to automatically synchronize with outstanding rendering or set up some special resources). I've done a cursory read through a few mmap implementions of various subsytems and I'm hopeful that we can avoid this (and the complexity it'd bring with it). Additonally I've extended the documentation a bit to explain the hows and whys of this mmap extension. In case we ever want to add support for explicitly cache maneged userspace mmap with a prepare/finish ioctl pair, we could specify that userspace needs to mmap a different part of the dma_buf, e.g. the range starting at dma_buf->size up to dma_buf->size*2. This works because the size of a dma_buf is invariant over it's lifetime. The exporter would obviously need to fall back to coherent mappings for both ranges if a legacy clients maps the coherent range and the architecture cannot suppor conflicting caching policies. Also, this would obviously be optional and userspace needs to be able to fall back to coherent mappings. v2: - Spelling fixes from Rob Clark. - Compile fix for !DMA_BUF from Rob Clark. - Extend commit message to explain how explicitly cache managed mmap support could be added later. - Extend the documentation with implementations notes for exporters that need to manually fake coherency. Cc: Rob Clark <rob.clark(a)linaro.org> Cc: Rebecca Schultz Zavin <rebecca(a)android.com> Signed-Off-by: Daniel Vetter <daniel.vetter(a)ffwll.ch> --- Documentation/dma-buf-sharing.txt | 98 ++++++++++++++++++++++++++++++++++--- drivers/base/dma-buf.c | 64 +++++++++++++++++++++++- include/linux/dma-buf.h | 16 ++++++ 3 files changed, 170 insertions(+), 8 deletions(-) diff --git a/Documentation/dma-buf-sharing.txt b/Documentation/dma-buf-sharing.txt index 3bbd5c5..5ff4d2b 100644 --- a/Documentation/dma-buf-sharing.txt +++ b/Documentation/dma-buf-sharing.txt @@ -29,13 +29,6 @@ The buffer-user in memory, mapped into its own address space, so it can access the same area of memory. -*IMPORTANT*: [see https://lkml.org/lkml/2011/12/20/211 for more details] -For this first version, A buffer shared using the dma_buf sharing API: -- *may* be exported to user space using "mmap" *ONLY* by exporter, outside of - this framework. -- with this new iteration of the dma-buf api cpu access from the kernel has been - enable, see below for the details. - dma-buf operations for device dma only -------------------------------------- @@ -313,6 +306,83 @@ Access to a dma_buf from the kernel context involves three steps: enum dma_data_direction dir); +Direct Userspace Access/mmap Support +------------------------------------ + +Being able to mmap an export dma-buf buffer object has 2 main use-cases: +- CPU fallback processing in a pipeline and +- supporting existing mmap interfaces in importers. + +1. CPU fallback processing in a pipeline + + In many processing pipelines it is sometimes required that the cpu can access + the data in a dma-buf (e.g. for thumbnail creation, snapshots, ...). To avoid + the need to handle this specially in userspace frameworks for buffer sharing + it's ideal if the dma_buf fd itself can be used to access the backing storage + from userspace using mmap. + + Furthermore Android's ION framework already supports this (and is otherwise + rather similar to dma-buf from a userspace consumer side with using fds as + handles, too). So it's beneficial to support this in a similar fashion on + dma-buf to have a good transition path for existing Android userspace. + + No special interfaces, userspace simply calls mmap on the dma-buf fd. + +2. Supporting existing mmap interfaces in exporters + + Similar to the motivation for kernel cpu access it is again important that + the userspace code of a given importing subsystem can use the same interfaces + with a imported dma-buf buffer object as with a native buffer object. This is + especially important for drm where the userspace part of contemporary OpenGL, + X, and other drivers is huge, and reworking them to use a different way to + mmap a buffer rather invasive. + + The assumption in the current dma-buf interfaces is that redirecting the + initial mmap is all that's needed. A survey of some of the existing + subsystems shows that no driver seems to do any nefarious thing like syncing + up with outstanding asynchronous processing on the device or allocating + special resources at fault time. So hopefully this is good enough, since + adding interfaces to intercept pagefaults and allow pte shootdowns would + increase the complexity quite a bit. + + Interface: + int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *, + unsigned long); + + If the importing subsystem simply provides a special-purpose mmap call to set + up a mapping in userspace, calling do_mmap with dma_buf->file will equally + achieve that for a dma-buf object. + +3. Implementation notes for exporters + + Because dma-buf buffers have invariant size over their lifetime, the dma-buf + core checks whether a vma is too large and rejects such mappings. The + exporter hence does not need to duplicate this check. + + Because existing importing subsystems might presume coherent mappings for + userspace, the exporter needs to set up a coherent mapping. If that's not + possible, it needs to fake coherency by manually shooting down ptes when + leaving the cpu domain and flushing caches at fault time. Note that all the + dma_buf files share the same anon inode, hence the exporter needs to replace + the dma_buf file stored in vma->vm_file with it's own if pte shootdown is + requred. This is because the kernel uses the underlying inode's address_space + for vma tracking (and hence pte tracking at shootdown time with + unmap_mapping_range). + + If the above shootdown dance turns out to be too expensive in certain + scenarios, we can extend dma-buf with a more explicit cache tracking scheme + for userspace mappings. But the current assumption is that using mmap is + always a slower path, so some inefficiencies should be acceptable. + + Exporters that shoot down mappings (for any reasons) shall not do any + synchronization at fault time with outstanding device operations. + Synchronization is an orthogonal issue to sharing the backing storage of a + buffer and hence should not be handled by dma-buf itself. This is explictly + mentioned here because many people seem to want something like this, but if + different exporters handle this differently, buffer sharing can fail in + interesting ways depending upong the exporter (if userspace starts depending + upon this implicit synchronization). + Miscellaneous notes ------------------- @@ -336,6 +406,20 @@ Miscellaneous notes the exporting driver to create a dmabuf fd must provide a way to let userspace control setting of O_CLOEXEC flag passed in to dma_buf_fd(). +- If an exporter needs to manually flush caches and hence needs to fake + coherency for mmap support, it needs to be able to zap all the ptes pointing + at the backing storage. Now linux mm needs a struct address_space associated + with the struct file stored in vma->vm_file to do that with the function + unmap_mapping_range. But the dma_buf framework only backs every dma_buf fd + with the anon_file struct file, i.e. all dma_bufs share the same file. + + Hence exporters need to setup their own file (and address_space) association + by setting vma->vm_file and adjusting vma->vm_pgoff in the dma_buf mmap + callback. In the specific case of a gem driver the exporter could use the + shmem file already provided by gem (and set vm_pgoff = 0). Exporters can then + zap ptes by unmapping the corresponding range of the struct address_space + associated with their own file. + References: [1] struct dma_buf_ops in include/linux/dma-buf.h [2] All interfaces mentioned above defined in include/linux/dma-buf.h diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c index 07cbbc6..8a573b9 100644 --- a/drivers/base/dma-buf.c +++ b/drivers/base/dma-buf.c @@ -44,8 +44,26 @@ static int dma_buf_release(struct inode *inode, struct file *file) return 0; } +static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma) +{ + struct dma_buf *dmabuf; + + if (!is_dma_buf_file(file)) + return -EINVAL; + + /* check for overflowing the buffer's size */ + if (vma->vm_pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) > + dmabuf->size >> PAGE_SHIFT) + return -EINVAL; + + dmabuf = file->private_data; + + return dmabuf->ops->mmap(dmabuf, vma); +} + static const struct file_operations dma_buf_fops = { .release = dma_buf_release, + .mmap = dma_buf_mmap_internal, }; /* @@ -82,7 +100,8 @@ struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops, || !ops->unmap_dma_buf || !ops->release || !ops->kmap_atomic - || !ops->kmap)) { + || !ops->kmap + || !ops->mmap)) { return ERR_PTR(-EINVAL); } @@ -406,3 +425,46 @@ void dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long page_num, dmabuf->ops->kunmap(dmabuf, page_num, vaddr); } EXPORT_SYMBOL_GPL(dma_buf_kunmap); + + +/** + * dma_buf_mmap - Setup up a userspace mmap with the given vma + * @dma_buf: [in] buffer that should back the vma + * @vma: [in] vma for the mmap + * @pgoff: [in] offset in pages where this mmap should start within the + * dma-buf buffer. + * + * This function adjusts the passed in vma so that it points at the file of the + * dma_buf operation. It alsog adjusts the starting pgoff and does bounds + * checking on the size of the vma. Then it calls the exporters mmap function to + * set up the mapping. + * + * Can return negative error values, returns 0 on success. + */ +int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, + unsigned long pgoff) +{ + if (WARN_ON(!dmabuf || !vma)) + return -EINVAL; + + /* check for offset overflow */ + if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) < pgoff) + return -EOVERFLOW; + + /* check for overflowing the buffer's size */ + if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) > + dmabuf->size >> PAGE_SHIFT) + return -EINVAL; + + /* readjust the vma */ + if (vma->vm_file) + fput(vma->vm_file); + + vma->vm_file = dmabuf->file; + get_file(vma->vm_file); + + vma->vm_pgoff = pgoff; + + return dmabuf->ops->mmap(dmabuf, vma); +} +EXPORT_SYMBOL_GPL(dma_buf_mmap); diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 3efbfc2..1f78d15 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -61,6 +61,10 @@ struct dma_buf_attachment; * This Callback must not sleep. * @kmap: maps a page from the buffer into kernel address space. * @kunmap: [optional] unmaps a page from the buffer. + * @mmap: used to expose the backing storage to userspace. Note that the + * mapping needs to be coherent - if the exporter doesn't directly + * support this, it needs to fake coherency by shooting down any ptes + * when transitioning away from the cpu domain. */ struct dma_buf_ops { int (*attach)(struct dma_buf *, struct device *, @@ -92,6 +96,8 @@ struct dma_buf_ops { void (*kunmap_atomic)(struct dma_buf *, unsigned long, void *); void *(*kmap)(struct dma_buf *, unsigned long); void (*kunmap)(struct dma_buf *, unsigned long, void *); + + int (*mmap)(struct dma_buf *, struct vm_area_struct *vma); }; /** @@ -167,6 +173,9 @@ void *dma_buf_kmap_atomic(struct dma_buf *, unsigned long); void dma_buf_kunmap_atomic(struct dma_buf *, unsigned long, void *); void *dma_buf_kmap(struct dma_buf *, unsigned long); void dma_buf_kunmap(struct dma_buf *, unsigned long, void *); + +int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *, + unsigned long); #else static inline struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, @@ -248,6 +257,13 @@ static inline void dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long pnum, void *vaddr) { } + +static inline int dma_buf_mmap(struct dma_buf *dmabuf, + struct vm_area_struct *vma, + unsigned long pgoff) +{ + return -ENODEV; +} #endif /* CONFIG_DMA_SHARED_BUFFER */ #endif /* __DMA_BUF_H__ */ -- 1.7.10

12 years, 8 months

[PATCH 0/4] ARM: replace custom consistent dma region with vmalloc

by Marek Szyprowski

Hi! Recent changes to ioremap and unification of vmalloc regions on ARM significantly reduces the possible size of the consistent dma region and limited allowed dma coherent/writecombine allocations. This experimental patch series replaces custom consistent dma regions usage in dma-mapping framework in favour of generic vmalloc areas created on demand for each coherent and writecombine allocations. This patch is based on vanilla v3.4-rc2 release. Best regards Marek Szyprowski Samsung Poland R&D Center Patch summary: Marek Szyprowski (4): mm: vmalloc: use const void * for caller argument mm: vmalloc: export find_vm_area() function mm: vmalloc: add VM_DMA flag to indicate areas used by dma-mapping framework ARM: remove consistent dma region and use common vmalloc range for dma allocations arch/arm/include/asm/dma-mapping.h | 2 +- arch/arm/mm/dma-mapping.c | 220 +++++++----------------------------- include/linux/vmalloc.h | 10 +- mm/vmalloc.c | 31 ++++-- 4 files changed, 67 insertions(+), 196 deletions(-) -- 1.7.1.569.g6f426

12 years, 8 months

Jump to page:

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

Linaro-mm-sig