Linaro-mm-sig

linaro-mm-sig@lists.linaro.org

5 participants
2544 discussions

Re: [Linaro-mm-sig] [PATCH 10/28] mm: only allow page table mappings for built-in zsmalloc

by Randy Dunlap

On 4/8/20 8:15 AM, Matthew Wilcox wrote: > On Wed, Apr 08, 2020 at 05:12:03PM +0200, Peter Zijlstra wrote: >> On Wed, Apr 08, 2020 at 08:01:00AM -0700, Randy Dunlap wrote: >>> Hi, >>> >>> On 4/8/20 4:59 AM, Christoph Hellwig wrote: >>>> diff --git a/mm/Kconfig b/mm/Kconfig >>>> index 36949a9425b8..614cc786b519 100644 >>>> --- a/mm/Kconfig >>>> +++ b/mm/Kconfig >>>> @@ -702,7 +702,7 @@ config ZSMALLOC >>>> >>>> config ZSMALLOC_PGTABLE_MAPPING >>>> bool "Use page table mapping to access object in zsmalloc" >>>> - depends on ZSMALLOC >>>> + depends on ZSMALLOC=y >>> >>> It's a bool so this shouldn't matter... not needed. >> >> My mm/Kconfig has: >> >> config ZSMALLOC >> tristate "Memory allocator for compressed pages" >> depends on MMU >> >> which I think means it can be modular, no? ack. I misread it. > Randy means that ZSMALLOC_PGTABLE_MAPPING is a bool, so I think hch's patch > is wrong ... if ZSMALLOC is 'm' then ZSMALLOC_PGTABLE_MAPPING would become > 'n' instead of 'y'. sigh, I wish that I had meant that. :) thanks. -- ~Randy

4 years, 9 months

Re: [Linaro-mm-sig] [PATCH 18/28] mm: enforce that vmap can't map pages executable

by Christoph Hellwig

On Wed, Apr 08, 2020 at 01:38:36PM +0100, Mark Rutland wrote: > > +static inline pgprot_t pgprot_nx(pgprot_t prot) > > +{ > > + return __pgprot(pgprot_val(prot) | _PAGE_NX); > > +} > > +#define pgprot_nx pgprot_nx > > + > > #ifdef CONFIG_X86_PAE > > I reckon for arm64 we can do similar in our <asm/pgtable.h>: > > #define pgprot_nx(pgprot_t prot) \ > __pgprot_modify(prot, 0, PTE_PXN) > > ... matching the style of our existing pgprot_*() modifier helpers. I've added that for the next version with attribution to you.

4 years, 9 months

Re: [Linaro-mm-sig] [PATCH] dma-buf: support 32bit DMA_BUF_SET_NAME ioctl

by Sumit Semwal

Hello, Daniel, your comments here, please? On Mon, 24 Feb 2020 at 09:09, Martin Liu <liumartin(a)google.com> wrote: > > On Tue, Jan 14, 2020 at 09:41:01PM +0800, Martin Liu wrote: > > CC more MLs for winder review. > > > This commit adds SET_NAME ioctl coversion to > > support 32 bit ioctl. > > > > Signed-off-by: Martin Liu <liumartin(a)google.com> > > --- > > drivers/dma-buf/dma-buf.c | 22 +++++++++++++++++++++- > > 1 file changed, 21 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c > > index ce41cd9b758a..a73048b34843 100644 > > --- a/drivers/dma-buf/dma-buf.c > > +++ b/drivers/dma-buf/dma-buf.c > > @@ -25,6 +25,7 @@ > > #include <linux/mm.h> > > #include <linux/mount.h> > > #include <linux/pseudo_fs.h> > > +#include <linux/compat.h> > > > > #include <uapi/linux/dma-buf.h> > > #include <uapi/linux/magic.h> > > @@ -409,13 +410,32 @@ static void dma_buf_show_fdinfo(struct seq_file *m, struct file *file) > > dma_resv_unlock(dmabuf->resv); > > } > > > > +#ifdef CONFIG_COMPAT > > +static long dma_buf_ioctl_compat(struct file *file, unsigned int cmd, > > + unsigned long arg) > > +{ > > + switch (_IOC_NR(cmd)) { > > + case _IOC_NR(DMA_BUF_SET_NAME): > > + /* Fix up pointer size*/ > > + if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) { > > + cmd &= ~IOCSIZE_MASK; > > + cmd |= sizeof(void *) << IOCSIZE_SHIFT; > > + } > > + break; > > + } > > + return dma_buf_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); > > +} > > +#endif > > + > > static const struct file_operations dma_buf_fops = { > > .release = dma_buf_release, > > .mmap = dma_buf_mmap_internal, > > .llseek = dma_buf_llseek, > > .poll = dma_buf_poll, > > .unlocked_ioctl = dma_buf_ioctl, > > - .compat_ioctl = compat_ptr_ioctl, > > +#ifdef CONFIG_COMPAT > > + .compat_ioctl = dma_buf_ioctl_compat, > > +#endif > > .show_fdinfo = dma_buf_show_fdinfo, > > }; > > > > -- > > 2.25.0.rc1.283.g88dfdc4193-goog > > -- Thanks and regards, Sumit Semwal Linaro Consumer Group - Kernel Team Lead Linaro.org │ Open source software for ARM SoCs

4 years, 9 months

[PATCH v2] staging: android: ion: Align with parenthesis

by John B. Wyatt IV

Align two different lines of arguments with the parenthesis of their respected function definitions. Fix style warnings of matching alignment. Reported by checkpatch. Signed-off-by: John B. Wyatt IV <jbwyatt4(a)gmail.com> --- v2: Change comment title and summary Suggested-by: Julia Lawall <julia.lawall(a)inria.fr> drivers/staging/android/ion/ion_page_pool.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/staging/android/ion/ion_page_pool.c b/drivers/staging/android/ion/ion_page_pool.c index f85ec5b16b65..0198b886d906 100644 --- a/drivers/staging/android/ion/ion_page_pool.c +++ b/drivers/staging/android/ion/ion_page_pool.c @@ -37,7 +37,7 @@ static void ion_page_pool_add(struct ion_page_pool *pool, struct page *page) } mod_node_page_state(page_pgdat(page), NR_KERNEL_MISC_RECLAIMABLE, - 1 << pool->order); + 1 << pool->order); mutex_unlock(&pool->mutex); } @@ -57,7 +57,7 @@ static struct page *ion_page_pool_remove(struct ion_page_pool *pool, bool high) list_del(&page->lru); mod_node_page_state(page_pgdat(page), NR_KERNEL_MISC_RECLAIMABLE, - -(1 << pool->order)); + -(1 << pool->order)); return page; } -- 2.25.1

4 years, 9 months

[PATCH] staging: android: ion: Fix parenthesis alignment

by John B. Wyatt IV

Fix 2 parenthesis alignment issues. Reported by checkpatch. Signed-off-by: John B. Wyatt IV <jbwyatt4(a)gmail.com> --- drivers/staging/android/ion/ion_page_pool.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/staging/android/ion/ion_page_pool.c b/drivers/staging/android/ion/ion_page_pool.c index f85ec5b16b65..0198b886d906 100644 --- a/drivers/staging/android/ion/ion_page_pool.c +++ b/drivers/staging/android/ion/ion_page_pool.c @@ -37,7 +37,7 @@ static void ion_page_pool_add(struct ion_page_pool *pool, struct page *page) } mod_node_page_state(page_pgdat(page), NR_KERNEL_MISC_RECLAIMABLE, - 1 << pool->order); + 1 << pool->order); mutex_unlock(&pool->mutex); } @@ -57,7 +57,7 @@ static struct page *ion_page_pool_remove(struct ion_page_pool *pool, bool high) list_del(&page->lru); mod_node_page_state(page_pgdat(page), NR_KERNEL_MISC_RECLAIMABLE, - -(1 << pool->order)); + -(1 << pool->order)); return page; } -- 2.25.1

4 years, 9 months

[PATCH] staging: android: ion: Fix parenthesis alignment

by John B. Wyatt IV

4 years, 9 months

[PATCH 1/7] dma-buf: add dynamic DMA-buf handling v15

by Christian König

On the exporter side we add optional explicit pinning callbacks. Which are called when the importer doesn't implement dynamic handling, move notification or need the DMA-buf locked in place for its use case. On the importer side we add an optional move_notify callback. This callback is used by the exporter to inform the importers that their mappings should be destroyed as soon as possible. This allows the exporter to provide the mappings without the need to pin the backing store. v2: don't try to invalidate mappings when the callback is NULL, lock the reservation obj while using the attachments, add helper to set the callback v3: move flag for invalidation support into the DMA-buf, use new attach_info structure to set the callback v4: use importer_priv field instead of mangling exporter priv. v5: drop invalidation_supported flag v6: squash together with pin/unpin changes v7: pin/unpin takes an attachment now v8: nuke dma_buf_attachment_(map|unmap)_locked, everything is now handled backward compatible v9: always cache when export/importer don't agree on dynamic handling v10: minimal style cleanup v11: drop automatically re-entry avoidance v12: rename callback to move_notify v13: add might_lock in appropriate places v14: rebase on separated locking change v15: add EXPERIMENTAL flag, some more code comments Signed-off-by: Christian König <christian.koenig(a)amd.com> --- drivers/dma-buf/Kconfig | 10 ++ drivers/dma-buf/dma-buf.c | 110 ++++++++++++++++++-- drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c | 6 +- include/linux/dma-buf.h | 82 +++++++++++++-- 4 files changed, 188 insertions(+), 20 deletions(-) diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig index e7d820ce0724..ef73b678419c 100644 --- a/drivers/dma-buf/Kconfig +++ b/drivers/dma-buf/Kconfig @@ -39,6 +39,16 @@ config UDMABUF A driver to let userspace turn memfd regions into dma-bufs. Qemu can use this to create host dmabufs for guest framebuffers. +config DMABUF_MOVE_NOTIFY + bool "Move notify between drivers (EXPERIMENTAL)" + default n + help + Don''t pin buffers if the dynamic DMA-buf interface is available on both the + exporter as well as the importer. This fixes a security problem where + userspace is able to pin unrestricted amounts of memory through DMA-buf. + But marked experimental because we don''t jet have a consistent execution + context and memory management between drivers. + config DMABUF_SELFTESTS tristate "Selftests for the dma-buf interfaces" default n diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index d4097856c86b..5f10d1929476 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -527,6 +527,10 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) exp_info->ops->dynamic_mapping)) return ERR_PTR(-EINVAL); + if (WARN_ON(!exp_info->ops->dynamic_mapping && + (exp_info->ops->pin || exp_info->ops->unpin))) + return ERR_PTR(-EINVAL); + if (!try_module_get(exp_info->owner)) return ERR_PTR(-ENOENT); @@ -651,7 +655,8 @@ EXPORT_SYMBOL_GPL(dma_buf_put); * calls attach() of dma_buf_ops to allow device-specific attach functionality * @dmabuf: [in] buffer to attach device to. * @dev: [in] device to be attached. - * @dynamic_mapping: [in] calling convention for map/unmap + * @importer_ops [in] importer operations for the attachment + * @importer_priv [in] importer private pointer for the attachment * * Returns struct dma_buf_attachment pointer for this attachment. Attachments * must be cleaned up by calling dma_buf_detach(). @@ -667,11 +672,13 @@ EXPORT_SYMBOL_GPL(dma_buf_put); */ struct dma_buf_attachment * dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev, - bool dynamic_mapping) + const struct dma_buf_attach_ops *importer_ops, + void *importer_priv) { struct dma_buf_attachment *attach; int ret; + /* TODO: make move_notify mandatory if importer_ops are provided. */ if (WARN_ON(!dmabuf || !dev)) return ERR_PTR(-EINVAL); @@ -681,7 +688,8 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev, attach->dev = dev; attach->dmabuf = dmabuf; - attach->dynamic_mapping = dynamic_mapping; + attach->importer_ops = importer_ops; + attach->importer_priv = importer_priv; if (dmabuf->ops->attach) { ret = dmabuf->ops->attach(dmabuf, attach); @@ -700,15 +708,19 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev, dma_buf_is_dynamic(dmabuf)) { struct sg_table *sgt; - if (dma_buf_is_dynamic(attach->dmabuf)) + if (dma_buf_is_dynamic(attach->dmabuf)) { dma_resv_lock(attach->dmabuf->resv, NULL); + ret = dma_buf_pin(attach); + if (ret) + goto err_unlock; + } sgt = dmabuf->ops->map_dma_buf(attach, DMA_BIDIRECTIONAL); if (!sgt) sgt = ERR_PTR(-ENOMEM); if (IS_ERR(sgt)) { ret = PTR_ERR(sgt); - goto err_unlock; + goto err_unpin; } if (dma_buf_is_dynamic(attach->dmabuf)) dma_resv_unlock(attach->dmabuf->resv); @@ -722,6 +734,10 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev, kfree(attach); return ERR_PTR(ret); +err_unpin: + if (dma_buf_is_dynamic(attach->dmabuf)) + dma_buf_unpin(attach); + err_unlock: if (dma_buf_is_dynamic(attach->dmabuf)) dma_resv_unlock(attach->dmabuf->resv); @@ -742,7 +758,7 @@ EXPORT_SYMBOL_GPL(dma_buf_dynamic_attach); struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, struct device *dev) { - return dma_buf_dynamic_attach(dmabuf, dev, false); + return dma_buf_dynamic_attach(dmabuf, dev, NULL, NULL); } EXPORT_SYMBOL_GPL(dma_buf_attach); @@ -765,8 +781,10 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) dmabuf->ops->unmap_dma_buf(attach, attach->sgt, attach->dir); - if (dma_buf_is_dynamic(attach->dmabuf)) + if (dma_buf_is_dynamic(attach->dmabuf)) { + dma_buf_unpin(attach); dma_resv_unlock(attach->dmabuf->resv); + } } dma_resv_lock(dmabuf->resv, NULL); @@ -779,6 +797,44 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) } EXPORT_SYMBOL_GPL(dma_buf_detach); +/** + * dma_buf_pin - Lock down the DMA-buf + * + * @attach: [in] attachment which should be pinned + * + * Returns: + * 0 on success, negative error code on failure. + */ +int dma_buf_pin(struct dma_buf_attachment *attach) +{ + struct dma_buf *dmabuf = attach->dmabuf; + int ret = 0; + + dma_resv_assert_held(dmabuf->resv); + + if (dmabuf->ops->pin) + ret = dmabuf->ops->pin(attach); + + return ret; +} +EXPORT_SYMBOL_GPL(dma_buf_pin); + +/** + * dma_buf_unpin - Remove lock from DMA-buf + * + * @attach: [in] attachment which should be unpinned + */ +void dma_buf_unpin(struct dma_buf_attachment *attach) +{ + struct dma_buf *dmabuf = attach->dmabuf; + + dma_resv_assert_held(dmabuf->resv); + + if (dmabuf->ops->unpin) + dmabuf->ops->unpin(attach); +} +EXPORT_SYMBOL_GPL(dma_buf_unpin); + /** * dma_buf_map_attachment - Returns the scatterlist table of the attachment; * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the @@ -798,6 +854,7 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach, enum dma_data_direction direction) { struct sg_table *sg_table; + int r; might_sleep(); @@ -819,13 +876,25 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach, return attach->sgt; } - if (dma_buf_is_dynamic(attach->dmabuf)) + if (dma_buf_is_dynamic(attach->dmabuf)) { dma_resv_assert_held(attach->dmabuf->resv); + if (!attach->importer_ops->move_notify || + !IS_ENABLED(CONFIG_DMABUF_MOVE_NOTIFY)) { + r = dma_buf_pin(attach); + if (r) + return ERR_PTR(r); + } + } sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction); if (!sg_table) sg_table = ERR_PTR(-ENOMEM); + if (IS_ERR(sg_table) && dma_buf_is_dynamic(attach->dmabuf) && + (!attach->importer_ops->move_notify || + !IS_ENABLED(CONFIG_DMABUF_MOVE_NOTIFY))) + dma_buf_unpin(attach); + if (!IS_ERR(sg_table) && attach->dmabuf->ops->cache_sgt_mapping) { attach->sgt = sg_table; attach->dir = direction; @@ -864,9 +933,34 @@ void dma_buf_unmap_attachment(struct dma_buf_attachment *attach, dma_resv_assert_held(attach->dmabuf->resv); attach->dmabuf->ops->unmap_dma_buf(attach, sg_table, direction); + + if (dma_buf_is_dynamic(attach->dmabuf) && + (!attach->importer_ops->move_notify || + !IS_ENABLED(CONFIG_DMABUF_MOVE_NOTIFY))) + dma_buf_unpin(attach); } EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment); +/** + * dma_buf_move_notify - notify attachments that DMA-buf is moving + * + * @dmabuf: [in] buffer which is moving + * + * Informs all attachmenst that they need to destroy and recreated all their + * mappings. + */ +void dma_buf_move_notify(struct dma_buf *dmabuf) +{ + struct dma_buf_attachment *attach; + + dma_resv_assert_held(dmabuf->resv); + + list_for_each_entry(attach, &dmabuf->attachments, node) + if (attach->importer_ops && attach->importer_ops->move_notify) + attach->importer_ops->move_notify(attach); +} +EXPORT_SYMBOL_GPL(dma_buf_move_notify); + /** * DOC: cpu access * diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c index a59cd47aa6c1..7cafc65fd76a 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c @@ -412,6 +412,9 @@ amdgpu_dma_buf_create_obj(struct drm_device *dev, struct dma_buf *dma_buf) return ERR_PTR(ret); } +static const struct dma_buf_attach_ops amdgpu_dma_buf_attach_ops = { +}; + /** * amdgpu_gem_prime_import - &drm_driver.gem_prime_import implementation * @dev: DRM device @@ -444,7 +447,8 @@ struct drm_gem_object *amdgpu_gem_prime_import(struct drm_device *dev, if (IS_ERR(obj)) return obj; - attach = dma_buf_dynamic_attach(dma_buf, dev->dev, true); + attach = dma_buf_dynamic_attach(dma_buf, dev->dev, + &amdgpu_dma_buf_attach_ops, NULL); if (IS_ERR(attach)) { drm_gem_object_put(obj); return ERR_CAST(attach); diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index abf5459a5b9d..b38cea240b67 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -93,14 +93,41 @@ struct dma_buf_ops { */ void (*detach)(struct dma_buf *, struct dma_buf_attachment *); + /** + * @pin: + * + * This is called by dma_buf_pin and lets the exporter know that the + * DMA-buf can't be moved any more. + * + * This is called with the dmabuf->resv object locked. + * + * This callback is optional and should only be used in limited use + * cases like scanout and not for temporary pin operations. + * + * Returns: + * + * 0 on success, negative error code on failure. + */ + int (*pin)(struct dma_buf_attachment *attach); + + /** + * @unpin: + * + * This is called by dma_buf_unpin and lets the exporter know that the + * DMA-buf can be moved again. + * + * This is called with the dmabuf->resv object locked. + * + * This callback is optional. + */ + void (*unpin)(struct dma_buf_attachment *attach); + /** * @map_dma_buf: * * This is called by dma_buf_map_attachment() and is used to map a * shared &dma_buf into device address space, and it is mandatory. It - * can only be called if @attach has been called successfully. This - * essentially pins the DMA buffer into place, and it cannot be moved - * any more + * can only be called if @attach has been called successfully. * * This call may sleep, e.g. when the backing storage first needs to be * allocated, or moved to a location suitable for all currently attached @@ -141,9 +168,8 @@ struct dma_buf_ops { * * This is called by dma_buf_unmap_attachment() and should unmap and * release the &sg_table allocated in @map_dma_buf, and it is mandatory. - * It should also unpin the backing storage if this is the last mapping - * of the DMA buffer, it the exporter supports backing storage - * migration. + * For static dma_buf handling this might also unpins the backing + * storage if this is the last mapping of the DMA buffer. */ void (*unmap_dma_buf)(struct dma_buf_attachment *, struct sg_table *, @@ -311,6 +337,34 @@ struct dma_buf { } cb_excl, cb_shared; }; +/** + * struct dma_buf_attach_ops - importer operations for an attachment + * @move_notify: [optional] notification that the DMA-buf is moving + * + * Attachment operations implemented by the importer. + */ +struct dma_buf_attach_ops { + /** + * @move_notify + * + * If this callback is provided the framework can avoid pinning the + * backing store while mappings exists. + * + * This callback is called with the lock of the reservation object + * associated with the dma_buf held and the mapping function must be + * called with this lock held as well. This makes sure that no mapping + * is created concurrently with an ongoing move operation. + * + * Mappings stay valid and are not directly affected by this callback. + * But the DMA-buf can now be in a different physical location, so all + * mappings should be destroyed and re-created as soon as possible. + * + * New mappings can be created after this callback returns, and will + * point to the new location of the DMA-buf. + */ + void (*move_notify)(struct dma_buf_attachment *attach); +}; + /** * struct dma_buf_attachment - holds device-buffer attachment data * @dmabuf: buffer for this attachment. @@ -319,8 +373,9 @@ struct dma_buf { * @sgt: cached mapping. * @dir: direction of cached mapping. * @priv: exporter specific attachment data. - * @dynamic_mapping: true if dma_buf_map/unmap_attachment() is called with the - * dma_resv lock held. + * @importer_ops: importer operations for this attachment, if provided + * dma_buf_map/unmap_attachment() must be called with the dma_resv lock held. + * @importer_priv: importer specific attachment data. * * This structure holds the attachment information between the dma_buf buffer * and its user device(s). The list contains one attachment struct per device @@ -337,7 +392,8 @@ struct dma_buf_attachment { struct list_head node; struct sg_table *sgt; enum dma_data_direction dir; - bool dynamic_mapping; + const struct dma_buf_attach_ops *importer_ops; + void *importer_priv; void *priv; }; @@ -399,6 +455,7 @@ static inline void get_dma_buf(struct dma_buf *dmabuf) */ static inline bool dma_buf_is_dynamic(struct dma_buf *dmabuf) { + /* TODO: switch to using pin/unpin functions as indicator. */ return dmabuf->ops->dynamic_mapping; } @@ -413,16 +470,19 @@ static inline bool dma_buf_is_dynamic(struct dma_buf *dmabuf) static inline bool dma_buf_attachment_is_dynamic(struct dma_buf_attachment *attach) { - return attach->dynamic_mapping; + return !!attach->importer_ops; } struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, struct device *dev); struct dma_buf_attachment * dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev, - bool dynamic_mapping); + const struct dma_buf_attach_ops *importer_ops, + void *importer_priv); void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach); +int dma_buf_pin(struct dma_buf_attachment *attach); +void dma_buf_unpin(struct dma_buf_attachment *attach); struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info); -- 2.17.1

4 years, 9 months

Re: [Linaro-mm-sig] [PATCH v3 0/4] Support virtio cross-device resources

by Gerd Hoffmann

On Wed, Mar 11, 2020 at 08:20:00PM +0900, David Stevens wrote: > This patchset implements the current proposal for virtio cross-device > resource sharing [1], with minor changes based on recent comments. It > is expected that this will be used to import virtio resources into the > virtio-video driver currently under discussion [2]. > > This patchset adds a new hook to dma-buf, for querying the dma-buf's > underlying virtio UUID. This hook is then plumbed through DRM PRIME > buffers, and finally implemented in virtgpu. Looks all fine to me. We should wait for the virtio protocol update (patch 3/4) being accepted into the virtio specification. When this is done I'll go commit this to drm-misc-next. cheers, Gerd

4 years, 10 months

[PATCH] MAINTAINERS: Better regex for dma_buf|fence|resv

by Daniel Vetter

We're getting some random other stuff that we're not really interested in, so match only word boundaries. Also avoid the capture group while at it. Suggested by Joe Perches. Cc: linux-media(a)vger.kernel.org Cc: dri-devel(a)lists.freedesktop.org Cc: linaro-mm-sig(a)lists.linaro.org Cc: Joe Perches <joe(a)perches.com> Cc: Sumit Semwal <sumit.semwal(a)linaro.org> Cc: Sam Ravnborg <sam(a)ravnborg.org> Signed-off-by: Daniel Vetter <daniel.vetter(a)intel.com> --- v2: No single quotes in MAINTAINERS (Joe) v3: Fix typo in commit message (Sam) --- MAINTAINERS | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/MAINTAINERS b/MAINTAINERS index 3005be638c2c..ed6088a01bfe 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -5025,7 +5025,7 @@ F: include/linux/dma-buf* F: include/linux/reservation.h F: include/linux/*fence.h F: Documentation/driver-api/dma-buf.rst -K: dma_(buf|fence|resv) +K: \bdma_(?:buf|fence|resv)\b T: git git://anongit.freedesktop.org/drm/drm-misc DMA-BUF HEAPS FRAMEWORK -- 2.25.1

4 years, 10 months

[PATCH] RFC: dma-buf: Add an API for importing and exporting sync files

by Jason Ekstrand

Explicit synchronization is the future. At least, that seems to be what most userspace APIs are agreeing on at this point. However, most of our Linux APIs (both userspace and kernel UAPI) are currently built around implicit synchronization with dma-buf. While work is ongoing to change many of the userspace APIs and protocols to an explicit synchronization model, switching over piecemeal is difficult due to the number of potential components involved. On the kernel side, many drivers use dma-buf including GPU (3D/compute), display, v4l, and others. In userspace, we have X11, several Wayland compositors, 3D drivers, compute drivers (OpenCL etc.), media encode/decode, and the list goes on. This patch provides a path forward by allowing userspace to manually manage the fences attached to a dma-buf. Alternatively, one can think of this as making dma-buf's implicit synchronization simply a carrier for an explicit fence. This is accomplished by adding two IOCTLs to dma-buf for importing and exporting a sync file to/from the dma-buf. This way a userspace component which is uses explicit synchronization, such as a Vulkan driver, can manually set the write fence on a buffer before handing it off to an implicitly synchronized component such as a Wayland compositor or video encoder. In this way, each of the different components can be upgraded to an explicit synchronization model one at a time as long as the userspace pieces connecting them are aware of it and import/export fences at the right times. There is a potential race condition with this API if userspace is not careful. A typical use case for implicit synchronization is to wait for the dma-buf to be ready, use it, and then signal it for some other component. Because a sync_file cannot be created until it is guaranteed to complete in finite time, userspace can only signal the dma-buf after it has already submitted the work which uses it to the kernel and has received a sync_file back. There is no way to atomically submit a wait-use-signal operation. This is not, however, really a problem with this API so much as it is a problem with explicit synchronization itself. The way this is typically handled is to have very explicit ownership transfer points in the API or protocol which ensure that only one component is using it at any given time. Both X11 (via the PRESENT extension) and Wayland provide such ownership transfer points via explicit present and idle messages. The decision was intentionally made in this patch to make the import and export operations IOCTLs on the dma-buf itself rather than as a DRM IOCTL. This makes it the import/export operation universal across all components which use dma-buf including GPU, display, v4l, and others. It also means that a userspace component can do the import/export without access to the DRM fd which may be tricky to get in cases where the client communicates with DRM via a userspace API such as OpenGL or Vulkan. At a future date we may choose to add direct import/export APIs to components such as drm_syncobj to avoid allocating a file descriptor and going through two ioctls. However, that seems to be something of a micro-optimization as import/export operations are likely to happen at a rate of a few per frame of rendered or decoded video. Signed-off-by: Jason Ekstrand <jason(a)jlekstrand.net> --- This is marked as an RFC because I intend it to start a discussion about how to solve a problem. The current patch compiles but that's it for now. I'll be writing IGT tests and Vulkan driver patches which exercise it over the next couple of days. In the mean time, feel free to tell me why you think this is a great and/or terrible idea. :-) --Jason drivers/dma-buf/dma-buf.c | 115 +++++++++++++++++++++++++++++++++++ include/uapi/linux/dma-buf.h | 13 +++- 2 files changed, 126 insertions(+), 2 deletions(-) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index d4097856c86b..3845b87e209e 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -20,6 +20,7 @@ #include <linux/debugfs.h> #include <linux/module.h> #include <linux/seq_file.h> +#include <linux/sync_file.h> #include <linux/poll.h> #include <linux/dma-resv.h> #include <linux/mm.h> @@ -348,6 +349,114 @@ static long dma_buf_set_name(struct dma_buf *dmabuf, const char __user *buf) return ret; } +static long dma_buf_wait_sync_file(struct dma_buf *dmabuf, + const void __user *user_data) +{ + struct dma_buf_sync_file arg; + struct dma_fence *fence; + + if (copy_from_user(&arg, user_data, sizeof(arg))) + return -EFAULT; + + if (arg.flags != 0 && arg.flags != DMA_BUF_SYNC_FILE_SYNC_WRITE) + return -EINVAL; + + fence = sync_file_get_fence(arg.fd); + if (!fence) + return -EINVAL; + + if (arg.flags & DMA_BUF_SYNC_FILE_SYNC_WRITE) { + dma_resv_add_excl_fence(dmabuf->resv, fence); + } else { + dma_resv_add_shared_fence(dmabuf->resv, fence); + } + + return 0; +} + +static long dma_buf_signal_sync_file(struct dma_buf *dmabuf, + void __user *user_data) +{ + struct dma_buf_sync_file arg; + struct dma_fence *fence = NULL; + struct sync_file *sync_file; + int fd, ret; + + if (copy_from_user(&arg, user_data, sizeof(arg))) + return -EFAULT; + + if (arg.flags != 0 && arg.flags != DMA_BUF_SYNC_FILE_SYNC_WRITE) + return -EINVAL; + + fd = get_unused_fd_flags(O_CLOEXEC); + if (fd < 0) + return fd; + + if (arg.flags & DMA_BUF_SYNC_FILE_SYNC_WRITE) { + /* We need to include both the exclusive fence and all of + * the shared fences in our fence. + */ + struct dma_fence **fences = NULL; + unsigned i, num_fences = 0; + + ret = dma_resv_get_fences_rcu(dmabuf->resv, NULL, + &num_fences, &fences); + if (ret) + goto err_put_fd; + + if (num_fences == 0) { + fence = dma_fence_get_stub(); + } else if (num_fences == 1) { + fence = fences[0]; + kfree(fences); + } else { + struct dma_fence_array *fence_arr; + + fence_arr = dma_fence_array_create(num_fences, fences, + dma_fence_context_alloc(1), + 1, false); + if (!fence_arr) { + for (i = 0; i < num_fences; i++) + dma_fence_put(fences[i]); + kfree(fences); + ret = -ENOMEM; + goto err_put_fd; + } + + /* The fence array now owns fences_arr and our + * references to each of the individual fences. We + * only own a reference to the one array fence. + */ + fence = &fence_arr->base; + } + } else { + fence = dma_resv_get_excl_rcu(dmabuf->resv); + if (!fence) + fence = dma_fence_get_stub(); + } + + sync_file = sync_file_create(fence); + + dma_fence_put(fence); + + if (!sync_file) { + ret = -EINVAL; + goto err_put_fd; + } + + fd_install(fd, sync_file->file); + + arg.fd = fd; + if (copy_to_user(user_data, &arg, sizeof(arg))) + return -EFAULT; + + return 0; + +err_put_fd: + put_unused_fd(fd); + return ret; +} + static long dma_buf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { @@ -390,6 +499,12 @@ static long dma_buf_ioctl(struct file *file, case DMA_BUF_SET_NAME: return dma_buf_set_name(dmabuf, (const char __user *)arg); + case DMA_BUF_IOCTL_WAIT_SYNC_FILE: + return dma_buf_wait_sync_file(dmabuf, (const void __user *)arg); + + case DMA_BUF_IOCTL_SIGNAL_SYNC_FILE: + return dma_buf_signal_sync_file(dmabuf, (void __user *)arg); + default: return -ENOTTY; } diff --git a/include/uapi/linux/dma-buf.h b/include/uapi/linux/dma-buf.h index dbc7092e04b5..825b9a913c89 100644 --- a/include/uapi/linux/dma-buf.h +++ b/include/uapi/linux/dma-buf.h @@ -37,8 +37,17 @@ struct dma_buf_sync { #define DMA_BUF_NAME_LEN 32 +struct dma_buf_sync_file { + __u32 flags; + __s32 fd; +}; + +#define DMA_BUF_SYNC_FILE_SYNC_WRITE (1 << 0) + #define DMA_BUF_BASE 'b' -#define DMA_BUF_IOCTL_SYNC _IOW(DMA_BUF_BASE, 0, struct dma_buf_sync) -#define DMA_BUF_SET_NAME _IOW(DMA_BUF_BASE, 1, const char *) +#define DMA_BUF_IOCTL_SYNC _IOW(DMA_BUF_BASE, 0, struct dma_buf_sync) +#define DMA_BUF_SET_NAME _IOW(DMA_BUF_BASE, 1, const char *) +#define DMA_BUF_IOCTL_WAIT_SYNC_FILE _IOW(DMA_BUF_BASE, 2, struct dma_buf_sync) +#define DMA_BUF_IOCTL_SIGNAL_SYNC_FILE _IOW(DMA_BUF_BASE, 3, struct dma_buf_sync) #endif -- 2.24.1

4 years, 10 months

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