Linaro-mm-sig

linaro-mm-sig@lists.linaro.org

5 participants
2541 discussions

[PATCH] dma-buf: balance refcount inbalance

by jglisse＠redhat.com

From: Jérôme Glisse <jglisse(a)redhat.com> The debugfs take reference on fence without dropping them. Signed-off-by: Jérôme Glisse <jglisse(a)redhat.com> Cc: Christian König <christian.koenig(a)amd.com> Cc: Daniel Vetter <daniel.vetter(a)ffwll.ch> Cc: Sumit Semwal <sumit.semwal(a)linaro.org> Cc: linux-media(a)vger.kernel.org Cc: dri-devel(a)lists.freedesktop.org Cc: linaro-mm-sig(a)lists.linaro.org Cc: Stéphane Marchesin <marcheu(a)chromium.org> Cc: stable(a)vger.kernel.org --- drivers/dma-buf/dma-buf.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 13884474d158..69842145c223 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -1069,6 +1069,7 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused) fence->ops->get_driver_name(fence), fence->ops->get_timeline_name(fence), dma_fence_is_signaled(fence) ? "" : "un"); + dma_fence_put(fence); } rcu_read_unlock(); -- 2.17.2

6 years, 1 month

[PATCH] dma-buf: fix debugfs versus rcu and fence dumping

by jglisse＠redhat.com

From: Jérôme Glisse <jglisse(a)redhat.com> The debugfs take reference on fence without dropping them. Also the rcu section are not well balance. Fix all that ... Signed-off-by: Jérôme Glisse <jglisse(a)redhat.com> Cc: Christian König <christian.koenig(a)amd.com> Cc: Daniel Vetter <daniel.vetter(a)ffwll.ch> Cc: Sumit Semwal <sumit.semwal(a)linaro.org> Cc: linux-media(a)vger.kernel.org Cc: dri-devel(a)lists.freedesktop.org Cc: linaro-mm-sig(a)lists.linaro.org Cc: Stéphane Marchesin <marcheu(a)chromium.org> Cc: stable(a)vger.kernel.org --- drivers/dma-buf/dma-buf.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 13884474d158..f6f4de42ac49 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -1051,24 +1051,31 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused) fobj = rcu_dereference(robj->fence); shared_count = fobj ? fobj->shared_count : 0; fence = rcu_dereference(robj->fence_excl); + fence = dma_fence_get_rcu(fence); if (!read_seqcount_retry(&robj->seq, seq)) break; rcu_read_unlock(); } - - if (fence) + if (fence) { seq_printf(s, "\tExclusive fence: %s %s %ssignalled\n", fence->ops->get_driver_name(fence), fence->ops->get_timeline_name(fence), dma_fence_is_signaled(fence) ? "" : "un"); + dma_fence_put(fence); + } + + rcu_read_lock(); for (i = 0; i < shared_count; i++) { fence = rcu_dereference(fobj->shared[i]); if (!dma_fence_get_rcu(fence)) continue; + rcu_read_unlock(); seq_printf(s, "\tShared fence: %s %s %ssignalled\n", fence->ops->get_driver_name(fence), fence->ops->get_timeline_name(fence), dma_fence_is_signaled(fence) ? "" : "un"); + dma_fence_put(fence); + rcu_read_lock(); } rcu_read_unlock(); -- 2.17.2

6 years, 1 month

Re: [Linaro-mm-sig] [PATCH] staging: android: ion: Remove unused header files

by Laura Abbott

On 11/30/18 6:43 AM, Yangtao Li wrote: > seq_file.h does not need to be included,so remove it. > Acked-by: Laura Abbott <labbott(a)redhat.com> > Signed-off-by: Yangtao Li <tiny.windzz(a)gmail.com> > --- > drivers/staging/android/ion/ion.c | 1 - > drivers/staging/android/ion/ion_system_heap.c | 1 - > 2 files changed, 2 deletions(-) > > diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c > index 99073325b0c0..0d61e9cd0887 100644 > --- a/drivers/staging/android/ion/ion.c > +++ b/drivers/staging/android/ion/ion.c > @@ -23,7 +23,6 @@ > #include <linux/mm_types.h> > #include <linux/rbtree.h> > #include <linux/sched/task.h> > -#include <linux/seq_file.h> > #include <linux/slab.h> > #include <linux/uaccess.h> > #include <linux/vmalloc.h> > diff --git a/drivers/staging/android/ion/ion_system_heap.c b/drivers/staging/android/ion/ion_system_heap.c > index 548bb02c0ca6..9ce2c0d7ac17 100644 > --- a/drivers/staging/android/ion/ion_system_heap.c > +++ b/drivers/staging/android/ion/ion_system_heap.c > @@ -11,7 +11,6 @@ > #include <linux/highmem.h> > #include <linux/mm.h> > #include <linux/scatterlist.h> > -#include <linux/seq_file.h> > #include <linux/slab.h> > #include <linux/vmalloc.h> > #include "ion.h" >

6 years, 1 month

[RFC] android: ion: How to properly clean caches for uncached allocations

by Liam Mark

The issue: Currently in ION if you allocate uncached memory it is possible that there are still dirty lines in the cache. And often these dirty lines in the cache are the zeros which were meant to clear out any sensitive kernel data. What this means is that if you allocate uncached memory from ION, and then subsequently write to that buffer (using the uncached mapping you are provided by ION) then the data you have written could be corrupted at some point in the future if a dirty line is evicted from the cache. Also this means there is a potential security issue. If an un-privileged userspace user allocated uncached memory (for example from the system heap) and then if they were to read from that buffer (through the un-cached mapping they are provided by ION), and if some of the zeros which were written to that memory are still in the cache then this un-privileged userspace user could read potentially sensitive kernel data. An unacceptable fix: I have included some sample code which should resolve this issue for the system heap and the cma heap on some architectures, however this code would not be acceptable for upstreaming since it uses hacks to clean the cache. Similar changes would need to be made to carveout heap and chunk heap. I would appreciate some feedback on the proper way for ION to clean the caches for memory it has allocated that is intended for uncached access. I realize that it may be tempting, as a solution to this problem, to simply strip uncached support from ION. I hope that we can try to find a solution which preserves uncached memory support as ION uncached memory is often used (though perhaps not in upstreamed code) in cases such as multimedia use cases where there is no CPU access required, in secure heap allocations, and in some cases where there is minimal CPU access and therefore uncached memory performs better. Signed-off-by: Liam Mark <lmark(a)codeaurora.org> --- drivers/staging/android/ion/ion.c | 16 ++++++++++++++++ drivers/staging/android/ion/ion.h | 5 ++++- drivers/staging/android/ion/ion_cma_heap.c | 3 +++ drivers/staging/android/ion/ion_page_pool.c | 8 ++++++-- drivers/staging/android/ion/ion_system_heap.c | 7 ++++++- 5 files changed, 35 insertions(+), 4 deletions(-) diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c index 57e0d8035b2e..10e967b0a0f4 100644 --- a/drivers/staging/android/ion/ion.c +++ b/drivers/staging/android/ion/ion.c @@ -38,6 +38,22 @@ bool ion_buffer_cached(struct ion_buffer *buffer) return !!(buffer->flags & ION_FLAG_CACHED); } +void ion_pages_sync_for_device(struct page *page, size_t size, + enum dma_data_direction dir) +{ + struct scatterlist sg; + struct device dev = {0}; + + /* hack, use dummy device */ + arch_setup_dma_ops(&dev, 0, 0, NULL, false); + + sg_init_table(&sg, 1); + sg_set_page(&sg, page, size, 0); + /* hack, use phys address for dma address */ + sg_dma_address(&sg) = page_to_phys(page); + dma_sync_sg_for_device(&dev, &sg, 1, dir); +} + /* this function should only be called while dev->lock is held */ static void ion_buffer_add(struct ion_device *dev, struct ion_buffer *buffer) diff --git a/drivers/staging/android/ion/ion.h b/drivers/staging/android/ion/ion.h index a238f23c9116..227b9928d185 100644 --- a/drivers/staging/android/ion/ion.h +++ b/drivers/staging/android/ion/ion.h @@ -192,6 +192,9 @@ struct ion_heap { */ bool ion_buffer_cached(struct ion_buffer *buffer); +void ion_pages_sync_for_device(struct page *page, size_t size, + enum dma_data_direction dir); + /** * ion_buffer_fault_user_mappings - fault in user mappings of this buffer * @buffer: buffer @@ -333,7 +336,7 @@ struct ion_page_pool { struct ion_page_pool *ion_page_pool_create(gfp_t gfp_mask, unsigned int order, bool cached); void ion_page_pool_destroy(struct ion_page_pool *pool); -struct page *ion_page_pool_alloc(struct ion_page_pool *pool); +struct page *ion_page_pool_alloc(struct ion_page_pool *pool, bool *from_pool); void ion_page_pool_free(struct ion_page_pool *pool, struct page *page); /** ion_page_pool_shrink - shrinks the size of the memory cached in the pool diff --git a/drivers/staging/android/ion/ion_cma_heap.c b/drivers/staging/android/ion/ion_cma_heap.c index 49718c96bf9e..82e80621d114 100644 --- a/drivers/staging/android/ion/ion_cma_heap.c +++ b/drivers/staging/android/ion/ion_cma_heap.c @@ -59,6 +59,9 @@ static int ion_cma_allocate(struct ion_heap *heap, struct ion_buffer *buffer, memset(page_address(pages), 0, size); } + if (!ion_buffer_cached(buffer)) + ion_pages_sync_for_device(pages, size, DMA_BIDIRECTIONAL); + table = kmalloc(sizeof(*table), GFP_KERNEL); if (!table) goto err; diff --git a/drivers/staging/android/ion/ion_page_pool.c b/drivers/staging/android/ion/ion_page_pool.c index b3017f12835f..169a321778ed 100644 --- a/drivers/staging/android/ion/ion_page_pool.c +++ b/drivers/staging/android/ion/ion_page_pool.c @@ -63,7 +63,7 @@ static struct page *ion_page_pool_remove(struct ion_page_pool *pool, bool high) return page; } -struct page *ion_page_pool_alloc(struct ion_page_pool *pool) +struct page *ion_page_pool_alloc(struct ion_page_pool *pool, bool *from_pool) { struct page *page = NULL; @@ -76,8 +76,12 @@ struct page *ion_page_pool_alloc(struct ion_page_pool *pool) page = ion_page_pool_remove(pool, false); mutex_unlock(&pool->mutex); - if (!page) + if (!page) { page = ion_page_pool_alloc_pages(pool); + *from_pool = false; + } else { + *from_pool = true; + } return page; } diff --git a/drivers/staging/android/ion/ion_system_heap.c b/drivers/staging/android/ion/ion_system_heap.c index bc19cdd30637..3bb4604e032b 100644 --- a/drivers/staging/android/ion/ion_system_heap.c +++ b/drivers/staging/android/ion/ion_system_heap.c @@ -57,13 +57,18 @@ static struct page *alloc_buffer_page(struct ion_system_heap *heap, bool cached = ion_buffer_cached(buffer); struct ion_page_pool *pool; struct page *page; + bool from_pool; if (!cached) pool = heap->uncached_pools[order_to_index(order)]; else pool = heap->cached_pools[order_to_index(order)]; - page = ion_page_pool_alloc(pool); + page = ion_page_pool_alloc(pool, &from_pool); + + if (!from_pool && !ion_buffer_cached(buffer)) + ion_pages_sync_for_device(page, PAGE_SIZE << order, + DMA_BIDIRECTIONAL); return page; } -- 1.8.5.2 Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project

6 years, 1 month

Re: [Linaro-mm-sig] [PATCH] udmabuf: set read/write flag when exporting

by Gerd Hoffmann

On Thu, Nov 15, 2018 at 05:46:30PM -0800, Gurchetan Singh wrote: > Reviewed-by: Gurchetan Singh <gurchetansingh(a)chromium.org> > Tested-by: Gurchetan Singh <gurchetansingh(a)chromium.org> Thanks. Pushed to drm-misc-fixes. cheers, Gerd

6 years, 1 month

[PATCH] udmabuf: set read/write flag when exporting

by Gerd Hoffmann

Otherwise, mmap fails when done with PROT_WRITE. Suggested-by: Gurchetan Singh <gurchetansingh(a)chromium.org> Signed-off-by: Gerd Hoffmann <kraxel(a)redhat.com> --- drivers/dma-buf/udmabuf.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index e70328ab7e..d9ff246093 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -189,6 +189,7 @@ static long udmabuf_create(const struct udmabuf_create_list *head, exp_info.ops = &udmabuf_ops; exp_info.size = ubuf->pagecount << PAGE_SHIFT; exp_info.priv = ubuf; + exp_info.flags = O_RDWR; buf = dma_buf_export(&exp_info); if (IS_ERR(buf)) { -- 2.9.3

6 years, 1 month

Re: [Linaro-mm-sig] [PATCH 1/8] dma-buf: remove shared fence staging in reservation object

by Christian König

Ping! Adding a few people directly and more mailing lists. Can I get an acked-by/rb for this? It's only a cleanup and not much functional change. Regards, Christian. Am 04.10.2018 um 15:12 schrieb Christian König: > No need for that any more. Just replace the list when there isn't enough > room any more for the additional fence. > > Signed-off-by: Christian König <christian.koenig(a)amd.com> > --- > drivers/dma-buf/reservation.c | 178 ++++++++++++++---------------------------- > include/linux/reservation.h | 4 - > 2 files changed, 58 insertions(+), 124 deletions(-) > > diff --git a/drivers/dma-buf/reservation.c b/drivers/dma-buf/reservation.c > index 6c95f61a32e7..5825fc336a13 100644 > --- a/drivers/dma-buf/reservation.c > +++ b/drivers/dma-buf/reservation.c > @@ -68,105 +68,23 @@ EXPORT_SYMBOL(reservation_seqcount_string); > */ > int reservation_object_reserve_shared(struct reservation_object *obj) > { > - struct reservation_object_list *fobj, *old; > - u32 max; > + struct reservation_object_list *old, *new; > + unsigned int i, j, k, max; > > old = reservation_object_get_list(obj); > > if (old && old->shared_max) { > - if (old->shared_count < old->shared_max) { > - /* perform an in-place update */ > - kfree(obj->staged); > - obj->staged = NULL; > + if (old->shared_count < old->shared_max) > return 0; > - } else > + else > max = old->shared_max * 2; > - } else > - max = 4; > - > - /* > - * resize obj->staged or allocate if it doesn't exist, > - * noop if already correct size > - */ > - fobj = krealloc(obj->staged, offsetof(typeof(*fobj), shared[max]), > - GFP_KERNEL); > - if (!fobj) > - return -ENOMEM; > - > - obj->staged = fobj; > - fobj->shared_max = max; > - return 0; > -} > -EXPORT_SYMBOL(reservation_object_reserve_shared); > - > -static void > -reservation_object_add_shared_inplace(struct reservation_object *obj, > - struct reservation_object_list *fobj, > - struct dma_fence *fence) > -{ > - struct dma_fence *signaled = NULL; > - u32 i, signaled_idx; > - > - dma_fence_get(fence); > - > - preempt_disable(); > - write_seqcount_begin(&obj->seq); > - > - for (i = 0; i < fobj->shared_count; ++i) { > - struct dma_fence *old_fence; > - > - old_fence = rcu_dereference_protected(fobj->shared[i], > - reservation_object_held(obj)); > - > - if (old_fence->context == fence->context) { > - /* memory barrier is added by write_seqcount_begin */ > - RCU_INIT_POINTER(fobj->shared[i], fence); > - write_seqcount_end(&obj->seq); > - preempt_enable(); > - > - dma_fence_put(old_fence); > - return; > - } > - > - if (!signaled && dma_fence_is_signaled(old_fence)) { > - signaled = old_fence; > - signaled_idx = i; > - } > - } > - > - /* > - * memory barrier is added by write_seqcount_begin, > - * fobj->shared_count is protected by this lock too > - */ > - if (signaled) { > - RCU_INIT_POINTER(fobj->shared[signaled_idx], fence); > } else { > - BUG_ON(fobj->shared_count >= fobj->shared_max); > - RCU_INIT_POINTER(fobj->shared[fobj->shared_count], fence); > - fobj->shared_count++; > + max = 4; > } > > - write_seqcount_end(&obj->seq); > - preempt_enable(); > - > - dma_fence_put(signaled); > -} > - > -static void > -reservation_object_add_shared_replace(struct reservation_object *obj, > - struct reservation_object_list *old, > - struct reservation_object_list *fobj, > - struct dma_fence *fence) > -{ > - unsigned i, j, k; > - > - dma_fence_get(fence); > - > - if (!old) { > - RCU_INIT_POINTER(fobj->shared[0], fence); > - fobj->shared_count = 1; > - goto done; > - } > + new = kmalloc(offsetof(typeof(*new), shared[max]), GFP_KERNEL); > + if (!new) > + return -ENOMEM; > > /* > * no need to bump fence refcounts, rcu_read access > @@ -174,46 +92,45 @@ reservation_object_add_shared_replace(struct reservation_object *obj, > * references from the old struct are carried over to > * the new. > */ > - for (i = 0, j = 0, k = fobj->shared_max; i < old->shared_count; ++i) { > - struct dma_fence *check; > + for (i = 0, j = 0, k = max; i < (old ? old->shared_count : 0); ++i) { > + struct dma_fence *fence; > > - check = rcu_dereference_protected(old->shared[i], > - reservation_object_held(obj)); > - > - if (check->context == fence->context || > - dma_fence_is_signaled(check)) > - RCU_INIT_POINTER(fobj->shared[--k], check); > + fence = rcu_dereference_protected(old->shared[i], > + reservation_object_held(obj)); > + if (dma_fence_is_signaled(fence)) > + RCU_INIT_POINTER(new->shared[--k], fence); > else > - RCU_INIT_POINTER(fobj->shared[j++], check); > + RCU_INIT_POINTER(new->shared[j++], fence); > } > - fobj->shared_count = j; > - RCU_INIT_POINTER(fobj->shared[fobj->shared_count], fence); > - fobj->shared_count++; > + new->shared_count = j; > + new->shared_max = max; > > -done: > preempt_disable(); > write_seqcount_begin(&obj->seq); > /* > * RCU_INIT_POINTER can be used here, > * seqcount provides the necessary barriers > */ > - RCU_INIT_POINTER(obj->fence, fobj); > + RCU_INIT_POINTER(obj->fence, new); > write_seqcount_end(&obj->seq); > preempt_enable(); > > if (!old) > - return; > + return 0; > > /* Drop the references to the signaled fences */ > - for (i = k; i < fobj->shared_max; ++i) { > - struct dma_fence *f; > + for (i = k; i < new->shared_max; ++i) { > + struct dma_fence *fence; > > - f = rcu_dereference_protected(fobj->shared[i], > - reservation_object_held(obj)); > - dma_fence_put(f); > + fence = rcu_dereference_protected(new->shared[i], > + reservation_object_held(obj)); > + dma_fence_put(fence); > } > kfree_rcu(old, rcu); > + > + return 0; > } > +EXPORT_SYMBOL(reservation_object_reserve_shared); > > /** > * reservation_object_add_shared_fence - Add a fence to a shared slot > @@ -226,15 +143,39 @@ reservation_object_add_shared_replace(struct reservation_object *obj, > void reservation_object_add_shared_fence(struct reservation_object *obj, > struct dma_fence *fence) > { > - struct reservation_object_list *old, *fobj = obj->staged; > + struct reservation_object_list *fobj; > + unsigned int i; > > - old = reservation_object_get_list(obj); > - obj->staged = NULL; > + dma_fence_get(fence); > + > + fobj = reservation_object_get_list(obj); > > - if (!fobj) > - reservation_object_add_shared_inplace(obj, old, fence); > - else > - reservation_object_add_shared_replace(obj, old, fobj, fence); > + preempt_disable(); > + write_seqcount_begin(&obj->seq); > + > + for (i = 0; i < fobj->shared_count; ++i) { > + struct dma_fence *old_fence; > + > + old_fence = rcu_dereference_protected(fobj->shared[i], > + reservation_object_held(obj)); > + if (old_fence->context == fence->context || > + dma_fence_is_signaled(old_fence)) { > + dma_fence_put(old_fence); > + goto replace; > + } > + } > + > + BUG_ON(fobj->shared_count >= fobj->shared_max); > + fobj->shared_count++; > + > +replace: > + /* > + * memory barrier is added by write_seqcount_begin, > + * fobj->shared_count is protected by this lock too > + */ > + RCU_INIT_POINTER(fobj->shared[i], fence); > + write_seqcount_end(&obj->seq); > + preempt_enable(); > } > EXPORT_SYMBOL(reservation_object_add_shared_fence); > > @@ -343,9 +284,6 @@ int reservation_object_copy_fences(struct reservation_object *dst, > new = dma_fence_get_rcu_safe(&src->fence_excl); > rcu_read_unlock(); > > - kfree(dst->staged); > - dst->staged = NULL; > - > src_list = reservation_object_get_list(dst); > old = reservation_object_get_excl(dst); > > diff --git a/include/linux/reservation.h b/include/linux/reservation.h > index 02166e815afb..54cf6773a14c 100644 > --- a/include/linux/reservation.h > +++ b/include/linux/reservation.h > @@ -68,7 +68,6 @@ struct reservation_object_list { > * @seq: sequence count for managing RCU read-side synchronization > * @fence_excl: the exclusive fence, if there is one currently > * @fence: list of current shared fences > - * @staged: staged copy of shared fences for RCU updates > */ > struct reservation_object { > struct ww_mutex lock; > @@ -76,7 +75,6 @@ struct reservation_object { > > struct dma_fence __rcu *fence_excl; > struct reservation_object_list __rcu *fence; > - struct reservation_object_list *staged; > }; > > #define reservation_object_held(obj) lockdep_is_held(&(obj)->lock.base) > @@ -95,7 +93,6 @@ reservation_object_init(struct reservation_object *obj) > __seqcount_init(&obj->seq, reservation_seqcount_string, &reservation_seqcount_class); > RCU_INIT_POINTER(obj->fence, NULL); > RCU_INIT_POINTER(obj->fence_excl, NULL); > - obj->staged = NULL; > } > > /** > @@ -124,7 +121,6 @@ reservation_object_fini(struct reservation_object *obj) > > kfree(fobj); > } > - kfree(obj->staged); > > ww_mutex_destroy(&obj->lock); > }

6 years, 2 months

[PATCH] udmabuf: fix error code in map_udmabuf()

by Dan Carpenter

We accidentally forgot to set "ret" on this error path so it means we return NULL instead of an error pointer. The caller checks for NULL and changes it to an error pointer so it doesn't cause an issue at run time. Signed-off-by: Dan Carpenter <dan.carpenter(a)oracle.com> diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index 9edabce0b8ab..5b44ef226904 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -61,8 +61,10 @@ static struct sg_table *map_udmabuf(struct dma_buf_attachment *at, GFP_KERNEL); if (ret < 0) goto err; - if (!dma_map_sg(at->dev, sg->sgl, sg->nents, direction)) + if (!dma_map_sg(at->dev, sg->sgl, sg->nents, direction)) { + ret = -EINVAL; goto err; + } return sg; err:

6 years, 4 months

Re: [Linaro-mm-sig] [PATCH v2 05/17] compat_ioctl: move more drivers to generic_compat_ioctl_ptrarg

by Greg Kroah-Hartman

On Wed, Sep 12, 2018 at 05:08:52PM +0200, Arnd Bergmann wrote: > The .ioctl and .compat_ioctl file operations have the same prototype so > they can both point to the same function, which works great almost all > the time when all the commands are compatible. > > One exception is the s390 architecture, where a compat pointer is only > 31 bit wide, and converting it into a 64-bit pointer requires calling > compat_ptr(). Most drivers here will ever run in s390, but since we now > have a generic helper for it, it's easy enough to use it consistently. > > I double-checked all these drivers to ensure that all ioctl arguments > are used as pointers or are ignored, but are not interpreted as integer > values. > > Signed-off-by: Arnd Bergmann <arnd(a)arndb.de> Acked-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>

6 years, 4 months

[PATCH v3 1/3] udmabuf: add documentation

by Gerd Hoffmann

Signed-off-by: Gerd Hoffmann <kraxel(a)redhat.com> --- include/uapi/linux/udmabuf.h | 51 +++++++++++++++++++++++++++++++++--- Documentation/driver-api/dma-buf.rst | 8 ++++++ 2 files changed, 56 insertions(+), 3 deletions(-) diff --git a/include/uapi/linux/udmabuf.h b/include/uapi/linux/udmabuf.h index 46b6532ed8..281e2c52f1 100644 --- a/include/uapi/linux/udmabuf.h +++ b/include/uapi/linux/udmabuf.h @@ -5,8 +5,39 @@ #include <linux/types.h> #include <linux/ioctl.h> +/** + * DOC: udmabuf + * + * udmabuf is a device driver which allows userspace to create + * dmabufs. The memory used for these dmabufs must be backed by + * memfd. The memfd must have F_SEAL_SHRINK and it must not have + * F_SEAL_WRITE. + * + * The driver has two ioctls, one to create a dmabuf from a single + * memory block and one to create a dmabuf from a list of memory + * blocks. + * + * UDMABUF_CREATE - _IOW('u', 0x42, udmabuf_create) + * + * UDMABUF_CREATE_LIST - _IOW('u', 0x43, udmabuf_create_list) + */ + +#define UDMABUF_CREATE _IOW('u', 0x42, struct udmabuf_create) +#define UDMABUF_CREATE_LIST _IOW('u', 0x43, struct udmabuf_create_list) + #define UDMABUF_FLAGS_CLOEXEC 0x01 +/** + * struct udmabuf_create - create a dmabuf from a single memory block. + * + * @memfd: The file handle. + * @offset: Start of the buffer (from memfd start). + * Must be page aligned. + * @size: Size of the buffer. Must be rounded to page size. + * + * @flags: + * UDMABUF_FLAGS_CLOEXEC: set CLOEXEC flag for the dmabuf. + */ struct udmabuf_create { __u32 memfd; __u32 flags; @@ -14,6 +45,14 @@ struct udmabuf_create { __u64 size; }; +/** + * struct udmabuf_create_item - one memory block list item. + * + * @memfd: The file handle. + * @offset: Start of the buffer (from memfd start). + * Must be page aligned. + * @size: Size of the buffer. Must be rounded to page size. + */ struct udmabuf_create_item { __u32 memfd; __u32 __pad; @@ -21,13 +60,19 @@ struct udmabuf_create_item { __u64 size; }; +/** + * struct udmabuf_create_list - create a dmabuf from a memory block list. + * + * @count: The number of list elements. + * @list: The memory block list + * + * flags: + * UDMABUF_FLAGS_CLOEXEC: set CLOEXEC flag for the dmabuf. + */ struct udmabuf_create_list { __u32 flags; __u32 count; struct udmabuf_create_item list[]; }; -#define UDMABUF_CREATE _IOW('u', 0x42, struct udmabuf_create) -#define UDMABUF_CREATE_LIST _IOW('u', 0x43, struct udmabuf_create_list) - #endif /* _UAPI_LINUX_UDMABUF_H */ diff --git a/Documentation/driver-api/dma-buf.rst b/Documentation/driver-api/dma-buf.rst index b541e97c7a..1f62c30a14 100644 --- a/Documentation/driver-api/dma-buf.rst +++ b/Documentation/driver-api/dma-buf.rst @@ -166,3 +166,11 @@ DMA Fence uABI/Sync File .. kernel-doc:: include/linux/sync_file.h :internal: +Userspace DMA Buffer driver +~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +.. kernel-doc:: include/uapi/linux/udmabuf.h + :doc: udmabuf + +.. kernel-doc:: include/uapi/linux/udmabuf.h + :internal: -- 2.9.3

6 years, 4 months

Jump to page:

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

Linaro-mm-sig