This patch set started out as a single patch with a trivial bit of boilerplate to add dmabuf mmap support to the msm driver. However Rob Clark pointed out that, rather than keep one of the tricks I had used, it would be better to change the helpers resulting in this series.
I've tested this both with a rather hacked about Android userspace and with a fairly small test case run from debian. Both bits of code currently use dumb buffers.
Thanks to Benjamin Gaignard for his help in finding this bit of code and to Damien Hobson-Garcia for pointing out that I'd forgotten (since 3.18) to RESEND these patches.
Dave: I guess its probably too late in the dev. cycle to take this code but don't worry, I will try really hard to remember to RESEND it for 4.2. ;-)
v2:
* Modified DRM_PRIME_HANDLE_TO_FD to honour the O_RDRW from the user and removed code to workaround this from the sti driver (Rob Clark).
* Added a patch to (rather spartanly) document gem_prime_mmap. Only tacked into this series 'cos I spotted it was missing when I was checking whether I needed to describe DRM_RDRW anywhere.
Daniel Thompson (2): drm: prime: Honour O_RDWR during prime-handle-to-fd drm: prime: Document gem_prime_mmap
drivers/gpu/drm/drm_prime.c | 13 ++++++------- include/uapi/drm/drm.h | 1 + 2 files changed, 7 insertions(+), 7 deletions(-)
-- 2.4.3
Currently DRM_IOCTL_PRIME_HANDLE_TO_FD rejects all flags except (DRM|O)_CLOEXEC making it difficult (maybe impossible) for userspace to mmap() the resulting dma-buf even when this is supported by the DRM driver.
It is trivial to relax the restriction and permit read/write access. This is safe because the flags are seldom touched by drm; mostly they are passed verbatim to dma_buf calls.
Signed-off-by: Daniel Thompson daniel.thompson@linaro.org --- drivers/gpu/drm/drm_prime.c | 9 +++------ include/uapi/drm/drm.h | 1 + 2 files changed, 4 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c index 7fec191b45f7..6d2cf4fb4038 100644 --- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -331,7 +331,7 @@ static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = { * drm_gem_prime_export - helper library implementation of the export callback * @dev: drm_device to export from * @obj: GEM object to export - * @flags: flags like DRM_CLOEXEC + * @flags: flags like DRM_CLOEXEC and DRM_RDWR * * This is the implementation of the gem_prime_export functions for GEM drivers * using the PRIME helpers. @@ -639,14 +639,11 @@ int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data, return -ENOSYS;
/* check flags are valid */ - if (args->flags & ~DRM_CLOEXEC) + if (args->flags & ~(DRM_CLOEXEC | DRM_RDWR)) return -EINVAL;
- /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */ - flags = args->flags & DRM_CLOEXEC; - return dev->driver->prime_handle_to_fd(dev, file_priv, - args->handle, flags, &args->fd); + args->handle, args->flags, &args->fd); }
int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data, diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h index ff6ef62d084b..092fe3fa8ec0 100644 --- a/include/uapi/drm/drm.h +++ b/include/uapi/drm/drm.h @@ -668,6 +668,7 @@ struct drm_set_client_cap { __u64 value; };
+#define DRM_RDWR O_RDWR #define DRM_CLOEXEC O_CLOEXEC struct drm_prime_handle { __u32 handle;
On Fri, Jun 19, 2015 at 02:52:28PM +0100, Daniel Thompson wrote:
Currently DRM_IOCTL_PRIME_HANDLE_TO_FD rejects all flags except (DRM|O)_CLOEXEC making it difficult (maybe impossible) for userspace to mmap() the resulting dma-buf even when this is supported by the DRM driver.
It is trivial to relax the restriction and permit read/write access. This is safe because the flags are seldom touched by drm; mostly they are passed verbatim to dma_buf calls.
Signed-off-by: Daniel Thompson daniel.thompson@linaro.org
drivers/gpu/drm/drm_prime.c | 9 +++------ include/uapi/drm/drm.h | 1 + 2 files changed, 4 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c index 7fec191b45f7..6d2cf4fb4038 100644 --- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -331,7 +331,7 @@ static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
- drm_gem_prime_export - helper library implementation of the export callback
- @dev: drm_device to export from
- @obj: GEM object to export
- @flags: flags like DRM_CLOEXEC
- @flags: flags like DRM_CLOEXEC and DRM_RDWR
- This is the implementation of the gem_prime_export functions for GEM drivers
- using the PRIME helpers.
@@ -639,14 +639,11 @@ int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data, return -ENOSYS; /* check flags are valid */
- if (args->flags & ~DRM_CLOEXEC)
- if (args->flags & ~(DRM_CLOEXEC | DRM_RDWR)) return -EINVAL;
I think we should reject DRM_RDWR if there's no mmap implementation in the underlying dma-buf vfunc table. Or in the gem version of those. Otherwise looks ok to me, if we first resolve the dma-buf userspace mmap coherency issue. -Daniel
- /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
- flags = args->flags & DRM_CLOEXEC;
- return dev->driver->prime_handle_to_fd(dev, file_priv,
args->handle, flags, &args->fd);
args->handle, args->flags, &args->fd);} int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data, diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h index ff6ef62d084b..092fe3fa8ec0 100644 --- a/include/uapi/drm/drm.h +++ b/include/uapi/drm/drm.h @@ -668,6 +668,7 @@ struct drm_set_client_cap { __u64 value; }; +#define DRM_RDWR O_RDWR #define DRM_CLOEXEC O_CLOEXEC struct drm_prime_handle { __u32 handle; -- 2.4.3
dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel
gem_prime_map is not currently described in the DRM manual, lets document it.
Signed-off-by: Daniel Thompson daniel.thompson@linaro.org --- drivers/gpu/drm/drm_prime.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c index 6d2cf4fb4038..3b40a415f45d 100644 --- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -309,7 +309,7 @@ static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = { * Drivers can implement @gem_prime_export and @gem_prime_import in terms of * simpler APIs by using the helper functions @drm_gem_prime_export and * @drm_gem_prime_import. These functions implement dma-buf support in terms of - * five lower-level driver callbacks: + * six lower-level driver callbacks: * * Export callbacks: * @@ -321,6 +321,8 @@ static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = { * * - @gem_prime_vunmap: vunmap a buffer exported by your driver * + * - @gem_prime_mmap (optional): mmap a buffer exported by your driver + * * Import callback: * * - @gem_prime_import_sg_table (import): produce a GEM object from another
On Fri, Jun 19, 2015 at 02:52:29PM +0100, Daniel Thompson wrote:
gem_prime_map is not currently described in the DRM manual, lets document it.
Signed-off-by: Daniel Thompson daniel.thompson@linaro.org
Applied to drm-misc, thanks. -Daniel
drivers/gpu/drm/drm_prime.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c index 6d2cf4fb4038..3b40a415f45d 100644 --- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -309,7 +309,7 @@ static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
- Drivers can implement @gem_prime_export and @gem_prime_import in terms of
- simpler APIs by using the helper functions @drm_gem_prime_export and
- @drm_gem_prime_import. These functions implement dma-buf support in terms of
- five lower-level driver callbacks:
- six lower-level driver callbacks:
- Export callbacks:
@@ -321,6 +321,8 @@ static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
- @gem_prime_vunmap: vunmap a buffer exported by your driver
- @gem_prime_mmap (optional): mmap a buffer exported by your driver
- Import callback:
- @gem_prime_import_sg_table (import): produce a GEM object from another
-- 2.4.3
dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel
On Fri, Jun 19, 2015 at 02:52:27PM +0100, Daniel Thompson wrote:
This patch set started out as a single patch with a trivial bit of boilerplate to add dmabuf mmap support to the msm driver. However Rob Clark pointed out that, rather than keep one of the tricks I had used, it would be better to change the helpers resulting in this series.
I've tested this both with a rather hacked about Android userspace and with a fairly small test case run from debian. Both bits of code currently use dumb buffers.
Thanks to Benjamin Gaignard for his help in finding this bit of code and to Damien Hobson-Garcia for pointing out that I'd forgotten (since 3.18) to RESEND these patches.
Dave: I guess its probably too late in the dev. cycle to take this code but don't worry, I will try really hard to remember to RESEND it for 4.2. ;-)
v2:
Modified DRM_PRIME_HANDLE_TO_FD to honour the O_RDRW from the user and removed code to workaround this from the sti driver (Rob Clark).
Added a patch to (rather spartanly) document gem_prime_mmap. Only tacked into this series 'cos I spotted it was missing when I was checking whether I needed to describe DRM_RDRW anywhere.
Oh hornets nest since I just screamed around again against drm prime mmap support ;-) Imo before we expose this for real we really need to somehow figure out what to do about cache coherency. Some intel folks are looking into adding suitable ioctls to the dma-buf fd to make this possible. I think we should wait with enabling drm prime mmaping before that's resolved somehow. I'll point them at your patches though to make sure they don't reinvent this wheel here. -Daniel
Daniel Thompson (2): drm: prime: Honour O_RDWR during prime-handle-to-fd drm: prime: Document gem_prime_mmap
drivers/gpu/drm/drm_prime.c | 13 ++++++------- include/uapi/drm/drm.h | 1 + 2 files changed, 7 insertions(+), 7 deletions(-)
-- 2.4.3
dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel
I'm far of being an expert in cache coherency but, from past experiences, I have notice that ION cache management give good performances and is simple to understand.
ION mark as "dirty" the mapped pages in wm_fault function and check this flag while mapping the buffer in kernel space. If the flag is set it call dma_sync_sg_for_device() with the good direction.
ION allow with an iotcl to do explicit or implicit cache management but, for me, it add complexity to the code when implicit mode should be the preferred one.
Benjamin
2015-06-19 17:48 GMT+02:00 Daniel Vetter daniel@ffwll.ch:
On Fri, Jun 19, 2015 at 02:52:27PM +0100, Daniel Thompson wrote:
This patch set started out as a single patch with a trivial bit of boilerplate to add dmabuf mmap support to the msm driver. However Rob Clark pointed out that, rather than keep one of the tricks I had used, it would be better to change the helpers resulting in this series.
I've tested this both with a rather hacked about Android userspace and with a fairly small test case run from debian. Both bits of code currently use dumb buffers.
Thanks to Benjamin Gaignard for his help in finding this bit of code and to Damien Hobson-Garcia for pointing out that I'd forgotten (since 3.18) to RESEND these patches.
Dave: I guess its probably too late in the dev. cycle to take this code but don't worry, I will try really hard to remember to RESEND it for 4.2. ;-)
v2:
Modified DRM_PRIME_HANDLE_TO_FD to honour the O_RDRW from the user and removed code to workaround this from the sti driver (Rob Clark).
Added a patch to (rather spartanly) document gem_prime_mmap. Only tacked into this series 'cos I spotted it was missing when I was checking whether I needed to describe DRM_RDRW anywhere.
Oh hornets nest since I just screamed around again against drm prime mmap support ;-) Imo before we expose this for real we really need to somehow figure out what to do about cache coherency. Some intel folks are looking into adding suitable ioctls to the dma-buf fd to make this possible. I think we should wait with enabling drm prime mmaping before that's resolved somehow. I'll point them at your patches though to make sure they don't reinvent this wheel here. -Daniel
Daniel Thompson (2): drm: prime: Honour O_RDWR during prime-handle-to-fd drm: prime: Document gem_prime_mmap
drivers/gpu/drm/drm_prime.c | 13 ++++++------- include/uapi/drm/drm.h | 1 + 2 files changed, 7 insertions(+), 7 deletions(-)
-- 2.4.3
dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel
-- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
linaro-kernel@lists.linaro.org
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Benjamin Gaignard -
Daniel Thompson -
Daniel Vetter