diff options
Diffstat (limited to 'target/linux/bcm27xx/patches-6.1/950-1166-drm-vc4-Block-swiotlb-bounce-buffers-being-imported-.patch')
| -rw-r--r-- | target/linux/bcm27xx/patches-6.1/950-1166-drm-vc4-Block-swiotlb-bounce-buffers-being-imported-.patch | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/target/linux/bcm27xx/patches-6.1/950-1166-drm-vc4-Block-swiotlb-bounce-buffers-being-imported-.patch b/target/linux/bcm27xx/patches-6.1/950-1166-drm-vc4-Block-swiotlb-bounce-buffers-being-imported-.patch new file mode 100644 index 0000000000..c40b77c957 --- /dev/null +++ b/target/linux/bcm27xx/patches-6.1/950-1166-drm-vc4-Block-swiotlb-bounce-buffers-being-imported-.patch @@ -0,0 +1,84 @@ +From a984fda6b2c24dbf1ca21924f99c8f9418f5765e Mon Sep 17 00:00:00 2001 +From: Dave Stevenson <dave.stevenson@raspberrypi.com> +Date: Wed, 22 Nov 2023 19:17:44 +0000 +Subject: [PATCH] drm: vc4: Block swiotlb bounce buffers being imported as + dmabuf + +The dmabuf import already checks that the backing buffer is contiguous +and rejects it if it isn't. vc4 also requires that the buffer is +in the bottom 1GB of RAM, and this is all correctly defined via +dma-ranges. + +However the kernel silently uses swiotlb to bounce dma buffers +around if they are in the wrong region. This relies on dma sync +functions to be called in order to copy the data to/from the +bounce buffer. + +DRM is based on all memory allocations being coherent with the +GPU so that any updates to a framebuffer will be acted on without +the need for any additional update. This is fairly fundamentally +incompatible with needing to call dma_sync_ to handle the bounce +buffer copies, and therefore we have to detect and reject mappings +that use bounce buffers. + +Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com> +--- + drivers/gpu/drm/vc4/vc4_drv.c | 26 ++++++++++++++++++++++++-- + 1 file changed, 24 insertions(+), 2 deletions(-) + +--- a/drivers/gpu/drm/vc4/vc4_drv.c ++++ b/drivers/gpu/drm/vc4/vc4_drv.c +@@ -29,6 +29,7 @@ + #include <linux/of_platform.h> + #include <linux/platform_device.h> + #include <linux/pm_runtime.h> ++#include <linux/dma-direct.h> + + #include <drm/drm_aperture.h> + #include <drm/drm_atomic_helper.h> +@@ -175,6 +176,19 @@ static void vc4_close(struct drm_device + kfree(vc4file); + } + ++struct drm_gem_object * ++vc4_prime_import_sg_table(struct drm_device *dev, ++ struct dma_buf_attachment *attach, ++ struct sg_table *sgt) ++{ ++ phys_addr_t phys = dma_to_phys(dev->dev, sg_dma_address(sgt->sgl)); ++ ++ if (is_swiotlb_buffer(dev->dev, phys)) ++ return ERR_PTR(-EINVAL); ++ ++ return drm_gem_dma_prime_import_sg_table(dev, attach, sgt); ++} ++ + DEFINE_DRM_GEM_FOPS(vc4_drm_fops); + + static const struct drm_ioctl_desc vc4_drm_ioctls[] = { +@@ -211,7 +225,11 @@ const struct drm_driver vc4_drm_driver = + + .gem_create_object = vc4_create_object, + +- DRM_GEM_DMA_DRIVER_OPS_WITH_DUMB_CREATE(vc4_bo_dumb_create), ++ .dumb_create = vc4_bo_dumb_create, ++ .prime_handle_to_fd = drm_gem_prime_handle_to_fd, ++ .prime_fd_to_handle = drm_gem_prime_fd_to_handle, ++ .gem_prime_import_sg_table = vc4_prime_import_sg_table, ++ .gem_prime_mmap = drm_gem_prime_mmap, + + .ioctls = vc4_drm_ioctls, + .num_ioctls = ARRAY_SIZE(vc4_drm_ioctls), +@@ -234,7 +252,11 @@ const struct drm_driver vc5_drm_driver = + .debugfs_init = vc4_debugfs_init, + #endif + +- DRM_GEM_DMA_DRIVER_OPS_WITH_DUMB_CREATE(vc5_dumb_create), ++ .dumb_create = vc5_dumb_create, ++ .prime_handle_to_fd = drm_gem_prime_handle_to_fd, ++ .prime_fd_to_handle = drm_gem_prime_fd_to_handle, ++ .gem_prime_import_sg_table = vc4_prime_import_sg_table, ++ .gem_prime_mmap = drm_gem_prime_mmap, + + .fops = &vc4_drm_fops, + |