From: Rob Clark <robdclark@gmail.com>
To: dri-devel@lists.freedesktop.org
Cc: Chris Wilson <chris@chris-wilson.co.uk>,
Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
Rob Clark <robdclark@chromium.org>,
David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
Emil Velikov <emil.velikov@collabora.com>,
Eric Anholt <eric@anholt.net>, Eric Biggers <ebiggers@google.com>,
Deepak Sharma <deepak.sharma@amd.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH v3 3/3] drm/vgem: use normal cached mmap'ings
Date: Tue, 16 Jul 2019 14:37:42 -0700 [thread overview]
Message-ID: <20190716213746.4670-3-robdclark@gmail.com> (raw)
In-Reply-To: <20190716213746.4670-1-robdclark@gmail.com>
From: Rob Clark <robdclark@chromium.org>
Since there is no real device associated with VGEM, it is impossible to
end up with appropriate dev->dma_ops, meaning that we have no way to
invalidate the shmem pages allocated by VGEM. So, at least on platforms
without drm_cflush_pages(), we end up with corruption when cache lines
from previous usage of VGEM bo pages get evicted to memory.
The only sane option is to use cached mappings.
Signed-off-by: Rob Clark <robdclark@chromium.org>
---
v3: rebased on drm-tip
drivers/gpu/drm/vgem/vgem_drv.c | 24 ++++++++++++++----------
1 file changed, 14 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c
index e7d12e93b1f0..84262e2bd7f7 100644
--- a/drivers/gpu/drm/vgem/vgem_drv.c
+++ b/drivers/gpu/drm/vgem/vgem_drv.c
@@ -259,9 +259,6 @@ static int vgem_mmap(struct file *filp, struct vm_area_struct *vma)
if (ret)
return ret;
- /* Keep the WC mmaping set by drm_gem_mmap() but our pages
- * are ordinary and not special.
- */
vma->vm_flags = flags | VM_DONTEXPAND | VM_DONTDUMP;
return 0;
}
@@ -310,17 +307,17 @@ static void vgem_unpin_pages(struct drm_vgem_gem_object *bo)
static int vgem_prime_pin(struct drm_gem_object *obj, struct device *dev)
{
struct drm_vgem_gem_object *bo = to_vgem_bo(obj);
- long n_pages = obj->size >> PAGE_SHIFT;
+ long i, n_pages = obj->size >> PAGE_SHIFT;
struct page **pages;
pages = vgem_pin_pages(bo);
if (IS_ERR(pages))
return PTR_ERR(pages);
- /* Flush the object from the CPU cache so that importers can rely
- * on coherent indirect access via the exported dma-address.
- */
- drm_clflush_pages(pages, n_pages);
+ for (i = 0; i < n_pages; i++) {
+ dma_sync_single_for_device(dev, page_to_phys(pages[i]),
+ PAGE_SIZE, DMA_BIDIRECTIONAL);
+ }
return 0;
}
@@ -328,6 +325,13 @@ static int vgem_prime_pin(struct drm_gem_object *obj, struct device *dev)
static void vgem_prime_unpin(struct drm_gem_object *obj, struct device *dev)
{
struct drm_vgem_gem_object *bo = to_vgem_bo(obj);
+ long i, n_pages = obj->size >> PAGE_SHIFT;
+ struct page **pages = bo->pages;
+
+ for (i = 0; i < n_pages; i++) {
+ dma_sync_single_for_cpu(dev, page_to_phys(pages[i]),
+ PAGE_SIZE, DMA_BIDIRECTIONAL);
+ }
vgem_unpin_pages(bo);
}
@@ -382,7 +386,7 @@ static void *vgem_prime_vmap(struct drm_gem_object *obj)
if (IS_ERR(pages))
return NULL;
- return vmap(pages, n_pages, 0, pgprot_writecombine(PAGE_KERNEL));
+ return vmap(pages, n_pages, 0, PAGE_KERNEL);
}
static void vgem_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
@@ -411,7 +415,7 @@ static int vgem_prime_mmap(struct drm_gem_object *obj,
fput(vma->vm_file);
vma->vm_file = get_file(obj->filp);
vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
- vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
+ vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
return 0;
}
--
2.21.0
next prev parent reply other threads:[~2019-07-16 21:45 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-16 21:37 [PATCH v3 1/3] drm/gem: don't force writecombine mmap'ing Rob Clark
2019-07-16 21:37 ` [PATCH v3 2/3] drm: plumb attaching dev thru to prime_pin/unpin Rob Clark
2019-07-17 6:59 ` Koenig, Christian
2019-07-16 21:37 ` Rob Clark [this message]
2019-07-16 23:39 ` [PATCH v3 3/3] drm/vgem: use normal cached mmap'ings Eric Anholt
2019-07-17 0:13 ` Rob Clark
2019-07-19 9:13 ` Daniel Vetter
2019-07-16 23:21 ` [Intel-gfx] [PATCH v3 1/3] drm/gem: don't force writecombine mmap'ing Eric Anholt
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