Add the dma_ops for this restricted heap. For restricted buffer,
1) cache_ops/mmap are not allowed, thus return EPERM for them.
2) In map_dma_buf, use DMA_ATTR_SKIP_CPU_SYNC to skip cache sync since
the buffer is protected.
This type buffers are marked by sg_dma_mark_restricted, the user could
check if this is a restricted buffer by sg_dma_is_restricted.
Signed-off-by: Yong Wu <[email protected]>
---
drivers/dma-buf/heaps/restricted_heap.c | 102 ++++++++++++++++++++++++
drivers/dma-buf/heaps/restricted_heap.h | 2 +
2 files changed, 104 insertions(+)
diff --git a/drivers/dma-buf/heaps/restricted_heap.c b/drivers/dma-buf/heaps/restricted_heap.c
index 8bb3c1876a69..4e45d46a6467 100644
--- a/drivers/dma-buf/heaps/restricted_heap.c
+++ b/drivers/dma-buf/heaps/restricted_heap.c
@@ -8,10 +8,16 @@
#include <linux/dma-buf.h>
#include <linux/dma-heap.h>
#include <linux/err.h>
+#include <linux/scatterlist.h>
#include <linux/slab.h>
#include "restricted_heap.h"
+struct restricted_heap_attachment {
+ struct sg_table *table;
+ struct device *dev;
+};
+
static int
restricted_heap_memory_allocate(struct restricted_heap *rheap, struct restricted_buffer *buf)
{
@@ -45,6 +51,101 @@ restricted_heap_memory_free(struct restricted_heap *rheap, struct restricted_buf
ops->free(rheap, buf);
}
+static int restricted_heap_attach(struct dma_buf *dmabuf, struct dma_buf_attachment *attachment)
+{
+ struct restricted_buffer *restricted_buf = dmabuf->priv;
+ struct restricted_heap_attachment *a;
+ struct sg_table *table;
+
+ a = kzalloc(sizeof(*a), GFP_KERNEL);
+ if (!a)
+ return -ENOMEM;
+
+ table = sg_dup_table(&restricted_buf->sg_table);
+ if (!table) {
+ kfree(a);
+ return -ENOMEM;
+ }
+
+ sg_dma_mark_restricted(table->sgl);
+ a->table = table;
+ a->dev = attachment->dev;
+ attachment->priv = a;
+
+ return 0;
+}
+
+static void restricted_heap_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attachment)
+{
+ struct restricted_heap_attachment *a = attachment->priv;
+
+ sg_free_table(a->table);
+ kfree(a->table);
+ kfree(a);
+}
+
+static struct sg_table *
+restricted_heap_map_dma_buf(struct dma_buf_attachment *attachment,
+ enum dma_data_direction direction)
+{
+ struct restricted_heap_attachment *a = attachment->priv;
+ struct sg_table *table = a->table;
+ int ret;
+
+ ret = dma_map_sgtable(attachment->dev, table, direction, DMA_ATTR_SKIP_CPU_SYNC);
+ if (ret)
+ return ERR_PTR(ret);
+ return table;
+}
+
+static void
+restricted_heap_unmap_dma_buf(struct dma_buf_attachment *attachment, struct sg_table *table,
+ enum dma_data_direction direction)
+{
+ struct restricted_heap_attachment *a = attachment->priv;
+
+ WARN_ON(a->table != table);
+
+ dma_unmap_sgtable(attachment->dev, table, direction, DMA_ATTR_SKIP_CPU_SYNC);
+}
+
+static int
+restricted_heap_dma_buf_begin_cpu_access(struct dma_buf *dmabuf, enum dma_data_direction direction)
+{
+ return -EPERM;
+}
+
+static int
+restricted_heap_dma_buf_end_cpu_access(struct dma_buf *dmabuf, enum dma_data_direction direction)
+{
+ return -EPERM;
+}
+
+static int restricted_heap_dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
+{
+ return -EPERM;
+}
+
+static void restricted_heap_free(struct dma_buf *dmabuf)
+{
+ struct restricted_buffer *restricted_buf = dmabuf->priv;
+ struct restricted_heap *rheap = dma_heap_get_drvdata(restricted_buf->heap);
+
+ restricted_heap_memory_free(rheap, restricted_buf);
+ kfree(restricted_buf);
+}
+
+static const struct dma_buf_ops restricted_heap_buf_ops = {
+ .attach = restricted_heap_attach,
+ .detach = restricted_heap_detach,
+ .map_dma_buf = restricted_heap_map_dma_buf,
+ .unmap_dma_buf = restricted_heap_unmap_dma_buf,
+ .begin_cpu_access = restricted_heap_dma_buf_begin_cpu_access,
+ .end_cpu_access = restricted_heap_dma_buf_end_cpu_access,
+ .mmap = restricted_heap_dma_buf_mmap,
+ .release = restricted_heap_free,
+};
+
static struct dma_buf *
restricted_heap_allocate(struct dma_heap *heap, unsigned long size,
unsigned long fd_flags, unsigned long heap_flags)
@@ -66,6 +167,7 @@ restricted_heap_allocate(struct dma_heap *heap, unsigned long size,
if (ret)
goto err_free_buf;
exp_info.exp_name = dma_heap_get_name(heap);
+ exp_info.ops = &restricted_heap_buf_ops;
exp_info.size = restricted_buf->size;
exp_info.flags = fd_flags;
exp_info.priv = restricted_buf;
diff --git a/drivers/dma-buf/heaps/restricted_heap.h b/drivers/dma-buf/heaps/restricted_heap.h
index 5783275d5714..6d9599a4a34e 100644
--- a/drivers/dma-buf/heaps/restricted_heap.h
+++ b/drivers/dma-buf/heaps/restricted_heap.h
@@ -11,6 +11,8 @@
struct restricted_buffer {
struct dma_heap *heap;
size_t size;
+
+ struct sg_table sg_table;
};
struct restricted_heap {
--
2.25.1