[PATCH v2 2/8] dma-buf: heaps: secure_heap: Add private heap ops

Yong Wu
2023-11-11T11:16:51Z

For the secure memory, there are two steps:
a) Allocate buffers in kernel side;
b) Secure that buffer.
Different heaps may have different buffer allocation methods and
different memory protection methods. Here abstract the memory
allocation and securing operations.

Signed-off-by: Yong Wu <yong.wu@mediatek.com>
---
drivers/dma-buf/heaps/secure_heap.c | 58 ++++++++++++++++++++++++++++-
1 file changed, 57 insertions(+), 1 deletion(-)

diff --git a/drivers/dma-buf/heaps/secure_heap.c b/drivers/dma-buf/heaps/secure_heap.c
index a634051a0a67..87ac23072e9e 100644
--- a/drivers/dma-buf/heaps/secure_heap.c
+++ b/drivers/dma-buf/heaps/secure_heap.c
@@ -24,15 +24,66 @@ struct secure_buffer {
size_t size;
};

+struct secure_heap;
+
+struct secure_heap_prv_data {
+ int (*memory_alloc)(struct secure_heap *sec_heap, struct secure_buffer *sec_buf);
+ void (*memory_free)(struct secure_heap *sec_heap, struct secure_buffer *sec_buf);
+
+ /* Protect/unprotect the memory */
+ int (*secure_the_memory)(struct secure_heap *sec_heap, struct secure_buffer *sec_buf);
+ void (*unsecure_the_memory)(struct secure_heap *sec_heap, struct secure_buffer *sec_buf);
+};
+
struct secure_heap {
const char *name;
const enum secure_memory_type mem_type;
+
+ const struct secure_heap_prv_data *data;
};

+static int secure_heap_secure_memory_allocate(struct secure_heap *sec_heap,
+ struct secure_buffer *sec_buf)
+{
+ const struct secure_heap_prv_data *data = sec_heap->data;
+ int ret;
+
+ if (data->memory_alloc) {
+ ret = data->memory_alloc(sec_heap, sec_buf);
+ if (ret)
+ return ret;
+ }
+
+ if (data->secure_the_memory) {
+ ret = data->secure_the_memory(sec_heap, sec_buf);
+ if (ret)
+ goto sec_memory_free;
+ }
+ return 0;
+
+sec_memory_free:
+ if (data->memory_free)
+ data->memory_free(sec_heap, sec_buf);
+ return ret;
+}
+
+static void secure_heap_secure_memory_free(struct secure_heap *sec_heap,
+ struct secure_buffer *sec_buf)
+{
+ const struct secure_heap_prv_data *data = sec_heap->data;
+
+ if (data->unsecure_the_memory)
+ data->unsecure_the_memory(sec_heap, sec_buf);
+
+ if (data->memory_free)
+ data->memory_free(sec_heap, sec_buf);
+}
+
static struct dma_buf *
secure_heap_allocate(struct dma_heap *heap, unsigned long size,
unsigned long fd_flags, unsigned long heap_flags)
{
+ struct secure_heap *sec_heap = dma_heap_get_drvdata(heap);
struct secure_buffer *sec_buf;
DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
struct dma_buf *dmabuf;
@@ -45,6 +96,9 @@ secure_heap_allocate(struct dma_heap *heap, unsigned long size,
sec_buf->size = ALIGN(size, PAGE_SIZE);
sec_buf->heap = heap;

+ ret = secure_heap_secure_memory_allocate(sec_heap, sec_buf);
+ if (ret)
+ goto err_free_buf;
exp_info.exp_name = dma_heap_get_name(heap);
exp_info.size = sec_buf->size;
exp_info.flags = fd_flags;
@@ -53,11 +107,13 @@ secure_heap_allocate(struct dma_heap *heap, unsigned long size,
dmabuf = dma_buf_export(&exp_info);
if (IS_ERR(dmabuf)) {
ret = PTR_ERR(dmabuf);
- goto err_free_buf;
+ goto err_free_sec_mem;
}

return dmabuf;

+err_free_sec_mem:
+ secure_heap_secure_memory_free(sec_heap, sec_buf);
err_free_buf:
kfree(sec_buf);
return ERR_PTR(ret);
--
2.25.1