[PATCH v3 5/7] dma-buf: heaps: secure_heap: Add MediaTek secure heap and heap_init

Yong Wu
2023-12-12T02:47:33Z

Add a Mediatek secure heap which uses TEE service call to protect
buffer. Currently this secure heap is NULL, Prepare for the later patch.
Mainly there are two changes:
a) Add a heap_init ops since TEE probe late than secure heap, thus
initialize the heap when we require the buffer the first time.
b) Add a priv_data for each heap, like the special data used by MTK
(such as "TEE session") can be placed in priv_data.

Currently our heap depends on CMA which could only be bool, thus
depend on "TEE=y".

Signed-off-by: Yong Wu <yong.wu@mediatek.com>
---
drivers/dma-buf/heaps/Kconfig | 7 ++
drivers/dma-buf/heaps/Makefile | 1 +
drivers/dma-buf/heaps/secure_heap.c | 11 +++
drivers/dma-buf/heaps/secure_heap.h | 4 +
drivers/dma-buf/heaps/secure_heap_mtk.c | 114 ++++++++++++++++++++++++
5 files changed, 137 insertions(+)
create mode 100644 drivers/dma-buf/heaps/secure_heap_mtk.c

diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig
index 3a9943e94200..12962189878e 100644
--- a/drivers/dma-buf/heaps/Kconfig
+++ b/drivers/dma-buf/heaps/Kconfig
@@ -18,3 +18,10 @@ config DMABUF_HEAPS_SECURE
depends on DMABUF_HEAPS
help
Choose this option to enable dma-buf secure heap. If in doubt, say N.
+
+config DMABUF_HEAPS_SECURE_MTK
+ bool "MediaTek DMA-BUF Secure Heap"
+ depends on DMABUF_HEAPS_SECURE && TEE=y
+ help
+ Enable secure dma-buf heaps for MediaTek platform. This heap is backed by
+ TEE client interfaces. If in doubt, say N.
diff --git a/drivers/dma-buf/heaps/Makefile b/drivers/dma-buf/heaps/Makefile
index b1ad9d1f2fbe..9751dea345df 100644
--- a/drivers/dma-buf/heaps/Makefile
+++ b/drivers/dma-buf/heaps/Makefile
@@ -1,4 +1,5 @@
# SPDX-License-Identifier: GPL-2.0
obj-$(CONFIG_DMABUF_HEAPS_SECURE) += secure_heap.o
+obj-$(CONFIG_DMABUF_HEAPS_SECURE_MTK) += secure_heap_mtk.o
obj-$(CONFIG_DMABUF_HEAPS_SYSTEM) += system_heap.o
obj-$(CONFIG_DMABUF_HEAPS_CMA) += cma_heap.o
diff --git a/drivers/dma-buf/heaps/secure_heap.c b/drivers/dma-buf/heaps/secure_heap.c
index 7cb4db3e55c2..ca4b433fb3f1 100644
--- a/drivers/dma-buf/heaps/secure_heap.c
+++ b/drivers/dma-buf/heaps/secure_heap.c
@@ -150,11 +150,22 @@ 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);
+ const struct secure_heap_ops *ops = sec_heap->ops;
struct secure_buffer *sec_buf;
DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
struct dma_buf *dmabuf;
int ret;

+ /*
+ * In some implements, TEE is required to protect buffer. However TEE probe
+ * may be late, Thus heap_init is performed when the first buffer is requested.
+ */
+ if (ops->heap_init) {
+ ret = ops->heap_init(sec_heap);
+ if (ret)
+ return ERR_PTR(ret);
+ }
+
sec_buf = kzalloc(sizeof(*sec_buf), GFP_KERNEL);
if (!sec_buf)
return ERR_PTR(-ENOMEM);
diff --git a/drivers/dma-buf/heaps/secure_heap.h b/drivers/dma-buf/heaps/secure_heap.h
index ec5349cd28d0..1ce9c431d989 100644
--- a/drivers/dma-buf/heaps/secure_heap.h
+++ b/drivers/dma-buf/heaps/secure_heap.h
@@ -17,9 +17,13 @@ struct secure_heap {
const char *name;

const struct secure_heap_ops *ops;
+
+ void *priv_data;
};

struct secure_heap_ops {
+ int (*heap_init)(struct secure_heap *sec_heap);
+
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);

diff --git a/drivers/dma-buf/heaps/secure_heap_mtk.c b/drivers/dma-buf/heaps/secure_heap_mtk.c
new file mode 100644
index 000000000000..c7e609dd7bd3
--- /dev/null
+++ b/drivers/dma-buf/heaps/secure_heap_mtk.c
@@ -0,0 +1,114 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DMABUF MediaTek secure heap exporter
+ *
+ * Copyright (C) 2023 MediaTek Inc.
+ */
+#include <linux/dma-buf.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/tee_drv.h>
+#include <linux/uuid.h>
+
+#include "secure_heap.h"
+
+#define TZ_TA_MEM_UUID_MTK "4477588a-8476-11e2-ad15-e41f1390d676"
+
+#define TEE_PARAM_NUM 4
+
+enum mtk_secure_mem_type {
+ /*
+ * MediaTek static chunk memory carved out for TrustZone. The memory
+ * management is inside the TEE.
+ */
+ MTK_SECURE_MEMORY_TYPE_CM_TZ = 1,
+};
+
+struct mtk_secure_heap_data {
+ struct tee_context *tee_ctx;
+ u32 tee_session;
+
+ const enum mtk_secure_mem_type mem_type;
+
+};
+
+static int mtk_tee_ctx_match(struct tee_ioctl_version_data *ver, const void *data)
+{
+ return ver->impl_id == TEE_IMPL_ID_OPTEE;
+}
+
+static int mtk_tee_session_init(struct mtk_secure_heap_data *data)
+{
+ struct tee_param t_param[TEE_PARAM_NUM] = {0};
+ struct tee_ioctl_open_session_arg arg = {0};
+ uuid_t ta_mem_uuid;
+ int ret;
+
+ data->tee_ctx = tee_client_open_context(NULL, mtk_tee_ctx_match, NULL, NULL);
+ if (IS_ERR(data->tee_ctx)) {
+ pr_err_once("%s: open context failed, ret=%ld\n", __func__,
+ PTR_ERR(data->tee_ctx));
+ return -ENODEV;
+ }
+
+ arg.num_params = TEE_PARAM_NUM;
+ arg.clnt_login = TEE_IOCTL_LOGIN_PUBLIC;
+ ret = uuid_parse(TZ_TA_MEM_UUID_MTK, &ta_mem_uuid);
+ if (ret)
+ goto close_context;
+ memcpy(&arg.uuid, &ta_mem_uuid.b, sizeof(ta_mem_uuid));
+
+ ret = tee_client_open_session(data->tee_ctx, &arg, t_param);
+ if (ret < 0 || arg.ret) {
+ pr_err_once("%s: open session failed, ret=%d:%d\n",
+ __func__, ret, arg.ret);
+ ret = -EINVAL;
+ goto close_context;
+ }
+ data->tee_session = arg.session;
+ return 0;
+
+close_context:
+ tee_client_close_context(data->tee_ctx);
+ return ret;
+}
+
+static int mtk_secure_heap_init(struct secure_heap *sec_heap)
+{
+ struct mtk_secure_heap_data *data = sec_heap->priv_data;
+
+ if (!data->tee_ctx)
+ return mtk_tee_session_init(data);
+ return 0;
+}
+
+static const struct secure_heap_ops mtk_sec_mem_ops = {
+ .heap_init = mtk_secure_heap_init,
+};
+
+static struct mtk_secure_heap_data mtk_sec_heap_data = {
+ .mem_type = MTK_SECURE_MEMORY_TYPE_CM_TZ,
+};
+
+static struct secure_heap mtk_secure_heaps[] = {
+ {
+ .name = "secure_mtk_cm",
+ .ops = &mtk_sec_mem_ops,
+ .priv_data = &mtk_sec_heap_data,
+ },
+};
+
+static int mtk_sec_heap_init(void)
+{
+ struct secure_heap *sec_heap = mtk_secure_heaps;
+ unsigned int i;
+
+ for (i = 0; i < ARRAY_SIZE(mtk_secure_heaps); i++, sec_heap++)
+ secure_heap_add(sec_heap);
+ return 0;
+}
+
+module_init(mtk_sec_heap_init);
+MODULE_DESCRIPTION("MediaTek Secure Heap Driver");
+MODULE_LICENSE("GPL");
--
2.25.1