[PATCH v6 07/10] tee: add tee_shm_alloc_cma_phys_mem()

Jens Wiklander
2025-03-05T13:07:00Z

Add tee_shm_alloc_cma_phys_mem() to allocate a physical memory using
from the default CMA pool. The memory is represented by a tee_shm object
using the new flag TEE_SHM_CMA_BUF to identify it as physical memory
from CMA.

Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
---
drivers/tee/tee_shm.c | 55 ++++++++++++++++++++++++++++++++++++++--
include/linux/tee_core.h | 4 +++
2 files changed, 57 insertions(+), 2 deletions(-)

diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
index 8b79918468b5..8d8341f8ebd7 100644
--- a/drivers/tee/tee_shm.c
+++ b/drivers/tee/tee_shm.c
@@ -3,8 +3,11 @@
* Copyright (c) 2015-2017, 2019-2021 Linaro Limited
*/
#include <linux/anon_inodes.h>
+#include <linux/cma.h>
#include <linux/device.h>
#include <linux/dma-buf.h>
+#include <linux/dma-map-ops.h>
+#include <linux/highmem.h>
#include <linux/idr.h>
#include <linux/io.h>
#include <linux/mm.h>
@@ -13,7 +16,6 @@
#include <linux/tee_core.h>
#include <linux/uaccess.h>
#include <linux/uio.h>
-#include <linux/highmem.h>
#include "tee_private.h"

/* extra references appended to shm object for registered shared memory */
@@ -59,7 +61,14 @@ static void tee_shm_release(struct tee_device *teedev, struct tee_shm *shm)
struct tee_shm *parent_shm = NULL;
void *p = shm;

- if (shm->flags & TEE_SHM_DMA_BUF) {
+ if (shm->flags & TEE_SHM_CMA_BUF) {
+#if !IS_MODULE(CONFIG_TEE) && IS_ENABLED(CONFIG_CMA)
+ struct page *page = phys_to_page(shm->paddr);
+ struct cma *cma = dev_get_cma_area(&shm->ctx->teedev->dev);
+
+ cma_release(cma, page, shm->size / PAGE_SIZE);
+#endif
+ } else if (shm->flags & TEE_SHM_DMA_BUF) {
struct tee_shm_dmabuf_ref *ref;

ref = container_of(shm, struct tee_shm_dmabuf_ref, shm);
@@ -341,6 +350,48 @@ struct tee_shm *tee_shm_alloc_priv_buf(struct tee_context *ctx, size_t size)
}
EXPORT_SYMBOL_GPL(tee_shm_alloc_priv_buf);

+struct tee_shm *tee_shm_alloc_cma_phys_mem(struct tee_context *ctx,
+ size_t page_count, size_t align)
+{
+#if !IS_MODULE(CONFIG_TEE) && IS_ENABLED(CONFIG_CMA)
+ struct tee_device *teedev = ctx->teedev;
+ struct cma *cma = dev_get_cma_area(&teedev->dev);
+ struct tee_shm *shm;
+ struct page *page;
+
+ if (!tee_device_get(teedev))
+ return ERR_PTR(-EINVAL);
+
+ page = cma_alloc(cma, page_count, align, true/*no_warn*/);
+ if (!page)
+ goto err_put_teedev;
+
+ shm = kzalloc(sizeof(*shm), GFP_KERNEL);
+ if (!shm)
+ goto err_cma_crelease;
+
+ refcount_set(&shm->refcount, 1);
+ shm->ctx = ctx;
+ shm->paddr = page_to_phys(page);
+ shm->size = page_count * PAGE_SIZE;
+ shm->flags = TEE_SHM_CMA_BUF;
+
+ teedev_ctx_get(ctx);
+
+ return shm;
+
+err_cma_crelease:
+ cma_release(cma, page, page_count);
+err_put_teedev:
+ tee_device_put(teedev);
+
+ return ERR_PTR(-ENOMEM);
+#else
+ return ERR_PTR(-EINVAL);
+#endif
+}
+EXPORT_SYMBOL_GPL(tee_shm_alloc_cma_phys_mem);
+
int tee_dyn_shm_alloc_helper(struct tee_shm *shm, size_t size, size_t align,
int (*shm_register)(struct tee_context *ctx,
struct tee_shm *shm,
diff --git a/include/linux/tee_core.h b/include/linux/tee_core.h
index 6bd833b6d0e1..b6727d9a3556 100644
--- a/include/linux/tee_core.h
+++ b/include/linux/tee_core.h
@@ -29,6 +29,7 @@
#define TEE_SHM_POOL BIT(2) /* Memory allocated from pool */
#define TEE_SHM_PRIV BIT(3) /* Memory private to TEE driver */
#define TEE_SHM_DMA_BUF BIT(4) /* Memory with dma-buf handle */
+#define TEE_SHM_CMA_BUF BIT(5) /* CMA allocated memory */

#define TEE_DEVICE_FLAG_REGISTERED 0x1
#define TEE_MAX_DEV_NAME_LEN 32
@@ -307,6 +308,9 @@ void *tee_get_drvdata(struct tee_device *teedev);
*/
struct tee_shm *tee_shm_alloc_priv_buf(struct tee_context *ctx, size_t size);

+struct tee_shm *tee_shm_alloc_cma_phys_mem(struct tee_context *ctx,
+ size_t page_count, size_t align);
+
int tee_dyn_shm_alloc_helper(struct tee_shm *shm, size_t size, size_t align,
int (*shm_register)(struct tee_context *ctx,
struct tee_shm *shm,
--
2.43.0