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

Sumit Garg
2025-03-25T06:53:54Z

Hi Jens,

On Wed, Mar 05, 2025 at 02:04:13PM +0100, Jens Wiklander wrote:
> 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)

Can we rather manage this dependency via Kconfig?

> + 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)

Ditto here.

-Sumit

> + 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
>