On Tue, May 20, 2025 at 05:16:49PM +0200, Jens Wiklander wrote:
> Add tee_shm_alloc_dma_mem() to allocate DMA memory. The memory is
> represented by a tee_shm object using the new flag TEE_SHM_DMA_MEM to
> identify it as DMA memory. The allocated memory will later be lent to
> the TEE to be used as protected memory.
>
> Signed-off-by: Jens Wiklander <jens.wiklan...@linaro.org>
> ---
> drivers/tee/tee_shm.c | 74 ++++++++++++++++++++++++++++++++++++++--
> include/linux/tee_core.h | 5 +++
> 2 files changed, 77 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
> index e1ed52ee0a16..92a6a35e1a1e 100644
> --- a/drivers/tee/tee_shm.c
> +++ b/drivers/tee/tee_shm.c
> @@ -5,6 +5,8 @@
> #include <linux/anon_inodes.h>
> #include <linux/device.h>
> #include <linux/dma-buf.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/highmem.h>
> #include <linux/idr.h>
> #include <linux/io.h>
> #include <linux/mm.h>
> @@ -13,9 +15,14 @@
> #include <linux/tee_core.h>
> #include <linux/uaccess.h>
> #include <linux/uio.h>
> -#include <linux/highmem.h>
> #include "tee_private.h"
>
> +struct tee_shm_dma_mem {
> + struct tee_shm shm;
> + dma_addr_t dma_addr;
> + struct page *page;
> +};
> +
> static void shm_put_kernel_pages(struct page **pages, size_t page_count)
> {
> size_t n;
> @@ -49,7 +56,14 @@ 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_DMA_MEM) {
> + struct tee_shm_dma_mem *dma_mem;
> +
> + dma_mem = container_of(shm, struct tee_shm_dma_mem, shm);
> + p = dma_mem;
> + dma_free_pages(&teedev->dev, shm->size, dma_mem->page,
> + dma_mem->dma_addr, DMA_BIDIRECTIONAL);
Although the kernel bot already found a randconfig issue, it looks like
we need to add Kconfig dependencies like HAS_DMA, DMA_CMA etc.
Also, I was thinking if we should rather add a new TEE subsystem
specific Kconfig option like: TEE_DMABUF_HEAPS which can then be used to
select whatever dependency is needed as well as act as a gating Kconfig
for relevant features.
-Sumit
> + } else if (shm->flags & TEE_SHM_DMA_BUF) {
> struct tee_shm_dmabuf_ref *ref;
>
> ref = container_of(shm, struct tee_shm_dmabuf_ref, shm);
> @@ -306,6 +320,62 @@ struct tee_shm *tee_shm_alloc_priv_buf(struct
> tee_context *ctx, size_t size)
> }
> EXPORT_SYMBOL_GPL(tee_shm_alloc_priv_buf);
>
> +/**
> + * tee_shm_alloc_dma_mem() - Allocate DMA memory as shared memory object
> + * @ctx: Context that allocates the shared memory
> + * @page_count: Number of pages
> + *
> + * The allocated memory is expected to be lent (made inaccessible to the
> + * kernel) to the TEE while it's used and returned (accessible to the
> + * kernel again) before it's freed.
> + *
> + * This function should normally only be used internally in the TEE
> + * drivers.
> + *
> + * @returns a pointer to 'struct tee_shm'
> + */
> +struct tee_shm *tee_shm_alloc_dma_mem(struct tee_context *ctx,
> + size_t page_count)
> +{
> + struct tee_device *teedev = ctx->teedev;
> + struct tee_shm_dma_mem *dma_mem;
> + dma_addr_t dma_addr;
> + struct page *page;
> +
> + if (!tee_device_get(teedev))
> + return ERR_PTR(-EINVAL);
> +
> + page = dma_alloc_pages(&teedev->dev, page_count * PAGE_SIZE,
> + &dma_addr, DMA_BIDIRECTIONAL, GFP_KERNEL);
> + if (!page)
> + goto err_put_teedev;
> +
> + dma_mem = kzalloc(sizeof(*dma_mem), GFP_KERNEL);
> + if (!dma_mem)
> + goto err_free_pages;
> +
> + refcount_set(&dma_mem->shm.refcount, 1);
> + dma_mem->shm.ctx = ctx;
> + dma_mem->shm.paddr = page_to_phys(page);
> + dma_mem->dma_addr = dma_addr;
> + dma_mem->page = page;
> + dma_mem->shm.size = page_count * PAGE_SIZE;
> + dma_mem->shm.flags = TEE_SHM_DMA_MEM;
> +
> + teedev_ctx_get(ctx);
> +
> + return &dma_mem->shm;
> +
> +err_free_pages:
> + dma_free_pages(&teedev->dev, page_count * PAGE_SIZE, page, dma_addr,
> + DMA_BIDIRECTIONAL);
> +err_put_teedev:
> + tee_device_put(teedev);
> +
> + return ERR_PTR(-ENOMEM);
> +}
> +EXPORT_SYMBOL_GPL(tee_shm_alloc_dma_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 02c07f661349..925690e1020b 100644
> --- a/include/linux/tee_core.h
> +++ b/include/linux/tee_core.h
> @@ -29,6 +29,8 @@
> #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_DMA_MEM BIT(5) /* Memory allocated with */
> + /* dma_alloc_pages() */
>
> #define TEE_DEVICE_FLAG_REGISTERED 0x1
> #define TEE_MAX_DEV_NAME_LEN 32
> @@ -310,6 +312,9 @@ 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_dma_mem(struct tee_context *ctx,
> + size_t page_count);
> +
> 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
>
