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tee: add tee_shm_alloc_dma_mem()

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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.

Reviewed-by: Sumit Garg <sumit.garg@oss.qualcomm.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
This commit is contained in:
Jens Wiklander 2025-08-13 08:02:55 +02:00
parent 146bf4e75e
commit ab09dd6d92
2 changed files with 88 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

85
drivers/tee/tee_shm.c
View file

@ -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;
@ -48,7 +55,16 @@ static void tee_shm_release(struct tee_device *teedev, struct tee_shm *shm)
{
void *p = shm;
if (shm->flags & TEE_SHM_DMA_BUF) {
if (shm->flags & TEE_SHM_DMA_MEM) {
#if IS_ENABLED(CONFIG_TEE_DMABUF_HEAPS)
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);
#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);
@ -268,6 +284,71 @@ struct tee_shm *tee_shm_alloc_priv_buf(struct tee_context *ctx, size_t size)
}
EXPORT_SYMBOL_GPL(tee_shm_alloc_priv_buf);
#if IS_ENABLED(CONFIG_TEE_DMABUF_HEAPS)
/**
* 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);
#else
struct tee_shm *tee_shm_alloc_dma_mem(struct tee_context *ctx,
size_t page_count)
{
return ERR_PTR(-EINVAL);
}
EXPORT_SYMBOL_GPL(tee_shm_alloc_dma_mem);
#endif
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,

5
include/linux/tee_core.h
View file

@ -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
@ -298,6 +300,9 @@ 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,