Add restricted memory allocation to the TEE subsystem. Restricted memory is not be accessible by kernel during normal circumstances. A new ioctl TEE_IOC_RSTMEM_ALLOC is added to allocate these restricted memory buffers. The restricted memory is supposed to we used in special use-cases like Secure Data Path or Trusted UI where certain hardware devices can access the memory.
Signed-off-by: Jens Wiklander jens.wiklander@linaro.org --- drivers/tee/Makefile | 1 + drivers/tee/tee_core.c | 33 +++++- drivers/tee/tee_private.h | 2 + drivers/tee/tee_rstmem.c | 200 +++++++++++++++++++++++++++++++++++++ drivers/tee/tee_shm.c | 2 + drivers/tee/tee_shm_pool.c | 69 ++++++++++++- include/linux/tee_core.h | 6 ++ include/linux/tee_drv.h | 9 ++ include/uapi/linux/tee.h | 33 +++++- 9 files changed, 351 insertions(+), 4 deletions(-) create mode 100644 drivers/tee/tee_rstmem.c
diff --git a/drivers/tee/Makefile b/drivers/tee/Makefile index 5488cba30bd2..a4c6b55444b9 100644 --- a/drivers/tee/Makefile +++ b/drivers/tee/Makefile @@ -3,6 +3,7 @@ obj-$(CONFIG_TEE) += tee.o tee-objs += tee_core.o tee-objs += tee_shm.o tee-objs += tee_shm_pool.o +tee-objs += tee_rstmem.o obj-$(CONFIG_OPTEE) += optee/ obj-$(CONFIG_AMDTEE) += amdtee/ obj-$(CONFIG_ARM_TSTEE) += tstee/ diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c index d52e879b204e..0f4eee05ab13 100644 --- a/drivers/tee/tee_core.c +++ b/drivers/tee/tee_core.c @@ -1,12 +1,13 @@ // SPDX-License-Identifier: GPL-2.0-only /* - * Copyright (c) 2015-2016, Linaro Limited + * Copyright (c) 2015-2022, 2024, Linaro Limited */
#define pr_fmt(fmt) "%s: " fmt, __func__
#include <linux/cdev.h> #include <linux/cred.h> +#include <linux/dma-buf.h> #include <linux/fs.h> #include <linux/idr.h> #include <linux/module.h> @@ -818,6 +819,34 @@ static int tee_ioctl_supp_send(struct tee_context *ctx, return rc; }
+static int +tee_ioctl_rstmem_alloc(struct tee_context *ctx, + struct tee_ioctl_rstmem_alloc_data __user *udata) +{ + struct tee_ioctl_rstmem_alloc_data data; + struct dma_buf *dmabuf; + int id; + int fd; + + if (copy_from_user(&data, udata, sizeof(data))) + return -EFAULT; + + dmabuf = tee_rstmem_alloc(ctx, data.flags, data.size, &id); + if (IS_ERR(dmabuf)) + return PTR_ERR(dmabuf); + if (put_user(id, &udata->id)) { + fd = -EFAULT; + goto err; + } + fd = dma_buf_fd(dmabuf, O_CLOEXEC); + if (fd < 0) + goto err; + return fd; +err: + dma_buf_put(dmabuf); + return fd; +} + static long tee_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) { struct tee_context *ctx = filp->private_data; @@ -842,6 +871,8 @@ static long tee_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) return tee_ioctl_supp_recv(ctx, uarg); case TEE_IOC_SUPPL_SEND: return tee_ioctl_supp_send(ctx, uarg); + case TEE_IOC_RSTMEM_ALLOC: + return tee_ioctl_rstmem_alloc(ctx, uarg); default: return -EINVAL; } diff --git a/drivers/tee/tee_private.h b/drivers/tee/tee_private.h index 9bc50605227c..8eccbb4ce5f7 100644 --- a/drivers/tee/tee_private.h +++ b/drivers/tee/tee_private.h @@ -23,5 +23,7 @@ void teedev_ctx_put(struct tee_context *ctx); struct tee_shm *tee_shm_alloc_user_buf(struct tee_context *ctx, size_t size); struct tee_shm *tee_shm_register_user_buf(struct tee_context *ctx, unsigned long addr, size_t length); +struct dma_buf *tee_rstmem_alloc(struct tee_context *ctx, u32 flags, + size_t size, int *shm_id);
#endif /*TEE_PRIVATE_H*/ diff --git a/drivers/tee/tee_rstmem.c b/drivers/tee/tee_rstmem.c new file mode 100644 index 000000000000..948c8e8fe96c --- /dev/null +++ b/drivers/tee/tee_rstmem.c @@ -0,0 +1,200 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2024 Linaro Limited + */ +#include <linux/device.h> +#include <linux/dma-buf.h> +#include <linux/genalloc.h> +#include <linux/scatterlist.h> +#include <linux/slab.h> +#include <linux/tee_core.h> +#include "tee_private.h" + +struct tee_rstmem_attachment { + struct sg_table table; + struct device *dev; +}; + +static int rstmem_dma_attach(struct dma_buf *dmabuf, + struct dma_buf_attachment *attachment) +{ + struct tee_shm *shm = dmabuf->priv; + struct tee_rstmem_attachment *a; + int rc; + + a = kzalloc(sizeof(*a), GFP_KERNEL); + if (!a) + return -ENOMEM; + + if (shm->pages) { + rc = sg_alloc_table_from_pages(&a->table, shm->pages, + shm->num_pages, 0, + shm->num_pages * PAGE_SIZE, + GFP_KERNEL); + if (rc) + goto err; + } else { + rc = sg_alloc_table(&a->table, 1, GFP_KERNEL); + if (rc) + goto err; + sg_set_page(a->table.sgl, phys_to_page(shm->paddr), shm->size, + 0); + } + + a->dev = attachment->dev; + attachment->priv = a; + + return 0; +err: + kfree(a); + return rc; +} + +static void rstmem_dma_detach(struct dma_buf *dmabuf, + struct dma_buf_attachment *attachment) +{ + struct tee_rstmem_attachment *a = attachment->priv; + + sg_free_table(&a->table); + kfree(a); +} + +static struct sg_table * +rstmem_dma_map_dma_buf(struct dma_buf_attachment *attachment, + enum dma_data_direction direction) +{ + struct tee_rstmem_attachment *a = attachment->priv; + int ret; + + ret = dma_map_sgtable(attachment->dev, &a->table, direction, + DMA_ATTR_SKIP_CPU_SYNC); + if (ret) + return ERR_PTR(ret); + + return &a->table; +} + +static void rstmem_dma_unmap_dma_buf(struct dma_buf_attachment *attachment, + struct sg_table *table, + enum dma_data_direction direction) +{ + struct tee_rstmem_attachment *a = attachment->priv; + + WARN_ON(&a->table != table); + + dma_unmap_sgtable(attachment->dev, table, direction, + DMA_ATTR_SKIP_CPU_SYNC); +} + +static int rstmem_dma_buf_begin_cpu_access(struct dma_buf *dmabuf, + enum dma_data_direction direction) +{ + return -EPERM; +} + +static int rstmem_dma_buf_end_cpu_access(struct dma_buf *dmabuf, + enum dma_data_direction direction) +{ + return -EPERM; +} + +static int rstmem_dma_buf_mmap(struct dma_buf *dmabuf, + struct vm_area_struct *vma) +{ + return -EPERM; +} + +static void rstmem_dma_buf_free(struct dma_buf *dmabuf) +{ + struct tee_shm *shm = dmabuf->priv; + + tee_shm_put(shm); +} + +static const struct dma_buf_ops rstmem_generic_buf_ops = { + .attach = rstmem_dma_attach, + .detach = rstmem_dma_detach, + .map_dma_buf = rstmem_dma_map_dma_buf, + .unmap_dma_buf = rstmem_dma_unmap_dma_buf, + .begin_cpu_access = rstmem_dma_buf_begin_cpu_access, + .end_cpu_access = rstmem_dma_buf_end_cpu_access, + .mmap = rstmem_dma_buf_mmap, + .release = rstmem_dma_buf_free, +}; + +struct dma_buf *tee_rstmem_alloc(struct tee_context *ctx, u32 flags, + size_t size, int *shm_id) +{ + struct tee_device *teedev = ctx->teedev; + DEFINE_DMA_BUF_EXPORT_INFO(exp_info); + struct dma_buf *dmabuf; + struct tee_shm *shm; + void *ret; + int rc; + + if (!tee_device_get(teedev)) + return ERR_PTR(-EINVAL); + + if (!teedev->desc->ops->rstmem_alloc || + !teedev->desc->ops->rstmem_free) { + dmabuf = ERR_PTR(-EINVAL); + goto err; + } + + shm = kzalloc(sizeof(*shm), GFP_KERNEL); + if (!shm) { + dmabuf = ERR_PTR(-ENOMEM); + goto err; + } + + refcount_set(&shm->refcount, 1); + shm->flags = TEE_SHM_RESTRICTED; + shm->ctx = ctx; + + mutex_lock(&teedev->mutex); + shm->id = idr_alloc(&teedev->idr, NULL, 1, 0, GFP_KERNEL); + mutex_unlock(&teedev->mutex); + if (shm->id < 0) { + dmabuf = ERR_PTR(shm->id); + goto err_kfree; + } + + rc = teedev->desc->ops->rstmem_alloc(ctx, shm, flags, size); + if (rc) { + dmabuf = ERR_PTR(rc); + goto err_idr_remove; + } + + mutex_lock(&teedev->mutex); + ret = idr_replace(&teedev->idr, shm, shm->id); + mutex_unlock(&teedev->mutex); + if (IS_ERR(ret)) { + dmabuf = ret; + goto err_rstmem_free; + } + teedev_ctx_get(ctx); + + exp_info.ops = &rstmem_generic_buf_ops; + exp_info.size = shm->size; + exp_info.priv = shm; + dmabuf = dma_buf_export(&exp_info); + if (IS_ERR(dmabuf)) { + tee_shm_put(shm); + return dmabuf; + } + + *shm_id = shm->id; + return dmabuf; + +err_rstmem_free: + teedev->desc->ops->rstmem_free(ctx, shm); +err_idr_remove: + mutex_lock(&teedev->mutex); + idr_remove(&teedev->idr, shm->id); + mutex_unlock(&teedev->mutex); +err_kfree: + kfree(shm); +err: + tee_device_put(teedev); + return dmabuf; +} diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c index daf6e5cfd59a..416f7f25d885 100644 --- a/drivers/tee/tee_shm.c +++ b/drivers/tee/tee_shm.c @@ -55,6 +55,8 @@ static void tee_shm_release(struct tee_device *teedev, struct tee_shm *shm) "unregister shm %p failed: %d", shm, rc);
release_registered_pages(shm); + } else if (shm->flags & TEE_SHM_RESTRICTED) { + teedev->desc->ops->rstmem_free(shm->ctx, shm); }
teedev_ctx_put(shm->ctx); diff --git a/drivers/tee/tee_shm_pool.c b/drivers/tee/tee_shm_pool.c index 80004b55628d..ee57ef157a77 100644 --- a/drivers/tee/tee_shm_pool.c +++ b/drivers/tee/tee_shm_pool.c @@ -1,9 +1,8 @@ // SPDX-License-Identifier: GPL-2.0-only /* - * Copyright (c) 2015, 2017, 2022 Linaro Limited + * Copyright (c) 2015, 2017, 2022, 2024 Linaro Limited */ #include <linux/device.h> -#include <linux/dma-buf.h> #include <linux/genalloc.h> #include <linux/slab.h> #include <linux/tee_core.h> @@ -90,3 +89,69 @@ struct tee_shm_pool *tee_shm_pool_alloc_res_mem(unsigned long vaddr, return ERR_PTR(rc); } EXPORT_SYMBOL_GPL(tee_shm_pool_alloc_res_mem); + +static int rstmem_pool_op_gen_alloc(struct tee_shm_pool *pool, + struct tee_shm *shm, size_t size, + size_t align) +{ + size_t sz = ALIGN(size, PAGE_SIZE); + phys_addr_t pa; + + pa = gen_pool_alloc(pool->private_data, sz); + if (!pa) + return -ENOMEM; + + shm->size = sz; + shm->paddr = pa; + + return 0; +} + +static void rstmem_pool_op_gen_free(struct tee_shm_pool *pool, + struct tee_shm *shm) +{ + gen_pool_free(pool->private_data, shm->paddr, shm->size); + shm->paddr = 0; +} + +static struct tee_shm_pool_ops rstmem_pool_ops_generic = { + .alloc = rstmem_pool_op_gen_alloc, + .free = rstmem_pool_op_gen_free, + .destroy_pool = pool_op_gen_destroy_pool, +}; + +struct tee_shm_pool *tee_rstmem_gen_pool_alloc(phys_addr_t paddr, size_t size) +{ + const size_t page_mask = PAGE_SIZE - 1; + struct tee_shm_pool *pool; + int rc; + + /* Check it's page aligned */ + if ((paddr | size) & page_mask) + return ERR_PTR(-EINVAL); + + pool = kzalloc(sizeof(*pool), GFP_KERNEL); + if (!pool) + return ERR_PTR(-ENOMEM); + + pool->private_data = gen_pool_create(PAGE_SHIFT, -1); + if (!pool->private_data) { + rc = -ENOMEM; + goto err_free; + } + + rc = gen_pool_add(pool->private_data, paddr, size, -1); + if (rc) + goto err_free_pool; + + pool->ops = &rstmem_pool_ops_generic; + return pool; + +err_free_pool: + gen_pool_destroy(pool->private_data); +err_free: + kfree(pool); + + return ERR_PTR(rc); +} +EXPORT_SYMBOL_GPL(tee_rstmem_gen_pool_alloc); diff --git a/include/linux/tee_core.h b/include/linux/tee_core.h index efd16ed52315..8ffecddbbc4b 100644 --- a/include/linux/tee_core.h +++ b/include/linux/tee_core.h @@ -26,6 +26,7 @@ #define TEE_SHM_USER_MAPPED BIT(1) /* Memory mapped in user space */ #define TEE_SHM_POOL BIT(2) /* Memory allocated from pool */ #define TEE_SHM_PRIV BIT(3) /* Memory private to TEE driver */ +#define TEE_SHM_RESTRICTED BIT(4) /* Restricted memory */
#define TEE_DEVICE_FLAG_REGISTERED 0x1 #define TEE_MAX_DEV_NAME_LEN 32 @@ -76,6 +77,8 @@ struct tee_device { * @supp_send: called for supplicant to send a response * @shm_register: register shared memory buffer in TEE * @shm_unregister: unregister shared memory buffer in TEE + * @rstmem_alloc: allocate restricted memory + * @rstmem_free: free restricted memory */ struct tee_driver_ops { void (*get_version)(struct tee_device *teedev, @@ -99,6 +102,9 @@ struct tee_driver_ops { struct page **pages, size_t num_pages, unsigned long start); int (*shm_unregister)(struct tee_context *ctx, struct tee_shm *shm); + int (*rstmem_alloc)(struct tee_context *ctx, struct tee_shm *shm, + u32 flags, size_t size); + void (*rstmem_free)(struct tee_context *ctx, struct tee_shm *shm); };
/** diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h index a54c203000ed..71f40f2dbd98 100644 --- a/include/linux/tee_drv.h +++ b/include/linux/tee_drv.h @@ -174,6 +174,15 @@ static inline size_t tee_shm_get_page_offset(struct tee_shm *shm) return shm->offset; }
+/** + * tee_rstmem_gen_pool_alloc() - Create a restricted memory manager + * @paddr: Physical address of start of pool + * @size: Size in bytes of the pool + * + * @returns pointer to a 'struct tee_shm_pool' or an ERR_PTR on failure. + */ +struct tee_shm_pool *tee_rstmem_gen_pool_alloc(phys_addr_t paddr, size_t size); + /** * tee_client_open_context() - Open a TEE context * @start: if not NULL, continue search after this context diff --git a/include/uapi/linux/tee.h b/include/uapi/linux/tee.h index d0430bee8292..c023d7cdbe49 100644 --- a/include/uapi/linux/tee.h +++ b/include/uapi/linux/tee.h @@ -1,5 +1,5 @@ /* - * Copyright (c) 2015-2016, Linaro Limited + * Copyright (c) 2015-2017, 2020, 2024, Linaro Limited * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -48,6 +48,7 @@ #define TEE_GEN_CAP_PRIVILEGED (1 << 1)/* Privileged device (for supplicant) */ #define TEE_GEN_CAP_REG_MEM (1 << 2)/* Supports registering shared memory */ #define TEE_GEN_CAP_MEMREF_NULL (1 << 3)/* NULL MemRef support */ +#define TEE_GEN_CAP_RSTMEM (1 << 4)/* Supports restricted memory */
#define TEE_MEMREF_NULL (__u64)(-1) /* NULL MemRef Buffer */
@@ -389,6 +390,36 @@ struct tee_ioctl_shm_register_data { */ #define TEE_IOC_SHM_REGISTER _IOWR(TEE_IOC_MAGIC, TEE_IOC_BASE + 9, \ struct tee_ioctl_shm_register_data) + +#define TEE_IOC_FLAG_SECURE_VIDEO (1 << 0) +#define TEE_IOC_FLAG_TRUSTED_UI (1 << 1) + +/** + * struct tee_ioctl_rstmem_alloc_data - Restricted memory allocate argument + * @size: [in/out] Size of restricted memory to allocate + * @flags: [in/out] Flags to/from allocate + * @id: [out] Identifier of the restricted memory + */ +struct tee_ioctl_rstmem_alloc_data { + __u64 size; + __u32 flags; + __s32 id; +}; + +/** + * TEE_IOC_RSTMEM_ALLOC - allocate restricted memory + * + * Allocates restricted physically memory normally not accessible by the + * kernel. + * + * Returns a file descriptor on success or < 0 on failure + * + * The returned file descriptor is a dma-buf that can be attached and + * mapped for device with permission to access the physical memory. + */ +#define TEE_IOC_RSTMEM_ALLOC _IOWR(TEE_IOC_MAGIC, TEE_IOC_BASE + 10, \ + struct tee_ioctl_rstmem_alloc_data) + /* * Five syscalls are used when communicating with the TEE driver. * open(): opens the device associated with the driver