// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (c) 2015-2017, 2019-2021 Linaro Limited */ #include <linux/anon_inodes.h> #include <linux/device.h> #include <linux/idr.h> #include <linux/mm.h> #include <linux/sched.h> #include <linux/slab.h> #include <linux/tee_drv.h> #include <linux/uaccess.h> #include <linux/uio.h> #include "tee_private.h" static void shm_put_kernel_pages(struct page **pages, size_t page_count) { size_t n; for (n = 0; n < page_count; n++) put_page(pages[n]); } static int shm_get_kernel_pages(unsigned long start, size_t page_count, struct page **pages) { size_t n; int rc; if (is_vmalloc_addr((void *)start)) { struct page *page; for (n = 0; n < page_count; n++) { page = vmalloc_to_page((void *)(start + PAGE_SIZE * n)); if (!page) return -ENOMEM; get_page(page); pages[n] = page; } rc = page_count; } else { struct kvec *kiov; kiov = kcalloc(page_count, sizeof(*kiov), GFP_KERNEL); if (!kiov) return -ENOMEM; for (n = 0; n < page_count; n++) { kiov[n].iov_base = (void *)(start + n * PAGE_SIZE); kiov[n].iov_len = PAGE_SIZE; } rc = get_kernel_pages(kiov, page_count, 0, pages); kfree(kiov); } return rc; } static void release_registered_pages(struct tee_shm *shm) { if (shm->pages) { if (shm->flags & TEE_SHM_USER_MAPPED) unpin_user_pages(shm->pages, shm->num_pages); else shm_put_kernel_pages(shm->pages, shm->num_pages); kfree(shm->pages); } } static void tee_shm_release(struct tee_device *teedev, struct tee_shm *shm) { if (shm->flags & TEE_SHM_POOL) { teedev->pool->ops->free(teedev->pool, shm); } else if (shm->flags & TEE_SHM_DYNAMIC) { int rc = teedev->desc->ops->shm_unregister(shm->ctx, shm); if (rc) dev_err(teedev->dev.parent, "unregister shm %p failed: %d", shm, rc); release_registered_pages(shm); } teedev_ctx_put(shm->ctx); kfree(shm); tee_device_put(teedev); } static struct tee_shm *shm_alloc_helper(struct tee_context *ctx, size_t size, size_t align, u32 flags, int id) { struct tee_device *teedev = ctx->teedev; struct tee_shm *shm; void *ret; int rc; if (!tee_device_get(teedev)) return ERR_PTR(-EINVAL); if (!teedev->pool) { /* teedev has been detached from driver */ ret = ERR_PTR(-EINVAL); goto err_dev_put; } shm = kzalloc(sizeof(*shm), GFP_KERNEL); if (!shm) { ret = ERR_PTR(-ENOMEM); goto err_dev_put; } refcount_set(&shm->refcount, 1); shm->flags = flags; shm->id = id; /* * We're assigning this as it is needed if the shm is to be * registered. If this function returns OK then the caller expected * to call teedev_ctx_get() or clear shm->ctx in case it's not * needed any longer. */ shm->ctx = ctx; rc = teedev->pool->ops->alloc(teedev->pool, shm, size, align); if (rc) { ret = ERR_PTR(rc); goto err_kfree; } teedev_ctx_get(ctx); return shm; err_kfree: kfree(shm); err_dev_put: tee_device_put(teedev); return ret; } /** * tee_shm_alloc_user_buf() - Allocate shared memory for user space * @ctx: Context that allocates the shared memory * @size: Requested size of shared memory * * Memory allocated as user space shared memory is automatically freed when * the TEE file pointer is closed. The primary usage of this function is * when the TEE driver doesn't support registering ordinary user space * memory. * * @returns a pointer to 'struct tee_shm' */ struct tee_shm *tee_shm_alloc_user_buf(struct tee_context *ctx, size_t size) { u32 flags = TEE_SHM_DYNAMIC | TEE_SHM_POOL; struct tee_device *teedev = ctx->teedev; struct tee_shm *shm; void *ret; int id; mutex_lock(&teedev->mutex); id = idr_alloc(&teedev->idr, NULL, 1, 0, GFP_KERNEL); mutex_unlock(&teedev->mutex); if (id < 0) return ERR_PTR(id); shm = shm_alloc_helper(ctx, size, PAGE_SIZE, flags, id); if (IS_ERR(shm)) { mutex_lock(&teedev->mutex); idr_remove(&teedev->idr, id); mutex_unlock(&teedev->mutex); return shm; } mutex_lock(&teedev->mutex); ret = idr_replace(&teedev->idr, shm, id); mutex_unlock(&teedev->mutex); if (IS_ERR(ret)) { tee_shm_free(shm); return ret; } return shm; } /** * tee_shm_alloc_kernel_buf() - Allocate shared memory for kernel buffer * @ctx: Context that allocates the shared memory * @size: Requested size of shared memory * * The returned memory registered in secure world and is suitable to be * passed as a memory buffer in parameter argument to * tee_client_invoke_func(). The memory allocated is later freed with a * call to tee_shm_free(). * * @returns a pointer to 'struct tee_shm' */ struct tee_shm *tee_shm_alloc_kernel_buf(struct tee_context *ctx, size_t size) { u32 flags = TEE_SHM_DYNAMIC | TEE_SHM_POOL; return shm_alloc_helper(ctx, size, PAGE_SIZE, flags, -1); } EXPORT_SYMBOL_GPL(tee_shm_alloc_kernel_buf); /** * tee_shm_alloc_priv_buf() - Allocate shared memory for a privately shared * kernel buffer * @ctx: Context that allocates the shared memory * @size: Requested size of shared memory * * This function returns similar shared memory as * tee_shm_alloc_kernel_buf(), but with the difference that the memory * might not be registered in secure world in case the driver supports * passing memory not registered in advance. * * 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_priv_buf(struct tee_context *ctx, size_t size) { u32 flags = TEE_SHM_PRIV | TEE_SHM_POOL; return shm_alloc_helper(ctx, size, sizeof(long) * 2, flags, -1); } EXPORT_SYMBOL_GPL(tee_shm_alloc_priv_buf); static struct tee_shm * register_shm_helper(struct tee_context *ctx, unsigned long addr, size_t length, u32 flags, int id) { struct tee_device *teedev = ctx->teedev; struct tee_shm *shm; unsigned long start; size_t num_pages; void *ret; int rc; if (!tee_device_get(teedev)) return ERR_PTR(-EINVAL); if (!teedev->desc->ops->shm_register || !teedev->desc->ops->shm_unregister) { ret = ERR_PTR(-ENOTSUPP); goto err_dev_put; } teedev_ctx_get(ctx); shm = kzalloc(sizeof(*shm), GFP_KERNEL); if (!shm) { ret = ERR_PTR(-ENOMEM); goto err_ctx_put; } refcount_set(&shm->refcount, 1); shm->flags = flags; shm->ctx = ctx; shm->id = id; addr = untagged_addr(addr); start = rounddown(addr, PAGE_SIZE); shm->offset = addr - start; shm->size = length; num_pages = (roundup(addr + length, PAGE_SIZE) - start) / PAGE_SIZE; shm->pages = kcalloc(num_pages, sizeof(*shm->pages), GFP_KERNEL); if (!shm->pages) { ret = ERR_PTR(-ENOMEM); goto err_free_shm; } if (flags & TEE_SHM_USER_MAPPED) rc = pin_user_pages_fast(start, num_pages, FOLL_WRITE, shm->pages); else rc = shm_get_kernel_pages(start, num_pages, shm->pages); if (rc > 0) shm->num_pages = rc; if (rc != num_pages) { if (rc >= 0) rc = -ENOMEM; ret = ERR_PTR(rc); goto err_put_shm_pages; } rc = teedev->desc->ops->shm_register(ctx, shm, shm->pages, shm->num_pages, start); if (rc) { ret = ERR_PTR(rc); goto err_put_shm_pages; } return shm; err_put_shm_pages: if (flags & TEE_SHM_USER_MAPPED) unpin_user_pages(shm->pages, shm->num_pages); else shm_put_kernel_pages(shm->pages, shm->num_pages); kfree(shm->pages); err_free_shm: kfree(shm); err_ctx_put: teedev_ctx_put(ctx); err_dev_put: tee_device_put(teedev); return ret; } /** * tee_shm_register_user_buf() - Register a userspace shared memory buffer * @ctx: Context that registers the shared memory * @addr: The userspace address of the shared buffer * @length: Length of the shared buffer * * @returns a pointer to 'struct tee_shm' */ struct tee_shm *tee_shm_register_user_buf(struct tee_context *ctx, unsigned long addr, size_t length) { u32 flags = TEE_SHM_USER_MAPPED | TEE_SHM_DYNAMIC; struct tee_device *teedev = ctx->teedev; struct tee_shm *shm; void *ret; int id; if (!access_ok((void __user *)addr, length)) return ERR_PTR(-EFAULT); mutex_lock(&teedev->mutex); id = idr_alloc(&teedev->idr, NULL, 1, 0, GFP_KERNEL); mutex_unlock(&teedev->mutex); if (id < 0) return ERR_PTR(id); shm = register_shm_helper(ctx, addr, length, flags, id); if (IS_ERR(shm)) { mutex_lock(&teedev->mutex); idr_remove(&teedev->idr, id); mutex_unlock(&teedev->mutex); return shm; } mutex_lock(&teedev->mutex); ret = idr_replace(&teedev->idr, shm, id); mutex_unlock(&teedev->mutex); if (IS_ERR(ret)) { tee_shm_free(shm); return ret; } return shm; } /** * tee_shm_register_kernel_buf() - Register kernel memory to be shared with * secure world * @ctx: Context that registers the shared memory * @addr: The buffer * @length: Length of the buffer * * @returns a pointer to 'struct tee_shm' */ struct tee_shm *tee_shm_register_kernel_buf(struct tee_context *ctx, void *addr, size_t length) { u32 flags = TEE_SHM_DYNAMIC; return register_shm_helper(ctx, (unsigned long)addr, length, flags, -1); } EXPORT_SYMBOL_GPL(tee_shm_register_kernel_buf); static int tee_shm_fop_release(struct inode *inode, struct file *filp) { tee_shm_put(filp->private_data); return 0; } static int tee_shm_fop_mmap(struct file *filp, struct vm_area_struct *vma) { struct tee_shm *shm = filp->private_data; size_t size = vma->vm_end - vma->vm_start; /* Refuse sharing shared memory provided by application */ if (shm->flags & TEE_SHM_USER_MAPPED) return -EINVAL; /* check for overflowing the buffer's size */ if (vma->vm_pgoff + vma_pages(vma) > shm->size >> PAGE_SHIFT) return -EINVAL; return remap_pfn_range(vma, vma->vm_start, shm->paddr >> PAGE_SHIFT, size, vma->vm_page_prot); } static const struct file_operations tee_shm_fops = { .owner = THIS_MODULE, .release = tee_shm_fop_release, .mmap = tee_shm_fop_mmap, }; /** * tee_shm_get_fd() - Increase reference count and return file descriptor * @shm: Shared memory handle * @returns user space file descriptor to shared memory */ int tee_shm_get_fd(struct tee_shm *shm) { int fd; if (shm->id < 0) return -EINVAL; /* matched by tee_shm_put() in tee_shm_op_release() */ refcount_inc(&shm->refcount); fd = anon_inode_getfd("tee_shm", &tee_shm_fops, shm, O_RDWR); if (fd < 0) tee_shm_put(shm); return fd; } /** * tee_shm_free() - Free shared memory * @shm: Handle to shared memory to free */ void tee_shm_free(struct tee_shm *shm) { tee_shm_put(shm); } EXPORT_SYMBOL_GPL(tee_shm_free); /** * tee_shm_get_va() - Get virtual address of a shared memory plus an offset * @shm: Shared memory handle * @offs: Offset from start of this shared memory * @returns virtual address of the shared memory + offs if offs is within * the bounds of this shared memory, else an ERR_PTR */ void *tee_shm_get_va(struct tee_shm *shm, size_t offs) { if (!shm->kaddr) return ERR_PTR(-EINVAL); if (offs >= shm->size) return ERR_PTR(-EINVAL); return (char *)shm->kaddr + offs; } EXPORT_SYMBOL_GPL(tee_shm_get_va); /** * tee_shm_get_pa() - Get physical address of a shared memory plus an offset * @shm: Shared memory handle * @offs: Offset from start of this shared memory * @pa: Physical address to return * @returns 0 if offs is within the bounds of this shared memory, else an * error code. */ int tee_shm_get_pa(struct tee_shm *shm, size_t offs, phys_addr_t *pa) { if (offs >= shm->size) return -EINVAL; if (pa) *pa = shm->paddr + offs; return 0; } EXPORT_SYMBOL_GPL(tee_shm_get_pa); /** * tee_shm_get_from_id() - Find shared memory object and increase reference * count * @ctx: Context owning the shared memory * @id: Id of shared memory object * @returns a pointer to 'struct tee_shm' on success or an ERR_PTR on failure */ struct tee_shm *tee_shm_get_from_id(struct tee_context *ctx, int id) { struct tee_device *teedev; struct tee_shm *shm; if (!ctx) return ERR_PTR(-EINVAL); teedev = ctx->teedev; mutex_lock(&teedev->mutex); shm = idr_find(&teedev->idr, id); /* * If the tee_shm was found in the IDR it must have a refcount * larger than 0 due to the guarantee in tee_shm_put() below. So * it's safe to use refcount_inc(). */ if (!shm || shm->ctx != ctx) shm = ERR_PTR(-EINVAL); else refcount_inc(&shm->refcount); mutex_unlock(&teedev->mutex); return shm; } EXPORT_SYMBOL_GPL(tee_shm_get_from_id); /** * tee_shm_put() - Decrease reference count on a shared memory handle * @shm: Shared memory handle */ void tee_shm_put(struct tee_shm *shm) { struct tee_device *teedev = shm->ctx->teedev; bool do_release = false; mutex_lock(&teedev->mutex); if (refcount_dec_and_test(&shm->refcount)) { /* * refcount has reached 0, we must now remove it from the * IDR before releasing the mutex. This will guarantee that * the refcount_inc() in tee_shm_get_from_id() never starts * from 0. */ if (shm->id >= 0) idr_remove(&teedev->idr, shm->id); do_release = true; } mutex_unlock(&teedev->mutex); if (do_release) tee_shm_release(teedev, shm); } EXPORT_SYMBOL_GPL(tee_shm_put);