1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2015-2017, 2019-2021 Linaro Limited
4 */
5#include <linux/anon_inodes.h>
6#include <linux/device.h>
7#include <linux/idr.h>
8#include <linux/mm.h>
9#include <linux/sched.h>
10#include <linux/slab.h>
11#include <linux/tee_drv.h>
12#include <linux/uaccess.h>
13#include <linux/uio.h>
14#include <linux/highmem.h>
15#include "tee_private.h"
16
17static void shm_put_kernel_pages(struct page **pages, size_t page_count)
18{
19 size_t n;
20
21 for (n = 0; n < page_count; n++)
22 put_page(page: pages[n]);
23}
24
25static void shm_get_kernel_pages(struct page **pages, size_t page_count)
26{
27 size_t n;
28
29 for (n = 0; n < page_count; n++)
30 get_page(page: pages[n]);
31}
32
33static void release_registered_pages(struct tee_shm *shm)
34{
35 if (shm->pages) {
36 if (shm->flags & TEE_SHM_USER_MAPPED)
37 unpin_user_pages(pages: shm->pages, npages: shm->num_pages);
38 else
39 shm_put_kernel_pages(pages: shm->pages, page_count: shm->num_pages);
40
41 kfree(objp: shm->pages);
42 }
43}
44
45static void tee_shm_release(struct tee_device *teedev, struct tee_shm *shm)
46{
47 if (shm->flags & TEE_SHM_POOL) {
48 teedev->pool->ops->free(teedev->pool, shm);
49 } else if (shm->flags & TEE_SHM_DYNAMIC) {
50 int rc = teedev->desc->ops->shm_unregister(shm->ctx, shm);
51
52 if (rc)
53 dev_err(teedev->dev.parent,
54 "unregister shm %p failed: %d", shm, rc);
55
56 release_registered_pages(shm);
57 }
58
59 teedev_ctx_put(ctx: shm->ctx);
60
61 kfree(objp: shm);
62
63 tee_device_put(teedev);
64}
65
66static struct tee_shm *shm_alloc_helper(struct tee_context *ctx, size_t size,
67 size_t align, u32 flags, int id)
68{
69 struct tee_device *teedev = ctx->teedev;
70 struct tee_shm *shm;
71 void *ret;
72 int rc;
73
74 if (!tee_device_get(teedev))
75 return ERR_PTR(error: -EINVAL);
76
77 if (!teedev->pool) {
78 /* teedev has been detached from driver */
79 ret = ERR_PTR(error: -EINVAL);
80 goto err_dev_put;
81 }
82
83 shm = kzalloc(size: sizeof(*shm), GFP_KERNEL);
84 if (!shm) {
85 ret = ERR_PTR(error: -ENOMEM);
86 goto err_dev_put;
87 }
88
89 refcount_set(r: &shm->refcount, n: 1);
90 shm->flags = flags;
91 shm->id = id;
92
93 /*
94 * We're assigning this as it is needed if the shm is to be
95 * registered. If this function returns OK then the caller expected
96 * to call teedev_ctx_get() or clear shm->ctx in case it's not
97 * needed any longer.
98 */
99 shm->ctx = ctx;
100
101 rc = teedev->pool->ops->alloc(teedev->pool, shm, size, align);
102 if (rc) {
103 ret = ERR_PTR(error: rc);
104 goto err_kfree;
105 }
106
107 teedev_ctx_get(ctx);
108 return shm;
109err_kfree:
110 kfree(objp: shm);
111err_dev_put:
112 tee_device_put(teedev);
113 return ret;
114}
115
116/**
117 * tee_shm_alloc_user_buf() - Allocate shared memory for user space
118 * @ctx: Context that allocates the shared memory
119 * @size: Requested size of shared memory
120 *
121 * Memory allocated as user space shared memory is automatically freed when
122 * the TEE file pointer is closed. The primary usage of this function is
123 * when the TEE driver doesn't support registering ordinary user space
124 * memory.
125 *
126 * @returns a pointer to 'struct tee_shm'
127 */
128struct tee_shm *tee_shm_alloc_user_buf(struct tee_context *ctx, size_t size)
129{
130 u32 flags = TEE_SHM_DYNAMIC | TEE_SHM_POOL;
131 struct tee_device *teedev = ctx->teedev;
132 struct tee_shm *shm;
133 void *ret;
134 int id;
135
136 mutex_lock(&teedev->mutex);
137 id = idr_alloc(&teedev->idr, NULL, start: 1, end: 0, GFP_KERNEL);
138 mutex_unlock(lock: &teedev->mutex);
139 if (id < 0)
140 return ERR_PTR(error: id);
141
142 shm = shm_alloc_helper(ctx, size, PAGE_SIZE, flags, id);
143 if (IS_ERR(ptr: shm)) {
144 mutex_lock(&teedev->mutex);
145 idr_remove(&teedev->idr, id);
146 mutex_unlock(lock: &teedev->mutex);
147 return shm;
148 }
149
150 mutex_lock(&teedev->mutex);
151 ret = idr_replace(&teedev->idr, shm, id);
152 mutex_unlock(lock: &teedev->mutex);
153 if (IS_ERR(ptr: ret)) {
154 tee_shm_free(shm);
155 return ret;
156 }
157
158 return shm;
159}
160
161/**
162 * tee_shm_alloc_kernel_buf() - Allocate shared memory for kernel buffer
163 * @ctx: Context that allocates the shared memory
164 * @size: Requested size of shared memory
165 *
166 * The returned memory registered in secure world and is suitable to be
167 * passed as a memory buffer in parameter argument to
168 * tee_client_invoke_func(). The memory allocated is later freed with a
169 * call to tee_shm_free().
170 *
171 * @returns a pointer to 'struct tee_shm'
172 */
173struct tee_shm *tee_shm_alloc_kernel_buf(struct tee_context *ctx, size_t size)
174{
175 u32 flags = TEE_SHM_DYNAMIC | TEE_SHM_POOL;
176
177 return shm_alloc_helper(ctx, size, PAGE_SIZE, flags, id: -1);
178}
179EXPORT_SYMBOL_GPL(tee_shm_alloc_kernel_buf);
180
181/**
182 * tee_shm_alloc_priv_buf() - Allocate shared memory for a privately shared
183 * kernel buffer
184 * @ctx: Context that allocates the shared memory
185 * @size: Requested size of shared memory
186 *
187 * This function returns similar shared memory as
188 * tee_shm_alloc_kernel_buf(), but with the difference that the memory
189 * might not be registered in secure world in case the driver supports
190 * passing memory not registered in advance.
191 *
192 * This function should normally only be used internally in the TEE
193 * drivers.
194 *
195 * @returns a pointer to 'struct tee_shm'
196 */
197struct tee_shm *tee_shm_alloc_priv_buf(struct tee_context *ctx, size_t size)
198{
199 u32 flags = TEE_SHM_PRIV | TEE_SHM_POOL;
200
201 return shm_alloc_helper(ctx, size, align: sizeof(long) * 2, flags, id: -1);
202}
203EXPORT_SYMBOL_GPL(tee_shm_alloc_priv_buf);
204
205static struct tee_shm *
206register_shm_helper(struct tee_context *ctx, struct iov_iter *iter, u32 flags,
207 int id)
208{
209 struct tee_device *teedev = ctx->teedev;
210 struct tee_shm *shm;
211 unsigned long start, addr;
212 size_t num_pages, off;
213 ssize_t len;
214 void *ret;
215 int rc;
216
217 if (!tee_device_get(teedev))
218 return ERR_PTR(error: -EINVAL);
219
220 if (!teedev->desc->ops->shm_register ||
221 !teedev->desc->ops->shm_unregister) {
222 ret = ERR_PTR(error: -ENOTSUPP);
223 goto err_dev_put;
224 }
225
226 teedev_ctx_get(ctx);
227
228 shm = kzalloc(size: sizeof(*shm), GFP_KERNEL);
229 if (!shm) {
230 ret = ERR_PTR(error: -ENOMEM);
231 goto err_ctx_put;
232 }
233
234 refcount_set(r: &shm->refcount, n: 1);
235 shm->flags = flags;
236 shm->ctx = ctx;
237 shm->id = id;
238 addr = untagged_addr((unsigned long)iter_iov_addr(iter));
239 start = rounddown(addr, PAGE_SIZE);
240 num_pages = iov_iter_npages(i: iter, INT_MAX);
241 if (!num_pages) {
242 ret = ERR_PTR(error: -ENOMEM);
243 goto err_ctx_put;
244 }
245
246 shm->pages = kcalloc(n: num_pages, size: sizeof(*shm->pages), GFP_KERNEL);
247 if (!shm->pages) {
248 ret = ERR_PTR(error: -ENOMEM);
249 goto err_free_shm;
250 }
251
252 len = iov_iter_extract_pages(i: iter, pages: &shm->pages, LONG_MAX, maxpages: num_pages, extraction_flags: 0,
253 offset0: &off);
254 if (unlikely(len <= 0)) {
255 ret = len ? ERR_PTR(error: len) : ERR_PTR(error: -ENOMEM);
256 goto err_free_shm_pages;
257 }
258
259 /*
260 * iov_iter_extract_kvec_pages does not get reference on the pages,
261 * get a reference on them.
262 */
263 if (iov_iter_is_kvec(i: iter))
264 shm_get_kernel_pages(pages: shm->pages, page_count: num_pages);
265
266 shm->offset = off;
267 shm->size = len;
268 shm->num_pages = num_pages;
269
270 rc = teedev->desc->ops->shm_register(ctx, shm, shm->pages,
271 shm->num_pages, start);
272 if (rc) {
273 ret = ERR_PTR(error: rc);
274 goto err_put_shm_pages;
275 }
276
277 return shm;
278err_put_shm_pages:
279 if (!iov_iter_is_kvec(i: iter))
280 unpin_user_pages(pages: shm->pages, npages: shm->num_pages);
281 else
282 shm_put_kernel_pages(pages: shm->pages, page_count: shm->num_pages);
283err_free_shm_pages:
284 kfree(objp: shm->pages);
285err_free_shm:
286 kfree(objp: shm);
287err_ctx_put:
288 teedev_ctx_put(ctx);
289err_dev_put:
290 tee_device_put(teedev);
291 return ret;
292}
293
294/**
295 * tee_shm_register_user_buf() - Register a userspace shared memory buffer
296 * @ctx: Context that registers the shared memory
297 * @addr: The userspace address of the shared buffer
298 * @length: Length of the shared buffer
299 *
300 * @returns a pointer to 'struct tee_shm'
301 */
302struct tee_shm *tee_shm_register_user_buf(struct tee_context *ctx,
303 unsigned long addr, size_t length)
304{
305 u32 flags = TEE_SHM_USER_MAPPED | TEE_SHM_DYNAMIC;
306 struct tee_device *teedev = ctx->teedev;
307 struct tee_shm *shm;
308 struct iov_iter iter;
309 void *ret;
310 int id;
311
312 if (!access_ok((void __user *)addr, length))
313 return ERR_PTR(error: -EFAULT);
314
315 mutex_lock(&teedev->mutex);
316 id = idr_alloc(&teedev->idr, NULL, start: 1, end: 0, GFP_KERNEL);
317 mutex_unlock(lock: &teedev->mutex);
318 if (id < 0)
319 return ERR_PTR(error: id);
320
321 iov_iter_ubuf(i: &iter, ITER_DEST, buf: (void __user *)addr, count: length);
322 shm = register_shm_helper(ctx, iter: &iter, flags, id);
323 if (IS_ERR(ptr: shm)) {
324 mutex_lock(&teedev->mutex);
325 idr_remove(&teedev->idr, id);
326 mutex_unlock(lock: &teedev->mutex);
327 return shm;
328 }
329
330 mutex_lock(&teedev->mutex);
331 ret = idr_replace(&teedev->idr, shm, id);
332 mutex_unlock(lock: &teedev->mutex);
333 if (IS_ERR(ptr: ret)) {
334 tee_shm_free(shm);
335 return ret;
336 }
337
338 return shm;
339}
340
341/**
342 * tee_shm_register_kernel_buf() - Register kernel memory to be shared with
343 * secure world
344 * @ctx: Context that registers the shared memory
345 * @addr: The buffer
346 * @length: Length of the buffer
347 *
348 * @returns a pointer to 'struct tee_shm'
349 */
350
351struct tee_shm *tee_shm_register_kernel_buf(struct tee_context *ctx,
352 void *addr, size_t length)
353{
354 u32 flags = TEE_SHM_DYNAMIC;
355 struct kvec kvec;
356 struct iov_iter iter;
357
358 kvec.iov_base = addr;
359 kvec.iov_len = length;
360 iov_iter_kvec(i: &iter, ITER_DEST, kvec: &kvec, nr_segs: 1, count: length);
361
362 return register_shm_helper(ctx, iter: &iter, flags, id: -1);
363}
364EXPORT_SYMBOL_GPL(tee_shm_register_kernel_buf);
365
366static int tee_shm_fop_release(struct inode *inode, struct file *filp)
367{
368 tee_shm_put(shm: filp->private_data);
369 return 0;
370}
371
372static int tee_shm_fop_mmap(struct file *filp, struct vm_area_struct *vma)
373{
374 struct tee_shm *shm = filp->private_data;
375 size_t size = vma->vm_end - vma->vm_start;
376
377 /* Refuse sharing shared memory provided by application */
378 if (shm->flags & TEE_SHM_USER_MAPPED)
379 return -EINVAL;
380
381 /* check for overflowing the buffer's size */
382 if (vma->vm_pgoff + vma_pages(vma) > shm->size >> PAGE_SHIFT)
383 return -EINVAL;
384
385 return remap_pfn_range(vma, addr: vma->vm_start, pfn: shm->paddr >> PAGE_SHIFT,
386 size, vma->vm_page_prot);
387}
388
389static const struct file_operations tee_shm_fops = {
390 .owner = THIS_MODULE,
391 .release = tee_shm_fop_release,
392 .mmap = tee_shm_fop_mmap,
393};
394
395/**
396 * tee_shm_get_fd() - Increase reference count and return file descriptor
397 * @shm: Shared memory handle
398 * @returns user space file descriptor to shared memory
399 */
400int tee_shm_get_fd(struct tee_shm *shm)
401{
402 int fd;
403
404 if (shm->id < 0)
405 return -EINVAL;
406
407 /* matched by tee_shm_put() in tee_shm_op_release() */
408 refcount_inc(r: &shm->refcount);
409 fd = anon_inode_getfd(name: "tee_shm", fops: &tee_shm_fops, priv: shm, O_RDWR);
410 if (fd < 0)
411 tee_shm_put(shm);
412 return fd;
413}
414
415/**
416 * tee_shm_free() - Free shared memory
417 * @shm: Handle to shared memory to free
418 */
419void tee_shm_free(struct tee_shm *shm)
420{
421 tee_shm_put(shm);
422}
423EXPORT_SYMBOL_GPL(tee_shm_free);
424
425/**
426 * tee_shm_get_va() - Get virtual address of a shared memory plus an offset
427 * @shm: Shared memory handle
428 * @offs: Offset from start of this shared memory
429 * @returns virtual address of the shared memory + offs if offs is within
430 * the bounds of this shared memory, else an ERR_PTR
431 */
432void *tee_shm_get_va(struct tee_shm *shm, size_t offs)
433{
434 if (!shm->kaddr)
435 return ERR_PTR(error: -EINVAL);
436 if (offs >= shm->size)
437 return ERR_PTR(error: -EINVAL);
438 return (char *)shm->kaddr + offs;
439}
440EXPORT_SYMBOL_GPL(tee_shm_get_va);
441
442/**
443 * tee_shm_get_pa() - Get physical address of a shared memory plus an offset
444 * @shm: Shared memory handle
445 * @offs: Offset from start of this shared memory
446 * @pa: Physical address to return
447 * @returns 0 if offs is within the bounds of this shared memory, else an
448 * error code.
449 */
450int tee_shm_get_pa(struct tee_shm *shm, size_t offs, phys_addr_t *pa)
451{
452 if (offs >= shm->size)
453 return -EINVAL;
454 if (pa)
455 *pa = shm->paddr + offs;
456 return 0;
457}
458EXPORT_SYMBOL_GPL(tee_shm_get_pa);
459
460/**
461 * tee_shm_get_from_id() - Find shared memory object and increase reference
462 * count
463 * @ctx: Context owning the shared memory
464 * @id: Id of shared memory object
465 * @returns a pointer to 'struct tee_shm' on success or an ERR_PTR on failure
466 */
467struct tee_shm *tee_shm_get_from_id(struct tee_context *ctx, int id)
468{
469 struct tee_device *teedev;
470 struct tee_shm *shm;
471
472 if (!ctx)
473 return ERR_PTR(error: -EINVAL);
474
475 teedev = ctx->teedev;
476 mutex_lock(&teedev->mutex);
477 shm = idr_find(&teedev->idr, id);
478 /*
479 * If the tee_shm was found in the IDR it must have a refcount
480 * larger than 0 due to the guarantee in tee_shm_put() below. So
481 * it's safe to use refcount_inc().
482 */
483 if (!shm || shm->ctx != ctx)
484 shm = ERR_PTR(error: -EINVAL);
485 else
486 refcount_inc(r: &shm->refcount);
487 mutex_unlock(lock: &teedev->mutex);
488 return shm;
489}
490EXPORT_SYMBOL_GPL(tee_shm_get_from_id);
491
492/**
493 * tee_shm_put() - Decrease reference count on a shared memory handle
494 * @shm: Shared memory handle
495 */
496void tee_shm_put(struct tee_shm *shm)
497{
498 struct tee_device *teedev = shm->ctx->teedev;
499 bool do_release = false;
500
501 mutex_lock(&teedev->mutex);
502 if (refcount_dec_and_test(r: &shm->refcount)) {
503 /*
504 * refcount has reached 0, we must now remove it from the
505 * IDR before releasing the mutex. This will guarantee that
506 * the refcount_inc() in tee_shm_get_from_id() never starts
507 * from 0.
508 */
509 if (shm->id >= 0)
510 idr_remove(&teedev->idr, id: shm->id);
511 do_release = true;
512 }
513 mutex_unlock(lock: &teedev->mutex);
514
515 if (do_release)
516 tee_shm_release(teedev, shm);
517}
518EXPORT_SYMBOL_GPL(tee_shm_put);
519

source code of linux/drivers/tee/tee_shm.c