xref: /openbmc/linux/drivers/tee/tee_shm.c (revision 2127c01b) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2015-2016, Linaro Limited
4  */
5 #include <linux/device.h>
6 #include <linux/dma-buf.h>
7 #include <linux/fdtable.h>
8 #include <linux/idr.h>
9 #include <linux/sched.h>
10 #include <linux/slab.h>
11 #include <linux/tee_drv.h>
12 #include "tee_private.h"
13 
14 static void tee_shm_release(struct tee_shm *shm)
15 {
16 	struct tee_device *teedev = shm->teedev;
17 
18 	mutex_lock(&teedev->mutex);
19 	idr_remove(&teedev->idr, shm->id);
20 	if (shm->ctx)
21 		list_del(&shm->link);
22 	mutex_unlock(&teedev->mutex);
23 
24 	if (shm->flags & TEE_SHM_POOL) {
25 		struct tee_shm_pool_mgr *poolm;
26 
27 		if (shm->flags & TEE_SHM_DMA_BUF)
28 			poolm = teedev->pool->dma_buf_mgr;
29 		else
30 			poolm = teedev->pool->private_mgr;
31 
32 		poolm->ops->free(poolm, shm);
33 	} else if (shm->flags & TEE_SHM_REGISTER) {
34 		size_t n;
35 		int rc = teedev->desc->ops->shm_unregister(shm->ctx, shm);
36 
37 		if (rc)
38 			dev_err(teedev->dev.parent,
39 				"unregister shm %p failed: %d", shm, rc);
40 
41 		for (n = 0; n < shm->num_pages; n++)
42 			put_page(shm->pages[n]);
43 
44 		kfree(shm->pages);
45 	}
46 
47 	if (shm->ctx)
48 		teedev_ctx_put(shm->ctx);
49 
50 	kfree(shm);
51 
52 	tee_device_put(teedev);
53 }
54 
55 static struct sg_table *tee_shm_op_map_dma_buf(struct dma_buf_attachment
56 			*attach, enum dma_data_direction dir)
57 {
58 	return NULL;
59 }
60 
61 static void tee_shm_op_unmap_dma_buf(struct dma_buf_attachment *attach,
62 				     struct sg_table *table,
63 				     enum dma_data_direction dir)
64 {
65 }
66 
67 static void tee_shm_op_release(struct dma_buf *dmabuf)
68 {
69 	struct tee_shm *shm = dmabuf->priv;
70 
71 	tee_shm_release(shm);
72 }
73 
74 static void *tee_shm_op_map(struct dma_buf *dmabuf, unsigned long pgnum)
75 {
76 	return NULL;
77 }
78 
79 static int tee_shm_op_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
80 {
81 	struct tee_shm *shm = dmabuf->priv;
82 	size_t size = vma->vm_end - vma->vm_start;
83 
84 	/* Refuse sharing shared memory provided by application */
85 	if (shm->flags & TEE_SHM_REGISTER)
86 		return -EINVAL;
87 
88 	return remap_pfn_range(vma, vma->vm_start, shm->paddr >> PAGE_SHIFT,
89 			       size, vma->vm_page_prot);
90 }
91 
92 static const struct dma_buf_ops tee_shm_dma_buf_ops = {
93 	.map_dma_buf = tee_shm_op_map_dma_buf,
94 	.unmap_dma_buf = tee_shm_op_unmap_dma_buf,
95 	.release = tee_shm_op_release,
96 	.map = tee_shm_op_map,
97 	.mmap = tee_shm_op_mmap,
98 };
99 
100 static struct tee_shm *__tee_shm_alloc(struct tee_context *ctx,
101 				       struct tee_device *teedev,
102 				       size_t size, u32 flags)
103 {
104 	struct tee_shm_pool_mgr *poolm = NULL;
105 	struct tee_shm *shm;
106 	void *ret;
107 	int rc;
108 
109 	if (ctx && ctx->teedev != teedev) {
110 		dev_err(teedev->dev.parent, "ctx and teedev mismatch\n");
111 		return ERR_PTR(-EINVAL);
112 	}
113 
114 	if (!(flags & TEE_SHM_MAPPED)) {
115 		dev_err(teedev->dev.parent,
116 			"only mapped allocations supported\n");
117 		return ERR_PTR(-EINVAL);
118 	}
119 
120 	if ((flags & ~(TEE_SHM_MAPPED | TEE_SHM_DMA_BUF))) {
121 		dev_err(teedev->dev.parent, "invalid shm flags 0x%x", flags);
122 		return ERR_PTR(-EINVAL);
123 	}
124 
125 	if (!tee_device_get(teedev))
126 		return ERR_PTR(-EINVAL);
127 
128 	if (!teedev->pool) {
129 		/* teedev has been detached from driver */
130 		ret = ERR_PTR(-EINVAL);
131 		goto err_dev_put;
132 	}
133 
134 	shm = kzalloc(sizeof(*shm), GFP_KERNEL);
135 	if (!shm) {
136 		ret = ERR_PTR(-ENOMEM);
137 		goto err_dev_put;
138 	}
139 
140 	shm->flags = flags | TEE_SHM_POOL;
141 	shm->teedev = teedev;
142 	shm->ctx = ctx;
143 	if (flags & TEE_SHM_DMA_BUF)
144 		poolm = teedev->pool->dma_buf_mgr;
145 	else
146 		poolm = teedev->pool->private_mgr;
147 
148 	rc = poolm->ops->alloc(poolm, shm, size);
149 	if (rc) {
150 		ret = ERR_PTR(rc);
151 		goto err_kfree;
152 	}
153 
154 	mutex_lock(&teedev->mutex);
155 	shm->id = idr_alloc(&teedev->idr, shm, 1, 0, GFP_KERNEL);
156 	mutex_unlock(&teedev->mutex);
157 	if (shm->id < 0) {
158 		ret = ERR_PTR(shm->id);
159 		goto err_pool_free;
160 	}
161 
162 	if (flags & TEE_SHM_DMA_BUF) {
163 		DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
164 
165 		exp_info.ops = &tee_shm_dma_buf_ops;
166 		exp_info.size = shm->size;
167 		exp_info.flags = O_RDWR;
168 		exp_info.priv = shm;
169 
170 		shm->dmabuf = dma_buf_export(&exp_info);
171 		if (IS_ERR(shm->dmabuf)) {
172 			ret = ERR_CAST(shm->dmabuf);
173 			goto err_rem;
174 		}
175 	}
176 
177 	if (ctx) {
178 		teedev_ctx_get(ctx);
179 		mutex_lock(&teedev->mutex);
180 		list_add_tail(&shm->link, &ctx->list_shm);
181 		mutex_unlock(&teedev->mutex);
182 	}
183 
184 	return shm;
185 err_rem:
186 	mutex_lock(&teedev->mutex);
187 	idr_remove(&teedev->idr, shm->id);
188 	mutex_unlock(&teedev->mutex);
189 err_pool_free:
190 	poolm->ops->free(poolm, shm);
191 err_kfree:
192 	kfree(shm);
193 err_dev_put:
194 	tee_device_put(teedev);
195 	return ret;
196 }
197 
198 /**
199  * tee_shm_alloc() - Allocate shared memory
200  * @ctx:	Context that allocates the shared memory
201  * @size:	Requested size of shared memory
202  * @flags:	Flags setting properties for the requested shared memory.
203  *
204  * Memory allocated as global shared memory is automatically freed when the
205  * TEE file pointer is closed. The @flags field uses the bits defined by
206  * TEE_SHM_* in <linux/tee_drv.h>. TEE_SHM_MAPPED must currently always be
207  * set. If TEE_SHM_DMA_BUF global shared memory will be allocated and
208  * associated with a dma-buf handle, else driver private memory.
209  */
210 struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags)
211 {
212 	return __tee_shm_alloc(ctx, ctx->teedev, size, flags);
213 }
214 EXPORT_SYMBOL_GPL(tee_shm_alloc);
215 
216 struct tee_shm *tee_shm_priv_alloc(struct tee_device *teedev, size_t size)
217 {
218 	return __tee_shm_alloc(NULL, teedev, size, TEE_SHM_MAPPED);
219 }
220 EXPORT_SYMBOL_GPL(tee_shm_priv_alloc);
221 
222 struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr,
223 				 size_t length, u32 flags)
224 {
225 	struct tee_device *teedev = ctx->teedev;
226 	const u32 req_flags = TEE_SHM_DMA_BUF | TEE_SHM_USER_MAPPED;
227 	struct tee_shm *shm;
228 	void *ret;
229 	int rc;
230 	int num_pages;
231 	unsigned long start;
232 
233 	if (flags != req_flags)
234 		return ERR_PTR(-ENOTSUPP);
235 
236 	if (!tee_device_get(teedev))
237 		return ERR_PTR(-EINVAL);
238 
239 	if (!teedev->desc->ops->shm_register ||
240 	    !teedev->desc->ops->shm_unregister) {
241 		tee_device_put(teedev);
242 		return ERR_PTR(-ENOTSUPP);
243 	}
244 
245 	teedev_ctx_get(ctx);
246 
247 	shm = kzalloc(sizeof(*shm), GFP_KERNEL);
248 	if (!shm) {
249 		ret = ERR_PTR(-ENOMEM);
250 		goto err;
251 	}
252 
253 	shm->flags = flags | TEE_SHM_REGISTER;
254 	shm->teedev = teedev;
255 	shm->ctx = ctx;
256 	shm->id = -1;
257 	start = rounddown(addr, PAGE_SIZE);
258 	shm->offset = addr - start;
259 	shm->size = length;
260 	num_pages = (roundup(addr + length, PAGE_SIZE) - start) / PAGE_SIZE;
261 	shm->pages = kcalloc(num_pages, sizeof(*shm->pages), GFP_KERNEL);
262 	if (!shm->pages) {
263 		ret = ERR_PTR(-ENOMEM);
264 		goto err;
265 	}
266 
267 	rc = get_user_pages_fast(start, num_pages, FOLL_WRITE, shm->pages);
268 	if (rc > 0)
269 		shm->num_pages = rc;
270 	if (rc != num_pages) {
271 		if (rc >= 0)
272 			rc = -ENOMEM;
273 		ret = ERR_PTR(rc);
274 		goto err;
275 	}
276 
277 	mutex_lock(&teedev->mutex);
278 	shm->id = idr_alloc(&teedev->idr, shm, 1, 0, GFP_KERNEL);
279 	mutex_unlock(&teedev->mutex);
280 
281 	if (shm->id < 0) {
282 		ret = ERR_PTR(shm->id);
283 		goto err;
284 	}
285 
286 	rc = teedev->desc->ops->shm_register(ctx, shm, shm->pages,
287 					     shm->num_pages, start);
288 	if (rc) {
289 		ret = ERR_PTR(rc);
290 		goto err;
291 	}
292 
293 	if (flags & TEE_SHM_DMA_BUF) {
294 		DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
295 
296 		exp_info.ops = &tee_shm_dma_buf_ops;
297 		exp_info.size = shm->size;
298 		exp_info.flags = O_RDWR;
299 		exp_info.priv = shm;
300 
301 		shm->dmabuf = dma_buf_export(&exp_info);
302 		if (IS_ERR(shm->dmabuf)) {
303 			ret = ERR_CAST(shm->dmabuf);
304 			teedev->desc->ops->shm_unregister(ctx, shm);
305 			goto err;
306 		}
307 	}
308 
309 	mutex_lock(&teedev->mutex);
310 	list_add_tail(&shm->link, &ctx->list_shm);
311 	mutex_unlock(&teedev->mutex);
312 
313 	return shm;
314 err:
315 	if (shm) {
316 		size_t n;
317 
318 		if (shm->id >= 0) {
319 			mutex_lock(&teedev->mutex);
320 			idr_remove(&teedev->idr, shm->id);
321 			mutex_unlock(&teedev->mutex);
322 		}
323 		if (shm->pages) {
324 			for (n = 0; n < shm->num_pages; n++)
325 				put_page(shm->pages[n]);
326 			kfree(shm->pages);
327 		}
328 	}
329 	kfree(shm);
330 	teedev_ctx_put(ctx);
331 	tee_device_put(teedev);
332 	return ret;
333 }
334 EXPORT_SYMBOL_GPL(tee_shm_register);
335 
336 /**
337  * tee_shm_get_fd() - Increase reference count and return file descriptor
338  * @shm:	Shared memory handle
339  * @returns user space file descriptor to shared memory
340  */
341 int tee_shm_get_fd(struct tee_shm *shm)
342 {
343 	int fd;
344 
345 	if (!(shm->flags & TEE_SHM_DMA_BUF))
346 		return -EINVAL;
347 
348 	get_dma_buf(shm->dmabuf);
349 	fd = dma_buf_fd(shm->dmabuf, O_CLOEXEC);
350 	if (fd < 0)
351 		dma_buf_put(shm->dmabuf);
352 	return fd;
353 }
354 
355 /**
356  * tee_shm_free() - Free shared memory
357  * @shm:	Handle to shared memory to free
358  */
359 void tee_shm_free(struct tee_shm *shm)
360 {
361 	/*
362 	 * dma_buf_put() decreases the dmabuf reference counter and will
363 	 * call tee_shm_release() when the last reference is gone.
364 	 *
365 	 * In the case of driver private memory we call tee_shm_release
366 	 * directly instead as it doesn't have a reference counter.
367 	 */
368 	if (shm->flags & TEE_SHM_DMA_BUF)
369 		dma_buf_put(shm->dmabuf);
370 	else
371 		tee_shm_release(shm);
372 }
373 EXPORT_SYMBOL_GPL(tee_shm_free);
374 
375 /**
376  * tee_shm_va2pa() - Get physical address of a virtual address
377  * @shm:	Shared memory handle
378  * @va:		Virtual address to tranlsate
379  * @pa:		Returned physical address
380  * @returns 0 on success and < 0 on failure
381  */
382 int tee_shm_va2pa(struct tee_shm *shm, void *va, phys_addr_t *pa)
383 {
384 	if (!(shm->flags & TEE_SHM_MAPPED))
385 		return -EINVAL;
386 	/* Check that we're in the range of the shm */
387 	if ((char *)va < (char *)shm->kaddr)
388 		return -EINVAL;
389 	if ((char *)va >= ((char *)shm->kaddr + shm->size))
390 		return -EINVAL;
391 
392 	return tee_shm_get_pa(
393 			shm, (unsigned long)va - (unsigned long)shm->kaddr, pa);
394 }
395 EXPORT_SYMBOL_GPL(tee_shm_va2pa);
396 
397 /**
398  * tee_shm_pa2va() - Get virtual address of a physical address
399  * @shm:	Shared memory handle
400  * @pa:		Physical address to tranlsate
401  * @va:		Returned virtual address
402  * @returns 0 on success and < 0 on failure
403  */
404 int tee_shm_pa2va(struct tee_shm *shm, phys_addr_t pa, void **va)
405 {
406 	if (!(shm->flags & TEE_SHM_MAPPED))
407 		return -EINVAL;
408 	/* Check that we're in the range of the shm */
409 	if (pa < shm->paddr)
410 		return -EINVAL;
411 	if (pa >= (shm->paddr + shm->size))
412 		return -EINVAL;
413 
414 	if (va) {
415 		void *v = tee_shm_get_va(shm, pa - shm->paddr);
416 
417 		if (IS_ERR(v))
418 			return PTR_ERR(v);
419 		*va = v;
420 	}
421 	return 0;
422 }
423 EXPORT_SYMBOL_GPL(tee_shm_pa2va);
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  */
432 void *tee_shm_get_va(struct tee_shm *shm, size_t offs)
433 {
434 	if (!(shm->flags & TEE_SHM_MAPPED))
435 		return ERR_PTR(-EINVAL);
436 	if (offs >= shm->size)
437 		return ERR_PTR(-EINVAL);
438 	return (char *)shm->kaddr + offs;
439 }
440 EXPORT_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  */
450 int 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 }
458 EXPORT_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  */
467 struct 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(-EINVAL);
474 
475 	teedev = ctx->teedev;
476 	mutex_lock(&teedev->mutex);
477 	shm = idr_find(&teedev->idr, id);
478 	if (!shm || shm->ctx != ctx)
479 		shm = ERR_PTR(-EINVAL);
480 	else if (shm->flags & TEE_SHM_DMA_BUF)
481 		get_dma_buf(shm->dmabuf);
482 	mutex_unlock(&teedev->mutex);
483 	return shm;
484 }
485 EXPORT_SYMBOL_GPL(tee_shm_get_from_id);
486 
487 /**
488  * tee_shm_put() - Decrease reference count on a shared memory handle
489  * @shm:	Shared memory handle
490  */
491 void tee_shm_put(struct tee_shm *shm)
492 {
493 	if (shm->flags & TEE_SHM_DMA_BUF)
494 		dma_buf_put(shm->dmabuf);
495 }
496 EXPORT_SYMBOL_GPL(tee_shm_put);
497