xref: /openbmc/linux/drivers/tee/tee_shm.c (revision 36fe4655) 
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 <linux/uio.h>
13 #include "tee_private.h"
14 
15 static void release_registered_pages(struct tee_shm *shm)
16 {
17 	if (shm->pages) {
18 		if (shm->flags & TEE_SHM_USER_MAPPED) {
19 			unpin_user_pages(shm->pages, shm->num_pages);
20 		} else {
21 			size_t n;
22 
23 			for (n = 0; n < shm->num_pages; n++)
24 				put_page(shm->pages[n]);
25 		}
26 
27 		kfree(shm->pages);
28 	}
29 }
30 
31 static void tee_shm_release(struct tee_shm *shm)
32 {
33 	struct tee_device *teedev = shm->ctx->teedev;
34 
35 	if (shm->flags & TEE_SHM_DMA_BUF) {
36 		mutex_lock(&teedev->mutex);
37 		idr_remove(&teedev->idr, shm->id);
38 		mutex_unlock(&teedev->mutex);
39 	}
40 
41 	if (shm->flags & TEE_SHM_POOL) {
42 		struct tee_shm_pool_mgr *poolm;
43 
44 		if (shm->flags & TEE_SHM_DMA_BUF)
45 			poolm = teedev->pool->dma_buf_mgr;
46 		else
47 			poolm = teedev->pool->private_mgr;
48 
49 		poolm->ops->free(poolm, shm);
50 	} else if (shm->flags & TEE_SHM_REGISTER) {
51 		int rc = teedev->desc->ops->shm_unregister(shm->ctx, shm);
52 
53 		if (rc)
54 			dev_err(teedev->dev.parent,
55 				"unregister shm %p failed: %d", shm, rc);
56 
57 		release_registered_pages(shm);
58 	}
59 
60 	teedev_ctx_put(shm->ctx);
61 
62 	kfree(shm);
63 
64 	tee_device_put(teedev);
65 }
66 
67 static struct sg_table *tee_shm_op_map_dma_buf(struct dma_buf_attachment
68 			*attach, enum dma_data_direction dir)
69 {
70 	return NULL;
71 }
72 
73 static void tee_shm_op_unmap_dma_buf(struct dma_buf_attachment *attach,
74 				     struct sg_table *table,
75 				     enum dma_data_direction dir)
76 {
77 }
78 
79 static void tee_shm_op_release(struct dma_buf *dmabuf)
80 {
81 	struct tee_shm *shm = dmabuf->priv;
82 
83 	tee_shm_release(shm);
84 }
85 
86 static int tee_shm_op_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
87 {
88 	struct tee_shm *shm = dmabuf->priv;
89 	size_t size = vma->vm_end - vma->vm_start;
90 
91 	/* Refuse sharing shared memory provided by application */
92 	if (shm->flags & TEE_SHM_USER_MAPPED)
93 		return -EINVAL;
94 
95 	return remap_pfn_range(vma, vma->vm_start, shm->paddr >> PAGE_SHIFT,
96 			       size, vma->vm_page_prot);
97 }
98 
99 static const struct dma_buf_ops tee_shm_dma_buf_ops = {
100 	.map_dma_buf = tee_shm_op_map_dma_buf,
101 	.unmap_dma_buf = tee_shm_op_unmap_dma_buf,
102 	.release = tee_shm_op_release,
103 	.mmap = tee_shm_op_mmap,
104 };
105 
106 struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags)
107 {
108 	struct tee_device *teedev = ctx->teedev;
109 	struct tee_shm_pool_mgr *poolm = NULL;
110 	struct tee_shm *shm;
111 	void *ret;
112 	int rc;
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->ctx = ctx;
142 	if (flags & TEE_SHM_DMA_BUF)
143 		poolm = teedev->pool->dma_buf_mgr;
144 	else
145 		poolm = teedev->pool->private_mgr;
146 
147 	rc = poolm->ops->alloc(poolm, shm, size);
148 	if (rc) {
149 		ret = ERR_PTR(rc);
150 		goto err_kfree;
151 	}
152 
153 
154 	if (flags & TEE_SHM_DMA_BUF) {
155 		DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
156 
157 		mutex_lock(&teedev->mutex);
158 		shm->id = idr_alloc(&teedev->idr, shm, 1, 0, GFP_KERNEL);
159 		mutex_unlock(&teedev->mutex);
160 		if (shm->id < 0) {
161 			ret = ERR_PTR(shm->id);
162 			goto err_pool_free;
163 		}
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 	teedev_ctx_get(ctx);
178 
179 	return shm;
180 err_rem:
181 	if (flags & TEE_SHM_DMA_BUF) {
182 		mutex_lock(&teedev->mutex);
183 		idr_remove(&teedev->idr, shm->id);
184 		mutex_unlock(&teedev->mutex);
185 	}
186 err_pool_free:
187 	poolm->ops->free(poolm, shm);
188 err_kfree:
189 	kfree(shm);
190 err_dev_put:
191 	tee_device_put(teedev);
192 	return ret;
193 }
194 EXPORT_SYMBOL_GPL(tee_shm_alloc);
195 
196 struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr,
197 				 size_t length, u32 flags)
198 {
199 	struct tee_device *teedev = ctx->teedev;
200 	const u32 req_user_flags = TEE_SHM_DMA_BUF | TEE_SHM_USER_MAPPED;
201 	const u32 req_kernel_flags = TEE_SHM_DMA_BUF | TEE_SHM_KERNEL_MAPPED;
202 	struct tee_shm *shm;
203 	void *ret;
204 	int rc;
205 	int num_pages;
206 	unsigned long start;
207 
208 	if (flags != req_user_flags && flags != req_kernel_flags)
209 		return ERR_PTR(-ENOTSUPP);
210 
211 	if (!tee_device_get(teedev))
212 		return ERR_PTR(-EINVAL);
213 
214 	if (!teedev->desc->ops->shm_register ||
215 	    !teedev->desc->ops->shm_unregister) {
216 		tee_device_put(teedev);
217 		return ERR_PTR(-ENOTSUPP);
218 	}
219 
220 	teedev_ctx_get(ctx);
221 
222 	shm = kzalloc(sizeof(*shm), GFP_KERNEL);
223 	if (!shm) {
224 		ret = ERR_PTR(-ENOMEM);
225 		goto err;
226 	}
227 
228 	shm->flags = flags | TEE_SHM_REGISTER;
229 	shm->ctx = ctx;
230 	shm->id = -1;
231 	addr = untagged_addr(addr);
232 	start = rounddown(addr, PAGE_SIZE);
233 	shm->offset = addr - start;
234 	shm->size = length;
235 	num_pages = (roundup(addr + length, PAGE_SIZE) - start) / PAGE_SIZE;
236 	shm->pages = kcalloc(num_pages, sizeof(*shm->pages), GFP_KERNEL);
237 	if (!shm->pages) {
238 		ret = ERR_PTR(-ENOMEM);
239 		goto err;
240 	}
241 
242 	if (flags & TEE_SHM_USER_MAPPED) {
243 		rc = pin_user_pages_fast(start, num_pages, FOLL_WRITE,
244 					 shm->pages);
245 	} else {
246 		struct kvec *kiov;
247 		int i;
248 
249 		kiov = kcalloc(num_pages, sizeof(*kiov), GFP_KERNEL);
250 		if (!kiov) {
251 			ret = ERR_PTR(-ENOMEM);
252 			goto err;
253 		}
254 
255 		for (i = 0; i < num_pages; i++) {
256 			kiov[i].iov_base = (void *)(start + i * PAGE_SIZE);
257 			kiov[i].iov_len = PAGE_SIZE;
258 		}
259 
260 		rc = get_kernel_pages(kiov, num_pages, 0, shm->pages);
261 		kfree(kiov);
262 	}
263 	if (rc > 0)
264 		shm->num_pages = rc;
265 	if (rc != num_pages) {
266 		if (rc >= 0)
267 			rc = -ENOMEM;
268 		ret = ERR_PTR(rc);
269 		goto err;
270 	}
271 
272 	mutex_lock(&teedev->mutex);
273 	shm->id = idr_alloc(&teedev->idr, shm, 1, 0, GFP_KERNEL);
274 	mutex_unlock(&teedev->mutex);
275 
276 	if (shm->id < 0) {
277 		ret = ERR_PTR(shm->id);
278 		goto err;
279 	}
280 
281 	rc = teedev->desc->ops->shm_register(ctx, shm, shm->pages,
282 					     shm->num_pages, start);
283 	if (rc) {
284 		ret = ERR_PTR(rc);
285 		goto err;
286 	}
287 
288 	if (flags & TEE_SHM_DMA_BUF) {
289 		DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
290 
291 		exp_info.ops = &tee_shm_dma_buf_ops;
292 		exp_info.size = shm->size;
293 		exp_info.flags = O_RDWR;
294 		exp_info.priv = shm;
295 
296 		shm->dmabuf = dma_buf_export(&exp_info);
297 		if (IS_ERR(shm->dmabuf)) {
298 			ret = ERR_CAST(shm->dmabuf);
299 			teedev->desc->ops->shm_unregister(ctx, shm);
300 			goto err;
301 		}
302 	}
303 
304 	return shm;
305 err:
306 	if (shm) {
307 		if (shm->id >= 0) {
308 			mutex_lock(&teedev->mutex);
309 			idr_remove(&teedev->idr, shm->id);
310 			mutex_unlock(&teedev->mutex);
311 		}
312 		release_registered_pages(shm);
313 	}
314 	kfree(shm);
315 	teedev_ctx_put(ctx);
316 	tee_device_put(teedev);
317 	return ret;
318 }
319 EXPORT_SYMBOL_GPL(tee_shm_register);
320 
321 /**
322  * tee_shm_get_fd() - Increase reference count and return file descriptor
323  * @shm:	Shared memory handle
324  * @returns user space file descriptor to shared memory
325  */
326 int tee_shm_get_fd(struct tee_shm *shm)
327 {
328 	int fd;
329 
330 	if (!(shm->flags & TEE_SHM_DMA_BUF))
331 		return -EINVAL;
332 
333 	get_dma_buf(shm->dmabuf);
334 	fd = dma_buf_fd(shm->dmabuf, O_CLOEXEC);
335 	if (fd < 0)
336 		dma_buf_put(shm->dmabuf);
337 	return fd;
338 }
339 
340 /**
341  * tee_shm_free() - Free shared memory
342  * @shm:	Handle to shared memory to free
343  */
344 void tee_shm_free(struct tee_shm *shm)
345 {
346 	/*
347 	 * dma_buf_put() decreases the dmabuf reference counter and will
348 	 * call tee_shm_release() when the last reference is gone.
349 	 *
350 	 * In the case of driver private memory we call tee_shm_release
351 	 * directly instead as it doesn't have a reference counter.
352 	 */
353 	if (shm->flags & TEE_SHM_DMA_BUF)
354 		dma_buf_put(shm->dmabuf);
355 	else
356 		tee_shm_release(shm);
357 }
358 EXPORT_SYMBOL_GPL(tee_shm_free);
359 
360 /**
361  * tee_shm_va2pa() - Get physical address of a virtual address
362  * @shm:	Shared memory handle
363  * @va:		Virtual address to tranlsate
364  * @pa:		Returned physical address
365  * @returns 0 on success and < 0 on failure
366  */
367 int tee_shm_va2pa(struct tee_shm *shm, void *va, phys_addr_t *pa)
368 {
369 	if (!(shm->flags & TEE_SHM_MAPPED))
370 		return -EINVAL;
371 	/* Check that we're in the range of the shm */
372 	if ((char *)va < (char *)shm->kaddr)
373 		return -EINVAL;
374 	if ((char *)va >= ((char *)shm->kaddr + shm->size))
375 		return -EINVAL;
376 
377 	return tee_shm_get_pa(
378 			shm, (unsigned long)va - (unsigned long)shm->kaddr, pa);
379 }
380 EXPORT_SYMBOL_GPL(tee_shm_va2pa);
381 
382 /**
383  * tee_shm_pa2va() - Get virtual address of a physical address
384  * @shm:	Shared memory handle
385  * @pa:		Physical address to tranlsate
386  * @va:		Returned virtual address
387  * @returns 0 on success and < 0 on failure
388  */
389 int tee_shm_pa2va(struct tee_shm *shm, phys_addr_t pa, void **va)
390 {
391 	if (!(shm->flags & TEE_SHM_MAPPED))
392 		return -EINVAL;
393 	/* Check that we're in the range of the shm */
394 	if (pa < shm->paddr)
395 		return -EINVAL;
396 	if (pa >= (shm->paddr + shm->size))
397 		return -EINVAL;
398 
399 	if (va) {
400 		void *v = tee_shm_get_va(shm, pa - shm->paddr);
401 
402 		if (IS_ERR(v))
403 			return PTR_ERR(v);
404 		*va = v;
405 	}
406 	return 0;
407 }
408 EXPORT_SYMBOL_GPL(tee_shm_pa2va);
409 
410 /**
411  * tee_shm_get_va() - Get virtual address of a shared memory plus an offset
412  * @shm:	Shared memory handle
413  * @offs:	Offset from start of this shared memory
414  * @returns virtual address of the shared memory + offs if offs is within
415  *	the bounds of this shared memory, else an ERR_PTR
416  */
417 void *tee_shm_get_va(struct tee_shm *shm, size_t offs)
418 {
419 	if (!(shm->flags & TEE_SHM_MAPPED))
420 		return ERR_PTR(-EINVAL);
421 	if (offs >= shm->size)
422 		return ERR_PTR(-EINVAL);
423 	return (char *)shm->kaddr + offs;
424 }
425 EXPORT_SYMBOL_GPL(tee_shm_get_va);
426 
427 /**
428  * tee_shm_get_pa() - Get physical address of a shared memory plus an offset
429  * @shm:	Shared memory handle
430  * @offs:	Offset from start of this shared memory
431  * @pa:		Physical address to return
432  * @returns 0 if offs is within the bounds of this shared memory, else an
433  *	error code.
434  */
435 int tee_shm_get_pa(struct tee_shm *shm, size_t offs, phys_addr_t *pa)
436 {
437 	if (offs >= shm->size)
438 		return -EINVAL;
439 	if (pa)
440 		*pa = shm->paddr + offs;
441 	return 0;
442 }
443 EXPORT_SYMBOL_GPL(tee_shm_get_pa);
444 
445 /**
446  * tee_shm_get_from_id() - Find shared memory object and increase reference
447  * count
448  * @ctx:	Context owning the shared memory
449  * @id:		Id of shared memory object
450  * @returns a pointer to 'struct tee_shm' on success or an ERR_PTR on failure
451  */
452 struct tee_shm *tee_shm_get_from_id(struct tee_context *ctx, int id)
453 {
454 	struct tee_device *teedev;
455 	struct tee_shm *shm;
456 
457 	if (!ctx)
458 		return ERR_PTR(-EINVAL);
459 
460 	teedev = ctx->teedev;
461 	mutex_lock(&teedev->mutex);
462 	shm = idr_find(&teedev->idr, id);
463 	if (!shm || shm->ctx != ctx)
464 		shm = ERR_PTR(-EINVAL);
465 	else if (shm->flags & TEE_SHM_DMA_BUF)
466 		get_dma_buf(shm->dmabuf);
467 	mutex_unlock(&teedev->mutex);
468 	return shm;
469 }
470 EXPORT_SYMBOL_GPL(tee_shm_get_from_id);
471 
472 /**
473  * tee_shm_put() - Decrease reference count on a shared memory handle
474  * @shm:	Shared memory handle
475  */
476 void tee_shm_put(struct tee_shm *shm)
477 {
478 	if (shm->flags & TEE_SHM_DMA_BUF)
479 		dma_buf_put(shm->dmabuf);
480 }
481 EXPORT_SYMBOL_GPL(tee_shm_put);
482