xref: /optee_os/core/arch/arm/mm/mobj_ffa.c (revision c6c416f1bf4617feef23d592155ba7de69bceea9) 
1 // SPDX-License-Identifier: BSD-2-Clause
2 /*
3  * Copyright (c) 2016-2020, Linaro Limited
4  */
5 
6 #include <assert.h>
7 #include <bitstring.h>
8 #include <ffa.h>
9 #include <initcall.h>
10 #include <keep.h>
11 #include <kernel/refcount.h>
12 #include <kernel/spinlock.h>
13 #include <kernel/thread_spmc.h>
14 #include <mm/mobj.h>
15 #include <sys/queue.h>
16 
17 struct mobj_ffa {
18 	struct mobj mobj;
19 	SLIST_ENTRY(mobj_ffa) link;
20 	uint64_t cookie;
21 	tee_mm_entry_t *mm;
22 	struct refcount mapcount;
23 	uint16_t page_offset;
24 #ifdef CFG_CORE_SEL1_SPMC
25 	bool registered_by_cookie;
26 	bool unregistered_by_cookie;
27 #endif
28 	paddr_t pages[];
29 };
30 
31 SLIST_HEAD(mobj_ffa_head, mobj_ffa);
32 
33 #ifdef CFG_CORE_SEL1_SPMC
34 #define NUM_SHMS	64
35 static bitstr_t bit_decl(shm_bits, NUM_SHMS);
36 #endif
37 
38 static struct mobj_ffa_head shm_head = SLIST_HEAD_INITIALIZER(shm_head);
39 static struct mobj_ffa_head shm_inactive_head =
40 	SLIST_HEAD_INITIALIZER(shm_inactive_head);
41 
42 static unsigned int shm_lock = SPINLOCK_UNLOCK;
43 
44 const struct mobj_ops mobj_ffa_ops;
45 
46 static struct mobj_ffa *to_mobj_ffa(struct mobj *mobj)
47 {
48 	assert(mobj->ops == &mobj_ffa_ops);
49 	return container_of(mobj, struct mobj_ffa, mobj);
50 }
51 
52 static size_t shm_size(size_t num_pages)
53 {
54 	size_t s = 0;
55 
56 	if (MUL_OVERFLOW(sizeof(paddr_t), num_pages, &s))
57 		return 0;
58 	if (ADD_OVERFLOW(sizeof(struct mobj_ffa), s, &s))
59 		return 0;
60 	return s;
61 }
62 
63 static struct mobj_ffa *ffa_new(unsigned int num_pages)
64 {
65 	struct mobj_ffa *mf = NULL;
66 	size_t s = 0;
67 
68 	if (!num_pages)
69 		return NULL;
70 
71 	s = shm_size(num_pages);
72 	if (!s)
73 		return NULL;
74 	mf = calloc(1, s);
75 	if (!mf)
76 		return NULL;
77 
78 	mf->mobj.ops = &mobj_ffa_ops;
79 	mf->mobj.size = num_pages * SMALL_PAGE_SIZE;
80 	mf->mobj.phys_granule = SMALL_PAGE_SIZE;
81 	refcount_set(&mf->mobj.refc, 0);
82 
83 	return mf;
84 }
85 
86 #ifdef CFG_CORE_SEL1_SPMC
87 struct mobj_ffa *mobj_ffa_sel1_spmc_new(unsigned int num_pages)
88 {
89 	struct mobj_ffa *mf = NULL;
90 	uint32_t exceptions = 0;
91 	int i = 0;
92 
93 	mf = ffa_new(num_pages);
94 	if (!mf)
95 		return NULL;
96 
97 	exceptions = cpu_spin_lock_xsave(&shm_lock);
98 	bit_ffc(shm_bits, NUM_SHMS, &i);
99 	if (i != -1) {
100 		bit_set(shm_bits, i);
101 		/*
102 		 * Setting bit 44 to use one of the upper 32 bits too for
103 		 * testing.
104 		 */
105 		mf->cookie = i | FFA_MEMORY_HANDLE_NONE_SECURE_BIT;
106 
107 	}
108 	cpu_spin_unlock_xrestore(&shm_lock, exceptions);
109 
110 	if (i == -1) {
111 		free(mf);
112 		return NULL;
113 	}
114 
115 	return mf;
116 }
117 #endif /*CFG_CORE_SEL1_SPMC*/
118 
119 static size_t get_page_count(struct mobj_ffa *mf)
120 {
121 	return ROUNDUP(mf->mobj.size, SMALL_PAGE_SIZE) / SMALL_PAGE_SIZE;
122 }
123 
124 static bool cmp_cookie(struct mobj_ffa *mf, uint64_t cookie)
125 {
126 	return mf->cookie == cookie;
127 }
128 
129 static bool cmp_ptr(struct mobj_ffa *mf, uint64_t ptr)
130 {
131 	return mf == (void *)(vaddr_t)ptr;
132 }
133 
134 static struct mobj_ffa *pop_from_list(struct mobj_ffa_head *head,
135 				      bool (*cmp_func)(struct mobj_ffa *mf,
136 						       uint64_t val),
137 				      uint64_t val)
138 {
139 	struct mobj_ffa *mf = SLIST_FIRST(head);
140 	struct mobj_ffa *p = NULL;
141 
142 	if (!mf)
143 		return NULL;
144 
145 	if (cmp_func(mf, val)) {
146 		SLIST_REMOVE_HEAD(head, link);
147 		return mf;
148 	}
149 
150 	while (true) {
151 		p = SLIST_NEXT(mf, link);
152 		if (!p)
153 			return NULL;
154 		if (cmp_func(p, val)) {
155 			SLIST_REMOVE_AFTER(mf, link);
156 			return p;
157 		}
158 		mf = p;
159 	}
160 }
161 
162 static struct mobj_ffa *find_in_list(struct mobj_ffa_head *head,
163 				     bool (*cmp_func)(struct mobj_ffa *mf,
164 						      uint64_t val),
165 				     uint64_t val)
166 {
167 	struct mobj_ffa *mf = NULL;
168 
169 	SLIST_FOREACH(mf, head, link)
170 		if (cmp_func(mf, val))
171 			return mf;
172 
173 	return NULL;
174 }
175 
176 #ifdef CFG_CORE_SEL1_SPMC
177 void mobj_ffa_sel1_spmc_delete(struct mobj_ffa *mf)
178 {
179 	int i = mf->cookie & ~BIT64(44);
180 	uint32_t exceptions = 0;
181 
182 	assert(i >= 0 && i < NUM_SHMS);
183 
184 	exceptions = cpu_spin_lock_xsave(&shm_lock);
185 	assert(bit_test(shm_bits, i));
186 	bit_clear(shm_bits, i);
187 	assert(!mf->mm);
188 	cpu_spin_unlock_xrestore(&shm_lock, exceptions);
189 
190 	free(mf);
191 }
192 #endif /*CFG_CORE_SEL1_SPMC*/
193 
194 #ifdef CFG_CORE_SEL2_SPMC
195 struct mobj_ffa *mobj_ffa_sel2_spmc_new(uint64_t cookie,
196 					unsigned int num_pages)
197 {
198 	struct mobj_ffa *mf = NULL;
199 
200 	assert(cookie != OPTEE_MSG_FMEM_INVALID_GLOBAL_ID);
201 	mf = ffa_new(num_pages);
202 	if (mf)
203 		mf->cookie = cookie;
204 	return mf;
205 }
206 
207 void mobj_ffa_sel2_spmc_delete(struct mobj_ffa *mf)
208 {
209 	free(mf);
210 }
211 #endif /*CFG_CORE_SEL2_SPMC*/
212 
213 TEE_Result mobj_ffa_add_pages_at(struct mobj_ffa *mf, unsigned int *idx,
214 				 paddr_t pa, unsigned int num_pages)
215 {
216 	unsigned int n = 0;
217 	size_t tot_page_count = get_page_count(mf);
218 
219 	if (ADD_OVERFLOW(*idx, num_pages, &n) || n > tot_page_count)
220 		return TEE_ERROR_BAD_PARAMETERS;
221 
222 	if (!core_pbuf_is(CORE_MEM_NON_SEC, pa, num_pages * SMALL_PAGE_SIZE))
223 		return TEE_ERROR_BAD_PARAMETERS;
224 
225 	for (n = 0; n < num_pages; n++)
226 		mf->pages[n + *idx] = pa + n * SMALL_PAGE_SIZE;
227 
228 	(*idx) += n;
229 	return TEE_SUCCESS;
230 }
231 
232 uint64_t mobj_ffa_get_cookie(struct mobj_ffa *mf)
233 {
234 	return mf->cookie;
235 }
236 
237 uint64_t mobj_ffa_push_to_inactive(struct mobj_ffa *mf)
238 {
239 	uint32_t exceptions = 0;
240 
241 	exceptions = cpu_spin_lock_xsave(&shm_lock);
242 	assert(!find_in_list(&shm_inactive_head, cmp_ptr, (vaddr_t)mf));
243 	assert(!find_in_list(&shm_inactive_head, cmp_cookie, mf->cookie));
244 	assert(!find_in_list(&shm_head, cmp_cookie, mf->cookie));
245 	SLIST_INSERT_HEAD(&shm_inactive_head, mf, link);
246 	cpu_spin_unlock_xrestore(&shm_lock, exceptions);
247 
248 	return mf->cookie;
249 }
250 
251 static void unmap_helper(struct mobj_ffa *mf)
252 {
253 	if (mf->mm) {
254 		core_mmu_unmap_pages(tee_mm_get_smem(mf->mm),
255 				     get_page_count(mf));
256 		tee_mm_free(mf->mm);
257 		mf->mm = NULL;
258 	}
259 }
260 
261 #ifdef CFG_CORE_SEL1_SPMC
262 TEE_Result mobj_ffa_sel1_spmc_reclaim(uint64_t cookie)
263 {
264 	TEE_Result res = TEE_SUCCESS;
265 	struct mobj_ffa *mf = NULL;
266 	uint32_t exceptions = 0;
267 
268 	exceptions = cpu_spin_lock_xsave(&shm_lock);
269 	mf = find_in_list(&shm_head, cmp_cookie, cookie);
270 	/*
271 	 * If the mobj is found here it's still active and cannot be
272 	 * reclaimed.
273 	 */
274 	if (mf) {
275 		DMSG("cookie %#"PRIx64" busy refc %u",
276 		     cookie, refcount_val(&mf->mobj.refc));
277 		res = TEE_ERROR_BUSY;
278 		goto out;
279 	}
280 
281 	mf = find_in_list(&shm_inactive_head, cmp_cookie, cookie);
282 	if (!mf) {
283 		res = TEE_ERROR_ITEM_NOT_FOUND;
284 		goto out;
285 	}
286 	/*
287 	 * If the mobj has been registered via mobj_ffa_get_by_cookie()
288 	 * but not unregistered yet with mobj_ffa_unregister_by_cookie().
289 	 */
290 	if (mf->registered_by_cookie && !mf->unregistered_by_cookie) {
291 		DMSG("cookie %#"PRIx64" busy", cookie);
292 		res = TEE_ERROR_BUSY;
293 		goto out;
294 	}
295 
296 	if (!pop_from_list(&shm_inactive_head, cmp_ptr, (vaddr_t)mf))
297 		panic();
298 	res = TEE_SUCCESS;
299 out:
300 	cpu_spin_unlock_xrestore(&shm_lock, exceptions);
301 	if (!res)
302 		mobj_ffa_sel1_spmc_delete(mf);
303 	return res;
304 }
305 #endif /*CFG_CORE_SEL1_SPMC*/
306 
307 TEE_Result mobj_ffa_unregister_by_cookie(uint64_t cookie)
308 {
309 	TEE_Result res = TEE_SUCCESS;
310 	struct mobj_ffa *mf = NULL;
311 	uint32_t exceptions = 0;
312 
313 	assert(cookie != OPTEE_MSG_FMEM_INVALID_GLOBAL_ID);
314 	exceptions = cpu_spin_lock_xsave(&shm_lock);
315 	mf = find_in_list(&shm_head, cmp_cookie, cookie);
316 	/*
317 	 * If the mobj is found here it's still active and cannot be
318 	 * unregistered.
319 	 */
320 	if (mf) {
321 		DMSG("cookie %#"PRIx64" busy refc %u",
322 		     cookie, refcount_val(&mf->mobj.refc));
323 		res = TEE_ERROR_BUSY;
324 		goto out;
325 	}
326 	mf = find_in_list(&shm_inactive_head, cmp_cookie, cookie);
327 	/*
328 	 * If the mobj isn't found or if it already has been unregistered.
329 	 */
330 #ifdef CFG_CORE_SEL2_SPMC
331 	if (!mf) {
332 #else
333 	if (!mf || mf->unregistered_by_cookie) {
334 #endif
335 		res = TEE_ERROR_ITEM_NOT_FOUND;
336 		goto out;
337 	}
338 
339 #ifdef CFG_CORE_SEL2_SPMC
340 	mf = pop_from_list(&shm_inactive_head, cmp_cookie, cookie);
341 	mobj_ffa_sel2_spmc_delete(mf);
342 	thread_spmc_relinquish(cookie);
343 #else
344 	mf->unregistered_by_cookie = true;
345 #endif
346 	res = TEE_SUCCESS;
347 
348 out:
349 	cpu_spin_unlock_xrestore(&shm_lock, exceptions);
350 	return res;
351 }
352 
353 struct mobj *mobj_ffa_get_by_cookie(uint64_t cookie,
354 				    unsigned int internal_offs)
355 {
356 	struct mobj_ffa *mf = NULL;
357 	uint32_t exceptions = 0;
358 
359 	if (internal_offs >= SMALL_PAGE_SIZE)
360 		return NULL;
361 	exceptions = cpu_spin_lock_xsave(&shm_lock);
362 	mf = find_in_list(&shm_head, cmp_cookie, cookie);
363 	if (mf) {
364 		if (mf->page_offset == internal_offs) {
365 			if (!refcount_inc(&mf->mobj.refc)) {
366 				/*
367 				 * If refcount is 0 some other thread has
368 				 * called mobj_put() on this reached 0 and
369 				 * before ffa_inactivate() got the lock we
370 				 * found it. Let's reinitialize it.
371 				 */
372 				refcount_set(&mf->mobj.refc, 1);
373 			}
374 			DMSG("cookie %#"PRIx64" active: refc %d",
375 			     cookie, refcount_val(&mf->mobj.refc));
376 		} else {
377 			EMSG("cookie %#"PRIx64" mismatching internal_offs got %#"PRIx16" expected %#x",
378 			     cookie, mf->page_offset, internal_offs);
379 			mf = NULL;
380 		}
381 	} else {
382 		mf = pop_from_list(&shm_inactive_head, cmp_cookie, cookie);
383 #if defined(CFG_CORE_SEL2_SPMC)
384 		/* Try to retrieve it from the SPM at S-EL2 */
385 		if (mf) {
386 			DMSG("cookie %#"PRIx64" resurrecting", cookie);
387 		} else {
388 			EMSG("Populating mobj from rx buffer, cookie %#"PRIx64,
389 			     cookie);
390 			mf = thread_spmc_populate_mobj_from_rx(cookie);
391 		}
392 #endif
393 		if (mf) {
394 #if defined(CFG_CORE_SEL1_SPMC)
395 			mf->unregistered_by_cookie = false;
396 			mf->registered_by_cookie = true;
397 #endif
398 			assert(refcount_val(&mf->mobj.refc) == 0);
399 			refcount_set(&mf->mobj.refc, 1);
400 			refcount_set(&mf->mapcount, 0);
401 
402 			/*
403 			 * mf->page_offset is offset into the first page.
404 			 * This offset is assigned from the internal_offs
405 			 * parameter to this function.
406 			 *
407 			 * While a mobj_ffa is active (ref_count > 0) this
408 			 * will not change, but when being pushed to the
409 			 * inactive list it can be changed again.
410 			 *
411 			 * So below we're backing out the old
412 			 * mf->page_offset and then assigning a new from
413 			 * internal_offset.
414 			 */
415 			mf->mobj.size += mf->page_offset;
416 			assert(!(mf->mobj.size & SMALL_PAGE_MASK));
417 			mf->mobj.size -= internal_offs;
418 			mf->page_offset = internal_offs;
419 
420 			SLIST_INSERT_HEAD(&shm_head, mf, link);
421 		}
422 	}
423 
424 	cpu_spin_unlock_xrestore(&shm_lock, exceptions);
425 
426 	if (!mf) {
427 		EMSG("Failed to get cookie %#"PRIx64" internal_offs %#x",
428 		     cookie, internal_offs);
429 		return NULL;
430 	}
431 	return &mf->mobj;
432 }
433 
434 static TEE_Result ffa_get_pa(struct mobj *mobj, size_t offset,
435 			     size_t granule, paddr_t *pa)
436 {
437 	struct mobj_ffa *mf = to_mobj_ffa(mobj);
438 	size_t full_offset = 0;
439 	paddr_t p = 0;
440 
441 	if (!pa)
442 		return TEE_ERROR_GENERIC;
443 
444 	if (offset >= mobj->size)
445 		return TEE_ERROR_GENERIC;
446 
447 	full_offset = offset + mf->page_offset;
448 	switch (granule) {
449 	case 0:
450 		p = mf->pages[full_offset / SMALL_PAGE_SIZE] +
451 		    (full_offset & SMALL_PAGE_MASK);
452 		break;
453 	case SMALL_PAGE_SIZE:
454 		p = mf->pages[full_offset / SMALL_PAGE_SIZE];
455 		break;
456 	default:
457 		return TEE_ERROR_GENERIC;
458 	}
459 	*pa = p;
460 
461 	return TEE_SUCCESS;
462 }
463 DECLARE_KEEP_PAGER(ffa_get_pa);
464 
465 static size_t ffa_get_phys_offs(struct mobj *mobj,
466 				size_t granule __maybe_unused)
467 {
468 	assert(granule >= mobj->phys_granule);
469 
470 	return to_mobj_ffa(mobj)->page_offset;
471 }
472 
473 static void *ffa_get_va(struct mobj *mobj, size_t offset, size_t len)
474 {
475 	struct mobj_ffa *mf = to_mobj_ffa(mobj);
476 
477 	if (!mf->mm || !mobj_check_offset_and_len(mobj, offset, len))
478 		return NULL;
479 
480 	return (void *)(tee_mm_get_smem(mf->mm) + offset + mf->page_offset);
481 }
482 
483 static void ffa_inactivate(struct mobj *mobj)
484 {
485 	struct mobj_ffa *mf = to_mobj_ffa(mobj);
486 	uint32_t exceptions = 0;
487 
488 	exceptions = cpu_spin_lock_xsave(&shm_lock);
489 	/*
490 	 * If refcount isn't 0 some other thread has found this mobj in
491 	 * shm_head after the mobj_put() that put us here and before we got
492 	 * the lock.
493 	 */
494 	if (refcount_val(&mobj->refc)) {
495 		DMSG("cookie %#"PRIx64" was resurrected", mf->cookie);
496 		goto out;
497 	}
498 
499 	DMSG("cookie %#"PRIx64, mf->cookie);
500 	if (!pop_from_list(&shm_head, cmp_ptr, (vaddr_t)mf))
501 		panic();
502 	unmap_helper(mf);
503 	SLIST_INSERT_HEAD(&shm_inactive_head, mf, link);
504 out:
505 	cpu_spin_unlock_xrestore(&shm_lock, exceptions);
506 }
507 
508 static TEE_Result ffa_get_cattr(struct mobj *mobj __unused, uint32_t *cattr)
509 {
510 	if (!cattr)
511 		return TEE_ERROR_GENERIC;
512 
513 	*cattr = TEE_MATTR_CACHE_CACHED;
514 
515 	return TEE_SUCCESS;
516 }
517 
518 static bool ffa_matches(struct mobj *mobj __maybe_unused, enum buf_is_attr attr)
519 {
520 	assert(mobj->ops == &mobj_ffa_ops);
521 
522 	return attr == CORE_MEM_NON_SEC || attr == CORE_MEM_REG_SHM;
523 }
524 
525 static uint64_t ffa_get_cookie(struct mobj *mobj)
526 {
527 	return to_mobj_ffa(mobj)->cookie;
528 }
529 
530 static TEE_Result ffa_inc_map(struct mobj *mobj)
531 {
532 	TEE_Result res = TEE_SUCCESS;
533 	struct mobj_ffa *mf = to_mobj_ffa(mobj);
534 	uint32_t exceptions = 0;
535 	size_t sz = 0;
536 
537 	while (true) {
538 		if (refcount_inc(&mf->mapcount))
539 			return TEE_SUCCESS;
540 
541 		exceptions = cpu_spin_lock_xsave(&shm_lock);
542 
543 		if (!refcount_val(&mf->mapcount))
544 			break; /* continue to reinitialize */
545 		/*
546 		 * If another thread beat us to initialize mapcount,
547 		 * restart to make sure we still increase it.
548 		 */
549 		cpu_spin_unlock_xrestore(&shm_lock, exceptions);
550 	}
551 
552 	/*
553 	 * If we have beated another thread calling ffa_dec_map()
554 	 * to get the lock we need only to reinitialize mapcount to 1.
555 	 */
556 	if (!mf->mm) {
557 		sz = ROUNDUP(mobj->size + mf->page_offset, SMALL_PAGE_SIZE);
558 		mf->mm = tee_mm_alloc(&tee_mm_shm, sz);
559 		if (!mf->mm) {
560 			res = TEE_ERROR_OUT_OF_MEMORY;
561 			goto out;
562 		}
563 
564 		res = core_mmu_map_pages(tee_mm_get_smem(mf->mm), mf->pages,
565 					 sz / SMALL_PAGE_SIZE,
566 					 MEM_AREA_NSEC_SHM);
567 		if (res) {
568 			tee_mm_free(mf->mm);
569 			mf->mm = NULL;
570 			goto out;
571 		}
572 	}
573 
574 	refcount_set(&mf->mapcount, 1);
575 out:
576 	cpu_spin_unlock_xrestore(&shm_lock, exceptions);
577 
578 	return res;
579 }
580 
581 static TEE_Result ffa_dec_map(struct mobj *mobj)
582 {
583 	struct mobj_ffa *mf = to_mobj_ffa(mobj);
584 	uint32_t exceptions = 0;
585 
586 	if (!refcount_dec(&mf->mapcount))
587 		return TEE_SUCCESS;
588 
589 	exceptions = cpu_spin_lock_xsave(&shm_lock);
590 	if (!refcount_val(&mf->mapcount))
591 		unmap_helper(mf);
592 	cpu_spin_unlock_xrestore(&shm_lock, exceptions);
593 
594 	return TEE_SUCCESS;
595 }
596 
597 static TEE_Result mapped_shm_init(void)
598 {
599 	vaddr_t pool_start = 0;
600 	vaddr_t pool_end = 0;
601 
602 	core_mmu_get_mem_by_type(MEM_AREA_SHM_VASPACE, &pool_start, &pool_end);
603 	if (!pool_start || !pool_end)
604 		panic("Can't find region for shmem pool");
605 
606 	if (!tee_mm_init(&tee_mm_shm, pool_start, pool_end, SMALL_PAGE_SHIFT,
607 			 TEE_MM_POOL_NO_FLAGS))
608 		panic("Could not create shmem pool");
609 
610 	DMSG("Shared memory address range: %#"PRIxVA", %#"PRIxVA,
611 	     pool_start, pool_end);
612 	return TEE_SUCCESS;
613 }
614 
615 /*
616  * Note: this variable is weak just to ease breaking its dependency chain
617  * when added to the unpaged area.
618  */
619 const struct mobj_ops mobj_ffa_ops __weak __rodata_unpaged("mobj_ffa_ops") = {
620 	.get_pa = ffa_get_pa,
621 	.get_phys_offs = ffa_get_phys_offs,
622 	.get_va = ffa_get_va,
623 	.get_cattr = ffa_get_cattr,
624 	.matches = ffa_matches,
625 	.free = ffa_inactivate,
626 	.get_cookie = ffa_get_cookie,
627 	.inc_map = ffa_inc_map,
628 	.dec_map = ffa_dec_map,
629 };
630 
631 preinit(mapped_shm_init);
632