xref: /openbmc/linux/drivers/tee/amdtee/shm_pool.c (revision fbb6b31a)
1 // SPDX-License-Identifier: MIT
2 /*
3  * Copyright 2019 Advanced Micro Devices, Inc.
4  */
5 
6 #include <linux/slab.h>
7 #include <linux/tee_drv.h>
8 #include <linux/psp-sev.h>
9 #include "amdtee_private.h"
10 
11 static int pool_op_alloc(struct tee_shm_pool *pool, struct tee_shm *shm,
12 			 size_t size, size_t align)
13 {
14 	unsigned int order = get_order(size);
15 	unsigned long va;
16 	int rc;
17 
18 	/*
19 	 * Ignore alignment since this is already going to be page aligned
20 	 * and there's no need for any larger alignment.
21 	 */
22 	va = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
23 	if (!va)
24 		return -ENOMEM;
25 
26 	shm->kaddr = (void *)va;
27 	shm->paddr = __psp_pa((void *)va);
28 	shm->size = PAGE_SIZE << order;
29 
30 	/* Map the allocated memory in to TEE */
31 	rc = amdtee_map_shmem(shm);
32 	if (rc) {
33 		free_pages(va, order);
34 		shm->kaddr = NULL;
35 		return rc;
36 	}
37 
38 	return 0;
39 }
40 
41 static void pool_op_free(struct tee_shm_pool *pool, struct tee_shm *shm)
42 {
43 	/* Unmap the shared memory from TEE */
44 	amdtee_unmap_shmem(shm);
45 	free_pages((unsigned long)shm->kaddr, get_order(shm->size));
46 	shm->kaddr = NULL;
47 }
48 
49 static void pool_op_destroy_pool(struct tee_shm_pool *pool)
50 {
51 	kfree(pool);
52 }
53 
54 static const struct tee_shm_pool_ops pool_ops = {
55 	.alloc = pool_op_alloc,
56 	.free = pool_op_free,
57 	.destroy_pool = pool_op_destroy_pool,
58 };
59 
60 struct tee_shm_pool *amdtee_config_shm(void)
61 {
62 	struct tee_shm_pool *pool = kzalloc(sizeof(*pool), GFP_KERNEL);
63 
64 	if (!pool)
65 		return ERR_PTR(-ENOMEM);
66 
67 	pool->ops = &pool_ops;
68 
69 	return pool;
70 }
71