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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
4 */
5
6#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
7
8#include <linux/firmware/qcom/qcom_scm.h>
9#include <linux/mm.h>
10
11#include "qcomtee.h"
12
13/**
14 * DOC: Memory and Mapping Objects
15 *
16 * QTEE uses memory objects for memory sharing with Linux.
17 * A memory object can be a standard dma_buf or a contiguous memory range,
18 * e.g., tee_shm. A memory object should support one operation: map. When
19 * invoked by QTEE, a mapping object is generated. A mapping object supports
20 * one operation: unmap.
21 *
22 * (1) To map a memory object, QTEE invokes the primordial object with
23 * %QCOMTEE_OBJECT_OP_MAP_REGION operation; see
24 * qcomtee_primordial_obj_dispatch().
25 * (2) To unmap a memory object, QTEE releases the mapping object which
26 * calls qcomtee_mem_object_release().
27 *
28 * The map operation is implemented in the primordial object as a privileged
29 * operation instead of qcomtee_mem_object_dispatch(). Otherwise, on
30 * platforms without shm_bridge, a user can trick QTEE into writing to the
31 * kernel memory by passing a user object as a memory object and returning a
32 * random physical address as the result of the mapping request.
33 */
34
35struct qcomtee_mem_object {
36 struct qcomtee_object object;
37 struct tee_shm *shm;
38 /* QTEE requires these felids to be page aligned. */
39 phys_addr_t paddr; /* Physical address of range. */
40 size_t size; /* Size of the range. */
41};
42
43#define to_qcomtee_mem_object(o) \
44 container_of((o), struct qcomtee_mem_object, object)
45
46static struct qcomtee_object_operations qcomtee_mem_object_ops;
47
48/* Is it a memory object using tee_shm? */
49int is_qcomtee_memobj_object(struct qcomtee_object *object)
50{
51 return object != NULL_QCOMTEE_OBJECT &&
52 typeof_qcomtee_object(object) == QCOMTEE_OBJECT_TYPE_CB &&
53 object->ops == &qcomtee_mem_object_ops;
54}
55
56static int qcomtee_mem_object_dispatch(struct qcomtee_object_invoke_ctx *oic,
57 struct qcomtee_object *object, u32 op,
58 struct qcomtee_arg *args)
59{
60 return -EINVAL;
61}
62
63static void qcomtee_mem_object_release(struct qcomtee_object *object)
64{
65 struct qcomtee_mem_object *mem_object = to_qcomtee_mem_object(object);
66
67 /* Matching get is in qcomtee_memobj_param_to_object(). */
68 tee_shm_put(mem_object->shm);
69 kfree(mem_object);
70}
71
72static struct qcomtee_object_operations qcomtee_mem_object_ops = {
73 .release = qcomtee_mem_object_release,
74 .dispatch = qcomtee_mem_object_dispatch,
75};
76
77/**
78 * qcomtee_memobj_param_to_object() - OBJREF parameter to &struct qcomtee_object.
79 * @object: object returned.
80 * @param: TEE parameter.
81 * @ctx: context in which the conversion should happen.
82 *
83 * @param is an OBJREF with %QCOMTEE_OBJREF_FLAG_MEM flags.
84 *
85 * Return: On success return 0 or <0 on failure.
86 */
87int qcomtee_memobj_param_to_object(struct qcomtee_object **object,
88 struct tee_param *param,
89 struct tee_context *ctx)
90{
91 struct qcomtee_mem_object *mem_object __free(kfree) = NULL;
92 struct tee_shm *shm;
93 int err;
94
95 mem_object = kzalloc(sizeof(*mem_object), GFP_KERNEL);
96 if (!mem_object)
97 return -ENOMEM;
98
99 shm = tee_shm_get_from_id(ctx, param->u.objref.id);
100 if (IS_ERR(shm))
101 return PTR_ERR(shm);
102
103 /* mem-object wrapping the memref. */
104 err = qcomtee_object_user_init(&mem_object->object,
105 QCOMTEE_OBJECT_TYPE_CB,
106 &qcomtee_mem_object_ops, "tee-shm-%d",
107 shm->id);
108 if (err) {
109 tee_shm_put(shm);
110
111 return err;
112 }
113
114 mem_object->paddr = shm->paddr;
115 mem_object->size = shm->size;
116 mem_object->shm = shm;
117
118 *object = &no_free_ptr(mem_object)->object;
119
120 return 0;
121}
122
123/* Reverse what qcomtee_memobj_param_to_object() does. */
124int qcomtee_memobj_param_from_object(struct tee_param *param,
125 struct qcomtee_object *object,
126 struct tee_context *ctx)
127{
128 struct qcomtee_mem_object *mem_object;
129
130 mem_object = to_qcomtee_mem_object(object);
131 /* Sure if the memobj is in a same context it is originated from. */
132 if (mem_object->shm->ctx != ctx)
133 return -EINVAL;
134
135 param->u.objref.id = mem_object->shm->id;
136 param->u.objref.flags = QCOMTEE_OBJREF_FLAG_MEM;
137
138 /* Passing shm->id to userspace; drop the reference. */
139 qcomtee_object_put(object);
140
141 return 0;
142}
143
144/**
145 * qcomtee_mem_object_map() - Map a memory object.
146 * @object: memory object.
147 * @map_object: created mapping object.
148 * @mem_paddr: physical address of the memory.
149 * @mem_size: size of the memory.
150 * @perms: QTEE access permissions.
151 *
152 * Return: On success return 0 or <0 on failure.
153 */
154int qcomtee_mem_object_map(struct qcomtee_object *object,
155 struct qcomtee_object **map_object, u64 *mem_paddr,
156 u64 *mem_size, u32 *perms)
157{
158 struct qcomtee_mem_object *mem_object = to_qcomtee_mem_object(object);
159
160 /* Reuses the memory object as a mapping object by re-sharing it. */
161 qcomtee_object_get(&mem_object->object);
162
163 *map_object = &mem_object->object;
164 *mem_paddr = mem_object->paddr;
165 *mem_size = mem_object->size;
166 *perms = QCOM_SCM_PERM_RW;
167
168 return 0;
169}