1// SPDX-License-Identifier: MIT
2/*
3 * AMD Trusted Execution Environment (TEE) interface
4 *
5 * Author: Rijo Thomas <Rijo-john.Thomas@amd.com>
6 * Author: Devaraj Rangasamy <Devaraj.Rangasamy@amd.com>
7 *
8 * Copyright (C) 2019,2021 Advanced Micro Devices, Inc.
9 */
10
11#include <linux/bitfield.h>
12#include <linux/types.h>
13#include <linux/mutex.h>
14#include <linux/delay.h>
15#include <linux/slab.h>
16#include <linux/gfp.h>
17#include <linux/psp.h>
18#include <linux/psp-tee.h>
19
20#include "psp-dev.h"
21#include "tee-dev.h"
22
23static bool psp_dead;
24
25static int tee_alloc_ring(struct psp_tee_device *tee, int ring_size)
26{
27 struct ring_buf_manager *rb_mgr = &tee->rb_mgr;
28 void *start_addr;
29
30 if (!ring_size)
31 return -EINVAL;
32
33 /* We need actual physical address instead of DMA address, since
34 * Trusted OS running on AMD Secure Processor will map this region
35 */
36 start_addr = (void *)__get_free_pages(GFP_KERNEL, get_order(ring_size));
37 if (!start_addr)
38 return -ENOMEM;
39
40 memset(start_addr, 0x0, ring_size);
41 rb_mgr->ring_start = start_addr;
42 rb_mgr->ring_size = ring_size;
43 rb_mgr->ring_pa = __psp_pa(start_addr);
44 mutex_init(&rb_mgr->mutex);
45
46 return 0;
47}
48
49static void tee_free_ring(struct psp_tee_device *tee)
50{
51 struct ring_buf_manager *rb_mgr = &tee->rb_mgr;
52
53 if (!rb_mgr->ring_start)
54 return;
55
56 free_pages(addr: (unsigned long)rb_mgr->ring_start,
57 order: get_order(size: rb_mgr->ring_size));
58
59 rb_mgr->ring_start = NULL;
60 rb_mgr->ring_size = 0;
61 rb_mgr->ring_pa = 0;
62 mutex_destroy(lock: &rb_mgr->mutex);
63}
64
65static
66struct tee_init_ring_cmd *tee_alloc_cmd_buffer(struct psp_tee_device *tee)
67{
68 struct tee_init_ring_cmd *cmd;
69
70 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
71 if (!cmd)
72 return NULL;
73
74 cmd->hi_addr = upper_32_bits(tee->rb_mgr.ring_pa);
75 cmd->low_addr = lower_32_bits(tee->rb_mgr.ring_pa);
76 cmd->size = tee->rb_mgr.ring_size;
77
78 dev_dbg(tee->dev, "tee: ring address: high = 0x%x low = 0x%x size = %u\n",
79 cmd->hi_addr, cmd->low_addr, cmd->size);
80
81 return cmd;
82}
83
84static inline void tee_free_cmd_buffer(struct tee_init_ring_cmd *cmd)
85{
86 kfree(objp: cmd);
87}
88
89static int tee_init_ring(struct psp_tee_device *tee)
90{
91 int ring_size = MAX_RING_BUFFER_ENTRIES * sizeof(struct tee_ring_cmd);
92 struct tee_init_ring_cmd *cmd;
93 unsigned int reg;
94 int ret;
95
96 BUILD_BUG_ON(sizeof(struct tee_ring_cmd) != 1024);
97
98 ret = tee_alloc_ring(tee, ring_size);
99 if (ret) {
100 dev_err(tee->dev, "tee: ring allocation failed %d\n", ret);
101 return ret;
102 }
103
104 tee->rb_mgr.wptr = 0;
105
106 cmd = tee_alloc_cmd_buffer(tee);
107 if (!cmd) {
108 tee_free_ring(tee);
109 return -ENOMEM;
110 }
111
112 /* Send command buffer details to Trusted OS by writing to
113 * CPU-PSP message registers
114 */
115 ret = psp_mailbox_command(psp: tee->psp, cmd: PSP_CMD_TEE_RING_INIT, cmdbuff: cmd,
116 TEE_DEFAULT_CMD_TIMEOUT, cmdresp: &reg);
117 if (ret) {
118 dev_err(tee->dev, "tee: ring init command timed out, disabling TEE support\n");
119 tee_free_ring(tee);
120 psp_dead = true;
121 goto free_buf;
122 }
123
124 if (FIELD_GET(PSP_CMDRESP_STS, reg)) {
125 dev_err(tee->dev, "tee: ring init command failed (%#010lx)\n",
126 FIELD_GET(PSP_CMDRESP_STS, reg));
127 tee_free_ring(tee);
128 ret = -EIO;
129 }
130
131free_buf:
132 tee_free_cmd_buffer(cmd);
133
134 return ret;
135}
136
137static void tee_destroy_ring(struct psp_tee_device *tee)
138{
139 unsigned int reg;
140 int ret;
141
142 if (!tee->rb_mgr.ring_start)
143 return;
144
145 if (psp_dead)
146 goto free_ring;
147
148 ret = psp_mailbox_command(psp: tee->psp, cmd: PSP_CMD_TEE_RING_DESTROY, NULL,
149 TEE_DEFAULT_CMD_TIMEOUT, cmdresp: &reg);
150 if (ret) {
151 dev_err(tee->dev, "tee: ring destroy command timed out, disabling TEE support\n");
152 psp_dead = true;
153 } else if (FIELD_GET(PSP_CMDRESP_STS, reg)) {
154 dev_err(tee->dev, "tee: ring destroy command failed (%#010lx)\n",
155 FIELD_GET(PSP_CMDRESP_STS, reg));
156 }
157
158free_ring:
159 tee_free_ring(tee);
160}
161
162int tee_dev_init(struct psp_device *psp)
163{
164 struct device *dev = psp->dev;
165 struct psp_tee_device *tee;
166 int ret;
167
168 ret = -ENOMEM;
169 tee = devm_kzalloc(dev, size: sizeof(*tee), GFP_KERNEL);
170 if (!tee)
171 goto e_err;
172
173 psp->tee_data = tee;
174
175 tee->dev = dev;
176 tee->psp = psp;
177
178 tee->io_regs = psp->io_regs;
179
180 tee->vdata = (struct tee_vdata *)psp->vdata->tee;
181 if (!tee->vdata) {
182 ret = -ENODEV;
183 dev_err(dev, "tee: missing driver data\n");
184 goto e_err;
185 }
186
187 ret = tee_init_ring(tee);
188 if (ret) {
189 dev_err(dev, "tee: failed to init ring buffer\n");
190 goto e_err;
191 }
192
193 dev_notice(dev, "tee enabled\n");
194
195 return 0;
196
197e_err:
198 psp->tee_data = NULL;
199
200 dev_notice(dev, "tee initialization failed\n");
201
202 return ret;
203}
204
205void tee_dev_destroy(struct psp_device *psp)
206{
207 struct psp_tee_device *tee = psp->tee_data;
208
209 if (!tee)
210 return;
211
212 tee_destroy_ring(tee);
213}
214
215static int tee_submit_cmd(struct psp_tee_device *tee, enum tee_cmd_id cmd_id,
216 void *buf, size_t len, struct tee_ring_cmd **resp)
217{
218 struct tee_ring_cmd *cmd;
219 int nloop = 1000, ret = 0;
220 u32 rptr;
221
222 *resp = NULL;
223
224 mutex_lock(&tee->rb_mgr.mutex);
225
226 /* Loop until empty entry found in ring buffer */
227 do {
228 /* Get pointer to ring buffer command entry */
229 cmd = (struct tee_ring_cmd *)
230 (tee->rb_mgr.ring_start + tee->rb_mgr.wptr);
231
232 rptr = ioread32(tee->io_regs + tee->vdata->ring_rptr_reg);
233
234 /* Check if ring buffer is full or command entry is waiting
235 * for response from TEE
236 */
237 if (!(tee->rb_mgr.wptr + sizeof(struct tee_ring_cmd) == rptr ||
238 cmd->flag == CMD_WAITING_FOR_RESPONSE))
239 break;
240
241 dev_dbg(tee->dev, "tee: ring buffer full. rptr = %u wptr = %u\n",
242 rptr, tee->rb_mgr.wptr);
243
244 /* Wait if ring buffer is full or TEE is processing data */
245 mutex_unlock(lock: &tee->rb_mgr.mutex);
246 schedule_timeout_interruptible(timeout: msecs_to_jiffies(m: 10));
247 mutex_lock(&tee->rb_mgr.mutex);
248
249 } while (--nloop);
250
251 if (!nloop &&
252 (tee->rb_mgr.wptr + sizeof(struct tee_ring_cmd) == rptr ||
253 cmd->flag == CMD_WAITING_FOR_RESPONSE)) {
254 dev_err(tee->dev, "tee: ring buffer full. rptr = %u wptr = %u response flag %u\n",
255 rptr, tee->rb_mgr.wptr, cmd->flag);
256 ret = -EBUSY;
257 goto unlock;
258 }
259
260 /* Do not submit command if PSP got disabled while processing any
261 * command in another thread
262 */
263 if (psp_dead) {
264 ret = -EBUSY;
265 goto unlock;
266 }
267
268 /* Write command data into ring buffer */
269 cmd->cmd_id = cmd_id;
270 cmd->cmd_state = TEE_CMD_STATE_INIT;
271 memset(&cmd->buf[0], 0, sizeof(cmd->buf));
272 memcpy(&cmd->buf[0], buf, len);
273
274 /* Indicate driver is waiting for response */
275 cmd->flag = CMD_WAITING_FOR_RESPONSE;
276
277 /* Update local copy of write pointer */
278 tee->rb_mgr.wptr += sizeof(struct tee_ring_cmd);
279 if (tee->rb_mgr.wptr >= tee->rb_mgr.ring_size)
280 tee->rb_mgr.wptr = 0;
281
282 /* Trigger interrupt to Trusted OS */
283 iowrite32(tee->rb_mgr.wptr, tee->io_regs + tee->vdata->ring_wptr_reg);
284
285 /* The response is provided by Trusted OS in same
286 * location as submitted data entry within ring buffer.
287 */
288 *resp = cmd;
289
290unlock:
291 mutex_unlock(lock: &tee->rb_mgr.mutex);
292
293 return ret;
294}
295
296static int tee_wait_cmd_completion(struct psp_tee_device *tee,
297 struct tee_ring_cmd *resp,
298 unsigned int timeout)
299{
300 /* ~1ms sleep per loop => nloop = timeout * 1000 */
301 int nloop = timeout * 1000;
302
303 while (--nloop) {
304 if (resp->cmd_state == TEE_CMD_STATE_COMPLETED)
305 return 0;
306
307 usleep_range(min: 1000, max: 1100);
308 }
309
310 dev_err(tee->dev, "tee: command 0x%x timed out, disabling PSP\n",
311 resp->cmd_id);
312
313 psp_dead = true;
314
315 return -ETIMEDOUT;
316}
317
318int psp_tee_process_cmd(enum tee_cmd_id cmd_id, void *buf, size_t len,
319 u32 *status)
320{
321 struct psp_device *psp = psp_get_master_device();
322 struct psp_tee_device *tee;
323 struct tee_ring_cmd *resp;
324 int ret;
325
326 if (!buf || !status || !len || len > sizeof(resp->buf))
327 return -EINVAL;
328
329 *status = 0;
330
331 if (!psp || !psp->tee_data)
332 return -ENODEV;
333
334 if (psp_dead)
335 return -EBUSY;
336
337 tee = psp->tee_data;
338
339 ret = tee_submit_cmd(tee, cmd_id, buf, len, resp: &resp);
340 if (ret)
341 return ret;
342
343 ret = tee_wait_cmd_completion(tee, resp, TEE_DEFAULT_RING_TIMEOUT);
344 if (ret) {
345 resp->flag = CMD_RESPONSE_TIMEDOUT;
346 return ret;
347 }
348
349 memcpy(buf, &resp->buf[0], len);
350 *status = resp->status;
351
352 resp->flag = CMD_RESPONSE_COPIED;
353
354 return 0;
355}
356EXPORT_SYMBOL(psp_tee_process_cmd);
357
358int psp_check_tee_status(void)
359{
360 struct psp_device *psp = psp_get_master_device();
361
362 if (!psp || !psp->tee_data)
363 return -ENODEV;
364
365 return 0;
366}
367EXPORT_SYMBOL(psp_check_tee_status);
368

source code of linux/drivers/crypto/ccp/tee-dev.c