xref: /openbmc/linux/drivers/char/tpm/tpm_ppi.c (revision e174b127)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2012-2014 Intel Corporation
4  *
5  * Authors:
6  * Xiaoyan Zhang <xiaoyan.zhang@intel.com>
7  * Jiang Liu <jiang.liu@linux.intel.com>
8  * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
9  *
10  * Maintained by: <tpmdd-devel@lists.sourceforge.net>
11  *
12  * This file contains implementation of the sysfs interface for PPI.
13  */
14 
15 
16 #include <linux/acpi.h>
17 #include "tpm.h"
18 
19 #define TPM_PPI_REVISION_ID_1	1
20 #define TPM_PPI_REVISION_ID_2	2
21 #define TPM_PPI_FN_VERSION	1
22 #define TPM_PPI_FN_SUBREQ	2
23 #define TPM_PPI_FN_GETREQ	3
24 #define TPM_PPI_FN_GETACT	4
25 #define TPM_PPI_FN_GETRSP	5
26 #define TPM_PPI_FN_SUBREQ2	7
27 #define TPM_PPI_FN_GETOPR	8
28 #define PPI_TPM_REQ_MAX		101 /* PPI 1.3 for TPM 2 */
29 #define PPI_VS_REQ_START	128
30 #define PPI_VS_REQ_END		255
31 
32 static const guid_t tpm_ppi_guid =
33 	GUID_INIT(0x3DDDFAA6, 0x361B, 0x4EB4,
34 		  0xA4, 0x24, 0x8D, 0x10, 0x08, 0x9D, 0x16, 0x53);
35 
tpm_ppi_req_has_parameter(u64 req)36 static bool tpm_ppi_req_has_parameter(u64 req)
37 {
38 	return req == 23;
39 }
40 
41 static inline union acpi_object *
tpm_eval_dsm(acpi_handle ppi_handle,int func,acpi_object_type type,union acpi_object * argv4,u64 rev)42 tpm_eval_dsm(acpi_handle ppi_handle, int func, acpi_object_type type,
43 	     union acpi_object *argv4, u64 rev)
44 {
45 	BUG_ON(!ppi_handle);
46 	return acpi_evaluate_dsm_typed(ppi_handle, &tpm_ppi_guid,
47 				       rev, func, argv4, type);
48 }
49 
tpm_show_ppi_version(struct device * dev,struct device_attribute * attr,char * buf)50 static ssize_t tpm_show_ppi_version(struct device *dev,
51 				    struct device_attribute *attr, char *buf)
52 {
53 	struct tpm_chip *chip = to_tpm_chip(dev);
54 
55 	return scnprintf(buf, PAGE_SIZE, "%s\n", chip->ppi_version);
56 }
57 
tpm_show_ppi_request(struct device * dev,struct device_attribute * attr,char * buf)58 static ssize_t tpm_show_ppi_request(struct device *dev,
59 				    struct device_attribute *attr, char *buf)
60 {
61 	ssize_t size = -EINVAL;
62 	union acpi_object *obj;
63 	struct tpm_chip *chip = to_tpm_chip(dev);
64 	u64 rev = TPM_PPI_REVISION_ID_2;
65 	u64 req;
66 
67 	if (strcmp(chip->ppi_version, "1.2") < 0)
68 		rev = TPM_PPI_REVISION_ID_1;
69 
70 	obj = tpm_eval_dsm(chip->acpi_dev_handle, TPM_PPI_FN_GETREQ,
71 			   ACPI_TYPE_PACKAGE, NULL, rev);
72 	if (!obj)
73 		return -ENXIO;
74 
75 	/*
76 	 * output.pointer should be of package type, including two integers.
77 	 * The first is function return code, 0 means success and 1 means
78 	 * error. The second is pending TPM operation requested by the OS, 0
79 	 * means none and >0 means operation value.
80 	 */
81 	if (obj->package.count == 3 &&
82 	    obj->package.elements[0].type == ACPI_TYPE_INTEGER &&
83 	    obj->package.elements[1].type == ACPI_TYPE_INTEGER &&
84 	    obj->package.elements[2].type == ACPI_TYPE_INTEGER) {
85 		if (obj->package.elements[0].integer.value)
86 			size = -EFAULT;
87 		else {
88 			req = obj->package.elements[1].integer.value;
89 			if (tpm_ppi_req_has_parameter(req))
90 				size = scnprintf(buf, PAGE_SIZE,
91 				    "%llu %llu\n", req,
92 				    obj->package.elements[2].integer.value);
93 			else
94 				size = scnprintf(buf, PAGE_SIZE,
95 						"%llu\n", req);
96 		}
97 	} else if (obj->package.count == 2 &&
98 	    obj->package.elements[0].type == ACPI_TYPE_INTEGER &&
99 	    obj->package.elements[1].type == ACPI_TYPE_INTEGER) {
100 		if (obj->package.elements[0].integer.value)
101 			size = -EFAULT;
102 		else
103 			size = scnprintf(buf, PAGE_SIZE, "%llu\n",
104 				 obj->package.elements[1].integer.value);
105 	}
106 
107 	ACPI_FREE(obj);
108 
109 	return size;
110 }
111 
tpm_store_ppi_request(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)112 static ssize_t tpm_store_ppi_request(struct device *dev,
113 				     struct device_attribute *attr,
114 				     const char *buf, size_t count)
115 {
116 	u32 req;
117 	u64 ret;
118 	int func = TPM_PPI_FN_SUBREQ;
119 	union acpi_object *obj, tmp[2];
120 	union acpi_object argv4 = ACPI_INIT_DSM_ARGV4(2, tmp);
121 	struct tpm_chip *chip = to_tpm_chip(dev);
122 	u64 rev = TPM_PPI_REVISION_ID_1;
123 
124 	/*
125 	 * the function to submit TPM operation request to pre-os environment
126 	 * is updated with function index from SUBREQ to SUBREQ2 since PPI
127 	 * version 1.1
128 	 */
129 	if (acpi_check_dsm(chip->acpi_dev_handle, &tpm_ppi_guid,
130 			   TPM_PPI_REVISION_ID_1, 1 << TPM_PPI_FN_SUBREQ2))
131 		func = TPM_PPI_FN_SUBREQ2;
132 
133 	/*
134 	 * PPI spec defines params[3].type as ACPI_TYPE_PACKAGE. Some BIOS
135 	 * accept buffer/string/integer type, but some BIOS accept buffer/
136 	 * string/package type. For PPI version 1.0 and 1.1, use buffer type
137 	 * for compatibility, and use package type since 1.2 according to spec.
138 	 */
139 	if (strcmp(chip->ppi_version, "1.3") == 0) {
140 		if (sscanf(buf, "%llu %llu", &tmp[0].integer.value,
141 			   &tmp[1].integer.value) != 2)
142 			goto ppi12;
143 		rev = TPM_PPI_REVISION_ID_2;
144 		tmp[0].type = ACPI_TYPE_INTEGER;
145 		tmp[1].type = ACPI_TYPE_INTEGER;
146 	} else if (strcmp(chip->ppi_version, "1.2") < 0) {
147 		if (sscanf(buf, "%d", &req) != 1)
148 			return -EINVAL;
149 		argv4.type = ACPI_TYPE_BUFFER;
150 		argv4.buffer.length = sizeof(req);
151 		argv4.buffer.pointer = (u8 *)&req;
152 	} else {
153 ppi12:
154 		argv4.package.count = 1;
155 		tmp[0].type = ACPI_TYPE_INTEGER;
156 		if (sscanf(buf, "%llu", &tmp[0].integer.value) != 1)
157 			return -EINVAL;
158 	}
159 
160 	obj = tpm_eval_dsm(chip->acpi_dev_handle, func, ACPI_TYPE_INTEGER,
161 			   &argv4, rev);
162 	if (!obj) {
163 		return -ENXIO;
164 	} else {
165 		ret = obj->integer.value;
166 		ACPI_FREE(obj);
167 	}
168 
169 	if (ret == 0)
170 		return (acpi_status)count;
171 
172 	return (ret == 1) ? -EPERM : -EFAULT;
173 }
174 
tpm_show_ppi_transition_action(struct device * dev,struct device_attribute * attr,char * buf)175 static ssize_t tpm_show_ppi_transition_action(struct device *dev,
176 					      struct device_attribute *attr,
177 					      char *buf)
178 {
179 	u32 ret;
180 	acpi_status status;
181 	union acpi_object *obj = NULL;
182 	union acpi_object tmp = {
183 		.buffer.type = ACPI_TYPE_BUFFER,
184 		.buffer.length = 0,
185 		.buffer.pointer = NULL
186 	};
187 	struct tpm_chip *chip = to_tpm_chip(dev);
188 
189 	static char *info[] = {
190 		"None",
191 		"Shutdown",
192 		"Reboot",
193 		"OS Vendor-specific",
194 		"Error",
195 	};
196 
197 	/*
198 	 * PPI spec defines params[3].type as empty package, but some platforms
199 	 * (e.g. Capella with PPI 1.0) need integer/string/buffer type, so for
200 	 * compatibility, define params[3].type as buffer, if PPI version < 1.2
201 	 */
202 	if (strcmp(chip->ppi_version, "1.2") < 0)
203 		obj = &tmp;
204 	obj = tpm_eval_dsm(chip->acpi_dev_handle, TPM_PPI_FN_GETACT,
205 			   ACPI_TYPE_INTEGER, obj, TPM_PPI_REVISION_ID_1);
206 	if (!obj) {
207 		return -ENXIO;
208 	} else {
209 		ret = obj->integer.value;
210 		ACPI_FREE(obj);
211 	}
212 
213 	if (ret < ARRAY_SIZE(info) - 1)
214 		status = scnprintf(buf, PAGE_SIZE, "%d: %s\n", ret, info[ret]);
215 	else
216 		status = scnprintf(buf, PAGE_SIZE, "%d: %s\n", ret,
217 				   info[ARRAY_SIZE(info)-1]);
218 	return status;
219 }
220 
tpm_show_ppi_response(struct device * dev,struct device_attribute * attr,char * buf)221 static ssize_t tpm_show_ppi_response(struct device *dev,
222 				     struct device_attribute *attr,
223 				     char *buf)
224 {
225 	acpi_status status = -EINVAL;
226 	union acpi_object *obj, *ret_obj;
227 	u64 req, res;
228 	struct tpm_chip *chip = to_tpm_chip(dev);
229 
230 	obj = tpm_eval_dsm(chip->acpi_dev_handle, TPM_PPI_FN_GETRSP,
231 			   ACPI_TYPE_PACKAGE, NULL, TPM_PPI_REVISION_ID_1);
232 	if (!obj)
233 		return -ENXIO;
234 
235 	/*
236 	 * parameter output.pointer should be of package type, including
237 	 * 3 integers. The first means function return code, the second means
238 	 * most recent TPM operation request, and the last means response to
239 	 * the most recent TPM operation request. Only if the first is 0, and
240 	 * the second integer is not 0, the response makes sense.
241 	 */
242 	ret_obj = obj->package.elements;
243 	if (obj->package.count < 3 ||
244 	    ret_obj[0].type != ACPI_TYPE_INTEGER ||
245 	    ret_obj[1].type != ACPI_TYPE_INTEGER ||
246 	    ret_obj[2].type != ACPI_TYPE_INTEGER)
247 		goto cleanup;
248 
249 	if (ret_obj[0].integer.value) {
250 		status = -EFAULT;
251 		goto cleanup;
252 	}
253 
254 	req = ret_obj[1].integer.value;
255 	res = ret_obj[2].integer.value;
256 	if (req) {
257 		if (res == 0)
258 			status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
259 					   "0: Success");
260 		else if (res == 0xFFFFFFF0)
261 			status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
262 					   "0xFFFFFFF0: User Abort");
263 		else if (res == 0xFFFFFFF1)
264 			status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
265 					   "0xFFFFFFF1: BIOS Failure");
266 		else if (res >= 1 && res <= 0x00000FFF)
267 			status = scnprintf(buf, PAGE_SIZE, "%llu %llu: %s\n",
268 					   req, res, "Corresponding TPM error");
269 		else
270 			status = scnprintf(buf, PAGE_SIZE, "%llu %llu: %s\n",
271 					   req, res, "Error");
272 	} else {
273 		status = scnprintf(buf, PAGE_SIZE, "%llu: %s\n",
274 				   req, "No Recent Request");
275 	}
276 
277 cleanup:
278 	ACPI_FREE(obj);
279 	return status;
280 }
281 
show_ppi_operations(acpi_handle dev_handle,char * buf,u32 start,u32 end)282 static ssize_t show_ppi_operations(acpi_handle dev_handle, char *buf, u32 start,
283 				   u32 end)
284 {
285 	int i;
286 	u32 ret;
287 	char *str = buf;
288 	union acpi_object *obj, tmp;
289 	union acpi_object argv = ACPI_INIT_DSM_ARGV4(1, &tmp);
290 
291 	static char *info[] = {
292 		"Not implemented",
293 		"BIOS only",
294 		"Blocked for OS by BIOS",
295 		"User required",
296 		"User not required",
297 	};
298 
299 	if (!acpi_check_dsm(dev_handle, &tpm_ppi_guid, TPM_PPI_REVISION_ID_1,
300 			    1 << TPM_PPI_FN_GETOPR))
301 		return -EPERM;
302 
303 	tmp.integer.type = ACPI_TYPE_INTEGER;
304 	for (i = start; i <= end; i++) {
305 		tmp.integer.value = i;
306 		obj = tpm_eval_dsm(dev_handle, TPM_PPI_FN_GETOPR,
307 				   ACPI_TYPE_INTEGER, &argv,
308 				   TPM_PPI_REVISION_ID_1);
309 		if (!obj) {
310 			return -ENOMEM;
311 		} else {
312 			ret = obj->integer.value;
313 			ACPI_FREE(obj);
314 		}
315 
316 		if (ret > 0 && ret < ARRAY_SIZE(info))
317 			str += scnprintf(str, PAGE_SIZE, "%d %d: %s\n",
318 					 i, ret, info[ret]);
319 	}
320 
321 	return str - buf;
322 }
323 
tpm_show_ppi_tcg_operations(struct device * dev,struct device_attribute * attr,char * buf)324 static ssize_t tpm_show_ppi_tcg_operations(struct device *dev,
325 					   struct device_attribute *attr,
326 					   char *buf)
327 {
328 	struct tpm_chip *chip = to_tpm_chip(dev);
329 
330 	return show_ppi_operations(chip->acpi_dev_handle, buf, 0,
331 				   PPI_TPM_REQ_MAX);
332 }
333 
tpm_show_ppi_vs_operations(struct device * dev,struct device_attribute * attr,char * buf)334 static ssize_t tpm_show_ppi_vs_operations(struct device *dev,
335 					  struct device_attribute *attr,
336 					  char *buf)
337 {
338 	struct tpm_chip *chip = to_tpm_chip(dev);
339 
340 	return show_ppi_operations(chip->acpi_dev_handle, buf, PPI_VS_REQ_START,
341 				   PPI_VS_REQ_END);
342 }
343 
344 static DEVICE_ATTR(version, S_IRUGO, tpm_show_ppi_version, NULL);
345 static DEVICE_ATTR(request, S_IRUGO | S_IWUSR | S_IWGRP,
346 		   tpm_show_ppi_request, tpm_store_ppi_request);
347 static DEVICE_ATTR(transition_action, S_IRUGO,
348 		   tpm_show_ppi_transition_action, NULL);
349 static DEVICE_ATTR(response, S_IRUGO, tpm_show_ppi_response, NULL);
350 static DEVICE_ATTR(tcg_operations, S_IRUGO, tpm_show_ppi_tcg_operations, NULL);
351 static DEVICE_ATTR(vs_operations, S_IRUGO, tpm_show_ppi_vs_operations, NULL);
352 
353 static struct attribute *ppi_attrs[] = {
354 	&dev_attr_version.attr,
355 	&dev_attr_request.attr,
356 	&dev_attr_transition_action.attr,
357 	&dev_attr_response.attr,
358 	&dev_attr_tcg_operations.attr,
359 	&dev_attr_vs_operations.attr, NULL,
360 };
361 static const struct attribute_group ppi_attr_grp = {
362 	.name = "ppi",
363 	.attrs = ppi_attrs
364 };
365 
tpm_add_ppi(struct tpm_chip * chip)366 void tpm_add_ppi(struct tpm_chip *chip)
367 {
368 	union acpi_object *obj;
369 
370 	if (!chip->acpi_dev_handle)
371 		return;
372 
373 	if (!acpi_check_dsm(chip->acpi_dev_handle, &tpm_ppi_guid,
374 			    TPM_PPI_REVISION_ID_1, 1 << TPM_PPI_FN_VERSION))
375 		return;
376 
377 	/* Cache PPI version string. */
378 	obj = acpi_evaluate_dsm_typed(chip->acpi_dev_handle, &tpm_ppi_guid,
379 				      TPM_PPI_REVISION_ID_1,
380 				      TPM_PPI_FN_VERSION,
381 				      NULL, ACPI_TYPE_STRING);
382 	if (obj) {
383 		strscpy(chip->ppi_version, obj->string.pointer,
384 			sizeof(chip->ppi_version));
385 		ACPI_FREE(obj);
386 	}
387 
388 	chip->groups[chip->groups_cnt++] = &ppi_attr_grp;
389 }
390