tpm_ppi.c

  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
 32static const guid_t tpm_ppi_guid =
 33	GUID_INIT(0x3DDDFAA6, 0x361B, 0x4EB4,
 34		  0xA4, 0x24, 0x8D, 0x10, 0x08, 0x9D, 0x16, 0x53);
 35
 36static const char * const tpm_ppi_info[] = {
 37	"Not implemented",
 38	"BIOS only",
 39	"Blocked for OS by system firmware",
 40	"User required",
 41	"User not required",
 42};
 43
 44/* A spinlock to protect access to the cache from concurrent reads */
 45static DEFINE_MUTEX(tpm_ppi_lock);
 46
 47static u32 ppi_operations_cache[PPI_VS_REQ_END + 1];
 48static bool ppi_cache_populated;
 49
 50static bool tpm_ppi_req_has_parameter(u64 req)
 51{
 52	return req == 23;
 53}
 54
 55static inline union acpi_object *
 56tpm_eval_dsm(acpi_handle ppi_handle, int func, acpi_object_type type,
 57	     union acpi_object *argv4, u64 rev)
 58{
 59	BUG_ON(!ppi_handle);
 60	return acpi_evaluate_dsm_typed(ppi_handle, &tpm_ppi_guid,
 61				       rev, func, argv4, type);
 62}
 63
 64static ssize_t tpm_show_ppi_version(struct device *dev,
 65				    struct device_attribute *attr, char *buf)
 66{
 67	struct tpm_chip *chip = to_tpm_chip(dev);
 68
 69	return sysfs_emit(buf, "%s\n", chip->ppi_version);
 70}
 71
 72static ssize_t tpm_show_ppi_request(struct device *dev,
 73				    struct device_attribute *attr, char *buf)
 74{
 75	ssize_t size = -EINVAL;
 76	union acpi_object *obj;
 77	struct tpm_chip *chip = to_tpm_chip(dev);
 78	u64 rev = TPM_PPI_REVISION_ID_2;
 79	u64 req;
 80
 81	if (strcmp(chip->ppi_version, "1.2") < 0)
 82		rev = TPM_PPI_REVISION_ID_1;
 83
 84	obj = tpm_eval_dsm(chip->acpi_dev_handle, TPM_PPI_FN_GETREQ,
 85			   ACPI_TYPE_PACKAGE, NULL, rev);
 86	if (!obj)
 87		return -ENXIO;
 88
 89	/*
 90	 * output.pointer should be of package type, including two integers.
 91	 * The first is function return code, 0 means success and 1 means
 92	 * error. The second is pending TPM operation requested by the OS, 0
 93	 * means none and >0 means operation value.
 94	 */
 95	if (obj->package.count == 3 &&
 96	    obj->package.elements[0].type == ACPI_TYPE_INTEGER &&
 97	    obj->package.elements[1].type == ACPI_TYPE_INTEGER &&
 98	    obj->package.elements[2].type == ACPI_TYPE_INTEGER) {
 99		if (obj->package.elements[0].integer.value)
100			size = -EFAULT;
101		else {
102			req = obj->package.elements[1].integer.value;
103			if (tpm_ppi_req_has_parameter(req))
104				size = sysfs_emit(buf, "%llu %llu\n", req,
105						  obj->package.elements[2].integer.value);
106			else
107				size = sysfs_emit(buf, "%llu\n", req);
108		}
109	} else if (obj->package.count == 2 &&
110	    obj->package.elements[0].type == ACPI_TYPE_INTEGER &&
111	    obj->package.elements[1].type == ACPI_TYPE_INTEGER) {
112		if (obj->package.elements[0].integer.value)
113			size = -EFAULT;
114		else
115			size = sysfs_emit(buf, "%llu\n",
116					  obj->package.elements[1].integer.value);
117	}
118
119	ACPI_FREE(obj);
120
121	return size;
122}
123
124static ssize_t tpm_store_ppi_request(struct device *dev,
125				     struct device_attribute *attr,
126				     const char *buf, size_t count)
127{
128	u32 req;
129	u64 ret;
130	int func = TPM_PPI_FN_SUBREQ;
131	union acpi_object *obj, tmp[2];
132	union acpi_object argv4 = ACPI_INIT_DSM_ARGV4(2, tmp);
133	struct tpm_chip *chip = to_tpm_chip(dev);
134	u64 rev = TPM_PPI_REVISION_ID_1;
135
136	/*
137	 * the function to submit TPM operation request to pre-os environment
138	 * is updated with function index from SUBREQ to SUBREQ2 since PPI
139	 * version 1.1
140	 */
141	if (acpi_check_dsm(chip->acpi_dev_handle, &tpm_ppi_guid,
142			   TPM_PPI_REVISION_ID_1, 1 << TPM_PPI_FN_SUBREQ2))
143		func = TPM_PPI_FN_SUBREQ2;
144
145	/*
146	 * PPI spec defines params[3].type as ACPI_TYPE_PACKAGE. Some BIOS
147	 * accept buffer/string/integer type, but some BIOS accept buffer/
148	 * string/package type. For PPI version 1.0 and 1.1, use buffer type
149	 * for compatibility, and use package type since 1.2 according to spec.
150	 */
151	if (strcmp(chip->ppi_version, "1.3") == 0) {
152		if (sscanf(buf, "%llu %llu", &tmp[0].integer.value,
153			   &tmp[1].integer.value) != 2)
154			goto ppi12;
155		rev = TPM_PPI_REVISION_ID_2;
156		tmp[0].type = ACPI_TYPE_INTEGER;
157		tmp[1].type = ACPI_TYPE_INTEGER;
158	} else if (strcmp(chip->ppi_version, "1.2") < 0) {
159		if (sscanf(buf, "%d", &req) != 1)
160			return -EINVAL;
161		argv4.type = ACPI_TYPE_BUFFER;
162		argv4.buffer.length = sizeof(req);
163		argv4.buffer.pointer = (u8 *)&req;
164	} else {
165ppi12:
166		argv4.package.count = 1;
167		tmp[0].type = ACPI_TYPE_INTEGER;
168		if (sscanf(buf, "%llu", &tmp[0].integer.value) != 1)
169			return -EINVAL;
170	}
171
172	obj = tpm_eval_dsm(chip->acpi_dev_handle, func, ACPI_TYPE_INTEGER,
173			   &argv4, rev);
174	if (!obj) {
175		return -ENXIO;
176	} else {
177		ret = obj->integer.value;
178		ACPI_FREE(obj);
179	}
180
181	if (ret == 0)
182		return (acpi_status)count;
183
184	return (ret == 1) ? -EPERM : -EFAULT;
185}
186
187static ssize_t tpm_show_ppi_transition_action(struct device *dev,
188					      struct device_attribute *attr,
189					      char *buf)
190{
191	u32 ret;
192	acpi_status status;
193	union acpi_object *obj = NULL;
194	union acpi_object tmp = {
195		.buffer.type = ACPI_TYPE_BUFFER,
196		.buffer.length = 0,
197		.buffer.pointer = NULL
198	};
199	struct tpm_chip *chip = to_tpm_chip(dev);
200
201	static char *info[] = {
202		"None",
203		"Shutdown",
204		"Reboot",
205		"OS Vendor-specific",
206		"Error",
207	};
208
209	/*
210	 * PPI spec defines params[3].type as empty package, but some platforms
211	 * (e.g. Capella with PPI 1.0) need integer/string/buffer type, so for
212	 * compatibility, define params[3].type as buffer, if PPI version < 1.2
213	 */
214	if (strcmp(chip->ppi_version, "1.2") < 0)
215		obj = &tmp;
216	obj = tpm_eval_dsm(chip->acpi_dev_handle, TPM_PPI_FN_GETACT,
217			   ACPI_TYPE_INTEGER, obj, TPM_PPI_REVISION_ID_1);
218	if (!obj) {
219		return -ENXIO;
220	} else {
221		ret = obj->integer.value;
222		ACPI_FREE(obj);
223	}
224
225	if (ret < ARRAY_SIZE(info) - 1)
226		status = sysfs_emit(buf, "%d: %s\n", ret, info[ret]);
227	else
228		status = sysfs_emit(buf, "%d: %s\n", ret,
229				    info[ARRAY_SIZE(info) - 1]);
230	return status;
231}
232
233static ssize_t tpm_show_ppi_response(struct device *dev,
234				     struct device_attribute *attr,
235				     char *buf)
236{
237	acpi_status status = -EINVAL;
238	union acpi_object *obj, *ret_obj;
239	u64 req, res;
240	struct tpm_chip *chip = to_tpm_chip(dev);
241
242	obj = tpm_eval_dsm(chip->acpi_dev_handle, TPM_PPI_FN_GETRSP,
243			   ACPI_TYPE_PACKAGE, NULL, TPM_PPI_REVISION_ID_1);
244	if (!obj)
245		return -ENXIO;
246
247	/*
248	 * parameter output.pointer should be of package type, including
249	 * 3 integers. The first means function return code, the second means
250	 * most recent TPM operation request, and the last means response to
251	 * the most recent TPM operation request. Only if the first is 0, and
252	 * the second integer is not 0, the response makes sense.
253	 */
254	ret_obj = obj->package.elements;
255	if (obj->package.count < 3 ||
256	    ret_obj[0].type != ACPI_TYPE_INTEGER ||
257	    ret_obj[1].type != ACPI_TYPE_INTEGER ||
258	    ret_obj[2].type != ACPI_TYPE_INTEGER)
259		goto cleanup;
260
261	if (ret_obj[0].integer.value) {
262		status = -EFAULT;
263		goto cleanup;
264	}
265
266	req = ret_obj[1].integer.value;
267	res = ret_obj[2].integer.value;
268	if (req) {
269		if (res == 0)
270			status = sysfs_emit(buf, "%llu %s\n", req,
271					    "0: Success");
272		else if (res == 0xFFFFFFF0)
273			status = sysfs_emit(buf, "%llu %s\n", req,
274					    "0xFFFFFFF0: User Abort");
275		else if (res == 0xFFFFFFF1)
276			status = sysfs_emit(buf, "%llu %s\n", req,
277					    "0xFFFFFFF1: BIOS Failure");
278		else if (res >= 1 && res <= 0x00000FFF)
279			status = sysfs_emit(buf, "%llu %llu: %s\n",
280					    req, res, "Corresponding TPM error");
281		else
282			status = sysfs_emit(buf, "%llu %llu: %s\n",
283					    req, res, "Error");
284	} else {
285		status = sysfs_emit(buf, "%llu: %s\n",
286				    req, "No Recent Request");
287	}
288
289cleanup:
290	ACPI_FREE(obj);
291	return status;
292}
293
294static ssize_t cache_ppi_operations(acpi_handle dev_handle, char *buf)
295{
296	int i;
297	u32 ret;
298	int len = 0;
299	union acpi_object *obj, tmp;
300	union acpi_object argv = ACPI_INIT_DSM_ARGV4(1, &tmp);
301
302	if (!acpi_check_dsm(dev_handle, &tpm_ppi_guid, TPM_PPI_REVISION_ID_1,
303			    1 << TPM_PPI_FN_GETOPR))
304		return -EPERM;
305
306	tmp.integer.type = ACPI_TYPE_INTEGER;
307	for (i = 0; i <= PPI_VS_REQ_END; i++) {
308		tmp.integer.value = i;
309		obj = tpm_eval_dsm(dev_handle, TPM_PPI_FN_GETOPR,
310				   ACPI_TYPE_INTEGER, &argv,
311				   TPM_PPI_REVISION_ID_1);
312		if (!obj)
313			return -ENOMEM;
314
315		ret = obj->integer.value;
316		ppi_operations_cache[i] = ret;
317		ACPI_FREE(obj);
318	}
319
320	return len;
321}
322
323static ssize_t tpm_show_ppi_tcg_operations(struct device *dev,
324					   struct device_attribute *attr,
325					   char *buf)
326{
327	struct tpm_chip *chip = to_tpm_chip(dev);
328	ssize_t len = 0;
329	u32 ret;
330	int i;
331
332	mutex_lock(&tpm_ppi_lock);
333	if (!ppi_cache_populated) {
334		len = cache_ppi_operations(chip->acpi_dev_handle, buf);
335		if (len < 0) {
336			mutex_unlock(&tpm_ppi_lock);
337			return len;
338		}
339
340		ppi_cache_populated = true;
341	}
342
343	for (i = 0; i <= PPI_TPM_REQ_MAX; i++) {
344		ret = ppi_operations_cache[i];
345		if (ret >= 0 && ret < ARRAY_SIZE(tpm_ppi_info))
346			len += sysfs_emit_at(buf, len, "%d %d: %s\n",
347							i, ret, tpm_ppi_info[ret]);
348	}
349	mutex_unlock(&tpm_ppi_lock);
350
351	return len;
352}
353
354static ssize_t tpm_show_ppi_vs_operations(struct device *dev,
355					  struct device_attribute *attr,
356					  char *buf)
357{
358	struct tpm_chip *chip = to_tpm_chip(dev);
359	ssize_t len = 0;
360	u32 ret;
361	int i;
362
363	mutex_lock(&tpm_ppi_lock);
364	if (!ppi_cache_populated) {
365		len = cache_ppi_operations(chip->acpi_dev_handle, buf);
366		if (len < 0) {
367			mutex_unlock(&tpm_ppi_lock);
368			return len;
369		}
370
371		ppi_cache_populated = true;
372	}
373
374	for (i = PPI_VS_REQ_START; i <= PPI_VS_REQ_END; i++) {
375		ret = ppi_operations_cache[i];
376		if (ret >= 0 && ret < ARRAY_SIZE(tpm_ppi_info))
377			len += sysfs_emit_at(buf, len, "%d %d: %s\n",
378							i, ret, tpm_ppi_info[ret]);
379	}
380	mutex_unlock(&tpm_ppi_lock);
381
382	return len;
383}
384
385static DEVICE_ATTR(version, S_IRUGO, tpm_show_ppi_version, NULL);
386static DEVICE_ATTR(request, S_IRUGO | S_IWUSR | S_IWGRP,
387		   tpm_show_ppi_request, tpm_store_ppi_request);
388static DEVICE_ATTR(transition_action, S_IRUGO,
389		   tpm_show_ppi_transition_action, NULL);
390static DEVICE_ATTR(response, S_IRUGO, tpm_show_ppi_response, NULL);
391static DEVICE_ATTR(tcg_operations, S_IRUGO, tpm_show_ppi_tcg_operations, NULL);
392static DEVICE_ATTR(vs_operations, S_IRUGO, tpm_show_ppi_vs_operations, NULL);
393
394static struct attribute *ppi_attrs[] = {
395	&dev_attr_version.attr,
396	&dev_attr_request.attr,
397	&dev_attr_transition_action.attr,
398	&dev_attr_response.attr,
399	&dev_attr_tcg_operations.attr,
400	&dev_attr_vs_operations.attr, NULL,
401};
402static const struct attribute_group ppi_attr_grp = {
403	.name = "ppi",
404	.attrs = ppi_attrs
405};
406
407void tpm_add_ppi(struct tpm_chip *chip)
408{
409	union acpi_object *obj;
410
411	if (!chip->acpi_dev_handle)
412		return;
413
414	if (!acpi_check_dsm(chip->acpi_dev_handle, &tpm_ppi_guid,
415			    TPM_PPI_REVISION_ID_1, 1 << TPM_PPI_FN_VERSION))
416		return;
417
418	/* Cache PPI version string. */
419	obj = acpi_evaluate_dsm_typed(chip->acpi_dev_handle, &tpm_ppi_guid,
420				      TPM_PPI_REVISION_ID_1,
421				      TPM_PPI_FN_VERSION,
422				      NULL, ACPI_TYPE_STRING);
423	if (obj) {
424		strscpy(chip->ppi_version, obj->string.pointer,
425			sizeof(chip->ppi_version));
426		ACPI_FREE(obj);
427	}
428
429	chip->groups[chip->groups_cnt++] = &ppi_attr_grp;
430}