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tpm_ppi.c
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1 #include <linux/acpi.h>
2 #include <acpi/acpi_drivers.h>
3 #include "tpm.h"
4 
5 static const u8 tpm_ppi_uuid[] = {
6  0xA6, 0xFA, 0xDD, 0x3D,
7  0x1B, 0x36,
8  0xB4, 0x4E,
9  0xA4, 0x24,
10  0x8D, 0x10, 0x08, 0x9D, 0x16, 0x53
11 };
12 static char *tpm_device_name = "TPM";
13 
14 #define TPM_PPI_REVISION_ID 1
15 #define TPM_PPI_FN_VERSION 1
16 #define TPM_PPI_FN_SUBREQ 2
17 #define TPM_PPI_FN_GETREQ 3
18 #define TPM_PPI_FN_GETACT 4
19 #define TPM_PPI_FN_GETRSP 5
20 #define TPM_PPI_FN_SUBREQ2 7
21 #define TPM_PPI_FN_GETOPR 8
22 #define PPI_TPM_REQ_MAX 22
23 #define PPI_VS_REQ_START 128
24 #define PPI_VS_REQ_END 255
25 #define PPI_VERSION_LEN 3
26 
27 static acpi_status ppi_callback(acpi_handle handle, u32 level, void *context,
28  void **return_value)
29 {
30  acpi_status status;
31  struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
32  status = acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
33  if (strstr(buffer.pointer, context) != NULL) {
34  *return_value = handle;
35  kfree(buffer.pointer);
36  return AE_CTRL_TERMINATE;
37  }
38  return AE_OK;
39 }
40 
41 static inline void ppi_assign_params(union acpi_object params[4],
42  u64 function_num)
43 {
44  params[0].type = ACPI_TYPE_BUFFER;
45  params[0].buffer.length = sizeof(tpm_ppi_uuid);
46  params[0].buffer.pointer = (char *)tpm_ppi_uuid;
47  params[1].type = ACPI_TYPE_INTEGER;
48  params[1].integer.value = TPM_PPI_REVISION_ID;
49  params[2].type = ACPI_TYPE_INTEGER;
50  params[2].integer.value = function_num;
51  params[3].type = ACPI_TYPE_PACKAGE;
52  params[3].package.count = 0;
53  params[3].package.elements = NULL;
54 }
55 
56 static ssize_t tpm_show_ppi_version(struct device *dev,
57  struct device_attribute *attr, char *buf)
58 {
59  acpi_handle handle;
60  acpi_status status;
61  struct acpi_object_list input;
62  struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
63  union acpi_object params[4];
64  union acpi_object *obj;
65 
66  input.count = 4;
67  ppi_assign_params(params, TPM_PPI_FN_VERSION);
68  input.pointer = params;
69  status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
70  ACPI_UINT32_MAX, ppi_callback, NULL,
71  tpm_device_name, &handle);
72  if (ACPI_FAILURE(status))
73  return -ENXIO;
74 
75  status = acpi_evaluate_object_typed(handle, "_DSM", &input, &output,
76  ACPI_TYPE_STRING);
77  if (ACPI_FAILURE(status))
78  return -ENOMEM;
79  obj = (union acpi_object *)output.pointer;
80  status = scnprintf(buf, PAGE_SIZE, "%s\n", obj->string.pointer);
81  kfree(output.pointer);
82  return status;
83 }
84 
85 static ssize_t tpm_show_ppi_request(struct device *dev,
86  struct device_attribute *attr, char *buf)
87 {
88  acpi_handle handle;
89  acpi_status status;
90  struct acpi_object_list input;
91  struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
92  union acpi_object params[4];
93  union acpi_object *ret_obj;
94 
95  input.count = 4;
96  ppi_assign_params(params, TPM_PPI_FN_GETREQ);
97  input.pointer = params;
98  status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
99  ACPI_UINT32_MAX, ppi_callback, NULL,
100  tpm_device_name, &handle);
101  if (ACPI_FAILURE(status))
102  return -ENXIO;
103 
104  status = acpi_evaluate_object_typed(handle, "_DSM", &input, &output,
105  ACPI_TYPE_PACKAGE);
106  if (ACPI_FAILURE(status))
107  return -ENOMEM;
108  /*
109  * output.pointer should be of package type, including two integers.
110  * The first is function return code, 0 means success and 1 means
111  * error. The second is pending TPM operation requested by the OS, 0
112  * means none and >0 means operation value.
113  */
114  ret_obj = ((union acpi_object *)output.pointer)->package.elements;
115  if (ret_obj->type == ACPI_TYPE_INTEGER) {
116  if (ret_obj->integer.value) {
117  status = -EFAULT;
118  goto cleanup;
119  }
120  ret_obj++;
121  if (ret_obj->type == ACPI_TYPE_INTEGER)
122  status = scnprintf(buf, PAGE_SIZE, "%llu\n",
123  ret_obj->integer.value);
124  else
125  status = -EINVAL;
126  } else {
127  status = -EINVAL;
128  }
129 cleanup:
130  kfree(output.pointer);
131  return status;
132 }
133 
134 static ssize_t tpm_store_ppi_request(struct device *dev,
135  struct device_attribute *attr,
136  const char *buf, size_t count)
137 {
138  char version[PPI_VERSION_LEN + 1];
139  acpi_handle handle;
140  acpi_status status;
141  struct acpi_object_list input;
142  struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
143  union acpi_object params[4];
144  union acpi_object obj;
145  u32 req;
146  u64 ret;
147 
148  input.count = 4;
149  ppi_assign_params(params, TPM_PPI_FN_VERSION);
150  input.pointer = params;
151  status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
152  ACPI_UINT32_MAX, ppi_callback, NULL,
153  tpm_device_name, &handle);
154  if (ACPI_FAILURE(status))
155  return -ENXIO;
156 
157  status = acpi_evaluate_object_typed(handle, "_DSM", &input, &output,
158  ACPI_TYPE_STRING);
159  if (ACPI_FAILURE(status))
160  return -ENOMEM;
161  strncpy(version,
162  ((union acpi_object *)output.pointer)->string.pointer,
163  PPI_VERSION_LEN);
164  kfree(output.pointer);
165  output.length = ACPI_ALLOCATE_BUFFER;
166  output.pointer = NULL;
167  /*
168  * the function to submit TPM operation request to pre-os environment
169  * is updated with function index from SUBREQ to SUBREQ2 since PPI
170  * version 1.1
171  */
172  if (strcmp(version, "1.1") == -1)
173  params[2].integer.value = TPM_PPI_FN_SUBREQ;
174  else
175  params[2].integer.value = TPM_PPI_FN_SUBREQ2;
176  /*
177  * PPI spec defines params[3].type as ACPI_TYPE_PACKAGE. Some BIOS
178  * accept buffer/string/integer type, but some BIOS accept buffer/
179  * string/package type. For PPI version 1.0 and 1.1, use buffer type
180  * for compatibility, and use package type since 1.2 according to spec.
181  */
182  if (strcmp(version, "1.2") == -1) {
183  params[3].type = ACPI_TYPE_BUFFER;
184  params[3].buffer.length = sizeof(req);
185  sscanf(buf, "%d", &req);
186  params[3].buffer.pointer = (char *)&req;
187  } else {
188  params[3].package.count = 1;
189  obj.type = ACPI_TYPE_INTEGER;
190  sscanf(buf, "%llu", &obj.integer.value);
191  params[3].package.elements = &obj;
192  }
193 
194  status = acpi_evaluate_object_typed(handle, "_DSM", &input, &output,
195  ACPI_TYPE_INTEGER);
196  if (ACPI_FAILURE(status))
197  return -ENOMEM;
198  ret = ((union acpi_object *)output.pointer)->integer.value;
199  if (ret == 0)
200  status = (acpi_status)count;
201  else if (ret == 1)
202  status = -EPERM;
203  else
204  status = -EFAULT;
205  kfree(output.pointer);
206  return status;
207 }
208 
209 static ssize_t tpm_show_ppi_transition_action(struct device *dev,
210  struct device_attribute *attr,
211  char *buf)
212 {
213  char version[PPI_VERSION_LEN + 1];
214  acpi_handle handle;
215  acpi_status status;
216  struct acpi_object_list input;
217  struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
218  union acpi_object params[4];
219  u32 ret;
220  char *info[] = {
221  "None",
222  "Shutdown",
223  "Reboot",
224  "OS Vendor-specific",
225  "Error",
226  };
227  input.count = 4;
228  ppi_assign_params(params, TPM_PPI_FN_VERSION);
229  input.pointer = params;
230  status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
231  ACPI_UINT32_MAX, ppi_callback, NULL,
232  tpm_device_name, &handle);
233  if (ACPI_FAILURE(status))
234  return -ENXIO;
235 
236  status = acpi_evaluate_object_typed(handle, "_DSM", &input, &output,
237  ACPI_TYPE_STRING);
238  if (ACPI_FAILURE(status))
239  return -ENOMEM;
240  strncpy(version,
241  ((union acpi_object *)output.pointer)->string.pointer,
242  PPI_VERSION_LEN);
243  /*
244  * PPI spec defines params[3].type as empty package, but some platforms
245  * (e.g. Capella with PPI 1.0) need integer/string/buffer type, so for
246  * compatibility, define params[3].type as buffer, if PPI version < 1.2
247  */
248  if (strcmp(version, "1.2") == -1) {
249  params[3].type = ACPI_TYPE_BUFFER;
250  params[3].buffer.length = 0;
251  params[3].buffer.pointer = NULL;
252  }
253  params[2].integer.value = TPM_PPI_FN_GETACT;
254  kfree(output.pointer);
255  output.length = ACPI_ALLOCATE_BUFFER;
256  output.pointer = NULL;
257  status = acpi_evaluate_object_typed(handle, "_DSM", &input, &output,
258  ACPI_TYPE_INTEGER);
259  if (ACPI_FAILURE(status))
260  return -ENOMEM;
261  ret = ((union acpi_object *)output.pointer)->integer.value;
262  if (ret < ARRAY_SIZE(info) - 1)
263  status = scnprintf(buf, PAGE_SIZE, "%d: %s\n", ret, info[ret]);
264  else
265  status = scnprintf(buf, PAGE_SIZE, "%d: %s\n", ret,
266  info[ARRAY_SIZE(info)-1]);
267  kfree(output.pointer);
268  return status;
269 }
270 
271 static ssize_t tpm_show_ppi_response(struct device *dev,
272  struct device_attribute *attr,
273  char *buf)
274 {
275  acpi_handle handle;
276  acpi_status status;
277  struct acpi_object_list input;
278  struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
279  union acpi_object params[4];
280  union acpi_object *ret_obj;
281  u64 req;
282 
283  input.count = 4;
284  ppi_assign_params(params, TPM_PPI_FN_GETRSP);
285  input.pointer = params;
286  status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
287  ACPI_UINT32_MAX, ppi_callback, NULL,
288  tpm_device_name, &handle);
289  if (ACPI_FAILURE(status))
290  return -ENXIO;
291 
292  status = acpi_evaluate_object_typed(handle, "_DSM", &input, &output,
293  ACPI_TYPE_PACKAGE);
294  if (ACPI_FAILURE(status))
295  return -ENOMEM;
296  /*
297  * parameter output.pointer should be of package type, including
298  * 3 integers. The first means function return code, the second means
299  * most recent TPM operation request, and the last means response to
300  * the most recent TPM operation request. Only if the first is 0, and
301  * the second integer is not 0, the response makes sense.
302  */
303  ret_obj = ((union acpi_object *)output.pointer)->package.elements;
304  if (ret_obj->type != ACPI_TYPE_INTEGER) {
305  status = -EINVAL;
306  goto cleanup;
307  }
308  if (ret_obj->integer.value) {
309  status = -EFAULT;
310  goto cleanup;
311  }
312  ret_obj++;
313  if (ret_obj->type != ACPI_TYPE_INTEGER) {
314  status = -EINVAL;
315  goto cleanup;
316  }
317  if (ret_obj->integer.value) {
318  req = ret_obj->integer.value;
319  ret_obj++;
320  if (ret_obj->type != ACPI_TYPE_INTEGER) {
321  status = -EINVAL;
322  goto cleanup;
323  }
324  if (ret_obj->integer.value == 0)
325  status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
326  "0: Success");
327  else if (ret_obj->integer.value == 0xFFFFFFF0)
328  status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
329  "0xFFFFFFF0: User Abort");
330  else if (ret_obj->integer.value == 0xFFFFFFF1)
331  status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
332  "0xFFFFFFF1: BIOS Failure");
333  else if (ret_obj->integer.value >= 1 &&
334  ret_obj->integer.value <= 0x00000FFF)
335  status = scnprintf(buf, PAGE_SIZE, "%llu %llu: %s\n",
336  req, ret_obj->integer.value,
337  "Corresponding TPM error");
338  else
339  status = scnprintf(buf, PAGE_SIZE, "%llu %llu: %s\n",
340  req, ret_obj->integer.value,
341  "Error");
342  } else {
343  status = scnprintf(buf, PAGE_SIZE, "%llu: %s\n",
344  ret_obj->integer.value, "No Recent Request");
345  }
346 cleanup:
347  kfree(output.pointer);
348  return status;
349 }
350 
351 static ssize_t show_ppi_operations(char *buf, u32 start, u32 end)
352 {
353  char *str = buf;
354  char version[PPI_VERSION_LEN];
355  acpi_handle handle;
356  acpi_status status;
357  struct acpi_object_list input;
358  struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
359  union acpi_object params[4];
360  union acpi_object obj;
361  int i;
362  u32 ret;
363  char *info[] = {
364  "Not implemented",
365  "BIOS only",
366  "Blocked for OS by BIOS",
367  "User required",
368  "User not required",
369  };
370  input.count = 4;
371  ppi_assign_params(params, TPM_PPI_FN_VERSION);
372  input.pointer = params;
373  status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
374  ACPI_UINT32_MAX, ppi_callback, NULL,
375  tpm_device_name, &handle);
376  if (ACPI_FAILURE(status))
377  return -ENXIO;
378 
379  status = acpi_evaluate_object_typed(handle, "_DSM", &input, &output,
380  ACPI_TYPE_STRING);
381  if (ACPI_FAILURE(status))
382  return -ENOMEM;
383 
384  strncpy(version,
385  ((union acpi_object *)output.pointer)->string.pointer,
386  PPI_VERSION_LEN);
387  kfree(output.pointer);
388  output.length = ACPI_ALLOCATE_BUFFER;
389  output.pointer = NULL;
390  if (strcmp(version, "1.2") == -1)
391  return -EPERM;
392 
393  params[2].integer.value = TPM_PPI_FN_GETOPR;
394  params[3].package.count = 1;
395  obj.type = ACPI_TYPE_INTEGER;
396  params[3].package.elements = &obj;
397  for (i = start; i <= end; i++) {
398  obj.integer.value = i;
399  status = acpi_evaluate_object_typed(handle, "_DSM",
400  &input, &output, ACPI_TYPE_INTEGER);
401  if (ACPI_FAILURE(status))
402  return -ENOMEM;
403 
404  ret = ((union acpi_object *)output.pointer)->integer.value;
405  if (ret > 0 && ret < ARRAY_SIZE(info))
406  str += scnprintf(str, PAGE_SIZE, "%d %d: %s\n",
407  i, ret, info[ret]);
408  kfree(output.pointer);
409  output.length = ACPI_ALLOCATE_BUFFER;
410  output.pointer = NULL;
411  }
412  return str - buf;
413 }
414 
415 static ssize_t tpm_show_ppi_tcg_operations(struct device *dev,
416  struct device_attribute *attr,
417  char *buf)
418 {
419  return show_ppi_operations(buf, 0, PPI_TPM_REQ_MAX);
420 }
421 
422 static ssize_t tpm_show_ppi_vs_operations(struct device *dev,
423  struct device_attribute *attr,
424  char *buf)
425 {
426  return show_ppi_operations(buf, PPI_VS_REQ_START, PPI_VS_REQ_END);
427 }
428 
429 static DEVICE_ATTR(version, S_IRUGO, tpm_show_ppi_version, NULL);
430 static DEVICE_ATTR(request, S_IRUGO | S_IWUSR | S_IWGRP,
431  tpm_show_ppi_request, tpm_store_ppi_request);
432 static DEVICE_ATTR(transition_action, S_IRUGO,
433  tpm_show_ppi_transition_action, NULL);
434 static DEVICE_ATTR(response, S_IRUGO, tpm_show_ppi_response, NULL);
435 static DEVICE_ATTR(tcg_operations, S_IRUGO, tpm_show_ppi_tcg_operations, NULL);
436 static DEVICE_ATTR(vs_operations, S_IRUGO, tpm_show_ppi_vs_operations, NULL);
437 
438 static struct attribute *ppi_attrs[] = {
439  &dev_attr_version.attr,
440  &dev_attr_request.attr,
441  &dev_attr_transition_action.attr,
442  &dev_attr_response.attr,
443  &dev_attr_tcg_operations.attr,
444  &dev_attr_vs_operations.attr, NULL,
445 };
446 static struct attribute_group ppi_attr_grp = {
447  .name = "ppi",
448  .attrs = ppi_attrs
449 };
450 
451 int tpm_add_ppi(struct kobject *parent)
452 {
453  return sysfs_create_group(parent, &ppi_attr_grp);
454 }
455 EXPORT_SYMBOL_GPL(tpm_add_ppi);
456 
457 void tpm_remove_ppi(struct kobject *parent)
458 {
459  sysfs_remove_group(parent, &ppi_attr_grp);
460 }
461 EXPORT_SYMBOL_GPL(tpm_remove_ppi);
462 
463 MODULE_LICENSE("GPL");
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