drivers/char/tpm/tpm_ppi.c

   1 #include <linux/acpi.h>
   2 #include "tpm.h"
   3
   4 #define TPM_PPI_REVISION_ID     1
   5 #define TPM_PPI_FN_VERSION      1
   6 #define TPM_PPI_FN_SUBREQ       2
   7 #define TPM_PPI_FN_GETREQ       3
   8 #define TPM_PPI_FN_GETACT       4
   9 #define TPM_PPI_FN_GETRSP       5
  10 #define TPM_PPI_FN_SUBREQ2      7
  11 #define TPM_PPI_FN_GETOPR       8
  12 #define PPI_TPM_REQ_MAX         22
  13 #define PPI_VS_REQ_START        128
  14 #define PPI_VS_REQ_END          255
  15 #define PPI_VERSION_LEN         3
  16
  17 static const u8 tpm_ppi_uuid[] = {
  18         0xA6, 0xFA, 0xDD, 0x3D,
  19         0x1B, 0x36,
  20         0xB4, 0x4E,
  21         0xA4, 0x24,
  22         0x8D, 0x10, 0x08, 0x9D, 0x16, 0x53
  23 };
  24
  25 static char tpm_ppi_version[PPI_VERSION_LEN + 1];
  26 static acpi_handle tpm_ppi_handle;
  27
  28 static acpi_status ppi_callback(acpi_handle handle, u32 level, void *context,
  29                                 void **return_value)
  30 {
  31         union acpi_object *obj;
  32
  33         if (!acpi_check_dsm(handle, tpm_ppi_uuid, TPM_PPI_REVISION_ID,
  34                             1 << TPM_PPI_FN_VERSION))
  35                 return AE_OK;
  36
  37         /* Cache version string */
  38         obj = acpi_evaluate_dsm_typed(handle, tpm_ppi_uuid,
  39                                       TPM_PPI_REVISION_ID, TPM_PPI_FN_VERSION,
  40                                       NULL, ACPI_TYPE_STRING);
  41         if (obj) {
  42                 strlcpy(tpm_ppi_version, obj->string.pointer,
  43                         PPI_VERSION_LEN + 1);
  44                 ACPI_FREE(obj);
  45         }
  46
  47         *return_value = handle;
  48
  49         return AE_CTRL_TERMINATE;
  50 }
  51
  52 static inline union acpi_object *
  53 tpm_eval_dsm(int func, acpi_object_type type, union acpi_object *argv4)
  54 {
  55         BUG_ON(!tpm_ppi_handle);
  56         return acpi_evaluate_dsm_typed(tpm_ppi_handle, tpm_ppi_uuid,
  57                                        TPM_PPI_REVISION_ID, func, argv4, type);
  58 }
  59
  60 static ssize_t tpm_show_ppi_version(struct device *dev,
  61                                     struct device_attribute *attr, char *buf)
  62 {
  63         return scnprintf(buf, PAGE_SIZE, "%s\n", tpm_ppi_version);
  64 }
  65
  66 static ssize_t tpm_show_ppi_request(struct device *dev,
  67                                     struct device_attribute *attr, char *buf)
  68 {
  69         ssize_t size = -EINVAL;
  70         union acpi_object *obj;
  71
  72         obj = tpm_eval_dsm(TPM_PPI_FN_GETREQ, ACPI_TYPE_PACKAGE, NULL);
  73         if (!obj)
  74                 return -ENXIO;
  75
  76         /*
  77          * output.pointer should be of package type, including two integers.
  78          * The first is function return code, 0 means success and 1 means
  79          * error. The second is pending TPM operation requested by the OS, 0
  80          * means none and >0 means operation value.
  81          */
  82         if (obj->package.count == 2 &&
  83             obj->package.elements[0].type == ACPI_TYPE_INTEGER &&
  84             obj->package.elements[1].type == ACPI_TYPE_INTEGER) {
  85                 if (obj->package.elements[0].integer.value)
  86                         size = -EFAULT;
  87                 else
  88                         size = scnprintf(buf, PAGE_SIZE, "%llu\n",
  89                                  obj->package.elements[1].integer.value);
  90         }
  91
  92         ACPI_FREE(obj);
  93
  94         return size;
  95 }
  96
  97 static ssize_t tpm_store_ppi_request(struct device *dev,
  98                                      struct device_attribute *attr,
  99                                      const char *buf, size_t count)
 100 {
 101         u32 req;
 102         u64 ret;
 103         int func = TPM_PPI_FN_SUBREQ;
 104         union acpi_object *obj, tmp;
 105         union acpi_object argv4 = ACPI_INIT_DSM_ARGV4(1, &tmp);
 106
 107         /*
 108          * the function to submit TPM operation request to pre-os environment
 109          * is updated with function index from SUBREQ to SUBREQ2 since PPI
 110          * version 1.1
 111          */
 112         if (acpi_check_dsm(tpm_ppi_handle, tpm_ppi_uuid, TPM_PPI_REVISION_ID,
 113                            1 << TPM_PPI_FN_SUBREQ2))
 114                 func = TPM_PPI_FN_SUBREQ2;
 115
 116         /*
 117          * PPI spec defines params[3].type as ACPI_TYPE_PACKAGE. Some BIOS
 118          * accept buffer/string/integer type, but some BIOS accept buffer/
 119          * string/package type. For PPI version 1.0 and 1.1, use buffer type
 120          * for compatibility, and use package type since 1.2 according to spec.
 121          */
 122         if (strcmp(tpm_ppi_version, "1.2") < 0) {
 123                 if (sscanf(buf, "%d", &req) != 1)
 124                         return -EINVAL;
 125                 argv4.type = ACPI_TYPE_BUFFER;
 126                 argv4.buffer.length = sizeof(req);
 127                 argv4.buffer.pointer = (u8 *)&req;
 128         } else {
 129                 tmp.type = ACPI_TYPE_INTEGER;
 130                 if (sscanf(buf, "%llu", &tmp.integer.value) != 1)
 131                         return -EINVAL;
 132         }
 133
 134         obj = tpm_eval_dsm(func, ACPI_TYPE_INTEGER, &argv4);
 135         if (!obj) {
 136                 return -ENXIO;
 137         } else {
 138                 ret = obj->integer.value;
 139                 ACPI_FREE(obj);
 140         }
 141
 142         if (ret == 0)
 143                 return (acpi_status)count;
 144
 145         return (ret == 1) ? -EPERM : -EFAULT;
 146 }
 147
 148 static ssize_t tpm_show_ppi_transition_action(struct device *dev,
 149                                               struct device_attribute *attr,
 150                                               char *buf)
 151 {
 152         u32 ret;
 153         acpi_status status;
 154         union acpi_object *obj = NULL;
 155         union acpi_object tmp = {
 156                 .buffer.type = ACPI_TYPE_BUFFER,
 157                 .buffer.length = 0,
 158                 .buffer.pointer = NULL
 159         };
 160
 161         static char *info[] = {
 162                 "None",
 163                 "Shutdown",
 164                 "Reboot",
 165                 "OS Vendor-specific",
 166                 "Error",
 167         };
 168
 169         /*
 170          * PPI spec defines params[3].type as empty package, but some platforms
 171          * (e.g. Capella with PPI 1.0) need integer/string/buffer type, so for
 172          * compatibility, define params[3].type as buffer, if PPI version < 1.2
 173          */
 174         if (strcmp(tpm_ppi_version, "1.2") < 0)
 175                 obj = &tmp;
 176         obj = tpm_eval_dsm(TPM_PPI_FN_GETACT, ACPI_TYPE_INTEGER, obj);
 177         if (!obj) {
 178                 return -ENXIO;
 179         } else {
 180                 ret = obj->integer.value;
 181                 ACPI_FREE(obj);
 182         }
 183
 184         if (ret < ARRAY_SIZE(info) - 1)
 185                 status = scnprintf(buf, PAGE_SIZE, "%d: %s\n", ret, info[ret]);
 186         else
 187                 status = scnprintf(buf, PAGE_SIZE, "%d: %s\n", ret,
 188                                    info[ARRAY_SIZE(info)-1]);
 189         return status;
 190 }
 191
 192 static ssize_t tpm_show_ppi_response(struct device *dev,
 193                                      struct device_attribute *attr,
 194                                      char *buf)
 195 {
 196         acpi_status status = -EINVAL;
 197         union acpi_object *obj, *ret_obj;
 198         u64 req, res;
 199
 200         obj = tpm_eval_dsm(TPM_PPI_FN_GETRSP, ACPI_TYPE_PACKAGE, NULL);
 201         if (!obj)
 202                 return -ENXIO;
 203
 204         /*
 205          * parameter output.pointer should be of package type, including
 206          * 3 integers. The first means function return code, the second means
 207          * most recent TPM operation request, and the last means response to
 208          * the most recent TPM operation request. Only if the first is 0, and
 209          * the second integer is not 0, the response makes sense.
 210          */
 211         ret_obj = obj->package.elements;
 212         if (obj->package.count < 3 ||
 213             ret_obj[0].type != ACPI_TYPE_INTEGER ||
 214             ret_obj[1].type != ACPI_TYPE_INTEGER ||
 215             ret_obj[2].type != ACPI_TYPE_INTEGER)
 216                 goto cleanup;
 217
 218         if (ret_obj[0].integer.value) {
 219                 status = -EFAULT;
 220                 goto cleanup;
 221         }
 222
 223         req = ret_obj[1].integer.value;
 224         res = ret_obj[2].integer.value;
 225         if (req) {
 226                 if (res == 0)
 227                         status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
 228                                            "0: Success");
 229                 else if (res == 0xFFFFFFF0)
 230                         status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
 231                                            "0xFFFFFFF0: User Abort");
 232                 else if (res == 0xFFFFFFF1)
 233                         status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
 234                                            "0xFFFFFFF1: BIOS Failure");
 235                 else if (res >= 1 && res <= 0x00000FFF)
 236                         status = scnprintf(buf, PAGE_SIZE, "%llu %llu: %s\n",
 237                                            req, res, "Corresponding TPM error");
 238                 else
 239                         status = scnprintf(buf, PAGE_SIZE, "%llu %llu: %s\n",
 240                                            req, res, "Error");
 241         } else {
 242                 status = scnprintf(buf, PAGE_SIZE, "%llu: %s\n",
 243                                    req, "No Recent Request");
 244         }
 245
 246 cleanup:
 247         ACPI_FREE(obj);
 248         return status;
 249 }
 250
 251 static ssize_t show_ppi_operations(char *buf, u32 start, u32 end)
 252 {
 253         int i;
 254         u32 ret;
 255         char *str = buf;
 256         union acpi_object *obj, tmp;
 257         union acpi_object argv = ACPI_INIT_DSM_ARGV4(1, &tmp);
 258
 259         static char *info[] = {
 260                 "Not implemented",
 261                 "BIOS only",
 262                 "Blocked for OS by BIOS",
 263                 "User required",
 264                 "User not required",
 265         };
 266
 267         if (!acpi_check_dsm(tpm_ppi_handle, tpm_ppi_uuid, TPM_PPI_REVISION_ID,
 268                             1 << TPM_PPI_FN_GETOPR))
 269                 return -EPERM;
 270
 271         tmp.integer.type = ACPI_TYPE_INTEGER;
 272         for (i = start; i <= end; i++) {
 273                 tmp.integer.value = i;
 274                 obj = tpm_eval_dsm(TPM_PPI_FN_GETOPR, ACPI_TYPE_INTEGER, &argv);
 275                 if (!obj) {
 276                         return -ENOMEM;
 277                 } else {
 278                         ret = obj->integer.value;
 279                         ACPI_FREE(obj);
 280                 }
 281
 282                 if (ret > 0 && ret < ARRAY_SIZE(info))
 283                         str += scnprintf(str, PAGE_SIZE, "%d %d: %s\n",
 284                                          i, ret, info[ret]);
 285         }
 286
 287         return str - buf;
 288 }
 289
 290 static ssize_t tpm_show_ppi_tcg_operations(struct device *dev,
 291                                            struct device_attribute *attr,
 292                                            char *buf)
 293 {
 294         return show_ppi_operations(buf, 0, PPI_TPM_REQ_MAX);
 295 }
 296
 297 static ssize_t tpm_show_ppi_vs_operations(struct device *dev,
 298                                           struct device_attribute *attr,
 299                                           char *buf)
 300 {
 301         return show_ppi_operations(buf, PPI_VS_REQ_START, PPI_VS_REQ_END);
 302 }
 303
 304 static DEVICE_ATTR(version, S_IRUGO, tpm_show_ppi_version, NULL);
 305 static DEVICE_ATTR(request, S_IRUGO | S_IWUSR | S_IWGRP,
 306                    tpm_show_ppi_request, tpm_store_ppi_request);
 307 static DEVICE_ATTR(transition_action, S_IRUGO,
 308                    tpm_show_ppi_transition_action, NULL);
 309 static DEVICE_ATTR(response, S_IRUGO, tpm_show_ppi_response, NULL);
 310 static DEVICE_ATTR(tcg_operations, S_IRUGO, tpm_show_ppi_tcg_operations, NULL);
 311 static DEVICE_ATTR(vs_operations, S_IRUGO, tpm_show_ppi_vs_operations, NULL);
 312
 313 static struct attribute *ppi_attrs[] = {
 314         &dev_attr_version.attr,
 315         &dev_attr_request.attr,
 316         &dev_attr_transition_action.attr,
 317         &dev_attr_response.attr,
 318         &dev_attr_tcg_operations.attr,
 319         &dev_attr_vs_operations.attr, NULL,
 320 };
 321 static struct attribute_group ppi_attr_grp = {
 322         .name = "ppi",
 323         .attrs = ppi_attrs
 324 };
 325
 326 int tpm_add_ppi(struct kobject *parent)
 327 {
 328         /* Cache TPM ACPI handle and version string */
 329         acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, ACPI_UINT32_MAX,
 330                             ppi_callback, NULL, NULL, &tpm_ppi_handle);
 331         return tpm_ppi_handle ? sysfs_create_group(parent, &ppi_attr_grp) : 0;
 332 }
 333
 334 void tpm_remove_ppi(struct kobject *parent)
 335 {
 336         if (tpm_ppi_handle)
 337                 sysfs_remove_group(parent, &ppi_attr_grp);
 338 }