kernel/drivers/char/tpm/tpm_ppi.c

   1 /*
   2  * Copyright (C) 2012-2014 Intel Corporation
   3  *
   4  * Authors:
   5  * Xiaoyan Zhang <xiaoyan.zhang@intel.com>
   6  * Jiang Liu <jiang.liu@linux.intel.com>
   7  * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
   8  *
   9  * Maintained by: <tpmdd-devel@lists.sourceforge.net>
  10  *
  11  * This file contains implementation of the sysfs interface for PPI.
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License
  15  * as published by the Free Software Foundation; version 2
  16  * of the License.
  17  */
  18
  19
  20 #include <linux/acpi.h>
  21 #include "tpm.h"
  22
  23 #define TPM_PPI_REVISION_ID     1
  24 #define TPM_PPI_FN_VERSION      1
  25 #define TPM_PPI_FN_SUBREQ       2
  26 #define TPM_PPI_FN_GETREQ       3
  27 #define TPM_PPI_FN_GETACT       4
  28 #define TPM_PPI_FN_GETRSP       5
  29 #define TPM_PPI_FN_SUBREQ2      7
  30 #define TPM_PPI_FN_GETOPR       8
  31 #define PPI_TPM_REQ_MAX         22
  32 #define PPI_VS_REQ_START        128
  33 #define PPI_VS_REQ_END          255
  34
  35 static const u8 tpm_ppi_uuid[] = {
  36         0xA6, 0xFA, 0xDD, 0x3D,
  37         0x1B, 0x36,
  38         0xB4, 0x4E,
  39         0xA4, 0x24,
  40         0x8D, 0x10, 0x08, 0x9D, 0x16, 0x53
  41 };
  42
  43 static inline union acpi_object *
  44 tpm_eval_dsm(acpi_handle ppi_handle, int func, acpi_object_type type,
  45              union acpi_object *argv4)
  46 {
  47         BUG_ON(!ppi_handle);
  48         return acpi_evaluate_dsm_typed(ppi_handle, tpm_ppi_uuid,
  49                                        TPM_PPI_REVISION_ID,
  50                                        func, argv4, type);
  51 }
  52
  53 static ssize_t tpm_show_ppi_version(struct device *dev,
  54                                     struct device_attribute *attr, char *buf)
  55 {
  56         struct tpm_chip *chip = dev_get_drvdata(dev);
  57
  58         return scnprintf(buf, PAGE_SIZE, "%s\n", chip->ppi_version);
  59 }
  60
  61 static ssize_t tpm_show_ppi_request(struct device *dev,
  62                                     struct device_attribute *attr, char *buf)
  63 {
  64         ssize_t size = -EINVAL;
  65         union acpi_object *obj;
  66         struct tpm_chip *chip = dev_get_drvdata(dev);
  67
  68         obj = tpm_eval_dsm(chip->acpi_dev_handle, TPM_PPI_FN_GETREQ,
  69                            ACPI_TYPE_PACKAGE, NULL);
  70         if (!obj)
  71                 return -ENXIO;
  72
  73         /*
  74          * output.pointer should be of package type, including two integers.
  75          * The first is function return code, 0 means success and 1 means
  76          * error. The second is pending TPM operation requested by the OS, 0
  77          * means none and >0 means operation value.
  78          */
  79         if (obj->package.count == 2 &&
  80             obj->package.elements[0].type == ACPI_TYPE_INTEGER &&
  81             obj->package.elements[1].type == ACPI_TYPE_INTEGER) {
  82                 if (obj->package.elements[0].integer.value)
  83                         size = -EFAULT;
  84                 else
  85                         size = scnprintf(buf, PAGE_SIZE, "%llu\n",
  86                                  obj->package.elements[1].integer.value);
  87         }
  88
  89         ACPI_FREE(obj);
  90
  91         return size;
  92 }
  93
  94 static ssize_t tpm_store_ppi_request(struct device *dev,
  95                                      struct device_attribute *attr,
  96                                      const char *buf, size_t count)
  97 {
  98         u32 req;
  99         u64 ret;
 100         int func = TPM_PPI_FN_SUBREQ;
 101         union acpi_object *obj, tmp;
 102         union acpi_object argv4 = ACPI_INIT_DSM_ARGV4(1, &tmp);
 103         struct tpm_chip *chip = dev_get_drvdata(dev);
 104
 105         /*
 106          * the function to submit TPM operation request to pre-os environment
 107          * is updated with function index from SUBREQ to SUBREQ2 since PPI
 108          * version 1.1
 109          */
 110         if (acpi_check_dsm(chip->acpi_dev_handle, tpm_ppi_uuid,
 111                            TPM_PPI_REVISION_ID, 1 << TPM_PPI_FN_SUBREQ2))
 112                 func = TPM_PPI_FN_SUBREQ2;
 113
 114         /*
 115          * PPI spec defines params[3].type as ACPI_TYPE_PACKAGE. Some BIOS
 116          * accept buffer/string/integer type, but some BIOS accept buffer/
 117          * string/package type. For PPI version 1.0 and 1.1, use buffer type
 118          * for compatibility, and use package type since 1.2 according to spec.
 119          */
 120         if (strcmp(chip->ppi_version, "1.2") < 0) {
 121                 if (sscanf(buf, "%d", &req) != 1)
 122                         return -EINVAL;
 123                 argv4.type = ACPI_TYPE_BUFFER;
 124                 argv4.buffer.length = sizeof(req);
 125                 argv4.buffer.pointer = (u8 *)&req;
 126         } else {
 127                 tmp.type = ACPI_TYPE_INTEGER;
 128                 if (sscanf(buf, "%llu", &tmp.integer.value) != 1)
 129                         return -EINVAL;
 130         }
 131
 132         obj = tpm_eval_dsm(chip->acpi_dev_handle, func, ACPI_TYPE_INTEGER,
 133                            &argv4);
 134         if (!obj) {
 135                 return -ENXIO;
 136         } else {
 137                 ret = obj->integer.value;
 138                 ACPI_FREE(obj);
 139         }
 140
 141         if (ret == 0)
 142                 return (acpi_status)count;
 143
 144         return (ret == 1) ? -EPERM : -EFAULT;
 145 }
 146
 147 static ssize_t tpm_show_ppi_transition_action(struct device *dev,
 148                                               struct device_attribute *attr,
 149                                               char *buf)
 150 {
 151         u32 ret;
 152         acpi_status status;
 153         union acpi_object *obj = NULL;
 154         union acpi_object tmp = {
 155                 .buffer.type = ACPI_TYPE_BUFFER,
 156                 .buffer.length = 0,
 157                 .buffer.pointer = NULL
 158         };
 159         struct tpm_chip *chip = dev_get_drvdata(dev);
 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(chip->ppi_version, "1.2") < 0)
 175                 obj = &tmp;
 176         obj = tpm_eval_dsm(chip->acpi_dev_handle, TPM_PPI_FN_GETACT,
 177                            ACPI_TYPE_INTEGER, obj);
 178         if (!obj) {
 179                 return -ENXIO;
 180         } else {
 181                 ret = obj->integer.value;
 182                 ACPI_FREE(obj);
 183         }
 184
 185         if (ret < ARRAY_SIZE(info) - 1)
 186                 status = scnprintf(buf, PAGE_SIZE, "%d: %s\n", ret, info[ret]);
 187         else
 188                 status = scnprintf(buf, PAGE_SIZE, "%d: %s\n", ret,
 189                                    info[ARRAY_SIZE(info)-1]);
 190         return status;
 191 }
 192
 193 static ssize_t tpm_show_ppi_response(struct device *dev,
 194                                      struct device_attribute *attr,
 195                                      char *buf)
 196 {
 197         acpi_status status = -EINVAL;
 198         union acpi_object *obj, *ret_obj;
 199         u64 req, res;
 200         struct tpm_chip *chip = dev_get_drvdata(dev);
 201
 202         obj = tpm_eval_dsm(chip->acpi_dev_handle, TPM_PPI_FN_GETRSP,
 203                            ACPI_TYPE_PACKAGE, NULL);
 204         if (!obj)
 205                 return -ENXIO;
 206
 207         /*
 208          * parameter output.pointer should be of package type, including
 209          * 3 integers. The first means function return code, the second means
 210          * most recent TPM operation request, and the last means response to
 211          * the most recent TPM operation request. Only if the first is 0, and
 212          * the second integer is not 0, the response makes sense.
 213          */
 214         ret_obj = obj->package.elements;
 215         if (obj->package.count < 3 ||
 216             ret_obj[0].type != ACPI_TYPE_INTEGER ||
 217             ret_obj[1].type != ACPI_TYPE_INTEGER ||
 218             ret_obj[2].type != ACPI_TYPE_INTEGER)
 219                 goto cleanup;
 220
 221         if (ret_obj[0].integer.value) {
 222                 status = -EFAULT;
 223                 goto cleanup;
 224         }
 225
 226         req = ret_obj[1].integer.value;
 227         res = ret_obj[2].integer.value;
 228         if (req) {
 229                 if (res == 0)
 230                         status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
 231                                            "0: Success");
 232                 else if (res == 0xFFFFFFF0)
 233                         status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
 234                                            "0xFFFFFFF0: User Abort");
 235                 else if (res == 0xFFFFFFF1)
 236                         status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
 237                                            "0xFFFFFFF1: BIOS Failure");
 238                 else if (res >= 1 && res <= 0x00000FFF)
 239                         status = scnprintf(buf, PAGE_SIZE, "%llu %llu: %s\n",
 240                                            req, res, "Corresponding TPM error");
 241                 else
 242                         status = scnprintf(buf, PAGE_SIZE, "%llu %llu: %s\n",
 243                                            req, res, "Error");
 244         } else {
 245                 status = scnprintf(buf, PAGE_SIZE, "%llu: %s\n",
 246                                    req, "No Recent Request");
 247         }
 248
 249 cleanup:
 250         ACPI_FREE(obj);
 251         return status;
 252 }
 253
 254 static ssize_t show_ppi_operations(acpi_handle dev_handle, char *buf, u32 start,
 255                                    u32 end)
 256 {
 257         int i;
 258         u32 ret;
 259         char *str = buf;
 260         union acpi_object *obj, tmp;
 261         union acpi_object argv = ACPI_INIT_DSM_ARGV4(1, &tmp);
 262
 263         static char *info[] = {
 264                 "Not implemented",
 265                 "BIOS only",
 266                 "Blocked for OS by BIOS",
 267                 "User required",
 268                 "User not required",
 269         };
 270
 271         if (!acpi_check_dsm(dev_handle, tpm_ppi_uuid, TPM_PPI_REVISION_ID,
 272                             1 << TPM_PPI_FN_GETOPR))
 273                 return -EPERM;
 274
 275         tmp.integer.type = ACPI_TYPE_INTEGER;
 276         for (i = start; i <= end; i++) {
 277                 tmp.integer.value = i;
 278                 obj = tpm_eval_dsm(dev_handle, TPM_PPI_FN_GETOPR,
 279                                    ACPI_TYPE_INTEGER, &argv);
 280                 if (!obj) {
 281                         return -ENOMEM;
 282                 } else {
 283                         ret = obj->integer.value;
 284                         ACPI_FREE(obj);
 285                 }
 286
 287                 if (ret > 0 && ret < ARRAY_SIZE(info))
 288                         str += scnprintf(str, PAGE_SIZE, "%d %d: %s\n",
 289                                          i, ret, info[ret]);
 290         }
 291
 292         return str - buf;
 293 }
 294
 295 static ssize_t tpm_show_ppi_tcg_operations(struct device *dev,
 296                                            struct device_attribute *attr,
 297                                            char *buf)
 298 {
 299         struct tpm_chip *chip = dev_get_drvdata(dev);
 300
 301         return show_ppi_operations(chip->acpi_dev_handle, buf, 0,
 302                                    PPI_TPM_REQ_MAX);
 303 }
 304
 305 static ssize_t tpm_show_ppi_vs_operations(struct device *dev,
 306                                           struct device_attribute *attr,
 307                                           char *buf)
 308 {
 309         struct tpm_chip *chip = dev_get_drvdata(dev);
 310
 311         return show_ppi_operations(chip->acpi_dev_handle, buf, PPI_VS_REQ_START,
 312                                    PPI_VS_REQ_END);
 313 }
 314
 315 static DEVICE_ATTR(version, S_IRUGO, tpm_show_ppi_version, NULL);
 316 static DEVICE_ATTR(request, S_IRUGO | S_IWUSR | S_IWGRP,
 317                    tpm_show_ppi_request, tpm_store_ppi_request);
 318 static DEVICE_ATTR(transition_action, S_IRUGO,
 319                    tpm_show_ppi_transition_action, NULL);
 320 static DEVICE_ATTR(response, S_IRUGO, tpm_show_ppi_response, NULL);
 321 static DEVICE_ATTR(tcg_operations, S_IRUGO, tpm_show_ppi_tcg_operations, NULL);
 322 static DEVICE_ATTR(vs_operations, S_IRUGO, tpm_show_ppi_vs_operations, NULL);
 323
 324 static struct attribute *ppi_attrs[] = {
 325         &dev_attr_version.attr,
 326         &dev_attr_request.attr,
 327         &dev_attr_transition_action.attr,
 328         &dev_attr_response.attr,
 329         &dev_attr_tcg_operations.attr,
 330         &dev_attr_vs_operations.attr, NULL,
 331 };
 332 static struct attribute_group ppi_attr_grp = {
 333         .name = "ppi",
 334         .attrs = ppi_attrs
 335 };
 336
 337 int tpm_add_ppi(struct tpm_chip *chip)
 338 {
 339         union acpi_object *obj;
 340         int rc;
 341
 342         if (!chip->acpi_dev_handle)
 343                 return 0;
 344
 345         if (!acpi_check_dsm(chip->acpi_dev_handle, tpm_ppi_uuid,
 346                             TPM_PPI_REVISION_ID, 1 << TPM_PPI_FN_VERSION))
 347                 return 0;
 348
 349         /* Cache PPI version string. */
 350         obj = acpi_evaluate_dsm_typed(chip->acpi_dev_handle, tpm_ppi_uuid,
 351                                       TPM_PPI_REVISION_ID, TPM_PPI_FN_VERSION,
 352                                       NULL, ACPI_TYPE_STRING);
 353         if (obj) {
 354                 strlcpy(chip->ppi_version, obj->string.pointer,
 355                         sizeof(chip->ppi_version));
 356                 ACPI_FREE(obj);
 357         }
 358
 359         rc = sysfs_create_group(&chip->pdev->kobj, &ppi_attr_grp);
 360
 361         if (!rc)
 362                 chip->flags |= TPM_CHIP_FLAG_PPI;
 363
 364         return rc;
 365 }
 366
 367 void tpm_remove_ppi(struct tpm_chip *chip)
 368 {
 369         if (chip->flags & TPM_CHIP_FLAG_PPI)
 370                 sysfs_remove_group(&chip->pdev->kobj, &ppi_attr_grp);
 371 }