cmd/tpm_test.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (c) 2015 Google, Inc
   4  */
   5
   6 #include <common.h>
   7 #include <command.h>
   8 #include <cpu_func.h>
   9 #include <tpm-v1.h>
  10 #include "tpm-user-utils.h"
  11
  12 /* Prints error and returns on failure */
  13 #define TPM_CHECK(tpm_command) do { \
  14         uint32_t result; \
  15         \
  16         result = (tpm_command); \
  17         if (result != TPM_SUCCESS) { \
  18                 printf("TEST FAILED: line %d: " #tpm_command ": 0x%x\n", \
  19                         __LINE__, result); \
  20                 return result; \
  21         } \
  22 } while (0)
  23
  24 #define INDEX0                  0xda70
  25 #define INDEX1                  0xda71
  26 #define INDEX2                  0xda72
  27 #define INDEX3                  0xda73
  28 #define INDEX_INITIALISED       0xda80
  29 #define PHYS_PRESENCE           4
  30 #define PRESENCE                8
  31
  32 static uint32_t TlclStartupIfNeeded(struct udevice *dev)
  33 {
  34         uint32_t result = tpm_startup(dev, TPM_ST_CLEAR);
  35
  36         return result == TPM_INVALID_POSTINIT ? TPM_SUCCESS : result;
  37 }
  38
  39 static int test_timer(struct udevice *dev)
  40 {
  41         printf("get_timer(0) = %lu\n", get_timer(0));
  42         return 0;
  43 }
  44
  45 static uint32_t tpm_get_flags(struct udevice *dev, uint8_t *disable,
  46                               uint8_t *deactivated, uint8_t *nvlocked)
  47 {
  48         struct tpm_permanent_flags pflags;
  49         uint32_t result;
  50
  51         result = tpm_get_permanent_flags(dev, &pflags);
  52         if (result)
  53                 return result;
  54         if (disable)
  55                 *disable = pflags.disable;
  56         if (deactivated)
  57                 *deactivated = pflags.deactivated;
  58         if (nvlocked)
  59                 *nvlocked = pflags.nv_locked;
  60         debug("TPM: Got flags disable=%d, deactivated=%d, nvlocked=%d\n",
  61               pflags.disable, pflags.deactivated, pflags.nv_locked);
  62
  63         return 0;
  64 }
  65
  66 static uint32_t tpm_nv_write_value_lock(struct udevice *dev, uint32_t index)
  67 {
  68         debug("TPM: Write lock 0x%x\n", index);
  69
  70         return tpm_nv_write_value(dev, index, NULL, 0);
  71 }
  72
  73 static int tpm_is_owned(struct udevice *dev)
  74 {
  75         uint8_t response[TPM_PUBEK_SIZE];
  76         uint32_t result;
  77
  78         result = tpm_read_pubek(dev, response, sizeof(response));
  79
  80         return result != TPM_SUCCESS;
  81 }
  82
  83 static int test_early_extend(struct udevice *dev)
  84 {
  85         uint8_t value_in[20];
  86         uint8_t value_out[20];
  87
  88         printf("Testing earlyextend ...");
  89         tpm_init(dev);
  90         TPM_CHECK(tpm_startup(dev, TPM_ST_CLEAR));
  91         TPM_CHECK(tpm_continue_self_test(dev));
  92         TPM_CHECK(tpm_extend(dev, 1, value_in, value_out));
  93         printf("done\n");
  94         return 0;
  95 }
  96
  97 static int test_early_nvram(struct udevice *dev)
  98 {
  99         uint32_t x;
 100
 101         printf("Testing earlynvram ...");
 102         tpm_init(dev);
 103         TPM_CHECK(tpm_startup(dev, TPM_ST_CLEAR));
 104         TPM_CHECK(tpm_continue_self_test(dev));
 105         TPM_CHECK(tpm_tsc_physical_presence(dev, PRESENCE));
 106         TPM_CHECK(tpm_nv_read_value(dev, INDEX0, (uint8_t *)&x, sizeof(x)));
 107         printf("done\n");
 108         return 0;
 109 }
 110
 111 static int test_early_nvram2(struct udevice *dev)
 112 {
 113         uint32_t x;
 114
 115         printf("Testing earlynvram2 ...");
 116         tpm_init(dev);
 117         TPM_CHECK(tpm_startup(dev, TPM_ST_CLEAR));
 118         TPM_CHECK(tpm_continue_self_test(dev));
 119         TPM_CHECK(tpm_tsc_physical_presence(dev, PRESENCE));
 120         TPM_CHECK(tpm_nv_write_value(dev, INDEX0, (uint8_t *)&x, sizeof(x)));
 121         printf("done\n");
 122         return 0;
 123 }
 124
 125 static int test_enable(struct udevice *dev)
 126 {
 127         uint8_t disable = 0, deactivated = 0;
 128
 129         printf("Testing enable ...\n");
 130         tpm_init(dev);
 131         TPM_CHECK(TlclStartupIfNeeded(dev));
 132         TPM_CHECK(tpm_self_test_full(dev));
 133         TPM_CHECK(tpm_tsc_physical_presence(dev, PRESENCE));
 134         TPM_CHECK(tpm_get_flags(dev, &disable, &deactivated, NULL));
 135         printf("\tdisable is %d, deactivated is %d\n", disable, deactivated);
 136         TPM_CHECK(tpm_physical_enable(dev));
 137         TPM_CHECK(tpm_physical_set_deactivated(dev, 0));
 138         TPM_CHECK(tpm_get_flags(dev, &disable, &deactivated, NULL));
 139         printf("\tdisable is %d, deactivated is %d\n", disable, deactivated);
 140         if (disable == 1 || deactivated == 1)
 141                 printf("\tfailed to enable or activate\n");
 142         printf("\tdone\n");
 143         return 0;
 144 }
 145
 146 #define reboot() do { \
 147         printf("\trebooting...\n"); \
 148         reset_cpu(0); \
 149 } while (0)
 150
 151 static int test_fast_enable(struct udevice *dev)
 152 {
 153         uint8_t disable = 0, deactivated = 0;
 154         int i;
 155
 156         printf("Testing fastenable ...\n");
 157         tpm_init(dev);
 158         TPM_CHECK(TlclStartupIfNeeded(dev));
 159         TPM_CHECK(tpm_self_test_full(dev));
 160         TPM_CHECK(tpm_tsc_physical_presence(dev, PRESENCE));
 161         TPM_CHECK(tpm_get_flags(dev, &disable, &deactivated, NULL));
 162         printf("\tdisable is %d, deactivated is %d\n", disable, deactivated);
 163         for (i = 0; i < 2; i++) {
 164                 TPM_CHECK(tpm_force_clear(dev));
 165                 TPM_CHECK(tpm_get_flags(dev, &disable, &deactivated, NULL));
 166                 printf("\tdisable is %d, deactivated is %d\n", disable,
 167                        deactivated);
 168                 assert(disable == 1 && deactivated == 1);
 169                 TPM_CHECK(tpm_physical_enable(dev));
 170                 TPM_CHECK(tpm_physical_set_deactivated(dev, 0));
 171                 TPM_CHECK(tpm_get_flags(dev, &disable, &deactivated, NULL));
 172                 printf("\tdisable is %d, deactivated is %d\n", disable,
 173                        deactivated);
 174                 assert(disable == 0 && deactivated == 0);
 175         }
 176         printf("\tdone\n");
 177         return 0;
 178 }
 179
 180 static int test_global_lock(struct udevice *dev)
 181 {
 182         uint32_t zero = 0;
 183         uint32_t result;
 184         uint32_t x;
 185
 186         printf("Testing globallock ...\n");
 187         tpm_init(dev);
 188         TPM_CHECK(TlclStartupIfNeeded(dev));
 189         TPM_CHECK(tpm_self_test_full(dev));
 190         TPM_CHECK(tpm_tsc_physical_presence(dev, PRESENCE));
 191         TPM_CHECK(tpm_nv_read_value(dev, INDEX0, (uint8_t *)&x, sizeof(x)));
 192         TPM_CHECK(tpm_nv_write_value(dev, INDEX0, (uint8_t *)&zero,
 193                                      sizeof(uint32_t)));
 194         TPM_CHECK(tpm_nv_read_value(dev, INDEX1, (uint8_t *)&x, sizeof(x)));
 195         TPM_CHECK(tpm_nv_write_value(dev, INDEX1, (uint8_t *)&zero,
 196                                      sizeof(uint32_t)));
 197         TPM_CHECK(tpm_set_global_lock(dev));
 198         /* Verifies that write to index0 fails */
 199         x = 1;
 200         result = tpm_nv_write_value(dev, INDEX0, (uint8_t *)&x, sizeof(x));
 201         assert(result == TPM_AREA_LOCKED);
 202         TPM_CHECK(tpm_nv_read_value(dev, INDEX0, (uint8_t *)&x, sizeof(x)));
 203         assert(x == 0);
 204         /* Verifies that write to index1 is still possible */
 205         x = 2;
 206         TPM_CHECK(tpm_nv_write_value(dev, INDEX1, (uint8_t *)&x, sizeof(x)));
 207         TPM_CHECK(tpm_nv_read_value(dev, INDEX1, (uint8_t *)&x, sizeof(x)));
 208         assert(x == 2);
 209         /* Turns off PP */
 210         tpm_tsc_physical_presence(dev, PHYS_PRESENCE);
 211         /* Verifies that write to index1 fails */
 212         x = 3;
 213         result = tpm_nv_write_value(dev, INDEX1, (uint8_t *)&x, sizeof(x));
 214         assert(result == TPM_BAD_PRESENCE);
 215         TPM_CHECK(tpm_nv_read_value(dev, INDEX1, (uint8_t *)&x, sizeof(x)));
 216         assert(x == 2);
 217         printf("\tdone\n");
 218         return 0;
 219 }
 220
 221 static int test_lock(struct udevice *dev)
 222 {
 223         printf("Testing lock ...\n");
 224         tpm_init(dev);
 225         tpm_startup(dev, TPM_ST_CLEAR);
 226         tpm_self_test_full(dev);
 227         tpm_tsc_physical_presence(dev, PRESENCE);
 228         tpm_nv_write_value_lock(dev, INDEX0);
 229         printf("\tLocked 0x%x\n", INDEX0);
 230         printf("\tdone\n");
 231         return 0;
 232 }
 233
 234 static void initialise_spaces(struct udevice *dev)
 235 {
 236         uint32_t zero = 0;
 237         uint32_t perm = TPM_NV_PER_WRITE_STCLEAR | TPM_NV_PER_PPWRITE;
 238
 239         printf("\tInitialising spaces\n");
 240         tpm_nv_set_locked(dev);  /* useful only the first time */
 241         tpm_nv_define_space(dev, INDEX0, perm, 4);
 242         tpm_nv_write_value(dev, INDEX0, (uint8_t *)&zero, 4);
 243         tpm_nv_define_space(dev, INDEX1, perm, 4);
 244         tpm_nv_write_value(dev, INDEX1, (uint8_t *)&zero, 4);
 245         tpm_nv_define_space(dev, INDEX2, perm, 4);
 246         tpm_nv_write_value(dev, INDEX2, (uint8_t *)&zero, 4);
 247         tpm_nv_define_space(dev, INDEX3, perm, 4);
 248         tpm_nv_write_value(dev, INDEX3, (uint8_t *)&zero, 4);
 249         perm = TPM_NV_PER_READ_STCLEAR | TPM_NV_PER_WRITE_STCLEAR |
 250                 TPM_NV_PER_PPWRITE;
 251         tpm_nv_define_space(dev, INDEX_INITIALISED, perm, 1);
 252 }
 253
 254 static int test_readonly(struct udevice *dev)
 255 {
 256         uint8_t c;
 257         uint32_t index_0, index_1, index_2, index_3;
 258         int read0, read1, read2, read3;
 259
 260         printf("Testing readonly ...\n");
 261         tpm_init(dev);
 262         tpm_startup(dev, TPM_ST_CLEAR);
 263         tpm_self_test_full(dev);
 264         tpm_tsc_physical_presence(dev, PRESENCE);
 265         /*
 266          * Checks if initialisation has completed by trying to read-lock a
 267          * space that's created at the end of initialisation
 268          */
 269         if (tpm_nv_read_value(dev, INDEX_INITIALISED, &c, 0) == TPM_BADINDEX) {
 270                 /* The initialisation did not complete */
 271                 initialise_spaces(dev);
 272         }
 273
 274         /* Checks if spaces are OK or messed up */
 275         read0 = tpm_nv_read_value(dev, INDEX0, (uint8_t *)&index_0,
 276                                   sizeof(index_0));
 277         read1 = tpm_nv_read_value(dev, INDEX1, (uint8_t *)&index_1,
 278                                   sizeof(index_1));
 279         read2 = tpm_nv_read_value(dev, INDEX2, (uint8_t *)&index_2,
 280                                   sizeof(index_2));
 281         read3 = tpm_nv_read_value(dev, INDEX3, (uint8_t *)&index_3,
 282                                   sizeof(index_3));
 283         if (read0 || read1 || read2 || read3) {
 284                 printf("Invalid contents\n");
 285                 return 0;
 286         }
 287
 288         /*
 289          * Writes space, and locks it.  Then attempts to write again.
 290          * I really wish I could use the imperative.
 291          */
 292         index_0 += 1;
 293         if (tpm_nv_write_value(dev, INDEX0, (uint8_t *)&index_0,
 294                                sizeof(index_0) !=
 295                 TPM_SUCCESS)) {
 296                 pr_err("\tcould not write index 0\n");
 297         }
 298         tpm_nv_write_value_lock(dev, INDEX0);
 299         if (tpm_nv_write_value(dev, INDEX0, (uint8_t *)&index_0,
 300                                sizeof(index_0)) ==
 301                         TPM_SUCCESS)
 302                 pr_err("\tindex 0 is not locked\n");
 303
 304         printf("\tdone\n");
 305         return 0;
 306 }
 307
 308 static int test_redefine_unowned(struct udevice *dev)
 309 {
 310         uint32_t perm;
 311         uint32_t result;
 312         uint32_t x;
 313
 314         printf("Testing redefine_unowned ...");
 315         tpm_init(dev);
 316         TPM_CHECK(TlclStartupIfNeeded(dev));
 317         TPM_CHECK(tpm_self_test_full(dev));
 318         TPM_CHECK(tpm_tsc_physical_presence(dev, PRESENCE));
 319         assert(!tpm_is_owned(dev));
 320
 321         /* Ensures spaces exist. */
 322         TPM_CHECK(tpm_nv_read_value(dev, INDEX0, (uint8_t *)&x, sizeof(x)));
 323         TPM_CHECK(tpm_nv_read_value(dev, INDEX1, (uint8_t *)&x, sizeof(x)));
 324
 325         /* Redefines spaces a couple of times. */
 326         perm = TPM_NV_PER_PPWRITE | TPM_NV_PER_GLOBALLOCK;
 327         TPM_CHECK(tpm_nv_define_space(dev, INDEX0, perm, 2 * sizeof(uint32_t)));
 328         TPM_CHECK(tpm_nv_define_space(dev, INDEX0, perm, sizeof(uint32_t)));
 329         perm = TPM_NV_PER_PPWRITE;
 330         TPM_CHECK(tpm_nv_define_space(dev, INDEX1, perm, 2 * sizeof(uint32_t)));
 331         TPM_CHECK(tpm_nv_define_space(dev, INDEX1, perm, sizeof(uint32_t)));
 332
 333         /* Sets the global lock */
 334         tpm_set_global_lock(dev);
 335
 336         /* Verifies that index0 cannot be redefined */
 337         result = tpm_nv_define_space(dev, INDEX0, perm, sizeof(uint32_t));
 338         assert(result == TPM_AREA_LOCKED);
 339
 340         /* Checks that index1 can */
 341         TPM_CHECK(tpm_nv_define_space(dev, INDEX1, perm, 2 * sizeof(uint32_t)));
 342         TPM_CHECK(tpm_nv_define_space(dev, INDEX1, perm, sizeof(uint32_t)));
 343
 344         /* Turns off PP */
 345         tpm_tsc_physical_presence(dev, PHYS_PRESENCE);
 346
 347         /* Verifies that neither index0 nor index1 can be redefined */
 348         result = tpm_nv_define_space(dev, INDEX0, perm, sizeof(uint32_t));
 349         assert(result == TPM_BAD_PRESENCE);
 350         result = tpm_nv_define_space(dev, INDEX1, perm, sizeof(uint32_t));
 351         assert(result == TPM_BAD_PRESENCE);
 352
 353         printf("done\n");
 354         return 0;
 355 }
 356
 357 #define PERMPPGL (TPM_NV_PER_PPWRITE | TPM_NV_PER_GLOBALLOCK)
 358 #define PERMPP TPM_NV_PER_PPWRITE
 359
 360 static int test_space_perm(struct udevice *dev)
 361 {
 362         uint32_t perm;
 363
 364         printf("Testing spaceperm ...");
 365         tpm_init(dev);
 366         TPM_CHECK(TlclStartupIfNeeded(dev));
 367         TPM_CHECK(tpm_continue_self_test(dev));
 368         TPM_CHECK(tpm_tsc_physical_presence(dev, PRESENCE));
 369         TPM_CHECK(tpm_get_permissions(dev, INDEX0, &perm));
 370         assert((perm & PERMPPGL) == PERMPPGL);
 371         TPM_CHECK(tpm_get_permissions(dev, INDEX1, &perm));
 372         assert((perm & PERMPP) == PERMPP);
 373         printf("done\n");
 374         return 0;
 375 }
 376
 377 static int test_startup(struct udevice *dev)
 378 {
 379         uint32_t result;
 380
 381         printf("Testing startup ...\n");
 382
 383         tpm_init(dev);
 384         result = tpm_startup(dev, TPM_ST_CLEAR);
 385         if (result != 0 && result != TPM_INVALID_POSTINIT)
 386                 printf("\ttpm startup failed with 0x%x\n", result);
 387         result = tpm_get_flags(dev, NULL, NULL, NULL);
 388         if (result != 0)
 389                 printf("\ttpm getflags failed with 0x%x\n", result);
 390         printf("\texecuting SelfTestFull\n");
 391         tpm_self_test_full(dev);
 392         result = tpm_get_flags(dev, NULL, NULL, NULL);
 393         if (result != 0)
 394                 printf("\ttpm getflags failed with 0x%x\n", result);
 395         printf("\tdone\n");
 396         return 0;
 397 }
 398
 399 /*
 400  * Runs [op] and ensures it returns success and doesn't run longer than
 401  * [time_limit] in milliseconds.
 402  */
 403 #define TTPM_CHECK(op, time_limit) do { \
 404         ulong start, time; \
 405         uint32_t __result; \
 406         \
 407         start = get_timer(0); \
 408         __result = op; \
 409         if (__result != TPM_SUCCESS) { \
 410                 printf("\t" #op ": error 0x%x\n", __result); \
 411                 return -1; \
 412         } \
 413         time = get_timer(start); \
 414         printf("\t" #op ": %lu ms\n", time); \
 415         if (time > (ulong)time_limit) { \
 416                 printf("\t" #op " exceeded " #time_limit " ms\n"); \
 417         } \
 418 } while (0)
 419
 420
 421 static int test_timing(struct udevice *dev)
 422 {
 423         uint8_t in[20], out[20];
 424         uint32_t x;
 425
 426         printf("Testing timing ...");
 427         tpm_init(dev);
 428         TTPM_CHECK(TlclStartupIfNeeded(dev), 50);
 429         TTPM_CHECK(tpm_continue_self_test(dev), 100);
 430         TTPM_CHECK(tpm_self_test_full(dev), 1000);
 431         TTPM_CHECK(tpm_tsc_physical_presence(dev, PRESENCE), 100);
 432         TTPM_CHECK(tpm_nv_write_value(dev, INDEX0, (uint8_t *)&x, sizeof(x)),
 433                    100);
 434         TTPM_CHECK(tpm_nv_read_value(dev, INDEX0, (uint8_t *)&x, sizeof(x)),
 435                    100);
 436         TTPM_CHECK(tpm_extend(dev, 0, in, out), 200);
 437         TTPM_CHECK(tpm_set_global_lock(dev), 50);
 438         TTPM_CHECK(tpm_tsc_physical_presence(dev, PHYS_PRESENCE), 100);
 439         printf("done\n");
 440         return 0;
 441 }
 442
 443 #define TPM_MAX_NV_WRITES_NOOWNER 64
 444
 445 static int test_write_limit(struct udevice *dev)
 446 {
 447         uint32_t result;
 448         int i;
 449
 450         printf("Testing writelimit ...\n");
 451         tpm_init(dev);
 452         TPM_CHECK(TlclStartupIfNeeded(dev));
 453         TPM_CHECK(tpm_self_test_full(dev));
 454         TPM_CHECK(tpm_tsc_physical_presence(dev, PRESENCE));
 455         TPM_CHECK(tpm_force_clear(dev));
 456         TPM_CHECK(tpm_physical_enable(dev));
 457         TPM_CHECK(tpm_physical_set_deactivated(dev, 0));
 458
 459         for (i = 0; i < TPM_MAX_NV_WRITES_NOOWNER + 2; i++) {
 460                 printf("\twriting %d\n", i);
 461                 result = tpm_nv_write_value(dev, INDEX0, (uint8_t *)&i,
 462                                             sizeof(i));
 463                 switch (result) {
 464                 case TPM_SUCCESS:
 465                         break;
 466                 case TPM_MAXNVWRITES:
 467                         assert(i >= TPM_MAX_NV_WRITES_NOOWNER);
 468                 default:
 469                         pr_err("\tunexpected error code %d (0x%x)\n",
 470                               result, result);
 471                 }
 472         }
 473
 474         /* Reset write count */
 475         TPM_CHECK(tpm_force_clear(dev));
 476         TPM_CHECK(tpm_physical_enable(dev));
 477         TPM_CHECK(tpm_physical_set_deactivated(dev, 0));
 478
 479         /* Try writing again. */
 480         TPM_CHECK(tpm_nv_write_value(dev, INDEX0, (uint8_t *)&i, sizeof(i)));
 481         printf("\tdone\n");
 482         return 0;
 483 }
 484
 485 #define VOIDTEST(XFUNC) \
 486         int do_test_##XFUNC(cmd_tbl_t *cmd_tbl, int flag, int argc, \
 487         char * const argv[]) \
 488         { \
 489                 struct udevice *dev; \
 490                 int ret; \
 491 \
 492                 ret = get_tpm(&dev); \
 493                 if (ret) \
 494                         return ret; \
 495                 return test_##XFUNC(dev); \
 496         }
 497
 498 #define VOIDENT(XNAME) \
 499         U_BOOT_CMD_MKENT(XNAME, 0, 1, do_test_##XNAME, "", ""),
 500
 501 VOIDTEST(early_extend)
 502 VOIDTEST(early_nvram)
 503 VOIDTEST(early_nvram2)
 504 VOIDTEST(enable)
 505 VOIDTEST(fast_enable)
 506 VOIDTEST(global_lock)
 507 VOIDTEST(lock)
 508 VOIDTEST(readonly)
 509 VOIDTEST(redefine_unowned)
 510 VOIDTEST(space_perm)
 511 VOIDTEST(startup)
 512 VOIDTEST(timing)
 513 VOIDTEST(write_limit)
 514 VOIDTEST(timer)
 515
 516 static cmd_tbl_t cmd_cros_tpm_sub[] = {
 517         VOIDENT(early_extend)
 518         VOIDENT(early_nvram)
 519         VOIDENT(early_nvram2)
 520         VOIDENT(enable)
 521         VOIDENT(fast_enable)
 522         VOIDENT(global_lock)
 523         VOIDENT(lock)
 524         VOIDENT(readonly)
 525         VOIDENT(redefine_unowned)
 526         VOIDENT(space_perm)
 527         VOIDENT(startup)
 528         VOIDENT(timing)
 529         VOIDENT(write_limit)
 530         VOIDENT(timer)
 531 };
 532
 533 static int do_tpmtest(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 534 {
 535         cmd_tbl_t *c;
 536         int i;
 537
 538         printf("argc = %d, argv = ", argc);
 539
 540         for (i = 0; i < argc; i++)
 541                 printf(" %s", argv[i]);
 542
 543         printf("\n------\n");
 544
 545         argc--;
 546         argv++;
 547         c = find_cmd_tbl(argv[0], cmd_cros_tpm_sub,
 548                          ARRAY_SIZE(cmd_cros_tpm_sub));
 549         return c ? c->cmd(cmdtp, flag, argc, argv) : cmd_usage(cmdtp);
 550 }
 551
 552 U_BOOT_CMD(tpmtest, 2, 1, do_tpmtest, "TPM tests",
 553         "\n\tearly_extend\n"
 554         "\tearly_nvram\n"
 555         "\tearly_nvram2\n"
 556         "\tenable\n"
 557         "\tfast_enable\n"
 558         "\tglobal_lock\n"
 559         "\tlock\n"
 560         "\treadonly\n"
 561         "\tredefine_unowned\n"
 562         "\tspace_perm\n"
 563         "\tstartup\n"
 564         "\ttiming\n"
 565         "\twrite_limit\n");