arch/x86/kernel/tboot.c

   1 /*
   2  * tboot.c: main implementation of helper functions used by kernel for
   3  *          runtime support of Intel(R) Trusted Execution Technology
   4  *
   5  * Copyright (c) 2006-2009, Intel Corporation
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms and conditions of the GNU General Public License,
   9  * version 2, as published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14  * more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along with
  17  * this program; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  */
  21
  22 #include <linux/dma_remapping.h>
  23 #include <linux/init_task.h>
  24 #include <linux/spinlock.h>
  25 #include <linux/export.h>
  26 #include <linux/delay.h>
  27 #include <linux/sched.h>
  28 #include <linux/init.h>
  29 #include <linux/dmar.h>
  30 #include <linux/cpu.h>
  31 #include <linux/pfn.h>
  32 #include <linux/mm.h>
  33 #include <linux/tboot.h>
  34 #include <linux/debugfs.h>
  35
  36 #include <asm/realmode.h>
  37 #include <asm/processor.h>
  38 #include <asm/bootparam.h>
  39 #include <asm/pgtable.h>
  40 #include <asm/pgalloc.h>
  41 #include <asm/swiotlb.h>
  42 #include <asm/fixmap.h>
  43 #include <asm/proto.h>
  44 #include <asm/setup.h>
  45 #include <asm/e820.h>
  46 #include <asm/io.h>
  47
  48 #include "../realmode/rm/wakeup.h"
  49
  50 /* Global pointer to shared data; NULL means no measured launch. */
  51 struct tboot *tboot __read_mostly;
  52 EXPORT_SYMBOL(tboot);
  53
  54 /* timeout for APs (in secs) to enter wait-for-SIPI state during shutdown */
  55 #define AP_WAIT_TIMEOUT         1
  56
  57 #undef pr_fmt
  58 #define pr_fmt(fmt)     "tboot: " fmt
  59
  60 static u8 tboot_uuid[16] __initdata = TBOOT_UUID;
  61
  62 void __init tboot_probe(void)
  63 {
  64         /* Look for valid page-aligned address for shared page. */
  65         if (!boot_params.tboot_addr)
  66                 return;
  67         /*
  68          * also verify that it is mapped as we expect it before calling
  69          * set_fixmap(), to reduce chance of garbage value causing crash
  70          */
  71         if (!e820_any_mapped(boot_params.tboot_addr,
  72                              boot_params.tboot_addr, E820_RESERVED)) {
  73                 pr_warning("non-0 tboot_addr but it is not of type E820_RESERVED\n");
  74                 return;
  75         }
  76
  77         /* only a natively booted kernel should be using TXT */
  78         if (paravirt_enabled()) {
  79                 pr_warning("non-0 tboot_addr but pv_ops is enabled\n");
  80                 return;
  81         }
  82
  83         /* Map and check for tboot UUID. */
  84         set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
  85         tboot = (struct tboot *)fix_to_virt(FIX_TBOOT_BASE);
  86         if (memcmp(&tboot_uuid, &tboot->uuid, sizeof(tboot->uuid))) {
  87                 pr_warning("tboot at 0x%llx is invalid\n",
  88                            boot_params.tboot_addr);
  89                 tboot = NULL;
  90                 return;
  91         }
  92         if (tboot->version < 5) {
  93                 pr_warning("tboot version is invalid: %u\n", tboot->version);
  94                 tboot = NULL;
  95                 return;
  96         }
  97
  98         pr_info("found shared page at phys addr 0x%llx:\n",
  99                 boot_params.tboot_addr);
 100         pr_debug("version: %d\n", tboot->version);
 101         pr_debug("log_addr: 0x%08x\n", tboot->log_addr);
 102         pr_debug("shutdown_entry: 0x%x\n", tboot->shutdown_entry);
 103         pr_debug("tboot_base: 0x%08x\n", tboot->tboot_base);
 104         pr_debug("tboot_size: 0x%x\n", tboot->tboot_size);
 105 }
 106
 107 static pgd_t *tboot_pg_dir;
 108 static struct mm_struct tboot_mm = {
 109         .mm_rb          = RB_ROOT,
 110         .pgd            = swapper_pg_dir,
 111         .mm_users       = ATOMIC_INIT(2),
 112         .mm_count       = ATOMIC_INIT(1),
 113         .mmap_sem       = __RWSEM_INITIALIZER(init_mm.mmap_sem),
 114         .page_table_lock =  __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
 115         .mmlist         = LIST_HEAD_INIT(init_mm.mmlist),
 116 };
 117
 118 static inline void switch_to_tboot_pt(void)
 119 {
 120         write_cr3(virt_to_phys(tboot_pg_dir));
 121 }
 122
 123 static int map_tboot_page(unsigned long vaddr, unsigned long pfn,
 124                           pgprot_t prot)
 125 {
 126         pgd_t *pgd;
 127         pud_t *pud;
 128         pmd_t *pmd;
 129         pte_t *pte;
 130
 131         pgd = pgd_offset(&tboot_mm, vaddr);
 132         pud = pud_alloc(&tboot_mm, pgd, vaddr);
 133         if (!pud)
 134                 return -1;
 135         pmd = pmd_alloc(&tboot_mm, pud, vaddr);
 136         if (!pmd)
 137                 return -1;
 138         pte = pte_alloc_map(&tboot_mm, NULL, pmd, vaddr);
 139         if (!pte)
 140                 return -1;
 141         set_pte_at(&tboot_mm, vaddr, pte, pfn_pte(pfn, prot));
 142         pte_unmap(pte);
 143         return 0;
 144 }
 145
 146 static int map_tboot_pages(unsigned long vaddr, unsigned long start_pfn,
 147                            unsigned long nr)
 148 {
 149         /* Reuse the original kernel mapping */
 150         tboot_pg_dir = pgd_alloc(&tboot_mm);
 151         if (!tboot_pg_dir)
 152                 return -1;
 153
 154         for (; nr > 0; nr--, vaddr += PAGE_SIZE, start_pfn++) {
 155                 if (map_tboot_page(vaddr, start_pfn, PAGE_KERNEL_EXEC))
 156                         return -1;
 157         }
 158
 159         return 0;
 160 }
 161
 162 static void tboot_create_trampoline(void)
 163 {
 164         u32 map_base, map_size;
 165
 166         /* Create identity map for tboot shutdown code. */
 167         map_base = PFN_DOWN(tboot->tboot_base);
 168         map_size = PFN_UP(tboot->tboot_size);
 169         if (map_tboot_pages(map_base << PAGE_SHIFT, map_base, map_size))
 170                 panic("tboot: Error mapping tboot pages (mfns) @ 0x%x, 0x%x\n",
 171                       map_base, map_size);
 172 }
 173
 174 #ifdef CONFIG_ACPI_SLEEP
 175
 176 static void add_mac_region(phys_addr_t start, unsigned long size)
 177 {
 178         struct tboot_mac_region *mr;
 179         phys_addr_t end = start + size;
 180
 181         if (tboot->num_mac_regions >= MAX_TB_MAC_REGIONS)
 182                 panic("tboot: Too many MAC regions\n");
 183
 184         if (start && size) {
 185                 mr = &tboot->mac_regions[tboot->num_mac_regions++];
 186                 mr->start = round_down(start, PAGE_SIZE);
 187                 mr->size  = round_up(end, PAGE_SIZE) - mr->start;
 188         }
 189 }
 190
 191 static int tboot_setup_sleep(void)
 192 {
 193         int i;
 194
 195         tboot->num_mac_regions = 0;
 196
 197         for (i = 0; i < e820.nr_map; i++) {
 198                 if ((e820.map[i].type != E820_RAM)
 199                  && (e820.map[i].type != E820_RESERVED_KERN))
 200                         continue;
 201
 202                 add_mac_region(e820.map[i].addr, e820.map[i].size);
 203         }
 204
 205         tboot->acpi_sinfo.kernel_s3_resume_vector =
 206                 real_mode_header->wakeup_start;
 207
 208         return 0;
 209 }
 210
 211 #else /* no CONFIG_ACPI_SLEEP */
 212
 213 static int tboot_setup_sleep(void)
 214 {
 215         /* S3 shutdown requested, but S3 not supported by the kernel... */
 216         BUG();
 217         return -1;
 218 }
 219
 220 #endif
 221
 222 void tboot_shutdown(u32 shutdown_type)
 223 {
 224         void (*shutdown)(void);
 225
 226         if (!tboot_enabled())
 227                 return;
 228
 229         /*
 230          * if we're being called before the 1:1 mapping is set up then just
 231          * return and let the normal shutdown happen; this should only be
 232          * due to very early panic()
 233          */
 234         if (!tboot_pg_dir)
 235                 return;
 236
 237         /* if this is S3 then set regions to MAC */
 238         if (shutdown_type == TB_SHUTDOWN_S3)
 239                 if (tboot_setup_sleep())
 240                         return;
 241
 242         tboot->shutdown_type = shutdown_type;
 243
 244         switch_to_tboot_pt();
 245
 246         shutdown = (void(*)(void))(unsigned long)tboot->shutdown_entry;
 247         shutdown();
 248
 249         /* should not reach here */
 250         while (1)
 251                 halt();
 252 }
 253
 254 static void tboot_copy_fadt(const struct acpi_table_fadt *fadt)
 255 {
 256 #define TB_COPY_GAS(tbg, g)                     \
 257         tbg.space_id     = g.space_id;          \
 258         tbg.bit_width    = g.bit_width;         \
 259         tbg.bit_offset   = g.bit_offset;        \
 260         tbg.access_width = g.access_width;      \
 261         tbg.address      = g.address;
 262
 263         TB_COPY_GAS(tboot->acpi_sinfo.pm1a_cnt_blk, fadt->xpm1a_control_block);
 264         TB_COPY_GAS(tboot->acpi_sinfo.pm1b_cnt_blk, fadt->xpm1b_control_block);
 265         TB_COPY_GAS(tboot->acpi_sinfo.pm1a_evt_blk, fadt->xpm1a_event_block);
 266         TB_COPY_GAS(tboot->acpi_sinfo.pm1b_evt_blk, fadt->xpm1b_event_block);
 267
 268         /*
 269          * We need phys addr of waking vector, but can't use virt_to_phys() on
 270          * &acpi_gbl_FACS because it is ioremap'ed, so calc from FACS phys
 271          * addr.
 272          */
 273         tboot->acpi_sinfo.wakeup_vector = fadt->facs +
 274                 offsetof(struct acpi_table_facs, firmware_waking_vector);
 275 }
 276
 277 static int tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control)
 278 {
 279         static u32 acpi_shutdown_map[ACPI_S_STATE_COUNT] = {
 280                 /* S0,1,2: */ -1, -1, -1,
 281                 /* S3: */ TB_SHUTDOWN_S3,
 282                 /* S4: */ TB_SHUTDOWN_S4,
 283                 /* S5: */ TB_SHUTDOWN_S5 };
 284
 285         if (!tboot_enabled())
 286                 return 0;
 287
 288         tboot_copy_fadt(&acpi_gbl_FADT);
 289         tboot->acpi_sinfo.pm1a_cnt_val = pm1a_control;
 290         tboot->acpi_sinfo.pm1b_cnt_val = pm1b_control;
 291         /* we always use the 32b wakeup vector */
 292         tboot->acpi_sinfo.vector_width = 32;
 293
 294         if (sleep_state >= ACPI_S_STATE_COUNT ||
 295             acpi_shutdown_map[sleep_state] == -1) {
 296                 pr_warning("unsupported sleep state 0x%x\n", sleep_state);
 297                 return -1;
 298         }
 299
 300         tboot_shutdown(acpi_shutdown_map[sleep_state]);
 301         return 0;
 302 }
 303
 304 static atomic_t ap_wfs_count;
 305
 306 static int tboot_wait_for_aps(int num_aps)
 307 {
 308         unsigned long timeout;
 309
 310         timeout = AP_WAIT_TIMEOUT*HZ;
 311         while (atomic_read((atomic_t *)&tboot->num_in_wfs) != num_aps &&
 312                timeout) {
 313                 mdelay(1);
 314                 timeout--;
 315         }
 316
 317         if (timeout)
 318                 pr_warning("tboot wait for APs timeout\n");
 319
 320         return !(atomic_read((atomic_t *)&tboot->num_in_wfs) == num_aps);
 321 }
 322
 323 static int tboot_cpu_callback(struct notifier_block *nfb, unsigned long action,
 324                               void *hcpu)
 325 {
 326         switch (action) {
 327         case CPU_DYING:
 328                 atomic_inc(&ap_wfs_count);
 329                 if (num_online_cpus() == 1)
 330                         if (tboot_wait_for_aps(atomic_read(&ap_wfs_count)))
 331                                 return NOTIFY_BAD;
 332                 break;
 333         }
 334         return NOTIFY_OK;
 335 }
 336
 337 static struct notifier_block tboot_cpu_notifier =
 338 {
 339         .notifier_call = tboot_cpu_callback,
 340 };
 341
 342 #ifdef CONFIG_DEBUG_FS
 343
 344 #define TBOOT_LOG_UUID  { 0x26, 0x25, 0x19, 0xc0, 0x30, 0x6b, 0xb4, 0x4d, \
 345                           0x4c, 0x84, 0xa3, 0xe9, 0x53, 0xb8, 0x81, 0x74 }
 346
 347 #define TBOOT_SERIAL_LOG_ADDR   0x60000
 348 #define TBOOT_SERIAL_LOG_SIZE   0x08000
 349 #define LOG_MAX_SIZE_OFF        16
 350 #define LOG_BUF_OFF             24
 351
 352 static uint8_t tboot_log_uuid[16] = TBOOT_LOG_UUID;
 353
 354 static ssize_t tboot_log_read(struct file *file, char __user *user_buf, size_t count, loff_t *ppos)
 355 {
 356         void __iomem *log_base;
 357         u8 log_uuid[16];
 358         u32 max_size;
 359         void *kbuf;
 360         int ret = -EFAULT;
 361
 362         log_base = ioremap_nocache(TBOOT_SERIAL_LOG_ADDR, TBOOT_SERIAL_LOG_SIZE);
 363         if (!log_base)
 364                 return ret;
 365
 366         memcpy_fromio(log_uuid, log_base, sizeof(log_uuid));
 367         if (memcmp(&tboot_log_uuid, log_uuid, sizeof(log_uuid)))
 368                 goto err_iounmap;
 369
 370         max_size = readl(log_base + LOG_MAX_SIZE_OFF);
 371         if (*ppos >= max_size) {
 372                 ret = 0;
 373                 goto err_iounmap;
 374         }
 375
 376         if (*ppos + count > max_size)
 377                 count = max_size - *ppos;
 378
 379         kbuf = kmalloc(count, GFP_KERNEL);
 380         if (!kbuf) {
 381                 ret = -ENOMEM;
 382                 goto err_iounmap;
 383         }
 384
 385         memcpy_fromio(kbuf, log_base + LOG_BUF_OFF + *ppos, count);
 386         if (copy_to_user(user_buf, kbuf, count))
 387                 goto err_kfree;
 388
 389         *ppos += count;
 390
 391         ret = count;
 392
 393 err_kfree:
 394         kfree(kbuf);
 395
 396 err_iounmap:
 397         iounmap(log_base);
 398
 399         return ret;
 400 }
 401
 402 static const struct file_operations tboot_log_fops = {
 403         .read   = tboot_log_read,
 404         .llseek = default_llseek,
 405 };
 406
 407 #endif /* CONFIG_DEBUG_FS */
 408
 409 static __init int tboot_late_init(void)
 410 {
 411         if (!tboot_enabled())
 412                 return 0;
 413
 414         tboot_create_trampoline();
 415
 416         atomic_set(&ap_wfs_count, 0);
 417         register_hotcpu_notifier(&tboot_cpu_notifier);
 418
 419 #ifdef CONFIG_DEBUG_FS
 420         debugfs_create_file("tboot_log", S_IRUSR,
 421                         arch_debugfs_dir, NULL, &tboot_log_fops);
 422 #endif
 423
 424         acpi_os_set_prepare_sleep(&tboot_sleep);
 425         return 0;
 426 }
 427
 428 late_initcall(tboot_late_init);
 429
 430 /*
 431  * TXT configuration registers (offsets from TXT_{PUB, PRIV}_CONFIG_REGS_BASE)
 432  */
 433
 434 #define TXT_PUB_CONFIG_REGS_BASE       0xfed30000
 435 #define TXT_PRIV_CONFIG_REGS_BASE      0xfed20000
 436
 437 /* # pages for each config regs space - used by fixmap */
 438 #define NR_TXT_CONFIG_PAGES     ((TXT_PUB_CONFIG_REGS_BASE -                \
 439                                   TXT_PRIV_CONFIG_REGS_BASE) >> PAGE_SHIFT)
 440
 441 /* offsets from pub/priv config space */
 442 #define TXTCR_HEAP_BASE             0x0300
 443 #define TXTCR_HEAP_SIZE             0x0308
 444
 445 #define SHA1_SIZE      20
 446
 447 struct sha1_hash {
 448         u8 hash[SHA1_SIZE];
 449 };
 450
 451 struct sinit_mle_data {
 452         u32               version;             /* currently 6 */
 453         struct sha1_hash  bios_acm_id;
 454         u32               edx_senter_flags;
 455         u64               mseg_valid;
 456         struct sha1_hash  sinit_hash;
 457         struct sha1_hash  mle_hash;
 458         struct sha1_hash  stm_hash;
 459         struct sha1_hash  lcp_policy_hash;
 460         u32               lcp_policy_control;
 461         u32               rlp_wakeup_addr;
 462         u32               reserved;
 463         u32               num_mdrs;
 464         u32               mdrs_off;
 465         u32               num_vtd_dmars;
 466         u32               vtd_dmars_off;
 467 } __packed;
 468
 469 struct acpi_table_header *tboot_get_dmar_table(struct acpi_table_header *dmar_tbl)
 470 {
 471         void *heap_base, *heap_ptr, *config;
 472
 473         if (!tboot_enabled())
 474                 return dmar_tbl;
 475
 476         /*
 477          * ACPI tables may not be DMA protected by tboot, so use DMAR copy
 478          * SINIT saved in SinitMleData in TXT heap (which is DMA protected)
 479          */
 480
 481         /* map config space in order to get heap addr */
 482         config = ioremap(TXT_PUB_CONFIG_REGS_BASE, NR_TXT_CONFIG_PAGES *
 483                          PAGE_SIZE);
 484         if (!config)
 485                 return NULL;
 486
 487         /* now map TXT heap */
 488         heap_base = ioremap(*(u64 *)(config + TXTCR_HEAP_BASE),
 489                             *(u64 *)(config + TXTCR_HEAP_SIZE));
 490         iounmap(config);
 491         if (!heap_base)
 492                 return NULL;
 493
 494         /* walk heap to SinitMleData */
 495         /* skip BiosData */
 496         heap_ptr = heap_base + *(u64 *)heap_base;
 497         /* skip OsMleData */
 498         heap_ptr += *(u64 *)heap_ptr;
 499         /* skip OsSinitData */
 500         heap_ptr += *(u64 *)heap_ptr;
 501         /* now points to SinitMleDataSize; set to SinitMleData */
 502         heap_ptr += sizeof(u64);
 503         /* get addr of DMAR table */
 504         dmar_tbl = (struct acpi_table_header *)(heap_ptr +
 505                    ((struct sinit_mle_data *)heap_ptr)->vtd_dmars_off -
 506                    sizeof(u64));
 507
 508         /* don't unmap heap because dmar.c needs access to this */
 509
 510         return dmar_tbl;
 511 }
 512
 513 int tboot_force_iommu(void)
 514 {
 515         if (!tboot_enabled())
 516                 return 0;
 517
 518         if (no_iommu || swiotlb || dmar_disabled)
 519                 pr_warning("Forcing Intel-IOMMU to enabled\n");
 520
 521         dmar_disabled = 0;
 522 #ifdef CONFIG_SWIOTLB
 523         swiotlb = 0;
 524 #endif
 525         no_iommu = 0;
 526
 527         return 1;
 528 }