arch/x86/kernel/tboot.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * tboot.c: main implementation of helper functions used by kernel for
   4  *          runtime support of Intel(R) Trusted Execution Technology
   5  *
   6  * Copyright (c) 2006-2009, Intel Corporation
   7  */
   8
   9 #include <linux/intel-iommu.h>
  10 #include <linux/init_task.h>
  11 #include <linux/spinlock.h>
  12 #include <linux/export.h>
  13 #include <linux/delay.h>
  14 #include <linux/sched.h>
  15 #include <linux/init.h>
  16 #include <linux/dmar.h>
  17 #include <linux/cpu.h>
  18 #include <linux/pfn.h>
  19 #include <linux/mm.h>
  20 #include <linux/tboot.h>
  21 #include <linux/debugfs.h>
  22
  23 #include <asm/realmode.h>
  24 #include <asm/processor.h>
  25 #include <asm/bootparam.h>
  26 #include <asm/pgtable.h>
  27 #include <asm/pgalloc.h>
  28 #include <asm/swiotlb.h>
  29 #include <asm/fixmap.h>
  30 #include <asm/proto.h>
  31 #include <asm/setup.h>
  32 #include <asm/e820/api.h>
  33 #include <asm/io.h>
  34
  35 #include "../realmode/rm/wakeup.h"
  36
  37 /* Global pointer to shared data; NULL means no measured launch. */
  38 struct tboot *tboot __read_mostly;
  39 EXPORT_SYMBOL(tboot);
  40
  41 /* timeout for APs (in secs) to enter wait-for-SIPI state during shutdown */
  42 #define AP_WAIT_TIMEOUT         1
  43
  44 #undef pr_fmt
  45 #define pr_fmt(fmt)     "tboot: " fmt
  46
  47 static u8 tboot_uuid[16] __initdata = TBOOT_UUID;
  48
  49 void __init tboot_probe(void)
  50 {
  51         /* Look for valid page-aligned address for shared page. */
  52         if (!boot_params.tboot_addr)
  53                 return;
  54         /*
  55          * also verify that it is mapped as we expect it before calling
  56          * set_fixmap(), to reduce chance of garbage value causing crash
  57          */
  58         if (!e820__mapped_any(boot_params.tboot_addr,
  59                              boot_params.tboot_addr, E820_TYPE_RESERVED)) {
  60                 pr_warning("non-0 tboot_addr but it is not of type E820_TYPE_RESERVED\n");
  61                 return;
  62         }
  63
  64         /* Map and check for tboot UUID. */
  65         set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
  66         tboot = (struct tboot *)fix_to_virt(FIX_TBOOT_BASE);
  67         if (memcmp(&tboot_uuid, &tboot->uuid, sizeof(tboot->uuid))) {
  68                 pr_warning("tboot at 0x%llx is invalid\n",
  69                            boot_params.tboot_addr);
  70                 tboot = NULL;
  71                 return;
  72         }
  73         if (tboot->version < 5) {
  74                 pr_warning("tboot version is invalid: %u\n", tboot->version);
  75                 tboot = NULL;
  76                 return;
  77         }
  78
  79         pr_info("found shared page at phys addr 0x%llx:\n",
  80                 boot_params.tboot_addr);
  81         pr_debug("version: %d\n", tboot->version);
  82         pr_debug("log_addr: 0x%08x\n", tboot->log_addr);
  83         pr_debug("shutdown_entry: 0x%x\n", tboot->shutdown_entry);
  84         pr_debug("tboot_base: 0x%08x\n", tboot->tboot_base);
  85         pr_debug("tboot_size: 0x%x\n", tboot->tboot_size);
  86 }
  87
  88 static pgd_t *tboot_pg_dir;
  89 static struct mm_struct tboot_mm = {
  90         .mm_rb          = RB_ROOT,
  91         .pgd            = swapper_pg_dir,
  92         .mm_users       = ATOMIC_INIT(2),
  93         .mm_count       = ATOMIC_INIT(1),
  94         .mmap_sem       = __RWSEM_INITIALIZER(init_mm.mmap_sem),
  95         .page_table_lock =  __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
  96         .mmlist         = LIST_HEAD_INIT(init_mm.mmlist),
  97 };
  98
  99 static inline void switch_to_tboot_pt(void)
 100 {
 101         write_cr3(virt_to_phys(tboot_pg_dir));
 102 }
 103
 104 static int map_tboot_page(unsigned long vaddr, unsigned long pfn,
 105                           pgprot_t prot)
 106 {
 107         pgd_t *pgd;
 108         p4d_t *p4d;
 109         pud_t *pud;
 110         pmd_t *pmd;
 111         pte_t *pte;
 112
 113         pgd = pgd_offset(&tboot_mm, vaddr);
 114         p4d = p4d_alloc(&tboot_mm, pgd, vaddr);
 115         if (!p4d)
 116                 return -1;
 117         pud = pud_alloc(&tboot_mm, p4d, vaddr);
 118         if (!pud)
 119                 return -1;
 120         pmd = pmd_alloc(&tboot_mm, pud, vaddr);
 121         if (!pmd)
 122                 return -1;
 123         pte = pte_alloc_map(&tboot_mm, pmd, vaddr);
 124         if (!pte)
 125                 return -1;
 126         set_pte_at(&tboot_mm, vaddr, pte, pfn_pte(pfn, prot));
 127         pte_unmap(pte);
 128
 129         /*
 130          * PTI poisons low addresses in the kernel page tables in the
 131          * name of making them unusable for userspace.  To execute
 132          * code at such a low address, the poison must be cleared.
 133          *
 134          * Note: 'pgd' actually gets set in p4d_alloc() _or_
 135          * pud_alloc() depending on 4/5-level paging.
 136          */
 137         pgd->pgd &= ~_PAGE_NX;
 138
 139         return 0;
 140 }
 141
 142 static int map_tboot_pages(unsigned long vaddr, unsigned long start_pfn,
 143                            unsigned long nr)
 144 {
 145         /* Reuse the original kernel mapping */
 146         tboot_pg_dir = pgd_alloc(&tboot_mm);
 147         if (!tboot_pg_dir)
 148                 return -1;
 149
 150         for (; nr > 0; nr--, vaddr += PAGE_SIZE, start_pfn++) {
 151                 if (map_tboot_page(vaddr, start_pfn, PAGE_KERNEL_EXEC))
 152                         return -1;
 153         }
 154
 155         return 0;
 156 }
 157
 158 static void tboot_create_trampoline(void)
 159 {
 160         u32 map_base, map_size;
 161
 162         /* Create identity map for tboot shutdown code. */
 163         map_base = PFN_DOWN(tboot->tboot_base);
 164         map_size = PFN_UP(tboot->tboot_size);
 165         if (map_tboot_pages(map_base << PAGE_SHIFT, map_base, map_size))
 166                 panic("tboot: Error mapping tboot pages (mfns) @ 0x%x, 0x%x\n",
 167                       map_base, map_size);
 168 }
 169
 170 #ifdef CONFIG_ACPI_SLEEP
 171
 172 static void add_mac_region(phys_addr_t start, unsigned long size)
 173 {
 174         struct tboot_mac_region *mr;
 175         phys_addr_t end = start + size;
 176
 177         if (tboot->num_mac_regions >= MAX_TB_MAC_REGIONS)
 178                 panic("tboot: Too many MAC regions\n");
 179
 180         if (start && size) {
 181                 mr = &tboot->mac_regions[tboot->num_mac_regions++];
 182                 mr->start = round_down(start, PAGE_SIZE);
 183                 mr->size  = round_up(end, PAGE_SIZE) - mr->start;
 184         }
 185 }
 186
 187 static int tboot_setup_sleep(void)
 188 {
 189         int i;
 190
 191         tboot->num_mac_regions = 0;
 192
 193         for (i = 0; i < e820_table->nr_entries; i++) {
 194                 if ((e820_table->entries[i].type != E820_TYPE_RAM)
 195                  && (e820_table->entries[i].type != E820_TYPE_RESERVED_KERN))
 196                         continue;
 197
 198                 add_mac_region(e820_table->entries[i].addr, e820_table->entries[i].size);
 199         }
 200
 201         tboot->acpi_sinfo.kernel_s3_resume_vector =
 202                 real_mode_header->wakeup_start;
 203
 204         return 0;
 205 }
 206
 207 #else /* no CONFIG_ACPI_SLEEP */
 208
 209 static int tboot_setup_sleep(void)
 210 {
 211         /* S3 shutdown requested, but S3 not supported by the kernel... */
 212         BUG();
 213         return -1;
 214 }
 215
 216 #endif
 217
 218 void tboot_shutdown(u32 shutdown_type)
 219 {
 220         void (*shutdown)(void);
 221
 222         if (!tboot_enabled())
 223                 return;
 224
 225         /*
 226          * if we're being called before the 1:1 mapping is set up then just
 227          * return and let the normal shutdown happen; this should only be
 228          * due to very early panic()
 229          */
 230         if (!tboot_pg_dir)
 231                 return;
 232
 233         /* if this is S3 then set regions to MAC */
 234         if (shutdown_type == TB_SHUTDOWN_S3)
 235                 if (tboot_setup_sleep())
 236                         return;
 237
 238         tboot->shutdown_type = shutdown_type;
 239
 240         switch_to_tboot_pt();
 241
 242         shutdown = (void(*)(void))(unsigned long)tboot->shutdown_entry;
 243         shutdown();
 244
 245         /* should not reach here */
 246         while (1)
 247                 halt();
 248 }
 249
 250 static void tboot_copy_fadt(const struct acpi_table_fadt *fadt)
 251 {
 252 #define TB_COPY_GAS(tbg, g)                     \
 253         tbg.space_id     = g.space_id;          \
 254         tbg.bit_width    = g.bit_width;         \
 255         tbg.bit_offset   = g.bit_offset;        \
 256         tbg.access_width = g.access_width;      \
 257         tbg.address      = g.address;
 258
 259         TB_COPY_GAS(tboot->acpi_sinfo.pm1a_cnt_blk, fadt->xpm1a_control_block);
 260         TB_COPY_GAS(tboot->acpi_sinfo.pm1b_cnt_blk, fadt->xpm1b_control_block);
 261         TB_COPY_GAS(tboot->acpi_sinfo.pm1a_evt_blk, fadt->xpm1a_event_block);
 262         TB_COPY_GAS(tboot->acpi_sinfo.pm1b_evt_blk, fadt->xpm1b_event_block);
 263
 264         /*
 265          * We need phys addr of waking vector, but can't use virt_to_phys() on
 266          * &acpi_gbl_FACS because it is ioremap'ed, so calc from FACS phys
 267          * addr.
 268          */
 269         tboot->acpi_sinfo.wakeup_vector = fadt->facs +
 270                 offsetof(struct acpi_table_facs, firmware_waking_vector);
 271 }
 272
 273 static int tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control)
 274 {
 275         static u32 acpi_shutdown_map[ACPI_S_STATE_COUNT] = {
 276                 /* S0,1,2: */ -1, -1, -1,
 277                 /* S3: */ TB_SHUTDOWN_S3,
 278                 /* S4: */ TB_SHUTDOWN_S4,
 279                 /* S5: */ TB_SHUTDOWN_S5 };
 280
 281         if (!tboot_enabled())
 282                 return 0;
 283
 284         tboot_copy_fadt(&acpi_gbl_FADT);
 285         tboot->acpi_sinfo.pm1a_cnt_val = pm1a_control;
 286         tboot->acpi_sinfo.pm1b_cnt_val = pm1b_control;
 287         /* we always use the 32b wakeup vector */
 288         tboot->acpi_sinfo.vector_width = 32;
 289
 290         if (sleep_state >= ACPI_S_STATE_COUNT ||
 291             acpi_shutdown_map[sleep_state] == -1) {
 292                 pr_warning("unsupported sleep state 0x%x\n", sleep_state);
 293                 return -1;
 294         }
 295
 296         tboot_shutdown(acpi_shutdown_map[sleep_state]);
 297         return 0;
 298 }
 299
 300 static int tboot_extended_sleep(u8 sleep_state, u32 val_a, u32 val_b)
 301 {
 302         if (!tboot_enabled())
 303                 return 0;
 304
 305         pr_warning("tboot is not able to suspend on platforms with reduced hardware sleep (ACPIv5)");
 306         return -ENODEV;
 307 }
 308
 309 static atomic_t ap_wfs_count;
 310
 311 static int tboot_wait_for_aps(int num_aps)
 312 {
 313         unsigned long timeout;
 314
 315         timeout = AP_WAIT_TIMEOUT*HZ;
 316         while (atomic_read((atomic_t *)&tboot->num_in_wfs) != num_aps &&
 317                timeout) {
 318                 mdelay(1);
 319                 timeout--;
 320         }
 321
 322         if (timeout)
 323                 pr_warning("tboot wait for APs timeout\n");
 324
 325         return !(atomic_read((atomic_t *)&tboot->num_in_wfs) == num_aps);
 326 }
 327
 328 static int tboot_dying_cpu(unsigned int cpu)
 329 {
 330         atomic_inc(&ap_wfs_count);
 331         if (num_online_cpus() == 1) {
 332                 if (tboot_wait_for_aps(atomic_read(&ap_wfs_count)))
 333                         return -EBUSY;
 334         }
 335         return 0;
 336 }
 337
 338 #ifdef CONFIG_DEBUG_FS
 339
 340 #define TBOOT_LOG_UUID  { 0x26, 0x25, 0x19, 0xc0, 0x30, 0x6b, 0xb4, 0x4d, \
 341                           0x4c, 0x84, 0xa3, 0xe9, 0x53, 0xb8, 0x81, 0x74 }
 342
 343 #define TBOOT_SERIAL_LOG_ADDR   0x60000
 344 #define TBOOT_SERIAL_LOG_SIZE   0x08000
 345 #define LOG_MAX_SIZE_OFF        16
 346 #define LOG_BUF_OFF             24
 347
 348 static uint8_t tboot_log_uuid[16] = TBOOT_LOG_UUID;
 349
 350 static ssize_t tboot_log_read(struct file *file, char __user *user_buf, size_t count, loff_t *ppos)
 351 {
 352         void __iomem *log_base;
 353         u8 log_uuid[16];
 354         u32 max_size;
 355         void *kbuf;
 356         int ret = -EFAULT;
 357
 358         log_base = ioremap_nocache(TBOOT_SERIAL_LOG_ADDR, TBOOT_SERIAL_LOG_SIZE);
 359         if (!log_base)
 360                 return ret;
 361
 362         memcpy_fromio(log_uuid, log_base, sizeof(log_uuid));
 363         if (memcmp(&tboot_log_uuid, log_uuid, sizeof(log_uuid)))
 364                 goto err_iounmap;
 365
 366         max_size = readl(log_base + LOG_MAX_SIZE_OFF);
 367         if (*ppos >= max_size) {
 368                 ret = 0;
 369                 goto err_iounmap;
 370         }
 371
 372         if (*ppos + count > max_size)
 373                 count = max_size - *ppos;
 374
 375         kbuf = kmalloc(count, GFP_KERNEL);
 376         if (!kbuf) {
 377                 ret = -ENOMEM;
 378                 goto err_iounmap;
 379         }
 380
 381         memcpy_fromio(kbuf, log_base + LOG_BUF_OFF + *ppos, count);
 382         if (copy_to_user(user_buf, kbuf, count))
 383                 goto err_kfree;
 384
 385         *ppos += count;
 386
 387         ret = count;
 388
 389 err_kfree:
 390         kfree(kbuf);
 391
 392 err_iounmap:
 393         iounmap(log_base);
 394
 395         return ret;
 396 }
 397
 398 static const struct file_operations tboot_log_fops = {
 399         .read   = tboot_log_read,
 400         .llseek = default_llseek,
 401 };
 402
 403 #endif /* CONFIG_DEBUG_FS */
 404
 405 static __init int tboot_late_init(void)
 406 {
 407         if (!tboot_enabled())
 408                 return 0;
 409
 410         tboot_create_trampoline();
 411
 412         atomic_set(&ap_wfs_count, 0);
 413         cpuhp_setup_state(CPUHP_AP_X86_TBOOT_DYING, "x86/tboot:dying", NULL,
 414                           tboot_dying_cpu);
 415 #ifdef CONFIG_DEBUG_FS
 416         debugfs_create_file("tboot_log", S_IRUSR,
 417                         arch_debugfs_dir, NULL, &tboot_log_fops);
 418 #endif
 419
 420         acpi_os_set_prepare_sleep(&tboot_sleep);
 421         acpi_os_set_prepare_extended_sleep(&tboot_extended_sleep);
 422         return 0;
 423 }
 424
 425 late_initcall(tboot_late_init);
 426
 427 /*
 428  * TXT configuration registers (offsets from TXT_{PUB, PRIV}_CONFIG_REGS_BASE)
 429  */
 430
 431 #define TXT_PUB_CONFIG_REGS_BASE       0xfed30000
 432 #define TXT_PRIV_CONFIG_REGS_BASE      0xfed20000
 433
 434 /* # pages for each config regs space - used by fixmap */
 435 #define NR_TXT_CONFIG_PAGES     ((TXT_PUB_CONFIG_REGS_BASE -                \
 436                                   TXT_PRIV_CONFIG_REGS_BASE) >> PAGE_SHIFT)
 437
 438 /* offsets from pub/priv config space */
 439 #define TXTCR_HEAP_BASE             0x0300
 440 #define TXTCR_HEAP_SIZE             0x0308
 441
 442 #define SHA1_SIZE      20
 443
 444 struct sha1_hash {
 445         u8 hash[SHA1_SIZE];
 446 };
 447
 448 struct sinit_mle_data {
 449         u32               version;             /* currently 6 */
 450         struct sha1_hash  bios_acm_id;
 451         u32               edx_senter_flags;
 452         u64               mseg_valid;
 453         struct sha1_hash  sinit_hash;
 454         struct sha1_hash  mle_hash;
 455         struct sha1_hash  stm_hash;
 456         struct sha1_hash  lcp_policy_hash;
 457         u32               lcp_policy_control;
 458         u32               rlp_wakeup_addr;
 459         u32               reserved;
 460         u32               num_mdrs;
 461         u32               mdrs_off;
 462         u32               num_vtd_dmars;
 463         u32               vtd_dmars_off;
 464 } __packed;
 465
 466 struct acpi_table_header *tboot_get_dmar_table(struct acpi_table_header *dmar_tbl)
 467 {
 468         void *heap_base, *heap_ptr, *config;
 469
 470         if (!tboot_enabled())
 471                 return dmar_tbl;
 472
 473         /*
 474          * ACPI tables may not be DMA protected by tboot, so use DMAR copy
 475          * SINIT saved in SinitMleData in TXT heap (which is DMA protected)
 476          */
 477
 478         /* map config space in order to get heap addr */
 479         config = ioremap(TXT_PUB_CONFIG_REGS_BASE, NR_TXT_CONFIG_PAGES *
 480                          PAGE_SIZE);
 481         if (!config)
 482                 return NULL;
 483
 484         /* now map TXT heap */
 485         heap_base = ioremap(*(u64 *)(config + TXTCR_HEAP_BASE),
 486                             *(u64 *)(config + TXTCR_HEAP_SIZE));
 487         iounmap(config);
 488         if (!heap_base)
 489                 return NULL;
 490
 491         /* walk heap to SinitMleData */
 492         /* skip BiosData */
 493         heap_ptr = heap_base + *(u64 *)heap_base;
 494         /* skip OsMleData */
 495         heap_ptr += *(u64 *)heap_ptr;
 496         /* skip OsSinitData */
 497         heap_ptr += *(u64 *)heap_ptr;
 498         /* now points to SinitMleDataSize; set to SinitMleData */
 499         heap_ptr += sizeof(u64);
 500         /* get addr of DMAR table */
 501         dmar_tbl = (struct acpi_table_header *)(heap_ptr +
 502                    ((struct sinit_mle_data *)heap_ptr)->vtd_dmars_off -
 503                    sizeof(u64));
 504
 505         /* don't unmap heap because dmar.c needs access to this */
 506
 507         return dmar_tbl;
 508 }
 509
 510 int tboot_force_iommu(void)
 511 {
 512         if (!tboot_enabled())
 513                 return 0;
 514
 515         if (intel_iommu_tboot_noforce)
 516                 return 1;
 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 }