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_warn("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_warn("tboot at 0x%llx is invalid\n", boot_params.tboot_addr);
  69                 tboot = NULL;
  70                 return;
  71         }
  72         if (tboot->version < 5) {
  73                 pr_warn("tboot version is invalid: %u\n", tboot->version);
  74                 tboot = NULL;
  75                 return;
  76         }
  77
  78         pr_info("found shared page at phys addr 0x%llx:\n",
  79                 boot_params.tboot_addr);
  80         pr_debug("version: %d\n", tboot->version);
  81         pr_debug("log_addr: 0x%08x\n", tboot->log_addr);
  82         pr_debug("shutdown_entry: 0x%x\n", tboot->shutdown_entry);
  83         pr_debug("tboot_base: 0x%08x\n", tboot->tboot_base);
  84         pr_debug("tboot_size: 0x%x\n", tboot->tboot_size);
  85 }
  86
  87 static pgd_t *tboot_pg_dir;
  88 static struct mm_struct tboot_mm = {
  89         .mm_rb          = RB_ROOT,
  90         .pgd            = swapper_pg_dir,
  91         .mm_users       = ATOMIC_INIT(2),
  92         .mm_count       = ATOMIC_INIT(1),
  93         .mmap_sem       = __RWSEM_INITIALIZER(init_mm.mmap_sem),
  94         .page_table_lock =  __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
  95         .mmlist         = LIST_HEAD_INIT(init_mm.mmlist),
  96 };
  97
  98 static inline void switch_to_tboot_pt(void)
  99 {
 100         write_cr3(virt_to_phys(tboot_pg_dir));
 101 }
 102
 103 static int map_tboot_page(unsigned long vaddr, unsigned long pfn,
 104                           pgprot_t prot)
 105 {
 106         pgd_t *pgd;
 107         p4d_t *p4d;
 108         pud_t *pud;
 109         pmd_t *pmd;
 110         pte_t *pte;
 111
 112         pgd = pgd_offset(&tboot_mm, vaddr);
 113         p4d = p4d_alloc(&tboot_mm, pgd, vaddr);
 114         if (!p4d)
 115                 return -1;
 116         pud = pud_alloc(&tboot_mm, p4d, vaddr);
 117         if (!pud)
 118                 return -1;
 119         pmd = pmd_alloc(&tboot_mm, pud, vaddr);
 120         if (!pmd)
 121                 return -1;
 122         pte = pte_alloc_map(&tboot_mm, pmd, vaddr);
 123         if (!pte)
 124                 return -1;
 125         set_pte_at(&tboot_mm, vaddr, pte, pfn_pte(pfn, prot));
 126         pte_unmap(pte);
 127
 128         /*
 129          * PTI poisons low addresses in the kernel page tables in the
 130          * name of making them unusable for userspace.  To execute
 131          * code at such a low address, the poison must be cleared.
 132          *
 133          * Note: 'pgd' actually gets set in p4d_alloc() _or_
 134          * pud_alloc() depending on 4/5-level paging.
 135          */
 136         pgd->pgd &= ~_PAGE_NX;
 137
 138         return 0;
 139 }
 140
 141 static int map_tboot_pages(unsigned long vaddr, unsigned long start_pfn,
 142                            unsigned long nr)
 143 {
 144         /* Reuse the original kernel mapping */
 145         tboot_pg_dir = pgd_alloc(&tboot_mm);
 146         if (!tboot_pg_dir)
 147                 return -1;
 148
 149         for (; nr > 0; nr--, vaddr += PAGE_SIZE, start_pfn++) {
 150                 if (map_tboot_page(vaddr, start_pfn, PAGE_KERNEL_EXEC))
 151                         return -1;
 152         }
 153
 154         return 0;
 155 }
 156
 157 static void tboot_create_trampoline(void)
 158 {
 159         u32 map_base, map_size;
 160
 161         /* Create identity map for tboot shutdown code. */
 162         map_base = PFN_DOWN(tboot->tboot_base);
 163         map_size = PFN_UP(tboot->tboot_size);
 164         if (map_tboot_pages(map_base << PAGE_SHIFT, map_base, map_size))
 165                 panic("tboot: Error mapping tboot pages (mfns) @ 0x%x, 0x%x\n",
 166                       map_base, map_size);
 167 }
 168
 169 #ifdef CONFIG_ACPI_SLEEP
 170
 171 static void add_mac_region(phys_addr_t start, unsigned long size)
 172 {
 173         struct tboot_mac_region *mr;
 174         phys_addr_t end = start + size;
 175
 176         if (tboot->num_mac_regions >= MAX_TB_MAC_REGIONS)
 177                 panic("tboot: Too many MAC regions\n");
 178
 179         if (start && size) {
 180                 mr = &tboot->mac_regions[tboot->num_mac_regions++];
 181                 mr->start = round_down(start, PAGE_SIZE);
 182                 mr->size  = round_up(end, PAGE_SIZE) - mr->start;
 183         }
 184 }
 185
 186 static int tboot_setup_sleep(void)
 187 {
 188         int i;
 189
 190         tboot->num_mac_regions = 0;
 191
 192         for (i = 0; i < e820_table->nr_entries; i++) {
 193                 if ((e820_table->entries[i].type != E820_TYPE_RAM)
 194                  && (e820_table->entries[i].type != E820_TYPE_RESERVED_KERN))
 195                         continue;
 196
 197                 add_mac_region(e820_table->entries[i].addr, e820_table->entries[i].size);
 198         }
 199
 200         tboot->acpi_sinfo.kernel_s3_resume_vector =
 201                 real_mode_header->wakeup_start;
 202
 203         return 0;
 204 }
 205
 206 #else /* no CONFIG_ACPI_SLEEP */
 207
 208 static int tboot_setup_sleep(void)
 209 {
 210         /* S3 shutdown requested, but S3 not supported by the kernel... */
 211         BUG();
 212         return -1;
 213 }
 214
 215 #endif
 216
 217 void tboot_shutdown(u32 shutdown_type)
 218 {
 219         void (*shutdown)(void);
 220
 221         if (!tboot_enabled())
 222                 return;
 223
 224         /*
 225          * if we're being called before the 1:1 mapping is set up then just
 226          * return and let the normal shutdown happen; this should only be
 227          * due to very early panic()
 228          */
 229         if (!tboot_pg_dir)
 230                 return;
 231
 232         /* if this is S3 then set regions to MAC */
 233         if (shutdown_type == TB_SHUTDOWN_S3)
 234                 if (tboot_setup_sleep())
 235                         return;
 236
 237         tboot->shutdown_type = shutdown_type;
 238
 239         switch_to_tboot_pt();
 240
 241         shutdown = (void(*)(void))(unsigned long)tboot->shutdown_entry;
 242         shutdown();
 243
 244         /* should not reach here */
 245         while (1)
 246                 halt();
 247 }
 248
 249 static void tboot_copy_fadt(const struct acpi_table_fadt *fadt)
 250 {
 251 #define TB_COPY_GAS(tbg, g)                     \
 252         tbg.space_id     = g.space_id;          \
 253         tbg.bit_width    = g.bit_width;         \
 254         tbg.bit_offset   = g.bit_offset;        \
 255         tbg.access_width = g.access_width;      \
 256         tbg.address      = g.address;
 257
 258         TB_COPY_GAS(tboot->acpi_sinfo.pm1a_cnt_blk, fadt->xpm1a_control_block);
 259         TB_COPY_GAS(tboot->acpi_sinfo.pm1b_cnt_blk, fadt->xpm1b_control_block);
 260         TB_COPY_GAS(tboot->acpi_sinfo.pm1a_evt_blk, fadt->xpm1a_event_block);
 261         TB_COPY_GAS(tboot->acpi_sinfo.pm1b_evt_blk, fadt->xpm1b_event_block);
 262
 263         /*
 264          * We need phys addr of waking vector, but can't use virt_to_phys() on
 265          * &acpi_gbl_FACS because it is ioremap'ed, so calc from FACS phys
 266          * addr.
 267          */
 268         tboot->acpi_sinfo.wakeup_vector = fadt->facs +
 269                 offsetof(struct acpi_table_facs, firmware_waking_vector);
 270 }
 271
 272 static int tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control)
 273 {
 274         static u32 acpi_shutdown_map[ACPI_S_STATE_COUNT] = {
 275                 /* S0,1,2: */ -1, -1, -1,
 276                 /* S3: */ TB_SHUTDOWN_S3,
 277                 /* S4: */ TB_SHUTDOWN_S4,
 278                 /* S5: */ TB_SHUTDOWN_S5 };
 279
 280         if (!tboot_enabled())
 281                 return 0;
 282
 283         tboot_copy_fadt(&acpi_gbl_FADT);
 284         tboot->acpi_sinfo.pm1a_cnt_val = pm1a_control;
 285         tboot->acpi_sinfo.pm1b_cnt_val = pm1b_control;
 286         /* we always use the 32b wakeup vector */
 287         tboot->acpi_sinfo.vector_width = 32;
 288
 289         if (sleep_state >= ACPI_S_STATE_COUNT ||
 290             acpi_shutdown_map[sleep_state] == -1) {
 291                 pr_warn("unsupported sleep state 0x%x\n", sleep_state);
 292                 return -1;
 293         }
 294
 295         tboot_shutdown(acpi_shutdown_map[sleep_state]);
 296         return 0;
 297 }
 298
 299 static int tboot_extended_sleep(u8 sleep_state, u32 val_a, u32 val_b)
 300 {
 301         if (!tboot_enabled())
 302                 return 0;
 303
 304         pr_warn("tboot is not able to suspend on platforms with reduced hardware sleep (ACPIv5)");
 305         return -ENODEV;
 306 }
 307
 308 static atomic_t ap_wfs_count;
 309
 310 static int tboot_wait_for_aps(int num_aps)
 311 {
 312         unsigned long timeout;
 313
 314         timeout = AP_WAIT_TIMEOUT*HZ;
 315         while (atomic_read((atomic_t *)&tboot->num_in_wfs) != num_aps &&
 316                timeout) {
 317                 mdelay(1);
 318                 timeout--;
 319         }
 320
 321         if (timeout)
 322                 pr_warn("tboot wait for APs timeout\n");
 323
 324         return !(atomic_read((atomic_t *)&tboot->num_in_wfs) == num_aps);
 325 }
 326
 327 static int tboot_dying_cpu(unsigned int cpu)
 328 {
 329         atomic_inc(&ap_wfs_count);
 330         if (num_online_cpus() == 1) {
 331                 if (tboot_wait_for_aps(atomic_read(&ap_wfs_count)))
 332                         return -EBUSY;
 333         }
 334         return 0;
 335 }
 336
 337 #ifdef CONFIG_DEBUG_FS
 338
 339 #define TBOOT_LOG_UUID  { 0x26, 0x25, 0x19, 0xc0, 0x30, 0x6b, 0xb4, 0x4d, \
 340                           0x4c, 0x84, 0xa3, 0xe9, 0x53, 0xb8, 0x81, 0x74 }
 341
 342 #define TBOOT_SERIAL_LOG_ADDR   0x60000
 343 #define TBOOT_SERIAL_LOG_SIZE   0x08000
 344 #define LOG_MAX_SIZE_OFF        16
 345 #define LOG_BUF_OFF             24
 346
 347 static uint8_t tboot_log_uuid[16] = TBOOT_LOG_UUID;
 348
 349 static ssize_t tboot_log_read(struct file *file, char __user *user_buf, size_t count, loff_t *ppos)
 350 {
 351         void __iomem *log_base;
 352         u8 log_uuid[16];
 353         u32 max_size;
 354         void *kbuf;
 355         int ret = -EFAULT;
 356
 357         log_base = ioremap_nocache(TBOOT_SERIAL_LOG_ADDR, TBOOT_SERIAL_LOG_SIZE);
 358         if (!log_base)
 359                 return ret;
 360
 361         memcpy_fromio(log_uuid, log_base, sizeof(log_uuid));
 362         if (memcmp(&tboot_log_uuid, log_uuid, sizeof(log_uuid)))
 363                 goto err_iounmap;
 364
 365         max_size = readl(log_base + LOG_MAX_SIZE_OFF);
 366         if (*ppos >= max_size) {
 367                 ret = 0;
 368                 goto err_iounmap;
 369         }
 370
 371         if (*ppos + count > max_size)
 372                 count = max_size - *ppos;
 373
 374         kbuf = kmalloc(count, GFP_KERNEL);
 375         if (!kbuf) {
 376                 ret = -ENOMEM;
 377                 goto err_iounmap;
 378         }
 379
 380         memcpy_fromio(kbuf, log_base + LOG_BUF_OFF + *ppos, count);
 381         if (copy_to_user(user_buf, kbuf, count))
 382                 goto err_kfree;
 383
 384         *ppos += count;
 385
 386         ret = count;
 387
 388 err_kfree:
 389         kfree(kbuf);
 390
 391 err_iounmap:
 392         iounmap(log_base);
 393
 394         return ret;
 395 }
 396
 397 static const struct file_operations tboot_log_fops = {
 398         .read   = tboot_log_read,
 399         .llseek = default_llseek,
 400 };
 401
 402 #endif /* CONFIG_DEBUG_FS */
 403
 404 static __init int tboot_late_init(void)
 405 {
 406         if (!tboot_enabled())
 407                 return 0;
 408
 409         tboot_create_trampoline();
 410
 411         atomic_set(&ap_wfs_count, 0);
 412         cpuhp_setup_state(CPUHP_AP_X86_TBOOT_DYING, "x86/tboot:dying", NULL,
 413                           tboot_dying_cpu);
 414 #ifdef CONFIG_DEBUG_FS
 415         debugfs_create_file("tboot_log", S_IRUSR,
 416                         arch_debugfs_dir, NULL, &tboot_log_fops);
 417 #endif
 418
 419         acpi_os_set_prepare_sleep(&tboot_sleep);
 420         acpi_os_set_prepare_extended_sleep(&tboot_extended_sleep);
 421         return 0;
 422 }
 423
 424 late_initcall(tboot_late_init);
 425
 426 /*
 427  * TXT configuration registers (offsets from TXT_{PUB, PRIV}_CONFIG_REGS_BASE)
 428  */
 429
 430 #define TXT_PUB_CONFIG_REGS_BASE       0xfed30000
 431 #define TXT_PRIV_CONFIG_REGS_BASE      0xfed20000
 432
 433 /* # pages for each config regs space - used by fixmap */
 434 #define NR_TXT_CONFIG_PAGES     ((TXT_PUB_CONFIG_REGS_BASE -                \
 435                                   TXT_PRIV_CONFIG_REGS_BASE) >> PAGE_SHIFT)
 436
 437 /* offsets from pub/priv config space */
 438 #define TXTCR_HEAP_BASE             0x0300
 439 #define TXTCR_HEAP_SIZE             0x0308
 440
 441 #define SHA1_SIZE      20
 442
 443 struct sha1_hash {
 444         u8 hash[SHA1_SIZE];
 445 };
 446
 447 struct sinit_mle_data {
 448         u32               version;             /* currently 6 */
 449         struct sha1_hash  bios_acm_id;
 450         u32               edx_senter_flags;
 451         u64               mseg_valid;
 452         struct sha1_hash  sinit_hash;
 453         struct sha1_hash  mle_hash;
 454         struct sha1_hash  stm_hash;
 455         struct sha1_hash  lcp_policy_hash;
 456         u32               lcp_policy_control;
 457         u32               rlp_wakeup_addr;
 458         u32               reserved;
 459         u32               num_mdrs;
 460         u32               mdrs_off;
 461         u32               num_vtd_dmars;
 462         u32               vtd_dmars_off;
 463 } __packed;
 464
 465 struct acpi_table_header *tboot_get_dmar_table(struct acpi_table_header *dmar_tbl)
 466 {
 467         void *heap_base, *heap_ptr, *config;
 468
 469         if (!tboot_enabled())
 470                 return dmar_tbl;
 471
 472         /*
 473          * ACPI tables may not be DMA protected by tboot, so use DMAR copy
 474          * SINIT saved in SinitMleData in TXT heap (which is DMA protected)
 475          */
 476
 477         /* map config space in order to get heap addr */
 478         config = ioremap(TXT_PUB_CONFIG_REGS_BASE, NR_TXT_CONFIG_PAGES *
 479                          PAGE_SIZE);
 480         if (!config)
 481                 return NULL;
 482
 483         /* now map TXT heap */
 484         heap_base = ioremap(*(u64 *)(config + TXTCR_HEAP_BASE),
 485                             *(u64 *)(config + TXTCR_HEAP_SIZE));
 486         iounmap(config);
 487         if (!heap_base)
 488                 return NULL;
 489
 490         /* walk heap to SinitMleData */
 491         /* skip BiosData */
 492         heap_ptr = heap_base + *(u64 *)heap_base;
 493         /* skip OsMleData */
 494         heap_ptr += *(u64 *)heap_ptr;
 495         /* skip OsSinitData */
 496         heap_ptr += *(u64 *)heap_ptr;
 497         /* now points to SinitMleDataSize; set to SinitMleData */
 498         heap_ptr += sizeof(u64);
 499         /* get addr of DMAR table */
 500         dmar_tbl = (struct acpi_table_header *)(heap_ptr +
 501                    ((struct sinit_mle_data *)heap_ptr)->vtd_dmars_off -
 502                    sizeof(u64));
 503
 504         /* don't unmap heap because dmar.c needs access to this */
 505
 506         return dmar_tbl;
 507 }
 508
 509 int tboot_force_iommu(void)
 510 {
 511         if (!tboot_enabled())
 512                 return 0;
 513
 514         if (intel_iommu_tboot_noforce)
 515                 return 1;
 516
 517         if (no_iommu || swiotlb || dmar_disabled)
 518                 pr_warn("Forcing Intel-IOMMU to enabled\n");
 519
 520         dmar_disabled = 0;
 521 #ifdef CONFIG_SWIOTLB
 522         swiotlb = 0;
 523 #endif
 524         no_iommu = 0;
 525
 526         return 1;
 527 }