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/init_task.h>
  10 #include <linux/spinlock.h>
  11 #include <linux/export.h>
  12 #include <linux/delay.h>
  13 #include <linux/sched.h>
  14 #include <linux/init.h>
  15 #include <linux/dmar.h>
  16 #include <linux/cpu.h>
  17 #include <linux/pfn.h>
  18 #include <linux/mm.h>
  19 #include <linux/tboot.h>
  20 #include <linux/debugfs.h>
  21
  22 #include <asm/realmode.h>
  23 #include <asm/processor.h>
  24 #include <asm/bootparam.h>
  25 #include <asm/pgalloc.h>
  26 #include <asm/fixmap.h>
  27 #include <asm/proto.h>
  28 #include <asm/setup.h>
  29 #include <asm/e820/api.h>
  30 #include <asm/io.h>
  31
  32 #include "../realmode/rm/wakeup.h"
  33
  34 /* Global pointer to shared data; NULL means no measured launch. */
  35 static struct tboot *tboot __read_mostly;
  36
  37 /* timeout for APs (in secs) to enter wait-for-SIPI state during shutdown */
  38 #define AP_WAIT_TIMEOUT         1
  39
  40 #undef pr_fmt
  41 #define pr_fmt(fmt)     "tboot: " fmt
  42
  43 static u8 tboot_uuid[16] __initdata = TBOOT_UUID;
  44
  45 bool tboot_enabled(void)
  46 {
  47         return tboot != NULL;
  48 }
  49
  50 /* noinline to prevent gcc from warning about dereferencing constant fixaddr */
  51 static noinline __init bool check_tboot_version(void)
  52 {
  53         if (memcmp(&tboot_uuid, &tboot->uuid, sizeof(tboot->uuid))) {
  54                 pr_warn("tboot at 0x%llx is invalid\n", boot_params.tboot_addr);
  55                 return false;
  56         }
  57
  58         if (tboot->version < 5) {
  59                 pr_warn("tboot version is invalid: %u\n", tboot->version);
  60                 return false;
  61         }
  62
  63         pr_info("found shared page at phys addr 0x%llx:\n",
  64                 boot_params.tboot_addr);
  65         pr_debug("version: %d\n", tboot->version);
  66         pr_debug("log_addr: 0x%08x\n", tboot->log_addr);
  67         pr_debug("shutdown_entry: 0x%x\n", tboot->shutdown_entry);
  68         pr_debug("tboot_base: 0x%08x\n", tboot->tboot_base);
  69         pr_debug("tboot_size: 0x%x\n", tboot->tboot_size);
  70
  71         return true;
  72 }
  73
  74 void __init tboot_probe(void)
  75 {
  76         /* Look for valid page-aligned address for shared page. */
  77         if (!boot_params.tboot_addr)
  78                 return;
  79         /*
  80          * also verify that it is mapped as we expect it before calling
  81          * set_fixmap(), to reduce chance of garbage value causing crash
  82          */
  83         if (!e820__mapped_any(boot_params.tboot_addr,
  84                              boot_params.tboot_addr, E820_TYPE_RESERVED)) {
  85                 pr_warn("non-0 tboot_addr but it is not of type E820_TYPE_RESERVED\n");
  86                 return;
  87         }
  88
  89         /* Map and check for tboot UUID. */
  90         set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
  91         tboot = (void *)fix_to_virt(FIX_TBOOT_BASE);
  92         if (!check_tboot_version())
  93                 tboot = NULL;
  94 }
  95
  96 static pgd_t *tboot_pg_dir;
  97 static struct mm_struct tboot_mm = {
  98         .mm_mt          = MTREE_INIT_EXT(mm_mt, MM_MT_FLAGS, tboot_mm.mmap_lock),
  99         .pgd            = swapper_pg_dir,
 100         .mm_users       = ATOMIC_INIT(2),
 101         .mm_count       = ATOMIC_INIT(1),
 102         .write_protect_seq = SEQCNT_ZERO(tboot_mm.write_protect_seq),
 103         MMAP_LOCK_INITIALIZER(init_mm)
 104         .page_table_lock =  __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
 105         .mmlist         = LIST_HEAD_INIT(init_mm.mmlist),
 106 };
 107
 108 static inline void switch_to_tboot_pt(void)
 109 {
 110         write_cr3(virt_to_phys(tboot_pg_dir));
 111 }
 112
 113 static int map_tboot_page(unsigned long vaddr, unsigned long pfn,
 114                           pgprot_t prot)
 115 {
 116         pgd_t *pgd;
 117         p4d_t *p4d;
 118         pud_t *pud;
 119         pmd_t *pmd;
 120         pte_t *pte;
 121
 122         pgd = pgd_offset(&tboot_mm, vaddr);
 123         p4d = p4d_alloc(&tboot_mm, pgd, vaddr);
 124         if (!p4d)
 125                 return -1;
 126         pud = pud_alloc(&tboot_mm, p4d, vaddr);
 127         if (!pud)
 128                 return -1;
 129         pmd = pmd_alloc(&tboot_mm, pud, vaddr);
 130         if (!pmd)
 131                 return -1;
 132         pte = pte_alloc_map(&tboot_mm, pmd, vaddr);
 133         if (!pte)
 134                 return -1;
 135         set_pte_at(&tboot_mm, vaddr, pte, pfn_pte(pfn, prot));
 136         pte_unmap(pte);
 137
 138         /*
 139          * PTI poisons low addresses in the kernel page tables in the
 140          * name of making them unusable for userspace.  To execute
 141          * code at such a low address, the poison must be cleared.
 142          *
 143          * Note: 'pgd' actually gets set in p4d_alloc() _or_
 144          * pud_alloc() depending on 4/5-level paging.
 145          */
 146         pgd->pgd &= ~_PAGE_NX;
 147
 148         return 0;
 149 }
 150
 151 static int map_tboot_pages(unsigned long vaddr, unsigned long start_pfn,
 152                            unsigned long nr)
 153 {
 154         /* Reuse the original kernel mapping */
 155         tboot_pg_dir = pgd_alloc(&tboot_mm);
 156         if (!tboot_pg_dir)
 157                 return -1;
 158
 159         for (; nr > 0; nr--, vaddr += PAGE_SIZE, start_pfn++) {
 160                 if (map_tboot_page(vaddr, start_pfn, PAGE_KERNEL_EXEC))
 161                         return -1;
 162         }
 163
 164         return 0;
 165 }
 166
 167 static void tboot_create_trampoline(void)
 168 {
 169         u32 map_base, map_size;
 170
 171         /* Create identity map for tboot shutdown code. */
 172         map_base = PFN_DOWN(tboot->tboot_base);
 173         map_size = PFN_UP(tboot->tboot_size);
 174         if (map_tboot_pages(map_base << PAGE_SHIFT, map_base, map_size))
 175                 panic("tboot: Error mapping tboot pages (mfns) @ 0x%x, 0x%x\n",
 176                       map_base, map_size);
 177 }
 178
 179 #ifdef CONFIG_ACPI_SLEEP
 180
 181 static void add_mac_region(phys_addr_t start, unsigned long size)
 182 {
 183         struct tboot_mac_region *mr;
 184         phys_addr_t end = start + size;
 185
 186         if (tboot->num_mac_regions >= MAX_TB_MAC_REGIONS)
 187                 panic("tboot: Too many MAC regions\n");
 188
 189         if (start && size) {
 190                 mr = &tboot->mac_regions[tboot->num_mac_regions++];
 191                 mr->start = round_down(start, PAGE_SIZE);
 192                 mr->size  = round_up(end, PAGE_SIZE) - mr->start;
 193         }
 194 }
 195
 196 static int tboot_setup_sleep(void)
 197 {
 198         int i;
 199
 200         tboot->num_mac_regions = 0;
 201
 202         for (i = 0; i < e820_table->nr_entries; i++) {
 203                 if ((e820_table->entries[i].type != E820_TYPE_RAM)
 204                  && (e820_table->entries[i].type != E820_TYPE_RESERVED_KERN))
 205                         continue;
 206
 207                 add_mac_region(e820_table->entries[i].addr, e820_table->entries[i].size);
 208         }
 209
 210         tboot->acpi_sinfo.kernel_s3_resume_vector =
 211                 real_mode_header->wakeup_start;
 212
 213         return 0;
 214 }
 215
 216 #else /* no CONFIG_ACPI_SLEEP */
 217
 218 static int tboot_setup_sleep(void)
 219 {
 220         /* S3 shutdown requested, but S3 not supported by the kernel... */
 221         BUG();
 222         return -1;
 223 }
 224
 225 #endif
 226
 227 void tboot_shutdown(u32 shutdown_type)
 228 {
 229         void (*shutdown)(void);
 230
 231         if (!tboot_enabled())
 232                 return;
 233
 234         /*
 235          * if we're being called before the 1:1 mapping is set up then just
 236          * return and let the normal shutdown happen; this should only be
 237          * due to very early panic()
 238          */
 239         if (!tboot_pg_dir)
 240                 return;
 241
 242         /* if this is S3 then set regions to MAC */
 243         if (shutdown_type == TB_SHUTDOWN_S3)
 244                 if (tboot_setup_sleep())
 245                         return;
 246
 247         tboot->shutdown_type = shutdown_type;
 248
 249         switch_to_tboot_pt();
 250
 251         shutdown = (void(*)(void))(unsigned long)tboot->shutdown_entry;
 252         shutdown();
 253
 254         /* should not reach here */
 255         while (1)
 256                 halt();
 257 }
 258
 259 static void tboot_copy_fadt(const struct acpi_table_fadt *fadt)
 260 {
 261 #define TB_COPY_GAS(tbg, g)                     \
 262         tbg.space_id     = g.space_id;          \
 263         tbg.bit_width    = g.bit_width;         \
 264         tbg.bit_offset   = g.bit_offset;        \
 265         tbg.access_width = g.access_width;      \
 266         tbg.address      = g.address;
 267
 268         TB_COPY_GAS(tboot->acpi_sinfo.pm1a_cnt_blk, fadt->xpm1a_control_block);
 269         TB_COPY_GAS(tboot->acpi_sinfo.pm1b_cnt_blk, fadt->xpm1b_control_block);
 270         TB_COPY_GAS(tboot->acpi_sinfo.pm1a_evt_blk, fadt->xpm1a_event_block);
 271         TB_COPY_GAS(tboot->acpi_sinfo.pm1b_evt_blk, fadt->xpm1b_event_block);
 272
 273         /*
 274          * We need phys addr of waking vector, but can't use virt_to_phys() on
 275          * &acpi_gbl_FACS because it is ioremap'ed, so calc from FACS phys
 276          * addr.
 277          */
 278         tboot->acpi_sinfo.wakeup_vector = fadt->facs +
 279                 offsetof(struct acpi_table_facs, firmware_waking_vector);
 280 }
 281
 282 static int tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control)
 283 {
 284         static u32 acpi_shutdown_map[ACPI_S_STATE_COUNT] = {
 285                 /* S0,1,2: */ -1, -1, -1,
 286                 /* S3: */ TB_SHUTDOWN_S3,
 287                 /* S4: */ TB_SHUTDOWN_S4,
 288                 /* S5: */ TB_SHUTDOWN_S5 };
 289
 290         if (!tboot_enabled())
 291                 return 0;
 292
 293         tboot_copy_fadt(&acpi_gbl_FADT);
 294         tboot->acpi_sinfo.pm1a_cnt_val = pm1a_control;
 295         tboot->acpi_sinfo.pm1b_cnt_val = pm1b_control;
 296         /* we always use the 32b wakeup vector */
 297         tboot->acpi_sinfo.vector_width = 32;
 298
 299         if (sleep_state >= ACPI_S_STATE_COUNT ||
 300             acpi_shutdown_map[sleep_state] == -1) {
 301                 pr_warn("unsupported sleep state 0x%x\n", sleep_state);
 302                 return -1;
 303         }
 304
 305         tboot_shutdown(acpi_shutdown_map[sleep_state]);
 306         return 0;
 307 }
 308
 309 static int tboot_extended_sleep(u8 sleep_state, u32 val_a, u32 val_b)
 310 {
 311         if (!tboot_enabled())
 312                 return 0;
 313
 314         pr_warn("tboot is not able to suspend on platforms with reduced hardware sleep (ACPIv5)");
 315         return -ENODEV;
 316 }
 317
 318 static atomic_t ap_wfs_count;
 319
 320 static int tboot_wait_for_aps(int num_aps)
 321 {
 322         unsigned long timeout;
 323
 324         timeout = AP_WAIT_TIMEOUT*HZ;
 325         while (atomic_read((atomic_t *)&tboot->num_in_wfs) != num_aps &&
 326                timeout) {
 327                 mdelay(1);
 328                 timeout--;
 329         }
 330
 331         if (timeout)
 332                 pr_warn("tboot wait for APs timeout\n");
 333
 334         return !(atomic_read((atomic_t *)&tboot->num_in_wfs) == num_aps);
 335 }
 336
 337 static int tboot_dying_cpu(unsigned int cpu)
 338 {
 339         atomic_inc(&ap_wfs_count);
 340         if (num_online_cpus() == 1) {
 341                 if (tboot_wait_for_aps(atomic_read(&ap_wfs_count)))
 342                         return -EBUSY;
 343         }
 344         return 0;
 345 }
 346
 347 #ifdef CONFIG_DEBUG_FS
 348
 349 #define TBOOT_LOG_UUID  { 0x26, 0x25, 0x19, 0xc0, 0x30, 0x6b, 0xb4, 0x4d, \
 350                           0x4c, 0x84, 0xa3, 0xe9, 0x53, 0xb8, 0x81, 0x74 }
 351
 352 #define TBOOT_SERIAL_LOG_ADDR   0x60000
 353 #define TBOOT_SERIAL_LOG_SIZE   0x08000
 354 #define LOG_MAX_SIZE_OFF        16
 355 #define LOG_BUF_OFF             24
 356
 357 static uint8_t tboot_log_uuid[16] = TBOOT_LOG_UUID;
 358
 359 static ssize_t tboot_log_read(struct file *file, char __user *user_buf, size_t count, loff_t *ppos)
 360 {
 361         void __iomem *log_base;
 362         u8 log_uuid[16];
 363         u32 max_size;
 364         void *kbuf;
 365         int ret = -EFAULT;
 366
 367         log_base = ioremap(TBOOT_SERIAL_LOG_ADDR, TBOOT_SERIAL_LOG_SIZE);
 368         if (!log_base)
 369                 return ret;
 370
 371         memcpy_fromio(log_uuid, log_base, sizeof(log_uuid));
 372         if (memcmp(&tboot_log_uuid, log_uuid, sizeof(log_uuid)))
 373                 goto err_iounmap;
 374
 375         max_size = readl(log_base + LOG_MAX_SIZE_OFF);
 376         if (*ppos >= max_size) {
 377                 ret = 0;
 378                 goto err_iounmap;
 379         }
 380
 381         if (*ppos + count > max_size)
 382                 count = max_size - *ppos;
 383
 384         kbuf = kmalloc(count, GFP_KERNEL);
 385         if (!kbuf) {
 386                 ret = -ENOMEM;
 387                 goto err_iounmap;
 388         }
 389
 390         memcpy_fromio(kbuf, log_base + LOG_BUF_OFF + *ppos, count);
 391         if (copy_to_user(user_buf, kbuf, count))
 392                 goto err_kfree;
 393
 394         *ppos += count;
 395
 396         ret = count;
 397
 398 err_kfree:
 399         kfree(kbuf);
 400
 401 err_iounmap:
 402         iounmap(log_base);
 403
 404         return ret;
 405 }
 406
 407 static const struct file_operations tboot_log_fops = {
 408         .read   = tboot_log_read,
 409         .llseek = default_llseek,
 410 };
 411
 412 #endif /* CONFIG_DEBUG_FS */
 413
 414 static __init int tboot_late_init(void)
 415 {
 416         if (!tboot_enabled())
 417                 return 0;
 418
 419         tboot_create_trampoline();
 420
 421         atomic_set(&ap_wfs_count, 0);
 422         cpuhp_setup_state(CPUHP_AP_X86_TBOOT_DYING, "x86/tboot:dying", NULL,
 423                           tboot_dying_cpu);
 424 #ifdef CONFIG_DEBUG_FS
 425         debugfs_create_file("tboot_log", S_IRUSR,
 426                         arch_debugfs_dir, NULL, &tboot_log_fops);
 427 #endif
 428
 429         acpi_os_set_prepare_sleep(&tboot_sleep);
 430         acpi_os_set_prepare_extended_sleep(&tboot_extended_sleep);
 431         return 0;
 432 }
 433
 434 late_initcall(tboot_late_init);
 435
 436 /*
 437  * TXT configuration registers (offsets from TXT_{PUB, PRIV}_CONFIG_REGS_BASE)
 438  */
 439
 440 #define TXT_PUB_CONFIG_REGS_BASE       0xfed30000
 441 #define TXT_PRIV_CONFIG_REGS_BASE      0xfed20000
 442
 443 /* # pages for each config regs space - used by fixmap */
 444 #define NR_TXT_CONFIG_PAGES     ((TXT_PUB_CONFIG_REGS_BASE -                \
 445                                   TXT_PRIV_CONFIG_REGS_BASE) >> PAGE_SHIFT)
 446
 447 /* offsets from pub/priv config space */
 448 #define TXTCR_HEAP_BASE             0x0300
 449 #define TXTCR_HEAP_SIZE             0x0308
 450
 451 #define SHA1_SIZE      20
 452
 453 struct sha1_hash {
 454         u8 hash[SHA1_SIZE];
 455 };
 456
 457 struct sinit_mle_data {
 458         u32               version;             /* currently 6 */
 459         struct sha1_hash  bios_acm_id;
 460         u32               edx_senter_flags;
 461         u64               mseg_valid;
 462         struct sha1_hash  sinit_hash;
 463         struct sha1_hash  mle_hash;
 464         struct sha1_hash  stm_hash;
 465         struct sha1_hash  lcp_policy_hash;
 466         u32               lcp_policy_control;
 467         u32               rlp_wakeup_addr;
 468         u32               reserved;
 469         u32               num_mdrs;
 470         u32               mdrs_off;
 471         u32               num_vtd_dmars;
 472         u32               vtd_dmars_off;
 473 } __packed;
 474
 475 struct acpi_table_header *tboot_get_dmar_table(struct acpi_table_header *dmar_tbl)
 476 {
 477         void *heap_base, *heap_ptr, *config;
 478
 479         if (!tboot_enabled())
 480                 return dmar_tbl;
 481
 482         /*
 483          * ACPI tables may not be DMA protected by tboot, so use DMAR copy
 484          * SINIT saved in SinitMleData in TXT heap (which is DMA protected)
 485          */
 486
 487         /* map config space in order to get heap addr */
 488         config = ioremap(TXT_PUB_CONFIG_REGS_BASE, NR_TXT_CONFIG_PAGES *
 489                          PAGE_SIZE);
 490         if (!config)
 491                 return NULL;
 492
 493         /* now map TXT heap */
 494         heap_base = ioremap(*(u64 *)(config + TXTCR_HEAP_BASE),
 495                             *(u64 *)(config + TXTCR_HEAP_SIZE));
 496         iounmap(config);
 497         if (!heap_base)
 498                 return NULL;
 499
 500         /* walk heap to SinitMleData */
 501         /* skip BiosData */
 502         heap_ptr = heap_base + *(u64 *)heap_base;
 503         /* skip OsMleData */
 504         heap_ptr += *(u64 *)heap_ptr;
 505         /* skip OsSinitData */
 506         heap_ptr += *(u64 *)heap_ptr;
 507         /* now points to SinitMleDataSize; set to SinitMleData */
 508         heap_ptr += sizeof(u64);
 509         /* get addr of DMAR table */
 510         dmar_tbl = (struct acpi_table_header *)(heap_ptr +
 511                    ((struct sinit_mle_data *)heap_ptr)->vtd_dmars_off -
 512                    sizeof(u64));
 513
 514         /* don't unmap heap because dmar.c needs access to this */
 515
 516         return dmar_tbl;
 517 }