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/pgalloc.h>
  27 #include <asm/swiotlb.h>
  28 #include <asm/fixmap.h>
  29 #include <asm/proto.h>
  30 #include <asm/setup.h>
  31 #include <asm/e820/api.h>
  32 #include <asm/io.h>
  33
  34 #include "../realmode/rm/wakeup.h"
  35
  36 /* Global pointer to shared data; NULL means no measured launch. */
  37 static struct tboot *tboot __read_mostly;
  38
  39 /* timeout for APs (in secs) to enter wait-for-SIPI state during shutdown */
  40 #define AP_WAIT_TIMEOUT         1
  41
  42 #undef pr_fmt
  43 #define pr_fmt(fmt)     "tboot: " fmt
  44
  45 static u8 tboot_uuid[16] __initdata = TBOOT_UUID;
  46
  47 bool tboot_enabled(void)
  48 {
  49         return tboot != NULL;
  50 }
  51
  52 /* noinline to prevent gcc from warning about dereferencing constant fixaddr */
  53 static noinline __init bool check_tboot_version(void)
  54 {
  55         if (memcmp(&tboot_uuid, &tboot->uuid, sizeof(tboot->uuid))) {
  56                 pr_warn("tboot at 0x%llx is invalid\n", boot_params.tboot_addr);
  57                 return false;
  58         }
  59
  60         if (tboot->version < 5) {
  61                 pr_warn("tboot version is invalid: %u\n", tboot->version);
  62                 return false;
  63         }
  64
  65         pr_info("found shared page at phys addr 0x%llx:\n",
  66                 boot_params.tboot_addr);
  67         pr_debug("version: %d\n", tboot->version);
  68         pr_debug("log_addr: 0x%08x\n", tboot->log_addr);
  69         pr_debug("shutdown_entry: 0x%x\n", tboot->shutdown_entry);
  70         pr_debug("tboot_base: 0x%08x\n", tboot->tboot_base);
  71         pr_debug("tboot_size: 0x%x\n", tboot->tboot_size);
  72
  73         return true;
  74 }
  75
  76 void __init tboot_probe(void)
  77 {
  78         /* Look for valid page-aligned address for shared page. */
  79         if (!boot_params.tboot_addr)
  80                 return;
  81         /*
  82          * also verify that it is mapped as we expect it before calling
  83          * set_fixmap(), to reduce chance of garbage value causing crash
  84          */
  85         if (!e820__mapped_any(boot_params.tboot_addr,
  86                              boot_params.tboot_addr, E820_TYPE_RESERVED)) {
  87                 pr_warn("non-0 tboot_addr but it is not of type E820_TYPE_RESERVED\n");
  88                 return;
  89         }
  90
  91         /* Map and check for tboot UUID. */
  92         set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
  93         tboot = (void *)fix_to_virt(FIX_TBOOT_BASE);
  94         if (!check_tboot_version())
  95                 tboot = NULL;
  96 }
  97
  98 static pgd_t *tboot_pg_dir;
  99 static struct mm_struct tboot_mm = {
 100         .mm_rb          = RB_ROOT,
 101         .pgd            = swapper_pg_dir,
 102         .mm_users       = ATOMIC_INIT(2),
 103         .mm_count       = ATOMIC_INIT(1),
 104         .write_protect_seq = SEQCNT_ZERO(tboot_mm.write_protect_seq),
 105         MMAP_LOCK_INITIALIZER(init_mm)
 106         .page_table_lock =  __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
 107         .mmlist         = LIST_HEAD_INIT(init_mm.mmlist),
 108 };
 109
 110 static inline void switch_to_tboot_pt(void)
 111 {
 112         write_cr3(virt_to_phys(tboot_pg_dir));
 113 }
 114
 115 static int map_tboot_page(unsigned long vaddr, unsigned long pfn,
 116                           pgprot_t prot)
 117 {
 118         pgd_t *pgd;
 119         p4d_t *p4d;
 120         pud_t *pud;
 121         pmd_t *pmd;
 122         pte_t *pte;
 123
 124         pgd = pgd_offset(&tboot_mm, vaddr);
 125         p4d = p4d_alloc(&tboot_mm, pgd, vaddr);
 126         if (!p4d)
 127                 return -1;
 128         pud = pud_alloc(&tboot_mm, p4d, vaddr);
 129         if (!pud)
 130                 return -1;
 131         pmd = pmd_alloc(&tboot_mm, pud, vaddr);
 132         if (!pmd)
 133                 return -1;
 134         pte = pte_alloc_map(&tboot_mm, pmd, vaddr);
 135         if (!pte)
 136                 return -1;
 137         set_pte_at(&tboot_mm, vaddr, pte, pfn_pte(pfn, prot));
 138         pte_unmap(pte);
 139
 140         /*
 141          * PTI poisons low addresses in the kernel page tables in the
 142          * name of making them unusable for userspace.  To execute
 143          * code at such a low address, the poison must be cleared.
 144          *
 145          * Note: 'pgd' actually gets set in p4d_alloc() _or_
 146          * pud_alloc() depending on 4/5-level paging.
 147          */
 148         pgd->pgd &= ~_PAGE_NX;
 149
 150         return 0;
 151 }
 152
 153 static int map_tboot_pages(unsigned long vaddr, unsigned long start_pfn,
 154                            unsigned long nr)
 155 {
 156         /* Reuse the original kernel mapping */
 157         tboot_pg_dir = pgd_alloc(&tboot_mm);
 158         if (!tboot_pg_dir)
 159                 return -1;
 160
 161         for (; nr > 0; nr--, vaddr += PAGE_SIZE, start_pfn++) {
 162                 if (map_tboot_page(vaddr, start_pfn, PAGE_KERNEL_EXEC))
 163                         return -1;
 164         }
 165
 166         return 0;
 167 }
 168
 169 static void tboot_create_trampoline(void)
 170 {
 171         u32 map_base, map_size;
 172
 173         /* Create identity map for tboot shutdown code. */
 174         map_base = PFN_DOWN(tboot->tboot_base);
 175         map_size = PFN_UP(tboot->tboot_size);
 176         if (map_tboot_pages(map_base << PAGE_SHIFT, map_base, map_size))
 177                 panic("tboot: Error mapping tboot pages (mfns) @ 0x%x, 0x%x\n",
 178                       map_base, map_size);
 179 }
 180
 181 #ifdef CONFIG_ACPI_SLEEP
 182
 183 static void add_mac_region(phys_addr_t start, unsigned long size)
 184 {
 185         struct tboot_mac_region *mr;
 186         phys_addr_t end = start + size;
 187
 188         if (tboot->num_mac_regions >= MAX_TB_MAC_REGIONS)
 189                 panic("tboot: Too many MAC regions\n");
 190
 191         if (start && size) {
 192                 mr = &tboot->mac_regions[tboot->num_mac_regions++];
 193                 mr->start = round_down(start, PAGE_SIZE);
 194                 mr->size  = round_up(end, PAGE_SIZE) - mr->start;
 195         }
 196 }
 197
 198 static int tboot_setup_sleep(void)
 199 {
 200         int i;
 201
 202         tboot->num_mac_regions = 0;
 203
 204         for (i = 0; i < e820_table->nr_entries; i++) {
 205                 if ((e820_table->entries[i].type != E820_TYPE_RAM)
 206                  && (e820_table->entries[i].type != E820_TYPE_RESERVED_KERN))
 207                         continue;
 208
 209                 add_mac_region(e820_table->entries[i].addr, e820_table->entries[i].size);
 210         }
 211
 212         tboot->acpi_sinfo.kernel_s3_resume_vector =
 213                 real_mode_header->wakeup_start;
 214
 215         return 0;
 216 }
 217
 218 #else /* no CONFIG_ACPI_SLEEP */
 219
 220 static int tboot_setup_sleep(void)
 221 {
 222         /* S3 shutdown requested, but S3 not supported by the kernel... */
 223         BUG();
 224         return -1;
 225 }
 226
 227 #endif
 228
 229 void tboot_shutdown(u32 shutdown_type)
 230 {
 231         void (*shutdown)(void);
 232
 233         if (!tboot_enabled())
 234                 return;
 235
 236         /*
 237          * if we're being called before the 1:1 mapping is set up then just
 238          * return and let the normal shutdown happen; this should only be
 239          * due to very early panic()
 240          */
 241         if (!tboot_pg_dir)
 242                 return;
 243
 244         /* if this is S3 then set regions to MAC */
 245         if (shutdown_type == TB_SHUTDOWN_S3)
 246                 if (tboot_setup_sleep())
 247                         return;
 248
 249         tboot->shutdown_type = shutdown_type;
 250
 251         switch_to_tboot_pt();
 252
 253         shutdown = (void(*)(void))(unsigned long)tboot->shutdown_entry;
 254         shutdown();
 255
 256         /* should not reach here */
 257         while (1)
 258                 halt();
 259 }
 260
 261 static void tboot_copy_fadt(const struct acpi_table_fadt *fadt)
 262 {
 263 #define TB_COPY_GAS(tbg, g)                     \
 264         tbg.space_id     = g.space_id;          \
 265         tbg.bit_width    = g.bit_width;         \
 266         tbg.bit_offset   = g.bit_offset;        \
 267         tbg.access_width = g.access_width;      \
 268         tbg.address      = g.address;
 269
 270         TB_COPY_GAS(tboot->acpi_sinfo.pm1a_cnt_blk, fadt->xpm1a_control_block);
 271         TB_COPY_GAS(tboot->acpi_sinfo.pm1b_cnt_blk, fadt->xpm1b_control_block);
 272         TB_COPY_GAS(tboot->acpi_sinfo.pm1a_evt_blk, fadt->xpm1a_event_block);
 273         TB_COPY_GAS(tboot->acpi_sinfo.pm1b_evt_blk, fadt->xpm1b_event_block);
 274
 275         /*
 276          * We need phys addr of waking vector, but can't use virt_to_phys() on
 277          * &acpi_gbl_FACS because it is ioremap'ed, so calc from FACS phys
 278          * addr.
 279          */
 280         tboot->acpi_sinfo.wakeup_vector = fadt->facs +
 281                 offsetof(struct acpi_table_facs, firmware_waking_vector);
 282 }
 283
 284 static int tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control)
 285 {
 286         static u32 acpi_shutdown_map[ACPI_S_STATE_COUNT] = {
 287                 /* S0,1,2: */ -1, -1, -1,
 288                 /* S3: */ TB_SHUTDOWN_S3,
 289                 /* S4: */ TB_SHUTDOWN_S4,
 290                 /* S5: */ TB_SHUTDOWN_S5 };
 291
 292         if (!tboot_enabled())
 293                 return 0;
 294
 295         tboot_copy_fadt(&acpi_gbl_FADT);
 296         tboot->acpi_sinfo.pm1a_cnt_val = pm1a_control;
 297         tboot->acpi_sinfo.pm1b_cnt_val = pm1b_control;
 298         /* we always use the 32b wakeup vector */
 299         tboot->acpi_sinfo.vector_width = 32;
 300
 301         if (sleep_state >= ACPI_S_STATE_COUNT ||
 302             acpi_shutdown_map[sleep_state] == -1) {
 303                 pr_warn("unsupported sleep state 0x%x\n", sleep_state);
 304                 return -1;
 305         }
 306
 307         tboot_shutdown(acpi_shutdown_map[sleep_state]);
 308         return 0;
 309 }
 310
 311 static int tboot_extended_sleep(u8 sleep_state, u32 val_a, u32 val_b)
 312 {
 313         if (!tboot_enabled())
 314                 return 0;
 315
 316         pr_warn("tboot is not able to suspend on platforms with reduced hardware sleep (ACPIv5)");
 317         return -ENODEV;
 318 }
 319
 320 static atomic_t ap_wfs_count;
 321
 322 static int tboot_wait_for_aps(int num_aps)
 323 {
 324         unsigned long timeout;
 325
 326         timeout = AP_WAIT_TIMEOUT*HZ;
 327         while (atomic_read((atomic_t *)&tboot->num_in_wfs) != num_aps &&
 328                timeout) {
 329                 mdelay(1);
 330                 timeout--;
 331         }
 332
 333         if (timeout)
 334                 pr_warn("tboot wait for APs timeout\n");
 335
 336         return !(atomic_read((atomic_t *)&tboot->num_in_wfs) == num_aps);
 337 }
 338
 339 static int tboot_dying_cpu(unsigned int cpu)
 340 {
 341         atomic_inc(&ap_wfs_count);
 342         if (num_online_cpus() == 1) {
 343                 if (tboot_wait_for_aps(atomic_read(&ap_wfs_count)))
 344                         return -EBUSY;
 345         }
 346         return 0;
 347 }
 348
 349 #ifdef CONFIG_DEBUG_FS
 350
 351 #define TBOOT_LOG_UUID  { 0x26, 0x25, 0x19, 0xc0, 0x30, 0x6b, 0xb4, 0x4d, \
 352                           0x4c, 0x84, 0xa3, 0xe9, 0x53, 0xb8, 0x81, 0x74 }
 353
 354 #define TBOOT_SERIAL_LOG_ADDR   0x60000
 355 #define TBOOT_SERIAL_LOG_SIZE   0x08000
 356 #define LOG_MAX_SIZE_OFF        16
 357 #define LOG_BUF_OFF             24
 358
 359 static uint8_t tboot_log_uuid[16] = TBOOT_LOG_UUID;
 360
 361 static ssize_t tboot_log_read(struct file *file, char __user *user_buf, size_t count, loff_t *ppos)
 362 {
 363         void __iomem *log_base;
 364         u8 log_uuid[16];
 365         u32 max_size;
 366         void *kbuf;
 367         int ret = -EFAULT;
 368
 369         log_base = ioremap(TBOOT_SERIAL_LOG_ADDR, TBOOT_SERIAL_LOG_SIZE);
 370         if (!log_base)
 371                 return ret;
 372
 373         memcpy_fromio(log_uuid, log_base, sizeof(log_uuid));
 374         if (memcmp(&tboot_log_uuid, log_uuid, sizeof(log_uuid)))
 375                 goto err_iounmap;
 376
 377         max_size = readl(log_base + LOG_MAX_SIZE_OFF);
 378         if (*ppos >= max_size) {
 379                 ret = 0;
 380                 goto err_iounmap;
 381         }
 382
 383         if (*ppos + count > max_size)
 384                 count = max_size - *ppos;
 385
 386         kbuf = kmalloc(count, GFP_KERNEL);
 387         if (!kbuf) {
 388                 ret = -ENOMEM;
 389                 goto err_iounmap;
 390         }
 391
 392         memcpy_fromio(kbuf, log_base + LOG_BUF_OFF + *ppos, count);
 393         if (copy_to_user(user_buf, kbuf, count))
 394                 goto err_kfree;
 395
 396         *ppos += count;
 397
 398         ret = count;
 399
 400 err_kfree:
 401         kfree(kbuf);
 402
 403 err_iounmap:
 404         iounmap(log_base);
 405
 406         return ret;
 407 }
 408
 409 static const struct file_operations tboot_log_fops = {
 410         .read   = tboot_log_read,
 411         .llseek = default_llseek,
 412 };
 413
 414 #endif /* CONFIG_DEBUG_FS */
 415
 416 static __init int tboot_late_init(void)
 417 {
 418         if (!tboot_enabled())
 419                 return 0;
 420
 421         tboot_create_trampoline();
 422
 423         atomic_set(&ap_wfs_count, 0);
 424         cpuhp_setup_state(CPUHP_AP_X86_TBOOT_DYING, "x86/tboot:dying", NULL,
 425                           tboot_dying_cpu);
 426 #ifdef CONFIG_DEBUG_FS
 427         debugfs_create_file("tboot_log", S_IRUSR,
 428                         arch_debugfs_dir, NULL, &tboot_log_fops);
 429 #endif
 430
 431         acpi_os_set_prepare_sleep(&tboot_sleep);
 432         acpi_os_set_prepare_extended_sleep(&tboot_extended_sleep);
 433         return 0;
 434 }
 435
 436 late_initcall(tboot_late_init);
 437
 438 /*
 439  * TXT configuration registers (offsets from TXT_{PUB, PRIV}_CONFIG_REGS_BASE)
 440  */
 441
 442 #define TXT_PUB_CONFIG_REGS_BASE       0xfed30000
 443 #define TXT_PRIV_CONFIG_REGS_BASE      0xfed20000
 444
 445 /* # pages for each config regs space - used by fixmap */
 446 #define NR_TXT_CONFIG_PAGES     ((TXT_PUB_CONFIG_REGS_BASE -                \
 447                                   TXT_PRIV_CONFIG_REGS_BASE) >> PAGE_SHIFT)
 448
 449 /* offsets from pub/priv config space */
 450 #define TXTCR_HEAP_BASE             0x0300
 451 #define TXTCR_HEAP_SIZE             0x0308
 452
 453 #define SHA1_SIZE      20
 454
 455 struct sha1_hash {
 456         u8 hash[SHA1_SIZE];
 457 };
 458
 459 struct sinit_mle_data {
 460         u32               version;             /* currently 6 */
 461         struct sha1_hash  bios_acm_id;
 462         u32               edx_senter_flags;
 463         u64               mseg_valid;
 464         struct sha1_hash  sinit_hash;
 465         struct sha1_hash  mle_hash;
 466         struct sha1_hash  stm_hash;
 467         struct sha1_hash  lcp_policy_hash;
 468         u32               lcp_policy_control;
 469         u32               rlp_wakeup_addr;
 470         u32               reserved;
 471         u32               num_mdrs;
 472         u32               mdrs_off;
 473         u32               num_vtd_dmars;
 474         u32               vtd_dmars_off;
 475 } __packed;
 476
 477 struct acpi_table_header *tboot_get_dmar_table(struct acpi_table_header *dmar_tbl)
 478 {
 479         void *heap_base, *heap_ptr, *config;
 480
 481         if (!tboot_enabled())
 482                 return dmar_tbl;
 483
 484         /*
 485          * ACPI tables may not be DMA protected by tboot, so use DMAR copy
 486          * SINIT saved in SinitMleData in TXT heap (which is DMA protected)
 487          */
 488
 489         /* map config space in order to get heap addr */
 490         config = ioremap(TXT_PUB_CONFIG_REGS_BASE, NR_TXT_CONFIG_PAGES *
 491                          PAGE_SIZE);
 492         if (!config)
 493                 return NULL;
 494
 495         /* now map TXT heap */
 496         heap_base = ioremap(*(u64 *)(config + TXTCR_HEAP_BASE),
 497                             *(u64 *)(config + TXTCR_HEAP_SIZE));
 498         iounmap(config);
 499         if (!heap_base)
 500                 return NULL;
 501
 502         /* walk heap to SinitMleData */
 503         /* skip BiosData */
 504         heap_ptr = heap_base + *(u64 *)heap_base;
 505         /* skip OsMleData */
 506         heap_ptr += *(u64 *)heap_ptr;
 507         /* skip OsSinitData */
 508         heap_ptr += *(u64 *)heap_ptr;
 509         /* now points to SinitMleDataSize; set to SinitMleData */
 510         heap_ptr += sizeof(u64);
 511         /* get addr of DMAR table */
 512         dmar_tbl = (struct acpi_table_header *)(heap_ptr +
 513                    ((struct sinit_mle_data *)heap_ptr)->vtd_dmars_off -
 514                    sizeof(u64));
 515
 516         /* don't unmap heap because dmar.c needs access to this */
 517
 518         return dmar_tbl;
 519 }
 520
 521 int tboot_force_iommu(void)
 522 {
 523         if (!tboot_enabled())
 524                 return 0;
 525
 526         if (no_iommu || dmar_disabled)
 527                 pr_warn("Forcing Intel-IOMMU to enabled\n");
 528
 529         dmar_disabled = 0;
 530         no_iommu = 0;
 531
 532         return 1;
 533 }