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 void __init tboot_probe(void)
  53 {
  54         /* Look for valid page-aligned address for shared page. */
  55         if (!boot_params.tboot_addr)
  56                 return;
  57         /*
  58          * also verify that it is mapped as we expect it before calling
  59          * set_fixmap(), to reduce chance of garbage value causing crash
  60          */
  61         if (!e820__mapped_any(boot_params.tboot_addr,
  62                              boot_params.tboot_addr, E820_TYPE_RESERVED)) {
  63                 pr_warn("non-0 tboot_addr but it is not of type E820_TYPE_RESERVED\n");
  64                 return;
  65         }
  66
  67         /* Map and check for tboot UUID. */
  68         set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
  69         tboot = (struct tboot *)fix_to_virt(FIX_TBOOT_BASE);
  70         if (memcmp(&tboot_uuid, &tboot->uuid, sizeof(tboot->uuid))) {
  71                 pr_warn("tboot at 0x%llx is invalid\n", boot_params.tboot_addr);
  72                 tboot = NULL;
  73                 return;
  74         }
  75         if (tboot->version < 5) {
  76                 pr_warn("tboot version is invalid: %u\n", tboot->version);
  77                 tboot = NULL;
  78                 return;
  79         }
  80
  81         pr_info("found shared page at phys addr 0x%llx:\n",
  82                 boot_params.tboot_addr);
  83         pr_debug("version: %d\n", tboot->version);
  84         pr_debug("log_addr: 0x%08x\n", tboot->log_addr);
  85         pr_debug("shutdown_entry: 0x%x\n", tboot->shutdown_entry);
  86         pr_debug("tboot_base: 0x%08x\n", tboot->tboot_base);
  87         pr_debug("tboot_size: 0x%x\n", tboot->tboot_size);
  88 }
  89
  90 static pgd_t *tboot_pg_dir;
  91 static struct mm_struct tboot_mm = {
  92         .mm_rb          = RB_ROOT,
  93         .pgd            = swapper_pg_dir,
  94         .mm_users       = ATOMIC_INIT(2),
  95         .mm_count       = ATOMIC_INIT(1),
  96         .write_protect_seq = SEQCNT_ZERO(tboot_mm.write_protect_seq),
  97         MMAP_LOCK_INITIALIZER(init_mm)
  98         .page_table_lock =  __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
  99         .mmlist         = LIST_HEAD_INIT(init_mm.mmlist),
 100 };
 101
 102 static inline void switch_to_tboot_pt(void)
 103 {
 104         write_cr3(virt_to_phys(tboot_pg_dir));
 105 }
 106
 107 static int map_tboot_page(unsigned long vaddr, unsigned long pfn,
 108                           pgprot_t prot)
 109 {
 110         pgd_t *pgd;
 111         p4d_t *p4d;
 112         pud_t *pud;
 113         pmd_t *pmd;
 114         pte_t *pte;
 115
 116         pgd = pgd_offset(&tboot_mm, vaddr);
 117         p4d = p4d_alloc(&tboot_mm, pgd, vaddr);
 118         if (!p4d)
 119                 return -1;
 120         pud = pud_alloc(&tboot_mm, p4d, vaddr);
 121         if (!pud)
 122                 return -1;
 123         pmd = pmd_alloc(&tboot_mm, pud, vaddr);
 124         if (!pmd)
 125                 return -1;
 126         pte = pte_alloc_map(&tboot_mm, pmd, vaddr);
 127         if (!pte)
 128                 return -1;
 129         set_pte_at(&tboot_mm, vaddr, pte, pfn_pte(pfn, prot));
 130         pte_unmap(pte);
 131
 132         /*
 133          * PTI poisons low addresses in the kernel page tables in the
 134          * name of making them unusable for userspace.  To execute
 135          * code at such a low address, the poison must be cleared.
 136          *
 137          * Note: 'pgd' actually gets set in p4d_alloc() _or_
 138          * pud_alloc() depending on 4/5-level paging.
 139          */
 140         pgd->pgd &= ~_PAGE_NX;
 141
 142         return 0;
 143 }
 144
 145 static int map_tboot_pages(unsigned long vaddr, unsigned long start_pfn,
 146                            unsigned long nr)
 147 {
 148         /* Reuse the original kernel mapping */
 149         tboot_pg_dir = pgd_alloc(&tboot_mm);
 150         if (!tboot_pg_dir)
 151                 return -1;
 152
 153         for (; nr > 0; nr--, vaddr += PAGE_SIZE, start_pfn++) {
 154                 if (map_tboot_page(vaddr, start_pfn, PAGE_KERNEL_EXEC))
 155                         return -1;
 156         }
 157
 158         return 0;
 159 }
 160
 161 static void tboot_create_trampoline(void)
 162 {
 163         u32 map_base, map_size;
 164
 165         /* Create identity map for tboot shutdown code. */
 166         map_base = PFN_DOWN(tboot->tboot_base);
 167         map_size = PFN_UP(tboot->tboot_size);
 168         if (map_tboot_pages(map_base << PAGE_SHIFT, map_base, map_size))
 169                 panic("tboot: Error mapping tboot pages (mfns) @ 0x%x, 0x%x\n",
 170                       map_base, map_size);
 171 }
 172
 173 #ifdef CONFIG_ACPI_SLEEP
 174
 175 static void add_mac_region(phys_addr_t start, unsigned long size)
 176 {
 177         struct tboot_mac_region *mr;
 178         phys_addr_t end = start + size;
 179
 180         if (tboot->num_mac_regions >= MAX_TB_MAC_REGIONS)
 181                 panic("tboot: Too many MAC regions\n");
 182
 183         if (start && size) {
 184                 mr = &tboot->mac_regions[tboot->num_mac_regions++];
 185                 mr->start = round_down(start, PAGE_SIZE);
 186                 mr->size  = round_up(end, PAGE_SIZE) - mr->start;
 187         }
 188 }
 189
 190 static int tboot_setup_sleep(void)
 191 {
 192         int i;
 193
 194         tboot->num_mac_regions = 0;
 195
 196         for (i = 0; i < e820_table->nr_entries; i++) {
 197                 if ((e820_table->entries[i].type != E820_TYPE_RAM)
 198                  && (e820_table->entries[i].type != E820_TYPE_RESERVED_KERN))
 199                         continue;
 200
 201                 add_mac_region(e820_table->entries[i].addr, e820_table->entries[i].size);
 202         }
 203
 204         tboot->acpi_sinfo.kernel_s3_resume_vector =
 205                 real_mode_header->wakeup_start;
 206
 207         return 0;
 208 }
 209
 210 #else /* no CONFIG_ACPI_SLEEP */
 211
 212 static int tboot_setup_sleep(void)
 213 {
 214         /* S3 shutdown requested, but S3 not supported by the kernel... */
 215         BUG();
 216         return -1;
 217 }
 218
 219 #endif
 220
 221 void tboot_shutdown(u32 shutdown_type)
 222 {
 223         void (*shutdown)(void);
 224
 225         if (!tboot_enabled())
 226                 return;
 227
 228         /*
 229          * if we're being called before the 1:1 mapping is set up then just
 230          * return and let the normal shutdown happen; this should only be
 231          * due to very early panic()
 232          */
 233         if (!tboot_pg_dir)
 234                 return;
 235
 236         /* if this is S3 then set regions to MAC */
 237         if (shutdown_type == TB_SHUTDOWN_S3)
 238                 if (tboot_setup_sleep())
 239                         return;
 240
 241         tboot->shutdown_type = shutdown_type;
 242
 243         switch_to_tboot_pt();
 244
 245         shutdown = (void(*)(void))(unsigned long)tboot->shutdown_entry;
 246         shutdown();
 247
 248         /* should not reach here */
 249         while (1)
 250                 halt();
 251 }
 252
 253 static void tboot_copy_fadt(const struct acpi_table_fadt *fadt)
 254 {
 255 #define TB_COPY_GAS(tbg, g)                     \
 256         tbg.space_id     = g.space_id;          \
 257         tbg.bit_width    = g.bit_width;         \
 258         tbg.bit_offset   = g.bit_offset;        \
 259         tbg.access_width = g.access_width;      \
 260         tbg.address      = g.address;
 261
 262         TB_COPY_GAS(tboot->acpi_sinfo.pm1a_cnt_blk, fadt->xpm1a_control_block);
 263         TB_COPY_GAS(tboot->acpi_sinfo.pm1b_cnt_blk, fadt->xpm1b_control_block);
 264         TB_COPY_GAS(tboot->acpi_sinfo.pm1a_evt_blk, fadt->xpm1a_event_block);
 265         TB_COPY_GAS(tboot->acpi_sinfo.pm1b_evt_blk, fadt->xpm1b_event_block);
 266
 267         /*
 268          * We need phys addr of waking vector, but can't use virt_to_phys() on
 269          * &acpi_gbl_FACS because it is ioremap'ed, so calc from FACS phys
 270          * addr.
 271          */
 272         tboot->acpi_sinfo.wakeup_vector = fadt->facs +
 273                 offsetof(struct acpi_table_facs, firmware_waking_vector);
 274 }
 275
 276 static int tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control)
 277 {
 278         static u32 acpi_shutdown_map[ACPI_S_STATE_COUNT] = {
 279                 /* S0,1,2: */ -1, -1, -1,
 280                 /* S3: */ TB_SHUTDOWN_S3,
 281                 /* S4: */ TB_SHUTDOWN_S4,
 282                 /* S5: */ TB_SHUTDOWN_S5 };
 283
 284         if (!tboot_enabled())
 285                 return 0;
 286
 287         tboot_copy_fadt(&acpi_gbl_FADT);
 288         tboot->acpi_sinfo.pm1a_cnt_val = pm1a_control;
 289         tboot->acpi_sinfo.pm1b_cnt_val = pm1b_control;
 290         /* we always use the 32b wakeup vector */
 291         tboot->acpi_sinfo.vector_width = 32;
 292
 293         if (sleep_state >= ACPI_S_STATE_COUNT ||
 294             acpi_shutdown_map[sleep_state] == -1) {
 295                 pr_warn("unsupported sleep state 0x%x\n", sleep_state);
 296                 return -1;
 297         }
 298
 299         tboot_shutdown(acpi_shutdown_map[sleep_state]);
 300         return 0;
 301 }
 302
 303 static int tboot_extended_sleep(u8 sleep_state, u32 val_a, u32 val_b)
 304 {
 305         if (!tboot_enabled())
 306                 return 0;
 307
 308         pr_warn("tboot is not able to suspend on platforms with reduced hardware sleep (ACPIv5)");
 309         return -ENODEV;
 310 }
 311
 312 static atomic_t ap_wfs_count;
 313
 314 static int tboot_wait_for_aps(int num_aps)
 315 {
 316         unsigned long timeout;
 317
 318         timeout = AP_WAIT_TIMEOUT*HZ;
 319         while (atomic_read((atomic_t *)&tboot->num_in_wfs) != num_aps &&
 320                timeout) {
 321                 mdelay(1);
 322                 timeout--;
 323         }
 324
 325         if (timeout)
 326                 pr_warn("tboot wait for APs timeout\n");
 327
 328         return !(atomic_read((atomic_t *)&tboot->num_in_wfs) == num_aps);
 329 }
 330
 331 static int tboot_dying_cpu(unsigned int cpu)
 332 {
 333         atomic_inc(&ap_wfs_count);
 334         if (num_online_cpus() == 1) {
 335                 if (tboot_wait_for_aps(atomic_read(&ap_wfs_count)))
 336                         return -EBUSY;
 337         }
 338         return 0;
 339 }
 340
 341 #ifdef CONFIG_DEBUG_FS
 342
 343 #define TBOOT_LOG_UUID  { 0x26, 0x25, 0x19, 0xc0, 0x30, 0x6b, 0xb4, 0x4d, \
 344                           0x4c, 0x84, 0xa3, 0xe9, 0x53, 0xb8, 0x81, 0x74 }
 345
 346 #define TBOOT_SERIAL_LOG_ADDR   0x60000
 347 #define TBOOT_SERIAL_LOG_SIZE   0x08000
 348 #define LOG_MAX_SIZE_OFF        16
 349 #define LOG_BUF_OFF             24
 350
 351 static uint8_t tboot_log_uuid[16] = TBOOT_LOG_UUID;
 352
 353 static ssize_t tboot_log_read(struct file *file, char __user *user_buf, size_t count, loff_t *ppos)
 354 {
 355         void __iomem *log_base;
 356         u8 log_uuid[16];
 357         u32 max_size;
 358         void *kbuf;
 359         int ret = -EFAULT;
 360
 361         log_base = ioremap(TBOOT_SERIAL_LOG_ADDR, TBOOT_SERIAL_LOG_SIZE);
 362         if (!log_base)
 363                 return ret;
 364
 365         memcpy_fromio(log_uuid, log_base, sizeof(log_uuid));
 366         if (memcmp(&tboot_log_uuid, log_uuid, sizeof(log_uuid)))
 367                 goto err_iounmap;
 368
 369         max_size = readl(log_base + LOG_MAX_SIZE_OFF);
 370         if (*ppos >= max_size) {
 371                 ret = 0;
 372                 goto err_iounmap;
 373         }
 374
 375         if (*ppos + count > max_size)
 376                 count = max_size - *ppos;
 377
 378         kbuf = kmalloc(count, GFP_KERNEL);
 379         if (!kbuf) {
 380                 ret = -ENOMEM;
 381                 goto err_iounmap;
 382         }
 383
 384         memcpy_fromio(kbuf, log_base + LOG_BUF_OFF + *ppos, count);
 385         if (copy_to_user(user_buf, kbuf, count))
 386                 goto err_kfree;
 387
 388         *ppos += count;
 389
 390         ret = count;
 391
 392 err_kfree:
 393         kfree(kbuf);
 394
 395 err_iounmap:
 396         iounmap(log_base);
 397
 398         return ret;
 399 }
 400
 401 static const struct file_operations tboot_log_fops = {
 402         .read   = tboot_log_read,
 403         .llseek = default_llseek,
 404 };
 405
 406 #endif /* CONFIG_DEBUG_FS */
 407
 408 static __init int tboot_late_init(void)
 409 {
 410         if (!tboot_enabled())
 411                 return 0;
 412
 413         tboot_create_trampoline();
 414
 415         atomic_set(&ap_wfs_count, 0);
 416         cpuhp_setup_state(CPUHP_AP_X86_TBOOT_DYING, "x86/tboot:dying", NULL,
 417                           tboot_dying_cpu);
 418 #ifdef CONFIG_DEBUG_FS
 419         debugfs_create_file("tboot_log", S_IRUSR,
 420                         arch_debugfs_dir, NULL, &tboot_log_fops);
 421 #endif
 422
 423         acpi_os_set_prepare_sleep(&tboot_sleep);
 424         acpi_os_set_prepare_extended_sleep(&tboot_extended_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 || dmar_disabled)
 519                 pr_warn("Forcing Intel-IOMMU to enabled\n");
 520
 521         dmar_disabled = 0;
 522         no_iommu = 0;
 523
 524         return 1;
 525 }