arch/x86/kernel/tboot.c

   1 /*
   2  * tboot.c: main implementation of helper functions used by kernel for
   3  *          runtime support of Intel(R) Trusted Execution Technology
   4  *
   5  * Copyright (c) 2006-2009, Intel Corporation
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms and conditions of the GNU General Public License,
   9  * version 2, as published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14  * more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along with
  17  * this program; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  */
  21
  22 #include <linux/intel-iommu.h>
  23 #include <linux/init_task.h>
  24 #include <linux/spinlock.h>
  25 #include <linux/export.h>
  26 #include <linux/delay.h>
  27 #include <linux/sched.h>
  28 #include <linux/init.h>
  29 #include <linux/dmar.h>
  30 #include <linux/cpu.h>
  31 #include <linux/pfn.h>
  32 #include <linux/mm.h>
  33 #include <linux/tboot.h>
  34 #include <linux/debugfs.h>
  35
  36 #include <asm/realmode.h>
  37 #include <asm/processor.h>
  38 #include <asm/bootparam.h>
  39 #include <asm/pgtable.h>
  40 #include <asm/pgalloc.h>
  41 #include <asm/swiotlb.h>
  42 #include <asm/fixmap.h>
  43 #include <asm/proto.h>
  44 #include <asm/setup.h>
  45 #include <asm/e820/api.h>
  46 #include <asm/io.h>
  47
  48 #include "../realmode/rm/wakeup.h"
  49
  50 /* Global pointer to shared data; NULL means no measured launch. */
  51 struct tboot *tboot __read_mostly;
  52 EXPORT_SYMBOL(tboot);
  53
  54 /* timeout for APs (in secs) to enter wait-for-SIPI state during shutdown */
  55 #define AP_WAIT_TIMEOUT         1
  56
  57 #undef pr_fmt
  58 #define pr_fmt(fmt)     "tboot: " fmt
  59
  60 static u8 tboot_uuid[16] __initdata = TBOOT_UUID;
  61
  62 void __init tboot_probe(void)
  63 {
  64         /* Look for valid page-aligned address for shared page. */
  65         if (!boot_params.tboot_addr)
  66                 return;
  67         /*
  68          * also verify that it is mapped as we expect it before calling
  69          * set_fixmap(), to reduce chance of garbage value causing crash
  70          */
  71         if (!e820__mapped_any(boot_params.tboot_addr,
  72                              boot_params.tboot_addr, E820_TYPE_RESERVED)) {
  73                 pr_warning("non-0 tboot_addr but it is not of type E820_TYPE_RESERVED\n");
  74                 return;
  75         }
  76
  77         /* Map and check for tboot UUID. */
  78         set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
  79         tboot = (struct tboot *)fix_to_virt(FIX_TBOOT_BASE);
  80         if (memcmp(&tboot_uuid, &tboot->uuid, sizeof(tboot->uuid))) {
  81                 pr_warning("tboot at 0x%llx is invalid\n",
  82                            boot_params.tboot_addr);
  83                 tboot = NULL;
  84                 return;
  85         }
  86         if (tboot->version < 5) {
  87                 pr_warning("tboot version is invalid: %u\n", tboot->version);
  88                 tboot = NULL;
  89                 return;
  90         }
  91
  92         pr_info("found shared page at phys addr 0x%llx:\n",
  93                 boot_params.tboot_addr);
  94         pr_debug("version: %d\n", tboot->version);
  95         pr_debug("log_addr: 0x%08x\n", tboot->log_addr);
  96         pr_debug("shutdown_entry: 0x%x\n", tboot->shutdown_entry);
  97         pr_debug("tboot_base: 0x%08x\n", tboot->tboot_base);
  98         pr_debug("tboot_size: 0x%x\n", tboot->tboot_size);
  99 }
 100
 101 static pgd_t *tboot_pg_dir;
 102 static struct mm_struct tboot_mm = {
 103         .mm_rb          = RB_ROOT,
 104         .pgd            = swapper_pg_dir,
 105         .mm_users       = ATOMIC_INIT(2),
 106         .mm_count       = ATOMIC_INIT(1),
 107         .mmap_sem       = __RWSEM_INITIALIZER(init_mm.mmap_sem),
 108         .page_table_lock =  __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
 109         .mmlist         = LIST_HEAD_INIT(init_mm.mmlist),
 110 };
 111
 112 static inline void switch_to_tboot_pt(void)
 113 {
 114         write_cr3(virt_to_phys(tboot_pg_dir));
 115 }
 116
 117 static int map_tboot_page(unsigned long vaddr, unsigned long pfn,
 118                           pgprot_t prot)
 119 {
 120         pgd_t *pgd;
 121         p4d_t *p4d;
 122         pud_t *pud;
 123         pmd_t *pmd;
 124         pte_t *pte;
 125
 126         pgd = pgd_offset(&tboot_mm, vaddr);
 127         p4d = p4d_alloc(&tboot_mm, pgd, vaddr);
 128         if (!p4d)
 129                 return -1;
 130         pud = pud_alloc(&tboot_mm, p4d, vaddr);
 131         if (!pud)
 132                 return -1;
 133         pmd = pmd_alloc(&tboot_mm, pud, vaddr);
 134         if (!pmd)
 135                 return -1;
 136         pte = pte_alloc_map(&tboot_mm, pmd, vaddr);
 137         if (!pte)
 138                 return -1;
 139         set_pte_at(&tboot_mm, vaddr, pte, pfn_pte(pfn, prot));
 140         pte_unmap(pte);
 141
 142         /*
 143          * PTI poisons low addresses in the kernel page tables in the
 144          * name of making them unusable for userspace.  To execute
 145          * code at such a low address, the poison must be cleared.
 146          *
 147          * Note: 'pgd' actually gets set in p4d_alloc() _or_
 148          * pud_alloc() depending on 4/5-level paging.
 149          */
 150         pgd->pgd &= ~_PAGE_NX;
 151
 152         return 0;
 153 }
 154
 155 static int map_tboot_pages(unsigned long vaddr, unsigned long start_pfn,
 156                            unsigned long nr)
 157 {
 158         /* Reuse the original kernel mapping */
 159         tboot_pg_dir = pgd_alloc(&tboot_mm);
 160         if (!tboot_pg_dir)
 161                 return -1;
 162
 163         for (; nr > 0; nr--, vaddr += PAGE_SIZE, start_pfn++) {
 164                 if (map_tboot_page(vaddr, start_pfn, PAGE_KERNEL_EXEC))
 165                         return -1;
 166         }
 167
 168         return 0;
 169 }
 170
 171 static void tboot_create_trampoline(void)
 172 {
 173         u32 map_base, map_size;
 174
 175         /* Create identity map for tboot shutdown code. */
 176         map_base = PFN_DOWN(tboot->tboot_base);
 177         map_size = PFN_UP(tboot->tboot_size);
 178         if (map_tboot_pages(map_base << PAGE_SHIFT, map_base, map_size))
 179                 panic("tboot: Error mapping tboot pages (mfns) @ 0x%x, 0x%x\n",
 180                       map_base, map_size);
 181 }
 182
 183 #ifdef CONFIG_ACPI_SLEEP
 184
 185 static void add_mac_region(phys_addr_t start, unsigned long size)
 186 {
 187         struct tboot_mac_region *mr;
 188         phys_addr_t end = start + size;
 189
 190         if (tboot->num_mac_regions >= MAX_TB_MAC_REGIONS)
 191                 panic("tboot: Too many MAC regions\n");
 192
 193         if (start && size) {
 194                 mr = &tboot->mac_regions[tboot->num_mac_regions++];
 195                 mr->start = round_down(start, PAGE_SIZE);
 196                 mr->size  = round_up(end, PAGE_SIZE) - mr->start;
 197         }
 198 }
 199
 200 static int tboot_setup_sleep(void)
 201 {
 202         int i;
 203
 204         tboot->num_mac_regions = 0;
 205
 206         for (i = 0; i < e820_table->nr_entries; i++) {
 207                 if ((e820_table->entries[i].type != E820_TYPE_RAM)
 208                  && (e820_table->entries[i].type != E820_TYPE_RESERVED_KERN))
 209                         continue;
 210
 211                 add_mac_region(e820_table->entries[i].addr, e820_table->entries[i].size);
 212         }
 213
 214         tboot->acpi_sinfo.kernel_s3_resume_vector =
 215                 real_mode_header->wakeup_start;
 216
 217         return 0;
 218 }
 219
 220 #else /* no CONFIG_ACPI_SLEEP */
 221
 222 static int tboot_setup_sleep(void)
 223 {
 224         /* S3 shutdown requested, but S3 not supported by the kernel... */
 225         BUG();
 226         return -1;
 227 }
 228
 229 #endif
 230
 231 void tboot_shutdown(u32 shutdown_type)
 232 {
 233         void (*shutdown)(void);
 234
 235         if (!tboot_enabled())
 236                 return;
 237
 238         /*
 239          * if we're being called before the 1:1 mapping is set up then just
 240          * return and let the normal shutdown happen; this should only be
 241          * due to very early panic()
 242          */
 243         if (!tboot_pg_dir)
 244                 return;
 245
 246         /* if this is S3 then set regions to MAC */
 247         if (shutdown_type == TB_SHUTDOWN_S3)
 248                 if (tboot_setup_sleep())
 249                         return;
 250
 251         tboot->shutdown_type = shutdown_type;
 252
 253         switch_to_tboot_pt();
 254
 255         shutdown = (void(*)(void))(unsigned long)tboot->shutdown_entry;
 256         shutdown();
 257
 258         /* should not reach here */
 259         while (1)
 260                 halt();
 261 }
 262
 263 static void tboot_copy_fadt(const struct acpi_table_fadt *fadt)
 264 {
 265 #define TB_COPY_GAS(tbg, g)                     \
 266         tbg.space_id     = g.space_id;          \
 267         tbg.bit_width    = g.bit_width;         \
 268         tbg.bit_offset   = g.bit_offset;        \
 269         tbg.access_width = g.access_width;      \
 270         tbg.address      = g.address;
 271
 272         TB_COPY_GAS(tboot->acpi_sinfo.pm1a_cnt_blk, fadt->xpm1a_control_block);
 273         TB_COPY_GAS(tboot->acpi_sinfo.pm1b_cnt_blk, fadt->xpm1b_control_block);
 274         TB_COPY_GAS(tboot->acpi_sinfo.pm1a_evt_blk, fadt->xpm1a_event_block);
 275         TB_COPY_GAS(tboot->acpi_sinfo.pm1b_evt_blk, fadt->xpm1b_event_block);
 276
 277         /*
 278          * We need phys addr of waking vector, but can't use virt_to_phys() on
 279          * &acpi_gbl_FACS because it is ioremap'ed, so calc from FACS phys
 280          * addr.
 281          */
 282         tboot->acpi_sinfo.wakeup_vector = fadt->facs +
 283                 offsetof(struct acpi_table_facs, firmware_waking_vector);
 284 }
 285
 286 static int tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control)
 287 {
 288         static u32 acpi_shutdown_map[ACPI_S_STATE_COUNT] = {
 289                 /* S0,1,2: */ -1, -1, -1,
 290                 /* S3: */ TB_SHUTDOWN_S3,
 291                 /* S4: */ TB_SHUTDOWN_S4,
 292                 /* S5: */ TB_SHUTDOWN_S5 };
 293
 294         if (!tboot_enabled())
 295                 return 0;
 296
 297         tboot_copy_fadt(&acpi_gbl_FADT);
 298         tboot->acpi_sinfo.pm1a_cnt_val = pm1a_control;
 299         tboot->acpi_sinfo.pm1b_cnt_val = pm1b_control;
 300         /* we always use the 32b wakeup vector */
 301         tboot->acpi_sinfo.vector_width = 32;
 302
 303         if (sleep_state >= ACPI_S_STATE_COUNT ||
 304             acpi_shutdown_map[sleep_state] == -1) {
 305                 pr_warning("unsupported sleep state 0x%x\n", sleep_state);
 306                 return -1;
 307         }
 308
 309         tboot_shutdown(acpi_shutdown_map[sleep_state]);
 310         return 0;
 311 }
 312
 313 static int tboot_extended_sleep(u8 sleep_state, u32 val_a, u32 val_b)
 314 {
 315         if (!tboot_enabled())
 316                 return 0;
 317
 318         pr_warning("tboot is not able to suspend on platforms with reduced hardware sleep (ACPIv5)");
 319         return -ENODEV;
 320 }
 321
 322 static atomic_t ap_wfs_count;
 323
 324 static int tboot_wait_for_aps(int num_aps)
 325 {
 326         unsigned long timeout;
 327
 328         timeout = AP_WAIT_TIMEOUT*HZ;
 329         while (atomic_read((atomic_t *)&tboot->num_in_wfs) != num_aps &&
 330                timeout) {
 331                 mdelay(1);
 332                 timeout--;
 333         }
 334
 335         if (timeout)
 336                 pr_warning("tboot wait for APs timeout\n");
 337
 338         return !(atomic_read((atomic_t *)&tboot->num_in_wfs) == num_aps);
 339 }
 340
 341 static int tboot_dying_cpu(unsigned int cpu)
 342 {
 343         atomic_inc(&ap_wfs_count);
 344         if (num_online_cpus() == 1) {
 345                 if (tboot_wait_for_aps(atomic_read(&ap_wfs_count)))
 346                         return -EBUSY;
 347         }
 348         return 0;
 349 }
 350
 351 #ifdef CONFIG_DEBUG_FS
 352
 353 #define TBOOT_LOG_UUID  { 0x26, 0x25, 0x19, 0xc0, 0x30, 0x6b, 0xb4, 0x4d, \
 354                           0x4c, 0x84, 0xa3, 0xe9, 0x53, 0xb8, 0x81, 0x74 }
 355
 356 #define TBOOT_SERIAL_LOG_ADDR   0x60000
 357 #define TBOOT_SERIAL_LOG_SIZE   0x08000
 358 #define LOG_MAX_SIZE_OFF        16
 359 #define LOG_BUF_OFF             24
 360
 361 static uint8_t tboot_log_uuid[16] = TBOOT_LOG_UUID;
 362
 363 static ssize_t tboot_log_read(struct file *file, char __user *user_buf, size_t count, loff_t *ppos)
 364 {
 365         void __iomem *log_base;
 366         u8 log_uuid[16];
 367         u32 max_size;
 368         void *kbuf;
 369         int ret = -EFAULT;
 370
 371         log_base = ioremap_nocache(TBOOT_SERIAL_LOG_ADDR, TBOOT_SERIAL_LOG_SIZE);
 372         if (!log_base)
 373                 return ret;
 374
 375         memcpy_fromio(log_uuid, log_base, sizeof(log_uuid));
 376         if (memcmp(&tboot_log_uuid, log_uuid, sizeof(log_uuid)))
 377                 goto err_iounmap;
 378
 379         max_size = readl(log_base + LOG_MAX_SIZE_OFF);
 380         if (*ppos >= max_size) {
 381                 ret = 0;
 382                 goto err_iounmap;
 383         }
 384
 385         if (*ppos + count > max_size)
 386                 count = max_size - *ppos;
 387
 388         kbuf = kmalloc(count, GFP_KERNEL);
 389         if (!kbuf) {
 390                 ret = -ENOMEM;
 391                 goto err_iounmap;
 392         }
 393
 394         memcpy_fromio(kbuf, log_base + LOG_BUF_OFF + *ppos, count);
 395         if (copy_to_user(user_buf, kbuf, count))
 396                 goto err_kfree;
 397
 398         *ppos += count;
 399
 400         ret = count;
 401
 402 err_kfree:
 403         kfree(kbuf);
 404
 405 err_iounmap:
 406         iounmap(log_base);
 407
 408         return ret;
 409 }
 410
 411 static const struct file_operations tboot_log_fops = {
 412         .read   = tboot_log_read,
 413         .llseek = default_llseek,
 414 };
 415
 416 #endif /* CONFIG_DEBUG_FS */
 417
 418 static __init int tboot_late_init(void)
 419 {
 420         if (!tboot_enabled())
 421                 return 0;
 422
 423         tboot_create_trampoline();
 424
 425         atomic_set(&ap_wfs_count, 0);
 426         cpuhp_setup_state(CPUHP_AP_X86_TBOOT_DYING, "x86/tboot:dying", NULL,
 427                           tboot_dying_cpu);
 428 #ifdef CONFIG_DEBUG_FS
 429         debugfs_create_file("tboot_log", S_IRUSR,
 430                         arch_debugfs_dir, NULL, &tboot_log_fops);
 431 #endif
 432
 433         acpi_os_set_prepare_sleep(&tboot_sleep);
 434         acpi_os_set_prepare_extended_sleep(&tboot_extended_sleep);
 435         return 0;
 436 }
 437
 438 late_initcall(tboot_late_init);
 439
 440 /*
 441  * TXT configuration registers (offsets from TXT_{PUB, PRIV}_CONFIG_REGS_BASE)
 442  */
 443
 444 #define TXT_PUB_CONFIG_REGS_BASE       0xfed30000
 445 #define TXT_PRIV_CONFIG_REGS_BASE      0xfed20000
 446
 447 /* # pages for each config regs space - used by fixmap */
 448 #define NR_TXT_CONFIG_PAGES     ((TXT_PUB_CONFIG_REGS_BASE -                \
 449                                   TXT_PRIV_CONFIG_REGS_BASE) >> PAGE_SHIFT)
 450
 451 /* offsets from pub/priv config space */
 452 #define TXTCR_HEAP_BASE             0x0300
 453 #define TXTCR_HEAP_SIZE             0x0308
 454
 455 #define SHA1_SIZE      20
 456
 457 struct sha1_hash {
 458         u8 hash[SHA1_SIZE];
 459 };
 460
 461 struct sinit_mle_data {
 462         u32               version;             /* currently 6 */
 463         struct sha1_hash  bios_acm_id;
 464         u32               edx_senter_flags;
 465         u64               mseg_valid;
 466         struct sha1_hash  sinit_hash;
 467         struct sha1_hash  mle_hash;
 468         struct sha1_hash  stm_hash;
 469         struct sha1_hash  lcp_policy_hash;
 470         u32               lcp_policy_control;
 471         u32               rlp_wakeup_addr;
 472         u32               reserved;
 473         u32               num_mdrs;
 474         u32               mdrs_off;
 475         u32               num_vtd_dmars;
 476         u32               vtd_dmars_off;
 477 } __packed;
 478
 479 struct acpi_table_header *tboot_get_dmar_table(struct acpi_table_header *dmar_tbl)
 480 {
 481         void *heap_base, *heap_ptr, *config;
 482
 483         if (!tboot_enabled())
 484                 return dmar_tbl;
 485
 486         /*
 487          * ACPI tables may not be DMA protected by tboot, so use DMAR copy
 488          * SINIT saved in SinitMleData in TXT heap (which is DMA protected)
 489          */
 490
 491         /* map config space in order to get heap addr */
 492         config = ioremap(TXT_PUB_CONFIG_REGS_BASE, NR_TXT_CONFIG_PAGES *
 493                          PAGE_SIZE);
 494         if (!config)
 495                 return NULL;
 496
 497         /* now map TXT heap */
 498         heap_base = ioremap(*(u64 *)(config + TXTCR_HEAP_BASE),
 499                             *(u64 *)(config + TXTCR_HEAP_SIZE));
 500         iounmap(config);
 501         if (!heap_base)
 502                 return NULL;
 503
 504         /* walk heap to SinitMleData */
 505         /* skip BiosData */
 506         heap_ptr = heap_base + *(u64 *)heap_base;
 507         /* skip OsMleData */
 508         heap_ptr += *(u64 *)heap_ptr;
 509         /* skip OsSinitData */
 510         heap_ptr += *(u64 *)heap_ptr;
 511         /* now points to SinitMleDataSize; set to SinitMleData */
 512         heap_ptr += sizeof(u64);
 513         /* get addr of DMAR table */
 514         dmar_tbl = (struct acpi_table_header *)(heap_ptr +
 515                    ((struct sinit_mle_data *)heap_ptr)->vtd_dmars_off -
 516                    sizeof(u64));
 517
 518         /* don't unmap heap because dmar.c needs access to this */
 519
 520         return dmar_tbl;
 521 }
 522
 523 int tboot_force_iommu(void)
 524 {
 525         if (!tboot_enabled())
 526                 return 0;
 527
 528         if (intel_iommu_tboot_noforce)
 529                 return 1;
 530
 531         if (no_iommu || swiotlb || dmar_disabled)
 532                 pr_warning("Forcing Intel-IOMMU to enabled\n");
 533
 534         dmar_disabled = 0;
 535 #ifdef CONFIG_SWIOTLB
 536         swiotlb = 0;
 537 #endif
 538         no_iommu = 0;
 539
 540         return 1;
 541 }