x86/kernel/tboot.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * tboot.c: main implementation of helper functions used by kernel for
0004  *          runtime support of Intel(R) Trusted Execution Technology
0005  *
0006  * Copyright (c) 2006-2009, Intel Corporation
0007  */
0008
0009 #include <linux/init_task.h>
0010 #include <linux/spinlock.h>
0011 #include <linux/export.h>
0012 #include <linux/delay.h>
0013 #include <linux/sched.h>
0014 #include <linux/init.h>
0015 #include <linux/dmar.h>
0016 #include <linux/cpu.h>
0017 #include <linux/pfn.h>
0018 #include <linux/mm.h>
0019 #include <linux/tboot.h>
0020 #include <linux/debugfs.h>
0021
0022 #include <asm/realmode.h>
0023 #include <asm/processor.h>
0024 #include <asm/bootparam.h>
0025 #include <asm/pgalloc.h>
0026 #include <asm/fixmap.h>
0027 #include <asm/proto.h>
0028 #include <asm/setup.h>
0029 #include <asm/e820/api.h>
0030 #include <asm/io.h>
0031
0032 #include "../realmode/rm/wakeup.h"
0033
0034 /* Global pointer to shared data; NULL means no measured launch. */
0035 static struct tboot *tboot __read_mostly;
0036
0037 /* timeout for APs (in secs) to enter wait-for-SIPI state during shutdown */
0038 #define AP_WAIT_TIMEOUT     1
0039
0040 #undef pr_fmt
0041 #define pr_fmt(fmt) "tboot: " fmt
0042
0043 static u8 tboot_uuid[16] __initdata = TBOOT_UUID;
0044
0045 bool tboot_enabled(void)
0046 {
0047     return tboot != NULL;
0048 }
0049
0050 /* noinline to prevent gcc from warning about dereferencing constant fixaddr */
0051 static noinline __init bool check_tboot_version(void)
0052 {
0053     if (memcmp(&tboot_uuid, &tboot->uuid, sizeof(tboot->uuid))) {
0054         pr_warn("tboot at 0x%llx is invalid\n", boot_params.tboot_addr);
0055         return false;
0056     }
0057
0058     if (tboot->version < 5) {
0059         pr_warn("tboot version is invalid: %u\n", tboot->version);
0060         return false;
0061     }
0062
0063     pr_info("found shared page at phys addr 0x%llx:\n",
0064         boot_params.tboot_addr);
0065     pr_debug("version: %d\n", tboot->version);
0066     pr_debug("log_addr: 0x%08x\n", tboot->log_addr);
0067     pr_debug("shutdown_entry: 0x%x\n", tboot->shutdown_entry);
0068     pr_debug("tboot_base: 0x%08x\n", tboot->tboot_base);
0069     pr_debug("tboot_size: 0x%x\n", tboot->tboot_size);
0070
0071     return true;
0072 }
0073
0074 void __init tboot_probe(void)
0075 {
0076     /* Look for valid page-aligned address for shared page. */
0077     if (!boot_params.tboot_addr)
0078         return;
0079     /*
0080      * also verify that it is mapped as we expect it before calling
0081      * set_fixmap(), to reduce chance of garbage value causing crash
0082      */
0083     if (!e820__mapped_any(boot_params.tboot_addr,
0084                  boot_params.tboot_addr, E820_TYPE_RESERVED)) {
0085         pr_warn("non-0 tboot_addr but it is not of type E820_TYPE_RESERVED\n");
0086         return;
0087     }
0088
0089     /* Map and check for tboot UUID. */
0090     set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
0091     tboot = (void *)fix_to_virt(FIX_TBOOT_BASE);
0092     if (!check_tboot_version())
0093         tboot = NULL;
0094 }
0095
0096 static pgd_t *tboot_pg_dir;
0097 static struct mm_struct tboot_mm = {
0098     .mm_rb          = RB_ROOT,
0099     .pgd            = swapper_pg_dir,
0100     .mm_users       = ATOMIC_INIT(2),
0101     .mm_count       = ATOMIC_INIT(1),
0102     .write_protect_seq = SEQCNT_ZERO(tboot_mm.write_protect_seq),
0103     MMAP_LOCK_INITIALIZER(init_mm)
0104     .page_table_lock =  __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
0105     .mmlist         = LIST_HEAD_INIT(init_mm.mmlist),
0106 };
0107
0108 static inline void switch_to_tboot_pt(void)
0109 {
0110     write_cr3(virt_to_phys(tboot_pg_dir));
0111 }
0112
0113 static int map_tboot_page(unsigned long vaddr, unsigned long pfn,
0114               pgprot_t prot)
0115 {
0116     pgd_t *pgd;
0117     p4d_t *p4d;
0118     pud_t *pud;
0119     pmd_t *pmd;
0120     pte_t *pte;
0121
0122     pgd = pgd_offset(&tboot_mm, vaddr);
0123     p4d = p4d_alloc(&tboot_mm, pgd, vaddr);
0124     if (!p4d)
0125         return -1;
0126     pud = pud_alloc(&tboot_mm, p4d, vaddr);
0127     if (!pud)
0128         return -1;
0129     pmd = pmd_alloc(&tboot_mm, pud, vaddr);
0130     if (!pmd)
0131         return -1;
0132     pte = pte_alloc_map(&tboot_mm, pmd, vaddr);
0133     if (!pte)
0134         return -1;
0135     set_pte_at(&tboot_mm, vaddr, pte, pfn_pte(pfn, prot));
0136     pte_unmap(pte);
0137
0138     /*
0139      * PTI poisons low addresses in the kernel page tables in the
0140      * name of making them unusable for userspace.  To execute
0141      * code at such a low address, the poison must be cleared.
0142      *
0143      * Note: 'pgd' actually gets set in p4d_alloc() _or_
0144      * pud_alloc() depending on 4/5-level paging.
0145      */
0146     pgd->pgd &= ~_PAGE_NX;
0147
0148     return 0;
0149 }
0150
0151 static int map_tboot_pages(unsigned long vaddr, unsigned long start_pfn,
0152                unsigned long nr)
0153 {
0154     /* Reuse the original kernel mapping */
0155     tboot_pg_dir = pgd_alloc(&tboot_mm);
0156     if (!tboot_pg_dir)
0157         return -1;
0158
0159     for (; nr > 0; nr--, vaddr += PAGE_SIZE, start_pfn++) {
0160         if (map_tboot_page(vaddr, start_pfn, PAGE_KERNEL_EXEC))
0161             return -1;
0162     }
0163
0164     return 0;
0165 }
0166
0167 static void tboot_create_trampoline(void)
0168 {
0169     u32 map_base, map_size;
0170
0171     /* Create identity map for tboot shutdown code. */
0172     map_base = PFN_DOWN(tboot->tboot_base);
0173     map_size = PFN_UP(tboot->tboot_size);
0174     if (map_tboot_pages(map_base << PAGE_SHIFT, map_base, map_size))
0175         panic("tboot: Error mapping tboot pages (mfns) @ 0x%x, 0x%x\n",
0176               map_base, map_size);
0177 }
0178
0179 #ifdef CONFIG_ACPI_SLEEP
0180
0181 static void add_mac_region(phys_addr_t start, unsigned long size)
0182 {
0183     struct tboot_mac_region *mr;
0184     phys_addr_t end = start + size;
0185
0186     if (tboot->num_mac_regions >= MAX_TB_MAC_REGIONS)
0187         panic("tboot: Too many MAC regions\n");
0188
0189     if (start && size) {
0190         mr = &tboot->mac_regions[tboot->num_mac_regions++];
0191         mr->start = round_down(start, PAGE_SIZE);
0192         mr->size  = round_up(end, PAGE_SIZE) - mr->start;
0193     }
0194 }
0195
0196 static int tboot_setup_sleep(void)
0197 {
0198     int i;
0199
0200     tboot->num_mac_regions = 0;
0201
0202     for (i = 0; i < e820_table->nr_entries; i++) {
0203         if ((e820_table->entries[i].type != E820_TYPE_RAM)
0204          && (e820_table->entries[i].type != E820_TYPE_RESERVED_KERN))
0205             continue;
0206
0207         add_mac_region(e820_table->entries[i].addr, e820_table->entries[i].size);
0208     }
0209
0210     tboot->acpi_sinfo.kernel_s3_resume_vector =
0211         real_mode_header->wakeup_start;
0212
0213     return 0;
0214 }
0215
0216 #else /* no CONFIG_ACPI_SLEEP */
0217
0218 static int tboot_setup_sleep(void)
0219 {
0220     /* S3 shutdown requested, but S3 not supported by the kernel... */
0221     BUG();
0222     return -1;
0223 }
0224
0225 #endif
0226
0227 void tboot_shutdown(u32 shutdown_type)
0228 {
0229     void (*shutdown)(void);
0230
0231     if (!tboot_enabled())
0232         return;
0233
0234     /*
0235      * if we're being called before the 1:1 mapping is set up then just
0236      * return and let the normal shutdown happen; this should only be
0237      * due to very early panic()
0238      */
0239     if (!tboot_pg_dir)
0240         return;
0241
0242     /* if this is S3 then set regions to MAC */
0243     if (shutdown_type == TB_SHUTDOWN_S3)
0244         if (tboot_setup_sleep())
0245             return;
0246
0247     tboot->shutdown_type = shutdown_type;
0248
0249     switch_to_tboot_pt();
0250
0251     shutdown = (void(*)(void))(unsigned long)tboot->shutdown_entry;
0252     shutdown();
0253
0254     /* should not reach here */
0255     while (1)
0256         halt();
0257 }
0258
0259 static void tboot_copy_fadt(const struct acpi_table_fadt *fadt)
0260 {
0261 #define TB_COPY_GAS(tbg, g)         \
0262     tbg.space_id     = g.space_id;      \
0263     tbg.bit_width    = g.bit_width;     \
0264     tbg.bit_offset   = g.bit_offset;    \
0265     tbg.access_width = g.access_width;  \
0266     tbg.address      = g.address;
0267
0268     TB_COPY_GAS(tboot->acpi_sinfo.pm1a_cnt_blk, fadt->xpm1a_control_block);
0269     TB_COPY_GAS(tboot->acpi_sinfo.pm1b_cnt_blk, fadt->xpm1b_control_block);
0270     TB_COPY_GAS(tboot->acpi_sinfo.pm1a_evt_blk, fadt->xpm1a_event_block);
0271     TB_COPY_GAS(tboot->acpi_sinfo.pm1b_evt_blk, fadt->xpm1b_event_block);
0272
0273     /*
0274      * We need phys addr of waking vector, but can't use virt_to_phys() on
0275      * &acpi_gbl_FACS because it is ioremap'ed, so calc from FACS phys
0276      * addr.
0277      */
0278     tboot->acpi_sinfo.wakeup_vector = fadt->facs +
0279         offsetof(struct acpi_table_facs, firmware_waking_vector);
0280 }
0281
0282 static int tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control)
0283 {
0284     static u32 acpi_shutdown_map[ACPI_S_STATE_COUNT] = {
0285         /* S0,1,2: */ -1, -1, -1,
0286         /* S3: */ TB_SHUTDOWN_S3,
0287         /* S4: */ TB_SHUTDOWN_S4,
0288         /* S5: */ TB_SHUTDOWN_S5 };
0289
0290     if (!tboot_enabled())
0291         return 0;
0292
0293     tboot_copy_fadt(&acpi_gbl_FADT);
0294     tboot->acpi_sinfo.pm1a_cnt_val = pm1a_control;
0295     tboot->acpi_sinfo.pm1b_cnt_val = pm1b_control;
0296     /* we always use the 32b wakeup vector */
0297     tboot->acpi_sinfo.vector_width = 32;
0298
0299     if (sleep_state >= ACPI_S_STATE_COUNT ||
0300         acpi_shutdown_map[sleep_state] == -1) {
0301         pr_warn("unsupported sleep state 0x%x\n", sleep_state);
0302         return -1;
0303     }
0304
0305     tboot_shutdown(acpi_shutdown_map[sleep_state]);
0306     return 0;
0307 }
0308
0309 static int tboot_extended_sleep(u8 sleep_state, u32 val_a, u32 val_b)
0310 {
0311     if (!tboot_enabled())
0312         return 0;
0313
0314     pr_warn("tboot is not able to suspend on platforms with reduced hardware sleep (ACPIv5)");
0315     return -ENODEV;
0316 }
0317
0318 static atomic_t ap_wfs_count;
0319
0320 static int tboot_wait_for_aps(int num_aps)
0321 {
0322     unsigned long timeout;
0323
0324     timeout = AP_WAIT_TIMEOUT*HZ;
0325     while (atomic_read((atomic_t *)&tboot->num_in_wfs) != num_aps &&
0326            timeout) {
0327         mdelay(1);
0328         timeout--;
0329     }
0330
0331     if (timeout)
0332         pr_warn("tboot wait for APs timeout\n");
0333
0334     return !(atomic_read((atomic_t *)&tboot->num_in_wfs) == num_aps);
0335 }
0336
0337 static int tboot_dying_cpu(unsigned int cpu)
0338 {
0339     atomic_inc(&ap_wfs_count);
0340     if (num_online_cpus() == 1) {
0341         if (tboot_wait_for_aps(atomic_read(&ap_wfs_count)))
0342             return -EBUSY;
0343     }
0344     return 0;
0345 }
0346
0347 #ifdef CONFIG_DEBUG_FS
0348
0349 #define TBOOT_LOG_UUID  { 0x26, 0x25, 0x19, 0xc0, 0x30, 0x6b, 0xb4, 0x4d, \
0350               0x4c, 0x84, 0xa3, 0xe9, 0x53, 0xb8, 0x81, 0x74 }
0351
0352 #define TBOOT_SERIAL_LOG_ADDR   0x60000
0353 #define TBOOT_SERIAL_LOG_SIZE   0x08000
0354 #define LOG_MAX_SIZE_OFF    16
0355 #define LOG_BUF_OFF     24
0356
0357 static uint8_t tboot_log_uuid[16] = TBOOT_LOG_UUID;
0358
0359 static ssize_t tboot_log_read(struct file *file, char __user *user_buf, size_t count, loff_t *ppos)
0360 {
0361     void __iomem *log_base;
0362     u8 log_uuid[16];
0363     u32 max_size;
0364     void *kbuf;
0365     int ret = -EFAULT;
0366
0367     log_base = ioremap(TBOOT_SERIAL_LOG_ADDR, TBOOT_SERIAL_LOG_SIZE);
0368     if (!log_base)
0369         return ret;
0370
0371     memcpy_fromio(log_uuid, log_base, sizeof(log_uuid));
0372     if (memcmp(&tboot_log_uuid, log_uuid, sizeof(log_uuid)))
0373         goto err_iounmap;
0374
0375     max_size = readl(log_base + LOG_MAX_SIZE_OFF);
0376     if (*ppos >= max_size) {
0377         ret = 0;
0378         goto err_iounmap;
0379     }
0380
0381     if (*ppos + count > max_size)
0382         count = max_size - *ppos;
0383
0384     kbuf = kmalloc(count, GFP_KERNEL);
0385     if (!kbuf) {
0386         ret = -ENOMEM;
0387         goto err_iounmap;
0388     }
0389
0390     memcpy_fromio(kbuf, log_base + LOG_BUF_OFF + *ppos, count);
0391     if (copy_to_user(user_buf, kbuf, count))
0392         goto err_kfree;
0393
0394     *ppos += count;
0395
0396     ret = count;
0397
0398 err_kfree:
0399     kfree(kbuf);
0400
0401 err_iounmap:
0402     iounmap(log_base);
0403
0404     return ret;
0405 }
0406
0407 static const struct file_operations tboot_log_fops = {
0408     .read   = tboot_log_read,
0409     .llseek = default_llseek,
0410 };
0411
0412 #endif /* CONFIG_DEBUG_FS */
0413
0414 static __init int tboot_late_init(void)
0415 {
0416     if (!tboot_enabled())
0417         return 0;
0418
0419     tboot_create_trampoline();
0420
0421     atomic_set(&ap_wfs_count, 0);
0422     cpuhp_setup_state(CPUHP_AP_X86_TBOOT_DYING, "x86/tboot:dying", NULL,
0423               tboot_dying_cpu);
0424 #ifdef CONFIG_DEBUG_FS
0425     debugfs_create_file("tboot_log", S_IRUSR,
0426             arch_debugfs_dir, NULL, &tboot_log_fops);
0427 #endif
0428
0429     acpi_os_set_prepare_sleep(&tboot_sleep);
0430     acpi_os_set_prepare_extended_sleep(&tboot_extended_sleep);
0431     return 0;
0432 }
0433
0434 late_initcall(tboot_late_init);
0435
0436 /*
0437  * TXT configuration registers (offsets from TXT_{PUB, PRIV}_CONFIG_REGS_BASE)
0438  */
0439
0440 #define TXT_PUB_CONFIG_REGS_BASE       0xfed30000
0441 #define TXT_PRIV_CONFIG_REGS_BASE      0xfed20000
0442
0443 /* # pages for each config regs space - used by fixmap */
0444 #define NR_TXT_CONFIG_PAGES     ((TXT_PUB_CONFIG_REGS_BASE -                \
0445                   TXT_PRIV_CONFIG_REGS_BASE) >> PAGE_SHIFT)
0446
0447 /* offsets from pub/priv config space */
0448 #define TXTCR_HEAP_BASE             0x0300
0449 #define TXTCR_HEAP_SIZE             0x0308
0450
0451 #define SHA1_SIZE      20
0452
0453 struct sha1_hash {
0454     u8 hash[SHA1_SIZE];
0455 };
0456
0457 struct sinit_mle_data {
0458     u32               version;             /* currently 6 */
0459     struct sha1_hash  bios_acm_id;
0460     u32               edx_senter_flags;
0461     u64               mseg_valid;
0462     struct sha1_hash  sinit_hash;
0463     struct sha1_hash  mle_hash;
0464     struct sha1_hash  stm_hash;
0465     struct sha1_hash  lcp_policy_hash;
0466     u32               lcp_policy_control;
0467     u32               rlp_wakeup_addr;
0468     u32               reserved;
0469     u32               num_mdrs;
0470     u32               mdrs_off;
0471     u32               num_vtd_dmars;
0472     u32               vtd_dmars_off;
0473 } __packed;
0474
0475 struct acpi_table_header *tboot_get_dmar_table(struct acpi_table_header *dmar_tbl)
0476 {
0477     void *heap_base, *heap_ptr, *config;
0478
0479     if (!tboot_enabled())
0480         return dmar_tbl;
0481
0482     /*
0483      * ACPI tables may not be DMA protected by tboot, so use DMAR copy
0484      * SINIT saved in SinitMleData in TXT heap (which is DMA protected)
0485      */
0486
0487     /* map config space in order to get heap addr */
0488     config = ioremap(TXT_PUB_CONFIG_REGS_BASE, NR_TXT_CONFIG_PAGES *
0489              PAGE_SIZE);
0490     if (!config)
0491         return NULL;
0492
0493     /* now map TXT heap */
0494     heap_base = ioremap(*(u64 *)(config + TXTCR_HEAP_BASE),
0495                 *(u64 *)(config + TXTCR_HEAP_SIZE));
0496     iounmap(config);
0497     if (!heap_base)
0498         return NULL;
0499
0500     /* walk heap to SinitMleData */
0501     /* skip BiosData */
0502     heap_ptr = heap_base + *(u64 *)heap_base;
0503     /* skip OsMleData */
0504     heap_ptr += *(u64 *)heap_ptr;
0505     /* skip OsSinitData */
0506     heap_ptr += *(u64 *)heap_ptr;
0507     /* now points to SinitMleDataSize; set to SinitMleData */
0508     heap_ptr += sizeof(u64);
0509     /* get addr of DMAR table */
0510     dmar_tbl = (struct acpi_table_header *)(heap_ptr +
0511            ((struct sinit_mle_data *)heap_ptr)->vtd_dmars_off -
0512            sizeof(u64));
0513
0514     /* don't unmap heap because dmar.c needs access to this */
0515
0516     return dmar_tbl;
0517 }