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Linux/arch/x86/kernel/tboot.c

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

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