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
tboot_enabled(void)47 bool tboot_enabled(void)
48 {
49 return tboot != NULL;
50 }
51
52 /* noinline to prevent gcc from warning about dereferencing constant fixaddr */
check_tboot_version(void)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
tboot_probe(void)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
switch_to_tboot_pt(void)110 static inline void switch_to_tboot_pt(void)
111 {
112 write_cr3(virt_to_phys(tboot_pg_dir));
113 }
114
map_tboot_page(unsigned long vaddr,unsigned long pfn,pgprot_t prot)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
map_tboot_pages(unsigned long vaddr,unsigned long start_pfn,unsigned long nr)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
tboot_create_trampoline(void)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
add_mac_region(phys_addr_t start,unsigned long size)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
tboot_setup_sleep(void)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
tboot_setup_sleep(void)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
tboot_shutdown(u32 shutdown_type)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
tboot_copy_fadt(const struct acpi_table_fadt * fadt)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
tboot_sleep(u8 sleep_state,u32 pm1a_control,u32 pm1b_control)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
tboot_extended_sleep(u8 sleep_state,u32 val_a,u32 val_b)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
tboot_wait_for_aps(int num_aps)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
tboot_dying_cpu(unsigned int cpu)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
tboot_log_read(struct file * file,char __user * user_buf,size_t count,loff_t * ppos)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
tboot_late_init(void)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
tboot_get_dmar_table(struct acpi_table_header * dmar_tbl)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
tboot_force_iommu(void)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 }
534