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