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