tboot.c

  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. */
 35static 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
 43static u8 tboot_uuid[16] __initdata = TBOOT_UUID;
 44
 45bool tboot_enabled(void)
 46{
 47	return tboot != NULL;
 48}
 49
 50/* noinline to prevent gcc from warning about dereferencing constant fixaddr */
 51static 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
 74void __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
 96static pgd_t *tboot_pg_dir;
 97static 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
108static inline void switch_to_tboot_pt(void)
109{
110	write_cr3(virt_to_phys(tboot_pg_dir));
111}
112
113static 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
151static 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
167static 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
181static 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
196static 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
217static 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
226void 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
258static 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
281static 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
308static 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
317static atomic_t ap_wfs_count;
318
319static 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
336static 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
356static uint8_t tboot_log_uuid[16] = TBOOT_LOG_UUID;
357
358static 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
397err_kfree:
398	kfree(kbuf);
399
400err_iounmap:
401	iounmap(log_base);
402
403	return ret;
404}
405
406static const struct file_operations tboot_log_fops = {
407	.read	= tboot_log_read,
408	.llseek	= default_llseek,
409};
410
411#endif /* CONFIG_DEBUG_FS */
412
413static __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
433late_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
452struct sha1_hash {
453	u8 hash[SHA1_SIZE];
454};
455
456struct 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
474struct 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}