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(p: &tboot_uuid, q: &tboot->uuid, size: 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(start: boot_params.tboot_addr,
84 end: boot_params.tboot_addr, type: 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(idx: 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(address: 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(mm: &tboot_mm, pgd, address: vaddr);
124 if (!p4d)
125 return -1;
126 pud = pud_alloc(mm: &tboot_mm, p4d, address: vaddr);
127 if (!pud)
128 return -1;
129 pmd = pmd_alloc(mm: &tboot_mm, pud, address: 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, pfn: 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(vaddr: map_base << PAGE_SHIFT, start_pfn: map_base, nr: map_size))
175 panic(fmt: "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(fmt: "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 && (e820_table->entries[i].type != E820_TYPE_RESERVED_KERN))
205 continue;
206
207 add_mac_region(start: e820_table->entries[i].addr, size: e820_table->entries[i].size);
208 }
209
210 tboot->acpi_sinfo.kernel_s3_resume_vector =
211 real_mode_header->wakeup_start;
212
213 return 0;
214}
215
216#else /* no CONFIG_ACPI_SLEEP */
217
218static int tboot_setup_sleep(void)
219{
220 /* S3 shutdown requested, but S3 not supported by the kernel... */
221 BUG();
222 return -1;
223}
224
225#endif
226
227void tboot_shutdown(u32 shutdown_type)
228{
229 void (*shutdown)(void);
230
231 if (!tboot_enabled())
232 return;
233
234 /*
235 * if we're being called before the 1:1 mapping is set up then just
236 * return and let the normal shutdown happen; this should only be
237 * due to very early panic()
238 */
239 if (!tboot_pg_dir)
240 return;
241
242 /* if this is S3 then set regions to MAC */
243 if (shutdown_type == TB_SHUTDOWN_S3)
244 if (tboot_setup_sleep())
245 return;
246
247 tboot->shutdown_type = shutdown_type;
248
249 switch_to_tboot_pt();
250
251 shutdown = (void(*)(void))(unsigned long)tboot->shutdown_entry;
252 shutdown();
253
254 /* should not reach here */
255 while (1)
256 halt();
257}
258
259static void tboot_copy_fadt(const struct acpi_table_fadt *fadt)
260{
261#define TB_COPY_GAS(tbg, g) \
262 tbg.space_id = g.space_id; \
263 tbg.bit_width = g.bit_width; \
264 tbg.bit_offset = g.bit_offset; \
265 tbg.access_width = g.access_width; \
266 tbg.address = g.address;
267
268 TB_COPY_GAS(tboot->acpi_sinfo.pm1a_cnt_blk, fadt->xpm1a_control_block);
269 TB_COPY_GAS(tboot->acpi_sinfo.pm1b_cnt_blk, fadt->xpm1b_control_block);
270 TB_COPY_GAS(tboot->acpi_sinfo.pm1a_evt_blk, fadt->xpm1a_event_block);
271 TB_COPY_GAS(tboot->acpi_sinfo.pm1b_evt_blk, fadt->xpm1b_event_block);
272
273 /*
274 * We need phys addr of waking vector, but can't use virt_to_phys() on
275 * &acpi_gbl_FACS because it is ioremap'ed, so calc from FACS phys
276 * addr.
277 */
278 tboot->acpi_sinfo.wakeup_vector = fadt->facs +
279 offsetof(struct acpi_table_facs, firmware_waking_vector);
280}
281
282static int tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control)
283{
284 static u32 acpi_shutdown_map[ACPI_S_STATE_COUNT] = {
285 /* S0,1,2: */ -1, -1, -1,
286 /* S3: */ TB_SHUTDOWN_S3,
287 /* S4: */ TB_SHUTDOWN_S4,
288 /* S5: */ TB_SHUTDOWN_S5 };
289
290 if (!tboot_enabled())
291 return 0;
292
293 tboot_copy_fadt(fadt: &acpi_gbl_FADT);
294 tboot->acpi_sinfo.pm1a_cnt_val = pm1a_control;
295 tboot->acpi_sinfo.pm1b_cnt_val = pm1b_control;
296 /* we always use the 32b wakeup vector */
297 tboot->acpi_sinfo.vector_width = 32;
298
299 if (sleep_state >= ACPI_S_STATE_COUNT ||
300 acpi_shutdown_map[sleep_state] == -1) {
301 pr_warn("unsupported sleep state 0x%x\n", sleep_state);
302 return -1;
303 }
304
305 tboot_shutdown(shutdown_type: acpi_shutdown_map[sleep_state]);
306 return 0;
307}
308
309static int tboot_extended_sleep(u8 sleep_state, u32 val_a, u32 val_b)
310{
311 if (!tboot_enabled())
312 return 0;
313
314 pr_warn("tboot is not able to suspend on platforms with reduced hardware sleep (ACPIv5)");
315 return -ENODEV;
316}
317
318static atomic_t ap_wfs_count;
319
320static int tboot_wait_for_aps(int num_aps)
321{
322 unsigned long timeout;
323
324 timeout = AP_WAIT_TIMEOUT*HZ;
325 while (atomic_read(v: (atomic_t *)&tboot->num_in_wfs) != num_aps &&
326 timeout) {
327 mdelay(1);
328 timeout--;
329 }
330
331 if (timeout)
332 pr_warn("tboot wait for APs timeout\n");
333
334 return !(atomic_read(v: (atomic_t *)&tboot->num_in_wfs) == num_aps);
335}
336
337static int tboot_dying_cpu(unsigned int cpu)
338{
339 atomic_inc(v: &ap_wfs_count);
340 if (num_online_cpus() == 1) {
341 if (tboot_wait_for_aps(num_aps: atomic_read(v: &ap_wfs_count)))
342 return -EBUSY;
343 }
344 return 0;
345}
346
347#ifdef CONFIG_DEBUG_FS
348
349#define TBOOT_LOG_UUID { 0x26, 0x25, 0x19, 0xc0, 0x30, 0x6b, 0xb4, 0x4d, \
350 0x4c, 0x84, 0xa3, 0xe9, 0x53, 0xb8, 0x81, 0x74 }
351
352#define TBOOT_SERIAL_LOG_ADDR 0x60000
353#define TBOOT_SERIAL_LOG_SIZE 0x08000
354#define LOG_MAX_SIZE_OFF 16
355#define LOG_BUF_OFF 24
356
357static uint8_t tboot_log_uuid[16] = TBOOT_LOG_UUID;
358
359static ssize_t tboot_log_read(struct file *file, char __user *user_buf, size_t count, loff_t *ppos)
360{
361 void __iomem *log_base;
362 u8 log_uuid[16];
363 u32 max_size;
364 void *kbuf;
365 int ret = -EFAULT;
366
367 log_base = ioremap(TBOOT_SERIAL_LOG_ADDR, TBOOT_SERIAL_LOG_SIZE);
368 if (!log_base)
369 return ret;
370
371 memcpy_fromio(log_uuid, log_base, sizeof(log_uuid));
372 if (memcmp(p: &tboot_log_uuid, q: log_uuid, size: sizeof(log_uuid)))
373 goto err_iounmap;
374
375 max_size = readl(addr: log_base + LOG_MAX_SIZE_OFF);
376 if (*ppos >= max_size) {
377 ret = 0;
378 goto err_iounmap;
379 }
380
381 if (*ppos + count > max_size)
382 count = max_size - *ppos;
383
384 kbuf = kmalloc(size: count, GFP_KERNEL);
385 if (!kbuf) {
386 ret = -ENOMEM;
387 goto err_iounmap;
388 }
389
390 memcpy_fromio(kbuf, log_base + LOG_BUF_OFF + *ppos, count);
391 if (copy_to_user(to: user_buf, from: kbuf, n: count))
392 goto err_kfree;
393
394 *ppos += count;
395
396 ret = count;
397
398err_kfree:
399 kfree(objp: kbuf);
400
401err_iounmap:
402 iounmap(addr: log_base);
403
404 return ret;
405}
406
407static const struct file_operations tboot_log_fops = {
408 .read = tboot_log_read,
409 .llseek = default_llseek,
410};
411
412#endif /* CONFIG_DEBUG_FS */
413
414static __init int tboot_late_init(void)
415{
416 if (!tboot_enabled())
417 return 0;
418
419 tboot_create_trampoline();
420
421 atomic_set(v: &ap_wfs_count, i: 0);
422 cpuhp_setup_state(state: CPUHP_AP_X86_TBOOT_DYING, name: "x86/tboot:dying", NULL,
423 teardown: tboot_dying_cpu);
424#ifdef CONFIG_DEBUG_FS
425 debugfs_create_file(name: "tboot_log", S_IRUSR,
426 parent: arch_debugfs_dir, NULL, fops: &tboot_log_fops);
427#endif
428
429 acpi_os_set_prepare_sleep(func: &tboot_sleep);
430 acpi_os_set_prepare_extended_sleep(func: &tboot_extended_sleep);
431 return 0;
432}
433
434late_initcall(tboot_late_init);
435
436/*
437 * TXT configuration registers (offsets from TXT_{PUB, PRIV}_CONFIG_REGS_BASE)
438 */
439
440#define TXT_PUB_CONFIG_REGS_BASE 0xfed30000
441#define TXT_PRIV_CONFIG_REGS_BASE 0xfed20000
442
443/* # pages for each config regs space - used by fixmap */
444#define NR_TXT_CONFIG_PAGES ((TXT_PUB_CONFIG_REGS_BASE - \
445 TXT_PRIV_CONFIG_REGS_BASE) >> PAGE_SHIFT)
446
447/* offsets from pub/priv config space */
448#define TXTCR_HEAP_BASE 0x0300
449#define TXTCR_HEAP_SIZE 0x0308
450
451#define SHA1_SIZE 20
452
453struct sha1_hash {
454 u8 hash[SHA1_SIZE];
455};
456
457struct sinit_mle_data {
458 u32 version; /* currently 6 */
459 struct sha1_hash bios_acm_id;
460 u32 edx_senter_flags;
461 u64 mseg_valid;
462 struct sha1_hash sinit_hash;
463 struct sha1_hash mle_hash;
464 struct sha1_hash stm_hash;
465 struct sha1_hash lcp_policy_hash;
466 u32 lcp_policy_control;
467 u32 rlp_wakeup_addr;
468 u32 reserved;
469 u32 num_mdrs;
470 u32 mdrs_off;
471 u32 num_vtd_dmars;
472 u32 vtd_dmars_off;
473} __packed;
474
475struct acpi_table_header *tboot_get_dmar_table(struct acpi_table_header *dmar_tbl)
476{
477 void *heap_base, *heap_ptr, *config;
478
479 if (!tboot_enabled())
480 return dmar_tbl;
481
482 /*
483 * ACPI tables may not be DMA protected by tboot, so use DMAR copy
484 * SINIT saved in SinitMleData in TXT heap (which is DMA protected)
485 */
486
487 /* map config space in order to get heap addr */
488 config = ioremap(TXT_PUB_CONFIG_REGS_BASE, NR_TXT_CONFIG_PAGES *
489 PAGE_SIZE);
490 if (!config)
491 return NULL;
492
493 /* now map TXT heap */
494 heap_base = ioremap(offset: *(u64 *)(config + TXTCR_HEAP_BASE),
495 size: *(u64 *)(config + TXTCR_HEAP_SIZE));
496 iounmap(addr: config);
497 if (!heap_base)
498 return NULL;
499
500 /* walk heap to SinitMleData */
501 /* skip BiosData */
502 heap_ptr = heap_base + *(u64 *)heap_base;
503 /* skip OsMleData */
504 heap_ptr += *(u64 *)heap_ptr;
505 /* skip OsSinitData */
506 heap_ptr += *(u64 *)heap_ptr;
507 /* now points to SinitMleDataSize; set to SinitMleData */
508 heap_ptr += sizeof(u64);
509 /* get addr of DMAR table */
510 dmar_tbl = (struct acpi_table_header *)(heap_ptr +
511 ((struct sinit_mle_data *)heap_ptr)->vtd_dmars_off -
512 sizeof(u64));
513
514 /* don't unmap heap because dmar.c needs access to this */
515
516 return dmar_tbl;
517}
518

source code of linux/arch/x86/kernel/tboot.c