1 /*
2 * tboot.c: main implementation of helper functions used by kernel for
3 * runtime support of Intel(R) Trusted Execution Technology
4 *
5 * Copyright (c) 2006-2009, Intel Corporation
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms and conditions of the GNU General Public License,
9 * version 2, as published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
14 * more details.
15 *
16 * You should have received a copy of the GNU General Public License along with
17 * this program; if not, write to the Free Software Foundation, Inc.,
18 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 */
21
22 #include <linux/dma_remapping.h>
23 #include <linux/init_task.h>
24 #include <linux/spinlock.h>
25 #include <linux/export.h>
26 #include <linux/delay.h>
27 #include <linux/sched.h>
28 #include <linux/init.h>
29 #include <linux/dmar.h>
30 #include <linux/cpu.h>
31 #include <linux/pfn.h>
32 #include <linux/mm.h>
33 #include <linux/tboot.h>
34 #include <linux/debugfs.h>
35
36 #include <asm/realmode.h>
37 #include <asm/processor.h>
38 #include <asm/bootparam.h>
39 #include <asm/pgtable.h>
40 #include <asm/pgalloc.h>
41 #include <asm/swiotlb.h>
42 #include <asm/fixmap.h>
43 #include <asm/proto.h>
44 #include <asm/setup.h>
45 #include <asm/e820.h>
46 #include <asm/io.h>
47
48 #include "../realmode/rm/wakeup.h"
49
50 /* Global pointer to shared data; NULL means no measured launch. */
51 struct tboot *tboot __read_mostly;
52 EXPORT_SYMBOL(tboot);
53
54 /* timeout for APs (in secs) to enter wait-for-SIPI state during shutdown */
55 #define AP_WAIT_TIMEOUT 1
56
57 #undef pr_fmt
58 #define pr_fmt(fmt) "tboot: " fmt
59
60 static u8 tboot_uuid[16] __initdata = TBOOT_UUID;
61
tboot_probe(void)62 void __init tboot_probe(void)
63 {
64 /* Look for valid page-aligned address for shared page. */
65 if (!boot_params.tboot_addr)
66 return;
67 /*
68 * also verify that it is mapped as we expect it before calling
69 * set_fixmap(), to reduce chance of garbage value causing crash
70 */
71 if (!e820_any_mapped(boot_params.tboot_addr,
72 boot_params.tboot_addr, E820_RESERVED)) {
73 pr_warning("non-0 tboot_addr but it is not of type E820_RESERVED\n");
74 return;
75 }
76
77 /* only a natively booted kernel should be using TXT */
78 if (paravirt_enabled()) {
79 pr_warning("non-0 tboot_addr but pv_ops is enabled\n");
80 return;
81 }
82
83 /* Map and check for tboot UUID. */
84 set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
85 tboot = (struct tboot *)fix_to_virt(FIX_TBOOT_BASE);
86 if (memcmp(&tboot_uuid, &tboot->uuid, sizeof(tboot->uuid))) {
87 pr_warning("tboot at 0x%llx is invalid\n",
88 boot_params.tboot_addr);
89 tboot = NULL;
90 return;
91 }
92 if (tboot->version < 5) {
93 pr_warning("tboot version is invalid: %u\n", tboot->version);
94 tboot = NULL;
95 return;
96 }
97
98 pr_info("found shared page at phys addr 0x%llx:\n",
99 boot_params.tboot_addr);
100 pr_debug("version: %d\n", tboot->version);
101 pr_debug("log_addr: 0x%08x\n", tboot->log_addr);
102 pr_debug("shutdown_entry: 0x%x\n", tboot->shutdown_entry);
103 pr_debug("tboot_base: 0x%08x\n", tboot->tboot_base);
104 pr_debug("tboot_size: 0x%x\n", tboot->tboot_size);
105 }
106
107 static pgd_t *tboot_pg_dir;
108 static struct mm_struct tboot_mm = {
109 .mm_rb = RB_ROOT,
110 .pgd = swapper_pg_dir,
111 .mm_users = ATOMIC_INIT(2),
112 .mm_count = ATOMIC_INIT(1),
113 .mmap_sem = __RWSEM_INITIALIZER(init_mm.mmap_sem),
114 .page_table_lock = __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
115 .mmlist = LIST_HEAD_INIT(init_mm.mmlist),
116 };
117
switch_to_tboot_pt(void)118 static inline void switch_to_tboot_pt(void)
119 {
120 write_cr3(virt_to_phys(tboot_pg_dir));
121 }
122
map_tboot_page(unsigned long vaddr,unsigned long pfn,pgprot_t prot)123 static int map_tboot_page(unsigned long vaddr, unsigned long pfn,
124 pgprot_t prot)
125 {
126 pgd_t *pgd;
127 pud_t *pud;
128 pmd_t *pmd;
129 pte_t *pte;
130
131 pgd = pgd_offset(&tboot_mm, vaddr);
132 pud = pud_alloc(&tboot_mm, pgd, vaddr);
133 if (!pud)
134 return -1;
135 pmd = pmd_alloc(&tboot_mm, pud, vaddr);
136 if (!pmd)
137 return -1;
138 pte = pte_alloc_map(&tboot_mm, NULL, pmd, vaddr);
139 if (!pte)
140 return -1;
141 set_pte_at(&tboot_mm, vaddr, pte, pfn_pte(pfn, prot));
142 pte_unmap(pte);
143
144 /*
145 * PTI poisons low addresses in the kernel page tables in the
146 * name of making them unusable for userspace. To execute
147 * code at such a low address, the poison must be cleared.
148 *
149 * Note: 'pgd' actually gets set in pud_alloc().
150 */
151 pgd->pgd &= ~_PAGE_NX;
152
153 return 0;
154 }
155
map_tboot_pages(unsigned long vaddr,unsigned long start_pfn,unsigned long nr)156 static int map_tboot_pages(unsigned long vaddr, unsigned long start_pfn,
157 unsigned long nr)
158 {
159 /* Reuse the original kernel mapping */
160 tboot_pg_dir = pgd_alloc(&tboot_mm);
161 if (!tboot_pg_dir)
162 return -1;
163
164 for (; nr > 0; nr--, vaddr += PAGE_SIZE, start_pfn++) {
165 if (map_tboot_page(vaddr, start_pfn, PAGE_KERNEL_EXEC))
166 return -1;
167 }
168
169 return 0;
170 }
171
tboot_create_trampoline(void)172 static void tboot_create_trampoline(void)
173 {
174 u32 map_base, map_size;
175
176 /* Create identity map for tboot shutdown code. */
177 map_base = PFN_DOWN(tboot->tboot_base);
178 map_size = PFN_UP(tboot->tboot_size);
179 if (map_tboot_pages(map_base << PAGE_SHIFT, map_base, map_size))
180 panic("tboot: Error mapping tboot pages (mfns) @ 0x%x, 0x%x\n",
181 map_base, map_size);
182 }
183
184 #ifdef CONFIG_ACPI_SLEEP
185
add_mac_region(phys_addr_t start,unsigned long size)186 static void add_mac_region(phys_addr_t start, unsigned long size)
187 {
188 struct tboot_mac_region *mr;
189 phys_addr_t end = start + size;
190
191 if (tboot->num_mac_regions >= MAX_TB_MAC_REGIONS)
192 panic("tboot: Too many MAC regions\n");
193
194 if (start && size) {
195 mr = &tboot->mac_regions[tboot->num_mac_regions++];
196 mr->start = round_down(start, PAGE_SIZE);
197 mr->size = round_up(end, PAGE_SIZE) - mr->start;
198 }
199 }
200
tboot_setup_sleep(void)201 static int tboot_setup_sleep(void)
202 {
203 int i;
204
205 tboot->num_mac_regions = 0;
206
207 for (i = 0; i < e820.nr_map; i++) {
208 if ((e820.map[i].type != E820_RAM)
209 && (e820.map[i].type != E820_RESERVED_KERN))
210 continue;
211
212 add_mac_region(e820.map[i].addr, e820.map[i].size);
213 }
214
215 tboot->acpi_sinfo.kernel_s3_resume_vector =
216 real_mode_header->wakeup_start;
217
218 return 0;
219 }
220
221 #else /* no CONFIG_ACPI_SLEEP */
222
tboot_setup_sleep(void)223 static int tboot_setup_sleep(void)
224 {
225 /* S3 shutdown requested, but S3 not supported by the kernel... */
226 BUG();
227 return -1;
228 }
229
230 #endif
231
tboot_shutdown(u32 shutdown_type)232 void tboot_shutdown(u32 shutdown_type)
233 {
234 void (*shutdown)(void);
235
236 if (!tboot_enabled())
237 return;
238
239 /*
240 * if we're being called before the 1:1 mapping is set up then just
241 * return and let the normal shutdown happen; this should only be
242 * due to very early panic()
243 */
244 if (!tboot_pg_dir)
245 return;
246
247 /* if this is S3 then set regions to MAC */
248 if (shutdown_type == TB_SHUTDOWN_S3)
249 if (tboot_setup_sleep())
250 return;
251
252 tboot->shutdown_type = shutdown_type;
253
254 switch_to_tboot_pt();
255
256 shutdown = (void(*)(void))(unsigned long)tboot->shutdown_entry;
257 shutdown();
258
259 /* should not reach here */
260 while (1)
261 halt();
262 }
263
tboot_copy_fadt(const struct acpi_table_fadt * fadt)264 static void tboot_copy_fadt(const struct acpi_table_fadt *fadt)
265 {
266 #define TB_COPY_GAS(tbg, g) \
267 tbg.space_id = g.space_id; \
268 tbg.bit_width = g.bit_width; \
269 tbg.bit_offset = g.bit_offset; \
270 tbg.access_width = g.access_width; \
271 tbg.address = g.address;
272
273 TB_COPY_GAS(tboot->acpi_sinfo.pm1a_cnt_blk, fadt->xpm1a_control_block);
274 TB_COPY_GAS(tboot->acpi_sinfo.pm1b_cnt_blk, fadt->xpm1b_control_block);
275 TB_COPY_GAS(tboot->acpi_sinfo.pm1a_evt_blk, fadt->xpm1a_event_block);
276 TB_COPY_GAS(tboot->acpi_sinfo.pm1b_evt_blk, fadt->xpm1b_event_block);
277
278 /*
279 * We need phys addr of waking vector, but can't use virt_to_phys() on
280 * &acpi_gbl_FACS because it is ioremap'ed, so calc from FACS phys
281 * addr.
282 */
283 tboot->acpi_sinfo.wakeup_vector = fadt->facs +
284 offsetof(struct acpi_table_facs, firmware_waking_vector);
285 }
286
tboot_sleep(u8 sleep_state,u32 pm1a_control,u32 pm1b_control)287 static int tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control)
288 {
289 static u32 acpi_shutdown_map[ACPI_S_STATE_COUNT] = {
290 /* S0,1,2: */ -1, -1, -1,
291 /* S3: */ TB_SHUTDOWN_S3,
292 /* S4: */ TB_SHUTDOWN_S4,
293 /* S5: */ TB_SHUTDOWN_S5 };
294
295 if (!tboot_enabled())
296 return 0;
297
298 tboot_copy_fadt(&acpi_gbl_FADT);
299 tboot->acpi_sinfo.pm1a_cnt_val = pm1a_control;
300 tboot->acpi_sinfo.pm1b_cnt_val = pm1b_control;
301 /* we always use the 32b wakeup vector */
302 tboot->acpi_sinfo.vector_width = 32;
303
304 if (sleep_state >= ACPI_S_STATE_COUNT ||
305 acpi_shutdown_map[sleep_state] == -1) {
306 pr_warning("unsupported sleep state 0x%x\n", sleep_state);
307 return -1;
308 }
309
310 tboot_shutdown(acpi_shutdown_map[sleep_state]);
311 return 0;
312 }
313
tboot_extended_sleep(u8 sleep_state,u32 val_a,u32 val_b)314 static int tboot_extended_sleep(u8 sleep_state, u32 val_a, u32 val_b)
315 {
316 if (!tboot_enabled())
317 return 0;
318
319 pr_warning("tboot is not able to suspend on platforms with reduced hardware sleep (ACPIv5)");
320 return -ENODEV;
321 }
322
323 static atomic_t ap_wfs_count;
324
tboot_wait_for_aps(int num_aps)325 static int tboot_wait_for_aps(int num_aps)
326 {
327 unsigned long timeout;
328
329 timeout = AP_WAIT_TIMEOUT*HZ;
330 while (atomic_read((atomic_t *)&tboot->num_in_wfs) != num_aps &&
331 timeout) {
332 mdelay(1);
333 timeout--;
334 }
335
336 if (timeout)
337 pr_warning("tboot wait for APs timeout\n");
338
339 return !(atomic_read((atomic_t *)&tboot->num_in_wfs) == num_aps);
340 }
341
tboot_cpu_callback(struct notifier_block * nfb,unsigned long action,void * hcpu)342 static int tboot_cpu_callback(struct notifier_block *nfb, unsigned long action,
343 void *hcpu)
344 {
345 switch (action) {
346 case CPU_DYING:
347 atomic_inc(&ap_wfs_count);
348 if (num_online_cpus() == 1)
349 if (tboot_wait_for_aps(atomic_read(&ap_wfs_count)))
350 return NOTIFY_BAD;
351 break;
352 }
353 return NOTIFY_OK;
354 }
355
356 static struct notifier_block tboot_cpu_notifier =
357 {
358 .notifier_call = tboot_cpu_callback,
359 };
360
361 #ifdef CONFIG_DEBUG_FS
362
363 #define TBOOT_LOG_UUID { 0x26, 0x25, 0x19, 0xc0, 0x30, 0x6b, 0xb4, 0x4d, \
364 0x4c, 0x84, 0xa3, 0xe9, 0x53, 0xb8, 0x81, 0x74 }
365
366 #define TBOOT_SERIAL_LOG_ADDR 0x60000
367 #define TBOOT_SERIAL_LOG_SIZE 0x08000
368 #define LOG_MAX_SIZE_OFF 16
369 #define LOG_BUF_OFF 24
370
371 static uint8_t tboot_log_uuid[16] = TBOOT_LOG_UUID;
372
tboot_log_read(struct file * file,char __user * user_buf,size_t count,loff_t * ppos)373 static ssize_t tboot_log_read(struct file *file, char __user *user_buf, size_t count, loff_t *ppos)
374 {
375 void __iomem *log_base;
376 u8 log_uuid[16];
377 u32 max_size;
378 void *kbuf;
379 int ret = -EFAULT;
380
381 log_base = ioremap_nocache(TBOOT_SERIAL_LOG_ADDR, TBOOT_SERIAL_LOG_SIZE);
382 if (!log_base)
383 return ret;
384
385 memcpy_fromio(log_uuid, log_base, sizeof(log_uuid));
386 if (memcmp(&tboot_log_uuid, log_uuid, sizeof(log_uuid)))
387 goto err_iounmap;
388
389 max_size = readl(log_base + LOG_MAX_SIZE_OFF);
390 if (*ppos >= max_size) {
391 ret = 0;
392 goto err_iounmap;
393 }
394
395 if (*ppos + count > max_size)
396 count = max_size - *ppos;
397
398 kbuf = kmalloc(count, GFP_KERNEL);
399 if (!kbuf) {
400 ret = -ENOMEM;
401 goto err_iounmap;
402 }
403
404 memcpy_fromio(kbuf, log_base + LOG_BUF_OFF + *ppos, count);
405 if (copy_to_user(user_buf, kbuf, count))
406 goto err_kfree;
407
408 *ppos += count;
409
410 ret = count;
411
412 err_kfree:
413 kfree(kbuf);
414
415 err_iounmap:
416 iounmap(log_base);
417
418 return ret;
419 }
420
421 static const struct file_operations tboot_log_fops = {
422 .read = tboot_log_read,
423 .llseek = default_llseek,
424 };
425
426 #endif /* CONFIG_DEBUG_FS */
427
tboot_late_init(void)428 static __init int tboot_late_init(void)
429 {
430 if (!tboot_enabled())
431 return 0;
432
433 tboot_create_trampoline();
434
435 atomic_set(&ap_wfs_count, 0);
436 register_hotcpu_notifier(&tboot_cpu_notifier);
437
438 #ifdef CONFIG_DEBUG_FS
439 debugfs_create_file("tboot_log", S_IRUSR,
440 arch_debugfs_dir, NULL, &tboot_log_fops);
441 #endif
442
443 acpi_os_set_prepare_sleep(&tboot_sleep);
444 acpi_os_set_prepare_extended_sleep(&tboot_extended_sleep);
445 return 0;
446 }
447
448 late_initcall(tboot_late_init);
449
450 /*
451 * TXT configuration registers (offsets from TXT_{PUB, PRIV}_CONFIG_REGS_BASE)
452 */
453
454 #define TXT_PUB_CONFIG_REGS_BASE 0xfed30000
455 #define TXT_PRIV_CONFIG_REGS_BASE 0xfed20000
456
457 /* # pages for each config regs space - used by fixmap */
458 #define NR_TXT_CONFIG_PAGES ((TXT_PUB_CONFIG_REGS_BASE - \
459 TXT_PRIV_CONFIG_REGS_BASE) >> PAGE_SHIFT)
460
461 /* offsets from pub/priv config space */
462 #define TXTCR_HEAP_BASE 0x0300
463 #define TXTCR_HEAP_SIZE 0x0308
464
465 #define SHA1_SIZE 20
466
467 struct sha1_hash {
468 u8 hash[SHA1_SIZE];
469 };
470
471 struct sinit_mle_data {
472 u32 version; /* currently 6 */
473 struct sha1_hash bios_acm_id;
474 u32 edx_senter_flags;
475 u64 mseg_valid;
476 struct sha1_hash sinit_hash;
477 struct sha1_hash mle_hash;
478 struct sha1_hash stm_hash;
479 struct sha1_hash lcp_policy_hash;
480 u32 lcp_policy_control;
481 u32 rlp_wakeup_addr;
482 u32 reserved;
483 u32 num_mdrs;
484 u32 mdrs_off;
485 u32 num_vtd_dmars;
486 u32 vtd_dmars_off;
487 } __packed;
488
tboot_get_dmar_table(struct acpi_table_header * dmar_tbl)489 struct acpi_table_header *tboot_get_dmar_table(struct acpi_table_header *dmar_tbl)
490 {
491 void *heap_base, *heap_ptr, *config;
492
493 if (!tboot_enabled())
494 return dmar_tbl;
495
496 /*
497 * ACPI tables may not be DMA protected by tboot, so use DMAR copy
498 * SINIT saved in SinitMleData in TXT heap (which is DMA protected)
499 */
500
501 /* map config space in order to get heap addr */
502 config = ioremap(TXT_PUB_CONFIG_REGS_BASE, NR_TXT_CONFIG_PAGES *
503 PAGE_SIZE);
504 if (!config)
505 return NULL;
506
507 /* now map TXT heap */
508 heap_base = ioremap(*(u64 *)(config + TXTCR_HEAP_BASE),
509 *(u64 *)(config + TXTCR_HEAP_SIZE));
510 iounmap(config);
511 if (!heap_base)
512 return NULL;
513
514 /* walk heap to SinitMleData */
515 /* skip BiosData */
516 heap_ptr = heap_base + *(u64 *)heap_base;
517 /* skip OsMleData */
518 heap_ptr += *(u64 *)heap_ptr;
519 /* skip OsSinitData */
520 heap_ptr += *(u64 *)heap_ptr;
521 /* now points to SinitMleDataSize; set to SinitMleData */
522 heap_ptr += sizeof(u64);
523 /* get addr of DMAR table */
524 dmar_tbl = (struct acpi_table_header *)(heap_ptr +
525 ((struct sinit_mle_data *)heap_ptr)->vtd_dmars_off -
526 sizeof(u64));
527
528 /* don't unmap heap because dmar.c needs access to this */
529
530 return dmar_tbl;
531 }
532
tboot_force_iommu(void)533 int tboot_force_iommu(void)
534 {
535 if (!tboot_enabled())
536 return 0;
537
538 if (no_iommu || swiotlb || dmar_disabled)
539 pr_warning("Forcing Intel-IOMMU to enabled\n");
540
541 dmar_disabled = 0;
542 #ifdef CONFIG_SWIOTLB
543 swiotlb = 0;
544 #endif
545 no_iommu = 0;
546
547 return 1;
548 }
549