1 #define pr_fmt(fmt) "efi: " fmt
2
3 #include <linux/init.h>
4 #include <linux/kernel.h>
5 #include <linux/string.h>
6 #include <linux/time.h>
7 #include <linux/types.h>
8 #include <linux/efi.h>
9 #include <linux/slab.h>
10 #include <linux/memblock.h>
11 #include <linux/bootmem.h>
12 #include <linux/acpi.h>
13 #include <linux/dmi.h>
14
15 #include <asm/e820/api.h>
16 #include <asm/efi.h>
17 #include <asm/uv/uv.h>
18 #include <asm/cpu_device_id.h>
19
20 #define EFI_MIN_RESERVE 5120
21
22 #define EFI_DUMMY_GUID \
23 EFI_GUID(0x4424ac57, 0xbe4b, 0x47dd, 0x9e, 0x97, 0xed, 0x50, 0xf0, 0x9f, 0x92, 0xa9)
24
25 #define QUARK_CSH_SIGNATURE 0x5f435348 /* _CSH */
26 #define QUARK_SECURITY_HEADER_SIZE 0x400
27
28 /*
29 * Header prepended to the standard EFI capsule on Quark systems the are based
30 * on Intel firmware BSP.
31 * @csh_signature: Unique identifier to sanity check signed module
32 * presence ("_CSH").
33 * @version: Current version of CSH used. Should be one for Quark A0.
34 * @modulesize: Size of the entire module including the module header
35 * and payload.
36 * @security_version_number_index: Index of SVN to use for validation of signed
37 * module.
38 * @security_version_number: Used to prevent against roll back of modules.
39 * @rsvd_module_id: Currently unused for Clanton (Quark).
40 * @rsvd_module_vendor: Vendor Identifier. For Intel products value is
41 * 0x00008086.
42 * @rsvd_date: BCD representation of build date as yyyymmdd, where
43 * yyyy=4 digit year, mm=1-12, dd=1-31.
44 * @headersize: Total length of the header including including any
45 * padding optionally added by the signing tool.
46 * @hash_algo: What Hash is used in the module signing.
47 * @cryp_algo: What Crypto is used in the module signing.
48 * @keysize: Total length of the key data including including any
49 * padding optionally added by the signing tool.
50 * @signaturesize: Total length of the signature including including any
51 * padding optionally added by the signing tool.
52 * @rsvd_next_header: 32-bit pointer to the next Secure Boot Module in the
53 * chain, if there is a next header.
54 * @rsvd: Reserved, padding structure to required size.
55 *
56 * See also QuartSecurityHeader_t in
57 * Quark_EDKII_v1.2.1.1/QuarkPlatformPkg/Include/QuarkBootRom.h
58 * from https://downloadcenter.intel.com/download/23197/Intel-Quark-SoC-X1000-Board-Support-Package-BSP
59 */
60 struct quark_security_header {
61 u32 csh_signature;
62 u32 version;
63 u32 modulesize;
64 u32 security_version_number_index;
65 u32 security_version_number;
66 u32 rsvd_module_id;
67 u32 rsvd_module_vendor;
68 u32 rsvd_date;
69 u32 headersize;
70 u32 hash_algo;
71 u32 cryp_algo;
72 u32 keysize;
73 u32 signaturesize;
74 u32 rsvd_next_header;
75 u32 rsvd[2];
76 };
77
78 static efi_char16_t efi_dummy_name[6] = { 'D', 'U', 'M', 'M', 'Y', 0 };
79
80 static bool efi_no_storage_paranoia;
81
82 /*
83 * Some firmware implementations refuse to boot if there's insufficient
84 * space in the variable store. The implementation of garbage collection
85 * in some FW versions causes stale (deleted) variables to take up space
86 * longer than intended and space is only freed once the store becomes
87 * almost completely full.
88 *
89 * Enabling this option disables the space checks in
90 * efi_query_variable_store() and forces garbage collection.
91 *
92 * Only enable this option if deleting EFI variables does not free up
93 * space in your variable store, e.g. if despite deleting variables
94 * you're unable to create new ones.
95 */
setup_storage_paranoia(char * arg)96 static int __init setup_storage_paranoia(char *arg)
97 {
98 efi_no_storage_paranoia = true;
99 return 0;
100 }
101 early_param("efi_no_storage_paranoia", setup_storage_paranoia);
102
103 /*
104 * Deleting the dummy variable which kicks off garbage collection
105 */
efi_delete_dummy_variable(void)106 void efi_delete_dummy_variable(void)
107 {
108 efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
109 EFI_VARIABLE_NON_VOLATILE |
110 EFI_VARIABLE_BOOTSERVICE_ACCESS |
111 EFI_VARIABLE_RUNTIME_ACCESS,
112 0, NULL);
113 }
114
115 /*
116 * In the nonblocking case we do not attempt to perform garbage
117 * collection if we do not have enough free space. Rather, we do the
118 * bare minimum check and give up immediately if the available space
119 * is below EFI_MIN_RESERVE.
120 *
121 * This function is intended to be small and simple because it is
122 * invoked from crash handler paths.
123 */
124 static efi_status_t
query_variable_store_nonblocking(u32 attributes,unsigned long size)125 query_variable_store_nonblocking(u32 attributes, unsigned long size)
126 {
127 efi_status_t status;
128 u64 storage_size, remaining_size, max_size;
129
130 status = efi.query_variable_info_nonblocking(attributes, &storage_size,
131 &remaining_size,
132 &max_size);
133 if (status != EFI_SUCCESS)
134 return status;
135
136 if (remaining_size - size < EFI_MIN_RESERVE)
137 return EFI_OUT_OF_RESOURCES;
138
139 return EFI_SUCCESS;
140 }
141
142 /*
143 * Some firmware implementations refuse to boot if there's insufficient space
144 * in the variable store. Ensure that we never use more than a safe limit.
145 *
146 * Return EFI_SUCCESS if it is safe to write 'size' bytes to the variable
147 * store.
148 */
efi_query_variable_store(u32 attributes,unsigned long size,bool nonblocking)149 efi_status_t efi_query_variable_store(u32 attributes, unsigned long size,
150 bool nonblocking)
151 {
152 efi_status_t status;
153 u64 storage_size, remaining_size, max_size;
154
155 if (!(attributes & EFI_VARIABLE_NON_VOLATILE))
156 return 0;
157
158 if (nonblocking)
159 return query_variable_store_nonblocking(attributes, size);
160
161 status = efi.query_variable_info(attributes, &storage_size,
162 &remaining_size, &max_size);
163 if (status != EFI_SUCCESS)
164 return status;
165
166 /*
167 * We account for that by refusing the write if permitting it would
168 * reduce the available space to under 5KB. This figure was provided by
169 * Samsung, so should be safe.
170 */
171 if ((remaining_size - size < EFI_MIN_RESERVE) &&
172 !efi_no_storage_paranoia) {
173
174 /*
175 * Triggering garbage collection may require that the firmware
176 * generate a real EFI_OUT_OF_RESOURCES error. We can force
177 * that by attempting to use more space than is available.
178 */
179 unsigned long dummy_size = remaining_size + 1024;
180 void *dummy = kzalloc(dummy_size, GFP_ATOMIC);
181
182 if (!dummy)
183 return EFI_OUT_OF_RESOURCES;
184
185 status = efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
186 EFI_VARIABLE_NON_VOLATILE |
187 EFI_VARIABLE_BOOTSERVICE_ACCESS |
188 EFI_VARIABLE_RUNTIME_ACCESS,
189 dummy_size, dummy);
190
191 if (status == EFI_SUCCESS) {
192 /*
193 * This should have failed, so if it didn't make sure
194 * that we delete it...
195 */
196 efi_delete_dummy_variable();
197 }
198
199 kfree(dummy);
200
201 /*
202 * The runtime code may now have triggered a garbage collection
203 * run, so check the variable info again
204 */
205 status = efi.query_variable_info(attributes, &storage_size,
206 &remaining_size, &max_size);
207
208 if (status != EFI_SUCCESS)
209 return status;
210
211 /*
212 * There still isn't enough room, so return an error
213 */
214 if (remaining_size - size < EFI_MIN_RESERVE)
215 return EFI_OUT_OF_RESOURCES;
216 }
217
218 return EFI_SUCCESS;
219 }
220 EXPORT_SYMBOL_GPL(efi_query_variable_store);
221
222 /*
223 * The UEFI specification makes it clear that the operating system is
224 * free to do whatever it wants with boot services code after
225 * ExitBootServices() has been called. Ignoring this recommendation a
226 * significant bunch of EFI implementations continue calling into boot
227 * services code (SetVirtualAddressMap). In order to work around such
228 * buggy implementations we reserve boot services region during EFI
229 * init and make sure it stays executable. Then, after
230 * SetVirtualAddressMap(), it is discarded.
231 *
232 * However, some boot services regions contain data that is required
233 * by drivers, so we need to track which memory ranges can never be
234 * freed. This is done by tagging those regions with the
235 * EFI_MEMORY_RUNTIME attribute.
236 *
237 * Any driver that wants to mark a region as reserved must use
238 * efi_mem_reserve() which will insert a new EFI memory descriptor
239 * into efi.memmap (splitting existing regions if necessary) and tag
240 * it with EFI_MEMORY_RUNTIME.
241 */
efi_arch_mem_reserve(phys_addr_t addr,u64 size)242 void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size)
243 {
244 phys_addr_t new_phys, new_size;
245 struct efi_mem_range mr;
246 efi_memory_desc_t md;
247 int num_entries;
248 void *new;
249
250 if (efi_mem_desc_lookup(addr, &md)) {
251 pr_err("Failed to lookup EFI memory descriptor for %pa\n", &addr);
252 return;
253 }
254
255 if (addr + size > md.phys_addr + (md.num_pages << EFI_PAGE_SHIFT)) {
256 pr_err("Region spans EFI memory descriptors, %pa\n", &addr);
257 return;
258 }
259
260 size += addr % EFI_PAGE_SIZE;
261 size = round_up(size, EFI_PAGE_SIZE);
262 addr = round_down(addr, EFI_PAGE_SIZE);
263
264 mr.range.start = addr;
265 mr.range.end = addr + size - 1;
266 mr.attribute = md.attribute | EFI_MEMORY_RUNTIME;
267
268 num_entries = efi_memmap_split_count(&md, &mr.range);
269 num_entries += efi.memmap.nr_map;
270
271 new_size = efi.memmap.desc_size * num_entries;
272
273 new_phys = efi_memmap_alloc(num_entries);
274 if (!new_phys) {
275 pr_err("Could not allocate boot services memmap\n");
276 return;
277 }
278
279 new = early_memremap(new_phys, new_size);
280 if (!new) {
281 pr_err("Failed to map new boot services memmap\n");
282 return;
283 }
284
285 efi_memmap_insert(&efi.memmap, new, &mr);
286 early_memunmap(new, new_size);
287
288 efi_memmap_install(new_phys, num_entries);
289 e820__range_update(addr, size, E820_TYPE_RAM, E820_TYPE_RESERVED);
290 e820__update_table(e820_table);
291 }
292
293 /*
294 * Helper function for efi_reserve_boot_services() to figure out if we
295 * can free regions in efi_free_boot_services().
296 *
297 * Use this function to ensure we do not free regions owned by somebody
298 * else. We must only reserve (and then free) regions:
299 *
300 * - Not within any part of the kernel
301 * - Not the BIOS reserved area (E820_TYPE_RESERVED, E820_TYPE_NVS, etc)
302 */
can_free_region(u64 start,u64 size)303 static bool can_free_region(u64 start, u64 size)
304 {
305 if (start + size > __pa_symbol(_text) && start <= __pa_symbol(_end))
306 return false;
307
308 if (!e820__mapped_all(start, start+size, E820_TYPE_RAM))
309 return false;
310
311 return true;
312 }
313
efi_reserve_boot_services(void)314 void __init efi_reserve_boot_services(void)
315 {
316 efi_memory_desc_t *md;
317
318 for_each_efi_memory_desc(md) {
319 u64 start = md->phys_addr;
320 u64 size = md->num_pages << EFI_PAGE_SHIFT;
321 bool already_reserved;
322
323 if (md->type != EFI_BOOT_SERVICES_CODE &&
324 md->type != EFI_BOOT_SERVICES_DATA)
325 continue;
326
327 already_reserved = memblock_is_region_reserved(start, size);
328
329 /*
330 * Because the following memblock_reserve() is paired
331 * with free_bootmem_late() for this region in
332 * efi_free_boot_services(), we must be extremely
333 * careful not to reserve, and subsequently free,
334 * critical regions of memory (like the kernel image) or
335 * those regions that somebody else has already
336 * reserved.
337 *
338 * A good example of a critical region that must not be
339 * freed is page zero (first 4Kb of memory), which may
340 * contain boot services code/data but is marked
341 * E820_TYPE_RESERVED by trim_bios_range().
342 */
343 if (!already_reserved) {
344 memblock_reserve(start, size);
345
346 /*
347 * If we are the first to reserve the region, no
348 * one else cares about it. We own it and can
349 * free it later.
350 */
351 if (can_free_region(start, size))
352 continue;
353 }
354
355 /*
356 * We don't own the region. We must not free it.
357 *
358 * Setting this bit for a boot services region really
359 * doesn't make sense as far as the firmware is
360 * concerned, but it does provide us with a way to tag
361 * those regions that must not be paired with
362 * free_bootmem_late().
363 */
364 md->attribute |= EFI_MEMORY_RUNTIME;
365 }
366 }
367
efi_free_boot_services(void)368 void __init efi_free_boot_services(void)
369 {
370 phys_addr_t new_phys, new_size;
371 efi_memory_desc_t *md;
372 int num_entries = 0;
373 void *new, *new_md;
374
375 for_each_efi_memory_desc(md) {
376 unsigned long long start = md->phys_addr;
377 unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
378 size_t rm_size;
379
380 if (md->type != EFI_BOOT_SERVICES_CODE &&
381 md->type != EFI_BOOT_SERVICES_DATA) {
382 num_entries++;
383 continue;
384 }
385
386 /* Do not free, someone else owns it: */
387 if (md->attribute & EFI_MEMORY_RUNTIME) {
388 num_entries++;
389 continue;
390 }
391
392 /*
393 * Nasty quirk: if all sub-1MB memory is used for boot
394 * services, we can get here without having allocated the
395 * real mode trampoline. It's too late to hand boot services
396 * memory back to the memblock allocator, so instead
397 * try to manually allocate the trampoline if needed.
398 *
399 * I've seen this on a Dell XPS 13 9350 with firmware
400 * 1.4.4 with SGX enabled booting Linux via Fedora 24's
401 * grub2-efi on a hard disk. (And no, I don't know why
402 * this happened, but Linux should still try to boot rather
403 * panicing early.)
404 */
405 rm_size = real_mode_size_needed();
406 if (rm_size && (start + rm_size) < (1<<20) && size >= rm_size) {
407 set_real_mode_mem(start, rm_size);
408 start += rm_size;
409 size -= rm_size;
410 }
411
412 free_bootmem_late(start, size);
413 }
414
415 if (!num_entries)
416 return;
417
418 new_size = efi.memmap.desc_size * num_entries;
419 new_phys = efi_memmap_alloc(num_entries);
420 if (!new_phys) {
421 pr_err("Failed to allocate new EFI memmap\n");
422 return;
423 }
424
425 new = memremap(new_phys, new_size, MEMREMAP_WB);
426 if (!new) {
427 pr_err("Failed to map new EFI memmap\n");
428 return;
429 }
430
431 /*
432 * Build a new EFI memmap that excludes any boot services
433 * regions that are not tagged EFI_MEMORY_RUNTIME, since those
434 * regions have now been freed.
435 */
436 new_md = new;
437 for_each_efi_memory_desc(md) {
438 if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
439 (md->type == EFI_BOOT_SERVICES_CODE ||
440 md->type == EFI_BOOT_SERVICES_DATA))
441 continue;
442
443 memcpy(new_md, md, efi.memmap.desc_size);
444 new_md += efi.memmap.desc_size;
445 }
446
447 memunmap(new);
448
449 if (efi_memmap_install(new_phys, num_entries)) {
450 pr_err("Could not install new EFI memmap\n");
451 return;
452 }
453 }
454
455 /*
456 * A number of config table entries get remapped to virtual addresses
457 * after entering EFI virtual mode. However, the kexec kernel requires
458 * their physical addresses therefore we pass them via setup_data and
459 * correct those entries to their respective physical addresses here.
460 *
461 * Currently only handles smbios which is necessary for some firmware
462 * implementation.
463 */
efi_reuse_config(u64 tables,int nr_tables)464 int __init efi_reuse_config(u64 tables, int nr_tables)
465 {
466 int i, sz, ret = 0;
467 void *p, *tablep;
468 struct efi_setup_data *data;
469
470 if (!efi_setup)
471 return 0;
472
473 if (!efi_enabled(EFI_64BIT))
474 return 0;
475
476 data = early_memremap(efi_setup, sizeof(*data));
477 if (!data) {
478 ret = -ENOMEM;
479 goto out;
480 }
481
482 if (!data->smbios)
483 goto out_memremap;
484
485 sz = sizeof(efi_config_table_64_t);
486
487 p = tablep = early_memremap(tables, nr_tables * sz);
488 if (!p) {
489 pr_err("Could not map Configuration table!\n");
490 ret = -ENOMEM;
491 goto out_memremap;
492 }
493
494 for (i = 0; i < efi.systab->nr_tables; i++) {
495 efi_guid_t guid;
496
497 guid = ((efi_config_table_64_t *)p)->guid;
498
499 if (!efi_guidcmp(guid, SMBIOS_TABLE_GUID))
500 ((efi_config_table_64_t *)p)->table = data->smbios;
501 p += sz;
502 }
503 early_memunmap(tablep, nr_tables * sz);
504
505 out_memremap:
506 early_memunmap(data, sizeof(*data));
507 out:
508 return ret;
509 }
510
511 static const struct dmi_system_id sgi_uv1_dmi[] = {
512 { NULL, "SGI UV1",
513 { DMI_MATCH(DMI_PRODUCT_NAME, "Stoutland Platform"),
514 DMI_MATCH(DMI_PRODUCT_VERSION, "1.0"),
515 DMI_MATCH(DMI_BIOS_VENDOR, "SGI.COM"),
516 }
517 },
518 { } /* NULL entry stops DMI scanning */
519 };
520
efi_apply_memmap_quirks(void)521 void __init efi_apply_memmap_quirks(void)
522 {
523 /*
524 * Once setup is done earlier, unmap the EFI memory map on mismatched
525 * firmware/kernel architectures since there is no support for runtime
526 * services.
527 */
528 if (!efi_runtime_supported()) {
529 pr_info("Setup done, disabling due to 32/64-bit mismatch\n");
530 efi_memmap_unmap();
531 }
532
533 /* UV2+ BIOS has a fix for this issue. UV1 still needs the quirk. */
534 if (dmi_check_system(sgi_uv1_dmi))
535 set_bit(EFI_OLD_MEMMAP, &efi.flags);
536 }
537
538 /*
539 * For most modern platforms the preferred method of powering off is via
540 * ACPI. However, there are some that are known to require the use of
541 * EFI runtime services and for which ACPI does not work at all.
542 *
543 * Using EFI is a last resort, to be used only if no other option
544 * exists.
545 */
efi_reboot_required(void)546 bool efi_reboot_required(void)
547 {
548 if (!acpi_gbl_reduced_hardware)
549 return false;
550
551 efi_reboot_quirk_mode = EFI_RESET_WARM;
552 return true;
553 }
554
efi_poweroff_required(void)555 bool efi_poweroff_required(void)
556 {
557 return acpi_gbl_reduced_hardware || acpi_no_s5;
558 }
559
560 #ifdef CONFIG_EFI_CAPSULE_QUIRK_QUARK_CSH
561
qrk_capsule_setup_info(struct capsule_info * cap_info,void ** pkbuff,size_t hdr_bytes)562 static int qrk_capsule_setup_info(struct capsule_info *cap_info, void **pkbuff,
563 size_t hdr_bytes)
564 {
565 struct quark_security_header *csh = *pkbuff;
566
567 /* Only process data block that is larger than the security header */
568 if (hdr_bytes < sizeof(struct quark_security_header))
569 return 0;
570
571 if (csh->csh_signature != QUARK_CSH_SIGNATURE ||
572 csh->headersize != QUARK_SECURITY_HEADER_SIZE)
573 return 1;
574
575 /* Only process data block if EFI header is included */
576 if (hdr_bytes < QUARK_SECURITY_HEADER_SIZE +
577 sizeof(efi_capsule_header_t))
578 return 0;
579
580 pr_debug("Quark security header detected\n");
581
582 if (csh->rsvd_next_header != 0) {
583 pr_err("multiple Quark security headers not supported\n");
584 return -EINVAL;
585 }
586
587 *pkbuff += csh->headersize;
588 cap_info->total_size = csh->headersize;
589
590 /*
591 * Update the first page pointer to skip over the CSH header.
592 */
593 cap_info->phys[0] += csh->headersize;
594
595 /*
596 * cap_info->capsule should point at a virtual mapping of the entire
597 * capsule, starting at the capsule header. Our image has the Quark
598 * security header prepended, so we cannot rely on the default vmap()
599 * mapping created by the generic capsule code.
600 * Given that the Quark firmware does not appear to care about the
601 * virtual mapping, let's just point cap_info->capsule at our copy
602 * of the capsule header.
603 */
604 cap_info->capsule = &cap_info->header;
605
606 return 1;
607 }
608
609 #define ICPU(family, model, quirk_handler) \
610 { X86_VENDOR_INTEL, family, model, X86_FEATURE_ANY, \
611 (unsigned long)&quirk_handler }
612
613 static const struct x86_cpu_id efi_capsule_quirk_ids[] = {
614 ICPU(5, 9, qrk_capsule_setup_info), /* Intel Quark X1000 */
615 { }
616 };
617
efi_capsule_setup_info(struct capsule_info * cap_info,void * kbuff,size_t hdr_bytes)618 int efi_capsule_setup_info(struct capsule_info *cap_info, void *kbuff,
619 size_t hdr_bytes)
620 {
621 int (*quirk_handler)(struct capsule_info *, void **, size_t);
622 const struct x86_cpu_id *id;
623 int ret;
624
625 if (hdr_bytes < sizeof(efi_capsule_header_t))
626 return 0;
627
628 cap_info->total_size = 0;
629
630 id = x86_match_cpu(efi_capsule_quirk_ids);
631 if (id) {
632 /*
633 * The quirk handler is supposed to return
634 * - a value > 0 if the setup should continue, after advancing
635 * kbuff as needed
636 * - 0 if not enough hdr_bytes are available yet
637 * - a negative error code otherwise
638 */
639 quirk_handler = (typeof(quirk_handler))id->driver_data;
640 ret = quirk_handler(cap_info, &kbuff, hdr_bytes);
641 if (ret <= 0)
642 return ret;
643 }
644
645 memcpy(&cap_info->header, kbuff, sizeof(cap_info->header));
646
647 cap_info->total_size += cap_info->header.imagesize;
648
649 return __efi_capsule_setup_info(cap_info);
650 }
651
652 #endif
653