1 // SPDX-License-Identifier: GPL-2.0-only
2 #define pr_fmt(fmt) "efi: " fmt
3
4 #include <linux/init.h>
5 #include <linux/kernel.h>
6 #include <linux/string.h>
7 #include <linux/time.h>
8 #include <linux/types.h>
9 #include <linux/efi.h>
10 #include <linux/slab.h>
11 #include <linux/memblock.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 #include <asm/realmode.h>
20 #include <asm/reboot.h>
21
22 #define EFI_MIN_RESERVE 5120
23
24 #define EFI_DUMMY_GUID \
25 EFI_GUID(0x4424ac57, 0xbe4b, 0x47dd, 0x9e, 0x97, 0xed, 0x50, 0xf0, 0x9f, 0x92, 0xa9)
26
27 #define QUARK_CSH_SIGNATURE 0x5f435348 /* _CSH */
28 #define QUARK_SECURITY_HEADER_SIZE 0x400
29
30 /*
31 * Header prepended to the standard EFI capsule on Quark systems the are based
32 * on Intel firmware BSP.
33 * @csh_signature: Unique identifier to sanity check signed module
34 * presence ("_CSH").
35 * @version: Current version of CSH used. Should be one for Quark A0.
36 * @modulesize: Size of the entire module including the module header
37 * and payload.
38 * @security_version_number_index: Index of SVN to use for validation of signed
39 * module.
40 * @security_version_number: Used to prevent against roll back of modules.
41 * @rsvd_module_id: Currently unused for Clanton (Quark).
42 * @rsvd_module_vendor: Vendor Identifier. For Intel products value is
43 * 0x00008086.
44 * @rsvd_date: BCD representation of build date as yyyymmdd, where
45 * yyyy=4 digit year, mm=1-12, dd=1-31.
46 * @headersize: Total length of the header including including any
47 * padding optionally added by the signing tool.
48 * @hash_algo: What Hash is used in the module signing.
49 * @cryp_algo: What Crypto is used in the module signing.
50 * @keysize: Total length of the key data including including any
51 * padding optionally added by the signing tool.
52 * @signaturesize: Total length of the signature including including any
53 * padding optionally added by the signing tool.
54 * @rsvd_next_header: 32-bit pointer to the next Secure Boot Module in the
55 * chain, if there is a next header.
56 * @rsvd: Reserved, padding structure to required size.
57 *
58 * See also QuartSecurityHeader_t in
59 * Quark_EDKII_v1.2.1.1/QuarkPlatformPkg/Include/QuarkBootRom.h
60 * from https://downloadcenter.intel.com/download/23197/Intel-Quark-SoC-X1000-Board-Support-Package-BSP
61 */
62 struct quark_security_header {
63 u32 csh_signature;
64 u32 version;
65 u32 modulesize;
66 u32 security_version_number_index;
67 u32 security_version_number;
68 u32 rsvd_module_id;
69 u32 rsvd_module_vendor;
70 u32 rsvd_date;
71 u32 headersize;
72 u32 hash_algo;
73 u32 cryp_algo;
74 u32 keysize;
75 u32 signaturesize;
76 u32 rsvd_next_header;
77 u32 rsvd[2];
78 };
79
80 static const efi_char16_t efi_dummy_name[] = L"DUMMY";
81
82 static bool efi_no_storage_paranoia;
83
84 /*
85 * Some firmware implementations refuse to boot if there's insufficient
86 * space in the variable store. The implementation of garbage collection
87 * in some FW versions causes stale (deleted) variables to take up space
88 * longer than intended and space is only freed once the store becomes
89 * almost completely full.
90 *
91 * Enabling this option disables the space checks in
92 * efi_query_variable_store() and forces garbage collection.
93 *
94 * Only enable this option if deleting EFI variables does not free up
95 * space in your variable store, e.g. if despite deleting variables
96 * you're unable to create new ones.
97 */
setup_storage_paranoia(char * arg)98 static int __init setup_storage_paranoia(char *arg)
99 {
100 efi_no_storage_paranoia = true;
101 return 0;
102 }
103 early_param("efi_no_storage_paranoia", setup_storage_paranoia);
104
105 /*
106 * Deleting the dummy variable which kicks off garbage collection
107 */
efi_delete_dummy_variable(void)108 void efi_delete_dummy_variable(void)
109 {
110 efi.set_variable_nonblocking((efi_char16_t *)efi_dummy_name,
111 &EFI_DUMMY_GUID,
112 EFI_VARIABLE_NON_VOLATILE |
113 EFI_VARIABLE_BOOTSERVICE_ACCESS |
114 EFI_VARIABLE_RUNTIME_ACCESS, 0, NULL);
115 }
116
efivar_reserved_space(void)117 u64 efivar_reserved_space(void)
118 {
119 if (efi_no_storage_paranoia)
120 return 0;
121 return EFI_MIN_RESERVE;
122 }
123 EXPORT_SYMBOL_GPL(efivar_reserved_space);
124
125 /*
126 * In the nonblocking case we do not attempt to perform garbage
127 * collection if we do not have enough free space. Rather, we do the
128 * bare minimum check and give up immediately if the available space
129 * is below EFI_MIN_RESERVE.
130 *
131 * This function is intended to be small and simple because it is
132 * invoked from crash handler paths.
133 */
134 static efi_status_t
query_variable_store_nonblocking(u32 attributes,unsigned long size)135 query_variable_store_nonblocking(u32 attributes, unsigned long size)
136 {
137 efi_status_t status;
138 u64 storage_size, remaining_size, max_size;
139
140 status = efi.query_variable_info_nonblocking(attributes, &storage_size,
141 &remaining_size,
142 &max_size);
143 if (status != EFI_SUCCESS)
144 return status;
145
146 if (remaining_size - size < EFI_MIN_RESERVE)
147 return EFI_OUT_OF_RESOURCES;
148
149 return EFI_SUCCESS;
150 }
151
152 /*
153 * Some firmware implementations refuse to boot if there's insufficient space
154 * in the variable store. Ensure that we never use more than a safe limit.
155 *
156 * Return EFI_SUCCESS if it is safe to write 'size' bytes to the variable
157 * store.
158 */
efi_query_variable_store(u32 attributes,unsigned long size,bool nonblocking)159 efi_status_t efi_query_variable_store(u32 attributes, unsigned long size,
160 bool nonblocking)
161 {
162 efi_status_t status;
163 u64 storage_size, remaining_size, max_size;
164
165 if (!(attributes & EFI_VARIABLE_NON_VOLATILE))
166 return 0;
167
168 if (nonblocking)
169 return query_variable_store_nonblocking(attributes, size);
170
171 status = efi.query_variable_info(attributes, &storage_size,
172 &remaining_size, &max_size);
173 if (status != EFI_SUCCESS)
174 return status;
175
176 /*
177 * We account for that by refusing the write if permitting it would
178 * reduce the available space to under 5KB. This figure was provided by
179 * Samsung, so should be safe.
180 */
181 if ((remaining_size - size < EFI_MIN_RESERVE) &&
182 !efi_no_storage_paranoia) {
183
184 /*
185 * Triggering garbage collection may require that the firmware
186 * generate a real EFI_OUT_OF_RESOURCES error. We can force
187 * that by attempting to use more space than is available.
188 */
189 unsigned long dummy_size = remaining_size + 1024;
190 void *dummy = kzalloc(dummy_size, GFP_KERNEL);
191
192 if (!dummy)
193 return EFI_OUT_OF_RESOURCES;
194
195 status = efi.set_variable((efi_char16_t *)efi_dummy_name,
196 &EFI_DUMMY_GUID,
197 EFI_VARIABLE_NON_VOLATILE |
198 EFI_VARIABLE_BOOTSERVICE_ACCESS |
199 EFI_VARIABLE_RUNTIME_ACCESS,
200 dummy_size, dummy);
201
202 if (status == EFI_SUCCESS) {
203 /*
204 * This should have failed, so if it didn't make sure
205 * that we delete it...
206 */
207 efi_delete_dummy_variable();
208 }
209
210 kfree(dummy);
211
212 /*
213 * The runtime code may now have triggered a garbage collection
214 * run, so check the variable info again
215 */
216 status = efi.query_variable_info(attributes, &storage_size,
217 &remaining_size, &max_size);
218
219 if (status != EFI_SUCCESS)
220 return status;
221
222 /*
223 * There still isn't enough room, so return an error
224 */
225 if (remaining_size - size < EFI_MIN_RESERVE)
226 return EFI_OUT_OF_RESOURCES;
227 }
228
229 return EFI_SUCCESS;
230 }
231 EXPORT_SYMBOL_GPL(efi_query_variable_store);
232
233 /*
234 * The UEFI specification makes it clear that the operating system is
235 * free to do whatever it wants with boot services code after
236 * ExitBootServices() has been called. Ignoring this recommendation a
237 * significant bunch of EFI implementations continue calling into boot
238 * services code (SetVirtualAddressMap). In order to work around such
239 * buggy implementations we reserve boot services region during EFI
240 * init and make sure it stays executable. Then, after
241 * SetVirtualAddressMap(), it is discarded.
242 *
243 * However, some boot services regions contain data that is required
244 * by drivers, so we need to track which memory ranges can never be
245 * freed. This is done by tagging those regions with the
246 * EFI_MEMORY_RUNTIME attribute.
247 *
248 * Any driver that wants to mark a region as reserved must use
249 * efi_mem_reserve() which will insert a new EFI memory descriptor
250 * into efi.memmap (splitting existing regions if necessary) and tag
251 * it with EFI_MEMORY_RUNTIME.
252 */
efi_arch_mem_reserve(phys_addr_t addr,u64 size)253 void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size)
254 {
255 struct efi_memory_map_data data = { 0 };
256 struct efi_mem_range mr;
257 efi_memory_desc_t md;
258 int num_entries;
259 void *new;
260
261 if (efi_mem_desc_lookup(addr, &md) ||
262 md.type != EFI_BOOT_SERVICES_DATA) {
263 pr_err("Failed to lookup EFI memory descriptor for %pa\n", &addr);
264 return;
265 }
266
267 if (addr + size > md.phys_addr + (md.num_pages << EFI_PAGE_SHIFT)) {
268 pr_err("Region spans EFI memory descriptors, %pa\n", &addr);
269 return;
270 }
271
272 size += addr % EFI_PAGE_SIZE;
273 size = round_up(size, EFI_PAGE_SIZE);
274 addr = round_down(addr, EFI_PAGE_SIZE);
275
276 mr.range.start = addr;
277 mr.range.end = addr + size - 1;
278 mr.attribute = md.attribute | EFI_MEMORY_RUNTIME;
279
280 num_entries = efi_memmap_split_count(&md, &mr.range);
281 num_entries += efi.memmap.nr_map;
282
283 if (efi_memmap_alloc(num_entries, &data) != 0) {
284 pr_err("Could not allocate boot services memmap\n");
285 return;
286 }
287
288 new = early_memremap_prot(data.phys_map, data.size,
289 pgprot_val(pgprot_encrypted(FIXMAP_PAGE_NORMAL)));
290 if (!new) {
291 pr_err("Failed to map new boot services memmap\n");
292 return;
293 }
294
295 efi_memmap_insert(&efi.memmap, new, &mr);
296 early_memunmap(new, data.size);
297
298 efi_memmap_install(&data);
299 e820__range_update(addr, size, E820_TYPE_RAM, E820_TYPE_RESERVED);
300 e820__update_table(e820_table);
301 }
302
303 /*
304 * Helper function for efi_reserve_boot_services() to figure out if we
305 * can free regions in efi_free_boot_services().
306 *
307 * Use this function to ensure we do not free regions owned by somebody
308 * else. We must only reserve (and then free) regions:
309 *
310 * - Not within any part of the kernel
311 * - Not the BIOS reserved area (E820_TYPE_RESERVED, E820_TYPE_NVS, etc)
312 */
can_free_region(u64 start,u64 size)313 static __init bool can_free_region(u64 start, u64 size)
314 {
315 if (start + size > __pa_symbol(_text) && start <= __pa_symbol(_end))
316 return false;
317
318 if (!e820__mapped_all(start, start+size, E820_TYPE_RAM))
319 return false;
320
321 return true;
322 }
323
efi_reserve_boot_services(void)324 void __init efi_reserve_boot_services(void)
325 {
326 efi_memory_desc_t *md;
327
328 if (!efi_enabled(EFI_MEMMAP))
329 return;
330
331 for_each_efi_memory_desc(md) {
332 u64 start = md->phys_addr;
333 u64 size = md->num_pages << EFI_PAGE_SHIFT;
334 bool already_reserved;
335
336 if (md->type != EFI_BOOT_SERVICES_CODE &&
337 md->type != EFI_BOOT_SERVICES_DATA)
338 continue;
339
340 already_reserved = memblock_is_region_reserved(start, size);
341
342 /*
343 * Because the following memblock_reserve() is paired
344 * with free_reserved_area() for this region in
345 * efi_free_boot_services(), we must be extremely
346 * careful not to reserve, and subsequently free,
347 * critical regions of memory (like the kernel image) or
348 * those regions that somebody else has already
349 * reserved.
350 *
351 * A good example of a critical region that must not be
352 * freed is page zero (first 4Kb of memory), which may
353 * contain boot services code/data but is marked
354 * E820_TYPE_RESERVED by trim_bios_range().
355 */
356 if (!already_reserved) {
357 memblock_reserve(start, size);
358
359 /*
360 * If we are the first to reserve the region, no
361 * one else cares about it. We own it and can
362 * free it later.
363 */
364 if (can_free_region(start, size))
365 continue;
366 }
367
368 /*
369 * We don't own the region. We must not free it.
370 *
371 * Setting this bit for a boot services region really
372 * doesn't make sense as far as the firmware is
373 * concerned, but it does provide us with a way to tag
374 * those regions that must not be paired with
375 * memblock_free_late().
376 */
377 md->attribute |= EFI_MEMORY_RUNTIME;
378 }
379 }
380
381 /*
382 * Apart from having VA mappings for EFI boot services code/data regions,
383 * (duplicate) 1:1 mappings were also created as a quirk for buggy firmware. So,
384 * unmap both 1:1 and VA mappings.
385 */
efi_unmap_pages(efi_memory_desc_t * md)386 static void __init efi_unmap_pages(efi_memory_desc_t *md)
387 {
388 pgd_t *pgd = efi_mm.pgd;
389 u64 pa = md->phys_addr;
390 u64 va = md->virt_addr;
391
392 /*
393 * EFI mixed mode has all RAM mapped to access arguments while making
394 * EFI runtime calls, hence don't unmap EFI boot services code/data
395 * regions.
396 */
397 if (efi_is_mixed())
398 return;
399
400 if (kernel_unmap_pages_in_pgd(pgd, pa, md->num_pages))
401 pr_err("Failed to unmap 1:1 mapping for 0x%llx\n", pa);
402
403 if (kernel_unmap_pages_in_pgd(pgd, va, md->num_pages))
404 pr_err("Failed to unmap VA mapping for 0x%llx\n", va);
405 }
406
407 struct efi_freeable_range {
408 u64 start;
409 u64 end;
410 };
411
412 static struct efi_freeable_range *ranges_to_free;
413
efi_unmap_boot_services(void)414 void __init efi_unmap_boot_services(void)
415 {
416 struct efi_memory_map_data data = { 0 };
417 efi_memory_desc_t *md;
418 int num_entries = 0;
419 int idx = 0;
420 size_t sz;
421 void *new, *new_md;
422
423 /* Keep all regions for /sys/kernel/debug/efi */
424 if (efi_enabled(EFI_DBG))
425 return;
426
427 sz = sizeof(*ranges_to_free) * efi.memmap.nr_map + 1;
428 ranges_to_free = kzalloc(sz, GFP_KERNEL);
429 if (!ranges_to_free) {
430 pr_err("Failed to allocate storage for freeable EFI regions\n");
431 return;
432 }
433
434 for_each_efi_memory_desc(md) {
435 unsigned long long start = md->phys_addr;
436 unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
437 size_t rm_size;
438
439 if (md->type != EFI_BOOT_SERVICES_CODE &&
440 md->type != EFI_BOOT_SERVICES_DATA) {
441 num_entries++;
442 continue;
443 }
444
445 /* Do not free, someone else owns it: */
446 if (md->attribute & EFI_MEMORY_RUNTIME) {
447 num_entries++;
448 continue;
449 }
450
451 /*
452 * Before calling set_virtual_address_map(), EFI boot services
453 * code/data regions were mapped as a quirk for buggy firmware.
454 * Unmap them from efi_pgd before freeing them up.
455 */
456 efi_unmap_pages(md);
457
458 /*
459 * Nasty quirk: if all sub-1MB memory is used for boot
460 * services, we can get here without having allocated the
461 * real mode trampoline. It's too late to hand boot services
462 * memory back to the memblock allocator, so instead
463 * try to manually allocate the trampoline if needed.
464 *
465 * I've seen this on a Dell XPS 13 9350 with firmware
466 * 1.4.4 with SGX enabled booting Linux via Fedora 24's
467 * grub2-efi on a hard disk. (And no, I don't know why
468 * this happened, but Linux should still try to boot rather
469 * panicking early.)
470 */
471 rm_size = real_mode_size_needed();
472 if (rm_size && (start + rm_size) < (1<<20) && size >= rm_size) {
473 set_real_mode_mem(start);
474 start += rm_size;
475 size -= rm_size;
476 }
477
478 /*
479 * Don't free memory under 1M for two reasons:
480 * - BIOS might clobber it
481 * - Crash kernel needs it to be reserved
482 */
483 if (start + size < SZ_1M)
484 continue;
485 if (start < SZ_1M) {
486 size -= (SZ_1M - start);
487 start = SZ_1M;
488 }
489
490 /*
491 * With CONFIG_DEFERRED_STRUCT_PAGE_INIT parts of the memory
492 * map are still not initialized and we can't reliably free
493 * memory here.
494 * Queue the ranges to free at a later point.
495 */
496 ranges_to_free[idx].start = start;
497 ranges_to_free[idx].end = start + size;
498 idx++;
499 }
500
501 if (!num_entries)
502 return;
503
504 if (efi_memmap_alloc(num_entries, &data) != 0) {
505 pr_err("Failed to allocate new EFI memmap\n");
506 return;
507 }
508
509 new = memremap(data.phys_map, data.size, MEMREMAP_WB);
510 if (!new) {
511 pr_err("Failed to map new EFI memmap\n");
512 return;
513 }
514
515 /*
516 * Build a new EFI memmap that excludes any boot services
517 * regions that are not tagged EFI_MEMORY_RUNTIME, since those
518 * regions have now been freed.
519 */
520 new_md = new;
521 for_each_efi_memory_desc(md) {
522 if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
523 (md->type == EFI_BOOT_SERVICES_CODE ||
524 md->type == EFI_BOOT_SERVICES_DATA))
525 continue;
526
527 memcpy(new_md, md, efi.memmap.desc_size);
528 new_md += efi.memmap.desc_size;
529 }
530
531 memunmap(new);
532
533 if (efi_memmap_install(&data) != 0) {
534 pr_err("Could not install new EFI memmap\n");
535 return;
536 }
537 }
538
efi_free_boot_services(void)539 static int __init efi_free_boot_services(void)
540 {
541 struct efi_freeable_range *range = ranges_to_free;
542 unsigned long freed = 0;
543
544 if (!ranges_to_free)
545 return 0;
546
547 while (range->start) {
548 void *start = phys_to_virt(range->start);
549 void *end = phys_to_virt(range->end);
550
551 free_reserved_area(start, end, -1, NULL);
552 freed += (end - start);
553 range++;
554 }
555 kfree(ranges_to_free);
556
557 if (freed)
558 pr_info("Freeing EFI boot services memory: %ldK\n", freed / SZ_1K);
559
560 return 0;
561 }
562 arch_initcall(efi_free_boot_services);
563
564 /*
565 * A number of config table entries get remapped to virtual addresses
566 * after entering EFI virtual mode. However, the kexec kernel requires
567 * their physical addresses therefore we pass them via setup_data and
568 * correct those entries to their respective physical addresses here.
569 *
570 * Currently only handles smbios which is necessary for some firmware
571 * implementation.
572 */
efi_reuse_config(u64 tables,int nr_tables)573 int __init efi_reuse_config(u64 tables, int nr_tables)
574 {
575 int i, sz, ret = 0;
576 void *p, *tablep;
577 struct efi_setup_data *data;
578
579 if (nr_tables == 0)
580 return 0;
581
582 if (!efi_setup)
583 return 0;
584
585 if (!efi_enabled(EFI_64BIT))
586 return 0;
587
588 data = early_memremap(efi_setup, sizeof(*data));
589 if (!data) {
590 ret = -ENOMEM;
591 goto out;
592 }
593
594 if (!data->smbios)
595 goto out_memremap;
596
597 sz = sizeof(efi_config_table_64_t);
598
599 p = tablep = early_memremap(tables, nr_tables * sz);
600 if (!p) {
601 pr_err("Could not map Configuration table!\n");
602 ret = -ENOMEM;
603 goto out_memremap;
604 }
605
606 for (i = 0; i < nr_tables; i++) {
607 efi_guid_t guid;
608
609 guid = ((efi_config_table_64_t *)p)->guid;
610
611 if (!efi_guidcmp(guid, SMBIOS_TABLE_GUID))
612 ((efi_config_table_64_t *)p)->table = data->smbios;
613
614 /* Do not bother to play with mem attr table across kexec */
615 if (!efi_guidcmp(guid, EFI_MEMORY_ATTRIBUTES_TABLE_GUID))
616 ((efi_config_table_64_t *)p)->table = EFI_INVALID_TABLE_ADDR;
617
618 p += sz;
619 }
620 early_memunmap(tablep, nr_tables * sz);
621
622 out_memremap:
623 early_memunmap(data, sizeof(*data));
624 out:
625 return ret;
626 }
627
efi_apply_memmap_quirks(void)628 void __init efi_apply_memmap_quirks(void)
629 {
630 /*
631 * Once setup is done earlier, unmap the EFI memory map on mismatched
632 * firmware/kernel architectures since there is no support for runtime
633 * services.
634 */
635 if (!efi_runtime_supported()) {
636 pr_info("Setup done, disabling due to 32/64-bit mismatch\n");
637 efi_memmap_unmap();
638 }
639 }
640
641 /*
642 * For most modern platforms the preferred method of powering off is via
643 * ACPI. However, there are some that are known to require the use of
644 * EFI runtime services and for which ACPI does not work at all.
645 *
646 * Using EFI is a last resort, to be used only if no other option
647 * exists.
648 */
efi_reboot_required(void)649 bool efi_reboot_required(void)
650 {
651 if (!acpi_gbl_reduced_hardware)
652 return false;
653
654 efi_reboot_quirk_mode = EFI_RESET_WARM;
655 return true;
656 }
657
efi_poweroff_required(void)658 bool efi_poweroff_required(void)
659 {
660 return acpi_gbl_reduced_hardware || acpi_no_s5;
661 }
662
663 #ifdef CONFIG_EFI_CAPSULE_QUIRK_QUARK_CSH
664
qrk_capsule_setup_info(struct capsule_info * cap_info,void ** pkbuff,size_t hdr_bytes)665 static int qrk_capsule_setup_info(struct capsule_info *cap_info, void **pkbuff,
666 size_t hdr_bytes)
667 {
668 struct quark_security_header *csh = *pkbuff;
669
670 /* Only process data block that is larger than the security header */
671 if (hdr_bytes < sizeof(struct quark_security_header))
672 return 0;
673
674 if (csh->csh_signature != QUARK_CSH_SIGNATURE ||
675 csh->headersize != QUARK_SECURITY_HEADER_SIZE)
676 return 1;
677
678 /* Only process data block if EFI header is included */
679 if (hdr_bytes < QUARK_SECURITY_HEADER_SIZE +
680 sizeof(efi_capsule_header_t))
681 return 0;
682
683 pr_debug("Quark security header detected\n");
684
685 if (csh->rsvd_next_header != 0) {
686 pr_err("multiple Quark security headers not supported\n");
687 return -EINVAL;
688 }
689
690 *pkbuff += csh->headersize;
691 cap_info->total_size = csh->headersize;
692
693 /*
694 * Update the first page pointer to skip over the CSH header.
695 */
696 cap_info->phys[0] += csh->headersize;
697
698 /*
699 * cap_info->capsule should point at a virtual mapping of the entire
700 * capsule, starting at the capsule header. Our image has the Quark
701 * security header prepended, so we cannot rely on the default vmap()
702 * mapping created by the generic capsule code.
703 * Given that the Quark firmware does not appear to care about the
704 * virtual mapping, let's just point cap_info->capsule at our copy
705 * of the capsule header.
706 */
707 cap_info->capsule = &cap_info->header;
708
709 return 1;
710 }
711
712 static const struct x86_cpu_id efi_capsule_quirk_ids[] = {
713 X86_MATCH_VFM(INTEL_QUARK_X1000, &qrk_capsule_setup_info),
714 { }
715 };
716
efi_capsule_setup_info(struct capsule_info * cap_info,void * kbuff,size_t hdr_bytes)717 int efi_capsule_setup_info(struct capsule_info *cap_info, void *kbuff,
718 size_t hdr_bytes)
719 {
720 int (*quirk_handler)(struct capsule_info *, void **, size_t);
721 const struct x86_cpu_id *id;
722 int ret;
723
724 if (hdr_bytes < sizeof(efi_capsule_header_t))
725 return 0;
726
727 cap_info->total_size = 0;
728
729 id = x86_match_cpu(efi_capsule_quirk_ids);
730 if (id) {
731 /*
732 * The quirk handler is supposed to return
733 * - a value > 0 if the setup should continue, after advancing
734 * kbuff as needed
735 * - 0 if not enough hdr_bytes are available yet
736 * - a negative error code otherwise
737 */
738 quirk_handler = (typeof(quirk_handler))id->driver_data;
739 ret = quirk_handler(cap_info, &kbuff, hdr_bytes);
740 if (ret <= 0)
741 return ret;
742 }
743
744 memcpy(&cap_info->header, kbuff, sizeof(cap_info->header));
745
746 cap_info->total_size += cap_info->header.imagesize;
747
748 return __efi_capsule_setup_info(cap_info);
749 }
750
751 #endif
752
753 /*
754 * If any access by any efi runtime service causes a page fault, then,
755 * 1. If it's efi_reset_system(), reboot through BIOS.
756 * 2. If any other efi runtime service, then
757 * a. Return error status to the efi caller process.
758 * b. Disable EFI Runtime Services forever and
759 * c. Freeze efi_rts_wq and schedule new process.
760 *
761 * @return: Returns, if the page fault is not handled. This function
762 * will never return if the page fault is handled successfully.
763 */
efi_crash_gracefully_on_page_fault(unsigned long phys_addr)764 void efi_crash_gracefully_on_page_fault(unsigned long phys_addr)
765 {
766 if (!IS_ENABLED(CONFIG_X86_64))
767 return;
768
769 /*
770 * If we get an interrupt/NMI while processing an EFI runtime service
771 * then this is a regular OOPS, not an EFI failure.
772 */
773 if (in_interrupt())
774 return;
775
776 /*
777 * Make sure that an efi runtime service caused the page fault.
778 * READ_ONCE() because we might be OOPSing in a different thread,
779 * and we don't want to trip KTSAN while trying to OOPS.
780 */
781 if (READ_ONCE(efi_rts_work.efi_rts_id) == EFI_NONE ||
782 current_work() != &efi_rts_work.work)
783 return;
784
785 /*
786 * Address range 0x0000 - 0x0fff is always mapped in the efi_pgd, so
787 * page faulting on these addresses isn't expected.
788 */
789 if (phys_addr <= 0x0fff)
790 return;
791
792 /*
793 * Print stack trace as it might be useful to know which EFI Runtime
794 * Service is buggy.
795 */
796 WARN(1, FW_BUG "Page fault caused by firmware at PA: 0x%lx\n",
797 phys_addr);
798
799 /*
800 * Buggy efi_reset_system() is handled differently from other EFI
801 * Runtime Services as it doesn't use efi_rts_wq. Although,
802 * native_machine_emergency_restart() says that machine_real_restart()
803 * could fail, it's better not to complicate this fault handler
804 * because this case occurs *very* rarely and hence could be improved
805 * on a need by basis.
806 */
807 if (efi_rts_work.efi_rts_id == EFI_RESET_SYSTEM) {
808 pr_info("efi_reset_system() buggy! Reboot through BIOS\n");
809 machine_real_restart(MRR_BIOS);
810 return;
811 }
812
813 /*
814 * Before calling EFI Runtime Service, the kernel has switched the
815 * calling process to efi_mm. Hence, switch back to task_mm.
816 */
817 arch_efi_call_virt_teardown();
818
819 /* Signal error status to the efi caller process */
820 efi_rts_work.status = EFI_ABORTED;
821 complete(&efi_rts_work.efi_rts_comp);
822
823 clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
824 pr_info("Froze efi_rts_wq and disabled EFI Runtime Services\n");
825
826 /*
827 * Call schedule() in an infinite loop, so that any spurious wake ups
828 * will never run efi_rts_wq again.
829 */
830 for (;;) {
831 set_current_state(TASK_IDLE);
832 schedule();
833 }
834 }
835