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/reboot.h>
20
21 #define EFI_MIN_RESERVE 5120
22
23 #define EFI_DUMMY_GUID \
24 EFI_GUID(0x4424ac57, 0xbe4b, 0x47dd, 0x9e, 0x97, 0xed, 0x50, 0xf0, 0x9f, 0x92, 0xa9)
25
26 #define QUARK_CSH_SIGNATURE 0x5f435348 /* _CSH */
27 #define QUARK_SECURITY_HEADER_SIZE 0x400
28
29 /*
30 * Header prepended to the standard EFI capsule on Quark systems the are based
31 * on Intel firmware BSP.
32 * @csh_signature: Unique identifier to sanity check signed module
33 * presence ("_CSH").
34 * @version: Current version of CSH used. Should be one for Quark A0.
35 * @modulesize: Size of the entire module including the module header
36 * and payload.
37 * @security_version_number_index: Index of SVN to use for validation of signed
38 * module.
39 * @security_version_number: Used to prevent against roll back of modules.
40 * @rsvd_module_id: Currently unused for Clanton (Quark).
41 * @rsvd_module_vendor: Vendor Identifier. For Intel products value is
42 * 0x00008086.
43 * @rsvd_date: BCD representation of build date as yyyymmdd, where
44 * yyyy=4 digit year, mm=1-12, dd=1-31.
45 * @headersize: Total length of the header including including any
46 * padding optionally added by the signing tool.
47 * @hash_algo: What Hash is used in the module signing.
48 * @cryp_algo: What Crypto is used in the module signing.
49 * @keysize: Total length of the key data including including any
50 * padding optionally added by the signing tool.
51 * @signaturesize: Total length of the signature including including any
52 * padding optionally added by the signing tool.
53 * @rsvd_next_header: 32-bit pointer to the next Secure Boot Module in the
54 * chain, if there is a next header.
55 * @rsvd: Reserved, padding structure to required size.
56 *
57 * See also QuartSecurityHeader_t in
58 * Quark_EDKII_v1.2.1.1/QuarkPlatformPkg/Include/QuarkBootRom.h
59 * from https://downloadcenter.intel.com/download/23197/Intel-Quark-SoC-X1000-Board-Support-Package-BSP
60 */
61 struct quark_security_header {
62 u32 csh_signature;
63 u32 version;
64 u32 modulesize;
65 u32 security_version_number_index;
66 u32 security_version_number;
67 u32 rsvd_module_id;
68 u32 rsvd_module_vendor;
69 u32 rsvd_date;
70 u32 headersize;
71 u32 hash_algo;
72 u32 cryp_algo;
73 u32 keysize;
74 u32 signaturesize;
75 u32 rsvd_next_header;
76 u32 rsvd[2];
77 };
78
79 static const efi_char16_t efi_dummy_name[] = L"DUMMY";
80
81 static bool efi_no_storage_paranoia;
82
83 /*
84 * Some firmware implementations refuse to boot if there's insufficient
85 * space in the variable store. The implementation of garbage collection
86 * in some FW versions causes stale (deleted) variables to take up space
87 * longer than intended and space is only freed once the store becomes
88 * almost completely full.
89 *
90 * Enabling this option disables the space checks in
91 * efi_query_variable_store() and forces garbage collection.
92 *
93 * Only enable this option if deleting EFI variables does not free up
94 * space in your variable store, e.g. if despite deleting variables
95 * you're unable to create new ones.
96 */
setup_storage_paranoia(char * arg)97 static int __init setup_storage_paranoia(char *arg)
98 {
99 efi_no_storage_paranoia = true;
100 return 0;
101 }
102 early_param("efi_no_storage_paranoia", setup_storage_paranoia);
103
104 /*
105 * Deleting the dummy variable which kicks off garbage collection
106 */
efi_delete_dummy_variable(void)107 void efi_delete_dummy_variable(void)
108 {
109 efi.set_variable_nonblocking((efi_char16_t *)efi_dummy_name,
110 &EFI_DUMMY_GUID,
111 EFI_VARIABLE_NON_VOLATILE |
112 EFI_VARIABLE_BOOTSERVICE_ACCESS |
113 EFI_VARIABLE_RUNTIME_ACCESS, 0, NULL);
114 }
115
116 /*
117 * In the nonblocking case we do not attempt to perform garbage
118 * collection if we do not have enough free space. Rather, we do the
119 * bare minimum check and give up immediately if the available space
120 * is below EFI_MIN_RESERVE.
121 *
122 * This function is intended to be small and simple because it is
123 * invoked from crash handler paths.
124 */
125 static efi_status_t
query_variable_store_nonblocking(u32 attributes,unsigned long size)126 query_variable_store_nonblocking(u32 attributes, unsigned long size)
127 {
128 efi_status_t status;
129 u64 storage_size, remaining_size, max_size;
130
131 status = efi.query_variable_info_nonblocking(attributes, &storage_size,
132 &remaining_size,
133 &max_size);
134 if (status != EFI_SUCCESS)
135 return status;
136
137 if (remaining_size - size < EFI_MIN_RESERVE)
138 return EFI_OUT_OF_RESOURCES;
139
140 return EFI_SUCCESS;
141 }
142
143 /*
144 * Some firmware implementations refuse to boot if there's insufficient space
145 * in the variable store. Ensure that we never use more than a safe limit.
146 *
147 * Return EFI_SUCCESS if it is safe to write 'size' bytes to the variable
148 * store.
149 */
efi_query_variable_store(u32 attributes,unsigned long size,bool nonblocking)150 efi_status_t efi_query_variable_store(u32 attributes, unsigned long size,
151 bool nonblocking)
152 {
153 efi_status_t status;
154 u64 storage_size, remaining_size, max_size;
155
156 if (!(attributes & EFI_VARIABLE_NON_VOLATILE))
157 return 0;
158
159 if (nonblocking)
160 return query_variable_store_nonblocking(attributes, size);
161
162 status = efi.query_variable_info(attributes, &storage_size,
163 &remaining_size, &max_size);
164 if (status != EFI_SUCCESS)
165 return status;
166
167 /*
168 * We account for that by refusing the write if permitting it would
169 * reduce the available space to under 5KB. This figure was provided by
170 * Samsung, so should be safe.
171 */
172 if ((remaining_size - size < EFI_MIN_RESERVE) &&
173 !efi_no_storage_paranoia) {
174
175 /*
176 * Triggering garbage collection may require that the firmware
177 * generate a real EFI_OUT_OF_RESOURCES error. We can force
178 * that by attempting to use more space than is available.
179 */
180 unsigned long dummy_size = remaining_size + 1024;
181 void *dummy = kzalloc(dummy_size, GFP_KERNEL);
182
183 if (!dummy)
184 return EFI_OUT_OF_RESOURCES;
185
186 status = efi.set_variable((efi_char16_t *)efi_dummy_name,
187 &EFI_DUMMY_GUID,
188 EFI_VARIABLE_NON_VOLATILE |
189 EFI_VARIABLE_BOOTSERVICE_ACCESS |
190 EFI_VARIABLE_RUNTIME_ACCESS,
191 dummy_size, dummy);
192
193 if (status == EFI_SUCCESS) {
194 /*
195 * This should have failed, so if it didn't make sure
196 * that we delete it...
197 */
198 efi_delete_dummy_variable();
199 }
200
201 kfree(dummy);
202
203 /*
204 * The runtime code may now have triggered a garbage collection
205 * run, so check the variable info again
206 */
207 status = efi.query_variable_info(attributes, &storage_size,
208 &remaining_size, &max_size);
209
210 if (status != EFI_SUCCESS)
211 return status;
212
213 /*
214 * There still isn't enough room, so return an error
215 */
216 if (remaining_size - size < EFI_MIN_RESERVE)
217 return EFI_OUT_OF_RESOURCES;
218 }
219
220 return EFI_SUCCESS;
221 }
222 EXPORT_SYMBOL_GPL(efi_query_variable_store);
223
224 /*
225 * The UEFI specification makes it clear that the operating system is
226 * free to do whatever it wants with boot services code after
227 * ExitBootServices() has been called. Ignoring this recommendation a
228 * significant bunch of EFI implementations continue calling into boot
229 * services code (SetVirtualAddressMap). In order to work around such
230 * buggy implementations we reserve boot services region during EFI
231 * init and make sure it stays executable. Then, after
232 * SetVirtualAddressMap(), it is discarded.
233 *
234 * However, some boot services regions contain data that is required
235 * by drivers, so we need to track which memory ranges can never be
236 * freed. This is done by tagging those regions with the
237 * EFI_MEMORY_RUNTIME attribute.
238 *
239 * Any driver that wants to mark a region as reserved must use
240 * efi_mem_reserve() which will insert a new EFI memory descriptor
241 * into efi.memmap (splitting existing regions if necessary) and tag
242 * it with EFI_MEMORY_RUNTIME.
243 */
efi_arch_mem_reserve(phys_addr_t addr,u64 size)244 void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size)
245 {
246 phys_addr_t new_phys, new_size;
247 struct efi_mem_range mr;
248 efi_memory_desc_t md;
249 int num_entries;
250 void *new;
251
252 if (efi_mem_desc_lookup(addr, &md) ||
253 md.type != EFI_BOOT_SERVICES_DATA) {
254 pr_err("Failed to lookup EFI memory descriptor for %pa\n", &addr);
255 return;
256 }
257
258 if (addr + size > md.phys_addr + (md.num_pages << EFI_PAGE_SHIFT)) {
259 pr_err("Region spans EFI memory descriptors, %pa\n", &addr);
260 return;
261 }
262
263 /* No need to reserve regions that will never be freed. */
264 if (md.attribute & EFI_MEMORY_RUNTIME)
265 return;
266
267 size += addr % EFI_PAGE_SIZE;
268 size = round_up(size, EFI_PAGE_SIZE);
269 addr = round_down(addr, EFI_PAGE_SIZE);
270
271 mr.range.start = addr;
272 mr.range.end = addr + size - 1;
273 mr.attribute = md.attribute | EFI_MEMORY_RUNTIME;
274
275 num_entries = efi_memmap_split_count(&md, &mr.range);
276 num_entries += efi.memmap.nr_map;
277
278 new_size = efi.memmap.desc_size * num_entries;
279
280 new_phys = efi_memmap_alloc(num_entries);
281 if (!new_phys) {
282 pr_err("Could not allocate boot services memmap\n");
283 return;
284 }
285
286 new = early_memremap(new_phys, new_size);
287 if (!new) {
288 pr_err("Failed to map new boot services memmap\n");
289 return;
290 }
291
292 efi_memmap_insert(&efi.memmap, new, &mr);
293 early_memunmap(new, new_size);
294
295 efi_memmap_install(new_phys, num_entries);
296 }
297
298 /*
299 * Helper function for efi_reserve_boot_services() to figure out if we
300 * can free regions in efi_free_boot_services().
301 *
302 * Use this function to ensure we do not free regions owned by somebody
303 * else. We must only reserve (and then free) regions:
304 *
305 * - Not within any part of the kernel
306 * - Not the BIOS reserved area (E820_TYPE_RESERVED, E820_TYPE_NVS, etc)
307 */
can_free_region(u64 start,u64 size)308 static __init bool can_free_region(u64 start, u64 size)
309 {
310 if (start + size > __pa_symbol(_text) && start <= __pa_symbol(_end))
311 return false;
312
313 if (!e820__mapped_all(start, start+size, E820_TYPE_RAM))
314 return false;
315
316 return true;
317 }
318
efi_reserve_boot_services(void)319 void __init efi_reserve_boot_services(void)
320 {
321 efi_memory_desc_t *md;
322
323 for_each_efi_memory_desc(md) {
324 u64 start = md->phys_addr;
325 u64 size = md->num_pages << EFI_PAGE_SHIFT;
326 bool already_reserved;
327
328 if (md->type != EFI_BOOT_SERVICES_CODE &&
329 md->type != EFI_BOOT_SERVICES_DATA)
330 continue;
331
332 already_reserved = memblock_is_region_reserved(start, size);
333
334 /*
335 * Because the following memblock_reserve() is paired
336 * with memblock_free_late() for this region in
337 * efi_free_boot_services(), we must be extremely
338 * careful not to reserve, and subsequently free,
339 * critical regions of memory (like the kernel image) or
340 * those regions that somebody else has already
341 * reserved.
342 *
343 * A good example of a critical region that must not be
344 * freed is page zero (first 4Kb of memory), which may
345 * contain boot services code/data but is marked
346 * E820_TYPE_RESERVED by trim_bios_range().
347 */
348 if (!already_reserved) {
349 memblock_reserve(start, size);
350
351 /*
352 * If we are the first to reserve the region, no
353 * one else cares about it. We own it and can
354 * free it later.
355 */
356 if (can_free_region(start, size))
357 continue;
358 }
359
360 /*
361 * We don't own the region. We must not free it.
362 *
363 * Setting this bit for a boot services region really
364 * doesn't make sense as far as the firmware is
365 * concerned, but it does provide us with a way to tag
366 * those regions that must not be paired with
367 * memblock_free_late().
368 */
369 md->attribute |= EFI_MEMORY_RUNTIME;
370 }
371 }
372
373 /*
374 * Apart from having VA mappings for EFI boot services code/data regions,
375 * (duplicate) 1:1 mappings were also created as a quirk for buggy firmware. So,
376 * unmap both 1:1 and VA mappings.
377 */
efi_unmap_pages(efi_memory_desc_t * md)378 static void __init efi_unmap_pages(efi_memory_desc_t *md)
379 {
380 pgd_t *pgd = efi_mm.pgd;
381 u64 pa = md->phys_addr;
382 u64 va = md->virt_addr;
383
384 /*
385 * To Do: Remove this check after adding functionality to unmap EFI boot
386 * services code/data regions from direct mapping area because
387 * "efi=old_map" maps EFI regions in swapper_pg_dir.
388 */
389 if (efi_enabled(EFI_OLD_MEMMAP))
390 return;
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_native())
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
efi_free_boot_services(void)407 void __init efi_free_boot_services(void)
408 {
409 phys_addr_t new_phys, new_size;
410 efi_memory_desc_t *md;
411 int num_entries = 0;
412 void *new, *new_md;
413
414 for_each_efi_memory_desc(md) {
415 unsigned long long start = md->phys_addr;
416 unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
417 size_t rm_size;
418
419 if (md->type != EFI_BOOT_SERVICES_CODE &&
420 md->type != EFI_BOOT_SERVICES_DATA) {
421 num_entries++;
422 continue;
423 }
424
425 /* Do not free, someone else owns it: */
426 if (md->attribute & EFI_MEMORY_RUNTIME) {
427 num_entries++;
428 continue;
429 }
430
431 /*
432 * Before calling set_virtual_address_map(), EFI boot services
433 * code/data regions were mapped as a quirk for buggy firmware.
434 * Unmap them from efi_pgd before freeing them up.
435 */
436 efi_unmap_pages(md);
437
438 /*
439 * Nasty quirk: if all sub-1MB memory is used for boot
440 * services, we can get here without having allocated the
441 * real mode trampoline. It's too late to hand boot services
442 * memory back to the memblock allocator, so instead
443 * try to manually allocate the trampoline if needed.
444 *
445 * I've seen this on a Dell XPS 13 9350 with firmware
446 * 1.4.4 with SGX enabled booting Linux via Fedora 24's
447 * grub2-efi on a hard disk. (And no, I don't know why
448 * this happened, but Linux should still try to boot rather
449 * panicing early.)
450 */
451 rm_size = real_mode_size_needed();
452 if (rm_size && (start + rm_size) < (1<<20) && size >= rm_size) {
453 set_real_mode_mem(start);
454 start += rm_size;
455 size -= rm_size;
456 }
457
458 memblock_free_late(start, size);
459 }
460
461 if (!num_entries)
462 return;
463
464 new_size = efi.memmap.desc_size * num_entries;
465 new_phys = efi_memmap_alloc(num_entries);
466 if (!new_phys) {
467 pr_err("Failed to allocate new EFI memmap\n");
468 return;
469 }
470
471 new = memremap(new_phys, new_size, MEMREMAP_WB);
472 if (!new) {
473 pr_err("Failed to map new EFI memmap\n");
474 return;
475 }
476
477 /*
478 * Build a new EFI memmap that excludes any boot services
479 * regions that are not tagged EFI_MEMORY_RUNTIME, since those
480 * regions have now been freed.
481 */
482 new_md = new;
483 for_each_efi_memory_desc(md) {
484 if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
485 (md->type == EFI_BOOT_SERVICES_CODE ||
486 md->type == EFI_BOOT_SERVICES_DATA))
487 continue;
488
489 memcpy(new_md, md, efi.memmap.desc_size);
490 new_md += efi.memmap.desc_size;
491 }
492
493 memunmap(new);
494
495 if (efi_memmap_install(new_phys, num_entries)) {
496 pr_err("Could not install new EFI memmap\n");
497 return;
498 }
499 }
500
501 /*
502 * A number of config table entries get remapped to virtual addresses
503 * after entering EFI virtual mode. However, the kexec kernel requires
504 * their physical addresses therefore we pass them via setup_data and
505 * correct those entries to their respective physical addresses here.
506 *
507 * Currently only handles smbios which is necessary for some firmware
508 * implementation.
509 */
efi_reuse_config(u64 tables,int nr_tables)510 int __init efi_reuse_config(u64 tables, int nr_tables)
511 {
512 int i, sz, ret = 0;
513 void *p, *tablep;
514 struct efi_setup_data *data;
515
516 if (nr_tables == 0)
517 return 0;
518
519 if (!efi_setup)
520 return 0;
521
522 if (!efi_enabled(EFI_64BIT))
523 return 0;
524
525 data = early_memremap(efi_setup, sizeof(*data));
526 if (!data) {
527 ret = -ENOMEM;
528 goto out;
529 }
530
531 if (!data->smbios)
532 goto out_memremap;
533
534 sz = sizeof(efi_config_table_64_t);
535
536 p = tablep = early_memremap(tables, nr_tables * sz);
537 if (!p) {
538 pr_err("Could not map Configuration table!\n");
539 ret = -ENOMEM;
540 goto out_memremap;
541 }
542
543 for (i = 0; i < efi.systab->nr_tables; i++) {
544 efi_guid_t guid;
545
546 guid = ((efi_config_table_64_t *)p)->guid;
547
548 if (!efi_guidcmp(guid, SMBIOS_TABLE_GUID))
549 ((efi_config_table_64_t *)p)->table = data->smbios;
550 p += sz;
551 }
552 early_memunmap(tablep, nr_tables * sz);
553
554 out_memremap:
555 early_memunmap(data, sizeof(*data));
556 out:
557 return ret;
558 }
559
560 static const struct dmi_system_id sgi_uv1_dmi[] = {
561 { NULL, "SGI UV1",
562 { DMI_MATCH(DMI_PRODUCT_NAME, "Stoutland Platform"),
563 DMI_MATCH(DMI_PRODUCT_VERSION, "1.0"),
564 DMI_MATCH(DMI_BIOS_VENDOR, "SGI.COM"),
565 }
566 },
567 { } /* NULL entry stops DMI scanning */
568 };
569
efi_apply_memmap_quirks(void)570 void __init efi_apply_memmap_quirks(void)
571 {
572 /*
573 * Once setup is done earlier, unmap the EFI memory map on mismatched
574 * firmware/kernel architectures since there is no support for runtime
575 * services.
576 */
577 if (!efi_runtime_supported()) {
578 pr_info("Setup done, disabling due to 32/64-bit mismatch\n");
579 efi_memmap_unmap();
580 }
581
582 /* UV2+ BIOS has a fix for this issue. UV1 still needs the quirk. */
583 if (dmi_check_system(sgi_uv1_dmi))
584 set_bit(EFI_OLD_MEMMAP, &efi.flags);
585 }
586
587 /*
588 * For most modern platforms the preferred method of powering off is via
589 * ACPI. However, there are some that are known to require the use of
590 * EFI runtime services and for which ACPI does not work at all.
591 *
592 * Using EFI is a last resort, to be used only if no other option
593 * exists.
594 */
efi_reboot_required(void)595 bool efi_reboot_required(void)
596 {
597 if (!acpi_gbl_reduced_hardware)
598 return false;
599
600 efi_reboot_quirk_mode = EFI_RESET_WARM;
601 return true;
602 }
603
efi_poweroff_required(void)604 bool efi_poweroff_required(void)
605 {
606 return acpi_gbl_reduced_hardware || acpi_no_s5;
607 }
608
609 #ifdef CONFIG_EFI_CAPSULE_QUIRK_QUARK_CSH
610
qrk_capsule_setup_info(struct capsule_info * cap_info,void ** pkbuff,size_t hdr_bytes)611 static int qrk_capsule_setup_info(struct capsule_info *cap_info, void **pkbuff,
612 size_t hdr_bytes)
613 {
614 struct quark_security_header *csh = *pkbuff;
615
616 /* Only process data block that is larger than the security header */
617 if (hdr_bytes < sizeof(struct quark_security_header))
618 return 0;
619
620 if (csh->csh_signature != QUARK_CSH_SIGNATURE ||
621 csh->headersize != QUARK_SECURITY_HEADER_SIZE)
622 return 1;
623
624 /* Only process data block if EFI header is included */
625 if (hdr_bytes < QUARK_SECURITY_HEADER_SIZE +
626 sizeof(efi_capsule_header_t))
627 return 0;
628
629 pr_debug("Quark security header detected\n");
630
631 if (csh->rsvd_next_header != 0) {
632 pr_err("multiple Quark security headers not supported\n");
633 return -EINVAL;
634 }
635
636 *pkbuff += csh->headersize;
637 cap_info->total_size = csh->headersize;
638
639 /*
640 * Update the first page pointer to skip over the CSH header.
641 */
642 cap_info->phys[0] += csh->headersize;
643
644 /*
645 * cap_info->capsule should point at a virtual mapping of the entire
646 * capsule, starting at the capsule header. Our image has the Quark
647 * security header prepended, so we cannot rely on the default vmap()
648 * mapping created by the generic capsule code.
649 * Given that the Quark firmware does not appear to care about the
650 * virtual mapping, let's just point cap_info->capsule at our copy
651 * of the capsule header.
652 */
653 cap_info->capsule = &cap_info->header;
654
655 return 1;
656 }
657
658 #define ICPU(family, model, quirk_handler) \
659 { X86_VENDOR_INTEL, family, model, X86_FEATURE_ANY, \
660 (unsigned long)&quirk_handler }
661
662 static const struct x86_cpu_id efi_capsule_quirk_ids[] = {
663 ICPU(5, 9, qrk_capsule_setup_info), /* Intel Quark X1000 */
664 { }
665 };
666
efi_capsule_setup_info(struct capsule_info * cap_info,void * kbuff,size_t hdr_bytes)667 int efi_capsule_setup_info(struct capsule_info *cap_info, void *kbuff,
668 size_t hdr_bytes)
669 {
670 int (*quirk_handler)(struct capsule_info *, void **, size_t);
671 const struct x86_cpu_id *id;
672 int ret;
673
674 if (hdr_bytes < sizeof(efi_capsule_header_t))
675 return 0;
676
677 cap_info->total_size = 0;
678
679 id = x86_match_cpu(efi_capsule_quirk_ids);
680 if (id) {
681 /*
682 * The quirk handler is supposed to return
683 * - a value > 0 if the setup should continue, after advancing
684 * kbuff as needed
685 * - 0 if not enough hdr_bytes are available yet
686 * - a negative error code otherwise
687 */
688 quirk_handler = (typeof(quirk_handler))id->driver_data;
689 ret = quirk_handler(cap_info, &kbuff, hdr_bytes);
690 if (ret <= 0)
691 return ret;
692 }
693
694 memcpy(&cap_info->header, kbuff, sizeof(cap_info->header));
695
696 cap_info->total_size += cap_info->header.imagesize;
697
698 return __efi_capsule_setup_info(cap_info);
699 }
700
701 #endif
702
703 /*
704 * If any access by any efi runtime service causes a page fault, then,
705 * 1. If it's efi_reset_system(), reboot through BIOS.
706 * 2. If any other efi runtime service, then
707 * a. Return error status to the efi caller process.
708 * b. Disable EFI Runtime Services forever and
709 * c. Freeze efi_rts_wq and schedule new process.
710 *
711 * @return: Returns, if the page fault is not handled. This function
712 * will never return if the page fault is handled successfully.
713 */
efi_recover_from_page_fault(unsigned long phys_addr)714 void efi_recover_from_page_fault(unsigned long phys_addr)
715 {
716 if (!IS_ENABLED(CONFIG_X86_64))
717 return;
718
719 /*
720 * Make sure that an efi runtime service caused the page fault.
721 * "efi_mm" cannot be used to check if the page fault had occurred
722 * in the firmware context because efi=old_map doesn't use efi_pgd.
723 */
724 if (efi_rts_work.efi_rts_id == EFI_NONE)
725 return;
726
727 /*
728 * Address range 0x0000 - 0x0fff is always mapped in the efi_pgd, so
729 * page faulting on these addresses isn't expected.
730 */
731 if (phys_addr <= 0x0fff)
732 return;
733
734 /*
735 * Print stack trace as it might be useful to know which EFI Runtime
736 * Service is buggy.
737 */
738 WARN(1, FW_BUG "Page fault caused by firmware at PA: 0x%lx\n",
739 phys_addr);
740
741 /*
742 * Buggy efi_reset_system() is handled differently from other EFI
743 * Runtime Services as it doesn't use efi_rts_wq. Although,
744 * native_machine_emergency_restart() says that machine_real_restart()
745 * could fail, it's better not to compilcate this fault handler
746 * because this case occurs *very* rarely and hence could be improved
747 * on a need by basis.
748 */
749 if (efi_rts_work.efi_rts_id == EFI_RESET_SYSTEM) {
750 pr_info("efi_reset_system() buggy! Reboot through BIOS\n");
751 machine_real_restart(MRR_BIOS);
752 return;
753 }
754
755 /*
756 * Before calling EFI Runtime Service, the kernel has switched the
757 * calling process to efi_mm. Hence, switch back to task_mm.
758 */
759 arch_efi_call_virt_teardown();
760
761 /* Signal error status to the efi caller process */
762 efi_rts_work.status = EFI_ABORTED;
763 complete(&efi_rts_work.efi_rts_comp);
764
765 clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
766 pr_info("Froze efi_rts_wq and disabled EFI Runtime Services\n");
767
768 /*
769 * Call schedule() in an infinite loop, so that any spurious wake ups
770 * will never run efi_rts_wq again.
771 */
772 for (;;) {
773 set_current_state(TASK_IDLE);
774 schedule();
775 }
776
777 return;
778 }
779
