xref: /openbmc/linux/arch/x86/platform/efi/quirks.c (revision d86ff333)
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 memblock_free_late() 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 
efi_free_boot_services(void)407 void __init efi_free_boot_services(void)
408 {
409 	struct efi_memory_map_data data = { 0 };
410 	efi_memory_desc_t *md;
411 	int num_entries = 0;
412 	void *new, *new_md;
413 
414 	/* Keep all regions for /sys/kernel/debug/efi */
415 	if (efi_enabled(EFI_DBG))
416 		return;
417 
418 	for_each_efi_memory_desc(md) {
419 		unsigned long long start = md->phys_addr;
420 		unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
421 		size_t rm_size;
422 
423 		if (md->type != EFI_BOOT_SERVICES_CODE &&
424 		    md->type != EFI_BOOT_SERVICES_DATA) {
425 			num_entries++;
426 			continue;
427 		}
428 
429 		/* Do not free, someone else owns it: */
430 		if (md->attribute & EFI_MEMORY_RUNTIME) {
431 			num_entries++;
432 			continue;
433 		}
434 
435 		/*
436 		 * Before calling set_virtual_address_map(), EFI boot services
437 		 * code/data regions were mapped as a quirk for buggy firmware.
438 		 * Unmap them from efi_pgd before freeing them up.
439 		 */
440 		efi_unmap_pages(md);
441 
442 		/*
443 		 * Nasty quirk: if all sub-1MB memory is used for boot
444 		 * services, we can get here without having allocated the
445 		 * real mode trampoline.  It's too late to hand boot services
446 		 * memory back to the memblock allocator, so instead
447 		 * try to manually allocate the trampoline if needed.
448 		 *
449 		 * I've seen this on a Dell XPS 13 9350 with firmware
450 		 * 1.4.4 with SGX enabled booting Linux via Fedora 24's
451 		 * grub2-efi on a hard disk.  (And no, I don't know why
452 		 * this happened, but Linux should still try to boot rather
453 		 * panicking early.)
454 		 */
455 		rm_size = real_mode_size_needed();
456 		if (rm_size && (start + rm_size) < (1<<20) && size >= rm_size) {
457 			set_real_mode_mem(start);
458 			start += rm_size;
459 			size -= rm_size;
460 		}
461 
462 		/*
463 		 * Don't free memory under 1M for two reasons:
464 		 * - BIOS might clobber it
465 		 * - Crash kernel needs it to be reserved
466 		 */
467 		if (start + size < SZ_1M)
468 			continue;
469 		if (start < SZ_1M) {
470 			size -= (SZ_1M - start);
471 			start = SZ_1M;
472 		}
473 
474 		memblock_free_late(start, size);
475 	}
476 
477 	if (!num_entries)
478 		return;
479 
480 	if (efi_memmap_alloc(num_entries, &data) != 0) {
481 		pr_err("Failed to allocate new EFI memmap\n");
482 		return;
483 	}
484 
485 	new = memremap(data.phys_map, data.size, MEMREMAP_WB);
486 	if (!new) {
487 		pr_err("Failed to map new EFI memmap\n");
488 		return;
489 	}
490 
491 	/*
492 	 * Build a new EFI memmap that excludes any boot services
493 	 * regions that are not tagged EFI_MEMORY_RUNTIME, since those
494 	 * regions have now been freed.
495 	 */
496 	new_md = new;
497 	for_each_efi_memory_desc(md) {
498 		if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
499 		    (md->type == EFI_BOOT_SERVICES_CODE ||
500 		     md->type == EFI_BOOT_SERVICES_DATA))
501 			continue;
502 
503 		memcpy(new_md, md, efi.memmap.desc_size);
504 		new_md += efi.memmap.desc_size;
505 	}
506 
507 	memunmap(new);
508 
509 	if (efi_memmap_install(&data) != 0) {
510 		pr_err("Could not install new EFI memmap\n");
511 		return;
512 	}
513 }
514 
515 /*
516  * A number of config table entries get remapped to virtual addresses
517  * after entering EFI virtual mode. However, the kexec kernel requires
518  * their physical addresses therefore we pass them via setup_data and
519  * correct those entries to their respective physical addresses here.
520  *
521  * Currently only handles smbios which is necessary for some firmware
522  * implementation.
523  */
efi_reuse_config(u64 tables,int nr_tables)524 int __init efi_reuse_config(u64 tables, int nr_tables)
525 {
526 	int i, sz, ret = 0;
527 	void *p, *tablep;
528 	struct efi_setup_data *data;
529 
530 	if (nr_tables == 0)
531 		return 0;
532 
533 	if (!efi_setup)
534 		return 0;
535 
536 	if (!efi_enabled(EFI_64BIT))
537 		return 0;
538 
539 	data = early_memremap(efi_setup, sizeof(*data));
540 	if (!data) {
541 		ret = -ENOMEM;
542 		goto out;
543 	}
544 
545 	if (!data->smbios)
546 		goto out_memremap;
547 
548 	sz = sizeof(efi_config_table_64_t);
549 
550 	p = tablep = early_memremap(tables, nr_tables * sz);
551 	if (!p) {
552 		pr_err("Could not map Configuration table!\n");
553 		ret = -ENOMEM;
554 		goto out_memremap;
555 	}
556 
557 	for (i = 0; i < nr_tables; i++) {
558 		efi_guid_t guid;
559 
560 		guid = ((efi_config_table_64_t *)p)->guid;
561 
562 		if (!efi_guidcmp(guid, SMBIOS_TABLE_GUID))
563 			((efi_config_table_64_t *)p)->table = data->smbios;
564 		p += sz;
565 	}
566 	early_memunmap(tablep, nr_tables * sz);
567 
568 out_memremap:
569 	early_memunmap(data, sizeof(*data));
570 out:
571 	return ret;
572 }
573 
efi_apply_memmap_quirks(void)574 void __init efi_apply_memmap_quirks(void)
575 {
576 	/*
577 	 * Once setup is done earlier, unmap the EFI memory map on mismatched
578 	 * firmware/kernel architectures since there is no support for runtime
579 	 * services.
580 	 */
581 	if (!efi_runtime_supported()) {
582 		pr_info("Setup done, disabling due to 32/64-bit mismatch\n");
583 		efi_memmap_unmap();
584 	}
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 static const struct x86_cpu_id efi_capsule_quirk_ids[] = {
659 	X86_MATCH_VENDOR_FAM_MODEL(INTEL, 5, INTEL_FAM5_QUARK_X1000,
660 				   &qrk_capsule_setup_info),
661 	{ }
662 };
663 
efi_capsule_setup_info(struct capsule_info * cap_info,void * kbuff,size_t hdr_bytes)664 int efi_capsule_setup_info(struct capsule_info *cap_info, void *kbuff,
665 			   size_t hdr_bytes)
666 {
667 	int (*quirk_handler)(struct capsule_info *, void **, size_t);
668 	const struct x86_cpu_id *id;
669 	int ret;
670 
671 	if (hdr_bytes < sizeof(efi_capsule_header_t))
672 		return 0;
673 
674 	cap_info->total_size = 0;
675 
676 	id = x86_match_cpu(efi_capsule_quirk_ids);
677 	if (id) {
678 		/*
679 		 * The quirk handler is supposed to return
680 		 *  - a value > 0 if the setup should continue, after advancing
681 		 *    kbuff as needed
682 		 *  - 0 if not enough hdr_bytes are available yet
683 		 *  - a negative error code otherwise
684 		 */
685 		quirk_handler = (typeof(quirk_handler))id->driver_data;
686 		ret = quirk_handler(cap_info, &kbuff, hdr_bytes);
687 		if (ret <= 0)
688 			return ret;
689 	}
690 
691 	memcpy(&cap_info->header, kbuff, sizeof(cap_info->header));
692 
693 	cap_info->total_size += cap_info->header.imagesize;
694 
695 	return __efi_capsule_setup_info(cap_info);
696 }
697 
698 #endif
699 
700 /*
701  * If any access by any efi runtime service causes a page fault, then,
702  * 1. If it's efi_reset_system(), reboot through BIOS.
703  * 2. If any other efi runtime service, then
704  *    a. Return error status to the efi caller process.
705  *    b. Disable EFI Runtime Services forever and
706  *    c. Freeze efi_rts_wq and schedule new process.
707  *
708  * @return: Returns, if the page fault is not handled. This function
709  * will never return if the page fault is handled successfully.
710  */
efi_crash_gracefully_on_page_fault(unsigned long phys_addr)711 void efi_crash_gracefully_on_page_fault(unsigned long phys_addr)
712 {
713 	if (!IS_ENABLED(CONFIG_X86_64))
714 		return;
715 
716 	/*
717 	 * If we get an interrupt/NMI while processing an EFI runtime service
718 	 * then this is a regular OOPS, not an EFI failure.
719 	 */
720 	if (in_interrupt())
721 		return;
722 
723 	/*
724 	 * Make sure that an efi runtime service caused the page fault.
725 	 * READ_ONCE() because we might be OOPSing in a different thread,
726 	 * and we don't want to trip KTSAN while trying to OOPS.
727 	 */
728 	if (READ_ONCE(efi_rts_work.efi_rts_id) == EFI_NONE ||
729 	    current_work() != &efi_rts_work.work)
730 		return;
731 
732 	/*
733 	 * Address range 0x0000 - 0x0fff is always mapped in the efi_pgd, so
734 	 * page faulting on these addresses isn't expected.
735 	 */
736 	if (phys_addr <= 0x0fff)
737 		return;
738 
739 	/*
740 	 * Print stack trace as it might be useful to know which EFI Runtime
741 	 * Service is buggy.
742 	 */
743 	WARN(1, FW_BUG "Page fault caused by firmware at PA: 0x%lx\n",
744 	     phys_addr);
745 
746 	/*
747 	 * Buggy efi_reset_system() is handled differently from other EFI
748 	 * Runtime Services as it doesn't use efi_rts_wq. Although,
749 	 * native_machine_emergency_restart() says that machine_real_restart()
750 	 * could fail, it's better not to complicate this fault handler
751 	 * because this case occurs *very* rarely and hence could be improved
752 	 * on a need by basis.
753 	 */
754 	if (efi_rts_work.efi_rts_id == EFI_RESET_SYSTEM) {
755 		pr_info("efi_reset_system() buggy! Reboot through BIOS\n");
756 		machine_real_restart(MRR_BIOS);
757 		return;
758 	}
759 
760 	/*
761 	 * Before calling EFI Runtime Service, the kernel has switched the
762 	 * calling process to efi_mm. Hence, switch back to task_mm.
763 	 */
764 	arch_efi_call_virt_teardown();
765 
766 	/* Signal error status to the efi caller process */
767 	efi_rts_work.status = EFI_ABORTED;
768 	complete(&efi_rts_work.efi_rts_comp);
769 
770 	clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
771 	pr_info("Froze efi_rts_wq and disabled EFI Runtime Services\n");
772 
773 	/*
774 	 * Call schedule() in an infinite loop, so that any spurious wake ups
775 	 * will never run efi_rts_wq again.
776 	 */
777 	for (;;) {
778 		set_current_state(TASK_IDLE);
779 		schedule();
780 	}
781 }
782