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 
117 /*
118  * In the nonblocking case we do not attempt to perform garbage
119  * collection if we do not have enough free space. Rather, we do the
120  * bare minimum check and give up immediately if the available space
121  * is below EFI_MIN_RESERVE.
122  *
123  * This function is intended to be small and simple because it is
124  * invoked from crash handler paths.
125  */
126 static efi_status_t
query_variable_store_nonblocking(u32 attributes,unsigned long size)127 query_variable_store_nonblocking(u32 attributes, unsigned long size)
128 {
129 	efi_status_t status;
130 	u64 storage_size, remaining_size, max_size;
131 
132 	status = efi.query_variable_info_nonblocking(attributes, &storage_size,
133 						     &remaining_size,
134 						     &max_size);
135 	if (status != EFI_SUCCESS)
136 		return status;
137 
138 	if (remaining_size - size < EFI_MIN_RESERVE)
139 		return EFI_OUT_OF_RESOURCES;
140 
141 	return EFI_SUCCESS;
142 }
143 
144 /*
145  * Some firmware implementations refuse to boot if there's insufficient space
146  * in the variable store. Ensure that we never use more than a safe limit.
147  *
148  * Return EFI_SUCCESS if it is safe to write 'size' bytes to the variable
149  * store.
150  */
efi_query_variable_store(u32 attributes,unsigned long size,bool nonblocking)151 efi_status_t efi_query_variable_store(u32 attributes, unsigned long size,
152 				      bool nonblocking)
153 {
154 	efi_status_t status;
155 	u64 storage_size, remaining_size, max_size;
156 
157 	if (!(attributes & EFI_VARIABLE_NON_VOLATILE))
158 		return 0;
159 
160 	if (nonblocking)
161 		return query_variable_store_nonblocking(attributes, size);
162 
163 	status = efi.query_variable_info(attributes, &storage_size,
164 					 &remaining_size, &max_size);
165 	if (status != EFI_SUCCESS)
166 		return status;
167 
168 	/*
169 	 * We account for that by refusing the write if permitting it would
170 	 * reduce the available space to under 5KB. This figure was provided by
171 	 * Samsung, so should be safe.
172 	 */
173 	if ((remaining_size - size < EFI_MIN_RESERVE) &&
174 		!efi_no_storage_paranoia) {
175 
176 		/*
177 		 * Triggering garbage collection may require that the firmware
178 		 * generate a real EFI_OUT_OF_RESOURCES error. We can force
179 		 * that by attempting to use more space than is available.
180 		 */
181 		unsigned long dummy_size = remaining_size + 1024;
182 		void *dummy = kzalloc(dummy_size, GFP_KERNEL);
183 
184 		if (!dummy)
185 			return EFI_OUT_OF_RESOURCES;
186 
187 		status = efi.set_variable((efi_char16_t *)efi_dummy_name,
188 					  &EFI_DUMMY_GUID,
189 					  EFI_VARIABLE_NON_VOLATILE |
190 					  EFI_VARIABLE_BOOTSERVICE_ACCESS |
191 					  EFI_VARIABLE_RUNTIME_ACCESS,
192 					  dummy_size, dummy);
193 
194 		if (status == EFI_SUCCESS) {
195 			/*
196 			 * This should have failed, so if it didn't make sure
197 			 * that we delete it...
198 			 */
199 			efi_delete_dummy_variable();
200 		}
201 
202 		kfree(dummy);
203 
204 		/*
205 		 * The runtime code may now have triggered a garbage collection
206 		 * run, so check the variable info again
207 		 */
208 		status = efi.query_variable_info(attributes, &storage_size,
209 						 &remaining_size, &max_size);
210 
211 		if (status != EFI_SUCCESS)
212 			return status;
213 
214 		/*
215 		 * There still isn't enough room, so return an error
216 		 */
217 		if (remaining_size - size < EFI_MIN_RESERVE)
218 			return EFI_OUT_OF_RESOURCES;
219 	}
220 
221 	return EFI_SUCCESS;
222 }
223 EXPORT_SYMBOL_GPL(efi_query_variable_store);
224 
225 /*
226  * The UEFI specification makes it clear that the operating system is
227  * free to do whatever it wants with boot services code after
228  * ExitBootServices() has been called. Ignoring this recommendation a
229  * significant bunch of EFI implementations continue calling into boot
230  * services code (SetVirtualAddressMap). In order to work around such
231  * buggy implementations we reserve boot services region during EFI
232  * init and make sure it stays executable. Then, after
233  * SetVirtualAddressMap(), it is discarded.
234  *
235  * However, some boot services regions contain data that is required
236  * by drivers, so we need to track which memory ranges can never be
237  * freed. This is done by tagging those regions with the
238  * EFI_MEMORY_RUNTIME attribute.
239  *
240  * Any driver that wants to mark a region as reserved must use
241  * efi_mem_reserve() which will insert a new EFI memory descriptor
242  * into efi.memmap (splitting existing regions if necessary) and tag
243  * it with EFI_MEMORY_RUNTIME.
244  */
efi_arch_mem_reserve(phys_addr_t addr,u64 size)245 void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size)
246 {
247 	struct efi_memory_map_data data = { 0 };
248 	struct efi_mem_range mr;
249 	efi_memory_desc_t md;
250 	int num_entries;
251 	void *new;
252 
253 	if (efi_mem_desc_lookup(addr, &md) ||
254 	    md.type != EFI_BOOT_SERVICES_DATA) {
255 		pr_err("Failed to lookup EFI memory descriptor for %pa\n", &addr);
256 		return;
257 	}
258 
259 	if (addr + size > md.phys_addr + (md.num_pages << EFI_PAGE_SHIFT)) {
260 		pr_err("Region spans EFI memory descriptors, %pa\n", &addr);
261 		return;
262 	}
263 
264 	size += addr % EFI_PAGE_SIZE;
265 	size = round_up(size, EFI_PAGE_SIZE);
266 	addr = round_down(addr, EFI_PAGE_SIZE);
267 
268 	mr.range.start = addr;
269 	mr.range.end = addr + size - 1;
270 	mr.attribute = md.attribute | EFI_MEMORY_RUNTIME;
271 
272 	num_entries = efi_memmap_split_count(&md, &mr.range);
273 	num_entries += efi.memmap.nr_map;
274 
275 	if (efi_memmap_alloc(num_entries, &data) != 0) {
276 		pr_err("Could not allocate boot services memmap\n");
277 		return;
278 	}
279 
280 	new = early_memremap_prot(data.phys_map, data.size,
281 				  pgprot_val(pgprot_encrypted(FIXMAP_PAGE_NORMAL)));
282 	if (!new) {
283 		pr_err("Failed to map new boot services memmap\n");
284 		return;
285 	}
286 
287 	efi_memmap_insert(&efi.memmap, new, &mr);
288 	early_memunmap(new, data.size);
289 
290 	efi_memmap_install(&data);
291 	e820__range_update(addr, size, E820_TYPE_RAM, E820_TYPE_RESERVED);
292 	e820__update_table(e820_table);
293 }
294 
295 /*
296  * Helper function for efi_reserve_boot_services() to figure out if we
297  * can free regions in efi_free_boot_services().
298  *
299  * Use this function to ensure we do not free regions owned by somebody
300  * else. We must only reserve (and then free) regions:
301  *
302  * - Not within any part of the kernel
303  * - Not the BIOS reserved area (E820_TYPE_RESERVED, E820_TYPE_NVS, etc)
304  */
can_free_region(u64 start,u64 size)305 static __init bool can_free_region(u64 start, u64 size)
306 {
307 	if (start + size > __pa_symbol(_text) && start <= __pa_symbol(_end))
308 		return false;
309 
310 	if (!e820__mapped_all(start, start+size, E820_TYPE_RAM))
311 		return false;
312 
313 	return true;
314 }
315 
efi_reserve_boot_services(void)316 void __init efi_reserve_boot_services(void)
317 {
318 	efi_memory_desc_t *md;
319 
320 	if (!efi_enabled(EFI_MEMMAP))
321 		return;
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 	 * EFI mixed mode has all RAM mapped to access arguments while making
386 	 * EFI runtime calls, hence don't unmap EFI boot services code/data
387 	 * regions.
388 	 */
389 	if (efi_is_mixed())
390 		return;
391 
392 	if (kernel_unmap_pages_in_pgd(pgd, pa, md->num_pages))
393 		pr_err("Failed to unmap 1:1 mapping for 0x%llx\n", pa);
394 
395 	if (kernel_unmap_pages_in_pgd(pgd, va, md->num_pages))
396 		pr_err("Failed to unmap VA mapping for 0x%llx\n", va);
397 }
398 
efi_free_boot_services(void)399 void __init efi_free_boot_services(void)
400 {
401 	struct efi_memory_map_data data = { 0 };
402 	efi_memory_desc_t *md;
403 	int num_entries = 0;
404 	void *new, *new_md;
405 
406 	/* Keep all regions for /sys/kernel/debug/efi */
407 	if (efi_enabled(EFI_DBG))
408 		return;
409 
410 	for_each_efi_memory_desc(md) {
411 		unsigned long long start = md->phys_addr;
412 		unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
413 		size_t rm_size;
414 
415 		if (md->type != EFI_BOOT_SERVICES_CODE &&
416 		    md->type != EFI_BOOT_SERVICES_DATA) {
417 			num_entries++;
418 			continue;
419 		}
420 
421 		/* Do not free, someone else owns it: */
422 		if (md->attribute & EFI_MEMORY_RUNTIME) {
423 			num_entries++;
424 			continue;
425 		}
426 
427 		/*
428 		 * Before calling set_virtual_address_map(), EFI boot services
429 		 * code/data regions were mapped as a quirk for buggy firmware.
430 		 * Unmap them from efi_pgd before freeing them up.
431 		 */
432 		efi_unmap_pages(md);
433 
434 		/*
435 		 * Nasty quirk: if all sub-1MB memory is used for boot
436 		 * services, we can get here without having allocated the
437 		 * real mode trampoline.  It's too late to hand boot services
438 		 * memory back to the memblock allocator, so instead
439 		 * try to manually allocate the trampoline if needed.
440 		 *
441 		 * I've seen this on a Dell XPS 13 9350 with firmware
442 		 * 1.4.4 with SGX enabled booting Linux via Fedora 24's
443 		 * grub2-efi on a hard disk.  (And no, I don't know why
444 		 * this happened, but Linux should still try to boot rather
445 		 * panicking early.)
446 		 */
447 		rm_size = real_mode_size_needed();
448 		if (rm_size && (start + rm_size) < (1<<20) && size >= rm_size) {
449 			set_real_mode_mem(start);
450 			start += rm_size;
451 			size -= rm_size;
452 		}
453 
454 		/*
455 		 * Don't free memory under 1M for two reasons:
456 		 * - BIOS might clobber it
457 		 * - Crash kernel needs it to be reserved
458 		 */
459 		if (start + size < SZ_1M)
460 			continue;
461 		if (start < SZ_1M) {
462 			size -= (SZ_1M - start);
463 			start = SZ_1M;
464 		}
465 
466 		memblock_free_late(start, size);
467 	}
468 
469 	if (!num_entries)
470 		return;
471 
472 	if (efi_memmap_alloc(num_entries, &data) != 0) {
473 		pr_err("Failed to allocate new EFI memmap\n");
474 		return;
475 	}
476 
477 	new = memremap(data.phys_map, data.size, MEMREMAP_WB);
478 	if (!new) {
479 		pr_err("Failed to map new EFI memmap\n");
480 		return;
481 	}
482 
483 	/*
484 	 * Build a new EFI memmap that excludes any boot services
485 	 * regions that are not tagged EFI_MEMORY_RUNTIME, since those
486 	 * regions have now been freed.
487 	 */
488 	new_md = new;
489 	for_each_efi_memory_desc(md) {
490 		if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
491 		    (md->type == EFI_BOOT_SERVICES_CODE ||
492 		     md->type == EFI_BOOT_SERVICES_DATA))
493 			continue;
494 
495 		memcpy(new_md, md, efi.memmap.desc_size);
496 		new_md += efi.memmap.desc_size;
497 	}
498 
499 	memunmap(new);
500 
501 	if (efi_memmap_install(&data) != 0) {
502 		pr_err("Could not install new EFI memmap\n");
503 		return;
504 	}
505 }
506 
507 /*
508  * A number of config table entries get remapped to virtual addresses
509  * after entering EFI virtual mode. However, the kexec kernel requires
510  * their physical addresses therefore we pass them via setup_data and
511  * correct those entries to their respective physical addresses here.
512  *
513  * Currently only handles smbios which is necessary for some firmware
514  * implementation.
515  */
efi_reuse_config(u64 tables,int nr_tables)516 int __init efi_reuse_config(u64 tables, int nr_tables)
517 {
518 	int i, sz, ret = 0;
519 	void *p, *tablep;
520 	struct efi_setup_data *data;
521 
522 	if (nr_tables == 0)
523 		return 0;
524 
525 	if (!efi_setup)
526 		return 0;
527 
528 	if (!efi_enabled(EFI_64BIT))
529 		return 0;
530 
531 	data = early_memremap(efi_setup, sizeof(*data));
532 	if (!data) {
533 		ret = -ENOMEM;
534 		goto out;
535 	}
536 
537 	if (!data->smbios)
538 		goto out_memremap;
539 
540 	sz = sizeof(efi_config_table_64_t);
541 
542 	p = tablep = early_memremap(tables, nr_tables * sz);
543 	if (!p) {
544 		pr_err("Could not map Configuration table!\n");
545 		ret = -ENOMEM;
546 		goto out_memremap;
547 	}
548 
549 	for (i = 0; i < nr_tables; i++) {
550 		efi_guid_t guid;
551 
552 		guid = ((efi_config_table_64_t *)p)->guid;
553 
554 		if (!efi_guidcmp(guid, SMBIOS_TABLE_GUID))
555 			((efi_config_table_64_t *)p)->table = data->smbios;
556 		p += sz;
557 	}
558 	early_memunmap(tablep, nr_tables * sz);
559 
560 out_memremap:
561 	early_memunmap(data, sizeof(*data));
562 out:
563 	return ret;
564 }
565 
efi_apply_memmap_quirks(void)566 void __init efi_apply_memmap_quirks(void)
567 {
568 	/*
569 	 * Once setup is done earlier, unmap the EFI memory map on mismatched
570 	 * firmware/kernel architectures since there is no support for runtime
571 	 * services.
572 	 */
573 	if (!efi_runtime_supported()) {
574 		pr_info("Setup done, disabling due to 32/64-bit mismatch\n");
575 		efi_memmap_unmap();
576 	}
577 }
578 
579 /*
580  * For most modern platforms the preferred method of powering off is via
581  * ACPI. However, there are some that are known to require the use of
582  * EFI runtime services and for which ACPI does not work at all.
583  *
584  * Using EFI is a last resort, to be used only if no other option
585  * exists.
586  */
efi_reboot_required(void)587 bool efi_reboot_required(void)
588 {
589 	if (!acpi_gbl_reduced_hardware)
590 		return false;
591 
592 	efi_reboot_quirk_mode = EFI_RESET_WARM;
593 	return true;
594 }
595 
efi_poweroff_required(void)596 bool efi_poweroff_required(void)
597 {
598 	return acpi_gbl_reduced_hardware || acpi_no_s5;
599 }
600 
601 #ifdef CONFIG_EFI_CAPSULE_QUIRK_QUARK_CSH
602 
qrk_capsule_setup_info(struct capsule_info * cap_info,void ** pkbuff,size_t hdr_bytes)603 static int qrk_capsule_setup_info(struct capsule_info *cap_info, void **pkbuff,
604 				  size_t hdr_bytes)
605 {
606 	struct quark_security_header *csh = *pkbuff;
607 
608 	/* Only process data block that is larger than the security header */
609 	if (hdr_bytes < sizeof(struct quark_security_header))
610 		return 0;
611 
612 	if (csh->csh_signature != QUARK_CSH_SIGNATURE ||
613 	    csh->headersize != QUARK_SECURITY_HEADER_SIZE)
614 		return 1;
615 
616 	/* Only process data block if EFI header is included */
617 	if (hdr_bytes < QUARK_SECURITY_HEADER_SIZE +
618 			sizeof(efi_capsule_header_t))
619 		return 0;
620 
621 	pr_debug("Quark security header detected\n");
622 
623 	if (csh->rsvd_next_header != 0) {
624 		pr_err("multiple Quark security headers not supported\n");
625 		return -EINVAL;
626 	}
627 
628 	*pkbuff += csh->headersize;
629 	cap_info->total_size = csh->headersize;
630 
631 	/*
632 	 * Update the first page pointer to skip over the CSH header.
633 	 */
634 	cap_info->phys[0] += csh->headersize;
635 
636 	/*
637 	 * cap_info->capsule should point at a virtual mapping of the entire
638 	 * capsule, starting at the capsule header. Our image has the Quark
639 	 * security header prepended, so we cannot rely on the default vmap()
640 	 * mapping created by the generic capsule code.
641 	 * Given that the Quark firmware does not appear to care about the
642 	 * virtual mapping, let's just point cap_info->capsule at our copy
643 	 * of the capsule header.
644 	 */
645 	cap_info->capsule = &cap_info->header;
646 
647 	return 1;
648 }
649 
650 static const struct x86_cpu_id efi_capsule_quirk_ids[] = {
651 	X86_MATCH_VENDOR_FAM_MODEL(INTEL, 5, INTEL_FAM5_QUARK_X1000,
652 				   &qrk_capsule_setup_info),
653 	{ }
654 };
655 
efi_capsule_setup_info(struct capsule_info * cap_info,void * kbuff,size_t hdr_bytes)656 int efi_capsule_setup_info(struct capsule_info *cap_info, void *kbuff,
657 			   size_t hdr_bytes)
658 {
659 	int (*quirk_handler)(struct capsule_info *, void **, size_t);
660 	const struct x86_cpu_id *id;
661 	int ret;
662 
663 	if (hdr_bytes < sizeof(efi_capsule_header_t))
664 		return 0;
665 
666 	cap_info->total_size = 0;
667 
668 	id = x86_match_cpu(efi_capsule_quirk_ids);
669 	if (id) {
670 		/*
671 		 * The quirk handler is supposed to return
672 		 *  - a value > 0 if the setup should continue, after advancing
673 		 *    kbuff as needed
674 		 *  - 0 if not enough hdr_bytes are available yet
675 		 *  - a negative error code otherwise
676 		 */
677 		quirk_handler = (typeof(quirk_handler))id->driver_data;
678 		ret = quirk_handler(cap_info, &kbuff, hdr_bytes);
679 		if (ret <= 0)
680 			return ret;
681 	}
682 
683 	memcpy(&cap_info->header, kbuff, sizeof(cap_info->header));
684 
685 	cap_info->total_size += cap_info->header.imagesize;
686 
687 	return __efi_capsule_setup_info(cap_info);
688 }
689 
690 #endif
691 
692 /*
693  * If any access by any efi runtime service causes a page fault, then,
694  * 1. If it's efi_reset_system(), reboot through BIOS.
695  * 2. If any other efi runtime service, then
696  *    a. Return error status to the efi caller process.
697  *    b. Disable EFI Runtime Services forever and
698  *    c. Freeze efi_rts_wq and schedule new process.
699  *
700  * @return: Returns, if the page fault is not handled. This function
701  * will never return if the page fault is handled successfully.
702  */
efi_crash_gracefully_on_page_fault(unsigned long phys_addr)703 void efi_crash_gracefully_on_page_fault(unsigned long phys_addr)
704 {
705 	if (!IS_ENABLED(CONFIG_X86_64))
706 		return;
707 
708 	/*
709 	 * If we get an interrupt/NMI while processing an EFI runtime service
710 	 * then this is a regular OOPS, not an EFI failure.
711 	 */
712 	if (in_interrupt())
713 		return;
714 
715 	/*
716 	 * Make sure that an efi runtime service caused the page fault.
717 	 * READ_ONCE() because we might be OOPSing in a different thread,
718 	 * and we don't want to trip KTSAN while trying to OOPS.
719 	 */
720 	if (READ_ONCE(efi_rts_work.efi_rts_id) == EFI_NONE ||
721 	    current_work() != &efi_rts_work.work)
722 		return;
723 
724 	/*
725 	 * Address range 0x0000 - 0x0fff is always mapped in the efi_pgd, so
726 	 * page faulting on these addresses isn't expected.
727 	 */
728 	if (phys_addr <= 0x0fff)
729 		return;
730 
731 	/*
732 	 * Print stack trace as it might be useful to know which EFI Runtime
733 	 * Service is buggy.
734 	 */
735 	WARN(1, FW_BUG "Page fault caused by firmware at PA: 0x%lx\n",
736 	     phys_addr);
737 
738 	/*
739 	 * Buggy efi_reset_system() is handled differently from other EFI
740 	 * Runtime Services as it doesn't use efi_rts_wq. Although,
741 	 * native_machine_emergency_restart() says that machine_real_restart()
742 	 * could fail, it's better not to complicate this fault handler
743 	 * because this case occurs *very* rarely and hence could be improved
744 	 * on a need by basis.
745 	 */
746 	if (efi_rts_work.efi_rts_id == EFI_RESET_SYSTEM) {
747 		pr_info("efi_reset_system() buggy! Reboot through BIOS\n");
748 		machine_real_restart(MRR_BIOS);
749 		return;
750 	}
751 
752 	/*
753 	 * Before calling EFI Runtime Service, the kernel has switched the
754 	 * calling process to efi_mm. Hence, switch back to task_mm.
755 	 */
756 	arch_efi_call_virt_teardown();
757 
758 	/* Signal error status to the efi caller process */
759 	efi_rts_work.status = EFI_ABORTED;
760 	complete(&efi_rts_work.efi_rts_comp);
761 
762 	clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
763 	pr_info("Froze efi_rts_wq and disabled EFI Runtime Services\n");
764 
765 	/*
766 	 * Call schedule() in an infinite loop, so that any spurious wake ups
767 	 * will never run efi_rts_wq again.
768 	 */
769 	for (;;) {
770 		set_current_state(TASK_IDLE);
771 		schedule();
772 	}
773 }
774