quirks.c

  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 */
 62struct 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
 80static const efi_char16_t efi_dummy_name[] = L"DUMMY";
 81
 82static 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 */
 98static int __init setup_storage_paranoia(char *arg)
 99{
100	efi_no_storage_paranoia = true;
101	return 0;
102}
103early_param("efi_no_storage_paranoia", setup_storage_paranoia);
104
105/*
106 * Deleting the dummy variable which kicks off garbage collection
107*/
108void 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
117u64 efivar_reserved_space(void)
118{
119	if (efi_no_storage_paranoia)
120		return 0;
121	return EFI_MIN_RESERVE;
122}
123EXPORT_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 */
134static efi_status_t
135query_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 */
159efi_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}
231EXPORT_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 */
253void __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 */
313static __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
324void __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 */
386static 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
407struct efi_freeable_range {
408	u64 start;
409	u64 end;
410};
411
412static struct efi_freeable_range *ranges_to_free;
413
414void __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
539static 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}
562arch_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 */
573int __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
622out_memremap:
623	early_memunmap(data, sizeof(*data));
624out:
625	return ret;
626}
627
628void __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 */
649bool 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
658bool 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
665static 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
712static const struct x86_cpu_id efi_capsule_quirk_ids[] = {
713	X86_MATCH_VFM(INTEL_QUARK_X1000, &qrk_capsule_setup_info),
714	{ }
715};
716
717int 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 */
764void 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}