1 // SPDX-License-Identifier: GPL-2.0-only
2 
3 /* -----------------------------------------------------------------------
4  *
5  *   Copyright 2011 Intel Corporation; author Matt Fleming
6  *
7  * ----------------------------------------------------------------------- */
8 
9 #include <linux/efi.h>
10 #include <linux/pci.h>
11 #include <linux/stddef.h>
12 
13 #include <asm/efi.h>
14 #include <asm/e820/types.h>
15 #include <asm/setup.h>
16 #include <asm/desc.h>
17 #include <asm/boot.h>
18 #include <asm/kaslr.h>
19 #include <asm/sev.h>
20 
21 #include "efistub.h"
22 #include "x86-stub.h"
23 
24 extern char _bss[], _ebss[];
25 
26 const efi_system_table_t *efi_system_table;
27 const efi_dxe_services_table_t *efi_dxe_table;
28 static efi_loaded_image_t *image = NULL;
29 static efi_memory_attribute_protocol_t *memattr;
30 
31 typedef union sev_memory_acceptance_protocol sev_memory_acceptance_protocol_t;
32 union sev_memory_acceptance_protocol {
33 	struct {
34 		efi_status_t (__efiapi * allow_unaccepted_memory)(
35 			sev_memory_acceptance_protocol_t *);
36 	};
37 	struct {
38 		u32 allow_unaccepted_memory;
39 	} mixed_mode;
40 };
41 
42 static efi_status_t
43 preserve_pci_rom_image(efi_pci_io_protocol_t *pci, struct pci_setup_rom **__rom)
44 {
45 	struct pci_setup_rom *rom = NULL;
46 	efi_status_t status;
47 	unsigned long size;
48 	uint64_t romsize;
49 	void *romimage;
50 
51 	/*
52 	 * Some firmware images contain EFI function pointers at the place where
53 	 * the romimage and romsize fields are supposed to be. Typically the EFI
54 	 * code is mapped at high addresses, translating to an unrealistically
55 	 * large romsize. The UEFI spec limits the size of option ROMs to 16
56 	 * MiB so we reject any ROMs over 16 MiB in size to catch this.
57 	 */
58 	romimage = efi_table_attr(pci, romimage);
59 	romsize = efi_table_attr(pci, romsize);
60 	if (!romimage || !romsize || romsize > SZ_16M)
61 		return EFI_INVALID_PARAMETER;
62 
63 	size = romsize + sizeof(*rom);
64 
65 	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
66 			     (void **)&rom);
67 	if (status != EFI_SUCCESS) {
68 		efi_err("Failed to allocate memory for 'rom'\n");
69 		return status;
70 	}
71 
72 	memset(rom, 0, sizeof(*rom));
73 
74 	rom->data.type	= SETUP_PCI;
75 	rom->data.len	= size - sizeof(struct setup_data);
76 	rom->data.next	= 0;
77 	rom->pcilen	= romsize;
78 	*__rom = rom;
79 
80 	status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16,
81 				PCI_VENDOR_ID, 1, &rom->vendor);
82 
83 	if (status != EFI_SUCCESS) {
84 		efi_err("Failed to read rom->vendor\n");
85 		goto free_struct;
86 	}
87 
88 	status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16,
89 				PCI_DEVICE_ID, 1, &rom->devid);
90 
91 	if (status != EFI_SUCCESS) {
92 		efi_err("Failed to read rom->devid\n");
93 		goto free_struct;
94 	}
95 
96 	status = efi_call_proto(pci, get_location, &rom->segment, &rom->bus,
97 				&rom->device, &rom->function);
98 
99 	if (status != EFI_SUCCESS)
100 		goto free_struct;
101 
102 	memcpy(rom->romdata, romimage, romsize);
103 	return status;
104 
105 free_struct:
106 	efi_bs_call(free_pool, rom);
107 	return status;
108 }
109 
110 /*
111  * There's no way to return an informative status from this function,
112  * because any analysis (and printing of error messages) needs to be
113  * done directly at the EFI function call-site.
114  *
115  * For example, EFI_INVALID_PARAMETER could indicate a bug or maybe we
116  * just didn't find any PCI devices, but there's no way to tell outside
117  * the context of the call.
118  */
119 static void setup_efi_pci(struct boot_params *params)
120 {
121 	efi_status_t status;
122 	void **pci_handle = NULL;
123 	efi_guid_t pci_proto = EFI_PCI_IO_PROTOCOL_GUID;
124 	unsigned long size = 0;
125 	struct setup_data *data;
126 	efi_handle_t h;
127 	int i;
128 
129 	status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
130 			     &pci_proto, NULL, &size, pci_handle);
131 
132 	if (status == EFI_BUFFER_TOO_SMALL) {
133 		status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
134 				     (void **)&pci_handle);
135 
136 		if (status != EFI_SUCCESS) {
137 			efi_err("Failed to allocate memory for 'pci_handle'\n");
138 			return;
139 		}
140 
141 		status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
142 				     &pci_proto, NULL, &size, pci_handle);
143 	}
144 
145 	if (status != EFI_SUCCESS)
146 		goto free_handle;
147 
148 	data = (struct setup_data *)(unsigned long)params->hdr.setup_data;
149 
150 	while (data && data->next)
151 		data = (struct setup_data *)(unsigned long)data->next;
152 
153 	for_each_efi_handle(h, pci_handle, size, i) {
154 		efi_pci_io_protocol_t *pci = NULL;
155 		struct pci_setup_rom *rom;
156 
157 		status = efi_bs_call(handle_protocol, h, &pci_proto,
158 				     (void **)&pci);
159 		if (status != EFI_SUCCESS || !pci)
160 			continue;
161 
162 		status = preserve_pci_rom_image(pci, &rom);
163 		if (status != EFI_SUCCESS)
164 			continue;
165 
166 		if (data)
167 			data->next = (unsigned long)rom;
168 		else
169 			params->hdr.setup_data = (unsigned long)rom;
170 
171 		data = (struct setup_data *)rom;
172 	}
173 
174 free_handle:
175 	efi_bs_call(free_pool, pci_handle);
176 }
177 
178 static void retrieve_apple_device_properties(struct boot_params *boot_params)
179 {
180 	efi_guid_t guid = APPLE_PROPERTIES_PROTOCOL_GUID;
181 	struct setup_data *data, *new;
182 	efi_status_t status;
183 	u32 size = 0;
184 	apple_properties_protocol_t *p;
185 
186 	status = efi_bs_call(locate_protocol, &guid, NULL, (void **)&p);
187 	if (status != EFI_SUCCESS)
188 		return;
189 
190 	if (efi_table_attr(p, version) != 0x10000) {
191 		efi_err("Unsupported properties proto version\n");
192 		return;
193 	}
194 
195 	efi_call_proto(p, get_all, NULL, &size);
196 	if (!size)
197 		return;
198 
199 	do {
200 		status = efi_bs_call(allocate_pool, EFI_LOADER_DATA,
201 				     size + sizeof(struct setup_data),
202 				     (void **)&new);
203 		if (status != EFI_SUCCESS) {
204 			efi_err("Failed to allocate memory for 'properties'\n");
205 			return;
206 		}
207 
208 		status = efi_call_proto(p, get_all, new->data, &size);
209 
210 		if (status == EFI_BUFFER_TOO_SMALL)
211 			efi_bs_call(free_pool, new);
212 	} while (status == EFI_BUFFER_TOO_SMALL);
213 
214 	new->type = SETUP_APPLE_PROPERTIES;
215 	new->len  = size;
216 	new->next = 0;
217 
218 	data = (struct setup_data *)(unsigned long)boot_params->hdr.setup_data;
219 	if (!data) {
220 		boot_params->hdr.setup_data = (unsigned long)new;
221 	} else {
222 		while (data->next)
223 			data = (struct setup_data *)(unsigned long)data->next;
224 		data->next = (unsigned long)new;
225 	}
226 }
227 
228 efi_status_t efi_adjust_memory_range_protection(unsigned long start,
229 						unsigned long size)
230 {
231 	efi_status_t status;
232 	efi_gcd_memory_space_desc_t desc;
233 	unsigned long end, next;
234 	unsigned long rounded_start, rounded_end;
235 	unsigned long unprotect_start, unprotect_size;
236 
237 	rounded_start = rounddown(start, EFI_PAGE_SIZE);
238 	rounded_end = roundup(start + size, EFI_PAGE_SIZE);
239 
240 	if (memattr != NULL) {
241 		status = efi_call_proto(memattr, set_memory_attributes,
242 					rounded_start,
243 					rounded_end - rounded_start,
244 					EFI_MEMORY_RO);
245 		if (status != EFI_SUCCESS) {
246 			efi_warn("Failed to set EFI_MEMORY_RO attribute\n");
247 			return status;
248 		}
249 
250 		status = efi_call_proto(memattr, clear_memory_attributes,
251 					rounded_start,
252 					rounded_end - rounded_start,
253 					EFI_MEMORY_XP);
254 		if (status != EFI_SUCCESS)
255 			efi_warn("Failed to clear EFI_MEMORY_XP attribute\n");
256 		return status;
257 	}
258 
259 	if (efi_dxe_table == NULL)
260 		return EFI_SUCCESS;
261 
262 	/*
263 	 * Don't modify memory region attributes, they are
264 	 * already suitable, to lower the possibility to
265 	 * encounter firmware bugs.
266 	 */
267 
268 	for (end = start + size; start < end; start = next) {
269 
270 		status = efi_dxe_call(get_memory_space_descriptor, start, &desc);
271 
272 		if (status != EFI_SUCCESS)
273 			break;
274 
275 		next = desc.base_address + desc.length;
276 
277 		/*
278 		 * Only system memory is suitable for trampoline/kernel image placement,
279 		 * so only this type of memory needs its attributes to be modified.
280 		 */
281 
282 		if (desc.gcd_memory_type != EfiGcdMemoryTypeSystemMemory ||
283 		    (desc.attributes & (EFI_MEMORY_RO | EFI_MEMORY_XP)) == 0)
284 			continue;
285 
286 		unprotect_start = max(rounded_start, (unsigned long)desc.base_address);
287 		unprotect_size = min(rounded_end, next) - unprotect_start;
288 
289 		status = efi_dxe_call(set_memory_space_attributes,
290 				      unprotect_start, unprotect_size,
291 				      EFI_MEMORY_WB);
292 
293 		if (status != EFI_SUCCESS) {
294 			efi_warn("Unable to unprotect memory range [%08lx,%08lx]: %lx\n",
295 				 unprotect_start,
296 				 unprotect_start + unprotect_size,
297 				 status);
298 			break;
299 		}
300 	}
301 	return EFI_SUCCESS;
302 }
303 
304 static void setup_unaccepted_memory(void)
305 {
306 	efi_guid_t mem_acceptance_proto = OVMF_SEV_MEMORY_ACCEPTANCE_PROTOCOL_GUID;
307 	sev_memory_acceptance_protocol_t *proto;
308 	efi_status_t status;
309 
310 	if (!IS_ENABLED(CONFIG_UNACCEPTED_MEMORY))
311 		return;
312 
313 	/*
314 	 * Enable unaccepted memory before calling exit boot services in order
315 	 * for the UEFI to not accept all memory on EBS.
316 	 */
317 	status = efi_bs_call(locate_protocol, &mem_acceptance_proto, NULL,
318 			     (void **)&proto);
319 	if (status != EFI_SUCCESS)
320 		return;
321 
322 	status = efi_call_proto(proto, allow_unaccepted_memory);
323 	if (status != EFI_SUCCESS)
324 		efi_err("Memory acceptance protocol failed\n");
325 }
326 
327 static efi_char16_t *efistub_fw_vendor(void)
328 {
329 	unsigned long vendor = efi_table_attr(efi_system_table, fw_vendor);
330 
331 	return (efi_char16_t *)vendor;
332 }
333 
334 static const efi_char16_t apple[] = L"Apple";
335 
336 static void setup_quirks(struct boot_params *boot_params)
337 {
338 	if (IS_ENABLED(CONFIG_APPLE_PROPERTIES) &&
339 	    !memcmp(efistub_fw_vendor(), apple, sizeof(apple)))
340 		retrieve_apple_device_properties(boot_params);
341 }
342 
343 /*
344  * See if we have Universal Graphics Adapter (UGA) protocol
345  */
346 static efi_status_t
347 setup_uga(struct screen_info *si, efi_guid_t *uga_proto, unsigned long size)
348 {
349 	efi_status_t status;
350 	u32 width, height;
351 	void **uga_handle = NULL;
352 	efi_uga_draw_protocol_t *uga = NULL, *first_uga;
353 	efi_handle_t handle;
354 	int i;
355 
356 	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
357 			     (void **)&uga_handle);
358 	if (status != EFI_SUCCESS)
359 		return status;
360 
361 	status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
362 			     uga_proto, NULL, &size, uga_handle);
363 	if (status != EFI_SUCCESS)
364 		goto free_handle;
365 
366 	height = 0;
367 	width = 0;
368 
369 	first_uga = NULL;
370 	for_each_efi_handle(handle, uga_handle, size, i) {
371 		efi_guid_t pciio_proto = EFI_PCI_IO_PROTOCOL_GUID;
372 		u32 w, h, depth, refresh;
373 		void *pciio;
374 
375 		status = efi_bs_call(handle_protocol, handle, uga_proto,
376 				     (void **)&uga);
377 		if (status != EFI_SUCCESS)
378 			continue;
379 
380 		pciio = NULL;
381 		efi_bs_call(handle_protocol, handle, &pciio_proto, &pciio);
382 
383 		status = efi_call_proto(uga, get_mode, &w, &h, &depth, &refresh);
384 		if (status == EFI_SUCCESS && (!first_uga || pciio)) {
385 			width = w;
386 			height = h;
387 
388 			/*
389 			 * Once we've found a UGA supporting PCIIO,
390 			 * don't bother looking any further.
391 			 */
392 			if (pciio)
393 				break;
394 
395 			first_uga = uga;
396 		}
397 	}
398 
399 	if (!width && !height)
400 		goto free_handle;
401 
402 	/* EFI framebuffer */
403 	si->orig_video_isVGA	= VIDEO_TYPE_EFI;
404 
405 	si->lfb_depth		= 32;
406 	si->lfb_width		= width;
407 	si->lfb_height		= height;
408 
409 	si->red_size		= 8;
410 	si->red_pos		= 16;
411 	si->green_size		= 8;
412 	si->green_pos		= 8;
413 	si->blue_size		= 8;
414 	si->blue_pos		= 0;
415 	si->rsvd_size		= 8;
416 	si->rsvd_pos		= 24;
417 
418 free_handle:
419 	efi_bs_call(free_pool, uga_handle);
420 
421 	return status;
422 }
423 
424 static void setup_graphics(struct boot_params *boot_params)
425 {
426 	efi_guid_t graphics_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
427 	struct screen_info *si;
428 	efi_guid_t uga_proto = EFI_UGA_PROTOCOL_GUID;
429 	efi_status_t status;
430 	unsigned long size;
431 	void **gop_handle = NULL;
432 	void **uga_handle = NULL;
433 
434 	si = &boot_params->screen_info;
435 	memset(si, 0, sizeof(*si));
436 
437 	size = 0;
438 	status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
439 			     &graphics_proto, NULL, &size, gop_handle);
440 	if (status == EFI_BUFFER_TOO_SMALL)
441 		status = efi_setup_gop(si, &graphics_proto, size);
442 
443 	if (status != EFI_SUCCESS) {
444 		size = 0;
445 		status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
446 				     &uga_proto, NULL, &size, uga_handle);
447 		if (status == EFI_BUFFER_TOO_SMALL)
448 			setup_uga(si, &uga_proto, size);
449 	}
450 }
451 
452 
453 static void __noreturn efi_exit(efi_handle_t handle, efi_status_t status)
454 {
455 	efi_bs_call(exit, handle, status, 0, NULL);
456 	for(;;)
457 		asm("hlt");
458 }
459 
460 void __noreturn efi_stub_entry(efi_handle_t handle,
461 			       efi_system_table_t *sys_table_arg,
462 			       struct boot_params *boot_params);
463 
464 /*
465  * Because the x86 boot code expects to be passed a boot_params we
466  * need to create one ourselves (usually the bootloader would create
467  * one for us).
468  */
469 efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
470 				   efi_system_table_t *sys_table_arg)
471 {
472 	static struct boot_params boot_params __page_aligned_bss;
473 	struct setup_header *hdr = &boot_params.hdr;
474 	efi_guid_t proto = LOADED_IMAGE_PROTOCOL_GUID;
475 	int options_size = 0;
476 	efi_status_t status;
477 	char *cmdline_ptr;
478 
479 	if (efi_is_native())
480 		memset(_bss, 0, _ebss - _bss);
481 
482 	efi_system_table = sys_table_arg;
483 
484 	/* Check if we were booted by the EFI firmware */
485 	if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
486 		efi_exit(handle, EFI_INVALID_PARAMETER);
487 
488 	status = efi_bs_call(handle_protocol, handle, &proto, (void **)&image);
489 	if (status != EFI_SUCCESS) {
490 		efi_err("Failed to get handle for LOADED_IMAGE_PROTOCOL\n");
491 		efi_exit(handle, status);
492 	}
493 
494 	/* Assign the setup_header fields that the kernel actually cares about */
495 	hdr->root_flags	= 1;
496 	hdr->vid_mode	= 0xffff;
497 
498 	hdr->type_of_loader = 0x21;
499 	hdr->initrd_addr_max = INT_MAX;
500 
501 	/* Convert unicode cmdline to ascii */
502 	cmdline_ptr = efi_convert_cmdline(image, &options_size);
503 	if (!cmdline_ptr)
504 		goto fail;
505 
506 	efi_set_u64_split((unsigned long)cmdline_ptr, &hdr->cmd_line_ptr,
507 			  &boot_params.ext_cmd_line_ptr);
508 
509 	efi_stub_entry(handle, sys_table_arg, &boot_params);
510 	/* not reached */
511 
512 fail:
513 	efi_exit(handle, status);
514 }
515 
516 static void add_e820ext(struct boot_params *params,
517 			struct setup_data *e820ext, u32 nr_entries)
518 {
519 	struct setup_data *data;
520 
521 	e820ext->type = SETUP_E820_EXT;
522 	e820ext->len  = nr_entries * sizeof(struct boot_e820_entry);
523 	e820ext->next = 0;
524 
525 	data = (struct setup_data *)(unsigned long)params->hdr.setup_data;
526 
527 	while (data && data->next)
528 		data = (struct setup_data *)(unsigned long)data->next;
529 
530 	if (data)
531 		data->next = (unsigned long)e820ext;
532 	else
533 		params->hdr.setup_data = (unsigned long)e820ext;
534 }
535 
536 static efi_status_t
537 setup_e820(struct boot_params *params, struct setup_data *e820ext, u32 e820ext_size)
538 {
539 	struct boot_e820_entry *entry = params->e820_table;
540 	struct efi_info *efi = &params->efi_info;
541 	struct boot_e820_entry *prev = NULL;
542 	u32 nr_entries;
543 	u32 nr_desc;
544 	int i;
545 
546 	nr_entries = 0;
547 	nr_desc = efi->efi_memmap_size / efi->efi_memdesc_size;
548 
549 	for (i = 0; i < nr_desc; i++) {
550 		efi_memory_desc_t *d;
551 		unsigned int e820_type = 0;
552 		unsigned long m = efi->efi_memmap;
553 
554 #ifdef CONFIG_X86_64
555 		m |= (u64)efi->efi_memmap_hi << 32;
556 #endif
557 
558 		d = efi_early_memdesc_ptr(m, efi->efi_memdesc_size, i);
559 		switch (d->type) {
560 		case EFI_RESERVED_TYPE:
561 		case EFI_RUNTIME_SERVICES_CODE:
562 		case EFI_RUNTIME_SERVICES_DATA:
563 		case EFI_MEMORY_MAPPED_IO:
564 		case EFI_MEMORY_MAPPED_IO_PORT_SPACE:
565 		case EFI_PAL_CODE:
566 			e820_type = E820_TYPE_RESERVED;
567 			break;
568 
569 		case EFI_UNUSABLE_MEMORY:
570 			e820_type = E820_TYPE_UNUSABLE;
571 			break;
572 
573 		case EFI_ACPI_RECLAIM_MEMORY:
574 			e820_type = E820_TYPE_ACPI;
575 			break;
576 
577 		case EFI_LOADER_CODE:
578 		case EFI_LOADER_DATA:
579 		case EFI_BOOT_SERVICES_CODE:
580 		case EFI_BOOT_SERVICES_DATA:
581 		case EFI_CONVENTIONAL_MEMORY:
582 			if (efi_soft_reserve_enabled() &&
583 			    (d->attribute & EFI_MEMORY_SP))
584 				e820_type = E820_TYPE_SOFT_RESERVED;
585 			else
586 				e820_type = E820_TYPE_RAM;
587 			break;
588 
589 		case EFI_ACPI_MEMORY_NVS:
590 			e820_type = E820_TYPE_NVS;
591 			break;
592 
593 		case EFI_PERSISTENT_MEMORY:
594 			e820_type = E820_TYPE_PMEM;
595 			break;
596 
597 		case EFI_UNACCEPTED_MEMORY:
598 			if (!IS_ENABLED(CONFIG_UNACCEPTED_MEMORY))
599 				continue;
600 			e820_type = E820_TYPE_RAM;
601 			process_unaccepted_memory(d->phys_addr,
602 						  d->phys_addr + PAGE_SIZE * d->num_pages);
603 			break;
604 		default:
605 			continue;
606 		}
607 
608 		/* Merge adjacent mappings */
609 		if (prev && prev->type == e820_type &&
610 		    (prev->addr + prev->size) == d->phys_addr) {
611 			prev->size += d->num_pages << 12;
612 			continue;
613 		}
614 
615 		if (nr_entries == ARRAY_SIZE(params->e820_table)) {
616 			u32 need = (nr_desc - i) * sizeof(struct e820_entry) +
617 				   sizeof(struct setup_data);
618 
619 			if (!e820ext || e820ext_size < need)
620 				return EFI_BUFFER_TOO_SMALL;
621 
622 			/* boot_params map full, switch to e820 extended */
623 			entry = (struct boot_e820_entry *)e820ext->data;
624 		}
625 
626 		entry->addr = d->phys_addr;
627 		entry->size = d->num_pages << PAGE_SHIFT;
628 		entry->type = e820_type;
629 		prev = entry++;
630 		nr_entries++;
631 	}
632 
633 	if (nr_entries > ARRAY_SIZE(params->e820_table)) {
634 		u32 nr_e820ext = nr_entries - ARRAY_SIZE(params->e820_table);
635 
636 		add_e820ext(params, e820ext, nr_e820ext);
637 		nr_entries -= nr_e820ext;
638 	}
639 
640 	params->e820_entries = (u8)nr_entries;
641 
642 	return EFI_SUCCESS;
643 }
644 
645 static efi_status_t alloc_e820ext(u32 nr_desc, struct setup_data **e820ext,
646 				  u32 *e820ext_size)
647 {
648 	efi_status_t status;
649 	unsigned long size;
650 
651 	size = sizeof(struct setup_data) +
652 		sizeof(struct e820_entry) * nr_desc;
653 
654 	if (*e820ext) {
655 		efi_bs_call(free_pool, *e820ext);
656 		*e820ext = NULL;
657 		*e820ext_size = 0;
658 	}
659 
660 	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
661 			     (void **)e820ext);
662 	if (status == EFI_SUCCESS)
663 		*e820ext_size = size;
664 
665 	return status;
666 }
667 
668 static efi_status_t allocate_e820(struct boot_params *params,
669 				  struct setup_data **e820ext,
670 				  u32 *e820ext_size)
671 {
672 	struct efi_boot_memmap *map;
673 	efi_status_t status;
674 	__u32 nr_desc;
675 
676 	status = efi_get_memory_map(&map, false);
677 	if (status != EFI_SUCCESS)
678 		return status;
679 
680 	nr_desc = map->map_size / map->desc_size;
681 	if (nr_desc > ARRAY_SIZE(params->e820_table) - EFI_MMAP_NR_SLACK_SLOTS) {
682 		u32 nr_e820ext = nr_desc - ARRAY_SIZE(params->e820_table) +
683 				 EFI_MMAP_NR_SLACK_SLOTS;
684 
685 		status = alloc_e820ext(nr_e820ext, e820ext, e820ext_size);
686 	}
687 
688 	if (IS_ENABLED(CONFIG_UNACCEPTED_MEMORY) && status == EFI_SUCCESS)
689 		status = allocate_unaccepted_bitmap(nr_desc, map);
690 
691 	efi_bs_call(free_pool, map);
692 	return status;
693 }
694 
695 struct exit_boot_struct {
696 	struct boot_params	*boot_params;
697 	struct efi_info		*efi;
698 };
699 
700 static efi_status_t exit_boot_func(struct efi_boot_memmap *map,
701 				   void *priv)
702 {
703 	const char *signature;
704 	struct exit_boot_struct *p = priv;
705 
706 	signature = efi_is_64bit() ? EFI64_LOADER_SIGNATURE
707 				   : EFI32_LOADER_SIGNATURE;
708 	memcpy(&p->efi->efi_loader_signature, signature, sizeof(__u32));
709 
710 	efi_set_u64_split((unsigned long)efi_system_table,
711 			  &p->efi->efi_systab, &p->efi->efi_systab_hi);
712 	p->efi->efi_memdesc_size	= map->desc_size;
713 	p->efi->efi_memdesc_version	= map->desc_ver;
714 	efi_set_u64_split((unsigned long)map->map,
715 			  &p->efi->efi_memmap, &p->efi->efi_memmap_hi);
716 	p->efi->efi_memmap_size		= map->map_size;
717 
718 	return EFI_SUCCESS;
719 }
720 
721 static efi_status_t exit_boot(struct boot_params *boot_params, void *handle)
722 {
723 	struct setup_data *e820ext = NULL;
724 	__u32 e820ext_size = 0;
725 	efi_status_t status;
726 	struct exit_boot_struct priv;
727 
728 	priv.boot_params	= boot_params;
729 	priv.efi		= &boot_params->efi_info;
730 
731 	status = allocate_e820(boot_params, &e820ext, &e820ext_size);
732 	if (status != EFI_SUCCESS)
733 		return status;
734 
735 	/* Might as well exit boot services now */
736 	status = efi_exit_boot_services(handle, &priv, exit_boot_func);
737 	if (status != EFI_SUCCESS)
738 		return status;
739 
740 	/* Historic? */
741 	boot_params->alt_mem_k	= 32 * 1024;
742 
743 	status = setup_e820(boot_params, e820ext, e820ext_size);
744 	if (status != EFI_SUCCESS)
745 		return status;
746 
747 	return EFI_SUCCESS;
748 }
749 
750 static bool have_unsupported_snp_features(void)
751 {
752 	u64 unsupported;
753 
754 	unsupported = snp_get_unsupported_features(sev_get_status());
755 	if (unsupported) {
756 		efi_err("Unsupported SEV-SNP features detected: 0x%llx\n",
757 			unsupported);
758 		return true;
759 	}
760 	return false;
761 }
762 
763 static void efi_get_seed(void *seed, int size)
764 {
765 	efi_get_random_bytes(size, seed);
766 
767 	/*
768 	 * This only updates seed[0] when running on 32-bit, but in that case,
769 	 * seed[1] is not used anyway, as there is no virtual KASLR on 32-bit.
770 	 */
771 	*(unsigned long *)seed ^= kaslr_get_random_long("EFI");
772 }
773 
774 static void error(char *str)
775 {
776 	efi_warn("Decompression failed: %s\n", str);
777 }
778 
779 static efi_status_t efi_decompress_kernel(unsigned long *kernel_entry)
780 {
781 	unsigned long virt_addr = LOAD_PHYSICAL_ADDR;
782 	unsigned long addr, alloc_size, entry;
783 	efi_status_t status;
784 	u32 seed[2] = {};
785 
786 	/* determine the required size of the allocation */
787 	alloc_size = ALIGN(max_t(unsigned long, output_len, kernel_total_size),
788 			   MIN_KERNEL_ALIGN);
789 
790 	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && !efi_nokaslr) {
791 		u64 range = KERNEL_IMAGE_SIZE - LOAD_PHYSICAL_ADDR - kernel_total_size;
792 		static const efi_char16_t ami[] = L"American Megatrends";
793 
794 		efi_get_seed(seed, sizeof(seed));
795 
796 		virt_addr += (range * seed[1]) >> 32;
797 		virt_addr &= ~(CONFIG_PHYSICAL_ALIGN - 1);
798 
799 		/*
800 		 * Older Dell systems with AMI UEFI firmware v2.0 may hang
801 		 * while decompressing the kernel if physical address
802 		 * randomization is enabled.
803 		 *
804 		 * https://bugzilla.kernel.org/show_bug.cgi?id=218173
805 		 */
806 		if (efi_system_table->hdr.revision <= EFI_2_00_SYSTEM_TABLE_REVISION &&
807 		    !memcmp(efistub_fw_vendor(), ami, sizeof(ami))) {
808 			efi_debug("AMI firmware v2.0 or older detected - disabling physical KASLR\n");
809 			seed[0] = 0;
810 		}
811 	}
812 
813 	status = efi_random_alloc(alloc_size, CONFIG_PHYSICAL_ALIGN, &addr,
814 				  seed[0], EFI_LOADER_CODE,
815 				  LOAD_PHYSICAL_ADDR,
816 				  EFI_X86_KERNEL_ALLOC_LIMIT);
817 	if (status != EFI_SUCCESS)
818 		return status;
819 
820 	entry = decompress_kernel((void *)addr, virt_addr, error);
821 	if (entry == ULONG_MAX) {
822 		efi_free(alloc_size, addr);
823 		return EFI_LOAD_ERROR;
824 	}
825 
826 	*kernel_entry = addr + entry;
827 
828 	return efi_adjust_memory_range_protection(addr, kernel_text_size);
829 }
830 
831 static void __noreturn enter_kernel(unsigned long kernel_addr,
832 				    struct boot_params *boot_params)
833 {
834 	/* enter decompressed kernel with boot_params pointer in RSI/ESI */
835 	asm("jmp *%0"::"r"(kernel_addr), "S"(boot_params));
836 
837 	unreachable();
838 }
839 
840 /*
841  * On success, this routine will jump to the relocated image directly and never
842  * return.  On failure, it will exit to the firmware via efi_exit() instead of
843  * returning.
844  */
845 void __noreturn efi_stub_entry(efi_handle_t handle,
846 			       efi_system_table_t *sys_table_arg,
847 			       struct boot_params *boot_params)
848 {
849 	efi_guid_t guid = EFI_MEMORY_ATTRIBUTE_PROTOCOL_GUID;
850 	struct setup_header *hdr = &boot_params->hdr;
851 	const struct linux_efi_initrd *initrd = NULL;
852 	unsigned long kernel_entry;
853 	efi_status_t status;
854 
855 	boot_params_pointer = boot_params;
856 
857 	efi_system_table = sys_table_arg;
858 	/* Check if we were booted by the EFI firmware */
859 	if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
860 		efi_exit(handle, EFI_INVALID_PARAMETER);
861 
862 	if (have_unsupported_snp_features())
863 		efi_exit(handle, EFI_UNSUPPORTED);
864 
865 	if (IS_ENABLED(CONFIG_EFI_DXE_MEM_ATTRIBUTES)) {
866 		efi_dxe_table = get_efi_config_table(EFI_DXE_SERVICES_TABLE_GUID);
867 		if (efi_dxe_table &&
868 		    efi_dxe_table->hdr.signature != EFI_DXE_SERVICES_TABLE_SIGNATURE) {
869 			efi_warn("Ignoring DXE services table: invalid signature\n");
870 			efi_dxe_table = NULL;
871 		}
872 	}
873 
874 	/* grab the memory attributes protocol if it exists */
875 	efi_bs_call(locate_protocol, &guid, NULL, (void **)&memattr);
876 
877 	status = efi_setup_5level_paging();
878 	if (status != EFI_SUCCESS) {
879 		efi_err("efi_setup_5level_paging() failed!\n");
880 		goto fail;
881 	}
882 
883 #ifdef CONFIG_CMDLINE_BOOL
884 	status = efi_parse_options(CONFIG_CMDLINE);
885 	if (status != EFI_SUCCESS) {
886 		efi_err("Failed to parse options\n");
887 		goto fail;
888 	}
889 #endif
890 	if (!IS_ENABLED(CONFIG_CMDLINE_OVERRIDE)) {
891 		unsigned long cmdline_paddr = ((u64)hdr->cmd_line_ptr |
892 					       ((u64)boot_params->ext_cmd_line_ptr << 32));
893 		status = efi_parse_options((char *)cmdline_paddr);
894 		if (status != EFI_SUCCESS) {
895 			efi_err("Failed to parse options\n");
896 			goto fail;
897 		}
898 	}
899 
900 	if (efi_mem_encrypt > 0)
901 		hdr->xloadflags |= XLF_MEM_ENCRYPTION;
902 
903 	status = efi_decompress_kernel(&kernel_entry);
904 	if (status != EFI_SUCCESS) {
905 		efi_err("Failed to decompress kernel\n");
906 		goto fail;
907 	}
908 
909 	/*
910 	 * At this point, an initrd may already have been loaded by the
911 	 * bootloader and passed via bootparams. We permit an initrd loaded
912 	 * from the LINUX_EFI_INITRD_MEDIA_GUID device path to supersede it.
913 	 *
914 	 * If the device path is not present, any command-line initrd=
915 	 * arguments will be processed only if image is not NULL, which will be
916 	 * the case only if we were loaded via the PE entry point.
917 	 */
918 	status = efi_load_initrd(image, hdr->initrd_addr_max, ULONG_MAX,
919 				 &initrd);
920 	if (status != EFI_SUCCESS)
921 		goto fail;
922 	if (initrd && initrd->size > 0) {
923 		efi_set_u64_split(initrd->base, &hdr->ramdisk_image,
924 				  &boot_params->ext_ramdisk_image);
925 		efi_set_u64_split(initrd->size, &hdr->ramdisk_size,
926 				  &boot_params->ext_ramdisk_size);
927 	}
928 
929 
930 	/*
931 	 * If the boot loader gave us a value for secure_boot then we use that,
932 	 * otherwise we ask the BIOS.
933 	 */
934 	if (boot_params->secure_boot == efi_secureboot_mode_unset)
935 		boot_params->secure_boot = efi_get_secureboot();
936 
937 	/* Ask the firmware to clear memory on unclean shutdown */
938 	efi_enable_reset_attack_mitigation();
939 
940 	efi_random_get_seed();
941 
942 	efi_retrieve_tpm2_eventlog();
943 
944 	setup_graphics(boot_params);
945 
946 	setup_efi_pci(boot_params);
947 
948 	setup_quirks(boot_params);
949 
950 	setup_unaccepted_memory();
951 
952 	status = exit_boot(boot_params, handle);
953 	if (status != EFI_SUCCESS) {
954 		efi_err("exit_boot() failed!\n");
955 		goto fail;
956 	}
957 
958 	/*
959 	 * Call the SEV init code while still running with the firmware's
960 	 * GDT/IDT, so #VC exceptions will be handled by EFI.
961 	 */
962 	sev_enable(boot_params);
963 
964 	efi_5level_switch();
965 
966 	enter_kernel(kernel_entry, boot_params);
967 fail:
968 	efi_err("efi_stub_entry() failed!\n");
969 
970 	efi_exit(handle, status);
971 }
972 
973 #ifdef CONFIG_EFI_HANDOVER_PROTOCOL
974 void efi_handover_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
975 			struct boot_params *boot_params)
976 {
977 	memset(_bss, 0, _ebss - _bss);
978 	efi_stub_entry(handle, sys_table_arg, boot_params);
979 }
980 
981 #ifndef CONFIG_EFI_MIXED
982 extern __alias(efi_handover_entry)
983 void efi32_stub_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
984 		      struct boot_params *boot_params);
985 
986 extern __alias(efi_handover_entry)
987 void efi64_stub_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
988 		      struct boot_params *boot_params);
989 #endif
990 #endif
991