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 
19 #include "efistub.h"
20 
21 /* Maximum physical address for 64-bit kernel with 4-level paging */
22 #define MAXMEM_X86_64_4LEVEL (1ull << 46)
23 
24 const efi_system_table_t *efi_system_table;
25 extern u32 image_offset;
26 static efi_loaded_image_t *image = NULL;
27 
28 static efi_status_t
29 preserve_pci_rom_image(efi_pci_io_protocol_t *pci, struct pci_setup_rom **__rom)
30 {
31 	struct pci_setup_rom *rom = NULL;
32 	efi_status_t status;
33 	unsigned long size;
34 	uint64_t romsize;
35 	void *romimage;
36 
37 	/*
38 	 * Some firmware images contain EFI function pointers at the place where
39 	 * the romimage and romsize fields are supposed to be. Typically the EFI
40 	 * code is mapped at high addresses, translating to an unrealistically
41 	 * large romsize. The UEFI spec limits the size of option ROMs to 16
42 	 * MiB so we reject any ROMs over 16 MiB in size to catch this.
43 	 */
44 	romimage = efi_table_attr(pci, romimage);
45 	romsize = efi_table_attr(pci, romsize);
46 	if (!romimage || !romsize || romsize > SZ_16M)
47 		return EFI_INVALID_PARAMETER;
48 
49 	size = romsize + sizeof(*rom);
50 
51 	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
52 			     (void **)&rom);
53 	if (status != EFI_SUCCESS) {
54 		efi_err("Failed to allocate memory for 'rom'\n");
55 		return status;
56 	}
57 
58 	memset(rom, 0, sizeof(*rom));
59 
60 	rom->data.type	= SETUP_PCI;
61 	rom->data.len	= size - sizeof(struct setup_data);
62 	rom->data.next	= 0;
63 	rom->pcilen	= pci->romsize;
64 	*__rom = rom;
65 
66 	status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16,
67 				PCI_VENDOR_ID, 1, &rom->vendor);
68 
69 	if (status != EFI_SUCCESS) {
70 		efi_err("Failed to read rom->vendor\n");
71 		goto free_struct;
72 	}
73 
74 	status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16,
75 				PCI_DEVICE_ID, 1, &rom->devid);
76 
77 	if (status != EFI_SUCCESS) {
78 		efi_err("Failed to read rom->devid\n");
79 		goto free_struct;
80 	}
81 
82 	status = efi_call_proto(pci, get_location, &rom->segment, &rom->bus,
83 				&rom->device, &rom->function);
84 
85 	if (status != EFI_SUCCESS)
86 		goto free_struct;
87 
88 	memcpy(rom->romdata, romimage, romsize);
89 	return status;
90 
91 free_struct:
92 	efi_bs_call(free_pool, rom);
93 	return status;
94 }
95 
96 /*
97  * There's no way to return an informative status from this function,
98  * because any analysis (and printing of error messages) needs to be
99  * done directly at the EFI function call-site.
100  *
101  * For example, EFI_INVALID_PARAMETER could indicate a bug or maybe we
102  * just didn't find any PCI devices, but there's no way to tell outside
103  * the context of the call.
104  */
105 static void setup_efi_pci(struct boot_params *params)
106 {
107 	efi_status_t status;
108 	void **pci_handle = NULL;
109 	efi_guid_t pci_proto = EFI_PCI_IO_PROTOCOL_GUID;
110 	unsigned long size = 0;
111 	struct setup_data *data;
112 	efi_handle_t h;
113 	int i;
114 
115 	status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
116 			     &pci_proto, NULL, &size, pci_handle);
117 
118 	if (status == EFI_BUFFER_TOO_SMALL) {
119 		status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
120 				     (void **)&pci_handle);
121 
122 		if (status != EFI_SUCCESS) {
123 			efi_err("Failed to allocate memory for 'pci_handle'\n");
124 			return;
125 		}
126 
127 		status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
128 				     &pci_proto, NULL, &size, pci_handle);
129 	}
130 
131 	if (status != EFI_SUCCESS)
132 		goto free_handle;
133 
134 	data = (struct setup_data *)(unsigned long)params->hdr.setup_data;
135 
136 	while (data && data->next)
137 		data = (struct setup_data *)(unsigned long)data->next;
138 
139 	for_each_efi_handle(h, pci_handle, size, i) {
140 		efi_pci_io_protocol_t *pci = NULL;
141 		struct pci_setup_rom *rom;
142 
143 		status = efi_bs_call(handle_protocol, h, &pci_proto,
144 				     (void **)&pci);
145 		if (status != EFI_SUCCESS || !pci)
146 			continue;
147 
148 		status = preserve_pci_rom_image(pci, &rom);
149 		if (status != EFI_SUCCESS)
150 			continue;
151 
152 		if (data)
153 			data->next = (unsigned long)rom;
154 		else
155 			params->hdr.setup_data = (unsigned long)rom;
156 
157 		data = (struct setup_data *)rom;
158 	}
159 
160 free_handle:
161 	efi_bs_call(free_pool, pci_handle);
162 }
163 
164 static void retrieve_apple_device_properties(struct boot_params *boot_params)
165 {
166 	efi_guid_t guid = APPLE_PROPERTIES_PROTOCOL_GUID;
167 	struct setup_data *data, *new;
168 	efi_status_t status;
169 	u32 size = 0;
170 	apple_properties_protocol_t *p;
171 
172 	status = efi_bs_call(locate_protocol, &guid, NULL, (void **)&p);
173 	if (status != EFI_SUCCESS)
174 		return;
175 
176 	if (efi_table_attr(p, version) != 0x10000) {
177 		efi_err("Unsupported properties proto version\n");
178 		return;
179 	}
180 
181 	efi_call_proto(p, get_all, NULL, &size);
182 	if (!size)
183 		return;
184 
185 	do {
186 		status = efi_bs_call(allocate_pool, EFI_LOADER_DATA,
187 				     size + sizeof(struct setup_data),
188 				     (void **)&new);
189 		if (status != EFI_SUCCESS) {
190 			efi_err("Failed to allocate memory for 'properties'\n");
191 			return;
192 		}
193 
194 		status = efi_call_proto(p, get_all, new->data, &size);
195 
196 		if (status == EFI_BUFFER_TOO_SMALL)
197 			efi_bs_call(free_pool, new);
198 	} while (status == EFI_BUFFER_TOO_SMALL);
199 
200 	new->type = SETUP_APPLE_PROPERTIES;
201 	new->len  = size;
202 	new->next = 0;
203 
204 	data = (struct setup_data *)(unsigned long)boot_params->hdr.setup_data;
205 	if (!data) {
206 		boot_params->hdr.setup_data = (unsigned long)new;
207 	} else {
208 		while (data->next)
209 			data = (struct setup_data *)(unsigned long)data->next;
210 		data->next = (unsigned long)new;
211 	}
212 }
213 
214 static const efi_char16_t apple[] = L"Apple";
215 
216 static void setup_quirks(struct boot_params *boot_params)
217 {
218 	efi_char16_t *fw_vendor = (efi_char16_t *)(unsigned long)
219 		efi_table_attr(efi_system_table, fw_vendor);
220 
221 	if (!memcmp(fw_vendor, apple, sizeof(apple))) {
222 		if (IS_ENABLED(CONFIG_APPLE_PROPERTIES))
223 			retrieve_apple_device_properties(boot_params);
224 	}
225 }
226 
227 /*
228  * See if we have Universal Graphics Adapter (UGA) protocol
229  */
230 static efi_status_t
231 setup_uga(struct screen_info *si, efi_guid_t *uga_proto, unsigned long size)
232 {
233 	efi_status_t status;
234 	u32 width, height;
235 	void **uga_handle = NULL;
236 	efi_uga_draw_protocol_t *uga = NULL, *first_uga;
237 	efi_handle_t handle;
238 	int i;
239 
240 	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
241 			     (void **)&uga_handle);
242 	if (status != EFI_SUCCESS)
243 		return status;
244 
245 	status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
246 			     uga_proto, NULL, &size, uga_handle);
247 	if (status != EFI_SUCCESS)
248 		goto free_handle;
249 
250 	height = 0;
251 	width = 0;
252 
253 	first_uga = NULL;
254 	for_each_efi_handle(handle, uga_handle, size, i) {
255 		efi_guid_t pciio_proto = EFI_PCI_IO_PROTOCOL_GUID;
256 		u32 w, h, depth, refresh;
257 		void *pciio;
258 
259 		status = efi_bs_call(handle_protocol, handle, uga_proto,
260 				     (void **)&uga);
261 		if (status != EFI_SUCCESS)
262 			continue;
263 
264 		pciio = NULL;
265 		efi_bs_call(handle_protocol, handle, &pciio_proto, &pciio);
266 
267 		status = efi_call_proto(uga, get_mode, &w, &h, &depth, &refresh);
268 		if (status == EFI_SUCCESS && (!first_uga || pciio)) {
269 			width = w;
270 			height = h;
271 
272 			/*
273 			 * Once we've found a UGA supporting PCIIO,
274 			 * don't bother looking any further.
275 			 */
276 			if (pciio)
277 				break;
278 
279 			first_uga = uga;
280 		}
281 	}
282 
283 	if (!width && !height)
284 		goto free_handle;
285 
286 	/* EFI framebuffer */
287 	si->orig_video_isVGA	= VIDEO_TYPE_EFI;
288 
289 	si->lfb_depth		= 32;
290 	si->lfb_width		= width;
291 	si->lfb_height		= height;
292 
293 	si->red_size		= 8;
294 	si->red_pos		= 16;
295 	si->green_size		= 8;
296 	si->green_pos		= 8;
297 	si->blue_size		= 8;
298 	si->blue_pos		= 0;
299 	si->rsvd_size		= 8;
300 	si->rsvd_pos		= 24;
301 
302 free_handle:
303 	efi_bs_call(free_pool, uga_handle);
304 
305 	return status;
306 }
307 
308 static void setup_graphics(struct boot_params *boot_params)
309 {
310 	efi_guid_t graphics_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
311 	struct screen_info *si;
312 	efi_guid_t uga_proto = EFI_UGA_PROTOCOL_GUID;
313 	efi_status_t status;
314 	unsigned long size;
315 	void **gop_handle = NULL;
316 	void **uga_handle = NULL;
317 
318 	si = &boot_params->screen_info;
319 	memset(si, 0, sizeof(*si));
320 
321 	size = 0;
322 	status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
323 			     &graphics_proto, NULL, &size, gop_handle);
324 	if (status == EFI_BUFFER_TOO_SMALL)
325 		status = efi_setup_gop(si, &graphics_proto, size);
326 
327 	if (status != EFI_SUCCESS) {
328 		size = 0;
329 		status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
330 				     &uga_proto, NULL, &size, uga_handle);
331 		if (status == EFI_BUFFER_TOO_SMALL)
332 			setup_uga(si, &uga_proto, size);
333 	}
334 }
335 
336 
337 static void __noreturn efi_exit(efi_handle_t handle, efi_status_t status)
338 {
339 	efi_bs_call(exit, handle, status, 0, NULL);
340 	for(;;)
341 		asm("hlt");
342 }
343 
344 void startup_32(struct boot_params *boot_params);
345 
346 void __noreturn efi_stub_entry(efi_handle_t handle,
347 			       efi_system_table_t *sys_table_arg,
348 			       struct boot_params *boot_params);
349 
350 /*
351  * Because the x86 boot code expects to be passed a boot_params we
352  * need to create one ourselves (usually the bootloader would create
353  * one for us).
354  */
355 efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
356 				   efi_system_table_t *sys_table_arg)
357 {
358 	struct boot_params *boot_params;
359 	struct setup_header *hdr;
360 	void *image_base;
361 	efi_guid_t proto = LOADED_IMAGE_PROTOCOL_GUID;
362 	int options_size = 0;
363 	efi_status_t status;
364 	char *cmdline_ptr;
365 
366 	efi_system_table = sys_table_arg;
367 
368 	/* Check if we were booted by the EFI firmware */
369 	if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
370 		efi_exit(handle, EFI_INVALID_PARAMETER);
371 
372 	status = efi_bs_call(handle_protocol, handle, &proto, (void **)&image);
373 	if (status != EFI_SUCCESS) {
374 		efi_err("Failed to get handle for LOADED_IMAGE_PROTOCOL\n");
375 		efi_exit(handle, status);
376 	}
377 
378 	image_base = efi_table_attr(image, image_base);
379 	image_offset = (void *)startup_32 - image_base;
380 
381 	status = efi_allocate_pages(sizeof(struct boot_params),
382 				    (unsigned long *)&boot_params, ULONG_MAX);
383 	if (status != EFI_SUCCESS) {
384 		efi_err("Failed to allocate lowmem for boot params\n");
385 		efi_exit(handle, status);
386 	}
387 
388 	memset(boot_params, 0x0, sizeof(struct boot_params));
389 
390 	hdr = &boot_params->hdr;
391 
392 	/* Copy the setup header from the second sector to boot_params */
393 	memcpy(&hdr->jump, image_base + 512,
394 	       sizeof(struct setup_header) - offsetof(struct setup_header, jump));
395 
396 	/*
397 	 * Fill out some of the header fields ourselves because the
398 	 * EFI firmware loader doesn't load the first sector.
399 	 */
400 	hdr->root_flags	= 1;
401 	hdr->vid_mode	= 0xffff;
402 	hdr->boot_flag	= 0xAA55;
403 
404 	hdr->type_of_loader = 0x21;
405 
406 	/* Convert unicode cmdline to ascii */
407 	cmdline_ptr = efi_convert_cmdline(image, &options_size);
408 	if (!cmdline_ptr)
409 		goto fail;
410 
411 	efi_set_u64_split((unsigned long)cmdline_ptr,
412 			  &hdr->cmd_line_ptr, &boot_params->ext_cmd_line_ptr);
413 
414 	hdr->ramdisk_image = 0;
415 	hdr->ramdisk_size = 0;
416 
417 	efi_stub_entry(handle, sys_table_arg, boot_params);
418 	/* not reached */
419 
420 fail:
421 	efi_free(sizeof(struct boot_params), (unsigned long)boot_params);
422 
423 	efi_exit(handle, status);
424 }
425 
426 static void add_e820ext(struct boot_params *params,
427 			struct setup_data *e820ext, u32 nr_entries)
428 {
429 	struct setup_data *data;
430 
431 	e820ext->type = SETUP_E820_EXT;
432 	e820ext->len  = nr_entries * sizeof(struct boot_e820_entry);
433 	e820ext->next = 0;
434 
435 	data = (struct setup_data *)(unsigned long)params->hdr.setup_data;
436 
437 	while (data && data->next)
438 		data = (struct setup_data *)(unsigned long)data->next;
439 
440 	if (data)
441 		data->next = (unsigned long)e820ext;
442 	else
443 		params->hdr.setup_data = (unsigned long)e820ext;
444 }
445 
446 static efi_status_t
447 setup_e820(struct boot_params *params, struct setup_data *e820ext, u32 e820ext_size)
448 {
449 	struct boot_e820_entry *entry = params->e820_table;
450 	struct efi_info *efi = &params->efi_info;
451 	struct boot_e820_entry *prev = NULL;
452 	u32 nr_entries;
453 	u32 nr_desc;
454 	int i;
455 
456 	nr_entries = 0;
457 	nr_desc = efi->efi_memmap_size / efi->efi_memdesc_size;
458 
459 	for (i = 0; i < nr_desc; i++) {
460 		efi_memory_desc_t *d;
461 		unsigned int e820_type = 0;
462 		unsigned long m = efi->efi_memmap;
463 
464 #ifdef CONFIG_X86_64
465 		m |= (u64)efi->efi_memmap_hi << 32;
466 #endif
467 
468 		d = efi_early_memdesc_ptr(m, efi->efi_memdesc_size, i);
469 		switch (d->type) {
470 		case EFI_RESERVED_TYPE:
471 		case EFI_RUNTIME_SERVICES_CODE:
472 		case EFI_RUNTIME_SERVICES_DATA:
473 		case EFI_MEMORY_MAPPED_IO:
474 		case EFI_MEMORY_MAPPED_IO_PORT_SPACE:
475 		case EFI_PAL_CODE:
476 			e820_type = E820_TYPE_RESERVED;
477 			break;
478 
479 		case EFI_UNUSABLE_MEMORY:
480 			e820_type = E820_TYPE_UNUSABLE;
481 			break;
482 
483 		case EFI_ACPI_RECLAIM_MEMORY:
484 			e820_type = E820_TYPE_ACPI;
485 			break;
486 
487 		case EFI_LOADER_CODE:
488 		case EFI_LOADER_DATA:
489 		case EFI_BOOT_SERVICES_CODE:
490 		case EFI_BOOT_SERVICES_DATA:
491 		case EFI_CONVENTIONAL_MEMORY:
492 			if (efi_soft_reserve_enabled() &&
493 			    (d->attribute & EFI_MEMORY_SP))
494 				e820_type = E820_TYPE_SOFT_RESERVED;
495 			else
496 				e820_type = E820_TYPE_RAM;
497 			break;
498 
499 		case EFI_ACPI_MEMORY_NVS:
500 			e820_type = E820_TYPE_NVS;
501 			break;
502 
503 		case EFI_PERSISTENT_MEMORY:
504 			e820_type = E820_TYPE_PMEM;
505 			break;
506 
507 		default:
508 			continue;
509 		}
510 
511 		/* Merge adjacent mappings */
512 		if (prev && prev->type == e820_type &&
513 		    (prev->addr + prev->size) == d->phys_addr) {
514 			prev->size += d->num_pages << 12;
515 			continue;
516 		}
517 
518 		if (nr_entries == ARRAY_SIZE(params->e820_table)) {
519 			u32 need = (nr_desc - i) * sizeof(struct e820_entry) +
520 				   sizeof(struct setup_data);
521 
522 			if (!e820ext || e820ext_size < need)
523 				return EFI_BUFFER_TOO_SMALL;
524 
525 			/* boot_params map full, switch to e820 extended */
526 			entry = (struct boot_e820_entry *)e820ext->data;
527 		}
528 
529 		entry->addr = d->phys_addr;
530 		entry->size = d->num_pages << PAGE_SHIFT;
531 		entry->type = e820_type;
532 		prev = entry++;
533 		nr_entries++;
534 	}
535 
536 	if (nr_entries > ARRAY_SIZE(params->e820_table)) {
537 		u32 nr_e820ext = nr_entries - ARRAY_SIZE(params->e820_table);
538 
539 		add_e820ext(params, e820ext, nr_e820ext);
540 		nr_entries -= nr_e820ext;
541 	}
542 
543 	params->e820_entries = (u8)nr_entries;
544 
545 	return EFI_SUCCESS;
546 }
547 
548 static efi_status_t alloc_e820ext(u32 nr_desc, struct setup_data **e820ext,
549 				  u32 *e820ext_size)
550 {
551 	efi_status_t status;
552 	unsigned long size;
553 
554 	size = sizeof(struct setup_data) +
555 		sizeof(struct e820_entry) * nr_desc;
556 
557 	if (*e820ext) {
558 		efi_bs_call(free_pool, *e820ext);
559 		*e820ext = NULL;
560 		*e820ext_size = 0;
561 	}
562 
563 	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
564 			     (void **)e820ext);
565 	if (status == EFI_SUCCESS)
566 		*e820ext_size = size;
567 
568 	return status;
569 }
570 
571 static efi_status_t allocate_e820(struct boot_params *params,
572 				  struct setup_data **e820ext,
573 				  u32 *e820ext_size)
574 {
575 	unsigned long map_size, desc_size, map_key;
576 	efi_status_t status;
577 	__u32 nr_desc, desc_version;
578 
579 	/* Only need the size of the mem map and size of each mem descriptor */
580 	map_size = 0;
581 	status = efi_bs_call(get_memory_map, &map_size, NULL, &map_key,
582 			     &desc_size, &desc_version);
583 	if (status != EFI_BUFFER_TOO_SMALL)
584 		return (status != EFI_SUCCESS) ? status : EFI_UNSUPPORTED;
585 
586 	nr_desc = map_size / desc_size + EFI_MMAP_NR_SLACK_SLOTS;
587 
588 	if (nr_desc > ARRAY_SIZE(params->e820_table)) {
589 		u32 nr_e820ext = nr_desc - ARRAY_SIZE(params->e820_table);
590 
591 		status = alloc_e820ext(nr_e820ext, e820ext, e820ext_size);
592 		if (status != EFI_SUCCESS)
593 			return status;
594 	}
595 
596 	return EFI_SUCCESS;
597 }
598 
599 struct exit_boot_struct {
600 	struct boot_params	*boot_params;
601 	struct efi_info		*efi;
602 };
603 
604 static efi_status_t exit_boot_func(struct efi_boot_memmap *map,
605 				   void *priv)
606 {
607 	const char *signature;
608 	struct exit_boot_struct *p = priv;
609 
610 	signature = efi_is_64bit() ? EFI64_LOADER_SIGNATURE
611 				   : EFI32_LOADER_SIGNATURE;
612 	memcpy(&p->efi->efi_loader_signature, signature, sizeof(__u32));
613 
614 	efi_set_u64_split((unsigned long)efi_system_table,
615 			  &p->efi->efi_systab, &p->efi->efi_systab_hi);
616 	p->efi->efi_memdesc_size	= *map->desc_size;
617 	p->efi->efi_memdesc_version	= *map->desc_ver;
618 	efi_set_u64_split((unsigned long)*map->map,
619 			  &p->efi->efi_memmap, &p->efi->efi_memmap_hi);
620 	p->efi->efi_memmap_size		= *map->map_size;
621 
622 	return EFI_SUCCESS;
623 }
624 
625 static efi_status_t exit_boot(struct boot_params *boot_params, void *handle)
626 {
627 	unsigned long map_sz, key, desc_size, buff_size;
628 	efi_memory_desc_t *mem_map;
629 	struct setup_data *e820ext = NULL;
630 	__u32 e820ext_size = 0;
631 	efi_status_t status;
632 	__u32 desc_version;
633 	struct efi_boot_memmap map;
634 	struct exit_boot_struct priv;
635 
636 	map.map			= &mem_map;
637 	map.map_size		= &map_sz;
638 	map.desc_size		= &desc_size;
639 	map.desc_ver		= &desc_version;
640 	map.key_ptr		= &key;
641 	map.buff_size		= &buff_size;
642 	priv.boot_params	= boot_params;
643 	priv.efi		= &boot_params->efi_info;
644 
645 	status = allocate_e820(boot_params, &e820ext, &e820ext_size);
646 	if (status != EFI_SUCCESS)
647 		return status;
648 
649 	/* Might as well exit boot services now */
650 	status = efi_exit_boot_services(handle, &map, &priv, exit_boot_func);
651 	if (status != EFI_SUCCESS)
652 		return status;
653 
654 	/* Historic? */
655 	boot_params->alt_mem_k	= 32 * 1024;
656 
657 	status = setup_e820(boot_params, e820ext, e820ext_size);
658 	if (status != EFI_SUCCESS)
659 		return status;
660 
661 	return EFI_SUCCESS;
662 }
663 
664 /*
665  * On success, we return the address of startup_32, which has potentially been
666  * relocated by efi_relocate_kernel.
667  * On failure, we exit to the firmware via efi_exit instead of returning.
668  */
669 unsigned long efi_main(efi_handle_t handle,
670 			     efi_system_table_t *sys_table_arg,
671 			     struct boot_params *boot_params)
672 {
673 	unsigned long bzimage_addr = (unsigned long)startup_32;
674 	unsigned long buffer_start, buffer_end;
675 	struct setup_header *hdr = &boot_params->hdr;
676 	efi_status_t status;
677 
678 	efi_system_table = sys_table_arg;
679 
680 	/* Check if we were booted by the EFI firmware */
681 	if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
682 		efi_exit(handle, EFI_INVALID_PARAMETER);
683 
684 	/*
685 	 * If the kernel isn't already loaded at a suitable address,
686 	 * relocate it.
687 	 *
688 	 * It must be loaded above LOAD_PHYSICAL_ADDR.
689 	 *
690 	 * The maximum address for 64-bit is 1 << 46 for 4-level paging. This
691 	 * is defined as the macro MAXMEM, but unfortunately that is not a
692 	 * compile-time constant if 5-level paging is configured, so we instead
693 	 * define our own macro for use here.
694 	 *
695 	 * For 32-bit, the maximum address is complicated to figure out, for
696 	 * now use KERNEL_IMAGE_SIZE, which will be 512MiB, the same as what
697 	 * KASLR uses.
698 	 *
699 	 * Also relocate it if image_offset is zero, i.e. the kernel wasn't
700 	 * loaded by LoadImage, but rather by a bootloader that called the
701 	 * handover entry. The reason we must always relocate in this case is
702 	 * to handle the case of systemd-boot booting a unified kernel image,
703 	 * which is a PE executable that contains the bzImage and an initrd as
704 	 * COFF sections. The initrd section is placed after the bzImage
705 	 * without ensuring that there are at least init_size bytes available
706 	 * for the bzImage, and thus the compressed kernel's startup code may
707 	 * overwrite the initrd unless it is moved out of the way.
708 	 */
709 
710 	buffer_start = ALIGN(bzimage_addr - image_offset,
711 			     hdr->kernel_alignment);
712 	buffer_end = buffer_start + hdr->init_size;
713 
714 	if ((buffer_start < LOAD_PHYSICAL_ADDR)				     ||
715 	    (IS_ENABLED(CONFIG_X86_32) && buffer_end > KERNEL_IMAGE_SIZE)    ||
716 	    (IS_ENABLED(CONFIG_X86_64) && buffer_end > MAXMEM_X86_64_4LEVEL) ||
717 	    (image_offset == 0)) {
718 		extern char _bss[];
719 
720 		status = efi_relocate_kernel(&bzimage_addr,
721 					     (unsigned long)_bss - bzimage_addr,
722 					     hdr->init_size,
723 					     hdr->pref_address,
724 					     hdr->kernel_alignment,
725 					     LOAD_PHYSICAL_ADDR);
726 		if (status != EFI_SUCCESS) {
727 			efi_err("efi_relocate_kernel() failed!\n");
728 			goto fail;
729 		}
730 		/*
731 		 * Now that we've copied the kernel elsewhere, we no longer
732 		 * have a set up block before startup_32(), so reset image_offset
733 		 * to zero in case it was set earlier.
734 		 */
735 		image_offset = 0;
736 	}
737 
738 #ifdef CONFIG_CMDLINE_BOOL
739 	status = efi_parse_options(CONFIG_CMDLINE);
740 	if (status != EFI_SUCCESS) {
741 		efi_err("Failed to parse options\n");
742 		goto fail;
743 	}
744 #endif
745 	if (!IS_ENABLED(CONFIG_CMDLINE_OVERRIDE)) {
746 		unsigned long cmdline_paddr = ((u64)hdr->cmd_line_ptr |
747 					       ((u64)boot_params->ext_cmd_line_ptr << 32));
748 		status = efi_parse_options((char *)cmdline_paddr);
749 		if (status != EFI_SUCCESS) {
750 			efi_err("Failed to parse options\n");
751 			goto fail;
752 		}
753 	}
754 
755 	/*
756 	 * At this point, an initrd may already have been loaded by the
757 	 * bootloader and passed via bootparams. We permit an initrd loaded
758 	 * from the LINUX_EFI_INITRD_MEDIA_GUID device path to supersede it.
759 	 *
760 	 * If the device path is not present, any command-line initrd=
761 	 * arguments will be processed only if image is not NULL, which will be
762 	 * the case only if we were loaded via the PE entry point.
763 	 */
764 	if (!efi_noinitrd) {
765 		unsigned long addr, size;
766 
767 		status = efi_load_initrd(image, &addr, &size,
768 					 hdr->initrd_addr_max, ULONG_MAX);
769 
770 		if (status != EFI_SUCCESS) {
771 			efi_err("Failed to load initrd!\n");
772 			goto fail;
773 		}
774 		if (size > 0) {
775 			efi_set_u64_split(addr, &hdr->ramdisk_image,
776 					  &boot_params->ext_ramdisk_image);
777 			efi_set_u64_split(size, &hdr->ramdisk_size,
778 					  &boot_params->ext_ramdisk_size);
779 		}
780 	}
781 
782 	/*
783 	 * If the boot loader gave us a value for secure_boot then we use that,
784 	 * otherwise we ask the BIOS.
785 	 */
786 	if (boot_params->secure_boot == efi_secureboot_mode_unset)
787 		boot_params->secure_boot = efi_get_secureboot();
788 
789 	/* Ask the firmware to clear memory on unclean shutdown */
790 	efi_enable_reset_attack_mitigation();
791 
792 	efi_random_get_seed();
793 
794 	efi_retrieve_tpm2_eventlog();
795 
796 	setup_graphics(boot_params);
797 
798 	setup_efi_pci(boot_params);
799 
800 	setup_quirks(boot_params);
801 
802 	status = exit_boot(boot_params, handle);
803 	if (status != EFI_SUCCESS) {
804 		efi_err("exit_boot() failed!\n");
805 		goto fail;
806 	}
807 
808 	return bzimage_addr;
809 fail:
810 	efi_err("efi_main() failed!\n");
811 
812 	efi_exit(handle, status);
813 }
814