1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Helper functions used by the EFI stub on multiple
4  * architectures. This should be #included by the EFI stub
5  * implementation files.
6  *
7  * Copyright 2011 Intel Corporation; author Matt Fleming
8  */
9 
10 #include <linux/stdarg.h>
11 
12 #include <linux/efi.h>
13 #include <linux/kernel.h>
14 #include <asm/efi.h>
15 #include <asm/setup.h>
16 
17 #include "efistub.h"
18 
19 bool efi_nochunk;
20 bool efi_nokaslr = !IS_ENABLED(CONFIG_RANDOMIZE_BASE);
21 bool efi_novamap;
22 
23 static bool efi_noinitrd;
24 static bool efi_nosoftreserve;
25 static bool efi_disable_pci_dma = IS_ENABLED(CONFIG_EFI_DISABLE_PCI_DMA);
26 
27 bool __pure __efi_soft_reserve_enabled(void)
28 {
29 	return !efi_nosoftreserve;
30 }
31 
32 /**
33  * efi_parse_options() - Parse EFI command line options
34  * @cmdline:	kernel command line
35  *
36  * Parse the ASCII string @cmdline for EFI options, denoted by the efi=
37  * option, e.g. efi=nochunk.
38  *
39  * It should be noted that efi= is parsed in two very different
40  * environments, first in the early boot environment of the EFI boot
41  * stub, and subsequently during the kernel boot.
42  *
43  * Return:	status code
44  */
45 efi_status_t efi_parse_options(char const *cmdline)
46 {
47 	size_t len;
48 	efi_status_t status;
49 	char *str, *buf;
50 
51 	if (!cmdline)
52 		return EFI_SUCCESS;
53 
54 	len = strnlen(cmdline, COMMAND_LINE_SIZE - 1) + 1;
55 	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, len, (void **)&buf);
56 	if (status != EFI_SUCCESS)
57 		return status;
58 
59 	memcpy(buf, cmdline, len - 1);
60 	buf[len - 1] = '\0';
61 	str = skip_spaces(buf);
62 
63 	while (*str) {
64 		char *param, *val;
65 
66 		str = next_arg(str, &param, &val);
67 		if (!val && !strcmp(param, "--"))
68 			break;
69 
70 		if (!strcmp(param, "nokaslr")) {
71 			efi_nokaslr = true;
72 		} else if (!strcmp(param, "quiet")) {
73 			efi_loglevel = CONSOLE_LOGLEVEL_QUIET;
74 		} else if (!strcmp(param, "noinitrd")) {
75 			efi_noinitrd = true;
76 		} else if (!strcmp(param, "efi") && val) {
77 			efi_nochunk = parse_option_str(val, "nochunk");
78 			efi_novamap |= parse_option_str(val, "novamap");
79 
80 			efi_nosoftreserve = IS_ENABLED(CONFIG_EFI_SOFT_RESERVE) &&
81 					    parse_option_str(val, "nosoftreserve");
82 
83 			if (parse_option_str(val, "disable_early_pci_dma"))
84 				efi_disable_pci_dma = true;
85 			if (parse_option_str(val, "no_disable_early_pci_dma"))
86 				efi_disable_pci_dma = false;
87 			if (parse_option_str(val, "debug"))
88 				efi_loglevel = CONSOLE_LOGLEVEL_DEBUG;
89 		} else if (!strcmp(param, "video") &&
90 			   val && strstarts(val, "efifb:")) {
91 			efi_parse_option_graphics(val + strlen("efifb:"));
92 		}
93 	}
94 	efi_bs_call(free_pool, buf);
95 	return EFI_SUCCESS;
96 }
97 
98 /*
99  * The EFI_LOAD_OPTION descriptor has the following layout:
100  *	u32 Attributes;
101  *	u16 FilePathListLength;
102  *	u16 Description[];
103  *	efi_device_path_protocol_t FilePathList[];
104  *	u8 OptionalData[];
105  *
106  * This function validates and unpacks the variable-size data fields.
107  */
108 static
109 bool efi_load_option_unpack(efi_load_option_unpacked_t *dest,
110 			    const efi_load_option_t *src, size_t size)
111 {
112 	const void *pos;
113 	u16 c;
114 	efi_device_path_protocol_t header;
115 	const efi_char16_t *description;
116 	const efi_device_path_protocol_t *file_path_list;
117 
118 	if (size < offsetof(efi_load_option_t, variable_data))
119 		return false;
120 	pos = src->variable_data;
121 	size -= offsetof(efi_load_option_t, variable_data);
122 
123 	if ((src->attributes & ~EFI_LOAD_OPTION_MASK) != 0)
124 		return false;
125 
126 	/* Scan description. */
127 	description = pos;
128 	do {
129 		if (size < sizeof(c))
130 			return false;
131 		c = *(const u16 *)pos;
132 		pos += sizeof(c);
133 		size -= sizeof(c);
134 	} while (c != L'\0');
135 
136 	/* Scan file_path_list. */
137 	file_path_list = pos;
138 	do {
139 		if (size < sizeof(header))
140 			return false;
141 		header = *(const efi_device_path_protocol_t *)pos;
142 		if (header.length < sizeof(header))
143 			return false;
144 		if (size < header.length)
145 			return false;
146 		pos += header.length;
147 		size -= header.length;
148 	} while ((header.type != EFI_DEV_END_PATH && header.type != EFI_DEV_END_PATH2) ||
149 		 (header.sub_type != EFI_DEV_END_ENTIRE));
150 	if (pos != (const void *)file_path_list + src->file_path_list_length)
151 		return false;
152 
153 	dest->attributes = src->attributes;
154 	dest->file_path_list_length = src->file_path_list_length;
155 	dest->description = description;
156 	dest->file_path_list = file_path_list;
157 	dest->optional_data_size = size;
158 	dest->optional_data = size ? pos : NULL;
159 
160 	return true;
161 }
162 
163 /*
164  * At least some versions of Dell firmware pass the entire contents of the
165  * Boot#### variable, i.e. the EFI_LOAD_OPTION descriptor, rather than just the
166  * OptionalData field.
167  *
168  * Detect this case and extract OptionalData.
169  */
170 void efi_apply_loadoptions_quirk(const void **load_options, u32 *load_options_size)
171 {
172 	const efi_load_option_t *load_option = *load_options;
173 	efi_load_option_unpacked_t load_option_unpacked;
174 
175 	if (!IS_ENABLED(CONFIG_X86))
176 		return;
177 	if (!load_option)
178 		return;
179 	if (*load_options_size < sizeof(*load_option))
180 		return;
181 	if ((load_option->attributes & ~EFI_LOAD_OPTION_BOOT_MASK) != 0)
182 		return;
183 
184 	if (!efi_load_option_unpack(&load_option_unpacked, load_option, *load_options_size))
185 		return;
186 
187 	efi_warn_once(FW_BUG "LoadOptions is an EFI_LOAD_OPTION descriptor\n");
188 	efi_warn_once(FW_BUG "Using OptionalData as a workaround\n");
189 
190 	*load_options = load_option_unpacked.optional_data;
191 	*load_options_size = load_option_unpacked.optional_data_size;
192 }
193 
194 enum efistub_event {
195 	EFISTUB_EVT_INITRD,
196 	EFISTUB_EVT_LOAD_OPTIONS,
197 	EFISTUB_EVT_COUNT,
198 };
199 
200 #define STR_WITH_SIZE(s)	sizeof(s), s
201 
202 static const struct {
203 	u32		pcr_index;
204 	u32		event_id;
205 	u32		event_data_len;
206 	u8		event_data[52];
207 } events[] = {
208 	[EFISTUB_EVT_INITRD] = {
209 		9,
210 		INITRD_EVENT_TAG_ID,
211 		STR_WITH_SIZE("Linux initrd")
212 	},
213 	[EFISTUB_EVT_LOAD_OPTIONS] = {
214 		9,
215 		LOAD_OPTIONS_EVENT_TAG_ID,
216 		STR_WITH_SIZE("LOADED_IMAGE::LoadOptions")
217 	},
218 };
219 
220 static efi_status_t efi_measure_tagged_event(unsigned long load_addr,
221 					     unsigned long load_size,
222 					     enum efistub_event event)
223 {
224 	efi_guid_t tcg2_guid = EFI_TCG2_PROTOCOL_GUID;
225 	efi_tcg2_protocol_t *tcg2 = NULL;
226 	efi_status_t status;
227 
228 	efi_bs_call(locate_protocol, &tcg2_guid, NULL, (void **)&tcg2);
229 	if (tcg2) {
230 		struct efi_measured_event {
231 			efi_tcg2_event_t	event_data;
232 			efi_tcg2_tagged_event_t tagged_event;
233 			u8			tagged_event_data[];
234 		} *evt;
235 		int size = sizeof(*evt) + events[event].event_data_len;
236 
237 		status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
238 				     (void **)&evt);
239 		if (status != EFI_SUCCESS)
240 			goto fail;
241 
242 		evt->event_data = (struct efi_tcg2_event){
243 			.event_size			= size,
244 			.event_header.header_size	= sizeof(evt->event_data.event_header),
245 			.event_header.header_version	= EFI_TCG2_EVENT_HEADER_VERSION,
246 			.event_header.pcr_index		= events[event].pcr_index,
247 			.event_header.event_type	= EV_EVENT_TAG,
248 		};
249 
250 		evt->tagged_event = (struct efi_tcg2_tagged_event){
251 			.tagged_event_id		= events[event].event_id,
252 			.tagged_event_data_size		= events[event].event_data_len,
253 		};
254 
255 		memcpy(evt->tagged_event_data, events[event].event_data,
256 		       events[event].event_data_len);
257 
258 		status = efi_call_proto(tcg2, hash_log_extend_event, 0,
259 					load_addr, load_size, &evt->event_data);
260 		efi_bs_call(free_pool, evt);
261 
262 		if (status != EFI_SUCCESS)
263 			goto fail;
264 		return EFI_SUCCESS;
265 	}
266 
267 	return EFI_UNSUPPORTED;
268 fail:
269 	efi_warn("Failed to measure data for event %d: 0x%lx\n", event, status);
270 	return status;
271 }
272 
273 /*
274  * Convert the unicode UEFI command line to ASCII to pass to kernel.
275  * Size of memory allocated return in *cmd_line_len.
276  * Returns NULL on error.
277  */
278 char *efi_convert_cmdline(efi_loaded_image_t *image, int *cmd_line_len)
279 {
280 	const efi_char16_t *options = efi_table_attr(image, load_options);
281 	u32 options_size = efi_table_attr(image, load_options_size);
282 	int options_bytes = 0, safe_options_bytes = 0;  /* UTF-8 bytes */
283 	unsigned long cmdline_addr = 0;
284 	const efi_char16_t *s2;
285 	bool in_quote = false;
286 	efi_status_t status;
287 	u32 options_chars;
288 
289 	if (options_size > 0)
290 		efi_measure_tagged_event((unsigned long)options, options_size,
291 					 EFISTUB_EVT_LOAD_OPTIONS);
292 
293 	efi_apply_loadoptions_quirk((const void **)&options, &options_size);
294 	options_chars = options_size / sizeof(efi_char16_t);
295 
296 	if (options) {
297 		s2 = options;
298 		while (options_bytes < COMMAND_LINE_SIZE && options_chars--) {
299 			efi_char16_t c = *s2++;
300 
301 			if (c < 0x80) {
302 				if (c == L'\0' || c == L'\n')
303 					break;
304 				if (c == L'"')
305 					in_quote = !in_quote;
306 				else if (!in_quote && isspace((char)c))
307 					safe_options_bytes = options_bytes;
308 
309 				options_bytes++;
310 				continue;
311 			}
312 
313 			/*
314 			 * Get the number of UTF-8 bytes corresponding to a
315 			 * UTF-16 character.
316 			 * The first part handles everything in the BMP.
317 			 */
318 			options_bytes += 2 + (c >= 0x800);
319 			/*
320 			 * Add one more byte for valid surrogate pairs. Invalid
321 			 * surrogates will be replaced with 0xfffd and take up
322 			 * only 3 bytes.
323 			 */
324 			if ((c & 0xfc00) == 0xd800) {
325 				/*
326 				 * If the very last word is a high surrogate,
327 				 * we must ignore it since we can't access the
328 				 * low surrogate.
329 				 */
330 				if (!options_chars) {
331 					options_bytes -= 3;
332 				} else if ((*s2 & 0xfc00) == 0xdc00) {
333 					options_bytes++;
334 					options_chars--;
335 					s2++;
336 				}
337 			}
338 		}
339 		if (options_bytes >= COMMAND_LINE_SIZE) {
340 			options_bytes = safe_options_bytes;
341 			efi_err("Command line is too long: truncated to %d bytes\n",
342 				options_bytes);
343 		}
344 	}
345 
346 	options_bytes++;	/* NUL termination */
347 
348 	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, options_bytes,
349 			     (void **)&cmdline_addr);
350 	if (status != EFI_SUCCESS)
351 		return NULL;
352 
353 	snprintf((char *)cmdline_addr, options_bytes, "%.*ls",
354 		 options_bytes - 1, options);
355 
356 	*cmd_line_len = options_bytes;
357 	return (char *)cmdline_addr;
358 }
359 
360 /**
361  * efi_exit_boot_services() - Exit boot services
362  * @handle:	handle of the exiting image
363  * @priv:	argument to be passed to @priv_func
364  * @priv_func:	function to process the memory map before exiting boot services
365  *
366  * Handle calling ExitBootServices according to the requirements set out by the
367  * spec.  Obtains the current memory map, and returns that info after calling
368  * ExitBootServices.  The client must specify a function to perform any
369  * processing of the memory map data prior to ExitBootServices.  A client
370  * specific structure may be passed to the function via priv.  The client
371  * function may be called multiple times.
372  *
373  * Return:	status code
374  */
375 efi_status_t efi_exit_boot_services(void *handle, void *priv,
376 				    efi_exit_boot_map_processing priv_func)
377 {
378 	struct efi_boot_memmap *map;
379 	efi_status_t status;
380 
381 	if (efi_disable_pci_dma)
382 		efi_pci_disable_bridge_busmaster();
383 
384 	status = efi_get_memory_map(&map, true);
385 	if (status != EFI_SUCCESS)
386 		return status;
387 
388 	status = priv_func(map, priv);
389 	if (status != EFI_SUCCESS) {
390 		efi_bs_call(free_pool, map);
391 		return status;
392 	}
393 
394 	status = efi_bs_call(exit_boot_services, handle, map->map_key);
395 
396 	if (status == EFI_INVALID_PARAMETER) {
397 		/*
398 		 * The memory map changed between efi_get_memory_map() and
399 		 * exit_boot_services().  Per the UEFI Spec v2.6, Section 6.4:
400 		 * EFI_BOOT_SERVICES.ExitBootServices we need to get the
401 		 * updated map, and try again.  The spec implies one retry
402 		 * should be sufficent, which is confirmed against the EDK2
403 		 * implementation.  Per the spec, we can only invoke
404 		 * get_memory_map() and exit_boot_services() - we cannot alloc
405 		 * so efi_get_memory_map() cannot be used, and we must reuse
406 		 * the buffer.  For all practical purposes, the headroom in the
407 		 * buffer should account for any changes in the map so the call
408 		 * to get_memory_map() is expected to succeed here.
409 		 */
410 		map->map_size = map->buff_size;
411 		status = efi_bs_call(get_memory_map,
412 				     &map->map_size,
413 				     &map->map,
414 				     &map->map_key,
415 				     &map->desc_size,
416 				     &map->desc_ver);
417 
418 		/* exit_boot_services() was called, thus cannot free */
419 		if (status != EFI_SUCCESS)
420 			return status;
421 
422 		status = priv_func(map, priv);
423 		/* exit_boot_services() was called, thus cannot free */
424 		if (status != EFI_SUCCESS)
425 			return status;
426 
427 		status = efi_bs_call(exit_boot_services, handle, map->map_key);
428 	}
429 
430 	return status;
431 }
432 
433 /**
434  * get_efi_config_table() - retrieve UEFI configuration table
435  * @guid:	GUID of the configuration table to be retrieved
436  * Return:	pointer to the configuration table or NULL
437  */
438 void *get_efi_config_table(efi_guid_t guid)
439 {
440 	unsigned long tables = efi_table_attr(efi_system_table, tables);
441 	int nr_tables = efi_table_attr(efi_system_table, nr_tables);
442 	int i;
443 
444 	for (i = 0; i < nr_tables; i++) {
445 		efi_config_table_t *t = (void *)tables;
446 
447 		if (efi_guidcmp(t->guid, guid) == 0)
448 			return efi_table_attr(t, table);
449 
450 		tables += efi_is_native() ? sizeof(efi_config_table_t)
451 					  : sizeof(efi_config_table_32_t);
452 	}
453 	return NULL;
454 }
455 
456 /*
457  * The LINUX_EFI_INITRD_MEDIA_GUID vendor media device path below provides a way
458  * for the firmware or bootloader to expose the initrd data directly to the stub
459  * via the trivial LoadFile2 protocol, which is defined in the UEFI spec, and is
460  * very easy to implement. It is a simple Linux initrd specific conduit between
461  * kernel and firmware, allowing us to put the EFI stub (being part of the
462  * kernel) in charge of where and when to load the initrd, while leaving it up
463  * to the firmware to decide whether it needs to expose its filesystem hierarchy
464  * via EFI protocols.
465  */
466 static const struct {
467 	struct efi_vendor_dev_path	vendor;
468 	struct efi_generic_dev_path	end;
469 } __packed initrd_dev_path = {
470 	{
471 		{
472 			EFI_DEV_MEDIA,
473 			EFI_DEV_MEDIA_VENDOR,
474 			sizeof(struct efi_vendor_dev_path),
475 		},
476 		LINUX_EFI_INITRD_MEDIA_GUID
477 	}, {
478 		EFI_DEV_END_PATH,
479 		EFI_DEV_END_ENTIRE,
480 		sizeof(struct efi_generic_dev_path)
481 	}
482 };
483 
484 /**
485  * efi_load_initrd_dev_path() - load the initrd from the Linux initrd device path
486  * @initrd:	pointer of struct to store the address where the initrd was loaded
487  *		and the size of the loaded initrd
488  * @max:	upper limit for the initrd memory allocation
489  *
490  * Return:
491  * * %EFI_SUCCESS if the initrd was loaded successfully, in which
492  *   case @load_addr and @load_size are assigned accordingly
493  * * %EFI_NOT_FOUND if no LoadFile2 protocol exists on the initrd device path
494  * * %EFI_OUT_OF_RESOURCES if memory allocation failed
495  * * %EFI_LOAD_ERROR in all other cases
496  */
497 static
498 efi_status_t efi_load_initrd_dev_path(struct linux_efi_initrd *initrd,
499 				      unsigned long max)
500 {
501 	efi_guid_t lf2_proto_guid = EFI_LOAD_FILE2_PROTOCOL_GUID;
502 	efi_device_path_protocol_t *dp;
503 	efi_load_file2_protocol_t *lf2;
504 	efi_handle_t handle;
505 	efi_status_t status;
506 
507 	dp = (efi_device_path_protocol_t *)&initrd_dev_path;
508 	status = efi_bs_call(locate_device_path, &lf2_proto_guid, &dp, &handle);
509 	if (status != EFI_SUCCESS)
510 		return status;
511 
512 	status = efi_bs_call(handle_protocol, handle, &lf2_proto_guid,
513 			     (void **)&lf2);
514 	if (status != EFI_SUCCESS)
515 		return status;
516 
517 	initrd->size = 0;
518 	status = efi_call_proto(lf2, load_file, dp, false, &initrd->size, NULL);
519 	if (status != EFI_BUFFER_TOO_SMALL)
520 		return EFI_LOAD_ERROR;
521 
522 	status = efi_allocate_pages(initrd->size, &initrd->base, max);
523 	if (status != EFI_SUCCESS)
524 		return status;
525 
526 	status = efi_call_proto(lf2, load_file, dp, false, &initrd->size,
527 				(void *)initrd->base);
528 	if (status != EFI_SUCCESS) {
529 		efi_free(initrd->size, initrd->base);
530 		return EFI_LOAD_ERROR;
531 	}
532 	return EFI_SUCCESS;
533 }
534 
535 static
536 efi_status_t efi_load_initrd_cmdline(efi_loaded_image_t *image,
537 				     struct linux_efi_initrd *initrd,
538 				     unsigned long soft_limit,
539 				     unsigned long hard_limit)
540 {
541 	if (image == NULL)
542 		return EFI_UNSUPPORTED;
543 
544 	return handle_cmdline_files(image, L"initrd=", sizeof(L"initrd=") - 2,
545 				    soft_limit, hard_limit,
546 				    &initrd->base, &initrd->size);
547 }
548 
549 /**
550  * efi_load_initrd() - Load initial RAM disk
551  * @image:	EFI loaded image protocol
552  * @soft_limit:	preferred address for loading the initrd
553  * @hard_limit:	upper limit address for loading the initrd
554  *
555  * Return:	status code
556  */
557 efi_status_t efi_load_initrd(efi_loaded_image_t *image,
558 			     unsigned long soft_limit,
559 			     unsigned long hard_limit,
560 			     const struct linux_efi_initrd **out)
561 {
562 	efi_guid_t tbl_guid = LINUX_EFI_INITRD_MEDIA_GUID;
563 	efi_status_t status = EFI_SUCCESS;
564 	struct linux_efi_initrd initrd, *tbl;
565 
566 	if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD) || efi_noinitrd)
567 		return EFI_SUCCESS;
568 
569 	status = efi_load_initrd_dev_path(&initrd, hard_limit);
570 	if (status == EFI_SUCCESS) {
571 		efi_info("Loaded initrd from LINUX_EFI_INITRD_MEDIA_GUID device path\n");
572 		if (initrd.size > 0 &&
573 		    efi_measure_tagged_event(initrd.base, initrd.size,
574 					     EFISTUB_EVT_INITRD) == EFI_SUCCESS)
575 			efi_info("Measured initrd data into PCR 9\n");
576 	} else if (status == EFI_NOT_FOUND) {
577 		status = efi_load_initrd_cmdline(image, &initrd, soft_limit,
578 						 hard_limit);
579 		/* command line loader disabled or no initrd= passed? */
580 		if (status == EFI_UNSUPPORTED || status == EFI_NOT_READY)
581 			return EFI_SUCCESS;
582 		if (status == EFI_SUCCESS)
583 			efi_info("Loaded initrd from command line option\n");
584 	}
585 	if (status != EFI_SUCCESS)
586 		goto failed;
587 
588 	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, sizeof(initrd),
589 			     (void **)&tbl);
590 	if (status != EFI_SUCCESS)
591 		goto free_initrd;
592 
593 	*tbl = initrd;
594 	status = efi_bs_call(install_configuration_table, &tbl_guid, tbl);
595 	if (status != EFI_SUCCESS)
596 		goto free_tbl;
597 
598 	if (out)
599 		*out = tbl;
600 	return EFI_SUCCESS;
601 
602 free_tbl:
603 	efi_bs_call(free_pool, tbl);
604 free_initrd:
605 	efi_free(initrd.size, initrd.base);
606 failed:
607 	efi_err("Failed to load initrd: 0x%lx\n", status);
608 	return status;
609 }
610 
611 /**
612  * efi_wait_for_key() - Wait for key stroke
613  * @usec:	number of microseconds to wait for key stroke
614  * @key:	key entered
615  *
616  * Wait for up to @usec microseconds for a key stroke.
617  *
618  * Return:	status code, EFI_SUCCESS if key received
619  */
620 efi_status_t efi_wait_for_key(unsigned long usec, efi_input_key_t *key)
621 {
622 	efi_event_t events[2], timer;
623 	unsigned long index;
624 	efi_simple_text_input_protocol_t *con_in;
625 	efi_status_t status;
626 
627 	con_in = efi_table_attr(efi_system_table, con_in);
628 	if (!con_in)
629 		return EFI_UNSUPPORTED;
630 	efi_set_event_at(events, 0, efi_table_attr(con_in, wait_for_key));
631 
632 	status = efi_bs_call(create_event, EFI_EVT_TIMER, 0, NULL, NULL, &timer);
633 	if (status != EFI_SUCCESS)
634 		return status;
635 
636 	status = efi_bs_call(set_timer, timer, EfiTimerRelative,
637 			     EFI_100NSEC_PER_USEC * usec);
638 	if (status != EFI_SUCCESS)
639 		return status;
640 	efi_set_event_at(events, 1, timer);
641 
642 	status = efi_bs_call(wait_for_event, 2, events, &index);
643 	if (status == EFI_SUCCESS) {
644 		if (index == 0)
645 			status = efi_call_proto(con_in, read_keystroke, key);
646 		else
647 			status = EFI_TIMEOUT;
648 	}
649 
650 	efi_bs_call(close_event, timer);
651 
652 	return status;
653 }
654 
655 /**
656  * efi_remap_image - Remap a loaded image with the appropriate permissions
657  *                   for code and data
658  *
659  * @image_base:	the base of the image in memory
660  * @alloc_size:	the size of the area in memory occupied by the image
661  * @code_size:	the size of the leading part of the image containing code
662  * 		and read-only data
663  *
664  * efi_remap_image() uses the EFI memory attribute protocol to remap the code
665  * region of the loaded image read-only/executable, and the remainder
666  * read-write/non-executable. The code region is assumed to start at the base
667  * of the image, and will therefore cover the PE/COFF header as well.
668  */
669 void efi_remap_image(unsigned long image_base, unsigned alloc_size,
670 		     unsigned long code_size)
671 {
672 	efi_guid_t guid = EFI_MEMORY_ATTRIBUTE_PROTOCOL_GUID;
673 	efi_memory_attribute_protocol_t *memattr;
674 	efi_status_t status;
675 	u64 attr;
676 
677 	/*
678 	 * If the firmware implements the EFI_MEMORY_ATTRIBUTE_PROTOCOL, let's
679 	 * invoke it to remap the text/rodata region of the decompressed image
680 	 * as read-only and the data/bss region as non-executable.
681 	 */
682 	status = efi_bs_call(locate_protocol, &guid, NULL, (void **)&memattr);
683 	if (status != EFI_SUCCESS)
684 		return;
685 
686 	// Get the current attributes for the entire region
687 	status = memattr->get_memory_attributes(memattr, image_base,
688 						alloc_size, &attr);
689 	if (status != EFI_SUCCESS) {
690 		efi_warn("Failed to retrieve memory attributes for image region: 0x%lx\n",
691 			 status);
692 		return;
693 	}
694 
695 	// Mark the code region as read-only
696 	status = memattr->set_memory_attributes(memattr, image_base, code_size,
697 						EFI_MEMORY_RO);
698 	if (status != EFI_SUCCESS) {
699 		efi_warn("Failed to remap code region read-only\n");
700 		return;
701 	}
702 
703 	// If the entire region was already mapped as non-exec, clear the
704 	// attribute from the code region. Otherwise, set it on the data
705 	// region.
706 	if (attr & EFI_MEMORY_XP) {
707 		status = memattr->clear_memory_attributes(memattr, image_base,
708 							  code_size,
709 							  EFI_MEMORY_XP);
710 		if (status != EFI_SUCCESS)
711 			efi_warn("Failed to remap code region executable\n");
712 	} else {
713 		status = memattr->set_memory_attributes(memattr,
714 							image_base + code_size,
715 							alloc_size - code_size,
716 							EFI_MEMORY_XP);
717 		if (status != EFI_SUCCESS)
718 			efi_warn("Failed to remap data region non-executable\n");
719 	}
720 }
721