xref: /openbmc/linux/arch/x86/platform/efi/efi_64.c (revision 4da722ca)
1 /*
2  * x86_64 specific EFI support functions
3  * Based on Extensible Firmware Interface Specification version 1.0
4  *
5  * Copyright (C) 2005-2008 Intel Co.
6  *	Fenghua Yu <fenghua.yu@intel.com>
7  *	Bibo Mao <bibo.mao@intel.com>
8  *	Chandramouli Narayanan <mouli@linux.intel.com>
9  *	Huang Ying <ying.huang@intel.com>
10  *
11  * Code to convert EFI to E820 map has been implemented in elilo bootloader
12  * based on a EFI patch by Edgar Hucek. Based on the E820 map, the page table
13  * is setup appropriately for EFI runtime code.
14  * - mouli 06/14/2007.
15  *
16  */
17 
18 #define pr_fmt(fmt) "efi: " fmt
19 
20 #include <linux/kernel.h>
21 #include <linux/init.h>
22 #include <linux/mm.h>
23 #include <linux/types.h>
24 #include <linux/spinlock.h>
25 #include <linux/bootmem.h>
26 #include <linux/ioport.h>
27 #include <linux/init.h>
28 #include <linux/mc146818rtc.h>
29 #include <linux/efi.h>
30 #include <linux/uaccess.h>
31 #include <linux/io.h>
32 #include <linux/reboot.h>
33 #include <linux/slab.h>
34 #include <linux/ucs2_string.h>
35 
36 #include <asm/setup.h>
37 #include <asm/page.h>
38 #include <asm/e820/api.h>
39 #include <asm/pgtable.h>
40 #include <asm/tlbflush.h>
41 #include <asm/proto.h>
42 #include <asm/efi.h>
43 #include <asm/cacheflush.h>
44 #include <asm/fixmap.h>
45 #include <asm/realmode.h>
46 #include <asm/time.h>
47 #include <asm/pgalloc.h>
48 
49 /*
50  * We allocate runtime services regions top-down, starting from -4G, i.e.
51  * 0xffff_ffff_0000_0000 and limit EFI VA mapping space to 64G.
52  */
53 static u64 efi_va = EFI_VA_START;
54 
55 struct efi_scratch efi_scratch;
56 
57 static void __init early_code_mapping_set_exec(int executable)
58 {
59 	efi_memory_desc_t *md;
60 
61 	if (!(__supported_pte_mask & _PAGE_NX))
62 		return;
63 
64 	/* Make EFI service code area executable */
65 	for_each_efi_memory_desc(md) {
66 		if (md->type == EFI_RUNTIME_SERVICES_CODE ||
67 		    md->type == EFI_BOOT_SERVICES_CODE)
68 			efi_set_executable(md, executable);
69 	}
70 }
71 
72 pgd_t * __init efi_call_phys_prolog(void)
73 {
74 	unsigned long vaddr, addr_pgd, addr_p4d, addr_pud;
75 	pgd_t *save_pgd, *pgd_k, *pgd_efi;
76 	p4d_t *p4d, *p4d_k, *p4d_efi;
77 	pud_t *pud;
78 
79 	int pgd;
80 	int n_pgds, i, j;
81 
82 	if (!efi_enabled(EFI_OLD_MEMMAP)) {
83 		save_pgd = (pgd_t *)__read_cr3();
84 		write_cr3((unsigned long)efi_scratch.efi_pgt);
85 		goto out;
86 	}
87 
88 	early_code_mapping_set_exec(1);
89 
90 	n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT), PGDIR_SIZE);
91 	save_pgd = kmalloc_array(n_pgds, sizeof(*save_pgd), GFP_KERNEL);
92 
93 	/*
94 	 * Build 1:1 identity mapping for efi=old_map usage. Note that
95 	 * PAGE_OFFSET is PGDIR_SIZE aligned when KASLR is disabled, while
96 	 * it is PUD_SIZE ALIGNED with KASLR enabled. So for a given physical
97 	 * address X, the pud_index(X) != pud_index(__va(X)), we can only copy
98 	 * PUD entry of __va(X) to fill in pud entry of X to build 1:1 mapping.
99 	 * This means here we can only reuse the PMD tables of the direct mapping.
100 	 */
101 	for (pgd = 0; pgd < n_pgds; pgd++) {
102 		addr_pgd = (unsigned long)(pgd * PGDIR_SIZE);
103 		vaddr = (unsigned long)__va(pgd * PGDIR_SIZE);
104 		pgd_efi = pgd_offset_k(addr_pgd);
105 		save_pgd[pgd] = *pgd_efi;
106 
107 		p4d = p4d_alloc(&init_mm, pgd_efi, addr_pgd);
108 		if (!p4d) {
109 			pr_err("Failed to allocate p4d table!\n");
110 			goto out;
111 		}
112 
113 		for (i = 0; i < PTRS_PER_P4D; i++) {
114 			addr_p4d = addr_pgd + i * P4D_SIZE;
115 			p4d_efi = p4d + p4d_index(addr_p4d);
116 
117 			pud = pud_alloc(&init_mm, p4d_efi, addr_p4d);
118 			if (!pud) {
119 				pr_err("Failed to allocate pud table!\n");
120 				goto out;
121 			}
122 
123 			for (j = 0; j < PTRS_PER_PUD; j++) {
124 				addr_pud = addr_p4d + j * PUD_SIZE;
125 
126 				if (addr_pud > (max_pfn << PAGE_SHIFT))
127 					break;
128 
129 				vaddr = (unsigned long)__va(addr_pud);
130 
131 				pgd_k = pgd_offset_k(vaddr);
132 				p4d_k = p4d_offset(pgd_k, vaddr);
133 				pud[j] = *pud_offset(p4d_k, vaddr);
134 			}
135 		}
136 	}
137 out:
138 	__flush_tlb_all();
139 
140 	return save_pgd;
141 }
142 
143 void __init efi_call_phys_epilog(pgd_t *save_pgd)
144 {
145 	/*
146 	 * After the lock is released, the original page table is restored.
147 	 */
148 	int pgd_idx, i;
149 	int nr_pgds;
150 	pgd_t *pgd;
151 	p4d_t *p4d;
152 	pud_t *pud;
153 
154 	if (!efi_enabled(EFI_OLD_MEMMAP)) {
155 		write_cr3((unsigned long)save_pgd);
156 		__flush_tlb_all();
157 		return;
158 	}
159 
160 	nr_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT) , PGDIR_SIZE);
161 
162 	for (pgd_idx = 0; pgd_idx < nr_pgds; pgd_idx++) {
163 		pgd = pgd_offset_k(pgd_idx * PGDIR_SIZE);
164 		set_pgd(pgd_offset_k(pgd_idx * PGDIR_SIZE), save_pgd[pgd_idx]);
165 
166 		if (!(pgd_val(*pgd) & _PAGE_PRESENT))
167 			continue;
168 
169 		for (i = 0; i < PTRS_PER_P4D; i++) {
170 			p4d = p4d_offset(pgd,
171 					 pgd_idx * PGDIR_SIZE + i * P4D_SIZE);
172 
173 			if (!(p4d_val(*p4d) & _PAGE_PRESENT))
174 				continue;
175 
176 			pud = (pud_t *)p4d_page_vaddr(*p4d);
177 			pud_free(&init_mm, pud);
178 		}
179 
180 		p4d = (p4d_t *)pgd_page_vaddr(*pgd);
181 		p4d_free(&init_mm, p4d);
182 	}
183 
184 	kfree(save_pgd);
185 
186 	__flush_tlb_all();
187 	early_code_mapping_set_exec(0);
188 }
189 
190 static pgd_t *efi_pgd;
191 
192 /*
193  * We need our own copy of the higher levels of the page tables
194  * because we want to avoid inserting EFI region mappings (EFI_VA_END
195  * to EFI_VA_START) into the standard kernel page tables. Everything
196  * else can be shared, see efi_sync_low_kernel_mappings().
197  */
198 int __init efi_alloc_page_tables(void)
199 {
200 	pgd_t *pgd;
201 	p4d_t *p4d;
202 	pud_t *pud;
203 	gfp_t gfp_mask;
204 
205 	if (efi_enabled(EFI_OLD_MEMMAP))
206 		return 0;
207 
208 	gfp_mask = GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO;
209 	efi_pgd = (pgd_t *)__get_free_page(gfp_mask);
210 	if (!efi_pgd)
211 		return -ENOMEM;
212 
213 	pgd = efi_pgd + pgd_index(EFI_VA_END);
214 	p4d = p4d_alloc(&init_mm, pgd, EFI_VA_END);
215 	if (!p4d) {
216 		free_page((unsigned long)efi_pgd);
217 		return -ENOMEM;
218 	}
219 
220 	pud = pud_alloc(&init_mm, p4d, EFI_VA_END);
221 	if (!pud) {
222 		if (CONFIG_PGTABLE_LEVELS > 4)
223 			free_page((unsigned long) pgd_page_vaddr(*pgd));
224 		free_page((unsigned long)efi_pgd);
225 		return -ENOMEM;
226 	}
227 
228 	return 0;
229 }
230 
231 /*
232  * Add low kernel mappings for passing arguments to EFI functions.
233  */
234 void efi_sync_low_kernel_mappings(void)
235 {
236 	unsigned num_entries;
237 	pgd_t *pgd_k, *pgd_efi;
238 	p4d_t *p4d_k, *p4d_efi;
239 	pud_t *pud_k, *pud_efi;
240 
241 	if (efi_enabled(EFI_OLD_MEMMAP))
242 		return;
243 
244 	/*
245 	 * We can share all PGD entries apart from the one entry that
246 	 * covers the EFI runtime mapping space.
247 	 *
248 	 * Make sure the EFI runtime region mappings are guaranteed to
249 	 * only span a single PGD entry and that the entry also maps
250 	 * other important kernel regions.
251 	 */
252 	BUILD_BUG_ON(pgd_index(EFI_VA_END) != pgd_index(MODULES_END));
253 	BUILD_BUG_ON((EFI_VA_START & PGDIR_MASK) !=
254 			(EFI_VA_END & PGDIR_MASK));
255 
256 	pgd_efi = efi_pgd + pgd_index(PAGE_OFFSET);
257 	pgd_k = pgd_offset_k(PAGE_OFFSET);
258 
259 	num_entries = pgd_index(EFI_VA_END) - pgd_index(PAGE_OFFSET);
260 	memcpy(pgd_efi, pgd_k, sizeof(pgd_t) * num_entries);
261 
262 	/*
263 	 * As with PGDs, we share all P4D entries apart from the one entry
264 	 * that covers the EFI runtime mapping space.
265 	 */
266 	BUILD_BUG_ON(p4d_index(EFI_VA_END) != p4d_index(MODULES_END));
267 	BUILD_BUG_ON((EFI_VA_START & P4D_MASK) != (EFI_VA_END & P4D_MASK));
268 
269 	pgd_efi = efi_pgd + pgd_index(EFI_VA_END);
270 	pgd_k = pgd_offset_k(EFI_VA_END);
271 	p4d_efi = p4d_offset(pgd_efi, 0);
272 	p4d_k = p4d_offset(pgd_k, 0);
273 
274 	num_entries = p4d_index(EFI_VA_END);
275 	memcpy(p4d_efi, p4d_k, sizeof(p4d_t) * num_entries);
276 
277 	/*
278 	 * We share all the PUD entries apart from those that map the
279 	 * EFI regions. Copy around them.
280 	 */
281 	BUILD_BUG_ON((EFI_VA_START & ~PUD_MASK) != 0);
282 	BUILD_BUG_ON((EFI_VA_END & ~PUD_MASK) != 0);
283 
284 	p4d_efi = p4d_offset(pgd_efi, EFI_VA_END);
285 	p4d_k = p4d_offset(pgd_k, EFI_VA_END);
286 	pud_efi = pud_offset(p4d_efi, 0);
287 	pud_k = pud_offset(p4d_k, 0);
288 
289 	num_entries = pud_index(EFI_VA_END);
290 	memcpy(pud_efi, pud_k, sizeof(pud_t) * num_entries);
291 
292 	pud_efi = pud_offset(p4d_efi, EFI_VA_START);
293 	pud_k = pud_offset(p4d_k, EFI_VA_START);
294 
295 	num_entries = PTRS_PER_PUD - pud_index(EFI_VA_START);
296 	memcpy(pud_efi, pud_k, sizeof(pud_t) * num_entries);
297 }
298 
299 /*
300  * Wrapper for slow_virt_to_phys() that handles NULL addresses.
301  */
302 static inline phys_addr_t
303 virt_to_phys_or_null_size(void *va, unsigned long size)
304 {
305 	bool bad_size;
306 
307 	if (!va)
308 		return 0;
309 
310 	if (virt_addr_valid(va))
311 		return virt_to_phys(va);
312 
313 	/*
314 	 * A fully aligned variable on the stack is guaranteed not to
315 	 * cross a page bounary. Try to catch strings on the stack by
316 	 * checking that 'size' is a power of two.
317 	 */
318 	bad_size = size > PAGE_SIZE || !is_power_of_2(size);
319 
320 	WARN_ON(!IS_ALIGNED((unsigned long)va, size) || bad_size);
321 
322 	return slow_virt_to_phys(va);
323 }
324 
325 #define virt_to_phys_or_null(addr)				\
326 	virt_to_phys_or_null_size((addr), sizeof(*(addr)))
327 
328 int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
329 {
330 	unsigned long pfn, text;
331 	struct page *page;
332 	unsigned npages;
333 	pgd_t *pgd;
334 
335 	if (efi_enabled(EFI_OLD_MEMMAP))
336 		return 0;
337 
338 	efi_scratch.efi_pgt = (pgd_t *)__pa(efi_pgd);
339 	pgd = efi_pgd;
340 
341 	/*
342 	 * It can happen that the physical address of new_memmap lands in memory
343 	 * which is not mapped in the EFI page table. Therefore we need to go
344 	 * and ident-map those pages containing the map before calling
345 	 * phys_efi_set_virtual_address_map().
346 	 */
347 	pfn = pa_memmap >> PAGE_SHIFT;
348 	if (kernel_map_pages_in_pgd(pgd, pfn, pa_memmap, num_pages, _PAGE_NX | _PAGE_RW)) {
349 		pr_err("Error ident-mapping new memmap (0x%lx)!\n", pa_memmap);
350 		return 1;
351 	}
352 
353 	efi_scratch.use_pgd = true;
354 
355 	/*
356 	 * Certain firmware versions are way too sentimential and still believe
357 	 * they are exclusive and unquestionable owners of the first physical page,
358 	 * even though they explicitly mark it as EFI_CONVENTIONAL_MEMORY
359 	 * (but then write-access it later during SetVirtualAddressMap()).
360 	 *
361 	 * Create a 1:1 mapping for this page, to avoid triple faults during early
362 	 * boot with such firmware. We are free to hand this page to the BIOS,
363 	 * as trim_bios_range() will reserve the first page and isolate it away
364 	 * from memory allocators anyway.
365 	 */
366 	if (kernel_map_pages_in_pgd(pgd, 0x0, 0x0, 1, _PAGE_RW)) {
367 		pr_err("Failed to create 1:1 mapping for the first page!\n");
368 		return 1;
369 	}
370 
371 	/*
372 	 * When making calls to the firmware everything needs to be 1:1
373 	 * mapped and addressable with 32-bit pointers. Map the kernel
374 	 * text and allocate a new stack because we can't rely on the
375 	 * stack pointer being < 4GB.
376 	 */
377 	if (!IS_ENABLED(CONFIG_EFI_MIXED) || efi_is_native())
378 		return 0;
379 
380 	page = alloc_page(GFP_KERNEL|__GFP_DMA32);
381 	if (!page)
382 		panic("Unable to allocate EFI runtime stack < 4GB\n");
383 
384 	efi_scratch.phys_stack = virt_to_phys(page_address(page));
385 	efi_scratch.phys_stack += PAGE_SIZE; /* stack grows down */
386 
387 	npages = (_etext - _text) >> PAGE_SHIFT;
388 	text = __pa(_text);
389 	pfn = text >> PAGE_SHIFT;
390 
391 	if (kernel_map_pages_in_pgd(pgd, pfn, text, npages, _PAGE_RW)) {
392 		pr_err("Failed to map kernel text 1:1\n");
393 		return 1;
394 	}
395 
396 	return 0;
397 }
398 
399 static void __init __map_region(efi_memory_desc_t *md, u64 va)
400 {
401 	unsigned long flags = _PAGE_RW;
402 	unsigned long pfn;
403 	pgd_t *pgd = efi_pgd;
404 
405 	if (!(md->attribute & EFI_MEMORY_WB))
406 		flags |= _PAGE_PCD;
407 
408 	pfn = md->phys_addr >> PAGE_SHIFT;
409 	if (kernel_map_pages_in_pgd(pgd, pfn, va, md->num_pages, flags))
410 		pr_warn("Error mapping PA 0x%llx -> VA 0x%llx!\n",
411 			   md->phys_addr, va);
412 }
413 
414 void __init efi_map_region(efi_memory_desc_t *md)
415 {
416 	unsigned long size = md->num_pages << PAGE_SHIFT;
417 	u64 pa = md->phys_addr;
418 
419 	if (efi_enabled(EFI_OLD_MEMMAP))
420 		return old_map_region(md);
421 
422 	/*
423 	 * Make sure the 1:1 mappings are present as a catch-all for b0rked
424 	 * firmware which doesn't update all internal pointers after switching
425 	 * to virtual mode and would otherwise crap on us.
426 	 */
427 	__map_region(md, md->phys_addr);
428 
429 	/*
430 	 * Enforce the 1:1 mapping as the default virtual address when
431 	 * booting in EFI mixed mode, because even though we may be
432 	 * running a 64-bit kernel, the firmware may only be 32-bit.
433 	 */
434 	if (!efi_is_native () && IS_ENABLED(CONFIG_EFI_MIXED)) {
435 		md->virt_addr = md->phys_addr;
436 		return;
437 	}
438 
439 	efi_va -= size;
440 
441 	/* Is PA 2M-aligned? */
442 	if (!(pa & (PMD_SIZE - 1))) {
443 		efi_va &= PMD_MASK;
444 	} else {
445 		u64 pa_offset = pa & (PMD_SIZE - 1);
446 		u64 prev_va = efi_va;
447 
448 		/* get us the same offset within this 2M page */
449 		efi_va = (efi_va & PMD_MASK) + pa_offset;
450 
451 		if (efi_va > prev_va)
452 			efi_va -= PMD_SIZE;
453 	}
454 
455 	if (efi_va < EFI_VA_END) {
456 		pr_warn(FW_WARN "VA address range overflow!\n");
457 		return;
458 	}
459 
460 	/* Do the VA map */
461 	__map_region(md, efi_va);
462 	md->virt_addr = efi_va;
463 }
464 
465 /*
466  * kexec kernel will use efi_map_region_fixed to map efi runtime memory ranges.
467  * md->virt_addr is the original virtual address which had been mapped in kexec
468  * 1st kernel.
469  */
470 void __init efi_map_region_fixed(efi_memory_desc_t *md)
471 {
472 	__map_region(md, md->phys_addr);
473 	__map_region(md, md->virt_addr);
474 }
475 
476 void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
477 				 u32 type, u64 attribute)
478 {
479 	unsigned long last_map_pfn;
480 
481 	if (type == EFI_MEMORY_MAPPED_IO)
482 		return ioremap(phys_addr, size);
483 
484 	last_map_pfn = init_memory_mapping(phys_addr, phys_addr + size);
485 	if ((last_map_pfn << PAGE_SHIFT) < phys_addr + size) {
486 		unsigned long top = last_map_pfn << PAGE_SHIFT;
487 		efi_ioremap(top, size - (top - phys_addr), type, attribute);
488 	}
489 
490 	if (!(attribute & EFI_MEMORY_WB))
491 		efi_memory_uc((u64)(unsigned long)__va(phys_addr), size);
492 
493 	return (void __iomem *)__va(phys_addr);
494 }
495 
496 void __init parse_efi_setup(u64 phys_addr, u32 data_len)
497 {
498 	efi_setup = phys_addr + sizeof(struct setup_data);
499 }
500 
501 static int __init efi_update_mappings(efi_memory_desc_t *md, unsigned long pf)
502 {
503 	unsigned long pfn;
504 	pgd_t *pgd = efi_pgd;
505 	int err1, err2;
506 
507 	/* Update the 1:1 mapping */
508 	pfn = md->phys_addr >> PAGE_SHIFT;
509 	err1 = kernel_map_pages_in_pgd(pgd, pfn, md->phys_addr, md->num_pages, pf);
510 	if (err1) {
511 		pr_err("Error while updating 1:1 mapping PA 0x%llx -> VA 0x%llx!\n",
512 			   md->phys_addr, md->virt_addr);
513 	}
514 
515 	err2 = kernel_map_pages_in_pgd(pgd, pfn, md->virt_addr, md->num_pages, pf);
516 	if (err2) {
517 		pr_err("Error while updating VA mapping PA 0x%llx -> VA 0x%llx!\n",
518 			   md->phys_addr, md->virt_addr);
519 	}
520 
521 	return err1 || err2;
522 }
523 
524 static int __init efi_update_mem_attr(struct mm_struct *mm, efi_memory_desc_t *md)
525 {
526 	unsigned long pf = 0;
527 
528 	if (md->attribute & EFI_MEMORY_XP)
529 		pf |= _PAGE_NX;
530 
531 	if (!(md->attribute & EFI_MEMORY_RO))
532 		pf |= _PAGE_RW;
533 
534 	return efi_update_mappings(md, pf);
535 }
536 
537 void __init efi_runtime_update_mappings(void)
538 {
539 	efi_memory_desc_t *md;
540 
541 	if (efi_enabled(EFI_OLD_MEMMAP)) {
542 		if (__supported_pte_mask & _PAGE_NX)
543 			runtime_code_page_mkexec();
544 		return;
545 	}
546 
547 	/*
548 	 * Use the EFI Memory Attribute Table for mapping permissions if it
549 	 * exists, since it is intended to supersede EFI_PROPERTIES_TABLE.
550 	 */
551 	if (efi_enabled(EFI_MEM_ATTR)) {
552 		efi_memattr_apply_permissions(NULL, efi_update_mem_attr);
553 		return;
554 	}
555 
556 	/*
557 	 * EFI_MEMORY_ATTRIBUTES_TABLE is intended to replace
558 	 * EFI_PROPERTIES_TABLE. So, use EFI_PROPERTIES_TABLE to update
559 	 * permissions only if EFI_MEMORY_ATTRIBUTES_TABLE is not
560 	 * published by the firmware. Even if we find a buggy implementation of
561 	 * EFI_MEMORY_ATTRIBUTES_TABLE, don't fall back to
562 	 * EFI_PROPERTIES_TABLE, because of the same reason.
563 	 */
564 
565 	if (!efi_enabled(EFI_NX_PE_DATA))
566 		return;
567 
568 	for_each_efi_memory_desc(md) {
569 		unsigned long pf = 0;
570 
571 		if (!(md->attribute & EFI_MEMORY_RUNTIME))
572 			continue;
573 
574 		if (!(md->attribute & EFI_MEMORY_WB))
575 			pf |= _PAGE_PCD;
576 
577 		if ((md->attribute & EFI_MEMORY_XP) ||
578 			(md->type == EFI_RUNTIME_SERVICES_DATA))
579 			pf |= _PAGE_NX;
580 
581 		if (!(md->attribute & EFI_MEMORY_RO) &&
582 			(md->type != EFI_RUNTIME_SERVICES_CODE))
583 			pf |= _PAGE_RW;
584 
585 		efi_update_mappings(md, pf);
586 	}
587 }
588 
589 void __init efi_dump_pagetable(void)
590 {
591 #ifdef CONFIG_EFI_PGT_DUMP
592 	if (efi_enabled(EFI_OLD_MEMMAP))
593 		ptdump_walk_pgd_level(NULL, swapper_pg_dir);
594 	else
595 		ptdump_walk_pgd_level(NULL, efi_pgd);
596 #endif
597 }
598 
599 #ifdef CONFIG_EFI_MIXED
600 extern efi_status_t efi64_thunk(u32, ...);
601 
602 #define runtime_service32(func)						 \
603 ({									 \
604 	u32 table = (u32)(unsigned long)efi.systab;			 \
605 	u32 *rt, *___f;							 \
606 									 \
607 	rt = (u32 *)(table + offsetof(efi_system_table_32_t, runtime));	 \
608 	___f = (u32 *)(*rt + offsetof(efi_runtime_services_32_t, func)); \
609 	*___f;								 \
610 })
611 
612 /*
613  * Switch to the EFI page tables early so that we can access the 1:1
614  * runtime services mappings which are not mapped in any other page
615  * tables. This function must be called before runtime_service32().
616  *
617  * Also, disable interrupts because the IDT points to 64-bit handlers,
618  * which aren't going to function correctly when we switch to 32-bit.
619  */
620 #define efi_thunk(f, ...)						\
621 ({									\
622 	efi_status_t __s;						\
623 	unsigned long __flags;						\
624 	u32 __func;							\
625 									\
626 	local_irq_save(__flags);					\
627 	arch_efi_call_virt_setup();					\
628 									\
629 	__func = runtime_service32(f);					\
630 	__s = efi64_thunk(__func, __VA_ARGS__);				\
631 									\
632 	arch_efi_call_virt_teardown();					\
633 	local_irq_restore(__flags);					\
634 									\
635 	__s;								\
636 })
637 
638 efi_status_t efi_thunk_set_virtual_address_map(
639 	void *phys_set_virtual_address_map,
640 	unsigned long memory_map_size,
641 	unsigned long descriptor_size,
642 	u32 descriptor_version,
643 	efi_memory_desc_t *virtual_map)
644 {
645 	efi_status_t status;
646 	unsigned long flags;
647 	u32 func;
648 
649 	efi_sync_low_kernel_mappings();
650 	local_irq_save(flags);
651 
652 	efi_scratch.prev_cr3 = __read_cr3();
653 	write_cr3((unsigned long)efi_scratch.efi_pgt);
654 	__flush_tlb_all();
655 
656 	func = (u32)(unsigned long)phys_set_virtual_address_map;
657 	status = efi64_thunk(func, memory_map_size, descriptor_size,
658 			     descriptor_version, virtual_map);
659 
660 	write_cr3(efi_scratch.prev_cr3);
661 	__flush_tlb_all();
662 	local_irq_restore(flags);
663 
664 	return status;
665 }
666 
667 static efi_status_t efi_thunk_get_time(efi_time_t *tm, efi_time_cap_t *tc)
668 {
669 	efi_status_t status;
670 	u32 phys_tm, phys_tc;
671 
672 	spin_lock(&rtc_lock);
673 
674 	phys_tm = virt_to_phys_or_null(tm);
675 	phys_tc = virt_to_phys_or_null(tc);
676 
677 	status = efi_thunk(get_time, phys_tm, phys_tc);
678 
679 	spin_unlock(&rtc_lock);
680 
681 	return status;
682 }
683 
684 static efi_status_t efi_thunk_set_time(efi_time_t *tm)
685 {
686 	efi_status_t status;
687 	u32 phys_tm;
688 
689 	spin_lock(&rtc_lock);
690 
691 	phys_tm = virt_to_phys_or_null(tm);
692 
693 	status = efi_thunk(set_time, phys_tm);
694 
695 	spin_unlock(&rtc_lock);
696 
697 	return status;
698 }
699 
700 static efi_status_t
701 efi_thunk_get_wakeup_time(efi_bool_t *enabled, efi_bool_t *pending,
702 			  efi_time_t *tm)
703 {
704 	efi_status_t status;
705 	u32 phys_enabled, phys_pending, phys_tm;
706 
707 	spin_lock(&rtc_lock);
708 
709 	phys_enabled = virt_to_phys_or_null(enabled);
710 	phys_pending = virt_to_phys_or_null(pending);
711 	phys_tm = virt_to_phys_or_null(tm);
712 
713 	status = efi_thunk(get_wakeup_time, phys_enabled,
714 			     phys_pending, phys_tm);
715 
716 	spin_unlock(&rtc_lock);
717 
718 	return status;
719 }
720 
721 static efi_status_t
722 efi_thunk_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm)
723 {
724 	efi_status_t status;
725 	u32 phys_tm;
726 
727 	spin_lock(&rtc_lock);
728 
729 	phys_tm = virt_to_phys_or_null(tm);
730 
731 	status = efi_thunk(set_wakeup_time, enabled, phys_tm);
732 
733 	spin_unlock(&rtc_lock);
734 
735 	return status;
736 }
737 
738 static unsigned long efi_name_size(efi_char16_t *name)
739 {
740 	return ucs2_strsize(name, EFI_VAR_NAME_LEN) + 1;
741 }
742 
743 static efi_status_t
744 efi_thunk_get_variable(efi_char16_t *name, efi_guid_t *vendor,
745 		       u32 *attr, unsigned long *data_size, void *data)
746 {
747 	efi_status_t status;
748 	u32 phys_name, phys_vendor, phys_attr;
749 	u32 phys_data_size, phys_data;
750 
751 	phys_data_size = virt_to_phys_or_null(data_size);
752 	phys_vendor = virt_to_phys_or_null(vendor);
753 	phys_name = virt_to_phys_or_null_size(name, efi_name_size(name));
754 	phys_attr = virt_to_phys_or_null(attr);
755 	phys_data = virt_to_phys_or_null_size(data, *data_size);
756 
757 	status = efi_thunk(get_variable, phys_name, phys_vendor,
758 			   phys_attr, phys_data_size, phys_data);
759 
760 	return status;
761 }
762 
763 static efi_status_t
764 efi_thunk_set_variable(efi_char16_t *name, efi_guid_t *vendor,
765 		       u32 attr, unsigned long data_size, void *data)
766 {
767 	u32 phys_name, phys_vendor, phys_data;
768 	efi_status_t status;
769 
770 	phys_name = virt_to_phys_or_null_size(name, efi_name_size(name));
771 	phys_vendor = virt_to_phys_or_null(vendor);
772 	phys_data = virt_to_phys_or_null_size(data, data_size);
773 
774 	/* If data_size is > sizeof(u32) we've got problems */
775 	status = efi_thunk(set_variable, phys_name, phys_vendor,
776 			   attr, data_size, phys_data);
777 
778 	return status;
779 }
780 
781 static efi_status_t
782 efi_thunk_get_next_variable(unsigned long *name_size,
783 			    efi_char16_t *name,
784 			    efi_guid_t *vendor)
785 {
786 	efi_status_t status;
787 	u32 phys_name_size, phys_name, phys_vendor;
788 
789 	phys_name_size = virt_to_phys_or_null(name_size);
790 	phys_vendor = virt_to_phys_or_null(vendor);
791 	phys_name = virt_to_phys_or_null_size(name, *name_size);
792 
793 	status = efi_thunk(get_next_variable, phys_name_size,
794 			   phys_name, phys_vendor);
795 
796 	return status;
797 }
798 
799 static efi_status_t
800 efi_thunk_get_next_high_mono_count(u32 *count)
801 {
802 	efi_status_t status;
803 	u32 phys_count;
804 
805 	phys_count = virt_to_phys_or_null(count);
806 	status = efi_thunk(get_next_high_mono_count, phys_count);
807 
808 	return status;
809 }
810 
811 static void
812 efi_thunk_reset_system(int reset_type, efi_status_t status,
813 		       unsigned long data_size, efi_char16_t *data)
814 {
815 	u32 phys_data;
816 
817 	phys_data = virt_to_phys_or_null_size(data, data_size);
818 
819 	efi_thunk(reset_system, reset_type, status, data_size, phys_data);
820 }
821 
822 static efi_status_t
823 efi_thunk_update_capsule(efi_capsule_header_t **capsules,
824 			 unsigned long count, unsigned long sg_list)
825 {
826 	/*
827 	 * To properly support this function we would need to repackage
828 	 * 'capsules' because the firmware doesn't understand 64-bit
829 	 * pointers.
830 	 */
831 	return EFI_UNSUPPORTED;
832 }
833 
834 static efi_status_t
835 efi_thunk_query_variable_info(u32 attr, u64 *storage_space,
836 			      u64 *remaining_space,
837 			      u64 *max_variable_size)
838 {
839 	efi_status_t status;
840 	u32 phys_storage, phys_remaining, phys_max;
841 
842 	if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
843 		return EFI_UNSUPPORTED;
844 
845 	phys_storage = virt_to_phys_or_null(storage_space);
846 	phys_remaining = virt_to_phys_or_null(remaining_space);
847 	phys_max = virt_to_phys_or_null(max_variable_size);
848 
849 	status = efi_thunk(query_variable_info, attr, phys_storage,
850 			   phys_remaining, phys_max);
851 
852 	return status;
853 }
854 
855 static efi_status_t
856 efi_thunk_query_capsule_caps(efi_capsule_header_t **capsules,
857 			     unsigned long count, u64 *max_size,
858 			     int *reset_type)
859 {
860 	/*
861 	 * To properly support this function we would need to repackage
862 	 * 'capsules' because the firmware doesn't understand 64-bit
863 	 * pointers.
864 	 */
865 	return EFI_UNSUPPORTED;
866 }
867 
868 void efi_thunk_runtime_setup(void)
869 {
870 	efi.get_time = efi_thunk_get_time;
871 	efi.set_time = efi_thunk_set_time;
872 	efi.get_wakeup_time = efi_thunk_get_wakeup_time;
873 	efi.set_wakeup_time = efi_thunk_set_wakeup_time;
874 	efi.get_variable = efi_thunk_get_variable;
875 	efi.get_next_variable = efi_thunk_get_next_variable;
876 	efi.set_variable = efi_thunk_set_variable;
877 	efi.get_next_high_mono_count = efi_thunk_get_next_high_mono_count;
878 	efi.reset_system = efi_thunk_reset_system;
879 	efi.query_variable_info = efi_thunk_query_variable_info;
880 	efi.update_capsule = efi_thunk_update_capsule;
881 	efi.query_capsule_caps = efi_thunk_query_capsule_caps;
882 }
883 #endif /* CONFIG_EFI_MIXED */
884