1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * x86_64 specific EFI support functions
4 * Based on Extensible Firmware Interface Specification version 1.0
5 *
6 * Copyright (C) 2005-2008 Intel Co.
7 * Fenghua Yu <fenghua.yu@intel.com>
8 * Bibo Mao <bibo.mao@intel.com>
9 * Chandramouli Narayanan <mouli@linux.intel.com>
10 * Huang Ying <ying.huang@intel.com>
11 *
12 * Code to convert EFI to E820 map has been implemented in elilo bootloader
13 * based on a EFI patch by Edgar Hucek. Based on the E820 map, the page table
14 * is setup appropriately for EFI runtime code.
15 * - mouli 06/14/2007.
16 *
17 */
18
19 #define pr_fmt(fmt) "efi: " fmt
20
21 #include <linux/kernel.h>
22 #include <linux/init.h>
23 #include <linux/mm.h>
24 #include <linux/types.h>
25 #include <linux/spinlock.h>
26 #include <linux/memblock.h>
27 #include <linux/ioport.h>
28 #include <linux/mc146818rtc.h>
29 #include <linux/efi.h>
30 #include <linux/export.h>
31 #include <linux/uaccess.h>
32 #include <linux/io.h>
33 #include <linux/reboot.h>
34 #include <linux/slab.h>
35 #include <linux/ucs2_string.h>
36 #include <linux/mem_encrypt.h>
37 #include <linux/sched/task.h>
38
39 #include <asm/setup.h>
40 #include <asm/page.h>
41 #include <asm/e820/api.h>
42 #include <asm/pgtable.h>
43 #include <asm/tlbflush.h>
44 #include <asm/proto.h>
45 #include <asm/efi.h>
46 #include <asm/cacheflush.h>
47 #include <asm/fixmap.h>
48 #include <asm/realmode.h>
49 #include <asm/time.h>
50 #include <asm/pgalloc.h>
51
52 /*
53 * We allocate runtime services regions top-down, starting from -4G, i.e.
54 * 0xffff_ffff_0000_0000 and limit EFI VA mapping space to 64G.
55 */
56 static u64 efi_va = EFI_VA_START;
57
58 struct efi_scratch efi_scratch;
59
early_code_mapping_set_exec(int executable)60 static void __init early_code_mapping_set_exec(int executable)
61 {
62 efi_memory_desc_t *md;
63
64 if (!(__supported_pte_mask & _PAGE_NX))
65 return;
66
67 /* Make EFI service code area executable */
68 for_each_efi_memory_desc(md) {
69 if (md->type == EFI_RUNTIME_SERVICES_CODE ||
70 md->type == EFI_BOOT_SERVICES_CODE)
71 efi_set_executable(md, executable);
72 }
73 }
74
efi_call_phys_prolog(void)75 pgd_t * __init efi_call_phys_prolog(void)
76 {
77 unsigned long vaddr, addr_pgd, addr_p4d, addr_pud;
78 pgd_t *save_pgd, *pgd_k, *pgd_efi;
79 p4d_t *p4d, *p4d_k, *p4d_efi;
80 pud_t *pud;
81
82 int pgd;
83 int n_pgds, i, j;
84
85 if (!efi_enabled(EFI_OLD_MEMMAP)) {
86 efi_switch_mm(&efi_mm);
87 return efi_mm.pgd;
88 }
89
90 early_code_mapping_set_exec(1);
91
92 n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT), PGDIR_SIZE);
93 save_pgd = kmalloc_array(n_pgds, sizeof(*save_pgd), GFP_KERNEL);
94 if (!save_pgd)
95 return NULL;
96
97 /*
98 * Build 1:1 identity mapping for efi=old_map usage. Note that
99 * PAGE_OFFSET is PGDIR_SIZE aligned when KASLR is disabled, while
100 * it is PUD_SIZE ALIGNED with KASLR enabled. So for a given physical
101 * address X, the pud_index(X) != pud_index(__va(X)), we can only copy
102 * PUD entry of __va(X) to fill in pud entry of X to build 1:1 mapping.
103 * This means here we can only reuse the PMD tables of the direct mapping.
104 */
105 for (pgd = 0; pgd < n_pgds; pgd++) {
106 addr_pgd = (unsigned long)(pgd * PGDIR_SIZE);
107 vaddr = (unsigned long)__va(pgd * PGDIR_SIZE);
108 pgd_efi = pgd_offset_k(addr_pgd);
109 save_pgd[pgd] = *pgd_efi;
110
111 p4d = p4d_alloc(&init_mm, pgd_efi, addr_pgd);
112 if (!p4d) {
113 pr_err("Failed to allocate p4d table!\n");
114 goto out;
115 }
116
117 for (i = 0; i < PTRS_PER_P4D; i++) {
118 addr_p4d = addr_pgd + i * P4D_SIZE;
119 p4d_efi = p4d + p4d_index(addr_p4d);
120
121 pud = pud_alloc(&init_mm, p4d_efi, addr_p4d);
122 if (!pud) {
123 pr_err("Failed to allocate pud table!\n");
124 goto out;
125 }
126
127 for (j = 0; j < PTRS_PER_PUD; j++) {
128 addr_pud = addr_p4d + j * PUD_SIZE;
129
130 if (addr_pud > (max_pfn << PAGE_SHIFT))
131 break;
132
133 vaddr = (unsigned long)__va(addr_pud);
134
135 pgd_k = pgd_offset_k(vaddr);
136 p4d_k = p4d_offset(pgd_k, vaddr);
137 pud[j] = *pud_offset(p4d_k, vaddr);
138 }
139 }
140 pgd_offset_k(pgd * PGDIR_SIZE)->pgd &= ~_PAGE_NX;
141 }
142
143 __flush_tlb_all();
144 return save_pgd;
145 out:
146 efi_call_phys_epilog(save_pgd);
147 return NULL;
148 }
149
efi_call_phys_epilog(pgd_t * save_pgd)150 void __init efi_call_phys_epilog(pgd_t *save_pgd)
151 {
152 /*
153 * After the lock is released, the original page table is restored.
154 */
155 int pgd_idx, i;
156 int nr_pgds;
157 pgd_t *pgd;
158 p4d_t *p4d;
159 pud_t *pud;
160
161 if (!efi_enabled(EFI_OLD_MEMMAP)) {
162 efi_switch_mm(efi_scratch.prev_mm);
163 return;
164 }
165
166 nr_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT) , PGDIR_SIZE);
167
168 for (pgd_idx = 0; pgd_idx < nr_pgds; pgd_idx++) {
169 pgd = pgd_offset_k(pgd_idx * PGDIR_SIZE);
170 set_pgd(pgd_offset_k(pgd_idx * PGDIR_SIZE), save_pgd[pgd_idx]);
171
172 if (!pgd_present(*pgd))
173 continue;
174
175 for (i = 0; i < PTRS_PER_P4D; i++) {
176 p4d = p4d_offset(pgd,
177 pgd_idx * PGDIR_SIZE + i * P4D_SIZE);
178
179 if (!p4d_present(*p4d))
180 continue;
181
182 pud = (pud_t *)p4d_page_vaddr(*p4d);
183 pud_free(&init_mm, pud);
184 }
185
186 p4d = (p4d_t *)pgd_page_vaddr(*pgd);
187 p4d_free(&init_mm, p4d);
188 }
189
190 kfree(save_pgd);
191
192 __flush_tlb_all();
193 early_code_mapping_set_exec(0);
194 }
195
196 EXPORT_SYMBOL_GPL(efi_mm);
197
198 /*
199 * We need our own copy of the higher levels of the page tables
200 * because we want to avoid inserting EFI region mappings (EFI_VA_END
201 * to EFI_VA_START) into the standard kernel page tables. Everything
202 * else can be shared, see efi_sync_low_kernel_mappings().
203 *
204 * We don't want the pgd on the pgd_list and cannot use pgd_alloc() for the
205 * allocation.
206 */
efi_alloc_page_tables(void)207 int __init efi_alloc_page_tables(void)
208 {
209 pgd_t *pgd, *efi_pgd;
210 p4d_t *p4d;
211 pud_t *pud;
212 gfp_t gfp_mask;
213
214 if (efi_enabled(EFI_OLD_MEMMAP))
215 return 0;
216
217 gfp_mask = GFP_KERNEL | __GFP_ZERO;
218 efi_pgd = (pgd_t *)__get_free_pages(gfp_mask, PGD_ALLOCATION_ORDER);
219 if (!efi_pgd)
220 goto fail;
221
222 pgd = efi_pgd + pgd_index(EFI_VA_END);
223 p4d = p4d_alloc(&init_mm, pgd, EFI_VA_END);
224 if (!p4d)
225 goto free_pgd;
226
227 pud = pud_alloc(&init_mm, p4d, EFI_VA_END);
228 if (!pud)
229 goto free_p4d;
230
231 efi_mm.pgd = efi_pgd;
232 mm_init_cpumask(&efi_mm);
233 init_new_context(NULL, &efi_mm);
234
235 return 0;
236
237 free_p4d:
238 if (pgtable_l5_enabled())
239 free_page((unsigned long)pgd_page_vaddr(*pgd));
240 free_pgd:
241 free_pages((unsigned long)efi_pgd, PGD_ALLOCATION_ORDER);
242 fail:
243 return -ENOMEM;
244 }
245
246 /*
247 * Add low kernel mappings for passing arguments to EFI functions.
248 */
efi_sync_low_kernel_mappings(void)249 void efi_sync_low_kernel_mappings(void)
250 {
251 unsigned num_entries;
252 pgd_t *pgd_k, *pgd_efi;
253 p4d_t *p4d_k, *p4d_efi;
254 pud_t *pud_k, *pud_efi;
255 pgd_t *efi_pgd = efi_mm.pgd;
256
257 if (efi_enabled(EFI_OLD_MEMMAP))
258 return;
259
260 /*
261 * We can share all PGD entries apart from the one entry that
262 * covers the EFI runtime mapping space.
263 *
264 * Make sure the EFI runtime region mappings are guaranteed to
265 * only span a single PGD entry and that the entry also maps
266 * other important kernel regions.
267 */
268 MAYBE_BUILD_BUG_ON(pgd_index(EFI_VA_END) != pgd_index(MODULES_END));
269 MAYBE_BUILD_BUG_ON((EFI_VA_START & PGDIR_MASK) !=
270 (EFI_VA_END & PGDIR_MASK));
271
272 pgd_efi = efi_pgd + pgd_index(PAGE_OFFSET);
273 pgd_k = pgd_offset_k(PAGE_OFFSET);
274
275 num_entries = pgd_index(EFI_VA_END) - pgd_index(PAGE_OFFSET);
276 memcpy(pgd_efi, pgd_k, sizeof(pgd_t) * num_entries);
277
278 /*
279 * As with PGDs, we share all P4D entries apart from the one entry
280 * that covers the EFI runtime mapping space.
281 */
282 BUILD_BUG_ON(p4d_index(EFI_VA_END) != p4d_index(MODULES_END));
283 BUILD_BUG_ON((EFI_VA_START & P4D_MASK) != (EFI_VA_END & P4D_MASK));
284
285 pgd_efi = efi_pgd + pgd_index(EFI_VA_END);
286 pgd_k = pgd_offset_k(EFI_VA_END);
287 p4d_efi = p4d_offset(pgd_efi, 0);
288 p4d_k = p4d_offset(pgd_k, 0);
289
290 num_entries = p4d_index(EFI_VA_END);
291 memcpy(p4d_efi, p4d_k, sizeof(p4d_t) * num_entries);
292
293 /*
294 * We share all the PUD entries apart from those that map the
295 * EFI regions. Copy around them.
296 */
297 BUILD_BUG_ON((EFI_VA_START & ~PUD_MASK) != 0);
298 BUILD_BUG_ON((EFI_VA_END & ~PUD_MASK) != 0);
299
300 p4d_efi = p4d_offset(pgd_efi, EFI_VA_END);
301 p4d_k = p4d_offset(pgd_k, EFI_VA_END);
302 pud_efi = pud_offset(p4d_efi, 0);
303 pud_k = pud_offset(p4d_k, 0);
304
305 num_entries = pud_index(EFI_VA_END);
306 memcpy(pud_efi, pud_k, sizeof(pud_t) * num_entries);
307
308 pud_efi = pud_offset(p4d_efi, EFI_VA_START);
309 pud_k = pud_offset(p4d_k, EFI_VA_START);
310
311 num_entries = PTRS_PER_PUD - pud_index(EFI_VA_START);
312 memcpy(pud_efi, pud_k, sizeof(pud_t) * num_entries);
313 }
314
315 /*
316 * Wrapper for slow_virt_to_phys() that handles NULL addresses.
317 */
318 static inline phys_addr_t
virt_to_phys_or_null_size(void * va,unsigned long size)319 virt_to_phys_or_null_size(void *va, unsigned long size)
320 {
321 phys_addr_t pa;
322
323 if (!va)
324 return 0;
325
326 if (virt_addr_valid(va))
327 return virt_to_phys(va);
328
329 pa = slow_virt_to_phys(va);
330
331 /* check if the object crosses a page boundary */
332 if (WARN_ON((pa ^ (pa + size - 1)) & PAGE_MASK))
333 return 0;
334
335 return pa;
336 }
337
338 #define virt_to_phys_or_null(addr) \
339 virt_to_phys_or_null_size((addr), sizeof(*(addr)))
340
efi_setup_page_tables(unsigned long pa_memmap,unsigned num_pages)341 int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
342 {
343 unsigned long pfn, text, pf;
344 struct page *page;
345 unsigned npages;
346 pgd_t *pgd = efi_mm.pgd;
347
348 if (efi_enabled(EFI_OLD_MEMMAP))
349 return 0;
350
351 /*
352 * It can happen that the physical address of new_memmap lands in memory
353 * which is not mapped in the EFI page table. Therefore we need to go
354 * and ident-map those pages containing the map before calling
355 * phys_efi_set_virtual_address_map().
356 */
357 pfn = pa_memmap >> PAGE_SHIFT;
358 pf = _PAGE_NX | _PAGE_RW | _PAGE_ENC;
359 if (kernel_map_pages_in_pgd(pgd, pfn, pa_memmap, num_pages, pf)) {
360 pr_err("Error ident-mapping new memmap (0x%lx)!\n", pa_memmap);
361 return 1;
362 }
363
364 /*
365 * Certain firmware versions are way too sentimential and still believe
366 * they are exclusive and unquestionable owners of the first physical page,
367 * even though they explicitly mark it as EFI_CONVENTIONAL_MEMORY
368 * (but then write-access it later during SetVirtualAddressMap()).
369 *
370 * Create a 1:1 mapping for this page, to avoid triple faults during early
371 * boot with such firmware. We are free to hand this page to the BIOS,
372 * as trim_bios_range() will reserve the first page and isolate it away
373 * from memory allocators anyway.
374 */
375 pf = _PAGE_RW;
376 if (sev_active())
377 pf |= _PAGE_ENC;
378
379 if (kernel_map_pages_in_pgd(pgd, 0x0, 0x0, 1, pf)) {
380 pr_err("Failed to create 1:1 mapping for the first page!\n");
381 return 1;
382 }
383
384 /*
385 * When making calls to the firmware everything needs to be 1:1
386 * mapped and addressable with 32-bit pointers. Map the kernel
387 * text and allocate a new stack because we can't rely on the
388 * stack pointer being < 4GB.
389 */
390 if (!IS_ENABLED(CONFIG_EFI_MIXED) || efi_is_native())
391 return 0;
392
393 page = alloc_page(GFP_KERNEL|__GFP_DMA32);
394 if (!page) {
395 pr_err("Unable to allocate EFI runtime stack < 4GB\n");
396 return 1;
397 }
398
399 efi_scratch.phys_stack = page_to_phys(page + 1); /* stack grows down */
400
401 npages = (_etext - _text) >> PAGE_SHIFT;
402 text = __pa(_text);
403 pfn = text >> PAGE_SHIFT;
404
405 pf = _PAGE_RW | _PAGE_ENC;
406 if (kernel_map_pages_in_pgd(pgd, pfn, text, npages, pf)) {
407 pr_err("Failed to map kernel text 1:1\n");
408 return 1;
409 }
410
411 return 0;
412 }
413
__map_region(efi_memory_desc_t * md,u64 va)414 static void __init __map_region(efi_memory_desc_t *md, u64 va)
415 {
416 unsigned long flags = _PAGE_RW;
417 unsigned long pfn;
418 pgd_t *pgd = efi_mm.pgd;
419
420 if (!(md->attribute & EFI_MEMORY_WB))
421 flags |= _PAGE_PCD;
422
423 if (sev_active() && md->type != EFI_MEMORY_MAPPED_IO)
424 flags |= _PAGE_ENC;
425
426 pfn = md->phys_addr >> PAGE_SHIFT;
427 if (kernel_map_pages_in_pgd(pgd, pfn, va, md->num_pages, flags))
428 pr_warn("Error mapping PA 0x%llx -> VA 0x%llx!\n",
429 md->phys_addr, va);
430 }
431
efi_map_region(efi_memory_desc_t * md)432 void __init efi_map_region(efi_memory_desc_t *md)
433 {
434 unsigned long size = md->num_pages << PAGE_SHIFT;
435 u64 pa = md->phys_addr;
436
437 if (efi_enabled(EFI_OLD_MEMMAP))
438 return old_map_region(md);
439
440 /*
441 * Make sure the 1:1 mappings are present as a catch-all for b0rked
442 * firmware which doesn't update all internal pointers after switching
443 * to virtual mode and would otherwise crap on us.
444 */
445 __map_region(md, md->phys_addr);
446
447 /*
448 * Enforce the 1:1 mapping as the default virtual address when
449 * booting in EFI mixed mode, because even though we may be
450 * running a 64-bit kernel, the firmware may only be 32-bit.
451 */
452 if (!efi_is_native () && IS_ENABLED(CONFIG_EFI_MIXED)) {
453 md->virt_addr = md->phys_addr;
454 return;
455 }
456
457 efi_va -= size;
458
459 /* Is PA 2M-aligned? */
460 if (!(pa & (PMD_SIZE - 1))) {
461 efi_va &= PMD_MASK;
462 } else {
463 u64 pa_offset = pa & (PMD_SIZE - 1);
464 u64 prev_va = efi_va;
465
466 /* get us the same offset within this 2M page */
467 efi_va = (efi_va & PMD_MASK) + pa_offset;
468
469 if (efi_va > prev_va)
470 efi_va -= PMD_SIZE;
471 }
472
473 if (efi_va < EFI_VA_END) {
474 pr_warn(FW_WARN "VA address range overflow!\n");
475 return;
476 }
477
478 /* Do the VA map */
479 __map_region(md, efi_va);
480 md->virt_addr = efi_va;
481 }
482
483 /*
484 * kexec kernel will use efi_map_region_fixed to map efi runtime memory ranges.
485 * md->virt_addr is the original virtual address which had been mapped in kexec
486 * 1st kernel.
487 */
efi_map_region_fixed(efi_memory_desc_t * md)488 void __init efi_map_region_fixed(efi_memory_desc_t *md)
489 {
490 __map_region(md, md->phys_addr);
491 __map_region(md, md->virt_addr);
492 }
493
efi_ioremap(unsigned long phys_addr,unsigned long size,u32 type,u64 attribute)494 void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
495 u32 type, u64 attribute)
496 {
497 unsigned long last_map_pfn;
498
499 if (type == EFI_MEMORY_MAPPED_IO)
500 return ioremap(phys_addr, size);
501
502 last_map_pfn = init_memory_mapping(phys_addr, phys_addr + size);
503 if ((last_map_pfn << PAGE_SHIFT) < phys_addr + size) {
504 unsigned long top = last_map_pfn << PAGE_SHIFT;
505 efi_ioremap(top, size - (top - phys_addr), type, attribute);
506 }
507
508 if (!(attribute & EFI_MEMORY_WB))
509 efi_memory_uc((u64)(unsigned long)__va(phys_addr), size);
510
511 return (void __iomem *)__va(phys_addr);
512 }
513
parse_efi_setup(u64 phys_addr,u32 data_len)514 void __init parse_efi_setup(u64 phys_addr, u32 data_len)
515 {
516 efi_setup = phys_addr + sizeof(struct setup_data);
517 }
518
efi_update_mappings(efi_memory_desc_t * md,unsigned long pf)519 static int __init efi_update_mappings(efi_memory_desc_t *md, unsigned long pf)
520 {
521 unsigned long pfn;
522 pgd_t *pgd = efi_mm.pgd;
523 int err1, err2;
524
525 /* Update the 1:1 mapping */
526 pfn = md->phys_addr >> PAGE_SHIFT;
527 err1 = kernel_map_pages_in_pgd(pgd, pfn, md->phys_addr, md->num_pages, pf);
528 if (err1) {
529 pr_err("Error while updating 1:1 mapping PA 0x%llx -> VA 0x%llx!\n",
530 md->phys_addr, md->virt_addr);
531 }
532
533 err2 = kernel_map_pages_in_pgd(pgd, pfn, md->virt_addr, md->num_pages, pf);
534 if (err2) {
535 pr_err("Error while updating VA mapping PA 0x%llx -> VA 0x%llx!\n",
536 md->phys_addr, md->virt_addr);
537 }
538
539 return err1 || err2;
540 }
541
efi_update_mem_attr(struct mm_struct * mm,efi_memory_desc_t * md)542 static int __init efi_update_mem_attr(struct mm_struct *mm, efi_memory_desc_t *md)
543 {
544 unsigned long pf = 0;
545
546 if (md->attribute & EFI_MEMORY_XP)
547 pf |= _PAGE_NX;
548
549 if (!(md->attribute & EFI_MEMORY_RO))
550 pf |= _PAGE_RW;
551
552 if (sev_active())
553 pf |= _PAGE_ENC;
554
555 return efi_update_mappings(md, pf);
556 }
557
efi_runtime_update_mappings(void)558 void __init efi_runtime_update_mappings(void)
559 {
560 efi_memory_desc_t *md;
561
562 if (efi_enabled(EFI_OLD_MEMMAP)) {
563 if (__supported_pte_mask & _PAGE_NX)
564 runtime_code_page_mkexec();
565 return;
566 }
567
568 /*
569 * Use the EFI Memory Attribute Table for mapping permissions if it
570 * exists, since it is intended to supersede EFI_PROPERTIES_TABLE.
571 */
572 if (efi_enabled(EFI_MEM_ATTR)) {
573 efi_memattr_apply_permissions(NULL, efi_update_mem_attr);
574 return;
575 }
576
577 /*
578 * EFI_MEMORY_ATTRIBUTES_TABLE is intended to replace
579 * EFI_PROPERTIES_TABLE. So, use EFI_PROPERTIES_TABLE to update
580 * permissions only if EFI_MEMORY_ATTRIBUTES_TABLE is not
581 * published by the firmware. Even if we find a buggy implementation of
582 * EFI_MEMORY_ATTRIBUTES_TABLE, don't fall back to
583 * EFI_PROPERTIES_TABLE, because of the same reason.
584 */
585
586 if (!efi_enabled(EFI_NX_PE_DATA))
587 return;
588
589 for_each_efi_memory_desc(md) {
590 unsigned long pf = 0;
591
592 if (!(md->attribute & EFI_MEMORY_RUNTIME))
593 continue;
594
595 if (!(md->attribute & EFI_MEMORY_WB))
596 pf |= _PAGE_PCD;
597
598 if ((md->attribute & EFI_MEMORY_XP) ||
599 (md->type == EFI_RUNTIME_SERVICES_DATA))
600 pf |= _PAGE_NX;
601
602 if (!(md->attribute & EFI_MEMORY_RO) &&
603 (md->type != EFI_RUNTIME_SERVICES_CODE))
604 pf |= _PAGE_RW;
605
606 if (sev_active())
607 pf |= _PAGE_ENC;
608
609 efi_update_mappings(md, pf);
610 }
611 }
612
efi_dump_pagetable(void)613 void __init efi_dump_pagetable(void)
614 {
615 #ifdef CONFIG_EFI_PGT_DUMP
616 if (efi_enabled(EFI_OLD_MEMMAP))
617 ptdump_walk_pgd_level(NULL, swapper_pg_dir);
618 else
619 ptdump_walk_pgd_level(NULL, efi_mm.pgd);
620 #endif
621 }
622
623 /*
624 * Makes the calling thread switch to/from efi_mm context. Can be used
625 * in a kernel thread and user context. Preemption needs to remain disabled
626 * while the EFI-mm is borrowed. mmgrab()/mmdrop() is not used because the mm
627 * can not change under us.
628 * It should be ensured that there are no concurent calls to this function.
629 */
efi_switch_mm(struct mm_struct * mm)630 void efi_switch_mm(struct mm_struct *mm)
631 {
632 efi_scratch.prev_mm = current->active_mm;
633 current->active_mm = mm;
634 switch_mm(efi_scratch.prev_mm, mm, NULL);
635 }
636
637 #ifdef CONFIG_EFI_MIXED
638 extern efi_status_t efi64_thunk(u32, ...);
639
640 static DEFINE_SPINLOCK(efi_runtime_lock);
641
642 #define runtime_service32(func) \
643 ({ \
644 u32 table = (u32)(unsigned long)efi.systab; \
645 u32 *rt, *___f; \
646 \
647 rt = (u32 *)(table + offsetof(efi_system_table_32_t, runtime)); \
648 ___f = (u32 *)(*rt + offsetof(efi_runtime_services_32_t, func)); \
649 *___f; \
650 })
651
652 /*
653 * Switch to the EFI page tables early so that we can access the 1:1
654 * runtime services mappings which are not mapped in any other page
655 * tables. This function must be called before runtime_service32().
656 *
657 * Also, disable interrupts because the IDT points to 64-bit handlers,
658 * which aren't going to function correctly when we switch to 32-bit.
659 */
660 #define efi_thunk(f, ...) \
661 ({ \
662 efi_status_t __s; \
663 u32 __func; \
664 \
665 arch_efi_call_virt_setup(); \
666 \
667 __func = runtime_service32(f); \
668 __s = efi64_thunk(__func, __VA_ARGS__); \
669 \
670 arch_efi_call_virt_teardown(); \
671 \
672 __s; \
673 })
674
efi_thunk_set_virtual_address_map(void * phys_set_virtual_address_map,unsigned long memory_map_size,unsigned long descriptor_size,u32 descriptor_version,efi_memory_desc_t * virtual_map)675 efi_status_t efi_thunk_set_virtual_address_map(
676 void *phys_set_virtual_address_map,
677 unsigned long memory_map_size,
678 unsigned long descriptor_size,
679 u32 descriptor_version,
680 efi_memory_desc_t *virtual_map)
681 {
682 efi_status_t status;
683 unsigned long flags;
684 u32 func;
685
686 efi_sync_low_kernel_mappings();
687 local_irq_save(flags);
688
689 efi_switch_mm(&efi_mm);
690
691 func = (u32)(unsigned long)phys_set_virtual_address_map;
692 status = efi64_thunk(func, memory_map_size, descriptor_size,
693 descriptor_version, virtual_map);
694
695 efi_switch_mm(efi_scratch.prev_mm);
696 local_irq_restore(flags);
697
698 return status;
699 }
700
efi_thunk_get_time(efi_time_t * tm,efi_time_cap_t * tc)701 static efi_status_t efi_thunk_get_time(efi_time_t *tm, efi_time_cap_t *tc)
702 {
703 efi_status_t status;
704 u32 phys_tm, phys_tc;
705 unsigned long flags;
706
707 spin_lock(&rtc_lock);
708 spin_lock_irqsave(&efi_runtime_lock, flags);
709
710 phys_tm = virt_to_phys_or_null(tm);
711 phys_tc = virt_to_phys_or_null(tc);
712
713 status = efi_thunk(get_time, phys_tm, phys_tc);
714
715 spin_unlock_irqrestore(&efi_runtime_lock, flags);
716 spin_unlock(&rtc_lock);
717
718 return status;
719 }
720
efi_thunk_set_time(efi_time_t * tm)721 static efi_status_t efi_thunk_set_time(efi_time_t *tm)
722 {
723 efi_status_t status;
724 u32 phys_tm;
725 unsigned long flags;
726
727 spin_lock(&rtc_lock);
728 spin_lock_irqsave(&efi_runtime_lock, flags);
729
730 phys_tm = virt_to_phys_or_null(tm);
731
732 status = efi_thunk(set_time, phys_tm);
733
734 spin_unlock_irqrestore(&efi_runtime_lock, flags);
735 spin_unlock(&rtc_lock);
736
737 return status;
738 }
739
740 static efi_status_t
efi_thunk_get_wakeup_time(efi_bool_t * enabled,efi_bool_t * pending,efi_time_t * tm)741 efi_thunk_get_wakeup_time(efi_bool_t *enabled, efi_bool_t *pending,
742 efi_time_t *tm)
743 {
744 efi_status_t status;
745 u32 phys_enabled, phys_pending, phys_tm;
746 unsigned long flags;
747
748 spin_lock(&rtc_lock);
749 spin_lock_irqsave(&efi_runtime_lock, flags);
750
751 phys_enabled = virt_to_phys_or_null(enabled);
752 phys_pending = virt_to_phys_or_null(pending);
753 phys_tm = virt_to_phys_or_null(tm);
754
755 status = efi_thunk(get_wakeup_time, phys_enabled,
756 phys_pending, phys_tm);
757
758 spin_unlock_irqrestore(&efi_runtime_lock, flags);
759 spin_unlock(&rtc_lock);
760
761 return status;
762 }
763
764 static efi_status_t
efi_thunk_set_wakeup_time(efi_bool_t enabled,efi_time_t * tm)765 efi_thunk_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm)
766 {
767 efi_status_t status;
768 u32 phys_tm;
769 unsigned long flags;
770
771 spin_lock(&rtc_lock);
772 spin_lock_irqsave(&efi_runtime_lock, flags);
773
774 phys_tm = virt_to_phys_or_null(tm);
775
776 status = efi_thunk(set_wakeup_time, enabled, phys_tm);
777
778 spin_unlock_irqrestore(&efi_runtime_lock, flags);
779 spin_unlock(&rtc_lock);
780
781 return status;
782 }
783
efi_name_size(efi_char16_t * name)784 static unsigned long efi_name_size(efi_char16_t *name)
785 {
786 return ucs2_strsize(name, EFI_VAR_NAME_LEN) + 1;
787 }
788
789 static efi_status_t
efi_thunk_get_variable(efi_char16_t * name,efi_guid_t * vendor,u32 * attr,unsigned long * data_size,void * data)790 efi_thunk_get_variable(efi_char16_t *name, efi_guid_t *vendor,
791 u32 *attr, unsigned long *data_size, void *data)
792 {
793 u8 buf[24] __aligned(8);
794 efi_guid_t *vnd = PTR_ALIGN((efi_guid_t *)buf, sizeof(*vnd));
795 efi_status_t status;
796 u32 phys_name, phys_vendor, phys_attr;
797 u32 phys_data_size, phys_data;
798 unsigned long flags;
799
800 spin_lock_irqsave(&efi_runtime_lock, flags);
801
802 *vnd = *vendor;
803
804 phys_data_size = virt_to_phys_or_null(data_size);
805 phys_vendor = virt_to_phys_or_null(vnd);
806 phys_name = virt_to_phys_or_null_size(name, efi_name_size(name));
807 phys_attr = virt_to_phys_or_null(attr);
808 phys_data = virt_to_phys_or_null_size(data, *data_size);
809
810 if (!phys_name || (data && !phys_data))
811 status = EFI_INVALID_PARAMETER;
812 else
813 status = efi_thunk(get_variable, phys_name, phys_vendor,
814 phys_attr, phys_data_size, phys_data);
815
816 spin_unlock_irqrestore(&efi_runtime_lock, flags);
817
818 return status;
819 }
820
821 static efi_status_t
efi_thunk_set_variable(efi_char16_t * name,efi_guid_t * vendor,u32 attr,unsigned long data_size,void * data)822 efi_thunk_set_variable(efi_char16_t *name, efi_guid_t *vendor,
823 u32 attr, unsigned long data_size, void *data)
824 {
825 u8 buf[24] __aligned(8);
826 efi_guid_t *vnd = PTR_ALIGN((efi_guid_t *)buf, sizeof(*vnd));
827 u32 phys_name, phys_vendor, phys_data;
828 efi_status_t status;
829 unsigned long flags;
830
831 spin_lock_irqsave(&efi_runtime_lock, flags);
832
833 *vnd = *vendor;
834
835 phys_name = virt_to_phys_or_null_size(name, efi_name_size(name));
836 phys_vendor = virt_to_phys_or_null(vnd);
837 phys_data = virt_to_phys_or_null_size(data, data_size);
838
839 if (!phys_name || (data && !phys_data))
840 status = EFI_INVALID_PARAMETER;
841 else
842 status = efi_thunk(set_variable, phys_name, phys_vendor,
843 attr, data_size, phys_data);
844
845 spin_unlock_irqrestore(&efi_runtime_lock, flags);
846
847 return status;
848 }
849
850 static efi_status_t
efi_thunk_set_variable_nonblocking(efi_char16_t * name,efi_guid_t * vendor,u32 attr,unsigned long data_size,void * data)851 efi_thunk_set_variable_nonblocking(efi_char16_t *name, efi_guid_t *vendor,
852 u32 attr, unsigned long data_size,
853 void *data)
854 {
855 u8 buf[24] __aligned(8);
856 efi_guid_t *vnd = PTR_ALIGN((efi_guid_t *)buf, sizeof(*vnd));
857 u32 phys_name, phys_vendor, phys_data;
858 efi_status_t status;
859 unsigned long flags;
860
861 if (!spin_trylock_irqsave(&efi_runtime_lock, flags))
862 return EFI_NOT_READY;
863
864 *vnd = *vendor;
865
866 phys_name = virt_to_phys_or_null_size(name, efi_name_size(name));
867 phys_vendor = virt_to_phys_or_null(vnd);
868 phys_data = virt_to_phys_or_null_size(data, data_size);
869
870 if (!phys_name || (data && !phys_data))
871 status = EFI_INVALID_PARAMETER;
872 else
873 status = efi_thunk(set_variable, phys_name, phys_vendor,
874 attr, data_size, phys_data);
875
876 spin_unlock_irqrestore(&efi_runtime_lock, flags);
877
878 return status;
879 }
880
881 static efi_status_t
efi_thunk_get_next_variable(unsigned long * name_size,efi_char16_t * name,efi_guid_t * vendor)882 efi_thunk_get_next_variable(unsigned long *name_size,
883 efi_char16_t *name,
884 efi_guid_t *vendor)
885 {
886 u8 buf[24] __aligned(8);
887 efi_guid_t *vnd = PTR_ALIGN((efi_guid_t *)buf, sizeof(*vnd));
888 efi_status_t status;
889 u32 phys_name_size, phys_name, phys_vendor;
890 unsigned long flags;
891
892 spin_lock_irqsave(&efi_runtime_lock, flags);
893
894 *vnd = *vendor;
895
896 phys_name_size = virt_to_phys_or_null(name_size);
897 phys_vendor = virt_to_phys_or_null(vnd);
898 phys_name = virt_to_phys_or_null_size(name, *name_size);
899
900 if (!phys_name)
901 status = EFI_INVALID_PARAMETER;
902 else
903 status = efi_thunk(get_next_variable, phys_name_size,
904 phys_name, phys_vendor);
905
906 spin_unlock_irqrestore(&efi_runtime_lock, flags);
907
908 *vendor = *vnd;
909 return status;
910 }
911
912 static efi_status_t
efi_thunk_get_next_high_mono_count(u32 * count)913 efi_thunk_get_next_high_mono_count(u32 *count)
914 {
915 efi_status_t status;
916 u32 phys_count;
917 unsigned long flags;
918
919 spin_lock_irqsave(&efi_runtime_lock, flags);
920
921 phys_count = virt_to_phys_or_null(count);
922 status = efi_thunk(get_next_high_mono_count, phys_count);
923
924 spin_unlock_irqrestore(&efi_runtime_lock, flags);
925
926 return status;
927 }
928
929 static void
efi_thunk_reset_system(int reset_type,efi_status_t status,unsigned long data_size,efi_char16_t * data)930 efi_thunk_reset_system(int reset_type, efi_status_t status,
931 unsigned long data_size, efi_char16_t *data)
932 {
933 u32 phys_data;
934 unsigned long flags;
935
936 spin_lock_irqsave(&efi_runtime_lock, flags);
937
938 phys_data = virt_to_phys_or_null_size(data, data_size);
939
940 efi_thunk(reset_system, reset_type, status, data_size, phys_data);
941
942 spin_unlock_irqrestore(&efi_runtime_lock, flags);
943 }
944
945 static efi_status_t
efi_thunk_update_capsule(efi_capsule_header_t ** capsules,unsigned long count,unsigned long sg_list)946 efi_thunk_update_capsule(efi_capsule_header_t **capsules,
947 unsigned long count, unsigned long sg_list)
948 {
949 /*
950 * To properly support this function we would need to repackage
951 * 'capsules' because the firmware doesn't understand 64-bit
952 * pointers.
953 */
954 return EFI_UNSUPPORTED;
955 }
956
957 static efi_status_t
efi_thunk_query_variable_info(u32 attr,u64 * storage_space,u64 * remaining_space,u64 * max_variable_size)958 efi_thunk_query_variable_info(u32 attr, u64 *storage_space,
959 u64 *remaining_space,
960 u64 *max_variable_size)
961 {
962 efi_status_t status;
963 u32 phys_storage, phys_remaining, phys_max;
964 unsigned long flags;
965
966 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
967 return EFI_UNSUPPORTED;
968
969 spin_lock_irqsave(&efi_runtime_lock, flags);
970
971 phys_storage = virt_to_phys_or_null(storage_space);
972 phys_remaining = virt_to_phys_or_null(remaining_space);
973 phys_max = virt_to_phys_or_null(max_variable_size);
974
975 status = efi_thunk(query_variable_info, attr, phys_storage,
976 phys_remaining, phys_max);
977
978 spin_unlock_irqrestore(&efi_runtime_lock, flags);
979
980 return status;
981 }
982
983 static efi_status_t
efi_thunk_query_variable_info_nonblocking(u32 attr,u64 * storage_space,u64 * remaining_space,u64 * max_variable_size)984 efi_thunk_query_variable_info_nonblocking(u32 attr, u64 *storage_space,
985 u64 *remaining_space,
986 u64 *max_variable_size)
987 {
988 efi_status_t status;
989 u32 phys_storage, phys_remaining, phys_max;
990 unsigned long flags;
991
992 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
993 return EFI_UNSUPPORTED;
994
995 if (!spin_trylock_irqsave(&efi_runtime_lock, flags))
996 return EFI_NOT_READY;
997
998 phys_storage = virt_to_phys_or_null(storage_space);
999 phys_remaining = virt_to_phys_or_null(remaining_space);
1000 phys_max = virt_to_phys_or_null(max_variable_size);
1001
1002 status = efi_thunk(query_variable_info, attr, phys_storage,
1003 phys_remaining, phys_max);
1004
1005 spin_unlock_irqrestore(&efi_runtime_lock, flags);
1006
1007 return status;
1008 }
1009
1010 static efi_status_t
efi_thunk_query_capsule_caps(efi_capsule_header_t ** capsules,unsigned long count,u64 * max_size,int * reset_type)1011 efi_thunk_query_capsule_caps(efi_capsule_header_t **capsules,
1012 unsigned long count, u64 *max_size,
1013 int *reset_type)
1014 {
1015 /*
1016 * To properly support this function we would need to repackage
1017 * 'capsules' because the firmware doesn't understand 64-bit
1018 * pointers.
1019 */
1020 return EFI_UNSUPPORTED;
1021 }
1022
efi_thunk_runtime_setup(void)1023 void efi_thunk_runtime_setup(void)
1024 {
1025 efi.get_time = efi_thunk_get_time;
1026 efi.set_time = efi_thunk_set_time;
1027 efi.get_wakeup_time = efi_thunk_get_wakeup_time;
1028 efi.set_wakeup_time = efi_thunk_set_wakeup_time;
1029 efi.get_variable = efi_thunk_get_variable;
1030 efi.get_next_variable = efi_thunk_get_next_variable;
1031 efi.set_variable = efi_thunk_set_variable;
1032 efi.set_variable_nonblocking = efi_thunk_set_variable_nonblocking;
1033 efi.get_next_high_mono_count = efi_thunk_get_next_high_mono_count;
1034 efi.reset_system = efi_thunk_reset_system;
1035 efi.query_variable_info = efi_thunk_query_variable_info;
1036 efi.query_variable_info_nonblocking = efi_thunk_query_variable_info_nonblocking;
1037 efi.update_capsule = efi_thunk_update_capsule;
1038 efi.query_capsule_caps = efi_thunk_query_capsule_caps;
1039 }
1040 #endif /* CONFIG_EFI_MIXED */
1041