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TOMOYO Linux Cross Reference
Linux/arch/x86/platform/efi/efi_64.c

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  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/bootmem.h>
 27 #include <linux/ioport.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 #include <linux/mem_encrypt.h>
 36 
 37 #include <asm/setup.h>
 38 #include <asm/page.h>
 39 #include <asm/e820/api.h>
 40 #include <asm/pgtable.h>
 41 #include <asm/tlbflush.h>
 42 #include <asm/proto.h>
 43 #include <asm/efi.h>
 44 #include <asm/cacheflush.h>
 45 #include <asm/fixmap.h>
 46 #include <asm/realmode.h>
 47 #include <asm/time.h>
 48 #include <asm/pgalloc.h>
 49 
 50 /*
 51  * We allocate runtime services regions top-down, starting from -4G, i.e.
 52  * 0xffff_ffff_0000_0000 and limit EFI VA mapping space to 64G.
 53  */
 54 static u64 efi_va = EFI_VA_START;
 55 
 56 struct efi_scratch efi_scratch;
 57 
 58 static void __init early_code_mapping_set_exec(int executable)
 59 {
 60         efi_memory_desc_t *md;
 61 
 62         if (!(__supported_pte_mask & _PAGE_NX))
 63                 return;
 64 
 65         /* Make EFI service code area executable */
 66         for_each_efi_memory_desc(md) {
 67                 if (md->type == EFI_RUNTIME_SERVICES_CODE ||
 68                     md->type == EFI_BOOT_SERVICES_CODE)
 69                         efi_set_executable(md, executable);
 70         }
 71 }
 72 
 73 pgd_t * __init efi_call_phys_prolog(void)
 74 {
 75         unsigned long vaddr, addr_pgd, addr_p4d, addr_pud;
 76         pgd_t *save_pgd, *pgd_k, *pgd_efi;
 77         p4d_t *p4d, *p4d_k, *p4d_efi;
 78         pud_t *pud;
 79 
 80         int pgd;
 81         int n_pgds, i, j;
 82 
 83         if (!efi_enabled(EFI_OLD_MEMMAP)) {
 84                 save_pgd = (pgd_t *)__read_cr3();
 85                 write_cr3((unsigned long)efi_scratch.efi_pgt);
 86                 goto out;
 87         }
 88 
 89         early_code_mapping_set_exec(1);
 90 
 91         n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT), PGDIR_SIZE);
 92         save_pgd = kmalloc_array(n_pgds, sizeof(*save_pgd), GFP_KERNEL);
 93 
 94         /*
 95          * Build 1:1 identity mapping for efi=old_map usage. Note that
 96          * PAGE_OFFSET is PGDIR_SIZE aligned when KASLR is disabled, while
 97          * it is PUD_SIZE ALIGNED with KASLR enabled. So for a given physical
 98          * address X, the pud_index(X) != pud_index(__va(X)), we can only copy
 99          * PUD entry of __va(X) to fill in pud entry of X to build 1:1 mapping.
100          * This means here we can only reuse the PMD tables of the direct mapping.
101          */
102         for (pgd = 0; pgd < n_pgds; pgd++) {
103                 addr_pgd = (unsigned long)(pgd * PGDIR_SIZE);
104                 vaddr = (unsigned long)__va(pgd * PGDIR_SIZE);
105                 pgd_efi = pgd_offset_k(addr_pgd);
106                 save_pgd[pgd] = *pgd_efi;
107 
108                 p4d = p4d_alloc(&init_mm, pgd_efi, addr_pgd);
109                 if (!p4d) {
110                         pr_err("Failed to allocate p4d table!\n");
111                         goto out;
112                 }
113 
114                 for (i = 0; i < PTRS_PER_P4D; i++) {
115                         addr_p4d = addr_pgd + i * P4D_SIZE;
116                         p4d_efi = p4d + p4d_index(addr_p4d);
117 
118                         pud = pud_alloc(&init_mm, p4d_efi, addr_p4d);
119                         if (!pud) {
120                                 pr_err("Failed to allocate pud table!\n");
121                                 goto out;
122                         }
123 
124                         for (j = 0; j < PTRS_PER_PUD; j++) {
125                                 addr_pud = addr_p4d + j * PUD_SIZE;
126 
127                                 if (addr_pud > (max_pfn << PAGE_SHIFT))
128                                         break;
129 
130                                 vaddr = (unsigned long)__va(addr_pud);
131 
132                                 pgd_k = pgd_offset_k(vaddr);
133                                 p4d_k = p4d_offset(pgd_k, vaddr);
134                                 pud[j] = *pud_offset(p4d_k, vaddr);
135                         }
136                 }
137                 pgd_offset_k(pgd * PGDIR_SIZE)->pgd &= ~_PAGE_NX;
138         }
139 
140 out:
141         __flush_tlb_all();
142 
143         return save_pgd;
144 }
145 
146 void __init efi_call_phys_epilog(pgd_t *save_pgd)
147 {
148         /*
149          * After the lock is released, the original page table is restored.
150          */
151         int pgd_idx, i;
152         int nr_pgds;
153         pgd_t *pgd;
154         p4d_t *p4d;
155         pud_t *pud;
156 
157         if (!efi_enabled(EFI_OLD_MEMMAP)) {
158                 write_cr3((unsigned long)save_pgd);
159                 __flush_tlb_all();
160                 return;
161         }
162 
163         nr_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT) , PGDIR_SIZE);
164 
165         for (pgd_idx = 0; pgd_idx < nr_pgds; pgd_idx++) {
166                 pgd = pgd_offset_k(pgd_idx * PGDIR_SIZE);
167                 set_pgd(pgd_offset_k(pgd_idx * PGDIR_SIZE), save_pgd[pgd_idx]);
168 
169                 if (!(pgd_val(*pgd) & _PAGE_PRESENT))
170                         continue;
171 
172                 for (i = 0; i < PTRS_PER_P4D; i++) {
173                         p4d = p4d_offset(pgd,
174                                          pgd_idx * PGDIR_SIZE + i * P4D_SIZE);
175 
176                         if (!(p4d_val(*p4d) & _PAGE_PRESENT))
177                                 continue;
178 
179                         pud = (pud_t *)p4d_page_vaddr(*p4d);
180                         pud_free(&init_mm, pud);
181                 }
182 
183                 p4d = (p4d_t *)pgd_page_vaddr(*pgd);
184                 p4d_free(&init_mm, p4d);
185         }
186 
187         kfree(save_pgd);
188 
189         __flush_tlb_all();
190         early_code_mapping_set_exec(0);
191 }
192 
193 static pgd_t *efi_pgd;
194 
195 /*
196  * We need our own copy of the higher levels of the page tables
197  * because we want to avoid inserting EFI region mappings (EFI_VA_END
198  * to EFI_VA_START) into the standard kernel page tables. Everything
199  * else can be shared, see efi_sync_low_kernel_mappings().
200  *
201  * We don't want the pgd on the pgd_list and cannot use pgd_alloc() for the
202  * allocation.
203  */
204 int __init efi_alloc_page_tables(void)
205 {
206         pgd_t *pgd;
207         p4d_t *p4d;
208         pud_t *pud;
209         gfp_t gfp_mask;
210 
211         if (efi_enabled(EFI_OLD_MEMMAP))
212                 return 0;
213 
214         gfp_mask = GFP_KERNEL | __GFP_ZERO;
215         efi_pgd = (pgd_t *)__get_free_pages(gfp_mask, PGD_ALLOCATION_ORDER);
216         if (!efi_pgd)
217                 return -ENOMEM;
218 
219         pgd = efi_pgd + pgd_index(EFI_VA_END);
220         p4d = p4d_alloc(&init_mm, pgd, EFI_VA_END);
221         if (!p4d) {
222                 free_page((unsigned long)efi_pgd);
223                 return -ENOMEM;
224         }
225 
226         pud = pud_alloc(&init_mm, p4d, EFI_VA_END);
227         if (!pud) {
228                 if (CONFIG_PGTABLE_LEVELS > 4)
229                         free_page((unsigned long) pgd_page_vaddr(*pgd));
230                 free_pages((unsigned long)efi_pgd, PGD_ALLOCATION_ORDER);
231                 return -ENOMEM;
232         }
233 
234         return 0;
235 }
236 
237 /*
238  * Add low kernel mappings for passing arguments to EFI functions.
239  */
240 void efi_sync_low_kernel_mappings(void)
241 {
242         unsigned num_entries;
243         pgd_t *pgd_k, *pgd_efi;
244         p4d_t *p4d_k, *p4d_efi;
245         pud_t *pud_k, *pud_efi;
246 
247         if (efi_enabled(EFI_OLD_MEMMAP))
248                 return;
249 
250         /*
251          * We can share all PGD entries apart from the one entry that
252          * covers the EFI runtime mapping space.
253          *
254          * Make sure the EFI runtime region mappings are guaranteed to
255          * only span a single PGD entry and that the entry also maps
256          * other important kernel regions.
257          */
258         BUILD_BUG_ON(pgd_index(EFI_VA_END) != pgd_index(MODULES_END));
259         BUILD_BUG_ON((EFI_VA_START & PGDIR_MASK) !=
260                         (EFI_VA_END & PGDIR_MASK));
261 
262         pgd_efi = efi_pgd + pgd_index(PAGE_OFFSET);
263         pgd_k = pgd_offset_k(PAGE_OFFSET);
264 
265         num_entries = pgd_index(EFI_VA_END) - pgd_index(PAGE_OFFSET);
266         memcpy(pgd_efi, pgd_k, sizeof(pgd_t) * num_entries);
267 
268         /*
269          * As with PGDs, we share all P4D entries apart from the one entry
270          * that covers the EFI runtime mapping space.
271          */
272         BUILD_BUG_ON(p4d_index(EFI_VA_END) != p4d_index(MODULES_END));
273         BUILD_BUG_ON((EFI_VA_START & P4D_MASK) != (EFI_VA_END & P4D_MASK));
274 
275         pgd_efi = efi_pgd + pgd_index(EFI_VA_END);
276         pgd_k = pgd_offset_k(EFI_VA_END);
277         p4d_efi = p4d_offset(pgd_efi, 0);
278         p4d_k = p4d_offset(pgd_k, 0);
279 
280         num_entries = p4d_index(EFI_VA_END);
281         memcpy(p4d_efi, p4d_k, sizeof(p4d_t) * num_entries);
282 
283         /*
284          * We share all the PUD entries apart from those that map the
285          * EFI regions. Copy around them.
286          */
287         BUILD_BUG_ON((EFI_VA_START & ~PUD_MASK) != 0);
288         BUILD_BUG_ON((EFI_VA_END & ~PUD_MASK) != 0);
289 
290         p4d_efi = p4d_offset(pgd_efi, EFI_VA_END);
291         p4d_k = p4d_offset(pgd_k, EFI_VA_END);
292         pud_efi = pud_offset(p4d_efi, 0);
293         pud_k = pud_offset(p4d_k, 0);
294 
295         num_entries = pud_index(EFI_VA_END);
296         memcpy(pud_efi, pud_k, sizeof(pud_t) * num_entries);
297 
298         pud_efi = pud_offset(p4d_efi, EFI_VA_START);
299         pud_k = pud_offset(p4d_k, EFI_VA_START);
300 
301         num_entries = PTRS_PER_PUD - pud_index(EFI_VA_START);
302         memcpy(pud_efi, pud_k, sizeof(pud_t) * num_entries);
303 }
304 
305 /*
306  * Wrapper for slow_virt_to_phys() that handles NULL addresses.
307  */
308 static inline phys_addr_t
309 virt_to_phys_or_null_size(void *va, unsigned long size)
310 {
311         bool bad_size;
312 
313         if (!va)
314                 return 0;
315 
316         if (virt_addr_valid(va))
317                 return virt_to_phys(va);
318 
319         /*
320          * A fully aligned variable on the stack is guaranteed not to
321          * cross a page bounary. Try to catch strings on the stack by
322          * checking that 'size' is a power of two.
323          */
324         bad_size = size > PAGE_SIZE || !is_power_of_2(size);
325 
326         WARN_ON(!IS_ALIGNED((unsigned long)va, size) || bad_size);
327 
328         return slow_virt_to_phys(va);
329 }
330 
331 #define virt_to_phys_or_null(addr)                              \
332         virt_to_phys_or_null_size((addr), sizeof(*(addr)))
333 
334 int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
335 {
336         unsigned long pfn, text, pf;
337         struct page *page;
338         unsigned npages;
339         pgd_t *pgd;
340 
341         if (efi_enabled(EFI_OLD_MEMMAP))
342                 return 0;
343 
344         /*
345          * Since the PGD is encrypted, set the encryption mask so that when
346          * this value is loaded into cr3 the PGD will be decrypted during
347          * the pagetable walk.
348          */
349         efi_scratch.efi_pgt = (pgd_t *)__sme_pa(efi_pgd);
350         pgd = efi_pgd;
351 
352         /*
353          * It can happen that the physical address of new_memmap lands in memory
354          * which is not mapped in the EFI page table. Therefore we need to go
355          * and ident-map those pages containing the map before calling
356          * phys_efi_set_virtual_address_map().
357          */
358         pfn = pa_memmap >> PAGE_SHIFT;
359         pf = _PAGE_NX | _PAGE_RW | _PAGE_ENC;
360         if (kernel_map_pages_in_pgd(pgd, pfn, pa_memmap, num_pages, pf)) {
361                 pr_err("Error ident-mapping new memmap (0x%lx)!\n", pa_memmap);
362                 return 1;
363         }
364 
365         efi_scratch.use_pgd = true;
366 
367         /*
368          * Certain firmware versions are way too sentimential and still believe
369          * they are exclusive and unquestionable owners of the first physical page,
370          * even though they explicitly mark it as EFI_CONVENTIONAL_MEMORY
371          * (but then write-access it later during SetVirtualAddressMap()).
372          *
373          * Create a 1:1 mapping for this page, to avoid triple faults during early
374          * boot with such firmware. We are free to hand this page to the BIOS,
375          * as trim_bios_range() will reserve the first page and isolate it away
376          * from memory allocators anyway.
377          */
378         pf = _PAGE_RW;
379         if (sev_active())
380                 pf |= _PAGE_ENC;
381 
382         if (kernel_map_pages_in_pgd(pgd, 0x0, 0x0, 1, pf)) {
383                 pr_err("Failed to create 1:1 mapping for the first page!\n");
384                 return 1;
385         }
386 
387         /*
388          * When making calls to the firmware everything needs to be 1:1
389          * mapped and addressable with 32-bit pointers. Map the kernel
390          * text and allocate a new stack because we can't rely on the
391          * stack pointer being < 4GB.
392          */
393         if (!IS_ENABLED(CONFIG_EFI_MIXED) || efi_is_native())
394                 return 0;
395 
396         page = alloc_page(GFP_KERNEL|__GFP_DMA32);
397         if (!page)
398                 panic("Unable to allocate EFI runtime stack < 4GB\n");
399 
400         efi_scratch.phys_stack = virt_to_phys(page_address(page));
401         efi_scratch.phys_stack += PAGE_SIZE; /* stack grows down */
402 
403         npages = (_etext - _text) >> PAGE_SHIFT;
404         text = __pa(_text);
405         pfn = text >> PAGE_SHIFT;
406 
407         pf = _PAGE_RW | _PAGE_ENC;
408         if (kernel_map_pages_in_pgd(pgd, pfn, text, npages, pf)) {
409                 pr_err("Failed to map kernel text 1:1\n");
410                 return 1;
411         }
412 
413         return 0;
414 }
415 
416 static void __init __map_region(efi_memory_desc_t *md, u64 va)
417 {
418         unsigned long flags = _PAGE_RW;
419         unsigned long pfn;
420         pgd_t *pgd = efi_pgd;
421 
422         if (!(md->attribute & EFI_MEMORY_WB))
423                 flags |= _PAGE_PCD;
424 
425         if (sev_active())
426                 flags |= _PAGE_ENC;
427 
428         pfn = md->phys_addr >> PAGE_SHIFT;
429         if (kernel_map_pages_in_pgd(pgd, pfn, va, md->num_pages, flags))
430                 pr_warn("Error mapping PA 0x%llx -> VA 0x%llx!\n",
431                            md->phys_addr, va);
432 }
433 
434 void __init efi_map_region(efi_memory_desc_t *md)
435 {
436         unsigned long size = md->num_pages << PAGE_SHIFT;
437         u64 pa = md->phys_addr;
438 
439         if (efi_enabled(EFI_OLD_MEMMAP))
440                 return old_map_region(md);
441 
442         /*
443          * Make sure the 1:1 mappings are present as a catch-all for b0rked
444          * firmware which doesn't update all internal pointers after switching
445          * to virtual mode and would otherwise crap on us.
446          */
447         __map_region(md, md->phys_addr);
448 
449         /*
450          * Enforce the 1:1 mapping as the default virtual address when
451          * booting in EFI mixed mode, because even though we may be
452          * running a 64-bit kernel, the firmware may only be 32-bit.
453          */
454         if (!efi_is_native () && IS_ENABLED(CONFIG_EFI_MIXED)) {
455                 md->virt_addr = md->phys_addr;
456                 return;
457         }
458 
459         efi_va -= size;
460 
461         /* Is PA 2M-aligned? */
462         if (!(pa & (PMD_SIZE - 1))) {
463                 efi_va &= PMD_MASK;
464         } else {
465                 u64 pa_offset = pa & (PMD_SIZE - 1);
466                 u64 prev_va = efi_va;
467 
468                 /* get us the same offset within this 2M page */
469                 efi_va = (efi_va & PMD_MASK) + pa_offset;
470 
471                 if (efi_va > prev_va)
472                         efi_va -= PMD_SIZE;
473         }
474 
475         if (efi_va < EFI_VA_END) {
476                 pr_warn(FW_WARN "VA address range overflow!\n");
477                 return;
478         }
479 
480         /* Do the VA map */
481         __map_region(md, efi_va);
482         md->virt_addr = efi_va;
483 }
484 
485 /*
486  * kexec kernel will use efi_map_region_fixed to map efi runtime memory ranges.
487  * md->virt_addr is the original virtual address which had been mapped in kexec
488  * 1st kernel.
489  */
490 void __init efi_map_region_fixed(efi_memory_desc_t *md)
491 {
492         __map_region(md, md->phys_addr);
493         __map_region(md, md->virt_addr);
494 }
495 
496 void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
497                                  u32 type, u64 attribute)
498 {
499         unsigned long last_map_pfn;
500 
501         if (type == EFI_MEMORY_MAPPED_IO)
502                 return ioremap(phys_addr, size);
503 
504         last_map_pfn = init_memory_mapping(phys_addr, phys_addr + size);
505         if ((last_map_pfn << PAGE_SHIFT) < phys_addr + size) {
506                 unsigned long top = last_map_pfn << PAGE_SHIFT;
507                 efi_ioremap(top, size - (top - phys_addr), type, attribute);
508         }
509 
510         if (!(attribute & EFI_MEMORY_WB))
511                 efi_memory_uc((u64)(unsigned long)__va(phys_addr), size);
512 
513         return (void __iomem *)__va(phys_addr);
514 }
515 
516 void __init parse_efi_setup(u64 phys_addr, u32 data_len)
517 {
518         efi_setup = phys_addr + sizeof(struct setup_data);
519 }
520 
521 static int __init efi_update_mappings(efi_memory_desc_t *md, unsigned long pf)
522 {
523         unsigned long pfn;
524         pgd_t *pgd = efi_pgd;
525         int err1, err2;
526 
527         /* Update the 1:1 mapping */
528         pfn = md->phys_addr >> PAGE_SHIFT;
529         err1 = kernel_map_pages_in_pgd(pgd, pfn, md->phys_addr, md->num_pages, pf);
530         if (err1) {
531                 pr_err("Error while updating 1:1 mapping PA 0x%llx -> VA 0x%llx!\n",
532                            md->phys_addr, md->virt_addr);
533         }
534 
535         err2 = kernel_map_pages_in_pgd(pgd, pfn, md->virt_addr, md->num_pages, pf);
536         if (err2) {
537                 pr_err("Error while updating VA mapping PA 0x%llx -> VA 0x%llx!\n",
538                            md->phys_addr, md->virt_addr);
539         }
540 
541         return err1 || err2;
542 }
543 
544 static int __init efi_update_mem_attr(struct mm_struct *mm, efi_memory_desc_t *md)
545 {
546         unsigned long pf = 0;
547 
548         if (md->attribute & EFI_MEMORY_XP)
549                 pf |= _PAGE_NX;
550 
551         if (!(md->attribute & EFI_MEMORY_RO))
552                 pf |= _PAGE_RW;
553 
554         if (sev_active())
555                 pf |= _PAGE_ENC;
556 
557         return efi_update_mappings(md, pf);
558 }
559 
560 void __init efi_runtime_update_mappings(void)
561 {
562         efi_memory_desc_t *md;
563 
564         if (efi_enabled(EFI_OLD_MEMMAP)) {
565                 if (__supported_pte_mask & _PAGE_NX)
566                         runtime_code_page_mkexec();
567                 return;
568         }
569 
570         /*
571          * Use the EFI Memory Attribute Table for mapping permissions if it
572          * exists, since it is intended to supersede EFI_PROPERTIES_TABLE.
573          */
574         if (efi_enabled(EFI_MEM_ATTR)) {
575                 efi_memattr_apply_permissions(NULL, efi_update_mem_attr);
576                 return;
577         }
578 
579         /*
580          * EFI_MEMORY_ATTRIBUTES_TABLE is intended to replace
581          * EFI_PROPERTIES_TABLE. So, use EFI_PROPERTIES_TABLE to update
582          * permissions only if EFI_MEMORY_ATTRIBUTES_TABLE is not
583          * published by the firmware. Even if we find a buggy implementation of
584          * EFI_MEMORY_ATTRIBUTES_TABLE, don't fall back to
585          * EFI_PROPERTIES_TABLE, because of the same reason.
586          */
587 
588         if (!efi_enabled(EFI_NX_PE_DATA))
589                 return;
590 
591         for_each_efi_memory_desc(md) {
592                 unsigned long pf = 0;
593 
594                 if (!(md->attribute & EFI_MEMORY_RUNTIME))
595                         continue;
596 
597                 if (!(md->attribute & EFI_MEMORY_WB))
598                         pf |= _PAGE_PCD;
599 
600                 if ((md->attribute & EFI_MEMORY_XP) ||
601                         (md->type == EFI_RUNTIME_SERVICES_DATA))
602                         pf |= _PAGE_NX;
603 
604                 if (!(md->attribute & EFI_MEMORY_RO) &&
605                         (md->type != EFI_RUNTIME_SERVICES_CODE))
606                         pf |= _PAGE_RW;
607 
608                 if (sev_active())
609                         pf |= _PAGE_ENC;
610 
611                 efi_update_mappings(md, pf);
612         }
613 }
614 
615 void __init efi_dump_pagetable(void)
616 {
617 #ifdef CONFIG_EFI_PGT_DUMP
618         if (efi_enabled(EFI_OLD_MEMMAP))
619                 ptdump_walk_pgd_level(NULL, swapper_pg_dir);
620         else
621                 ptdump_walk_pgd_level(NULL, efi_pgd);
622 #endif
623 }
624 
625 #ifdef CONFIG_EFI_MIXED
626 extern efi_status_t efi64_thunk(u32, ...);
627 
628 #define runtime_service32(func)                                          \
629 ({                                                                       \
630         u32 table = (u32)(unsigned long)efi.systab;                      \
631         u32 *rt, *___f;                                                  \
632                                                                          \
633         rt = (u32 *)(table + offsetof(efi_system_table_32_t, runtime));  \
634         ___f = (u32 *)(*rt + offsetof(efi_runtime_services_32_t, func)); \
635         *___f;                                                           \
636 })
637 
638 /*
639  * Switch to the EFI page tables early so that we can access the 1:1
640  * runtime services mappings which are not mapped in any other page
641  * tables. This function must be called before runtime_service32().
642  *
643  * Also, disable interrupts because the IDT points to 64-bit handlers,
644  * which aren't going to function correctly when we switch to 32-bit.
645  */
646 #define efi_thunk(f, ...)                                               \
647 ({                                                                      \
648         efi_status_t __s;                                               \
649         unsigned long __flags;                                          \
650         u32 __func;                                                     \
651                                                                         \
652         local_irq_save(__flags);                                        \
653         arch_efi_call_virt_setup();                                     \
654                                                                         \
655         __func = runtime_service32(f);                                  \
656         __s = efi64_thunk(__func, __VA_ARGS__);                         \
657                                                                         \
658         arch_efi_call_virt_teardown();                                  \
659         local_irq_restore(__flags);                                     \
660                                                                         \
661         __s;                                                            \
662 })
663 
664 efi_status_t efi_thunk_set_virtual_address_map(
665         void *phys_set_virtual_address_map,
666         unsigned long memory_map_size,
667         unsigned long descriptor_size,
668         u32 descriptor_version,
669         efi_memory_desc_t *virtual_map)
670 {
671         efi_status_t status;
672         unsigned long flags;
673         u32 func;
674 
675         efi_sync_low_kernel_mappings();
676         local_irq_save(flags);
677 
678         efi_scratch.prev_cr3 = __read_cr3();
679         write_cr3((unsigned long)efi_scratch.efi_pgt);
680         __flush_tlb_all();
681 
682         func = (u32)(unsigned long)phys_set_virtual_address_map;
683         status = efi64_thunk(func, memory_map_size, descriptor_size,
684                              descriptor_version, virtual_map);
685 
686         write_cr3(efi_scratch.prev_cr3);
687         __flush_tlb_all();
688         local_irq_restore(flags);
689 
690         return status;
691 }
692 
693 static efi_status_t efi_thunk_get_time(efi_time_t *tm, efi_time_cap_t *tc)
694 {
695         efi_status_t status;
696         u32 phys_tm, phys_tc;
697 
698         spin_lock(&rtc_lock);
699 
700         phys_tm = virt_to_phys_or_null(tm);
701         phys_tc = virt_to_phys_or_null(tc);
702 
703         status = efi_thunk(get_time, phys_tm, phys_tc);
704 
705         spin_unlock(&rtc_lock);
706 
707         return status;
708 }
709 
710 static efi_status_t efi_thunk_set_time(efi_time_t *tm)
711 {
712         efi_status_t status;
713         u32 phys_tm;
714 
715         spin_lock(&rtc_lock);
716 
717         phys_tm = virt_to_phys_or_null(tm);
718 
719         status = efi_thunk(set_time, phys_tm);
720 
721         spin_unlock(&rtc_lock);
722 
723         return status;
724 }
725 
726 static efi_status_t
727 efi_thunk_get_wakeup_time(efi_bool_t *enabled, efi_bool_t *pending,
728                           efi_time_t *tm)
729 {
730         efi_status_t status;
731         u32 phys_enabled, phys_pending, phys_tm;
732 
733         spin_lock(&rtc_lock);
734 
735         phys_enabled = virt_to_phys_or_null(enabled);
736         phys_pending = virt_to_phys_or_null(pending);
737         phys_tm = virt_to_phys_or_null(tm);
738 
739         status = efi_thunk(get_wakeup_time, phys_enabled,
740                              phys_pending, phys_tm);
741 
742         spin_unlock(&rtc_lock);
743 
744         return status;
745 }
746 
747 static efi_status_t
748 efi_thunk_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm)
749 {
750         efi_status_t status;
751         u32 phys_tm;
752 
753         spin_lock(&rtc_lock);
754 
755         phys_tm = virt_to_phys_or_null(tm);
756 
757         status = efi_thunk(set_wakeup_time, enabled, phys_tm);
758 
759         spin_unlock(&rtc_lock);
760 
761         return status;
762 }
763 
764 static unsigned long efi_name_size(efi_char16_t *name)
765 {
766         return ucs2_strsize(name, EFI_VAR_NAME_LEN) + 1;
767 }
768 
769 static efi_status_t
770 efi_thunk_get_variable(efi_char16_t *name, efi_guid_t *vendor,
771                        u32 *attr, unsigned long *data_size, void *data)
772 {
773         efi_status_t status;
774         u32 phys_name, phys_vendor, phys_attr;
775         u32 phys_data_size, phys_data;
776 
777         phys_data_size = virt_to_phys_or_null(data_size);
778         phys_vendor = virt_to_phys_or_null(vendor);
779         phys_name = virt_to_phys_or_null_size(name, efi_name_size(name));
780         phys_attr = virt_to_phys_or_null(attr);
781         phys_data = virt_to_phys_or_null_size(data, *data_size);
782 
783         status = efi_thunk(get_variable, phys_name, phys_vendor,
784                            phys_attr, phys_data_size, phys_data);
785 
786         return status;
787 }
788 
789 static efi_status_t
790 efi_thunk_set_variable(efi_char16_t *name, efi_guid_t *vendor,
791                        u32 attr, unsigned long data_size, void *data)
792 {
793         u32 phys_name, phys_vendor, phys_data;
794         efi_status_t status;
795 
796         phys_name = virt_to_phys_or_null_size(name, efi_name_size(name));
797         phys_vendor = virt_to_phys_or_null(vendor);
798         phys_data = virt_to_phys_or_null_size(data, data_size);
799 
800         /* If data_size is > sizeof(u32) we've got problems */
801         status = efi_thunk(set_variable, phys_name, phys_vendor,
802                            attr, data_size, phys_data);
803 
804         return status;
805 }
806 
807 static efi_status_t
808 efi_thunk_get_next_variable(unsigned long *name_size,
809                             efi_char16_t *name,
810                             efi_guid_t *vendor)
811 {
812         efi_status_t status;
813         u32 phys_name_size, phys_name, phys_vendor;
814 
815         phys_name_size = virt_to_phys_or_null(name_size);
816         phys_vendor = virt_to_phys_or_null(vendor);
817         phys_name = virt_to_phys_or_null_size(name, *name_size);
818 
819         status = efi_thunk(get_next_variable, phys_name_size,
820                            phys_name, phys_vendor);
821 
822         return status;
823 }
824 
825 static efi_status_t
826 efi_thunk_get_next_high_mono_count(u32 *count)
827 {
828         efi_status_t status;
829         u32 phys_count;
830 
831         phys_count = virt_to_phys_or_null(count);
832         status = efi_thunk(get_next_high_mono_count, phys_count);
833 
834         return status;
835 }
836 
837 static void
838 efi_thunk_reset_system(int reset_type, efi_status_t status,
839                        unsigned long data_size, efi_char16_t *data)
840 {
841         u32 phys_data;
842 
843         phys_data = virt_to_phys_or_null_size(data, data_size);
844 
845         efi_thunk(reset_system, reset_type, status, data_size, phys_data);
846 }
847 
848 static efi_status_t
849 efi_thunk_update_capsule(efi_capsule_header_t **capsules,
850                          unsigned long count, unsigned long sg_list)
851 {
852         /*
853          * To properly support this function we would need to repackage
854          * 'capsules' because the firmware doesn't understand 64-bit
855          * pointers.
856          */
857         return EFI_UNSUPPORTED;
858 }
859 
860 static efi_status_t
861 efi_thunk_query_variable_info(u32 attr, u64 *storage_space,
862                               u64 *remaining_space,
863                               u64 *max_variable_size)
864 {
865         efi_status_t status;
866         u32 phys_storage, phys_remaining, phys_max;
867 
868         if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
869                 return EFI_UNSUPPORTED;
870 
871         phys_storage = virt_to_phys_or_null(storage_space);
872         phys_remaining = virt_to_phys_or_null(remaining_space);
873         phys_max = virt_to_phys_or_null(max_variable_size);
874 
875         status = efi_thunk(query_variable_info, attr, phys_storage,
876                            phys_remaining, phys_max);
877 
878         return status;
879 }
880 
881 static efi_status_t
882 efi_thunk_query_capsule_caps(efi_capsule_header_t **capsules,
883                              unsigned long count, u64 *max_size,
884                              int *reset_type)
885 {
886         /*
887          * To properly support this function we would need to repackage
888          * 'capsules' because the firmware doesn't understand 64-bit
889          * pointers.
890          */
891         return EFI_UNSUPPORTED;
892 }
893 
894 void efi_thunk_runtime_setup(void)
895 {
896         efi.get_time = efi_thunk_get_time;
897         efi.set_time = efi_thunk_set_time;
898         efi.get_wakeup_time = efi_thunk_get_wakeup_time;
899         efi.set_wakeup_time = efi_thunk_set_wakeup_time;
900         efi.get_variable = efi_thunk_get_variable;
901         efi.get_next_variable = efi_thunk_get_next_variable;
902         efi.set_variable = efi_thunk_set_variable;
903         efi.get_next_high_mono_count = efi_thunk_get_next_high_mono_count;
904         efi.reset_system = efi_thunk_reset_system;
905         efi.query_variable_info = efi_thunk_query_variable_info;
906         efi.update_capsule = efi_thunk_update_capsule;
907         efi.query_capsule_caps = efi_thunk_query_capsule_caps;
908 }
909 #endif /* CONFIG_EFI_MIXED */
910 

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