arch/x86/platform/efi/efi_64.c

   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/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
  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
  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 NULL;
  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
  95         /*
  96          * Build 1:1 identity mapping for efi=old_map usage. Note that
  97          * PAGE_OFFSET is PGDIR_SIZE aligned when KASLR is disabled, while
  98          * it is PUD_SIZE ALIGNED with KASLR enabled. So for a given physical
  99          * address X, the pud_index(X) != pud_index(__va(X)), we can only copy
 100          * PUD entry of __va(X) to fill in pud entry of X to build 1:1 mapping.
 101          * This means here we can only reuse the PMD tables of the direct mapping.
 102          */
 103         for (pgd = 0; pgd < n_pgds; pgd++) {
 104                 addr_pgd = (unsigned long)(pgd * PGDIR_SIZE);
 105                 vaddr = (unsigned long)__va(pgd * PGDIR_SIZE);
 106                 pgd_efi = pgd_offset_k(addr_pgd);
 107                 save_pgd[pgd] = *pgd_efi;
 108
 109                 p4d = p4d_alloc(&init_mm, pgd_efi, addr_pgd);
 110                 if (!p4d) {
 111                         pr_err("Failed to allocate p4d table!\n");
 112                         goto out;
 113                 }
 114
 115                 for (i = 0; i < PTRS_PER_P4D; i++) {
 116                         addr_p4d = addr_pgd + i * P4D_SIZE;
 117                         p4d_efi = p4d + p4d_index(addr_p4d);
 118
 119                         pud = pud_alloc(&init_mm, p4d_efi, addr_p4d);
 120                         if (!pud) {
 121                                 pr_err("Failed to allocate pud table!\n");
 122                                 goto out;
 123                         }
 124
 125                         for (j = 0; j < PTRS_PER_PUD; j++) {
 126                                 addr_pud = addr_p4d + j * PUD_SIZE;
 127
 128                                 if (addr_pud > (max_pfn << PAGE_SHIFT))
 129                                         break;
 130
 131                                 vaddr = (unsigned long)__va(addr_pud);
 132
 133                                 pgd_k = pgd_offset_k(vaddr);
 134                                 p4d_k = p4d_offset(pgd_k, vaddr);
 135                                 pud[j] = *pud_offset(p4d_k, vaddr);
 136                         }
 137                 }
 138                 pgd_offset_k(pgd * PGDIR_SIZE)->pgd &= ~_PAGE_NX;
 139         }
 140
 141 out:
 142         __flush_tlb_all();
 143
 144         return save_pgd;
 145 }
 146
 147 void __init efi_call_phys_epilog(pgd_t *save_pgd)
 148 {
 149         /*
 150          * After the lock is released, the original page table is restored.
 151          */
 152         int pgd_idx, i;
 153         int nr_pgds;
 154         pgd_t *pgd;
 155         p4d_t *p4d;
 156         pud_t *pud;
 157
 158         if (!efi_enabled(EFI_OLD_MEMMAP)) {
 159                 efi_switch_mm(efi_scratch.prev_mm);
 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_present(*pgd))
 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_present(*p4d))
 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 EXPORT_SYMBOL_GPL(efi_mm);
 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, *efi_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 (pgtable_l5_enabled())
 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         efi_mm.pgd = efi_pgd;
 235         mm_init_cpumask(&efi_mm);
 236         init_new_context(NULL, &efi_mm);
 237
 238         return 0;
 239 }
 240
 241 /*
 242  * Add low kernel mappings for passing arguments to EFI functions.
 243  */
 244 void efi_sync_low_kernel_mappings(void)
 245 {
 246         unsigned num_entries;
 247         pgd_t *pgd_k, *pgd_efi;
 248         p4d_t *p4d_k, *p4d_efi;
 249         pud_t *pud_k, *pud_efi;
 250         pgd_t *efi_pgd = efi_mm.pgd;
 251
 252         if (efi_enabled(EFI_OLD_MEMMAP))
 253                 return;
 254
 255         /*
 256          * We can share all PGD entries apart from the one entry that
 257          * covers the EFI runtime mapping space.
 258          *
 259          * Make sure the EFI runtime region mappings are guaranteed to
 260          * only span a single PGD entry and that the entry also maps
 261          * other important kernel regions.
 262          */
 263         MAYBE_BUILD_BUG_ON(pgd_index(EFI_VA_END) != pgd_index(MODULES_END));
 264         MAYBE_BUILD_BUG_ON((EFI_VA_START & PGDIR_MASK) !=
 265                         (EFI_VA_END & PGDIR_MASK));
 266
 267         pgd_efi = efi_pgd + pgd_index(PAGE_OFFSET);
 268         pgd_k = pgd_offset_k(PAGE_OFFSET);
 269
 270         num_entries = pgd_index(EFI_VA_END) - pgd_index(PAGE_OFFSET);
 271         memcpy(pgd_efi, pgd_k, sizeof(pgd_t) * num_entries);
 272
 273         /*
 274          * As with PGDs, we share all P4D entries apart from the one entry
 275          * that covers the EFI runtime mapping space.
 276          */
 277         BUILD_BUG_ON(p4d_index(EFI_VA_END) != p4d_index(MODULES_END));
 278         BUILD_BUG_ON((EFI_VA_START & P4D_MASK) != (EFI_VA_END & P4D_MASK));
 279
 280         pgd_efi = efi_pgd + pgd_index(EFI_VA_END);
 281         pgd_k = pgd_offset_k(EFI_VA_END);
 282         p4d_efi = p4d_offset(pgd_efi, 0);
 283         p4d_k = p4d_offset(pgd_k, 0);
 284
 285         num_entries = p4d_index(EFI_VA_END);
 286         memcpy(p4d_efi, p4d_k, sizeof(p4d_t) * num_entries);
 287
 288         /*
 289          * We share all the PUD entries apart from those that map the
 290          * EFI regions. Copy around them.
 291          */
 292         BUILD_BUG_ON((EFI_VA_START & ~PUD_MASK) != 0);
 293         BUILD_BUG_ON((EFI_VA_END & ~PUD_MASK) != 0);
 294
 295         p4d_efi = p4d_offset(pgd_efi, EFI_VA_END);
 296         p4d_k = p4d_offset(pgd_k, EFI_VA_END);
 297         pud_efi = pud_offset(p4d_efi, 0);
 298         pud_k = pud_offset(p4d_k, 0);
 299
 300         num_entries = pud_index(EFI_VA_END);
 301         memcpy(pud_efi, pud_k, sizeof(pud_t) * num_entries);
 302
 303         pud_efi = pud_offset(p4d_efi, EFI_VA_START);
 304         pud_k = pud_offset(p4d_k, EFI_VA_START);
 305
 306         num_entries = PTRS_PER_PUD - pud_index(EFI_VA_START);
 307         memcpy(pud_efi, pud_k, sizeof(pud_t) * num_entries);
 308 }
 309
 310 /*
 311  * Wrapper for slow_virt_to_phys() that handles NULL addresses.
 312  */
 313 static inline phys_addr_t
 314 virt_to_phys_or_null_size(void *va, unsigned long size)
 315 {
 316         bool bad_size;
 317
 318         if (!va)
 319                 return 0;
 320
 321         if (virt_addr_valid(va))
 322                 return virt_to_phys(va);
 323
 324         /*
 325          * A fully aligned variable on the stack is guaranteed not to
 326          * cross a page bounary. Try to catch strings on the stack by
 327          * checking that 'size' is a power of two.
 328          */
 329         bad_size = size > PAGE_SIZE || !is_power_of_2(size);
 330
 331         WARN_ON(!IS_ALIGNED((unsigned long)va, size) || bad_size);
 332
 333         return slow_virt_to_phys(va);
 334 }
 335
 336 #define virt_to_phys_or_null(addr)                              \
 337         virt_to_phys_or_null_size((addr), sizeof(*(addr)))
 338
 339 int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
 340 {
 341         unsigned long pfn, text, pf;
 342         struct page *page;
 343         unsigned npages;
 344         pgd_t *pgd = efi_mm.pgd;
 345
 346         if (efi_enabled(EFI_OLD_MEMMAP))
 347                 return 0;
 348
 349         /*
 350          * It can happen that the physical address of new_memmap lands in memory
 351          * which is not mapped in the EFI page table. Therefore we need to go
 352          * and ident-map those pages containing the map before calling
 353          * phys_efi_set_virtual_address_map().
 354          */
 355         pfn = pa_memmap >> PAGE_SHIFT;
 356         pf = _PAGE_NX | _PAGE_RW | _PAGE_ENC;
 357         if (kernel_map_pages_in_pgd(pgd, pfn, pa_memmap, num_pages, pf)) {
 358                 pr_err("Error ident-mapping new memmap (0x%lx)!\n", pa_memmap);
 359                 return 1;
 360         }
 361
 362         /*
 363          * Certain firmware versions are way too sentimential and still believe
 364          * they are exclusive and unquestionable owners of the first physical page,
 365          * even though they explicitly mark it as EFI_CONVENTIONAL_MEMORY
 366          * (but then write-access it later during SetVirtualAddressMap()).
 367          *
 368          * Create a 1:1 mapping for this page, to avoid triple faults during early
 369          * boot with such firmware. We are free to hand this page to the BIOS,
 370          * as trim_bios_range() will reserve the first page and isolate it away
 371          * from memory allocators anyway.
 372          */
 373         pf = _PAGE_RW;
 374         if (sev_active())
 375                 pf |= _PAGE_ENC;
 376
 377         if (kernel_map_pages_in_pgd(pgd, 0x0, 0x0, 1, pf)) {
 378                 pr_err("Failed to create 1:1 mapping for the first page!\n");
 379                 return 1;
 380         }
 381
 382         /*
 383          * When making calls to the firmware everything needs to be 1:1
 384          * mapped and addressable with 32-bit pointers. Map the kernel
 385          * text and allocate a new stack because we can't rely on the
 386          * stack pointer being < 4GB.
 387          */
 388         if (!IS_ENABLED(CONFIG_EFI_MIXED) || efi_is_native())
 389                 return 0;
 390
 391         page = alloc_page(GFP_KERNEL|__GFP_DMA32);
 392         if (!page)
 393                 panic("Unable to allocate EFI runtime stack < 4GB\n");
 394
 395         efi_scratch.phys_stack = virt_to_phys(page_address(page));
 396         efi_scratch.phys_stack += PAGE_SIZE; /* stack grows down */
 397
 398         npages = (_etext - _text) >> PAGE_SHIFT;
 399         text = __pa(_text);
 400         pfn = text >> PAGE_SHIFT;
 401
 402         pf = _PAGE_RW | _PAGE_ENC;
 403         if (kernel_map_pages_in_pgd(pgd, pfn, text, npages, pf)) {
 404                 pr_err("Failed to map kernel text 1:1\n");
 405                 return 1;
 406         }
 407
 408         return 0;
 409 }
 410
 411 static void __init __map_region(efi_memory_desc_t *md, u64 va)
 412 {
 413         unsigned long flags = _PAGE_RW;
 414         unsigned long pfn;
 415         pgd_t *pgd = efi_mm.pgd;
 416
 417         if (!(md->attribute & EFI_MEMORY_WB))
 418                 flags |= _PAGE_PCD;
 419
 420         if (sev_active() && md->type != EFI_MEMORY_MAPPED_IO)
 421                 flags |= _PAGE_ENC;
 422
 423         pfn = md->phys_addr >> PAGE_SHIFT;
 424         if (kernel_map_pages_in_pgd(pgd, pfn, va, md->num_pages, flags))
 425                 pr_warn("Error mapping PA 0x%llx -> VA 0x%llx!\n",
 426                            md->phys_addr, va);
 427 }
 428
 429 void __init efi_map_region(efi_memory_desc_t *md)
 430 {
 431         unsigned long size = md->num_pages << PAGE_SHIFT;
 432         u64 pa = md->phys_addr;
 433
 434         if (efi_enabled(EFI_OLD_MEMMAP))
 435                 return old_map_region(md);
 436
 437         /*
 438          * Make sure the 1:1 mappings are present as a catch-all for b0rked
 439          * firmware which doesn't update all internal pointers after switching
 440          * to virtual mode and would otherwise crap on us.
 441          */
 442         __map_region(md, md->phys_addr);
 443
 444         /*
 445          * Enforce the 1:1 mapping as the default virtual address when
 446          * booting in EFI mixed mode, because even though we may be
 447          * running a 64-bit kernel, the firmware may only be 32-bit.
 448          */
 449         if (!efi_is_native () && IS_ENABLED(CONFIG_EFI_MIXED)) {
 450                 md->virt_addr = md->phys_addr;
 451                 return;
 452         }
 453
 454         efi_va -= size;
 455
 456         /* Is PA 2M-aligned? */
 457         if (!(pa & (PMD_SIZE - 1))) {
 458                 efi_va &= PMD_MASK;
 459         } else {
 460                 u64 pa_offset = pa & (PMD_SIZE - 1);
 461                 u64 prev_va = efi_va;
 462
 463                 /* get us the same offset within this 2M page */
 464                 efi_va = (efi_va & PMD_MASK) + pa_offset;
 465
 466                 if (efi_va > prev_va)
 467                         efi_va -= PMD_SIZE;
 468         }
 469
 470         if (efi_va < EFI_VA_END) {
 471                 pr_warn(FW_WARN "VA address range overflow!\n");
 472                 return;
 473         }
 474
 475         /* Do the VA map */
 476         __map_region(md, efi_va);
 477         md->virt_addr = efi_va;
 478 }
 479
 480 /*
 481  * kexec kernel will use efi_map_region_fixed to map efi runtime memory ranges.
 482  * md->virt_addr is the original virtual address which had been mapped in kexec
 483  * 1st kernel.
 484  */
 485 void __init efi_map_region_fixed(efi_memory_desc_t *md)
 486 {
 487         __map_region(md, md->phys_addr);
 488         __map_region(md, md->virt_addr);
 489 }
 490
 491 void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
 492                                  u32 type, u64 attribute)
 493 {
 494         unsigned long last_map_pfn;
 495
 496         if (type == EFI_MEMORY_MAPPED_IO)
 497                 return ioremap(phys_addr, size);
 498
 499         last_map_pfn = init_memory_mapping(phys_addr, phys_addr + size);
 500         if ((last_map_pfn << PAGE_SHIFT) < phys_addr + size) {
 501                 unsigned long top = last_map_pfn << PAGE_SHIFT;
 502                 efi_ioremap(top, size - (top - phys_addr), type, attribute);
 503         }
 504
 505         if (!(attribute & EFI_MEMORY_WB))
 506                 efi_memory_uc((u64)(unsigned long)__va(phys_addr), size);
 507
 508         return (void __iomem *)__va(phys_addr);
 509 }
 510
 511 void __init parse_efi_setup(u64 phys_addr, u32 data_len)
 512 {
 513         efi_setup = phys_addr + sizeof(struct setup_data);
 514 }
 515
 516 static int __init efi_update_mappings(efi_memory_desc_t *md, unsigned long pf)
 517 {
 518         unsigned long pfn;
 519         pgd_t *pgd = efi_mm.pgd;
 520         int err1, err2;
 521
 522         /* Update the 1:1 mapping */
 523         pfn = md->phys_addr >> PAGE_SHIFT;
 524         err1 = kernel_map_pages_in_pgd(pgd, pfn, md->phys_addr, md->num_pages, pf);
 525         if (err1) {
 526                 pr_err("Error while updating 1:1 mapping PA 0x%llx -> VA 0x%llx!\n",
 527                            md->phys_addr, md->virt_addr);
 528         }
 529
 530         err2 = kernel_map_pages_in_pgd(pgd, pfn, md->virt_addr, md->num_pages, pf);
 531         if (err2) {
 532                 pr_err("Error while updating VA mapping PA 0x%llx -> VA 0x%llx!\n",
 533                            md->phys_addr, md->virt_addr);
 534         }
 535
 536         return err1 || err2;
 537 }
 538
 539 static int __init efi_update_mem_attr(struct mm_struct *mm, efi_memory_desc_t *md)
 540 {
 541         unsigned long pf = 0;
 542
 543         if (md->attribute & EFI_MEMORY_XP)
 544                 pf |= _PAGE_NX;
 545
 546         if (!(md->attribute & EFI_MEMORY_RO))
 547                 pf |= _PAGE_RW;
 548
 549         if (sev_active())
 550                 pf |= _PAGE_ENC;
 551
 552         return efi_update_mappings(md, pf);
 553 }
 554
 555 void __init efi_runtime_update_mappings(void)
 556 {
 557         efi_memory_desc_t *md;
 558
 559         if (efi_enabled(EFI_OLD_MEMMAP)) {
 560                 if (__supported_pte_mask & _PAGE_NX)
 561                         runtime_code_page_mkexec();
 562                 return;
 563         }
 564
 565         /*
 566          * Use the EFI Memory Attribute Table for mapping permissions if it
 567          * exists, since it is intended to supersede EFI_PROPERTIES_TABLE.
 568          */
 569         if (efi_enabled(EFI_MEM_ATTR)) {
 570                 efi_memattr_apply_permissions(NULL, efi_update_mem_attr);
 571                 return;
 572         }
 573
 574         /*
 575          * EFI_MEMORY_ATTRIBUTES_TABLE is intended to replace
 576          * EFI_PROPERTIES_TABLE. So, use EFI_PROPERTIES_TABLE to update
 577          * permissions only if EFI_MEMORY_ATTRIBUTES_TABLE is not
 578          * published by the firmware. Even if we find a buggy implementation of
 579          * EFI_MEMORY_ATTRIBUTES_TABLE, don't fall back to
 580          * EFI_PROPERTIES_TABLE, because of the same reason.
 581          */
 582
 583         if (!efi_enabled(EFI_NX_PE_DATA))
 584                 return;
 585
 586         for_each_efi_memory_desc(md) {
 587                 unsigned long pf = 0;
 588
 589                 if (!(md->attribute & EFI_MEMORY_RUNTIME))
 590                         continue;
 591
 592                 if (!(md->attribute & EFI_MEMORY_WB))
 593                         pf |= _PAGE_PCD;
 594
 595                 if ((md->attribute & EFI_MEMORY_XP) ||
 596                         (md->type == EFI_RUNTIME_SERVICES_DATA))
 597                         pf |= _PAGE_NX;
 598
 599                 if (!(md->attribute & EFI_MEMORY_RO) &&
 600                         (md->type != EFI_RUNTIME_SERVICES_CODE))
 601                         pf |= _PAGE_RW;
 602
 603                 if (sev_active())
 604                         pf |= _PAGE_ENC;
 605
 606                 efi_update_mappings(md, pf);
 607         }
 608 }
 609
 610 void __init efi_dump_pagetable(void)
 611 {
 612 #ifdef CONFIG_EFI_PGT_DUMP
 613         if (efi_enabled(EFI_OLD_MEMMAP))
 614                 ptdump_walk_pgd_level(NULL, swapper_pg_dir);
 615         else
 616                 ptdump_walk_pgd_level(NULL, efi_mm.pgd);
 617 #endif
 618 }
 619
 620 /*
 621  * Makes the calling thread switch to/from efi_mm context. Can be used
 622  * for SetVirtualAddressMap() i.e. current->active_mm == init_mm as well
 623  * as during efi runtime calls i.e current->active_mm == current_mm.
 624  * We are not mm_dropping()/mm_grabbing() any mm, because we are not
 625  * losing/creating any references.
 626  */
 627 void efi_switch_mm(struct mm_struct *mm)
 628 {
 629         task_lock(current);
 630         efi_scratch.prev_mm = current->active_mm;
 631         current->active_mm = mm;
 632         switch_mm(efi_scratch.prev_mm, mm, NULL);
 633         task_unlock(current);
 634 }
 635
 636 #ifdef CONFIG_EFI_MIXED
 637 extern efi_status_t efi64_thunk(u32, ...);
 638
 639 static DEFINE_SPINLOCK(efi_runtime_lock);
 640
 641 #define runtime_service32(func)                                          \
 642 ({                                                                       \
 643         u32 table = (u32)(unsigned long)efi.systab;                      \
 644         u32 *rt, *___f;                                                  \
 645                                                                          \
 646         rt = (u32 *)(table + offsetof(efi_system_table_32_t, runtime));  \
 647         ___f = (u32 *)(*rt + offsetof(efi_runtime_services_32_t, func)); \
 648         *___f;                                                           \
 649 })
 650
 651 /*
 652  * Switch to the EFI page tables early so that we can access the 1:1
 653  * runtime services mappings which are not mapped in any other page
 654  * tables. This function must be called before runtime_service32().
 655  *
 656  * Also, disable interrupts because the IDT points to 64-bit handlers,
 657  * which aren't going to function correctly when we switch to 32-bit.
 658  */
 659 #define efi_thunk(f, ...)                                               \
 660 ({                                                                      \
 661         efi_status_t __s;                                               \
 662         u32 __func;                                                     \
 663                                                                         \
 664         arch_efi_call_virt_setup();                                     \
 665                                                                         \
 666         __func = runtime_service32(f);                                  \
 667         __s = efi64_thunk(__func, __VA_ARGS__);                         \
 668                                                                         \
 669         arch_efi_call_virt_teardown();                                  \
 670                                                                         \
 671         __s;                                                            \
 672 })
 673
 674 efi_status_t efi_thunk_set_virtual_address_map(
 675         void *phys_set_virtual_address_map,
 676         unsigned long memory_map_size,
 677         unsigned long descriptor_size,
 678         u32 descriptor_version,
 679         efi_memory_desc_t *virtual_map)
 680 {
 681         efi_status_t status;
 682         unsigned long flags;
 683         u32 func;
 684
 685         efi_sync_low_kernel_mappings();
 686         local_irq_save(flags);
 687
 688         efi_switch_mm(&efi_mm);
 689
 690         func = (u32)(unsigned long)phys_set_virtual_address_map;
 691         status = efi64_thunk(func, memory_map_size, descriptor_size,
 692                              descriptor_version, virtual_map);
 693
 694         efi_switch_mm(efi_scratch.prev_mm);
 695         local_irq_restore(flags);
 696
 697         return status;
 698 }
 699
 700 static efi_status_t efi_thunk_get_time(efi_time_t *tm, efi_time_cap_t *tc)
 701 {
 702         efi_status_t status;
 703         u32 phys_tm, phys_tc;
 704         unsigned long flags;
 705
 706         spin_lock(&rtc_lock);
 707         spin_lock_irqsave(&efi_runtime_lock, flags);
 708
 709         phys_tm = virt_to_phys_or_null(tm);
 710         phys_tc = virt_to_phys_or_null(tc);
 711
 712         status = efi_thunk(get_time, phys_tm, phys_tc);
 713
 714         spin_unlock_irqrestore(&efi_runtime_lock, flags);
 715         spin_unlock(&rtc_lock);
 716
 717         return status;
 718 }
 719
 720 static efi_status_t efi_thunk_set_time(efi_time_t *tm)
 721 {
 722         efi_status_t status;
 723         u32 phys_tm;
 724         unsigned long flags;
 725
 726         spin_lock(&rtc_lock);
 727         spin_lock_irqsave(&efi_runtime_lock, flags);
 728
 729         phys_tm = virt_to_phys_or_null(tm);
 730
 731         status = efi_thunk(set_time, phys_tm);
 732
 733         spin_unlock_irqrestore(&efi_runtime_lock, flags);
 734         spin_unlock(&rtc_lock);
 735
 736         return status;
 737 }
 738
 739 static efi_status_t
 740 efi_thunk_get_wakeup_time(efi_bool_t *enabled, efi_bool_t *pending,
 741                           efi_time_t *tm)
 742 {
 743         efi_status_t status;
 744         u32 phys_enabled, phys_pending, phys_tm;
 745         unsigned long flags;
 746
 747         spin_lock(&rtc_lock);
 748         spin_lock_irqsave(&efi_runtime_lock, flags);
 749
 750         phys_enabled = virt_to_phys_or_null(enabled);
 751         phys_pending = virt_to_phys_or_null(pending);
 752         phys_tm = virt_to_phys_or_null(tm);
 753
 754         status = efi_thunk(get_wakeup_time, phys_enabled,
 755                              phys_pending, phys_tm);
 756
 757         spin_unlock_irqrestore(&efi_runtime_lock, flags);
 758         spin_unlock(&rtc_lock);
 759
 760         return status;
 761 }
 762
 763 static efi_status_t
 764 efi_thunk_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm)
 765 {
 766         efi_status_t status;
 767         u32 phys_tm;
 768         unsigned long flags;
 769
 770         spin_lock(&rtc_lock);
 771         spin_lock_irqsave(&efi_runtime_lock, flags);
 772
 773         phys_tm = virt_to_phys_or_null(tm);
 774
 775         status = efi_thunk(set_wakeup_time, enabled, phys_tm);
 776
 777         spin_unlock_irqrestore(&efi_runtime_lock, flags);
 778         spin_unlock(&rtc_lock);
 779
 780         return status;
 781 }
 782
 783 static unsigned long efi_name_size(efi_char16_t *name)
 784 {
 785         return ucs2_strsize(name, EFI_VAR_NAME_LEN) + 1;
 786 }
 787
 788 static efi_status_t
 789 efi_thunk_get_variable(efi_char16_t *name, efi_guid_t *vendor,
 790                        u32 *attr, unsigned long *data_size, void *data)
 791 {
 792         efi_status_t status;
 793         u32 phys_name, phys_vendor, phys_attr;
 794         u32 phys_data_size, phys_data;
 795         unsigned long flags;
 796
 797         spin_lock_irqsave(&efi_runtime_lock, flags);
 798
 799         phys_data_size = virt_to_phys_or_null(data_size);
 800         phys_vendor = virt_to_phys_or_null(vendor);
 801         phys_name = virt_to_phys_or_null_size(name, efi_name_size(name));
 802         phys_attr = virt_to_phys_or_null(attr);
 803         phys_data = virt_to_phys_or_null_size(data, *data_size);
 804
 805         status = efi_thunk(get_variable, phys_name, phys_vendor,
 806                            phys_attr, phys_data_size, phys_data);
 807
 808         spin_unlock_irqrestore(&efi_runtime_lock, flags);
 809
 810         return status;
 811 }
 812
 813 static efi_status_t
 814 efi_thunk_set_variable(efi_char16_t *name, efi_guid_t *vendor,
 815                        u32 attr, unsigned long data_size, void *data)
 816 {
 817         u32 phys_name, phys_vendor, phys_data;
 818         efi_status_t status;
 819         unsigned long flags;
 820
 821         spin_lock_irqsave(&efi_runtime_lock, flags);
 822
 823         phys_name = virt_to_phys_or_null_size(name, efi_name_size(name));
 824         phys_vendor = virt_to_phys_or_null(vendor);
 825         phys_data = virt_to_phys_or_null_size(data, data_size);
 826
 827         /* If data_size is > sizeof(u32) we've got problems */
 828         status = efi_thunk(set_variable, phys_name, phys_vendor,
 829                            attr, data_size, phys_data);
 830
 831         spin_unlock_irqrestore(&efi_runtime_lock, flags);
 832
 833         return status;
 834 }
 835
 836 static efi_status_t
 837 efi_thunk_set_variable_nonblocking(efi_char16_t *name, efi_guid_t *vendor,
 838                                    u32 attr, unsigned long data_size,
 839                                    void *data)
 840 {
 841         u32 phys_name, phys_vendor, phys_data;
 842         efi_status_t status;
 843         unsigned long flags;
 844
 845         if (!spin_trylock_irqsave(&efi_runtime_lock, flags))
 846                 return EFI_NOT_READY;
 847
 848         phys_name = virt_to_phys_or_null_size(name, efi_name_size(name));
 849         phys_vendor = virt_to_phys_or_null(vendor);
 850         phys_data = virt_to_phys_or_null_size(data, data_size);
 851
 852         /* If data_size is > sizeof(u32) we've got problems */
 853         status = efi_thunk(set_variable, phys_name, phys_vendor,
 854                            attr, data_size, phys_data);
 855
 856         spin_unlock_irqrestore(&efi_runtime_lock, flags);
 857
 858         return status;
 859 }
 860
 861 static efi_status_t
 862 efi_thunk_get_next_variable(unsigned long *name_size,
 863                             efi_char16_t *name,
 864                             efi_guid_t *vendor)
 865 {
 866         efi_status_t status;
 867         u32 phys_name_size, phys_name, phys_vendor;
 868         unsigned long flags;
 869
 870         spin_lock_irqsave(&efi_runtime_lock, flags);
 871
 872         phys_name_size = virt_to_phys_or_null(name_size);
 873         phys_vendor = virt_to_phys_or_null(vendor);
 874         phys_name = virt_to_phys_or_null_size(name, *name_size);
 875
 876         status = efi_thunk(get_next_variable, phys_name_size,
 877                            phys_name, phys_vendor);
 878
 879         spin_unlock_irqrestore(&efi_runtime_lock, flags);
 880
 881         return status;
 882 }
 883
 884 static efi_status_t
 885 efi_thunk_get_next_high_mono_count(u32 *count)
 886 {
 887         efi_status_t status;
 888         u32 phys_count;
 889         unsigned long flags;
 890
 891         spin_lock_irqsave(&efi_runtime_lock, flags);
 892
 893         phys_count = virt_to_phys_or_null(count);
 894         status = efi_thunk(get_next_high_mono_count, phys_count);
 895
 896         spin_unlock_irqrestore(&efi_runtime_lock, flags);
 897
 898         return status;
 899 }
 900
 901 static void
 902 efi_thunk_reset_system(int reset_type, efi_status_t status,
 903                        unsigned long data_size, efi_char16_t *data)
 904 {
 905         u32 phys_data;
 906         unsigned long flags;
 907
 908         spin_lock_irqsave(&efi_runtime_lock, flags);
 909
 910         phys_data = virt_to_phys_or_null_size(data, data_size);
 911
 912         efi_thunk(reset_system, reset_type, status, data_size, phys_data);
 913
 914         spin_unlock_irqrestore(&efi_runtime_lock, flags);
 915 }
 916
 917 static efi_status_t
 918 efi_thunk_update_capsule(efi_capsule_header_t **capsules,
 919                          unsigned long count, unsigned long sg_list)
 920 {
 921         /*
 922          * To properly support this function we would need to repackage
 923          * 'capsules' because the firmware doesn't understand 64-bit
 924          * pointers.
 925          */
 926         return EFI_UNSUPPORTED;
 927 }
 928
 929 static efi_status_t
 930 efi_thunk_query_variable_info(u32 attr, u64 *storage_space,
 931                               u64 *remaining_space,
 932                               u64 *max_variable_size)
 933 {
 934         efi_status_t status;
 935         u32 phys_storage, phys_remaining, phys_max;
 936         unsigned long flags;
 937
 938         if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
 939                 return EFI_UNSUPPORTED;
 940
 941         spin_lock_irqsave(&efi_runtime_lock, flags);
 942
 943         phys_storage = virt_to_phys_or_null(storage_space);
 944         phys_remaining = virt_to_phys_or_null(remaining_space);
 945         phys_max = virt_to_phys_or_null(max_variable_size);
 946
 947         status = efi_thunk(query_variable_info, attr, phys_storage,
 948                            phys_remaining, phys_max);
 949
 950         spin_unlock_irqrestore(&efi_runtime_lock, flags);
 951
 952         return status;
 953 }
 954
 955 static efi_status_t
 956 efi_thunk_query_variable_info_nonblocking(u32 attr, u64 *storage_space,
 957                                           u64 *remaining_space,
 958                                           u64 *max_variable_size)
 959 {
 960         efi_status_t status;
 961         u32 phys_storage, phys_remaining, phys_max;
 962         unsigned long flags;
 963
 964         if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
 965                 return EFI_UNSUPPORTED;
 966
 967         if (!spin_trylock_irqsave(&efi_runtime_lock, flags))
 968                 return EFI_NOT_READY;
 969
 970         phys_storage = virt_to_phys_or_null(storage_space);
 971         phys_remaining = virt_to_phys_or_null(remaining_space);
 972         phys_max = virt_to_phys_or_null(max_variable_size);
 973
 974         status = efi_thunk(query_variable_info, attr, phys_storage,
 975                            phys_remaining, phys_max);
 976
 977         spin_unlock_irqrestore(&efi_runtime_lock, flags);
 978
 979         return status;
 980 }
 981
 982 static efi_status_t
 983 efi_thunk_query_capsule_caps(efi_capsule_header_t **capsules,
 984                              unsigned long count, u64 *max_size,
 985                              int *reset_type)
 986 {
 987         /*
 988          * To properly support this function we would need to repackage
 989          * 'capsules' because the firmware doesn't understand 64-bit
 990          * pointers.
 991          */
 992         return EFI_UNSUPPORTED;
 993 }
 994
 995 void efi_thunk_runtime_setup(void)
 996 {
 997         efi.get_time = efi_thunk_get_time;
 998         efi.set_time = efi_thunk_set_time;
 999         efi.get_wakeup_time = efi_thunk_get_wakeup_time;
1000         efi.set_wakeup_time = efi_thunk_set_wakeup_time;
1001         efi.get_variable = efi_thunk_get_variable;
1002         efi.get_next_variable = efi_thunk_get_next_variable;
1003         efi.set_variable = efi_thunk_set_variable;
1004         efi.set_variable_nonblocking = efi_thunk_set_variable_nonblocking;
1005         efi.get_next_high_mono_count = efi_thunk_get_next_high_mono_count;
1006         efi.reset_system = efi_thunk_reset_system;
1007         efi.query_variable_info = efi_thunk_query_variable_info;
1008         efi.query_variable_info_nonblocking = efi_thunk_query_variable_info_nonblocking;
1009         efi.update_capsule = efi_thunk_update_capsule;
1010         efi.query_capsule_caps = efi_thunk_query_capsule_caps;
1011 }
1012 #endif /* CONFIG_EFI_MIXED */