arch/x86/platform/efi/efi_64.c

   1 /*
   2  * x86_64 specific EFI support functions
   3  * Based on Extensible Firmware Interface Specification version 1.0
   4  *
   5  * Copyright (C) 2005-2008 Intel Co.
   6  *      Fenghua Yu <fenghua.yu@intel.com>
   7  *      Bibo Mao <bibo.mao@intel.com>
   8  *      Chandramouli Narayanan <mouli@linux.intel.com>
   9  *      Huang Ying <ying.huang@intel.com>
  10  *
  11  * Code to convert EFI to E820 map has been implemented in elilo bootloader
  12  * based on a EFI patch by Edgar Hucek. Based on the E820 map, the page table
  13  * is setup appropriately for EFI runtime code.
  14  * - mouli 06/14/2007.
  15  *
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/init.h>
  20 #include <linux/mm.h>
  21 #include <linux/types.h>
  22 #include <linux/spinlock.h>
  23 #include <linux/bootmem.h>
  24 #include <linux/ioport.h>
  25 #include <linux/module.h>
  26 #include <linux/efi.h>
  27 #include <linux/uaccess.h>
  28 #include <linux/io.h>
  29 #include <linux/reboot.h>
  30 #include <linux/slab.h>
  31
  32 #include <asm/setup.h>
  33 #include <asm/page.h>
  34 #include <asm/e820.h>
  35 #include <asm/pgtable.h>
  36 #include <asm/tlbflush.h>
  37 #include <asm/proto.h>
  38 #include <asm/efi.h>
  39 #include <asm/cacheflush.h>
  40 #include <asm/fixmap.h>
  41 #include <asm/realmode.h>
  42 #include <asm/time.h>
  43
  44 /*
  45  * We allocate runtime services regions bottom-up, starting from -4G, i.e.
  46  * 0xffff_ffff_0000_0000 and limit EFI VA mapping space to 64G.
  47  */
  48 static u64 efi_va = EFI_VA_START;
  49
  50 /*
  51  * Scratch space used for switching the pagetable in the EFI stub
  52  */
  53 struct efi_scratch {
  54         u64 r15;
  55         u64 prev_cr3;
  56         pgd_t *efi_pgt;
  57         bool use_pgd;
  58         u64 phys_stack;
  59 } __packed;
  60
  61 static void __init early_code_mapping_set_exec(int executable)
  62 {
  63         efi_memory_desc_t *md;
  64         void *p;
  65
  66         if (!(__supported_pte_mask & _PAGE_NX))
  67                 return;
  68
  69         /* Make EFI service code area executable */
  70         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
  71                 md = p;
  72                 if (md->type == EFI_RUNTIME_SERVICES_CODE ||
  73                     md->type == EFI_BOOT_SERVICES_CODE)
  74                         efi_set_executable(md, executable);
  75         }
  76 }
  77
  78 pgd_t * __init efi_call_phys_prolog(void)
  79 {
  80         unsigned long vaddress;
  81         pgd_t *save_pgd;
  82
  83         int pgd;
  84         int n_pgds;
  85
  86         if (!efi_enabled(EFI_OLD_MEMMAP))
  87                 return NULL;
  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(n_pgds * sizeof(pgd_t), GFP_KERNEL);
  93
  94         for (pgd = 0; pgd < n_pgds; pgd++) {
  95                 save_pgd[pgd] = *pgd_offset_k(pgd * PGDIR_SIZE);
  96                 vaddress = (unsigned long)__va(pgd * PGDIR_SIZE);
  97                 set_pgd(pgd_offset_k(pgd * PGDIR_SIZE), *pgd_offset_k(vaddress));
  98         }
  99         __flush_tlb_all();
 100
 101         return save_pgd;
 102 }
 103
 104 void __init efi_call_phys_epilog(pgd_t *save_pgd)
 105 {
 106         /*
 107          * After the lock is released, the original page table is restored.
 108          */
 109         int pgd_idx;
 110         int nr_pgds;
 111
 112         if (!save_pgd)
 113                 return;
 114
 115         nr_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT) , PGDIR_SIZE);
 116
 117         for (pgd_idx = 0; pgd_idx < nr_pgds; pgd_idx++)
 118                 set_pgd(pgd_offset_k(pgd_idx * PGDIR_SIZE), save_pgd[pgd_idx]);
 119
 120         kfree(save_pgd);
 121
 122         __flush_tlb_all();
 123         early_code_mapping_set_exec(0);
 124 }
 125
 126 /*
 127  * Add low kernel mappings for passing arguments to EFI functions.
 128  */
 129 void efi_sync_low_kernel_mappings(void)
 130 {
 131         unsigned num_pgds;
 132         pgd_t *pgd = (pgd_t *)__va(real_mode_header->trampoline_pgd);
 133
 134         if (efi_enabled(EFI_OLD_MEMMAP))
 135                 return;
 136
 137         num_pgds = pgd_index(MODULES_END - 1) - pgd_index(PAGE_OFFSET);
 138
 139         memcpy(pgd + pgd_index(PAGE_OFFSET),
 140                 init_mm.pgd + pgd_index(PAGE_OFFSET),
 141                 sizeof(pgd_t) * num_pgds);
 142 }
 143
 144 int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
 145 {
 146         unsigned long text;
 147         struct page *page;
 148         unsigned npages;
 149         pgd_t *pgd;
 150
 151         if (efi_enabled(EFI_OLD_MEMMAP))
 152                 return 0;
 153
 154         efi_scratch.efi_pgt = (pgd_t *)(unsigned long)real_mode_header->trampoline_pgd;
 155         pgd = __va(efi_scratch.efi_pgt);
 156
 157         /*
 158          * It can happen that the physical address of new_memmap lands in memory
 159          * which is not mapped in the EFI page table. Therefore we need to go
 160          * and ident-map those pages containing the map before calling
 161          * phys_efi_set_virtual_address_map().
 162          */
 163         if (kernel_map_pages_in_pgd(pgd, pa_memmap, pa_memmap, num_pages, _PAGE_NX)) {
 164                 pr_err("Error ident-mapping new memmap (0x%lx)!\n", pa_memmap);
 165                 return 1;
 166         }
 167
 168         efi_scratch.use_pgd = true;
 169
 170         /*
 171          * When making calls to the firmware everything needs to be 1:1
 172          * mapped and addressable with 32-bit pointers. Map the kernel
 173          * text and allocate a new stack because we can't rely on the
 174          * stack pointer being < 4GB.
 175          */
 176         if (!IS_ENABLED(CONFIG_EFI_MIXED))
 177                 return 0;
 178
 179         page = alloc_page(GFP_KERNEL|__GFP_DMA32);
 180         if (!page)
 181                 panic("Unable to allocate EFI runtime stack < 4GB\n");
 182
 183         efi_scratch.phys_stack = virt_to_phys(page_address(page));
 184         efi_scratch.phys_stack += PAGE_SIZE; /* stack grows down */
 185
 186         npages = (_end - _text) >> PAGE_SHIFT;
 187         text = __pa(_text);
 188
 189         if (kernel_map_pages_in_pgd(pgd, text >> PAGE_SHIFT, text, npages, 0)) {
 190                 pr_err("Failed to map kernel text 1:1\n");
 191                 return 1;
 192         }
 193
 194         return 0;
 195 }
 196
 197 void __init efi_cleanup_page_tables(unsigned long pa_memmap, unsigned num_pages)
 198 {
 199         pgd_t *pgd = (pgd_t *)__va(real_mode_header->trampoline_pgd);
 200
 201         kernel_unmap_pages_in_pgd(pgd, pa_memmap, num_pages);
 202 }
 203
 204 static void __init __map_region(efi_memory_desc_t *md, u64 va)
 205 {
 206         pgd_t *pgd = (pgd_t *)__va(real_mode_header->trampoline_pgd);
 207         unsigned long pf = 0;
 208
 209         if (!(md->attribute & EFI_MEMORY_WB))
 210                 pf |= _PAGE_PCD;
 211
 212         if (kernel_map_pages_in_pgd(pgd, md->phys_addr, va, md->num_pages, pf))
 213                 pr_warn("Error mapping PA 0x%llx -> VA 0x%llx!\n",
 214                            md->phys_addr, va);
 215 }
 216
 217 void __init efi_map_region(efi_memory_desc_t *md)
 218 {
 219         unsigned long size = md->num_pages << PAGE_SHIFT;
 220         u64 pa = md->phys_addr;
 221
 222         if (efi_enabled(EFI_OLD_MEMMAP))
 223                 return old_map_region(md);
 224
 225         /*
 226          * Make sure the 1:1 mappings are present as a catch-all for b0rked
 227          * firmware which doesn't update all internal pointers after switching
 228          * to virtual mode and would otherwise crap on us.
 229          */
 230         __map_region(md, md->phys_addr);
 231
 232         /*
 233          * Enforce the 1:1 mapping as the default virtual address when
 234          * booting in EFI mixed mode, because even though we may be
 235          * running a 64-bit kernel, the firmware may only be 32-bit.
 236          */
 237         if (!efi_is_native () && IS_ENABLED(CONFIG_EFI_MIXED)) {
 238                 md->virt_addr = md->phys_addr;
 239                 return;
 240         }
 241
 242         efi_va -= size;
 243
 244         /* Is PA 2M-aligned? */
 245         if (!(pa & (PMD_SIZE - 1))) {
 246                 efi_va &= PMD_MASK;
 247         } else {
 248                 u64 pa_offset = pa & (PMD_SIZE - 1);
 249                 u64 prev_va = efi_va;
 250
 251                 /* get us the same offset within this 2M page */
 252                 efi_va = (efi_va & PMD_MASK) + pa_offset;
 253
 254                 if (efi_va > prev_va)
 255                         efi_va -= PMD_SIZE;
 256         }
 257
 258         if (efi_va < EFI_VA_END) {
 259                 pr_warn(FW_WARN "VA address range overflow!\n");
 260                 return;
 261         }
 262
 263         /* Do the VA map */
 264         __map_region(md, efi_va);
 265         md->virt_addr = efi_va;
 266 }
 267
 268 /*
 269  * kexec kernel will use efi_map_region_fixed to map efi runtime memory ranges.
 270  * md->virt_addr is the original virtual address which had been mapped in kexec
 271  * 1st kernel.
 272  */
 273 void __init efi_map_region_fixed(efi_memory_desc_t *md)
 274 {
 275         __map_region(md, md->virt_addr);
 276 }
 277
 278 void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
 279                                  u32 type, u64 attribute)
 280 {
 281         unsigned long last_map_pfn;
 282
 283         if (type == EFI_MEMORY_MAPPED_IO)
 284                 return ioremap(phys_addr, size);
 285
 286         last_map_pfn = init_memory_mapping(phys_addr, phys_addr + size);
 287         if ((last_map_pfn << PAGE_SHIFT) < phys_addr + size) {
 288                 unsigned long top = last_map_pfn << PAGE_SHIFT;
 289                 efi_ioremap(top, size - (top - phys_addr), type, attribute);
 290         }
 291
 292         if (!(attribute & EFI_MEMORY_WB))
 293                 efi_memory_uc((u64)(unsigned long)__va(phys_addr), size);
 294
 295         return (void __iomem *)__va(phys_addr);
 296 }
 297
 298 void __init parse_efi_setup(u64 phys_addr, u32 data_len)
 299 {
 300         efi_setup = phys_addr + sizeof(struct setup_data);
 301 }
 302
 303 void __init efi_runtime_mkexec(void)
 304 {
 305         if (!efi_enabled(EFI_OLD_MEMMAP))
 306                 return;
 307
 308         if (__supported_pte_mask & _PAGE_NX)
 309                 runtime_code_page_mkexec();
 310 }
 311
 312 void __init efi_dump_pagetable(void)
 313 {
 314 #ifdef CONFIG_EFI_PGT_DUMP
 315         pgd_t *pgd = (pgd_t *)__va(real_mode_header->trampoline_pgd);
 316
 317         ptdump_walk_pgd_level(NULL, pgd);
 318 #endif
 319 }
 320
 321 #ifdef CONFIG_EFI_MIXED
 322 extern efi_status_t efi64_thunk(u32, ...);
 323
 324 #define runtime_service32(func)                                          \
 325 ({                                                                       \
 326         u32 table = (u32)(unsigned long)efi.systab;                      \
 327         u32 *rt, *___f;                                                  \
 328                                                                          \
 329         rt = (u32 *)(table + offsetof(efi_system_table_32_t, runtime));  \
 330         ___f = (u32 *)(*rt + offsetof(efi_runtime_services_32_t, func)); \
 331         *___f;                                                           \
 332 })
 333
 334 /*
 335  * Switch to the EFI page tables early so that we can access the 1:1
 336  * runtime services mappings which are not mapped in any other page
 337  * tables. This function must be called before runtime_service32().
 338  *
 339  * Also, disable interrupts because the IDT points to 64-bit handlers,
 340  * which aren't going to function correctly when we switch to 32-bit.
 341  */
 342 #define efi_thunk(f, ...)                                               \
 343 ({                                                                      \
 344         efi_status_t __s;                                               \
 345         unsigned long flags;                                            \
 346         u32 func;                                                       \
 347                                                                         \
 348         efi_sync_low_kernel_mappings();                                 \
 349         local_irq_save(flags);                                          \
 350                                                                         \
 351         efi_scratch.prev_cr3 = read_cr3();                              \
 352         write_cr3((unsigned long)efi_scratch.efi_pgt);                  \
 353         __flush_tlb_all();                                              \
 354                                                                         \
 355         func = runtime_service32(f);                                    \
 356         __s = efi64_thunk(func, __VA_ARGS__);                   \
 357                                                                         \
 358         write_cr3(efi_scratch.prev_cr3);                                \
 359         __flush_tlb_all();                                              \
 360         local_irq_restore(flags);                                       \
 361                                                                         \
 362         __s;                                                            \
 363 })
 364
 365 efi_status_t efi_thunk_set_virtual_address_map(
 366         void *phys_set_virtual_address_map,
 367         unsigned long memory_map_size,
 368         unsigned long descriptor_size,
 369         u32 descriptor_version,
 370         efi_memory_desc_t *virtual_map)
 371 {
 372         efi_status_t status;
 373         unsigned long flags;
 374         u32 func;
 375
 376         efi_sync_low_kernel_mappings();
 377         local_irq_save(flags);
 378
 379         efi_scratch.prev_cr3 = read_cr3();
 380         write_cr3((unsigned long)efi_scratch.efi_pgt);
 381         __flush_tlb_all();
 382
 383         func = (u32)(unsigned long)phys_set_virtual_address_map;
 384         status = efi64_thunk(func, memory_map_size, descriptor_size,
 385                              descriptor_version, virtual_map);
 386
 387         write_cr3(efi_scratch.prev_cr3);
 388         __flush_tlb_all();
 389         local_irq_restore(flags);
 390
 391         return status;
 392 }
 393
 394 static efi_status_t efi_thunk_get_time(efi_time_t *tm, efi_time_cap_t *tc)
 395 {
 396         efi_status_t status;
 397         u32 phys_tm, phys_tc;
 398
 399         spin_lock(&rtc_lock);
 400
 401         phys_tm = virt_to_phys(tm);
 402         phys_tc = virt_to_phys(tc);
 403
 404         status = efi_thunk(get_time, phys_tm, phys_tc);
 405
 406         spin_unlock(&rtc_lock);
 407
 408         return status;
 409 }
 410
 411 static efi_status_t efi_thunk_set_time(efi_time_t *tm)
 412 {
 413         efi_status_t status;
 414         u32 phys_tm;
 415
 416         spin_lock(&rtc_lock);
 417
 418         phys_tm = virt_to_phys(tm);
 419
 420         status = efi_thunk(set_time, phys_tm);
 421
 422         spin_unlock(&rtc_lock);
 423
 424         return status;
 425 }
 426
 427 static efi_status_t
 428 efi_thunk_get_wakeup_time(efi_bool_t *enabled, efi_bool_t *pending,
 429                           efi_time_t *tm)
 430 {
 431         efi_status_t status;
 432         u32 phys_enabled, phys_pending, phys_tm;
 433
 434         spin_lock(&rtc_lock);
 435
 436         phys_enabled = virt_to_phys(enabled);
 437         phys_pending = virt_to_phys(pending);
 438         phys_tm = virt_to_phys(tm);
 439
 440         status = efi_thunk(get_wakeup_time, phys_enabled,
 441                              phys_pending, phys_tm);
 442
 443         spin_unlock(&rtc_lock);
 444
 445         return status;
 446 }
 447
 448 static efi_status_t
 449 efi_thunk_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm)
 450 {
 451         efi_status_t status;
 452         u32 phys_tm;
 453
 454         spin_lock(&rtc_lock);
 455
 456         phys_tm = virt_to_phys(tm);
 457
 458         status = efi_thunk(set_wakeup_time, enabled, phys_tm);
 459
 460         spin_unlock(&rtc_lock);
 461
 462         return status;
 463 }
 464
 465
 466 static efi_status_t
 467 efi_thunk_get_variable(efi_char16_t *name, efi_guid_t *vendor,
 468                        u32 *attr, unsigned long *data_size, void *data)
 469 {
 470         efi_status_t status;
 471         u32 phys_name, phys_vendor, phys_attr;
 472         u32 phys_data_size, phys_data;
 473
 474         phys_data_size = virt_to_phys(data_size);
 475         phys_vendor = virt_to_phys(vendor);
 476         phys_name = virt_to_phys(name);
 477         phys_attr = virt_to_phys(attr);
 478         phys_data = virt_to_phys(data);
 479
 480         status = efi_thunk(get_variable, phys_name, phys_vendor,
 481                            phys_attr, phys_data_size, phys_data);
 482
 483         return status;
 484 }
 485
 486 static efi_status_t
 487 efi_thunk_set_variable(efi_char16_t *name, efi_guid_t *vendor,
 488                        u32 attr, unsigned long data_size, void *data)
 489 {
 490         u32 phys_name, phys_vendor, phys_data;
 491         efi_status_t status;
 492
 493         phys_name = virt_to_phys(name);
 494         phys_vendor = virt_to_phys(vendor);
 495         phys_data = virt_to_phys(data);
 496
 497         /* If data_size is > sizeof(u32) we've got problems */
 498         status = efi_thunk(set_variable, phys_name, phys_vendor,
 499                            attr, data_size, phys_data);
 500
 501         return status;
 502 }
 503
 504 static efi_status_t
 505 efi_thunk_get_next_variable(unsigned long *name_size,
 506                             efi_char16_t *name,
 507                             efi_guid_t *vendor)
 508 {
 509         efi_status_t status;
 510         u32 phys_name_size, phys_name, phys_vendor;
 511
 512         phys_name_size = virt_to_phys(name_size);
 513         phys_vendor = virt_to_phys(vendor);
 514         phys_name = virt_to_phys(name);
 515
 516         status = efi_thunk(get_next_variable, phys_name_size,
 517                            phys_name, phys_vendor);
 518
 519         return status;
 520 }
 521
 522 static efi_status_t
 523 efi_thunk_get_next_high_mono_count(u32 *count)
 524 {
 525         efi_status_t status;
 526         u32 phys_count;
 527
 528         phys_count = virt_to_phys(count);
 529         status = efi_thunk(get_next_high_mono_count, phys_count);
 530
 531         return status;
 532 }
 533
 534 static void
 535 efi_thunk_reset_system(int reset_type, efi_status_t status,
 536                        unsigned long data_size, efi_char16_t *data)
 537 {
 538         u32 phys_data;
 539
 540         phys_data = virt_to_phys(data);
 541
 542         efi_thunk(reset_system, reset_type, status, data_size, phys_data);
 543 }
 544
 545 static efi_status_t
 546 efi_thunk_update_capsule(efi_capsule_header_t **capsules,
 547                          unsigned long count, unsigned long sg_list)
 548 {
 549         /*
 550          * To properly support this function we would need to repackage
 551          * 'capsules' because the firmware doesn't understand 64-bit
 552          * pointers.
 553          */
 554         return EFI_UNSUPPORTED;
 555 }
 556
 557 static efi_status_t
 558 efi_thunk_query_variable_info(u32 attr, u64 *storage_space,
 559                               u64 *remaining_space,
 560                               u64 *max_variable_size)
 561 {
 562         efi_status_t status;
 563         u32 phys_storage, phys_remaining, phys_max;
 564
 565         if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
 566                 return EFI_UNSUPPORTED;
 567
 568         phys_storage = virt_to_phys(storage_space);
 569         phys_remaining = virt_to_phys(remaining_space);
 570         phys_max = virt_to_phys(max_variable_size);
 571
 572         status = efi_thunk(query_variable_info, attr, phys_storage,
 573                            phys_remaining, phys_max);
 574
 575         return status;
 576 }
 577
 578 static efi_status_t
 579 efi_thunk_query_capsule_caps(efi_capsule_header_t **capsules,
 580                              unsigned long count, u64 *max_size,
 581                              int *reset_type)
 582 {
 583         /*
 584          * To properly support this function we would need to repackage
 585          * 'capsules' because the firmware doesn't understand 64-bit
 586          * pointers.
 587          */
 588         return EFI_UNSUPPORTED;
 589 }
 590
 591 void efi_thunk_runtime_setup(void)
 592 {
 593         efi.get_time = efi_thunk_get_time;
 594         efi.set_time = efi_thunk_set_time;
 595         efi.get_wakeup_time = efi_thunk_get_wakeup_time;
 596         efi.set_wakeup_time = efi_thunk_set_wakeup_time;
 597         efi.get_variable = efi_thunk_get_variable;
 598         efi.get_next_variable = efi_thunk_get_next_variable;
 599         efi.set_variable = efi_thunk_set_variable;
 600         efi.get_next_high_mono_count = efi_thunk_get_next_high_mono_count;
 601         efi.reset_system = efi_thunk_reset_system;
 602         efi.query_variable_info = efi_thunk_query_variable_info;
 603         efi.update_capsule = efi_thunk_update_capsule;
 604         efi.query_capsule_caps = efi_thunk_query_capsule_caps;
 605 }
 606 #endif /* CONFIG_EFI_MIXED */