arch/x86/kernel/head64.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  prepare to run common code
   4  *
   5  *  Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
   6  */
   7
   8 #define DISABLE_BRANCH_PROFILING
   9
  10 /* cpu_feature_enabled() cannot be used this early */
  11 #define USE_EARLY_PGTABLE_L5
  12
  13 #include <linux/init.h>
  14 #include <linux/linkage.h>
  15 #include <linux/types.h>
  16 #include <linux/kernel.h>
  17 #include <linux/string.h>
  18 #include <linux/percpu.h>
  19 #include <linux/start_kernel.h>
  20 #include <linux/io.h>
  21 #include <linux/memblock.h>
  22 #include <linux/mem_encrypt.h>
  23 #include <linux/pgtable.h>
  24
  25 #include <asm/processor.h>
  26 #include <asm/proto.h>
  27 #include <asm/smp.h>
  28 #include <asm/setup.h>
  29 #include <asm/desc.h>
  30 #include <asm/tlbflush.h>
  31 #include <asm/sections.h>
  32 #include <asm/kdebug.h>
  33 #include <asm/e820/api.h>
  34 #include <asm/bios_ebda.h>
  35 #include <asm/bootparam_utils.h>
  36 #include <asm/microcode.h>
  37 #include <asm/kasan.h>
  38 #include <asm/fixmap.h>
  39 #include <asm/realmode.h>
  40 #include <asm/desc.h>
  41 #include <asm/extable.h>
  42 #include <asm/trapnr.h>
  43 #include <asm/sev-es.h>
  44
  45 /*
  46  * Manage page tables very early on.
  47  */
  48 extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD];
  49 static unsigned int __initdata next_early_pgt;
  50 pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX);
  51
  52 #ifdef CONFIG_X86_5LEVEL
  53 unsigned int __pgtable_l5_enabled __ro_after_init;
  54 unsigned int pgdir_shift __ro_after_init = 39;
  55 EXPORT_SYMBOL(pgdir_shift);
  56 unsigned int ptrs_per_p4d __ro_after_init = 1;
  57 EXPORT_SYMBOL(ptrs_per_p4d);
  58 #endif
  59
  60 #ifdef CONFIG_DYNAMIC_MEMORY_LAYOUT
  61 unsigned long page_offset_base __ro_after_init = __PAGE_OFFSET_BASE_L4;
  62 EXPORT_SYMBOL(page_offset_base);
  63 unsigned long vmalloc_base __ro_after_init = __VMALLOC_BASE_L4;
  64 EXPORT_SYMBOL(vmalloc_base);
  65 unsigned long vmemmap_base __ro_after_init = __VMEMMAP_BASE_L4;
  66 EXPORT_SYMBOL(vmemmap_base);
  67 #endif
  68
  69 /*
  70  * GDT used on the boot CPU before switching to virtual addresses.
  71  */
  72 static struct desc_struct startup_gdt[GDT_ENTRIES] = {
  73         [GDT_ENTRY_KERNEL32_CS]         = GDT_ENTRY_INIT(0xc09b, 0, 0xfffff),
  74         [GDT_ENTRY_KERNEL_CS]           = GDT_ENTRY_INIT(0xa09b, 0, 0xfffff),
  75         [GDT_ENTRY_KERNEL_DS]           = GDT_ENTRY_INIT(0xc093, 0, 0xfffff),
  76 };
  77
  78 /*
  79  * Address needs to be set at runtime because it references the startup_gdt
  80  * while the kernel still uses a direct mapping.
  81  */
  82 static struct desc_ptr startup_gdt_descr = {
  83         .size = sizeof(startup_gdt),
  84         .address = 0,
  85 };
  86
  87 #define __head  __section(".head.text")
  88
  89 static void __head *fixup_pointer(void *ptr, unsigned long physaddr)
  90 {
  91         return ptr - (void *)_text + (void *)physaddr;
  92 }
  93
  94 static unsigned long __head *fixup_long(void *ptr, unsigned long physaddr)
  95 {
  96         return fixup_pointer(ptr, physaddr);
  97 }
  98
  99 #ifdef CONFIG_X86_5LEVEL
 100 static unsigned int __head *fixup_int(void *ptr, unsigned long physaddr)
 101 {
 102         return fixup_pointer(ptr, physaddr);
 103 }
 104
 105 static bool __head check_la57_support(unsigned long physaddr)
 106 {
 107         /*
 108          * 5-level paging is detected and enabled at kernel decomression
 109          * stage. Only check if it has been enabled there.
 110          */
 111         if (!(native_read_cr4() & X86_CR4_LA57))
 112                 return false;
 113
 114         *fixup_int(&__pgtable_l5_enabled, physaddr) = 1;
 115         *fixup_int(&pgdir_shift, physaddr) = 48;
 116         *fixup_int(&ptrs_per_p4d, physaddr) = 512;
 117         *fixup_long(&page_offset_base, physaddr) = __PAGE_OFFSET_BASE_L5;
 118         *fixup_long(&vmalloc_base, physaddr) = __VMALLOC_BASE_L5;
 119         *fixup_long(&vmemmap_base, physaddr) = __VMEMMAP_BASE_L5;
 120
 121         return true;
 122 }
 123 #else
 124 static bool __head check_la57_support(unsigned long physaddr)
 125 {
 126         return false;
 127 }
 128 #endif
 129
 130 /* Code in __startup_64() can be relocated during execution, but the compiler
 131  * doesn't have to generate PC-relative relocations when accessing globals from
 132  * that function. Clang actually does not generate them, which leads to
 133  * boot-time crashes. To work around this problem, every global pointer must
 134  * be adjusted using fixup_pointer().
 135  */
 136 unsigned long __head __startup_64(unsigned long physaddr,
 137                                   struct boot_params *bp)
 138 {
 139         unsigned long vaddr, vaddr_end;
 140         unsigned long load_delta, *p;
 141         unsigned long pgtable_flags;
 142         pgdval_t *pgd;
 143         p4dval_t *p4d;
 144         pudval_t *pud;
 145         pmdval_t *pmd, pmd_entry;
 146         pteval_t *mask_ptr;
 147         bool la57;
 148         int i;
 149         unsigned int *next_pgt_ptr;
 150
 151         la57 = check_la57_support(physaddr);
 152
 153         /* Is the address too large? */
 154         if (physaddr >> MAX_PHYSMEM_BITS)
 155                 for (;;);
 156
 157         /*
 158          * Compute the delta between the address I am compiled to run at
 159          * and the address I am actually running at.
 160          */
 161         load_delta = physaddr - (unsigned long)(_text - __START_KERNEL_map);
 162
 163         /* Is the address not 2M aligned? */
 164         if (load_delta & ~PMD_PAGE_MASK)
 165                 for (;;);
 166
 167         /* Activate Secure Memory Encryption (SME) if supported and enabled */
 168         sme_enable(bp);
 169
 170         /* Include the SME encryption mask in the fixup value */
 171         load_delta += sme_get_me_mask();
 172
 173         /* Fixup the physical addresses in the page table */
 174
 175         pgd = fixup_pointer(&early_top_pgt, physaddr);
 176         p = pgd + pgd_index(__START_KERNEL_map);
 177         if (la57)
 178                 *p = (unsigned long)level4_kernel_pgt;
 179         else
 180                 *p = (unsigned long)level3_kernel_pgt;
 181         *p += _PAGE_TABLE_NOENC - __START_KERNEL_map + load_delta;
 182
 183         if (la57) {
 184                 p4d = fixup_pointer(&level4_kernel_pgt, physaddr);
 185                 p4d[511] += load_delta;
 186         }
 187
 188         pud = fixup_pointer(&level3_kernel_pgt, physaddr);
 189         pud[510] += load_delta;
 190         pud[511] += load_delta;
 191
 192         pmd = fixup_pointer(level2_fixmap_pgt, physaddr);
 193         for (i = FIXMAP_PMD_TOP; i > FIXMAP_PMD_TOP - FIXMAP_PMD_NUM; i--)
 194                 pmd[i] += load_delta;
 195
 196         /*
 197          * Set up the identity mapping for the switchover.  These
 198          * entries should *NOT* have the global bit set!  This also
 199          * creates a bunch of nonsense entries but that is fine --
 200          * it avoids problems around wraparound.
 201          */
 202
 203         next_pgt_ptr = fixup_pointer(&next_early_pgt, physaddr);
 204         pud = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++], physaddr);
 205         pmd = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++], physaddr);
 206
 207         pgtable_flags = _KERNPG_TABLE_NOENC + sme_get_me_mask();
 208
 209         if (la57) {
 210                 p4d = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++],
 211                                     physaddr);
 212
 213                 i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
 214                 pgd[i + 0] = (pgdval_t)p4d + pgtable_flags;
 215                 pgd[i + 1] = (pgdval_t)p4d + pgtable_flags;
 216
 217                 i = physaddr >> P4D_SHIFT;
 218                 p4d[(i + 0) % PTRS_PER_P4D] = (pgdval_t)pud + pgtable_flags;
 219                 p4d[(i + 1) % PTRS_PER_P4D] = (pgdval_t)pud + pgtable_flags;
 220         } else {
 221                 i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
 222                 pgd[i + 0] = (pgdval_t)pud + pgtable_flags;
 223                 pgd[i + 1] = (pgdval_t)pud + pgtable_flags;
 224         }
 225
 226         i = physaddr >> PUD_SHIFT;
 227         pud[(i + 0) % PTRS_PER_PUD] = (pudval_t)pmd + pgtable_flags;
 228         pud[(i + 1) % PTRS_PER_PUD] = (pudval_t)pmd + pgtable_flags;
 229
 230         pmd_entry = __PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL;
 231         /* Filter out unsupported __PAGE_KERNEL_* bits: */
 232         mask_ptr = fixup_pointer(&__supported_pte_mask, physaddr);
 233         pmd_entry &= *mask_ptr;
 234         pmd_entry += sme_get_me_mask();
 235         pmd_entry +=  physaddr;
 236
 237         for (i = 0; i < DIV_ROUND_UP(_end - _text, PMD_SIZE); i++) {
 238                 int idx = i + (physaddr >> PMD_SHIFT);
 239
 240                 pmd[idx % PTRS_PER_PMD] = pmd_entry + i * PMD_SIZE;
 241         }
 242
 243         /*
 244          * Fixup the kernel text+data virtual addresses. Note that
 245          * we might write invalid pmds, when the kernel is relocated
 246          * cleanup_highmap() fixes this up along with the mappings
 247          * beyond _end.
 248          *
 249          * Only the region occupied by the kernel image has so far
 250          * been checked against the table of usable memory regions
 251          * provided by the firmware, so invalidate pages outside that
 252          * region. A page table entry that maps to a reserved area of
 253          * memory would allow processor speculation into that area,
 254          * and on some hardware (particularly the UV platform) even
 255          * speculative access to some reserved areas is caught as an
 256          * error, causing the BIOS to halt the system.
 257          */
 258
 259         pmd = fixup_pointer(level2_kernel_pgt, physaddr);
 260
 261         /* invalidate pages before the kernel image */
 262         for (i = 0; i < pmd_index((unsigned long)_text); i++)
 263                 pmd[i] &= ~_PAGE_PRESENT;
 264
 265         /* fixup pages that are part of the kernel image */
 266         for (; i <= pmd_index((unsigned long)_end); i++)
 267                 if (pmd[i] & _PAGE_PRESENT)
 268                         pmd[i] += load_delta;
 269
 270         /* invalidate pages after the kernel image */
 271         for (; i < PTRS_PER_PMD; i++)
 272                 pmd[i] &= ~_PAGE_PRESENT;
 273
 274         /*
 275          * Fixup phys_base - remove the memory encryption mask to obtain
 276          * the true physical address.
 277          */
 278         *fixup_long(&phys_base, physaddr) += load_delta - sme_get_me_mask();
 279
 280         /* Encrypt the kernel and related (if SME is active) */
 281         sme_encrypt_kernel(bp);
 282
 283         /*
 284          * Clear the memory encryption mask from the .bss..decrypted section.
 285          * The bss section will be memset to zero later in the initialization so
 286          * there is no need to zero it after changing the memory encryption
 287          * attribute.
 288          */
 289         if (mem_encrypt_active()) {
 290                 vaddr = (unsigned long)__start_bss_decrypted;
 291                 vaddr_end = (unsigned long)__end_bss_decrypted;
 292                 for (; vaddr < vaddr_end; vaddr += PMD_SIZE) {
 293                         i = pmd_index(vaddr);
 294                         pmd[i] -= sme_get_me_mask();
 295                 }
 296         }
 297
 298         /*
 299          * Return the SME encryption mask (if SME is active) to be used as a
 300          * modifier for the initial pgdir entry programmed into CR3.
 301          */
 302         return sme_get_me_mask();
 303 }
 304
 305 unsigned long __startup_secondary_64(void)
 306 {
 307         /*
 308          * Return the SME encryption mask (if SME is active) to be used as a
 309          * modifier for the initial pgdir entry programmed into CR3.
 310          */
 311         return sme_get_me_mask();
 312 }
 313
 314 /* Wipe all early page tables except for the kernel symbol map */
 315 static void __init reset_early_page_tables(void)
 316 {
 317         memset(early_top_pgt, 0, sizeof(pgd_t)*(PTRS_PER_PGD-1));
 318         next_early_pgt = 0;
 319         write_cr3(__sme_pa_nodebug(early_top_pgt));
 320 }
 321
 322 /* Create a new PMD entry */
 323 bool __init __early_make_pgtable(unsigned long address, pmdval_t pmd)
 324 {
 325         unsigned long physaddr = address - __PAGE_OFFSET;
 326         pgdval_t pgd, *pgd_p;
 327         p4dval_t p4d, *p4d_p;
 328         pudval_t pud, *pud_p;
 329         pmdval_t *pmd_p;
 330
 331         /* Invalid address or early pgt is done ?  */
 332         if (physaddr >= MAXMEM || read_cr3_pa() != __pa_nodebug(early_top_pgt))
 333                 return false;
 334
 335 again:
 336         pgd_p = &early_top_pgt[pgd_index(address)].pgd;
 337         pgd = *pgd_p;
 338
 339         /*
 340          * The use of __START_KERNEL_map rather than __PAGE_OFFSET here is
 341          * critical -- __PAGE_OFFSET would point us back into the dynamic
 342          * range and we might end up looping forever...
 343          */
 344         if (!pgtable_l5_enabled())
 345                 p4d_p = pgd_p;
 346         else if (pgd)
 347                 p4d_p = (p4dval_t *)((pgd & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
 348         else {
 349                 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
 350                         reset_early_page_tables();
 351                         goto again;
 352                 }
 353
 354                 p4d_p = (p4dval_t *)early_dynamic_pgts[next_early_pgt++];
 355                 memset(p4d_p, 0, sizeof(*p4d_p) * PTRS_PER_P4D);
 356                 *pgd_p = (pgdval_t)p4d_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
 357         }
 358         p4d_p += p4d_index(address);
 359         p4d = *p4d_p;
 360
 361         if (p4d)
 362                 pud_p = (pudval_t *)((p4d & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
 363         else {
 364                 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
 365                         reset_early_page_tables();
 366                         goto again;
 367                 }
 368
 369                 pud_p = (pudval_t *)early_dynamic_pgts[next_early_pgt++];
 370                 memset(pud_p, 0, sizeof(*pud_p) * PTRS_PER_PUD);
 371                 *p4d_p = (p4dval_t)pud_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
 372         }
 373         pud_p += pud_index(address);
 374         pud = *pud_p;
 375
 376         if (pud)
 377                 pmd_p = (pmdval_t *)((pud & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
 378         else {
 379                 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
 380                         reset_early_page_tables();
 381                         goto again;
 382                 }
 383
 384                 pmd_p = (pmdval_t *)early_dynamic_pgts[next_early_pgt++];
 385                 memset(pmd_p, 0, sizeof(*pmd_p) * PTRS_PER_PMD);
 386                 *pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
 387         }
 388         pmd_p[pmd_index(address)] = pmd;
 389
 390         return true;
 391 }
 392
 393 static bool __init early_make_pgtable(unsigned long address)
 394 {
 395         unsigned long physaddr = address - __PAGE_OFFSET;
 396         pmdval_t pmd;
 397
 398         pmd = (physaddr & PMD_MASK) + early_pmd_flags;
 399
 400         return __early_make_pgtable(address, pmd);
 401 }
 402
 403 void __init do_early_exception(struct pt_regs *regs, int trapnr)
 404 {
 405         if (trapnr == X86_TRAP_PF &&
 406             early_make_pgtable(native_read_cr2()))
 407                 return;
 408
 409         if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT) &&
 410             trapnr == X86_TRAP_VC && handle_vc_boot_ghcb(regs))
 411                 return;
 412
 413         early_fixup_exception(regs, trapnr);
 414 }
 415
 416 /* Don't add a printk in there. printk relies on the PDA which is not initialized
 417    yet. */
 418 static void __init clear_bss(void)
 419 {
 420         memset(__bss_start, 0,
 421                (unsigned long) __bss_stop - (unsigned long) __bss_start);
 422 }
 423
 424 static unsigned long get_cmd_line_ptr(void)
 425 {
 426         unsigned long cmd_line_ptr = boot_params.hdr.cmd_line_ptr;
 427
 428         cmd_line_ptr |= (u64)boot_params.ext_cmd_line_ptr << 32;
 429
 430         return cmd_line_ptr;
 431 }
 432
 433 static void __init copy_bootdata(char *real_mode_data)
 434 {
 435         char * command_line;
 436         unsigned long cmd_line_ptr;
 437
 438         /*
 439          * If SME is active, this will create decrypted mappings of the
 440          * boot data in advance of the copy operations.
 441          */
 442         sme_map_bootdata(real_mode_data);
 443
 444         memcpy(&boot_params, real_mode_data, sizeof(boot_params));
 445         sanitize_boot_params(&boot_params);
 446         cmd_line_ptr = get_cmd_line_ptr();
 447         if (cmd_line_ptr) {
 448                 command_line = __va(cmd_line_ptr);
 449                 memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
 450         }
 451
 452         /*
 453          * The old boot data is no longer needed and won't be reserved,
 454          * freeing up that memory for use by the system. If SME is active,
 455          * we need to remove the mappings that were created so that the
 456          * memory doesn't remain mapped as decrypted.
 457          */
 458         sme_unmap_bootdata(real_mode_data);
 459 }
 460
 461 asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data)
 462 {
 463         /*
 464          * Build-time sanity checks on the kernel image and module
 465          * area mappings. (these are purely build-time and produce no code)
 466          */
 467         BUILD_BUG_ON(MODULES_VADDR < __START_KERNEL_map);
 468         BUILD_BUG_ON(MODULES_VADDR - __START_KERNEL_map < KERNEL_IMAGE_SIZE);
 469         BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE);
 470         BUILD_BUG_ON((__START_KERNEL_map & ~PMD_MASK) != 0);
 471         BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0);
 472         BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
 473         MAYBE_BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
 474                                 (__START_KERNEL & PGDIR_MASK)));
 475         BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END);
 476
 477         cr4_init_shadow();
 478
 479         /* Kill off the identity-map trampoline */
 480         reset_early_page_tables();
 481
 482         clear_bss();
 483
 484         clear_page(init_top_pgt);
 485
 486         /*
 487          * SME support may update early_pmd_flags to include the memory
 488          * encryption mask, so it needs to be called before anything
 489          * that may generate a page fault.
 490          */
 491         sme_early_init();
 492
 493         kasan_early_init();
 494
 495         idt_setup_early_handler();
 496
 497         copy_bootdata(__va(real_mode_data));
 498
 499         /*
 500          * Load microcode early on BSP.
 501          */
 502         load_ucode_bsp();
 503
 504         /* set init_top_pgt kernel high mapping*/
 505         init_top_pgt[511] = early_top_pgt[511];
 506
 507         x86_64_start_reservations(real_mode_data);
 508 }
 509
 510 void __init x86_64_start_reservations(char *real_mode_data)
 511 {
 512         /* version is always not zero if it is copied */
 513         if (!boot_params.hdr.version)
 514                 copy_bootdata(__va(real_mode_data));
 515
 516         x86_early_init_platform_quirks();
 517
 518         switch (boot_params.hdr.hardware_subarch) {
 519         case X86_SUBARCH_INTEL_MID:
 520                 x86_intel_mid_early_setup();
 521                 break;
 522         default:
 523                 break;
 524         }
 525
 526         start_kernel();
 527 }
 528
 529 /*
 530  * Data structures and code used for IDT setup in head_64.S. The bringup-IDT is
 531  * used until the idt_table takes over. On the boot CPU this happens in
 532  * x86_64_start_kernel(), on secondary CPUs in start_secondary(). In both cases
 533  * this happens in the functions called from head_64.S.
 534  *
 535  * The idt_table can't be used that early because all the code modifying it is
 536  * in idt.c and can be instrumented by tracing or KASAN, which both don't work
 537  * during early CPU bringup. Also the idt_table has the runtime vectors
 538  * configured which require certain CPU state to be setup already (like TSS),
 539  * which also hasn't happened yet in early CPU bringup.
 540  */
 541 static gate_desc bringup_idt_table[NUM_EXCEPTION_VECTORS] __page_aligned_data;
 542
 543 static struct desc_ptr bringup_idt_descr = {
 544         .size           = (NUM_EXCEPTION_VECTORS * sizeof(gate_desc)) - 1,
 545         .address        = 0, /* Set at runtime */
 546 };
 547
 548 static void set_bringup_idt_handler(gate_desc *idt, int n, void *handler)
 549 {
 550 #ifdef CONFIG_AMD_MEM_ENCRYPT
 551         struct idt_data data;
 552         gate_desc desc;
 553
 554         init_idt_data(&data, n, handler);
 555         idt_init_desc(&desc, &data);
 556         native_write_idt_entry(idt, n, &desc);
 557 #endif
 558 }
 559
 560 /* This runs while still in the direct mapping */
 561 static void startup_64_load_idt(unsigned long physbase)
 562 {
 563         struct desc_ptr *desc = fixup_pointer(&bringup_idt_descr, physbase);
 564         gate_desc *idt = fixup_pointer(bringup_idt_table, physbase);
 565
 566
 567         if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) {
 568                 void *handler;
 569
 570                 /* VMM Communication Exception */
 571                 handler = fixup_pointer(vc_no_ghcb, physbase);
 572                 set_bringup_idt_handler(idt, X86_TRAP_VC, handler);
 573         }
 574
 575         desc->address = (unsigned long)idt;
 576         native_load_idt(desc);
 577 }
 578
 579 /* This is used when running on kernel addresses */
 580 void early_setup_idt(void)
 581 {
 582         /* VMM Communication Exception */
 583         if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT))
 584                 set_bringup_idt_handler(bringup_idt_table, X86_TRAP_VC, vc_boot_ghcb);
 585
 586         bringup_idt_descr.address = (unsigned long)bringup_idt_table;
 587         native_load_idt(&bringup_idt_descr);
 588 }
 589
 590 /*
 591  * Setup boot CPU state needed before kernel switches to virtual addresses.
 592  */
 593 void __head startup_64_setup_env(unsigned long physbase)
 594 {
 595         /* Load GDT */
 596         startup_gdt_descr.address = (unsigned long)fixup_pointer(startup_gdt, physbase);
 597         native_load_gdt(&startup_gdt_descr);
 598
 599         /* New GDT is live - reload data segment registers */
 600         asm volatile("movl %%eax, %%ds\n"
 601                      "movl %%eax, %%ss\n"
 602                      "movl %%eax, %%es\n" : : "a"(__KERNEL_DS) : "memory");
 603
 604         startup_64_load_idt(physbase);
 605 }