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 <[email protected]> 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/cc_platform.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/extable.h>
  41 #include <asm/trapnr.h>
  42 #include <asm/sev.h>
  43 #include <asm/tdx.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 decompression
 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 static unsigned long __head sme_postprocess_startup(struct boot_params *bp, pmdval_t *pmd)
 131 {
 132         unsigned long vaddr, vaddr_end;
 133         int i;
 134
 135         /* Encrypt the kernel and related (if SME is active) */
 136         sme_encrypt_kernel(bp);
 137
 138         /*
 139          * Clear the memory encryption mask from the .bss..decrypted section.
 140          * The bss section will be memset to zero later in the initialization so
 141          * there is no need to zero it after changing the memory encryption
 142          * attribute.
 143          */
 144         if (sme_get_me_mask()) {
 145                 vaddr = (unsigned long)__start_bss_decrypted;
 146                 vaddr_end = (unsigned long)__end_bss_decrypted;
 147
 148                 for (; vaddr < vaddr_end; vaddr += PMD_SIZE) {
 149                         /*
 150                          * On SNP, transition the page to shared in the RMP table so that
 151                          * it is consistent with the page table attribute change.
 152                          *
 153                          * __start_bss_decrypted has a virtual address in the high range
 154                          * mapping (kernel .text). PVALIDATE, by way of
 155                          * early_snp_set_memory_shared(), requires a valid virtual
 156                          * address but the kernel is currently running off of the identity
 157                          * mapping so use __pa() to get a *currently* valid virtual address.
 158                          */
 159                         early_snp_set_memory_shared(__pa(vaddr), __pa(vaddr), PTRS_PER_PMD);
 160
 161                         i = pmd_index(vaddr);
 162                         pmd[i] -= sme_get_me_mask();
 163                 }
 164         }
 165
 166         /*
 167          * Return the SME encryption mask (if SME is active) to be used as a
 168          * modifier for the initial pgdir entry programmed into CR3.
 169          */
 170         return sme_get_me_mask();
 171 }
 172
 173 /* Code in __startup_64() can be relocated during execution, but the compiler
 174  * doesn't have to generate PC-relative relocations when accessing globals from
 175  * that function. Clang actually does not generate them, which leads to
 176  * boot-time crashes. To work around this problem, every global pointer must
 177  * be adjusted using fixup_pointer().
 178  */
 179 unsigned long __head __startup_64(unsigned long physaddr,
 180                                   struct boot_params *bp)
 181 {
 182         unsigned long load_delta, *p;
 183         unsigned long pgtable_flags;
 184         pgdval_t *pgd;
 185         p4dval_t *p4d;
 186         pudval_t *pud;
 187         pmdval_t *pmd, pmd_entry;
 188         pteval_t *mask_ptr;
 189         bool la57;
 190         int i;
 191         unsigned int *next_pgt_ptr;
 192
 193         la57 = check_la57_support(physaddr);
 194
 195         /* Is the address too large? */
 196         if (physaddr >> MAX_PHYSMEM_BITS)
 197                 for (;;);
 198
 199         /*
 200          * Compute the delta between the address I am compiled to run at
 201          * and the address I am actually running at.
 202          */
 203         load_delta = physaddr - (unsigned long)(_text - __START_KERNEL_map);
 204
 205         /* Is the address not 2M aligned? */
 206         if (load_delta & ~PMD_MASK)
 207                 for (;;);
 208
 209         /* Include the SME encryption mask in the fixup value */
 210         load_delta += sme_get_me_mask();
 211
 212         /* Fixup the physical addresses in the page table */
 213
 214         pgd = fixup_pointer(&early_top_pgt, physaddr);
 215         p = pgd + pgd_index(__START_KERNEL_map);
 216         if (la57)
 217                 *p = (unsigned long)level4_kernel_pgt;
 218         else
 219                 *p = (unsigned long)level3_kernel_pgt;
 220         *p += _PAGE_TABLE_NOENC - __START_KERNEL_map + load_delta;
 221
 222         if (la57) {
 223                 p4d = fixup_pointer(&level4_kernel_pgt, physaddr);
 224                 p4d[511] += load_delta;
 225         }
 226
 227         pud = fixup_pointer(&level3_kernel_pgt, physaddr);
 228         pud[510] += load_delta;
 229         pud[511] += load_delta;
 230
 231         pmd = fixup_pointer(level2_fixmap_pgt, physaddr);
 232         for (i = FIXMAP_PMD_TOP; i > FIXMAP_PMD_TOP - FIXMAP_PMD_NUM; i--)
 233                 pmd[i] += load_delta;
 234
 235         /*
 236          * Set up the identity mapping for the switchover.  These
 237          * entries should *NOT* have the global bit set!  This also
 238          * creates a bunch of nonsense entries but that is fine --
 239          * it avoids problems around wraparound.
 240          */
 241
 242         next_pgt_ptr = fixup_pointer(&next_early_pgt, physaddr);
 243         pud = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++], physaddr);
 244         pmd = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++], physaddr);
 245
 246         pgtable_flags = _KERNPG_TABLE_NOENC + sme_get_me_mask();
 247
 248         if (la57) {
 249                 p4d = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++],
 250                                     physaddr);
 251
 252                 i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
 253                 pgd[i + 0] = (pgdval_t)p4d + pgtable_flags;
 254                 pgd[i + 1] = (pgdval_t)p4d + pgtable_flags;
 255
 256                 i = physaddr >> P4D_SHIFT;
 257                 p4d[(i + 0) % PTRS_PER_P4D] = (pgdval_t)pud + pgtable_flags;
 258                 p4d[(i + 1) % PTRS_PER_P4D] = (pgdval_t)pud + pgtable_flags;
 259         } else {
 260                 i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
 261                 pgd[i + 0] = (pgdval_t)pud + pgtable_flags;
 262                 pgd[i + 1] = (pgdval_t)pud + pgtable_flags;
 263         }
 264
 265         i = physaddr >> PUD_SHIFT;
 266         pud[(i + 0) % PTRS_PER_PUD] = (pudval_t)pmd + pgtable_flags;
 267         pud[(i + 1) % PTRS_PER_PUD] = (pudval_t)pmd + pgtable_flags;
 268
 269         pmd_entry = __PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL;
 270         /* Filter out unsupported __PAGE_KERNEL_* bits: */
 271         mask_ptr = fixup_pointer(&__supported_pte_mask, physaddr);
 272         pmd_entry &= *mask_ptr;
 273         pmd_entry += sme_get_me_mask();
 274         pmd_entry +=  physaddr;
 275
 276         for (i = 0; i < DIV_ROUND_UP(_end - _text, PMD_SIZE); i++) {
 277                 int idx = i + (physaddr >> PMD_SHIFT);
 278
 279                 pmd[idx % PTRS_PER_PMD] = pmd_entry + i * PMD_SIZE;
 280         }
 281
 282         /*
 283          * Fixup the kernel text+data virtual addresses. Note that
 284          * we might write invalid pmds, when the kernel is relocated
 285          * cleanup_highmap() fixes this up along with the mappings
 286          * beyond _end.
 287          *
 288          * Only the region occupied by the kernel image has so far
 289          * been checked against the table of usable memory regions
 290          * provided by the firmware, so invalidate pages outside that
 291          * region. A page table entry that maps to a reserved area of
 292          * memory would allow processor speculation into that area,
 293          * and on some hardware (particularly the UV platform) even
 294          * speculative access to some reserved areas is caught as an
 295          * error, causing the BIOS to halt the system.
 296          */
 297
 298         pmd = fixup_pointer(level2_kernel_pgt, physaddr);
 299
 300         /* invalidate pages before the kernel image */
 301         for (i = 0; i < pmd_index((unsigned long)_text); i++)
 302                 pmd[i] &= ~_PAGE_PRESENT;
 303
 304         /* fixup pages that are part of the kernel image */
 305         for (; i <= pmd_index((unsigned long)_end); i++)
 306                 if (pmd[i] & _PAGE_PRESENT)
 307                         pmd[i] += load_delta;
 308
 309         /* invalidate pages after the kernel image */
 310         for (; i < PTRS_PER_PMD; i++)
 311                 pmd[i] &= ~_PAGE_PRESENT;
 312
 313         /*
 314          * Fixup phys_base - remove the memory encryption mask to obtain
 315          * the true physical address.
 316          */
 317         *fixup_long(&phys_base, physaddr) += load_delta - sme_get_me_mask();
 318
 319         return sme_postprocess_startup(bp, pmd);
 320 }
 321
 322 /* Wipe all early page tables except for the kernel symbol map */
 323 static void __init reset_early_page_tables(void)
 324 {
 325         memset(early_top_pgt, 0, sizeof(pgd_t)*(PTRS_PER_PGD-1));
 326         next_early_pgt = 0;
 327         write_cr3(__sme_pa_nodebug(early_top_pgt));
 328 }
 329
 330 /* Create a new PMD entry */
 331 bool __init __early_make_pgtable(unsigned long address, pmdval_t pmd)
 332 {
 333         unsigned long physaddr = address - __PAGE_OFFSET;
 334         pgdval_t pgd, *pgd_p;
 335         p4dval_t p4d, *p4d_p;
 336         pudval_t pud, *pud_p;
 337         pmdval_t *pmd_p;
 338
 339         /* Invalid address or early pgt is done ?  */
 340         if (physaddr >= MAXMEM || read_cr3_pa() != __pa_nodebug(early_top_pgt))
 341                 return false;
 342
 343 again:
 344         pgd_p = &early_top_pgt[pgd_index(address)].pgd;
 345         pgd = *pgd_p;
 346
 347         /*
 348          * The use of __START_KERNEL_map rather than __PAGE_OFFSET here is
 349          * critical -- __PAGE_OFFSET would point us back into the dynamic
 350          * range and we might end up looping forever...
 351          */
 352         if (!pgtable_l5_enabled())
 353                 p4d_p = pgd_p;
 354         else if (pgd)
 355                 p4d_p = (p4dval_t *)((pgd & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
 356         else {
 357                 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
 358                         reset_early_page_tables();
 359                         goto again;
 360                 }
 361
 362                 p4d_p = (p4dval_t *)early_dynamic_pgts[next_early_pgt++];
 363                 memset(p4d_p, 0, sizeof(*p4d_p) * PTRS_PER_P4D);
 364                 *pgd_p = (pgdval_t)p4d_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
 365         }
 366         p4d_p += p4d_index(address);
 367         p4d = *p4d_p;
 368
 369         if (p4d)
 370                 pud_p = (pudval_t *)((p4d & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
 371         else {
 372                 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
 373                         reset_early_page_tables();
 374                         goto again;
 375                 }
 376
 377                 pud_p = (pudval_t *)early_dynamic_pgts[next_early_pgt++];
 378                 memset(pud_p, 0, sizeof(*pud_p) * PTRS_PER_PUD);
 379                 *p4d_p = (p4dval_t)pud_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
 380         }
 381         pud_p += pud_index(address);
 382         pud = *pud_p;
 383
 384         if (pud)
 385                 pmd_p = (pmdval_t *)((pud & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
 386         else {
 387                 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
 388                         reset_early_page_tables();
 389                         goto again;
 390                 }
 391
 392                 pmd_p = (pmdval_t *)early_dynamic_pgts[next_early_pgt++];
 393                 memset(pmd_p, 0, sizeof(*pmd_p) * PTRS_PER_PMD);
 394                 *pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
 395         }
 396         pmd_p[pmd_index(address)] = pmd;
 397
 398         return true;
 399 }
 400
 401 static bool __init early_make_pgtable(unsigned long address)
 402 {
 403         unsigned long physaddr = address - __PAGE_OFFSET;
 404         pmdval_t pmd;
 405
 406         pmd = (physaddr & PMD_MASK) + early_pmd_flags;
 407
 408         return __early_make_pgtable(address, pmd);
 409 }
 410
 411 void __init do_early_exception(struct pt_regs *regs, int trapnr)
 412 {
 413         if (trapnr == X86_TRAP_PF &&
 414             early_make_pgtable(native_read_cr2()))
 415                 return;
 416
 417         if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT) &&
 418             trapnr == X86_TRAP_VC && handle_vc_boot_ghcb(regs))
 419                 return;
 420
 421         if (trapnr == X86_TRAP_VE && tdx_early_handle_ve(regs))
 422                 return;
 423
 424         early_fixup_exception(regs, trapnr);
 425 }
 426
 427 /* Don't add a printk in there. printk relies on the PDA which is not initialized
 428    yet. */
 429 void __init clear_bss(void)
 430 {
 431         memset(__bss_start, 0,
 432                (unsigned long) __bss_stop - (unsigned long) __bss_start);
 433         memset(__brk_base, 0,
 434                (unsigned long) __brk_limit - (unsigned long) __brk_base);
 435 }
 436
 437 static unsigned long get_cmd_line_ptr(void)
 438 {
 439         unsigned long cmd_line_ptr = boot_params.hdr.cmd_line_ptr;
 440
 441         cmd_line_ptr |= (u64)boot_params.ext_cmd_line_ptr << 32;
 442
 443         return cmd_line_ptr;
 444 }
 445
 446 static void __init copy_bootdata(char *real_mode_data)
 447 {
 448         char * command_line;
 449         unsigned long cmd_line_ptr;
 450
 451         /*
 452          * If SME is active, this will create decrypted mappings of the
 453          * boot data in advance of the copy operations.
 454          */
 455         sme_map_bootdata(real_mode_data);
 456
 457         memcpy(&boot_params, real_mode_data, sizeof(boot_params));
 458         sanitize_boot_params(&boot_params);
 459         cmd_line_ptr = get_cmd_line_ptr();
 460         if (cmd_line_ptr) {
 461                 command_line = __va(cmd_line_ptr);
 462                 memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
 463         }
 464
 465         /*
 466          * The old boot data is no longer needed and won't be reserved,
 467          * freeing up that memory for use by the system. If SME is active,
 468          * we need to remove the mappings that were created so that the
 469          * memory doesn't remain mapped as decrypted.
 470          */
 471         sme_unmap_bootdata(real_mode_data);
 472 }
 473
 474 asmlinkage __visible void __init __noreturn x86_64_start_kernel(char * real_mode_data)
 475 {
 476         /*
 477          * Build-time sanity checks on the kernel image and module
 478          * area mappings. (these are purely build-time and produce no code)
 479          */
 480         BUILD_BUG_ON(MODULES_VADDR < __START_KERNEL_map);
 481         BUILD_BUG_ON(MODULES_VADDR - __START_KERNEL_map < KERNEL_IMAGE_SIZE);
 482         BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE);
 483         BUILD_BUG_ON((__START_KERNEL_map & ~PMD_MASK) != 0);
 484         BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0);
 485         BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
 486         MAYBE_BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
 487                                 (__START_KERNEL & PGDIR_MASK)));
 488         BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END);
 489
 490         cr4_init_shadow();
 491
 492         /* Kill off the identity-map trampoline */
 493         reset_early_page_tables();
 494
 495         clear_bss();
 496
 497         /*
 498          * This needs to happen *before* kasan_early_init() because latter maps stuff
 499          * into that page.
 500          */
 501         clear_page(init_top_pgt);
 502
 503         /*
 504          * SME support may update early_pmd_flags to include the memory
 505          * encryption mask, so it needs to be called before anything
 506          * that may generate a page fault.
 507          */
 508         sme_early_init();
 509
 510         kasan_early_init();
 511
 512         /*
 513          * Flush global TLB entries which could be left over from the trampoline page
 514          * table.
 515          *
 516          * This needs to happen *after* kasan_early_init() as KASAN-enabled .configs
 517          * instrument native_write_cr4() so KASAN must be initialized for that
 518          * instrumentation to work.
 519          */
 520         __native_tlb_flush_global(this_cpu_read(cpu_tlbstate.cr4));
 521
 522         idt_setup_early_handler();
 523
 524         /* Needed before cc_platform_has() can be used for TDX */
 525         tdx_early_init();
 526
 527         copy_bootdata(__va(real_mode_data));
 528
 529         /*
 530          * Load microcode early on BSP.
 531          */
 532         load_ucode_bsp();
 533
 534         /* set init_top_pgt kernel high mapping*/
 535         init_top_pgt[511] = early_top_pgt[511];
 536
 537         x86_64_start_reservations(real_mode_data);
 538 }
 539
 540 void __init __noreturn x86_64_start_reservations(char *real_mode_data)
 541 {
 542         /* version is always not zero if it is copied */
 543         if (!boot_params.hdr.version)
 544                 copy_bootdata(__va(real_mode_data));
 545
 546         x86_early_init_platform_quirks();
 547
 548         switch (boot_params.hdr.hardware_subarch) {
 549         case X86_SUBARCH_INTEL_MID:
 550                 x86_intel_mid_early_setup();
 551                 break;
 552         default:
 553                 break;
 554         }
 555
 556         start_kernel();
 557 }
 558
 559 /*
 560  * Data structures and code used for IDT setup in head_64.S. The bringup-IDT is
 561  * used until the idt_table takes over. On the boot CPU this happens in
 562  * x86_64_start_kernel(), on secondary CPUs in start_secondary(). In both cases
 563  * this happens in the functions called from head_64.S.
 564  *
 565  * The idt_table can't be used that early because all the code modifying it is
 566  * in idt.c and can be instrumented by tracing or KASAN, which both don't work
 567  * during early CPU bringup. Also the idt_table has the runtime vectors
 568  * configured which require certain CPU state to be setup already (like TSS),
 569  * which also hasn't happened yet in early CPU bringup.
 570  */
 571 static gate_desc bringup_idt_table[NUM_EXCEPTION_VECTORS] __page_aligned_data;
 572
 573 static struct desc_ptr bringup_idt_descr = {
 574         .size           = (NUM_EXCEPTION_VECTORS * sizeof(gate_desc)) - 1,
 575         .address        = 0, /* Set at runtime */
 576 };
 577
 578 static void set_bringup_idt_handler(gate_desc *idt, int n, void *handler)
 579 {
 580 #ifdef CONFIG_AMD_MEM_ENCRYPT
 581         struct idt_data data;
 582         gate_desc desc;
 583
 584         init_idt_data(&data, n, handler);
 585         idt_init_desc(&desc, &data);
 586         native_write_idt_entry(idt, n, &desc);
 587 #endif
 588 }
 589
 590 /* This runs while still in the direct mapping */
 591 static void startup_64_load_idt(unsigned long physbase)
 592 {
 593         struct desc_ptr *desc = fixup_pointer(&bringup_idt_descr, physbase);
 594         gate_desc *idt = fixup_pointer(bringup_idt_table, physbase);
 595
 596
 597         if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) {
 598                 void *handler;
 599
 600                 /* VMM Communication Exception */
 601                 handler = fixup_pointer(vc_no_ghcb, physbase);
 602                 set_bringup_idt_handler(idt, X86_TRAP_VC, handler);
 603         }
 604
 605         desc->address = (unsigned long)idt;
 606         native_load_idt(desc);
 607 }
 608
 609 /* This is used when running on kernel addresses */
 610 void early_setup_idt(void)
 611 {
 612         /* VMM Communication Exception */
 613         if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) {
 614                 setup_ghcb();
 615                 set_bringup_idt_handler(bringup_idt_table, X86_TRAP_VC, vc_boot_ghcb);
 616         }
 617
 618         bringup_idt_descr.address = (unsigned long)bringup_idt_table;
 619         native_load_idt(&bringup_idt_descr);
 620 }
 621
 622 /*
 623  * Setup boot CPU state needed before kernel switches to virtual addresses.
 624  */
 625 void __head startup_64_setup_env(unsigned long physbase)
 626 {
 627         /* Load GDT */
 628         startup_gdt_descr.address = (unsigned long)fixup_pointer(startup_gdt, physbase);
 629         native_load_gdt(&startup_gdt_descr);
 630
 631         /* New GDT is live - reload data segment registers */
 632         asm volatile("movl %%eax, %%ds\n"
 633                      "movl %%eax, %%ss\n"
 634                      "movl %%eax, %%es\n" : : "a"(__KERNEL_DS) : "memory");
 635
 636         startup_64_load_idt(physbase);
 637 }