summaryrefslogtreecommitdiff
path: root/arch/x86/kernel/head64.c
blob: fc5371a7e9d199b85992f1634ad073396ae07ac1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
// SPDX-License-Identifier: GPL-2.0
/*
 *  prepare to run common code
 *
 *  Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
 */

#define DISABLE_BRANCH_PROFILING

/* cpu_feature_enabled() cannot be used this early */
#define USE_EARLY_PGTABLE_L5

#include <linux/init.h>
#include <linux/linkage.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/percpu.h>
#include <linux/start_kernel.h>
#include <linux/io.h>
#include <linux/memblock.h>
#include <linux/cc_platform.h>
#include <linux/pgtable.h>

#include <asm/processor.h>
#include <asm/proto.h>
#include <asm/smp.h>
#include <asm/setup.h>
#include <asm/desc.h>
#include <asm/tlbflush.h>
#include <asm/sections.h>
#include <asm/kdebug.h>
#include <asm/e820/api.h>
#include <asm/bios_ebda.h>
#include <asm/bootparam_utils.h>
#include <asm/microcode.h>
#include <asm/kasan.h>
#include <asm/fixmap.h>
#include <asm/realmode.h>
#include <asm/extable.h>
#include <asm/trapnr.h>
#include <asm/sev.h>

/*
 * Manage page tables very early on.
 */
extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD];
static unsigned int __initdata next_early_pgt;
pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX);

#ifdef CONFIG_X86_5LEVEL
unsigned int __pgtable_l5_enabled __ro_after_init;
unsigned int pgdir_shift __ro_after_init = 39;
EXPORT_SYMBOL(pgdir_shift);
unsigned int ptrs_per_p4d __ro_after_init = 1;
EXPORT_SYMBOL(ptrs_per_p4d);
#endif

#ifdef CONFIG_DYNAMIC_MEMORY_LAYOUT
unsigned long page_offset_base __ro_after_init = __PAGE_OFFSET_BASE_L4;
EXPORT_SYMBOL(page_offset_base);
unsigned long vmalloc_base __ro_after_init = __VMALLOC_BASE_L4;
EXPORT_SYMBOL(vmalloc_base);
unsigned long vmemmap_base __ro_after_init = __VMEMMAP_BASE_L4;
EXPORT_SYMBOL(vmemmap_base);
#endif

/*
 * GDT used on the boot CPU before switching to virtual addresses.
 */
static struct desc_struct startup_gdt[GDT_ENTRIES] = {
	[GDT_ENTRY_KERNEL32_CS]         = GDT_ENTRY_INIT(0xc09b, 0, 0xfffff),
	[GDT_ENTRY_KERNEL_CS]           = GDT_ENTRY_INIT(0xa09b, 0, 0xfffff),
	[GDT_ENTRY_KERNEL_DS]           = GDT_ENTRY_INIT(0xc093, 0, 0xfffff),
};

/*
 * Address needs to be set at runtime because it references the startup_gdt
 * while the kernel still uses a direct mapping.
 */
static struct desc_ptr startup_gdt_descr = {
	.size = sizeof(startup_gdt),
	.address = 0,
};

#define __head	__section(".head.text")

static void __head *fixup_pointer(void *ptr, unsigned long physaddr)
{
	return ptr - (void *)_text + (void *)physaddr;
}

static unsigned long __head *fixup_long(void *ptr, unsigned long physaddr)
{
	return fixup_pointer(ptr, physaddr);
}

#ifdef CONFIG_X86_5LEVEL
static unsigned int __head *fixup_int(void *ptr, unsigned long physaddr)
{
	return fixup_pointer(ptr, physaddr);
}

static bool __head check_la57_support(unsigned long physaddr)
{
	/*
	 * 5-level paging is detected and enabled at kernel decompression
	 * stage. Only check if it has been enabled there.
	 */
	if (!(native_read_cr4() & X86_CR4_LA57))
		return false;

	*fixup_int(&__pgtable_l5_enabled, physaddr) = 1;
	*fixup_int(&pgdir_shift, physaddr) = 48;
	*fixup_int(&ptrs_per_p4d, physaddr) = 512;
	*fixup_long(&page_offset_base, physaddr) = __PAGE_OFFSET_BASE_L5;
	*fixup_long(&vmalloc_base, physaddr) = __VMALLOC_BASE_L5;
	*fixup_long(&vmemmap_base, physaddr) = __VMEMMAP_BASE_L5;

	return true;
}
#else
static bool __head check_la57_support(unsigned long physaddr)
{
	return false;
}
#endif

/* Code in __startup_64() can be relocated during execution, but the compiler
 * doesn't have to generate PC-relative relocations when accessing globals from
 * that function. Clang actually does not generate them, which leads to
 * boot-time crashes. To work around this problem, every global pointer must
 * be adjusted using fixup_pointer().
 */
unsigned long __head __startup_64(unsigned long physaddr,
				  struct boot_params *bp)
{
	unsigned long vaddr, vaddr_end;
	unsigned long load_delta, *p;
	unsigned long pgtable_flags;
	pgdval_t *pgd;
	p4dval_t *p4d;
	pudval_t *pud;
	pmdval_t *pmd, pmd_entry;
	pteval_t *mask_ptr;
	bool la57;
	int i;
	unsigned int *next_pgt_ptr;

	la57 = check_la57_support(physaddr);

	/* Is the address too large? */
	if (physaddr >> MAX_PHYSMEM_BITS)
		for (;;);

	/*
	 * Compute the delta between the address I am compiled to run at
	 * and the address I am actually running at.
	 */
	load_delta = physaddr - (unsigned long)(_text - __START_KERNEL_map);

	/* Is the address not 2M aligned? */
	if (load_delta & ~PMD_PAGE_MASK)
		for (;;);

	/* Activate Secure Memory Encryption (SME) if supported and enabled */
	sme_enable(bp);

	/* Include the SME encryption mask in the fixup value */
	load_delta += sme_get_me_mask();

	/* Fixup the physical addresses in the page table */

	pgd = fixup_pointer(&early_top_pgt, physaddr);
	p = pgd + pgd_index(__START_KERNEL_map);
	if (la57)
		*p = (unsigned long)level4_kernel_pgt;
	else
		*p = (unsigned long)level3_kernel_pgt;
	*p += _PAGE_TABLE_NOENC - __START_KERNEL_map + load_delta;

	if (la57) {
		p4d = fixup_pointer(&level4_kernel_pgt, physaddr);
		p4d[511] += load_delta;
	}

	pud = fixup_pointer(&level3_kernel_pgt, physaddr);
	pud[510] += load_delta;
	pud[511] += load_delta;

	pmd = fixup_pointer(level2_fixmap_pgt, physaddr);
	for (i = FIXMAP_PMD_TOP; i > FIXMAP_PMD_TOP - FIXMAP_PMD_NUM; i--)
		pmd[i] += load_delta;

	/*
	 * Set up the identity mapping for the switchover.  These
	 * entries should *NOT* have the global bit set!  This also
	 * creates a bunch of nonsense entries but that is fine --
	 * it avoids problems around wraparound.
	 */

	next_pgt_ptr = fixup_pointer(&next_early_pgt, physaddr);
	pud = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++], physaddr);
	pmd = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++], physaddr);

	pgtable_flags = _KERNPG_TABLE_NOENC + sme_get_me_mask();

	if (la57) {
		p4d = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++],
				    physaddr);

		i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
		pgd[i + 0] = (pgdval_t)p4d + pgtable_flags;
		pgd[i + 1] = (pgdval_t)p4d + pgtable_flags;

		i = physaddr >> P4D_SHIFT;
		p4d[(i + 0) % PTRS_PER_P4D] = (pgdval_t)pud + pgtable_flags;
		p4d[(i + 1) % PTRS_PER_P4D] = (pgdval_t)pud + pgtable_flags;
	} else {
		i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
		pgd[i + 0] = (pgdval_t)pud + pgtable_flags;
		pgd[i + 1] = (pgdval_t)pud + pgtable_flags;
	}

	i = physaddr >> PUD_SHIFT;
	pud[(i + 0) % PTRS_PER_PUD] = (pudval_t)pmd + pgtable_flags;
	pud[(i + 1) % PTRS_PER_PUD] = (pudval_t)pmd + pgtable_flags;

	pmd_entry = __PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL;
	/* Filter out unsupported __PAGE_KERNEL_* bits: */
	mask_ptr = fixup_pointer(&__supported_pte_mask, physaddr);
	pmd_entry &= *mask_ptr;
	pmd_entry += sme_get_me_mask();
	pmd_entry +=  physaddr;

	for (i = 0; i < DIV_ROUND_UP(_end - _text, PMD_SIZE); i++) {
		int idx = i + (physaddr >> PMD_SHIFT);

		pmd[idx % PTRS_PER_PMD] = pmd_entry + i * PMD_SIZE;
	}

	/*
	 * Fixup the kernel text+data virtual addresses. Note that
	 * we might write invalid pmds, when the kernel is relocated
	 * cleanup_highmap() fixes this up along with the mappings
	 * beyond _end.
	 *
	 * Only the region occupied by the kernel image has so far
	 * been checked against the table of usable memory regions
	 * provided by the firmware, so invalidate pages outside that
	 * region. A page table entry that maps to a reserved area of
	 * memory would allow processor speculation into that area,
	 * and on some hardware (particularly the UV platform) even
	 * speculative access to some reserved areas is caught as an
	 * error, causing the BIOS to halt the system.
	 */

	pmd = fixup_pointer(level2_kernel_pgt, physaddr);

	/* invalidate pages before the kernel image */
	for (i = 0; i < pmd_index((unsigned long)_text); i++)
		pmd[i] &= ~_PAGE_PRESENT;

	/* fixup pages that are part of the kernel image */
	for (; i <= pmd_index((unsigned long)_end); i++)
		if (pmd[i] & _PAGE_PRESENT)
			pmd[i] += load_delta;

	/* invalidate pages after the kernel image */
	for (; i < PTRS_PER_PMD; i++)
		pmd[i] &= ~_PAGE_PRESENT;

	/*
	 * Fixup phys_base - remove the memory encryption mask to obtain
	 * the true physical address.
	 */
	*fixup_long(&phys_base, physaddr) += load_delta - sme_get_me_mask();

	/* Encrypt the kernel and related (if SME is active) */
	sme_encrypt_kernel(bp);

	/*
	 * Clear the memory encryption mask from the .bss..decrypted section.
	 * The bss section will be memset to zero later in the initialization so
	 * there is no need to zero it after changing the memory encryption
	 * attribute.
	 *
	 * This is early code, use an open coded check for SME instead of
	 * using cc_platform_has(). This eliminates worries about removing
	 * instrumentation or checking boot_cpu_data in the cc_platform_has()
	 * function.
	 */
	if (sme_get_me_mask()) {
		vaddr = (unsigned long)__start_bss_decrypted;
		vaddr_end = (unsigned long)__end_bss_decrypted;
		for (; vaddr < vaddr_end; vaddr += PMD_SIZE) {
			i = pmd_index(vaddr);
			pmd[i] -= sme_get_me_mask();
		}
	}

	/*
	 * Return the SME encryption mask (if SME is active) to be used as a
	 * modifier for the initial pgdir entry programmed into CR3.
	 */
	return sme_get_me_mask();
}

unsigned long __startup_secondary_64(void)
{
	/*
	 * Return the SME encryption mask (if SME is active) to be used as a
	 * modifier for the initial pgdir entry programmed into CR3.
	 */
	return sme_get_me_mask();
}

/* Wipe all early page tables except for the kernel symbol map */
static void __init reset_early_page_tables(void)
{
	memset(early_top_pgt, 0, sizeof(pgd_t)*(PTRS_PER_PGD-1));
	next_early_pgt = 0;
	write_cr3(__sme_pa_nodebug(early_top_pgt));
}

/* Create a new PMD entry */
bool __init __early_make_pgtable(unsigned long address, pmdval_t pmd)
{
	unsigned long physaddr = address - __PAGE_OFFSET;
	pgdval_t pgd, *pgd_p;
	p4dval_t p4d, *p4d_p;
	pudval_t pud, *pud_p;
	pmdval_t *pmd_p;

	/* Invalid address or early pgt is done ?  */
	if (physaddr >= MAXMEM || read_cr3_pa() != __pa_nodebug(early_top_pgt))
		return false;

again:
	pgd_p = &early_top_pgt[pgd_index(address)].pgd;
	pgd = *pgd_p;

	/*
	 * The use of __START_KERNEL_map rather than __PAGE_OFFSET here is
	 * critical -- __PAGE_OFFSET would point us back into the dynamic
	 * range and we might end up looping forever...
	 */
	if (!pgtable_l5_enabled())
		p4d_p = pgd_p;
	else if (pgd)
		p4d_p = (p4dval_t *)((pgd & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
	else {
		if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
			reset_early_page_tables();
			goto again;
		}

		p4d_p = (p4dval_t *)early_dynamic_pgts[next_early_pgt++];
		memset(p4d_p, 0, sizeof(*p4d_p) * PTRS_PER_P4D);
		*pgd_p = (pgdval_t)p4d_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
	}
	p4d_p += p4d_index(address);
	p4d = *p4d_p;

	if (p4d)
		pud_p = (pudval_t *)((p4d & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
	else {
		if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
			reset_early_page_tables();
			goto again;
		}

		pud_p = (pudval_t *)early_dynamic_pgts[next_early_pgt++];
		memset(pud_p, 0, sizeof(*pud_p) * PTRS_PER_PUD);
		*p4d_p = (p4dval_t)pud_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
	}
	pud_p += pud_index(address);
	pud = *pud_p;

	if (pud)
		pmd_p = (pmdval_t *)((pud & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
	else {
		if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
			reset_early_page_tables();
			goto again;
		}

		pmd_p = (pmdval_t *)early_dynamic_pgts[next_early_pgt++];
		memset(pmd_p, 0, sizeof(*pmd_p) * PTRS_PER_PMD);
		*pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
	}
	pmd_p[pmd_index(address)] = pmd;

	return true;
}

static bool __init early_make_pgtable(unsigned long address)
{
	unsigned long physaddr = address - __PAGE_OFFSET;
	pmdval_t pmd;

	pmd = (physaddr & PMD_MASK) + early_pmd_flags;

	return __early_make_pgtable(address, pmd);
}

void __init do_early_exception(struct pt_regs *regs, int trapnr)
{
	if (trapnr == X86_TRAP_PF &&
	    early_make_pgtable(native_read_cr2()))
		return;

	if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT) &&
	    trapnr == X86_TRAP_VC && handle_vc_boot_ghcb(regs))
		return;

	early_fixup_exception(regs, trapnr);
}

/* Don't add a printk in there. printk relies on the PDA which is not initialized 
   yet. */
static void __init clear_bss(void)
{
	memset(__bss_start, 0,
	       (unsigned long) __bss_stop - (unsigned long) __bss_start);
}

static unsigned long get_cmd_line_ptr(void)
{
	unsigned long cmd_line_ptr = boot_params.hdr.cmd_line_ptr;

	cmd_line_ptr |= (u64)boot_params.ext_cmd_line_ptr << 32;

	return cmd_line_ptr;
}

static void __init copy_bootdata(char *real_mode_data)
{
	char * command_line;
	unsigned long cmd_line_ptr;

	/*
	 * If SME is active, this will create decrypted mappings of the
	 * boot data in advance of the copy operations.
	 */
	sme_map_bootdata(real_mode_data);

	memcpy(&boot_params, real_mode_data, sizeof(boot_params));
	sanitize_boot_params(&boot_params);
	cmd_line_ptr = get_cmd_line_ptr();
	if (cmd_line_ptr) {
		command_line = __va(cmd_line_ptr);
		memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
	}

	/*
	 * The old boot data is no longer needed and won't be reserved,
	 * freeing up that memory for use by the system. If SME is active,
	 * we need to remove the mappings that were created so that the
	 * memory doesn't remain mapped as decrypted.
	 */
	sme_unmap_bootdata(real_mode_data);
}

asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data)
{
	/*
	 * Build-time sanity checks on the kernel image and module
	 * area mappings. (these are purely build-time and produce no code)
	 */
	BUILD_BUG_ON(MODULES_VADDR < __START_KERNEL_map);
	BUILD_BUG_ON(MODULES_VADDR - __START_KERNEL_map < KERNEL_IMAGE_SIZE);
	BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE);
	BUILD_BUG_ON((__START_KERNEL_map & ~PMD_MASK) != 0);
	BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0);
	BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
	MAYBE_BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
				(__START_KERNEL & PGDIR_MASK)));
	BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END);

	cr4_init_shadow();

	/* Kill off the identity-map trampoline */
	reset_early_page_tables();

	clear_bss();

	clear_page(init_top_pgt);

	/*
	 * SME support may update early_pmd_flags to include the memory
	 * encryption mask, so it needs to be called before anything
	 * that may generate a page fault.
	 */
	sme_early_init();

	kasan_early_init();

	idt_setup_early_handler();

	copy_bootdata(__va(real_mode_data));

	/*
	 * Load microcode early on BSP.
	 */
	load_ucode_bsp();

	/* set init_top_pgt kernel high mapping*/
	init_top_pgt[511] = early_top_pgt[511];

	x86_64_start_reservations(real_mode_data);
}

void __init x86_64_start_reservations(char *real_mode_data)
{
	/* version is always not zero if it is copied */
	if (!boot_params.hdr.version)
		copy_bootdata(__va(real_mode_data));

	x86_early_init_platform_quirks();

	switch (boot_params.hdr.hardware_subarch) {
	case X86_SUBARCH_INTEL_MID:
		x86_intel_mid_early_setup();
		break;
	default:
		break;
	}

	start_kernel();
}

/*
 * Data structures and code used for IDT setup in head_64.S. The bringup-IDT is
 * used until the idt_table takes over. On the boot CPU this happens in
 * x86_64_start_kernel(), on secondary CPUs in start_secondary(). In both cases
 * this happens in the functions called from head_64.S.
 *
 * The idt_table can't be used that early because all the code modifying it is
 * in idt.c and can be instrumented by tracing or KASAN, which both don't work
 * during early CPU bringup. Also the idt_table has the runtime vectors
 * configured which require certain CPU state to be setup already (like TSS),
 * which also hasn't happened yet in early CPU bringup.
 */
static gate_desc bringup_idt_table[NUM_EXCEPTION_VECTORS] __page_aligned_data;

static struct desc_ptr bringup_idt_descr = {
	.size		= (NUM_EXCEPTION_VECTORS * sizeof(gate_desc)) - 1,
	.address	= 0, /* Set at runtime */
};

static void set_bringup_idt_handler(gate_desc *idt, int n, void *handler)
{
#ifdef CONFIG_AMD_MEM_ENCRYPT
	struct idt_data data;
	gate_desc desc;

	init_idt_data(&data, n, handler);
	idt_init_desc(&desc, &data);
	native_write_idt_entry(idt, n, &desc);
#endif
}

/* This runs while still in the direct mapping */
static void startup_64_load_idt(unsigned long physbase)
{
	struct desc_ptr *desc = fixup_pointer(&bringup_idt_descr, physbase);
	gate_desc *idt = fixup_pointer(bringup_idt_table, physbase);


	if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) {
		void *handler;

		/* VMM Communication Exception */
		handler = fixup_pointer(vc_no_ghcb, physbase);
		set_bringup_idt_handler(idt, X86_TRAP_VC, handler);
	}

	desc->address = (unsigned long)idt;
	native_load_idt(desc);
}

/* This is used when running on kernel addresses */
void early_setup_idt(void)
{
	/* VMM Communication Exception */
	if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT))
		set_bringup_idt_handler(bringup_idt_table, X86_TRAP_VC, vc_boot_ghcb);

	bringup_idt_descr.address = (unsigned long)bringup_idt_table;
	native_load_idt(&bringup_idt_descr);
}

/*
 * Setup boot CPU state needed before kernel switches to virtual addresses.
 */
void __head startup_64_setup_env(unsigned long physbase)
{
	/* Load GDT */
	startup_gdt_descr.address = (unsigned long)fixup_pointer(startup_gdt, physbase);
	native_load_gdt(&startup_gdt_descr);

	/* New GDT is live - reload data segment registers */
	asm volatile("movl %%eax, %%ds\n"
		     "movl %%eax, %%ss\n"
		     "movl %%eax, %%es\n" : : "a"(__KERNEL_DS) : "memory");

	startup_64_load_idt(physbase);
}