aboutsummaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/head64.c
blob: 85126ccbdf6b1e957c231a73378cc1ffe78092e8 (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
/*
 *  prepare to run common code
 *
 *  Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
 */

#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 <asm/processor.h>
#include <asm/proto.h>
#include <asm/smp.h>
#include <asm/setup.h>
#include <asm/desc.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/sections.h>
#include <asm/kdebug.h>
#include <asm/e820.h>
#include <asm/bios_ebda.h>
#include <asm/bootparam_utils.h>
#include <asm/microcode.h>

/*
 * Manage page tables very early on.
 */
extern pgd_t early_level4_pgt[PTRS_PER_PGD];
extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD];
static unsigned int __initdata next_early_pgt = 2;
pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX);

/* Wipe all early page tables except for the kernel symbol map */
static void __init reset_early_page_tables(void)
{
	unsigned long i;

	for (i = 0; i < PTRS_PER_PGD-1; i++)
		early_level4_pgt[i].pgd = 0;

	next_early_pgt = 0;

	write_cr3(__pa(early_level4_pgt));
}

/* Create a new PMD entry */
int __init early_make_pgtable(unsigned long address)
{
	unsigned long physaddr = address - __PAGE_OFFSET;
	unsigned long i;
	pgdval_t pgd, *pgd_p;
	pudval_t pud, *pud_p;
	pmdval_t pmd, *pmd_p;

	/* Invalid address or early pgt is done ?  */
	if (physaddr >= MAXMEM || read_cr3() != __pa(early_level4_pgt))
		return -1;

again:
	pgd_p = &early_level4_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 (pgd)
		pud_p = (pudval_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;
		}

		pud_p = (pudval_t *)early_dynamic_pgts[next_early_pgt++];
		for (i = 0; i < PTRS_PER_PUD; i++)
			pud_p[i] = 0;
		*pgd_p = (pgdval_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++];
		for (i = 0; i < PTRS_PER_PMD; i++)
			pmd_p[i] = 0;
		*pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
	}
	pmd = (physaddr & PMD_MASK) + early_pmd_flags;
	pmd_p[pmd_index(address)] = pmd;

	return 0;
}

/* 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;

	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);
	}
}

asmlinkage void __init x86_64_start_kernel(char * real_mode_data)
{
	int i;

	/*
	 * 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));
	BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
				(__START_KERNEL & PGDIR_MASK)));
	BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END);

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

	/* clear bss before set_intr_gate with early_idt_handler */
	clear_bss();

	for (i = 0; i < NUM_EXCEPTION_VECTORS; i++)
		set_intr_gate(i, early_idt_handlers[i]);
	load_idt((const struct desc_ptr *)&idt_descr);

	copy_bootdata(__va(real_mode_data));

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

	if (console_loglevel == 10)
		early_printk("Kernel alive\n");

	clear_page(init_level4_pgt);
	/* set init_level4_pgt kernel high mapping*/
	init_level4_pgt[511] = early_level4_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));

	reserve_ebda_region();

	start_kernel();
}

Privacy Policy