1/*
2 *  prepare to run common code
3 *
4 *  Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
5 */
6
7#include <linux/init.h>
8#include <linux/linkage.h>
9#include <linux/types.h>
10#include <linux/kernel.h>
11#include <linux/string.h>
12#include <linux/percpu.h>
13#include <linux/start_kernel.h>
14#include <linux/io.h>
15#include <linux/memblock.h>
16
17#include <asm/processor.h>
18#include <asm/proto.h>
19#include <asm/smp.h>
20#include <asm/setup.h>
21#include <asm/desc.h>
22#include <asm/pgtable.h>
23#include <asm/tlbflush.h>
24#include <asm/sections.h>
25#include <asm/kdebug.h>
26#include <asm/e820.h>
27#include <asm/bios_ebda.h>
28#include <asm/bootparam_utils.h>
29#include <asm/microcode.h>
30#include <asm/kasan.h>
31
32/*
33 * Manage page tables very early on.
34 */
35extern pgd_t early_level4_pgt[PTRS_PER_PGD];
36extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD];
37static unsigned int __initdata next_early_pgt = 2;
38pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX);
39
40/* Wipe all early page tables except for the kernel symbol map */
41static void __init reset_early_page_tables(void)
42{
43	unsigned long i;
44
45	for (i = 0; i < PTRS_PER_PGD-1; i++)
46		early_level4_pgt[i].pgd = 0;
47
48	next_early_pgt = 0;
49
50	write_cr3(__pa_nodebug(early_level4_pgt));
51}
52
53/* Create a new PMD entry */
54int __init early_make_pgtable(unsigned long address)
55{
56	unsigned long physaddr = address - __PAGE_OFFSET;
57	unsigned long i;
58	pgdval_t pgd, *pgd_p;
59	pudval_t pud, *pud_p;
60	pmdval_t pmd, *pmd_p;
61
62	/* Invalid address or early pgt is done ?  */
63	if (physaddr >= MAXMEM || read_cr3() != __pa_nodebug(early_level4_pgt))
64		return -1;
65
66again:
67	pgd_p = &early_level4_pgt[pgd_index(address)].pgd;
68	pgd = *pgd_p;
69
70	/*
71	 * The use of __START_KERNEL_map rather than __PAGE_OFFSET here is
72	 * critical -- __PAGE_OFFSET would point us back into the dynamic
73	 * range and we might end up looping forever...
74	 */
75	if (pgd)
76		pud_p = (pudval_t *)((pgd & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
77	else {
78		if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
79			reset_early_page_tables();
80			goto again;
81		}
82
83		pud_p = (pudval_t *)early_dynamic_pgts[next_early_pgt++];
84		for (i = 0; i < PTRS_PER_PUD; i++)
85			pud_p[i] = 0;
86		*pgd_p = (pgdval_t)pud_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
87	}
88	pud_p += pud_index(address);
89	pud = *pud_p;
90
91	if (pud)
92		pmd_p = (pmdval_t *)((pud & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
93	else {
94		if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
95			reset_early_page_tables();
96			goto again;
97		}
98
99		pmd_p = (pmdval_t *)early_dynamic_pgts[next_early_pgt++];
100		for (i = 0; i < PTRS_PER_PMD; i++)
101			pmd_p[i] = 0;
102		*pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
103	}
104	pmd = (physaddr & PMD_MASK) + early_pmd_flags;
105	pmd_p[pmd_index(address)] = pmd;
106
107	return 0;
108}
109
110/* Don't add a printk in there. printk relies on the PDA which is not initialized
111   yet. */
112static void __init clear_bss(void)
113{
114	memset(__bss_start, 0,
115	       (unsigned long) __bss_stop - (unsigned long) __bss_start);
116}
117
118static unsigned long get_cmd_line_ptr(void)
119{
120	unsigned long cmd_line_ptr = boot_params.hdr.cmd_line_ptr;
121
122	cmd_line_ptr |= (u64)boot_params.ext_cmd_line_ptr << 32;
123
124	return cmd_line_ptr;
125}
126
127static void __init copy_bootdata(char *real_mode_data)
128{
129	char * command_line;
130	unsigned long cmd_line_ptr;
131
132	memcpy(&boot_params, real_mode_data, sizeof boot_params);
133	sanitize_boot_params(&boot_params);
134	cmd_line_ptr = get_cmd_line_ptr();
135	if (cmd_line_ptr) {
136		command_line = __va(cmd_line_ptr);
137		memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
138	}
139}
140
141asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data)
142{
143	int i;
144
145	/*
146	 * Build-time sanity checks on the kernel image and module
147	 * area mappings. (these are purely build-time and produce no code)
148	 */
149	BUILD_BUG_ON(MODULES_VADDR < __START_KERNEL_map);
150	BUILD_BUG_ON(MODULES_VADDR - __START_KERNEL_map < KERNEL_IMAGE_SIZE);
151	BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE);
152	BUILD_BUG_ON((__START_KERNEL_map & ~PMD_MASK) != 0);
153	BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0);
154	BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
155	BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
156				(__START_KERNEL & PGDIR_MASK)));
157	BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END);
158
159	cr4_init_shadow();
160
161	/* Kill off the identity-map trampoline */
162	reset_early_page_tables();
163
164	clear_bss();
165
166	clear_page(init_level4_pgt);
167
168	kasan_early_init();
169
170	for (i = 0; i < NUM_EXCEPTION_VECTORS; i++)
171		set_intr_gate(i, early_idt_handler_array[i]);
172	load_idt((const struct desc_ptr *)&idt_descr);
173
174	copy_bootdata(__va(real_mode_data));
175
176	/*
177	 * Load microcode early on BSP.
178	 */
179	load_ucode_bsp();
180
181	/* set init_level4_pgt kernel high mapping*/
182	init_level4_pgt[511] = early_level4_pgt[511];
183
184	x86_64_start_reservations(real_mode_data);
185}
186
187void __init x86_64_start_reservations(char *real_mode_data)
188{
189	/* version is always not zero if it is copied */
190	if (!boot_params.hdr.version)
191		copy_bootdata(__va(real_mode_data));
192
193	reserve_ebda_region();
194
195	start_kernel();
196}
197