xref: /openbmc/linux/arch/x86/kernel/head64.c (revision 8fa5723aa7e053d498336b48448b292fc2e0458b)
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 
16 #include <asm/processor.h>
17 #include <asm/proto.h>
18 #include <asm/smp.h>
19 #include <asm/setup.h>
20 #include <asm/desc.h>
21 #include <asm/pgtable.h>
22 #include <asm/tlbflush.h>
23 #include <asm/sections.h>
24 #include <asm/kdebug.h>
25 #include <asm/e820.h>
26 #include <asm/bios_ebda.h>
27 
28 /* boot cpu pda */
29 static struct x8664_pda _boot_cpu_pda __read_mostly;
30 
31 #ifdef CONFIG_SMP
32 /*
33  * We install an empty cpu_pda pointer table to indicate to early users
34  * (numa_set_node) that the cpu_pda pointer table for cpus other than
35  * the boot cpu is not yet setup.
36  */
37 static struct x8664_pda *__cpu_pda[NR_CPUS] __initdata;
38 #else
39 static struct x8664_pda *__cpu_pda[NR_CPUS] __read_mostly;
40 #endif
41 
42 void __init x86_64_init_pda(void)
43 {
44 	_cpu_pda = __cpu_pda;
45 	cpu_pda(0) = &_boot_cpu_pda;
46 	pda_init(0);
47 }
48 
49 static void __init zap_identity_mappings(void)
50 {
51 	pgd_t *pgd = pgd_offset_k(0UL);
52 	pgd_clear(pgd);
53 	__flush_tlb_all();
54 }
55 
56 /* Don't add a printk in there. printk relies on the PDA which is not initialized
57    yet. */
58 static void __init clear_bss(void)
59 {
60 	memset(__bss_start, 0,
61 	       (unsigned long) __bss_stop - (unsigned long) __bss_start);
62 }
63 
64 static void __init copy_bootdata(char *real_mode_data)
65 {
66 	char * command_line;
67 
68 	memcpy(&boot_params, real_mode_data, sizeof boot_params);
69 	if (boot_params.hdr.cmd_line_ptr) {
70 		command_line = __va(boot_params.hdr.cmd_line_ptr);
71 		memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
72 	}
73 }
74 
75 void __init x86_64_start_kernel(char * real_mode_data)
76 {
77 	int i;
78 
79 	/*
80 	 * Build-time sanity checks on the kernel image and module
81 	 * area mappings. (these are purely build-time and produce no code)
82 	 */
83 	BUILD_BUG_ON(MODULES_VADDR < KERNEL_IMAGE_START);
84 	BUILD_BUG_ON(MODULES_VADDR-KERNEL_IMAGE_START < KERNEL_IMAGE_SIZE);
85 	BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE);
86 	BUILD_BUG_ON((KERNEL_IMAGE_START & ~PMD_MASK) != 0);
87 	BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0);
88 	BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
89 	BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
90 				(__START_KERNEL & PGDIR_MASK)));
91 	BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END);
92 
93 	/* clear bss before set_intr_gate with early_idt_handler */
94 	clear_bss();
95 
96 	/* Make NULL pointers segfault */
97 	zap_identity_mappings();
98 
99 	/* Cleanup the over mapped high alias */
100 	cleanup_highmap();
101 
102 	for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) {
103 #ifdef CONFIG_EARLY_PRINTK
104 		set_intr_gate(i, &early_idt_handlers[i]);
105 #else
106 		set_intr_gate(i, early_idt_handler);
107 #endif
108 	}
109 	load_idt((const struct desc_ptr *)&idt_descr);
110 
111 	if (console_loglevel == 10)
112 		early_printk("Kernel alive\n");
113 
114 	x86_64_init_pda();
115 
116 	x86_64_start_reservations(real_mode_data);
117 }
118 
119 void __init x86_64_start_reservations(char *real_mode_data)
120 {
121 	copy_bootdata(__va(real_mode_data));
122 
123 	reserve_early(__pa_symbol(&_text), __pa_symbol(&_end), "TEXT DATA BSS");
124 
125 #ifdef CONFIG_BLK_DEV_INITRD
126 	/* Reserve INITRD */
127 	if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) {
128 		unsigned long ramdisk_image = boot_params.hdr.ramdisk_image;
129 		unsigned long ramdisk_size  = boot_params.hdr.ramdisk_size;
130 		unsigned long ramdisk_end   = ramdisk_image + ramdisk_size;
131 		reserve_early(ramdisk_image, ramdisk_end, "RAMDISK");
132 	}
133 #endif
134 
135 	reserve_ebda_region();
136 
137 	/*
138 	 * At this point everything still needed from the boot loader
139 	 * or BIOS or kernel text should be early reserved or marked not
140 	 * RAM in e820. All other memory is free game.
141 	 */
142 
143 	start_kernel();
144 }
145