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 15 #include <asm/processor.h> 16 #include <asm/proto.h> 17 #include <asm/smp.h> 18 #include <asm/setup.h> 19 #include <asm/desc.h> 20 #include <asm/pgtable.h> 21 #include <asm/tlbflush.h> 22 #include <asm/sections.h> 23 #include <asm/kdebug.h> 24 #include <asm/e820.h> 25 26 static void __init zap_identity_mappings(void) 27 { 28 pgd_t *pgd = pgd_offset_k(0UL); 29 pgd_clear(pgd); 30 __flush_tlb_all(); 31 } 32 33 /* Don't add a printk in there. printk relies on the PDA which is not initialized 34 yet. */ 35 static void __init clear_bss(void) 36 { 37 memset(__bss_start, 0, 38 (unsigned long) __bss_stop - (unsigned long) __bss_start); 39 } 40 41 static void __init copy_bootdata(char *real_mode_data) 42 { 43 char * command_line; 44 45 memcpy(&boot_params, real_mode_data, sizeof boot_params); 46 if (boot_params.hdr.cmd_line_ptr) { 47 command_line = __va(boot_params.hdr.cmd_line_ptr); 48 memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE); 49 } 50 } 51 52 #define EBDA_ADDR_POINTER 0x40E 53 54 static __init void reserve_ebda(void) 55 { 56 unsigned ebda_addr, ebda_size; 57 58 /* 59 * there is a real-mode segmented pointer pointing to the 60 * 4K EBDA area at 0x40E 61 */ 62 ebda_addr = *(unsigned short *)__va(EBDA_ADDR_POINTER); 63 ebda_addr <<= 4; 64 65 if (!ebda_addr) 66 return; 67 68 ebda_size = *(unsigned short *)__va(ebda_addr); 69 70 /* Round EBDA up to pages */ 71 if (ebda_size == 0) 72 ebda_size = 1; 73 ebda_size <<= 10; 74 ebda_size = round_up(ebda_size + (ebda_addr & ~PAGE_MASK), PAGE_SIZE); 75 if (ebda_size > 64*1024) 76 ebda_size = 64*1024; 77 78 reserve_early(ebda_addr, ebda_addr + ebda_size, "EBDA"); 79 } 80 81 void __init x86_64_start_kernel(char * real_mode_data) 82 { 83 int i; 84 85 /* clear bss before set_intr_gate with early_idt_handler */ 86 clear_bss(); 87 88 /* Make NULL pointers segfault */ 89 zap_identity_mappings(); 90 91 for (i = 0; i < IDT_ENTRIES; i++) { 92 #ifdef CONFIG_EARLY_PRINTK 93 set_intr_gate(i, &early_idt_handlers[i]); 94 #else 95 set_intr_gate(i, early_idt_handler); 96 #endif 97 } 98 load_idt((const struct desc_ptr *)&idt_descr); 99 100 early_printk("Kernel alive\n"); 101 102 for (i = 0; i < NR_CPUS; i++) 103 cpu_pda(i) = &boot_cpu_pda[i]; 104 105 pda_init(0); 106 copy_bootdata(__va(real_mode_data)); 107 108 reserve_early(__pa_symbol(&_text), __pa_symbol(&_end), "TEXT DATA BSS"); 109 110 /* Reserve INITRD */ 111 if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) { 112 unsigned long ramdisk_image = boot_params.hdr.ramdisk_image; 113 unsigned long ramdisk_size = boot_params.hdr.ramdisk_size; 114 unsigned long ramdisk_end = ramdisk_image + ramdisk_size; 115 reserve_early(ramdisk_image, ramdisk_end, "RAMDISK"); 116 } 117 118 reserve_ebda(); 119 120 /* 121 * At this point everything still needed from the boot loader 122 * or BIOS or kernel text should be early reserved or marked not 123 * RAM in e820. All other memory is free game. 124 */ 125 126 start_kernel(); 127 } 128