1 /* -*- linux-c -*- ------------------------------------------------------- * 2 * 3 * Copyright (C) 1991, 1992 Linus Torvalds 4 * Copyright 2007 rPath, Inc. - All Rights Reserved 5 * 6 * This file is part of the Linux kernel, and is made available under 7 * the terms of the GNU General Public License version 2. 8 * 9 * ----------------------------------------------------------------------- */ 10 11 /* 12 * arch/i386/boot/main.c 13 * 14 * Main module for the real-mode kernel code 15 */ 16 17 #include "boot.h" 18 19 struct boot_params boot_params __attribute__((aligned(16))); 20 21 char *HEAP = _end; 22 char *heap_end = _end; /* Default end of heap = no heap */ 23 24 /* 25 * Copy the header into the boot parameter block. Since this 26 * screws up the old-style command line protocol, adjust by 27 * filling in the new-style command line pointer instead. 28 */ 29 #define OLD_CL_MAGIC 0xA33F 30 #define OLD_CL_ADDRESS 0x20 31 32 static void copy_boot_params(void) 33 { 34 struct old_cmdline { 35 u16 cl_magic; 36 u16 cl_offset; 37 }; 38 const struct old_cmdline * const oldcmd = 39 (const struct old_cmdline *)OLD_CL_ADDRESS; 40 41 BUILD_BUG_ON(sizeof boot_params != 4096); 42 memcpy(&boot_params.hdr, &hdr, sizeof hdr); 43 44 if (!boot_params.hdr.cmd_line_ptr && 45 oldcmd->cl_magic == OLD_CL_MAGIC) { 46 /* Old-style command line protocol. */ 47 u16 cmdline_seg; 48 49 /* Figure out if the command line falls in the region 50 of memory that an old kernel would have copied up 51 to 0x90000... */ 52 if (oldcmd->cl_offset < boot_params.hdr.setup_move_size) 53 cmdline_seg = ds(); 54 else 55 cmdline_seg = 0x9000; 56 57 boot_params.hdr.cmd_line_ptr = 58 (cmdline_seg << 4) + oldcmd->cl_offset; 59 } 60 } 61 62 /* 63 * Set the keyboard repeat rate to maximum. Unclear why this 64 * is done here; this might be possible to kill off as stale code. 65 */ 66 static void keyboard_set_repeat(void) 67 { 68 u16 ax = 0x0305; 69 u16 bx = 0; 70 asm volatile("int $0x16" 71 : "+a" (ax), "+b" (bx) 72 : : "ecx", "edx", "esi", "edi"); 73 } 74 75 /* 76 * Get Intel SpeedStep (IST) information. 77 */ 78 static void query_ist(void) 79 { 80 asm("int $0x15" 81 : "=a" (boot_params.ist_info.signature), 82 "=b" (boot_params.ist_info.command), 83 "=c" (boot_params.ist_info.event), 84 "=d" (boot_params.ist_info.perf_level) 85 : "a" (0x0000e980), /* IST Support */ 86 "d" (0x47534943)); /* Request value */ 87 } 88 89 /* 90 * Tell the BIOS what CPU mode we intend to run in. 91 */ 92 static void set_bios_mode(void) 93 { 94 #ifdef CONFIG_X86_64 95 u32 eax, ebx; 96 97 eax = 0xec00; 98 ebx = 2; 99 asm volatile("int $0x15" 100 : "+a" (eax), "+b" (ebx) 101 : : "ecx", "edx", "esi", "edi"); 102 #endif 103 } 104 105 void main(void) 106 { 107 /* First, copy the boot header into the "zeropage" */ 108 copy_boot_params(); 109 110 /* End of heap check */ 111 if (boot_params.hdr.loadflags & CAN_USE_HEAP) { 112 heap_end = (char *)(boot_params.hdr.heap_end_ptr 113 +0x200-STACK_SIZE); 114 } else { 115 /* Boot protocol 2.00 only, no heap available */ 116 puts("WARNING: Ancient bootloader, some functionality " 117 "may be limited!\n"); 118 } 119 120 /* Make sure we have all the proper CPU support */ 121 if (validate_cpu()) { 122 puts("Unable to boot - please use a kernel appropriate " 123 "for your CPU.\n"); 124 die(); 125 } 126 127 /* Tell the BIOS what CPU mode we intend to run in. */ 128 set_bios_mode(); 129 130 /* Detect memory layout */ 131 detect_memory(); 132 133 /* Set keyboard repeat rate (why?) */ 134 keyboard_set_repeat(); 135 136 /* Set the video mode */ 137 set_video(); 138 139 /* Query MCA information */ 140 query_mca(); 141 142 /* Voyager */ 143 #ifdef CONFIG_X86_VOYAGER 144 query_voyager(); 145 #endif 146 147 /* Query Intel SpeedStep (IST) information */ 148 query_ist(); 149 150 /* Query APM information */ 151 #if defined(CONFIG_APM) || defined(CONFIG_APM_MODULE) 152 query_apm_bios(); 153 #endif 154 155 /* Query EDD information */ 156 #if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE) 157 query_edd(); 158 #endif 159 /* Do the last things and invoke protected mode */ 160 go_to_protected_mode(); 161 } 162