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 30 static void copy_boot_params(void) 31 { 32 struct old_cmdline { 33 u16 cl_magic; 34 u16 cl_offset; 35 }; 36 const struct old_cmdline * const oldcmd = 37 (const struct old_cmdline *)OLD_CL_ADDRESS; 38 39 BUILD_BUG_ON(sizeof boot_params != 4096); 40 memcpy(&boot_params.hdr, &hdr, sizeof hdr); 41 42 if (!boot_params.hdr.cmd_line_ptr && 43 oldcmd->cl_magic == OLD_CL_MAGIC) { 44 /* Old-style command line protocol. */ 45 u16 cmdline_seg; 46 47 /* Figure out if the command line falls in the region 48 of memory that an old kernel would have copied up 49 to 0x90000... */ 50 if (oldcmd->cl_offset < boot_params.hdr.setup_move_size) 51 cmdline_seg = ds(); 52 else 53 cmdline_seg = 0x9000; 54 55 boot_params.hdr.cmd_line_ptr = 56 (cmdline_seg << 4) + oldcmd->cl_offset; 57 } 58 } 59 60 /* 61 * Set the keyboard repeat rate to maximum. Unclear why this 62 * is done here; this might be possible to kill off as stale code. 63 */ 64 static void keyboard_set_repeat(void) 65 { 66 u16 ax = 0x0305; 67 u16 bx = 0; 68 asm volatile("int $0x16" 69 : "+a" (ax), "+b" (bx) 70 : : "ecx", "edx", "esi", "edi"); 71 } 72 73 /* 74 * Get Intel SpeedStep (IST) information. 75 */ 76 static void query_ist(void) 77 { 78 asm("int $0x15" 79 : "=a" (boot_params.ist_info.signature), 80 "=b" (boot_params.ist_info.command), 81 "=c" (boot_params.ist_info.event), 82 "=d" (boot_params.ist_info.perf_level) 83 : "a" (0x0000e980), /* IST Support */ 84 "d" (0x47534943)); /* Request value */ 85 } 86 87 /* 88 * Tell the BIOS what CPU mode we intend to run in. 89 */ 90 static void set_bios_mode(void) 91 { 92 #ifdef CONFIG_X86_64 93 u32 eax, ebx; 94 95 eax = 0xec00; 96 ebx = 2; 97 asm volatile("int $0x15" 98 : "+a" (eax), "+b" (ebx) 99 : : "ecx", "edx", "esi", "edi"); 100 #endif 101 } 102 103 static void init_heap(void) 104 { 105 char *stack_end; 106 107 if (boot_params.hdr.loadflags & CAN_USE_HEAP) { 108 asm("leal %P1(%%esp),%0" 109 : "=r" (stack_end) : "i" (-STACK_SIZE)); 110 111 heap_end = (char *) 112 ((size_t)boot_params.hdr.heap_end_ptr + 0x200); 113 if (heap_end > stack_end) 114 heap_end = stack_end; 115 } else { 116 /* Boot protocol 2.00 only, no heap available */ 117 puts("WARNING: Ancient bootloader, some functionality " 118 "may be limited!\n"); 119 } 120 } 121 122 void main(void) 123 { 124 /* First, copy the boot header into the "zeropage" */ 125 copy_boot_params(); 126 127 /* End of heap check */ 128 init_heap(); 129 130 /* Make sure we have all the proper CPU support */ 131 if (validate_cpu()) { 132 puts("Unable to boot - please use a kernel appropriate " 133 "for your CPU.\n"); 134 die(); 135 } 136 137 /* Tell the BIOS what CPU mode we intend to run in. */ 138 set_bios_mode(); 139 140 /* Detect memory layout */ 141 detect_memory(); 142 143 /* Set keyboard repeat rate (why?) */ 144 keyboard_set_repeat(); 145 146 /* Query MCA information */ 147 query_mca(); 148 149 /* Voyager */ 150 #ifdef CONFIG_X86_VOYAGER 151 query_voyager(); 152 #endif 153 154 /* Query Intel SpeedStep (IST) information */ 155 query_ist(); 156 157 /* Query APM information */ 158 #if defined(CONFIG_APM) || defined(CONFIG_APM_MODULE) 159 query_apm_bios(); 160 #endif 161 162 /* Query EDD information */ 163 #if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE) 164 query_edd(); 165 #endif 166 167 /* Set the video mode */ 168 set_video(); 169 170 /* Do the last things and invoke protected mode */ 171 go_to_protected_mode(); 172 } 173