1 /* -*- linux-c -*- ------------------------------------------------------- * 2 * 3 * Copyright (C) 1991, 1992 Linus Torvalds 4 * Copyright 2007 rPath, Inc. - All Rights Reserved 5 * Copyright 2009 Intel Corporation; author H. Peter Anvin 6 * 7 * This file is part of the Linux kernel, and is made available under 8 * the terms of the GNU General Public License version 2. 9 * 10 * ----------------------------------------------------------------------- */ 11 12 /* 13 * Main module for the real-mode kernel code 14 */ 15 16 #include "boot.h" 17 #include "string.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 * Query the keyboard lock status as given by the BIOS, and 62 * set the keyboard repeat rate to maximum. Unclear why the latter 63 * is done here; this might be possible to kill off as stale code. 64 */ 65 static void keyboard_init(void) 66 { 67 struct biosregs ireg, oreg; 68 initregs(&ireg); 69 70 ireg.ah = 0x02; /* Get keyboard status */ 71 intcall(0x16, &ireg, &oreg); 72 boot_params.kbd_status = oreg.al; 73 74 ireg.ax = 0x0305; /* Set keyboard repeat rate */ 75 intcall(0x16, &ireg, NULL); 76 } 77 78 /* 79 * Get Intel SpeedStep (IST) information. 80 */ 81 static void query_ist(void) 82 { 83 struct biosregs ireg, oreg; 84 85 /* Some older BIOSes apparently crash on this call, so filter 86 it from machines too old to have SpeedStep at all. */ 87 if (cpu.level < 6) 88 return; 89 90 initregs(&ireg); 91 ireg.ax = 0xe980; /* IST Support */ 92 ireg.edx = 0x47534943; /* Request value */ 93 intcall(0x15, &ireg, &oreg); 94 95 boot_params.ist_info.signature = oreg.eax; 96 boot_params.ist_info.command = oreg.ebx; 97 boot_params.ist_info.event = oreg.ecx; 98 boot_params.ist_info.perf_level = oreg.edx; 99 } 100 101 /* 102 * Tell the BIOS what CPU mode we intend to run in. 103 */ 104 static void set_bios_mode(void) 105 { 106 #ifdef CONFIG_X86_64 107 struct biosregs ireg; 108 109 initregs(&ireg); 110 ireg.ax = 0xec00; 111 ireg.bx = 2; 112 intcall(0x15, &ireg, NULL); 113 #endif 114 } 115 116 static void init_heap(void) 117 { 118 char *stack_end; 119 120 if (boot_params.hdr.loadflags & CAN_USE_HEAP) { 121 asm("leal %P1(%%esp),%0" 122 : "=r" (stack_end) : "i" (-STACK_SIZE)); 123 124 heap_end = (char *) 125 ((size_t)boot_params.hdr.heap_end_ptr + 0x200); 126 if (heap_end > stack_end) 127 heap_end = stack_end; 128 } else { 129 /* Boot protocol 2.00 only, no heap available */ 130 puts("WARNING: Ancient bootloader, some functionality " 131 "may be limited!\n"); 132 } 133 } 134 135 void main(void) 136 { 137 /* First, copy the boot header into the "zeropage" */ 138 copy_boot_params(); 139 140 /* Initialize the early-boot console */ 141 console_init(); 142 if (cmdline_find_option_bool("debug")) 143 puts("early console in setup code\n"); 144 145 /* End of heap check */ 146 init_heap(); 147 148 /* Make sure we have all the proper CPU support */ 149 if (validate_cpu()) { 150 puts("Unable to boot - please use a kernel appropriate " 151 "for your CPU.\n"); 152 die(); 153 } 154 155 /* Tell the BIOS what CPU mode we intend to run in. */ 156 set_bios_mode(); 157 158 /* Detect memory layout */ 159 detect_memory(); 160 161 /* Set keyboard repeat rate (why?) and query the lock flags */ 162 keyboard_init(); 163 164 /* Query Intel SpeedStep (IST) information */ 165 query_ist(); 166 167 /* Query APM information */ 168 #if defined(CONFIG_APM) || defined(CONFIG_APM_MODULE) 169 query_apm_bios(); 170 #endif 171 172 /* Query EDD information */ 173 #if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE) 174 query_edd(); 175 #endif 176 177 /* Set the video mode */ 178 set_video(); 179 180 /* Do the last things and invoke protected mode */ 181 go_to_protected_mode(); 182 } 183