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 18 struct boot_params boot_params __attribute__((aligned(16))); 19 20 char *HEAP = _end; 21 char *heap_end = _end; /* Default end of heap = no heap */ 22 23 /* 24 * Copy the header into the boot parameter block. Since this 25 * screws up the old-style command line protocol, adjust by 26 * filling in the new-style command line pointer instead. 27 */ 28 29 static void copy_boot_params(void) 30 { 31 struct old_cmdline { 32 u16 cl_magic; 33 u16 cl_offset; 34 }; 35 const struct old_cmdline * const oldcmd = 36 (const struct old_cmdline *)OLD_CL_ADDRESS; 37 38 BUILD_BUG_ON(sizeof boot_params != 4096); 39 memcpy(&boot_params.hdr, &hdr, sizeof hdr); 40 41 if (!boot_params.hdr.cmd_line_ptr && 42 oldcmd->cl_magic == OLD_CL_MAGIC) { 43 /* Old-style command line protocol. */ 44 u16 cmdline_seg; 45 46 /* Figure out if the command line falls in the region 47 of memory that an old kernel would have copied up 48 to 0x90000... */ 49 if (oldcmd->cl_offset < boot_params.hdr.setup_move_size) 50 cmdline_seg = ds(); 51 else 52 cmdline_seg = 0x9000; 53 54 boot_params.hdr.cmd_line_ptr = 55 (cmdline_seg << 4) + oldcmd->cl_offset; 56 } 57 } 58 59 /* 60 * Set the keyboard repeat rate to maximum. Unclear why this 61 * is done here; this might be possible to kill off as stale code. 62 */ 63 static void keyboard_set_repeat(void) 64 { 65 struct biosregs ireg; 66 initregs(&ireg); 67 ireg.ax = 0x0305; 68 intcall(0x16, &ireg, NULL); 69 } 70 71 /* 72 * Get Intel SpeedStep (IST) information. 73 */ 74 static void query_ist(void) 75 { 76 struct biosregs ireg, oreg; 77 78 /* Some older BIOSes apparently crash on this call, so filter 79 it from machines too old to have SpeedStep at all. */ 80 if (cpu.level < 6) 81 return; 82 83 initregs(&ireg); 84 ireg.ax = 0xe980; /* IST Support */ 85 ireg.edx = 0x47534943; /* Request value */ 86 intcall(0x15, &ireg, &oreg); 87 88 boot_params.ist_info.signature = oreg.eax; 89 boot_params.ist_info.command = oreg.ebx; 90 boot_params.ist_info.event = oreg.ecx; 91 boot_params.ist_info.perf_level = oreg.edx; 92 } 93 94 /* 95 * Tell the BIOS what CPU mode we intend to run in. 96 */ 97 static void set_bios_mode(void) 98 { 99 #ifdef CONFIG_X86_64 100 struct biosregs ireg; 101 102 initregs(&ireg); 103 ireg.ax = 0xec00; 104 ireg.bx = 2; 105 intcall(0x15, &ireg, NULL); 106 #endif 107 } 108 109 static void init_heap(void) 110 { 111 char *stack_end; 112 113 if (boot_params.hdr.loadflags & CAN_USE_HEAP) { 114 asm("leal %P1(%%esp),%0" 115 : "=r" (stack_end) : "i" (-STACK_SIZE)); 116 117 heap_end = (char *) 118 ((size_t)boot_params.hdr.heap_end_ptr + 0x200); 119 if (heap_end > stack_end) 120 heap_end = stack_end; 121 } else { 122 /* Boot protocol 2.00 only, no heap available */ 123 puts("WARNING: Ancient bootloader, some functionality " 124 "may be limited!\n"); 125 } 126 } 127 128 void main(void) 129 { 130 /* First, copy the boot header into the "zeropage" */ 131 copy_boot_params(); 132 133 /* End of heap check */ 134 init_heap(); 135 136 /* Make sure we have all the proper CPU support */ 137 if (validate_cpu()) { 138 puts("Unable to boot - please use a kernel appropriate " 139 "for your CPU.\n"); 140 die(); 141 } 142 143 /* Tell the BIOS what CPU mode we intend to run in. */ 144 set_bios_mode(); 145 146 /* Detect memory layout */ 147 detect_memory(); 148 149 /* Set keyboard repeat rate (why?) */ 150 keyboard_set_repeat(); 151 152 /* Query MCA information */ 153 query_mca(); 154 155 /* Query Intel SpeedStep (IST) information */ 156 query_ist(); 157 158 /* Query APM information */ 159 #if defined(CONFIG_APM) || defined(CONFIG_APM_MODULE) 160 query_apm_bios(); 161 #endif 162 163 /* Query EDD information */ 164 #if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE) 165 query_edd(); 166 #endif 167 168 /* Set the video mode */ 169 set_video(); 170 171 /* Parse command line for 'quiet' and pass it to decompressor. */ 172 if (cmdline_find_option_bool("quiet")) 173 boot_params.hdr.loadflags |= QUIET_FLAG; 174 175 /* Do the last things and invoke protected mode */ 176 go_to_protected_mode(); 177 } 178