diff options
Diffstat (limited to 'arch/x86/boot/main.c')
| -rw-r--r-- | arch/x86/boot/main.c | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/arch/x86/boot/main.c b/arch/x86/boot/main.c new file mode 100644 index 000000000000..0eeef3989a17 --- /dev/null +++ b/arch/x86/boot/main.c @@ -0,0 +1,161 @@ +/* -*- linux-c -*- ------------------------------------------------------- * + * + * Copyright (C) 1991, 1992 Linus Torvalds + * Copyright 2007 rPath, Inc. - All Rights Reserved + * + * This file is part of the Linux kernel, and is made available under + * the terms of the GNU General Public License version 2. + * + * ----------------------------------------------------------------------- */ + +/* + * arch/i386/boot/main.c + * + * Main module for the real-mode kernel code + */ + +#include "boot.h" + +struct boot_params boot_params __attribute__((aligned(16))); + +char *HEAP = _end; +char *heap_end = _end; /* Default end of heap = no heap */ + +/* + * Copy the header into the boot parameter block. Since this + * screws up the old-style command line protocol, adjust by + * filling in the new-style command line pointer instead. + */ +#define OLD_CL_MAGIC 0xA33F +#define OLD_CL_ADDRESS 0x20 + +static void copy_boot_params(void) +{ + struct old_cmdline { + u16 cl_magic; + u16 cl_offset; + }; + const struct old_cmdline * const oldcmd = + (const struct old_cmdline *)OLD_CL_ADDRESS; + + BUILD_BUG_ON(sizeof boot_params != 4096); + memcpy(&boot_params.hdr, &hdr, sizeof hdr); + + if (!boot_params.hdr.cmd_line_ptr && + oldcmd->cl_magic == OLD_CL_MAGIC) { + /* Old-style command line protocol. */ + u16 cmdline_seg; + + /* Figure out if the command line falls in the region + of memory that an old kernel would have copied up + to 0x90000... */ + if (oldcmd->cl_offset < boot_params.hdr.setup_move_size) + cmdline_seg = ds(); + else + cmdline_seg = 0x9000; + + boot_params.hdr.cmd_line_ptr = + (cmdline_seg << 4) + oldcmd->cl_offset; + } +} + +/* + * Set the keyboard repeat rate to maximum. Unclear why this + * is done here; this might be possible to kill off as stale code. + */ +static void keyboard_set_repeat(void) +{ + u16 ax = 0x0305; + u16 bx = 0; + asm volatile("int $0x16" + : "+a" (ax), "+b" (bx) + : : "ecx", "edx", "esi", "edi"); +} + +/* + * Get Intel SpeedStep (IST) information. + */ +static void query_ist(void) +{ + asm("int $0x15" + : "=a" (boot_params.ist_info.signature), + "=b" (boot_params.ist_info.command), + "=c" (boot_params.ist_info.event), + "=d" (boot_params.ist_info.perf_level) + : "a" (0x0000e980), /* IST Support */ + "d" (0x47534943)); /* Request value */ +} + +/* + * Tell the BIOS what CPU mode we intend to run in. + */ +static void set_bios_mode(void) +{ +#ifdef CONFIG_X86_64 + u32 eax, ebx; + + eax = 0xec00; + ebx = 2; + asm volatile("int $0x15" + : "+a" (eax), "+b" (ebx) + : : "ecx", "edx", "esi", "edi"); +#endif +} + +void main(void) +{ + /* First, copy the boot header into the "zeropage" */ + copy_boot_params(); + + /* End of heap check */ + if (boot_params.hdr.loadflags & CAN_USE_HEAP) { + heap_end = (char *)(boot_params.hdr.heap_end_ptr + +0x200-STACK_SIZE); + } else { + /* Boot protocol 2.00 only, no heap available */ + puts("WARNING: Ancient bootloader, some functionality " + "may be limited!\n"); + } + + /* Make sure we have all the proper CPU support */ + if (validate_cpu()) { + puts("Unable to boot - please use a kernel appropriate " + "for your CPU.\n"); + die(); + } + + /* Tell the BIOS what CPU mode we intend to run in. */ + set_bios_mode(); + + /* Detect memory layout */ + detect_memory(); + + /* Set keyboard repeat rate (why?) */ + keyboard_set_repeat(); + + /* Set the video mode */ + set_video(); + + /* Query MCA information */ + query_mca(); + + /* Voyager */ +#ifdef CONFIG_X86_VOYAGER + query_voyager(); +#endif + + /* Query Intel SpeedStep (IST) information */ + query_ist(); + + /* Query APM information */ +#if defined(CONFIG_APM) || defined(CONFIG_APM_MODULE) + query_apm_bios(); +#endif + + /* Query EDD information */ +#if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE) + query_edd(); +#endif + /* Do the last things and invoke protected mode */ + go_to_protected_mode(); +} |