blob: 7828da5cfd07475376c7d4d3fc95282334b60a3d [file] [log] [blame]
H. Peter Anvin62607312007-07-11 12:18:54 -07001/* -*- 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
19struct boot_params boot_params __attribute__((aligned(16)));
20
21char *HEAP = _end;
22char *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 */
H. Peter Anvin62607312007-07-11 12:18:54 -070029
30static 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 */
64static 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/*
H. Peter Anvin238b7062007-07-18 17:19:30 -070074 * Get Intel SpeedStep (IST) information.
H. Peter Anvin62607312007-07-11 12:18:54 -070075 */
H. Peter Anvin238b7062007-07-18 17:19:30 -070076static void query_ist(void)
H. Peter Anvin62607312007-07-11 12:18:54 -070077{
78 asm("int $0x15"
H. Peter Anvin238b7062007-07-18 17:19:30 -070079 : "=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)
H. Peter Anvin62607312007-07-11 12:18:54 -070083 : "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 */
90static 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
H. Peter Anvinacd644b2008-01-30 13:33:04 +0100103static 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
H. Peter Anvin62607312007-07-11 12:18:54 -0700122void main(void)
123{
124 /* First, copy the boot header into the "zeropage" */
125 copy_boot_params();
126
127 /* End of heap check */
H. Peter Anvinacd644b2008-01-30 13:33:04 +0100128 init_heap();
H. Peter Anvin62607312007-07-11 12:18:54 -0700129
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
H. Peter Anvin62607312007-07-11 12:18:54 -0700146 /* Query MCA information */
147 query_mca();
148
149 /* Voyager */
150#ifdef CONFIG_X86_VOYAGER
151 query_voyager();
152#endif
153
H. Peter Anvin238b7062007-07-18 17:19:30 -0700154 /* Query Intel SpeedStep (IST) information */
155 query_ist();
H. Peter Anvin62607312007-07-11 12:18:54 -0700156
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
H. Peter Anvin1a8514e2008-01-30 13:33:03 +0100166
167 /* Set the video mode */
168 set_video();
169
H. Peter Anvin62607312007-07-11 12:18:54 -0700170 /* Do the last things and invoke protected mode */
171 go_to_protected_mode();
172}