1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
/* -*- linux-c -*- ------------------------------------------------------- *
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright 2007 rPath, Inc. - All Rights Reserved
* Copyright 2009 Intel Corporation; author H. Peter Anvin
*
* This file is part of the Linux kernel, and is made available under
* the terms of the GNU General Public License version 2.
*
* ----------------------------------------------------------------------- */
/*
* Main module for the real-mode kernel code
*/
#include "boot.h"
#include "string.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.
*/
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;
}
}
/*
* Query the keyboard lock status as given by the BIOS, and
* set the keyboard repeat rate to maximum. Unclear why the latter
* is done here; this might be possible to kill off as stale code.
*/
static void keyboard_init(void)
{
struct biosregs ireg, oreg;
initregs(&ireg);
ireg.ah = 0x02; /* Get keyboard status */
intcall(0x16, &ireg, &oreg);
boot_params.kbd_status = oreg.al;
ireg.ax = 0x0305; /* Set keyboard repeat rate */
intcall(0x16, &ireg, NULL);
}
/*
* Get Intel SpeedStep (IST) information.
*/
static void query_ist(void)
{
struct biosregs ireg, oreg;
/* Some older BIOSes apparently crash on this call, so filter
it from machines too old to have SpeedStep at all. */
if (cpu.level < 6)
return;
initregs(&ireg);
ireg.ax = 0xe980; /* IST Support */
ireg.edx = 0x47534943; /* Request value */
intcall(0x15, &ireg, &oreg);
boot_params.ist_info.signature = oreg.eax;
boot_params.ist_info.command = oreg.ebx;
boot_params.ist_info.event = oreg.ecx;
boot_params.ist_info.perf_level = oreg.edx;
}
/*
* Tell the BIOS what CPU mode we intend to run in.
*/
static void set_bios_mode(void)
{
#ifdef CONFIG_X86_64
struct biosregs ireg;
initregs(&ireg);
ireg.ax = 0xec00;
ireg.bx = 2;
intcall(0x15, &ireg, NULL);
#endif
}
static void init_heap(void)
{
char *stack_end;
if (boot_params.hdr.loadflags & CAN_USE_HEAP) {
asm("leal %P1(%%esp),%0"
: "=r" (stack_end) : "i" (-STACK_SIZE));
heap_end = (char *)
((size_t)boot_params.hdr.heap_end_ptr + 0x200);
if (heap_end > stack_end)
heap_end = stack_end;
} else {
/* Boot protocol 2.00 only, no heap available */
puts("WARNING: Ancient bootloader, some functionality "
"may be limited!\n");
}
}
void main(void)
{
/* First, copy the boot header into the "zeropage" */
copy_boot_params();
/* Initialize the early-boot console */
console_init();
if (cmdline_find_option_bool("debug"))
puts("early console in setup code\n");
/* End of heap check */
init_heap();
/* 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?) and query the lock flags */
keyboard_init();
/* 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
/* Set the video mode */
set_video();
/* Do the last things and invoke protected mode */
go_to_protected_mode();
}
|
