1 // SPDX-License-Identifier: GPL-2.0-only 1
2 /* -*- linux-c -*- ---------------------------
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 * Copyright 2007 rPath, Inc. - All Rights R
6 * Copyright 2009 Intel Corporation; author
7 *
8 * -------------------------------------------
9
10 /*
11 * Main module for the real-mode kernel code
12 */
13 #include <linux/build_bug.h>
14
15 #include "boot.h"
16 #include "string.h"
17
18 struct boot_params boot_params __attribute__((
19
20 struct port_io_ops pio_ops;
21
22 char *HEAP = _end;
23 char *heap_end = _end; /* Default end
24
25 /*
26 * Copy the header into the boot parameter blo
27 * screws up the old-style command line protoc
28 * filling in the new-style command line point
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 oldcm
37
38 BUILD_BUG_ON(sizeof(boot_params) != 40
39 memcpy(&boot_params.hdr, &hdr, sizeof(
40
41 if (!boot_params.hdr.cmd_line_ptr && o
42 /* Old-style command line prot
43 u16 cmdline_seg;
44
45 /*
46 * Figure out if the command l
47 * of memory that an old kerne
48 * to 0x90000...
49 */
50 if (oldcmd->cl_offset < boot_p
51 cmdline_seg = ds();
52 else
53 cmdline_seg = 0x9000;
54
55 boot_params.hdr.cmd_line_ptr =
56 }
57 }
58
59 /*
60 * Query the keyboard lock status as given by
61 * set the keyboard repeat rate to maximum. U
62 * is done here; this might be possible to kil
63 */
64 static void keyboard_init(void)
65 {
66 struct biosregs ireg, oreg;
67
68 initregs(&ireg);
69
70 ireg.ah = 0x02; /* Get keyboar
71 intcall(0x16, &ireg, &oreg);
72 boot_params.kbd_status = oreg.al;
73
74 ireg.ax = 0x0305; /* Set keyboar
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 /*
86 * Some older BIOSes apparently crash
87 * it from machines too old to have Sp
88 */
89 if (cpu.level < 6)
90 return;
91
92 initregs(&ireg);
93 ireg.ax = 0xe980; /* IST Suppor
94 ireg.edx = 0x47534943; /* Request va
95 intcall(0x15, &ireg, &oreg);
96
97 boot_params.ist_info.signature = oreg
98 boot_params.ist_info.command = oreg
99 boot_params.ist_info.event = oreg
100 boot_params.ist_info.perf_level = oreg
101 }
102
103 /*
104 * Tell the BIOS what CPU mode we intend to ru
105 */
106 static void set_bios_mode(void)
107 {
108 #ifdef CONFIG_X86_64
109 struct biosregs ireg;
110
111 initregs(&ireg);
112 ireg.ax = 0xec00;
113 ireg.bx = 2;
114 intcall(0x15, &ireg, NULL);
115 #endif
116 }
117
118 static void init_heap(void)
119 {
120 char *stack_end;
121
122 if (boot_params.hdr.loadflags & CAN_US
123 stack_end = (char *) (current_
124 heap_end = (char *) ((size_t)b
125 if (heap_end > stack_end)
126 heap_end = stack_end;
127 } else {
128 /* Boot protocol 2.00 only, no
129 puts("WARNING: Ancient bootloa
130 }
131 }
132
133 void main(void)
134 {
135 init_default_io_ops();
136
137 /* First, copy the boot header into th
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 c
144
145 /* End of heap check */
146 init_heap();
147
148 /* Make sure we have all the proper CP
149 if (validate_cpu()) {
150 puts("Unable to boot - please
151 die();
152 }
153
154 /* Tell the BIOS what CPU mode we inte
155 set_bios_mode();
156
157 /* Detect memory layout */
158 detect_memory();
159
160 /* Set keyboard repeat rate (why?) and
161 keyboard_init();
162
163 /* Query Intel SpeedStep (IST) informa
164 query_ist();
165
166 /* Query APM information */
167 #if defined(CONFIG_APM) || defined(CONFIG_APM_
168 query_apm_bios();
169 #endif
170
171 /* Query EDD information */
172 #if defined(CONFIG_EDD) || defined(CONFIG_EDD_
173 query_edd();
174 #endif
175
176 /* Set the video mode */
177 set_video();
178
179 /* Do the last things and invoke prote
180 go_to_protected_mode();
181 }
182
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