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62607313 PA |
1 | /* -*- 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 | /* | |
62607313 PA |
12 | * Main module for the real-mode kernel code |
13 | */ | |
14 | ||
15 | #include "boot.h" | |
16 | ||
17 | struct boot_params boot_params __attribute__((aligned(16))); | |
18 | ||
19 | char *HEAP = _end; | |
20 | char *heap_end = _end; /* Default end of heap = no heap */ | |
21 | ||
22 | /* | |
23 | * Copy the header into the boot parameter block. Since this | |
24 | * screws up the old-style command line protocol, adjust by | |
25 | * filling in the new-style command line pointer instead. | |
26 | */ | |
62607313 PA |
27 | |
28 | static void copy_boot_params(void) | |
29 | { | |
30 | struct old_cmdline { | |
31 | u16 cl_magic; | |
32 | u16 cl_offset; | |
33 | }; | |
34 | const struct old_cmdline * const oldcmd = | |
35 | (const struct old_cmdline *)OLD_CL_ADDRESS; | |
36 | ||
37 | BUILD_BUG_ON(sizeof boot_params != 4096); | |
38 | memcpy(&boot_params.hdr, &hdr, sizeof hdr); | |
39 | ||
40 | if (!boot_params.hdr.cmd_line_ptr && | |
41 | oldcmd->cl_magic == OLD_CL_MAGIC) { | |
42 | /* Old-style command line protocol. */ | |
43 | u16 cmdline_seg; | |
44 | ||
45 | /* Figure out if the command line falls in the region | |
46 | of memory that an old kernel would have copied up | |
47 | to 0x90000... */ | |
48 | if (oldcmd->cl_offset < boot_params.hdr.setup_move_size) | |
49 | cmdline_seg = ds(); | |
50 | else | |
51 | cmdline_seg = 0x9000; | |
52 | ||
53 | boot_params.hdr.cmd_line_ptr = | |
54 | (cmdline_seg << 4) + oldcmd->cl_offset; | |
55 | } | |
56 | } | |
57 | ||
58 | /* | |
59 | * Set the keyboard repeat rate to maximum. Unclear why this | |
60 | * is done here; this might be possible to kill off as stale code. | |
61 | */ | |
62 | static void keyboard_set_repeat(void) | |
63 | { | |
64 | u16 ax = 0x0305; | |
65 | u16 bx = 0; | |
66 | asm volatile("int $0x16" | |
67 | : "+a" (ax), "+b" (bx) | |
68 | : : "ecx", "edx", "esi", "edi"); | |
69 | } | |
70 | ||
71 | /* | |
238b706d | 72 | * Get Intel SpeedStep (IST) information. |
62607313 | 73 | */ |
238b706d | 74 | static void query_ist(void) |
62607313 | 75 | { |
c2dcfde8 PA |
76 | /* Some older BIOSes apparently crash on this call, so filter |
77 | it from machines too old to have SpeedStep at all. */ | |
7b27718b JR |
78 | if (cpu.level < 6) |
79 | return; | |
80 | ||
62607313 | 81 | asm("int $0x15" |
238b706d PA |
82 | : "=a" (boot_params.ist_info.signature), |
83 | "=b" (boot_params.ist_info.command), | |
84 | "=c" (boot_params.ist_info.event), | |
85 | "=d" (boot_params.ist_info.perf_level) | |
62607313 PA |
86 | : "a" (0x0000e980), /* IST Support */ |
87 | "d" (0x47534943)); /* Request value */ | |
88 | } | |
89 | ||
90 | /* | |
91 | * Tell the BIOS what CPU mode we intend to run in. | |
92 | */ | |
93 | static void set_bios_mode(void) | |
94 | { | |
95 | #ifdef CONFIG_X86_64 | |
96 | u32 eax, ebx; | |
97 | ||
98 | eax = 0xec00; | |
99 | ebx = 2; | |
100 | asm volatile("int $0x15" | |
101 | : "+a" (eax), "+b" (ebx) | |
102 | : : "ecx", "edx", "esi", "edi"); | |
103 | #endif | |
104 | } | |
105 | ||
acd644bb | 106 | static void init_heap(void) |
62607313 | 107 | { |
acd644bb | 108 | char *stack_end; |
62607313 | 109 | |
62607313 | 110 | if (boot_params.hdr.loadflags & CAN_USE_HEAP) { |
acd644bb PA |
111 | asm("leal %P1(%%esp),%0" |
112 | : "=r" (stack_end) : "i" (-STACK_SIZE)); | |
113 | ||
114 | heap_end = (char *) | |
115 | ((size_t)boot_params.hdr.heap_end_ptr + 0x200); | |
116 | if (heap_end > stack_end) | |
117 | heap_end = stack_end; | |
62607313 PA |
118 | } else { |
119 | /* Boot protocol 2.00 only, no heap available */ | |
120 | puts("WARNING: Ancient bootloader, some functionality " | |
121 | "may be limited!\n"); | |
122 | } | |
acd644bb PA |
123 | } |
124 | ||
125 | void main(void) | |
126 | { | |
127 | /* First, copy the boot header into the "zeropage" */ | |
128 | copy_boot_params(); | |
129 | ||
130 | /* End of heap check */ | |
131 | init_heap(); | |
62607313 PA |
132 | |
133 | /* Make sure we have all the proper CPU support */ | |
134 | if (validate_cpu()) { | |
135 | puts("Unable to boot - please use a kernel appropriate " | |
136 | "for your CPU.\n"); | |
137 | die(); | |
138 | } | |
139 | ||
140 | /* Tell the BIOS what CPU mode we intend to run in. */ | |
141 | set_bios_mode(); | |
142 | ||
143 | /* Detect memory layout */ | |
144 | detect_memory(); | |
145 | ||
146 | /* Set keyboard repeat rate (why?) */ | |
147 | keyboard_set_repeat(); | |
148 | ||
62607313 PA |
149 | /* Query MCA information */ |
150 | query_mca(); | |
151 | ||
238b706d PA |
152 | /* Query Intel SpeedStep (IST) information */ |
153 | query_ist(); | |
62607313 PA |
154 | |
155 | /* Query APM information */ | |
156 | #if defined(CONFIG_APM) || defined(CONFIG_APM_MODULE) | |
157 | query_apm_bios(); | |
158 | #endif | |
159 | ||
160 | /* Query EDD information */ | |
161 | #if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE) | |
162 | query_edd(); | |
163 | #endif | |
1a8514e0 PA |
164 | |
165 | /* Set the video mode */ | |
166 | set_video(); | |
167 | ||
3b6b9293 KH |
168 | /* Parse command line for 'quiet' and pass it to decompressor. */ |
169 | if (cmdline_find_option_bool("quiet")) | |
170 | boot_params.hdr.loadflags |= QUIET_FLAG; | |
171 | ||
62607313 PA |
172 | /* Do the last things and invoke protected mode */ |
173 | go_to_protected_mode(); | |
174 | } |