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97873a3d | 1 | // SPDX-License-Identifier: GPL-2.0-only |
62607313 PA |
2 | /* -*- linux-c -*- ------------------------------------------------------- * |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * Copyright 2007 rPath, Inc. - All Rights Reserved | |
df7699c5 | 6 | * Copyright 2009 Intel Corporation; author H. Peter Anvin |
62607313 | 7 | * |
62607313 PA |
8 | * ----------------------------------------------------------------------- */ |
9 | ||
10 | /* | |
62607313 PA |
11 | * Main module for the real-mode kernel code |
12 | */ | |
d5a1badd | 13 | #include <linux/build_bug.h> |
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14 | |
15 | #include "boot.h" | |
c041b5ad | 16 | #include "string.h" |
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17 | |
18 | struct boot_params boot_params __attribute__((aligned(16))); | |
19 | ||
eb4ea1ae KS |
20 | struct port_io_ops pio_ops; |
21 | ||
62607313 PA |
22 | char *HEAP = _end; |
23 | char *heap_end = _end; /* Default end of heap = no heap */ | |
24 | ||
25 | /* | |
26 | * Copy the header into the boot parameter block. Since this | |
27 | * screws up the old-style command line protocol, adjust by | |
28 | * filling in the new-style command line pointer instead. | |
29 | */ | |
62607313 PA |
30 | static void copy_boot_params(void) |
31 | { | |
32 | struct old_cmdline { | |
33 | u16 cl_magic; | |
34 | u16 cl_offset; | |
35 | }; | |
52cccc64 | 36 | const struct old_cmdline * const oldcmd = absolute_pointer(OLD_CL_ADDRESS); |
62607313 | 37 | |
0e96f31e JB |
38 | BUILD_BUG_ON(sizeof(boot_params) != 4096); |
39 | memcpy(&boot_params.hdr, &hdr, sizeof(hdr)); | |
62607313 | 40 | |
52cccc64 IM |
41 | if (!boot_params.hdr.cmd_line_ptr && oldcmd->cl_magic == OLD_CL_MAGIC) { |
42 | /* Old-style command line protocol */ | |
62607313 PA |
43 | u16 cmdline_seg; |
44 | ||
52cccc64 IM |
45 | /* |
46 | * Figure out if the command line falls in the region | |
47 | * of memory that an old kernel would have copied up | |
48 | * to 0x90000... | |
49 | */ | |
62607313 PA |
50 | if (oldcmd->cl_offset < boot_params.hdr.setup_move_size) |
51 | cmdline_seg = ds(); | |
52 | else | |
53 | cmdline_seg = 0x9000; | |
54 | ||
52cccc64 | 55 | boot_params.hdr.cmd_line_ptr = (cmdline_seg << 4) + oldcmd->cl_offset; |
62607313 PA |
56 | } |
57 | } | |
58 | ||
59 | /* | |
b2d0b7a0 JC |
60 | * Query the keyboard lock status as given by the BIOS, and |
61 | * set the keyboard repeat rate to maximum. Unclear why the latter | |
62607313 PA |
62 | * is done here; this might be possible to kill off as stale code. |
63 | */ | |
b2d0b7a0 | 64 | static void keyboard_init(void) |
62607313 | 65 | { |
b2d0b7a0 | 66 | struct biosregs ireg, oreg; |
52cccc64 | 67 | |
df7699c5 | 68 | initregs(&ireg); |
b2d0b7a0 JC |
69 | |
70 | ireg.ah = 0x02; /* Get keyboard status */ | |
71 | intcall(0x16, &ireg, &oreg); | |
72 | boot_params.kbd_status = oreg.al; | |
73 | ||
74 | ireg.ax = 0x0305; /* Set keyboard repeat rate */ | |
df7699c5 | 75 | intcall(0x16, &ireg, NULL); |
62607313 PA |
76 | } |
77 | ||
78 | /* | |
238b706d | 79 | * Get Intel SpeedStep (IST) information. |
62607313 | 80 | */ |
238b706d | 81 | static void query_ist(void) |
62607313 | 82 | { |
df7699c5 PA |
83 | struct biosregs ireg, oreg; |
84 | ||
52cccc64 IM |
85 | /* |
86 | * Some older BIOSes apparently crash on this call, so filter | |
87 | * it from machines too old to have SpeedStep at all. | |
88 | */ | |
7b27718b JR |
89 | if (cpu.level < 6) |
90 | return; | |
91 | ||
df7699c5 PA |
92 | initregs(&ireg); |
93 | ireg.ax = 0xe980; /* IST Support */ | |
94 | ireg.edx = 0x47534943; /* Request value */ | |
95 | intcall(0x15, &ireg, &oreg); | |
96 | ||
97 | boot_params.ist_info.signature = oreg.eax; | |
98 | boot_params.ist_info.command = oreg.ebx; | |
99 | boot_params.ist_info.event = oreg.ecx; | |
100 | boot_params.ist_info.perf_level = oreg.edx; | |
62607313 PA |
101 | } |
102 | ||
103 | /* | |
104 | * Tell the BIOS what CPU mode we intend to run in. | |
105 | */ | |
106 | static void set_bios_mode(void) | |
107 | { | |
108 | #ifdef CONFIG_X86_64 | |
df7699c5 | 109 | struct biosregs ireg; |
62607313 | 110 | |
df7699c5 PA |
111 | initregs(&ireg); |
112 | ireg.ax = 0xec00; | |
113 | ireg.bx = 2; | |
114 | intcall(0x15, &ireg, NULL); | |
62607313 PA |
115 | #endif |
116 | } | |
117 | ||
acd644bb | 118 | static void init_heap(void) |
62607313 | 119 | { |
acd644bb | 120 | char *stack_end; |
62607313 | 121 | |
62607313 | 122 | if (boot_params.hdr.loadflags & CAN_USE_HEAP) { |
52cccc64 IM |
123 | stack_end = (char *) (current_stack_pointer - STACK_SIZE); |
124 | heap_end = (char *) ((size_t)boot_params.hdr.heap_end_ptr + 0x200); | |
acd644bb PA |
125 | if (heap_end > stack_end) |
126 | heap_end = stack_end; | |
62607313 PA |
127 | } else { |
128 | /* Boot protocol 2.00 only, no heap available */ | |
52cccc64 | 129 | puts("WARNING: Ancient bootloader, some functionality may be limited!\n"); |
62607313 | 130 | } |
acd644bb PA |
131 | } |
132 | ||
133 | void main(void) | |
134 | { | |
eb4ea1ae KS |
135 | init_default_io_ops(); |
136 | ||
acd644bb PA |
137 | /* First, copy the boot header into the "zeropage" */ |
138 | copy_boot_params(); | |
139 | ||
fa97bdf9 PE |
140 | /* Initialize the early-boot console */ |
141 | console_init(); | |
8fee13a4 YL |
142 | if (cmdline_find_option_bool("debug")) |
143 | puts("early console in setup code\n"); | |
fa97bdf9 | 144 | |
acd644bb PA |
145 | /* End of heap check */ |
146 | init_heap(); | |
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147 | |
148 | /* Make sure we have all the proper CPU support */ | |
149 | if (validate_cpu()) { | |
52cccc64 | 150 | puts("Unable to boot - please use a kernel appropriate for your CPU.\n"); |
62607313 PA |
151 | die(); |
152 | } | |
153 | ||
52cccc64 | 154 | /* Tell the BIOS what CPU mode we intend to run in */ |
62607313 PA |
155 | set_bios_mode(); |
156 | ||
157 | /* Detect memory layout */ | |
158 | detect_memory(); | |
159 | ||
b2d0b7a0 JC |
160 | /* Set keyboard repeat rate (why?) and query the lock flags */ |
161 | keyboard_init(); | |
62607313 | 162 | |
238b706d PA |
163 | /* Query Intel SpeedStep (IST) information */ |
164 | query_ist(); | |
62607313 PA |
165 | |
166 | /* Query APM information */ | |
167 | #if defined(CONFIG_APM) || defined(CONFIG_APM_MODULE) | |
168 | query_apm_bios(); | |
169 | #endif | |
170 | ||
171 | /* Query EDD information */ | |
172 | #if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE) | |
173 | query_edd(); | |
174 | #endif | |
1a8514e0 PA |
175 | |
176 | /* Set the video mode */ | |
177 | set_video(); | |
178 | ||
62607313 PA |
179 | /* Do the last things and invoke protected mode */ |
180 | go_to_protected_mode(); | |
181 | } |