]> Joshua Wise's Git repositories - netwatch.git/blame_incremental - grubload/multiboot_c.c
Avoid suffering from wrong CS_SEGSEL syndrome.
[netwatch.git] / grubload / multiboot_c.c
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CommitLineData
1#include "console.h"
2#include "loader.h"
3#include <output.h>
4#include <minilib.h>
5#include <io.h>
6#include <smram.h>
7#include <multiboot.h>
8#include <smi.h>
9#include <pci.h>
10
11#define INFO_SIGNATURE 0x5754454E
12
13extern char _binary_realmode_bin_start[];
14extern int _binary_realmode_bin_size;
15
16struct info_section
17{
18 unsigned int signature;
19 void (*firstrun)();
20};
21
22void panic(const char *msg)
23{
24 outputf("PANIC: %s\nSystem halted\n", msg);
25 while(1) { __asm__("hlt"); }
26}
27
28void c_start(unsigned int magic, struct mb_info *mbinfo)
29{
30 struct mod_info *mods = mbinfo->mods;
31 smram_state_t old_smramc;
32 struct info_section * info;
33 int i;
34
35 void (*realmode)() = (void (*)()) 0x4000;
36
37 show_cursor();
38 outputf("NetWatch loader");
39
40 if (magic != MULTIBOOT_LOADER_MAGIC)
41 panic("Bootloader was not multiboot compliant; cannot continue.");
42
43 for (i = 0; i < mbinfo->mod_cnt; i++)
44 {
45 outputf("Module found:");
46 outputf(" Start: %08x", (unsigned long) mods[i].mod_start);
47 outputf(" Size: %08x", (unsigned long)mods[i].mod_end - (unsigned long)mods[i].mod_start);
48 outputf(" Name: %s", mods[i].mod_string);
49 }
50
51 if (mbinfo->mod_cnt != 1)
52 panic("Expected exactly one module; cannot continue.");
53 outputf("Current SMRAMC state is: %02x", pci_read8(0, 0, 0, 0x70));
54 outputf("Current USB state is: %04x %04x", pci_read16(0, 31, 2, 0xC0), pci_read16(0, 31, 4, 0xC0));
55 outputf("Current SMI state is: %08x", inl(0x830));
56
57 smi_disable();
58
59 /* Try really hard to shut up USB_LEGKEY. */
60 pci_write16(0, 31, 2, 0xC0, pci_read16(0, 31, 2, 0xC0));
61 pci_write16(0, 31, 2, 0xC0, 0);
62 pci_write16(0, 31, 4, 0xC0, pci_read16(0, 31, 4, 0xC0));
63 pci_write16(0, 31, 4, 0xC0, 0);
64/*
65 pci_bus_enum();
66*/
67 /* Open the SMRAM aperture and load our ELF. */
68 old_smramc = smram_save_state();
69
70 if (smram_aseg_set_state(SMRAM_ASEG_OPEN) != 0)
71 panic("Opening SMRAM failed; cannot load ELF.");
72
73 load_elf(mods[0].mod_start, (unsigned long)mods[0].mod_end - (unsigned long)mods[0].mod_start);
74
75 info = (struct info_section *)0x10000;
76 if (info->signature != INFO_SIGNATURE)
77 {
78 smram_restore_state(old_smramc); /* Restore so that video ram is touchable again. */
79 panic("Info section signature mismatch.");
80 }
81
82 info->firstrun();
83 smram_restore_state(old_smramc);
84
85 outputf("New SMRAMC state is: %02x", pci_read8(0, 0, 0, 0x70));
86
87 puts("Waiting for a bit before returning to real mode...");
88 for (i=0; i<0x500000; i++)
89 {
90 if ((i % 0x100000) == 0)
91 puts(".");
92 inb(0x80);
93 }
94 puts("\n");
95
96 outputf("Now returning to real mode.");
97 memcpy((void *)0x4000, _binary_realmode_bin_start, (int)&_binary_realmode_bin_size);
98 realmode(); // goodbye!
99}
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