put the stack in bss to save space on disk

[netwatch.git] / grubload / multiboot_c.c

diff --git a/grubload/multiboot_c.c b/grubload/multiboot_c.c
index 7c6a4fd11063d350ef055143ab222e1d2e85ca6a..890a003471db280f15a6941821a9d2c04e81b265 100644 (file)
--- a/grubload/multiboot_c.c
+++ b/grubload/multiboot_c.c
@@ -1,6 +1,111 @@
-void c_start(unsigned int magic, void *wee)
+#include "console.h"
+#include <io.h>
+#include <smram.h>
+
+#define INFO_SIGNATURE 0x5754454E
+
+extern char _binary_realmode_bin_start[];
+extern int _binary_realmode_bin_size;
+
+struct mb_info
 {
-       *(unsigned char *)0xB8000 = 'A';
-       while (1)
-               ;
+       unsigned long flags;
+       unsigned long mem_lower, mem_upper;
+       unsigned long boot_dev;
+       char *cmdline;
+       unsigned long mod_cnt;
+       struct mod_info *mods;
+};
+
+struct mod_info
+{
+       void *mod_start;
+       void *mod_end;
+       char *mod_string;
+       void *reserved;
+};
+
+struct info_section
+{
+       unsigned int signature;
+       void (*firstrun)();
+};
+
+void panic(const char *msg)
+{
+       puts("PANIC: ");
+       puts(msg);
+       puts("\nSystem halted\n");
+       while(1) asm("hlt");
+}
+
+void c_start(unsigned int magic, struct mb_info *mbinfo)
+{
+       struct mod_info *mods = mbinfo->mods;
+       unsigned short *grubptr = (unsigned short *)0x7CFE;
+       unsigned char smramc;
+       int i;
+       
+       void (*realmode)() = (void (*)()) 0x4000;
+       
+       show_cursor();
+       puts("NetWatch loader\n");
+       
+       if (magic != 0x2BADB002)
+               panic("Bootloader was not multiboot compliant; cannot continue.");
+       
+       for (i = 0; i < mbinfo->mod_cnt; i++)
+       {
+               puts("Module found:\n");
+               puts("  Start: "); puthex(mods[i].mod_start); puts("\n");
+               puts("  Size: "); puthex(mods[i].mod_end - mods[i].mod_start); puts("\n");
+               puts("  Name: "); puts(mods[i].mod_string); puts("\n");
+       }
+
+       if (mbinfo->mod_cnt != 1)
+               panic("Expected exactly one module; cannot continue.");
+
+       puts("Current USB state is: "); puthex(pci_read16(0, 31, 2, 0xC0)); puts(" "); puthex(pci_read16(0, 31, 4, 0xC0)); puts("\n");
+       puts("Current SMI state is: "); puthex(inl(0x830)); puts("\n");
+       puts("Current SMRAMC state is: "); puthex(pci_read8(0, 0, 0, 0x70)); puts("\n");
+       
+       outl(0x830, inl(0x830) & ~0x1); /* turn off SMIs */
+       
+       /* Try really hard to shut up USB_LEGKEY. */
+       pci_write16(0, 31, 2, 0xC0, pci_read16(0, 31, 2, 0xC0));
+       pci_write16(0, 31, 2, 0xC0, 0);
+       pci_write16(0, 31, 4, 0xC0, pci_read16(0, 31, 4, 0xC0));
+       pci_write16(0, 31, 4, 0xC0, 0);
+
+
+       /* Open the SMRAM aperture and load our ELF. */
+       smram_state_t old_smramc = smram_save_state();
+
+       if (smram_aseg_set_state(SMRAM_ASEG_OPEN) != 0)
+               panic("Opening SMRAM failed; cannot load ELF.");
+
+       load_elf(mods[0].mod_start, mods[0].mod_end - mods[0].mod_start);
+
+       struct info_section * info = (struct info_section *)0x10000;
+       if (info->signature != INFO_SIGNATURE)
+       {
+               smram_restore_state(old_smramc);                /* Restore so that video ram is touchable again. */
+               panic("Info section signature mismatch.");
+       }
+
+       info->firstrun();
+       smram_restore_state(old_smramc);
+
+       puts("Waiting for a bit before returning to real mode...");
+       for (i=0; i<0x500000; i++)
+       {
+               if ((i % 0x100000) == 0)
+                       puts(".");
+               inb(0x80);
+       }
+       puts("\n");
+
+       puts("Now returning to real mode.\n");  
+       memcpy(0x4000, _binary_realmode_bin_start, (int)&_binary_realmode_bin_size);
+       realmode();     // goodbye!
 }