Load into SMRAM, not just video RAM.

[netwatch.git] / grubload / multiboot_c.c

diff --git a/grubload/multiboot_c.c b/grubload/multiboot_c.c
index c87b6755634dfab2c8b7b10c669f83ff33f6397d..ad421b4b713f6aa24a46c30e7a32c07b8e5a7c4f 100644 (file)
--- a/grubload/multiboot_c.c
+++ b/grubload/multiboot_c.c
@@ -1,4 +1,8 @@
 #include "console.h"
+#include <io.h>
+
+extern char _binary_realmode_bin_start[];
+extern int _binary_realmode_bin_size;
 
 struct mb_info
 {
@@ -21,8 +25,11 @@ struct mod_info
 void c_start(unsigned int magic, struct mb_info *wee)
 {
        unsigned short *grubptr = 0x7CFE;
+       unsigned char smramc;
        int i;
        
+       void (*realmode)() = 0x4000;
+       
        puts("Magic is: ");
        puthex(magic);
        puts("\nMultiboot header is: ");
@@ -33,7 +40,8 @@ void c_start(unsigned int magic, struct mb_info *wee)
        puts("Grubptr is: ");
        puthex(*grubptr);
        puts("\n");
-       
+
+
        for (i = 0; i < wee->mod_cnt; i++)
        {
                puts("Module:\n");
@@ -41,6 +49,40 @@ void c_start(unsigned int magic, struct mb_info *wee)
                puts("  Size: "); puthex(wee->mods[i].mod_end - wee->mods[i].mod_start); puts("\n");
                puts("  Name: "); puts(wee->mods[i].mod_string); puts("\n");
        }
-       while (1)
-               ;
+
+       if (wee->mod_cnt != 1)
+       {
+               puts("Expected exactly one module; cannot continue.\n");
+               while(1) asm("hlt");
+       }
+
+       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) & ~0x2001);      /* 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);
+       smramc = pci_read8(0, 0, 0, 0x70);
+       pci_write8(0, 0, 0, 0x70, (smramc & 0xF0) | 0x04);
+       load_elf(wee->mods[0].mod_start, wee->mods[0].mod_end - wee->mods[0].mod_start);
+       pci_write8(0, 0, 0, 0x70, smramc);
+       outb(0x830, inb(0x830) | 0x41); /* turn on the SMIs we want */
+       
+       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!
 }