X-Git-Url: http://git.joshuawise.com/netwatch.git/blobdiff_plain/c34aba053b84fc15e91e96e04291d911bcd2adb0..6b988ea9bdbc4f1e78bbde0652036c083dbc4aa1:/grubload/multiboot_c.c

diff --git a/grubload/multiboot_c.c b/grubload/multiboot_c.c
index c75e830..890a003 100644
--- a/grubload/multiboot_c.c
+++ b/grubload/multiboot_c.c
@@ -2,6 +2,8 @@
 #include <io.h>
 #include <smram.h>
 
+#define INFO_SIGNATURE 0x5754454E
+
 extern char _binary_realmode_bin_start[];
 extern int _binary_realmode_bin_size;
 
@@ -23,9 +25,23 @@ struct mod_info
 	void *reserved;
 };
 
-void c_start(unsigned int magic, struct mb_info *info)
+struct info_section
 {
-	struct mod_info *mods = mods;
+	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;
@@ -36,12 +52,9 @@ void c_start(unsigned int magic, struct mb_info *info)
 	puts("NetWatch loader\n");
 	
 	if (magic != 0x2BADB002)
-	{
-		puts("Bootloader was not multiboot compliant; cannot continue.\n");
-		while(1) asm("hlt");
-	}
+		panic("Bootloader was not multiboot compliant; cannot continue.");
 	
-	for (i = 0; i < info->mod_cnt; i++)
+	for (i = 0; i < mbinfo->mod_cnt; i++)
 	{
 		puts("Module found:\n");
 		puts("  Start: "); puthex(mods[i].mod_start); puts("\n");
@@ -49,11 +62,8 @@ void c_start(unsigned int magic, struct mb_info *info)
 		puts("  Name: "); puts(mods[i].mod_string); puts("\n");
 	}
 
-	if (info->mod_cnt != 1)
-	{
-		puts("Expected exactly one module; cannot continue.\n");
-		while(1) asm("hlt");
-	}
+	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");
@@ -72,17 +82,20 @@ void c_start(unsigned int magic, struct mb_info *info)
 	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)
 	{
-		puts("Opening SMRAM failed; cannot load ELF.\n");
-	}
-	else
-	{
-		load_elf(mods[0].mod_start, mods[0].mod_end - mods[0].mod_start);
-		smram_restore_state(old_smramc);
+		smram_restore_state(old_smramc);		/* Restore so that video ram is touchable again. */
+		panic("Info section signature mismatch.");
 	}
 
-	outb(0x830, inb(0x830) | 0x41);	/* turn on the SMIs we want */
-	
+	info->firstrun();
+	smram_restore_state(old_smramc);
+
 	puts("Waiting for a bit before returning to real mode...");
 	for (i=0; i<0x500000; i++)
 	{