fixes from SONE

src/arch/i386/lib/idt.c

@@ -132,6 +132,9 @@ pcibios(
         unsigned long *pflags
         );
 #endif
+
+extern void vga_exit(void);
+
 int
 biosint(
 	unsigned long intnumber,
@@ -143,19 +146,16 @@ biosint(
 	unsigned long edx, 
 	unsigned long ecx, 
 	unsigned long eax, 
-	// these came in from 16-bit land
+	unsigned long cs_ip,
-	// but gcc does something weird we have to undo.
+	unsigned short stackflags
-	unsigned short stackip,
-	unsigned short stackflags,
-	unsigned short stackcs
 	) {
 	unsigned long ip; 
 	unsigned long cs; 
 	unsigned long flags;
 	int ret = -1;
 
-	ip = stackip;
+	ip = cs_ip & 0xffff;
-	cs = stackcs;
+	cs = cs_ip >> 16;
 	flags = stackflags;
 
 	printk_debug("biosint: # 0x%lx, eax 0x%lx ebx 0x%lx ecx 0x%lx edx 0x%lx\n", 
@@ -164,6 +164,21 @@ biosint(
 	printk_debug("biosint: ip 0x%x cs 0x%x flags 0x%x\n", ip, cs, flags);
 	// cases in a good compiler are just as good as your own tables. 
 	switch (intnumber) {
+	case 0 ... 15:
+		// These are not BIOS service, but the CPU-generated exceptions
+		printk_info("biosint: Oops, exception %u\n", intnumber);
+		if (esp < 0x1000) {
+		    printk_debug("Stack contents: ");
+		    while (esp < 0x1000) {
+			printk_debug("0x%04x ", *(unsigned short *) esp);
+			esp += 2;
+		    }
+		    printk_debug("\n");
+		}
+		printk_debug("biosint: Bailing out\n");
+		// "longjmp"
+		vga_exit();
+		break;
 #ifdef CONFIG_PCIBIOS
 	case PCIBIOS:
 		ret = pcibios( &edi, &esi, &ebp, &esp, 
@@ -208,11 +223,21 @@ setup_realmode_idt(void) {
 	// and get it that way. But that's really disgusting.
 	for (i = 0; i < 256; i++) {
 		idts[i].cs = 0;
-		codeptr = 1024 + i * codesize;
+		codeptr = (char*) 4096 + i * codesize;
-		idts[i].offset = codeptr;
+		idts[i].offset = (unsigned) codeptr;
-		memcpy((void *) codeptr, &idthandle, codesize);
+		memcpy(codeptr, &idthandle, codesize);
 		intbyte = codeptr + 3;
 		*intbyte = i;
 	}
 
+	// fixed entry points
+
+	// VGA BIOSes tend to hardcode f000:f065 as the previous handler of
+	// int10. 
+	// calling convention here is the same as INTs, we can reuse
+	// the int entry code.
+	codeptr = (char*) 0xff065;
+	memcpy(codeptr, &idthandle, codesize);
+	intbyte = codeptr + 3;
+	*intbyte = 0x42; /* int42 is the relocated int10 */
 }

src/arch/i386/lib/vgabios.c

@@ -69,15 +69,21 @@ static char rcsid[] = "$Id$";
 
 
 /* The address arguments to this function are PHYSICAL ADDRESSES */ 
-static void real_mode_switch_call_vga(void)
+static void real_mode_switch_call_vga(unsigned long devfn)
 {
   __asm__ __volatile__
       (
+       // paranoia -- does ecx get saved? not sure. This is 
+       // the easiest safe thing to do.
+       "pushal\n"
 	/* save the stack */
 	"mov %esp, __stack\n"
 	"jmp 1f\n"
 	"__stack: .long 0\n"
 	"1:\n"
+	/* get devfn into %ecx */
+	"movl    %esp, %ebp\n"
+	"movl    8(%ebp), %ecx\n"
 	/*  This configures CS properly for real mode. */
        "    ljmp $0x28, $__rms_16bit\n"
        "__rms_16bit:                 \n"
@@ -110,7 +116,7 @@ static void real_mode_switch_call_vga(void)
        "    mov  %ax, %ss          \n"
        "    movl  $0x1000, %eax       \n"
        "    movl  %eax, %esp          \n"
- 	/* ebugging for RGM */
+ 	/* debugging for RGM */
        "    mov $0x11, %al	\n"
 	" outb	%al, $0x80\n"
 
@@ -120,6 +126,7 @@ static void real_mode_switch_call_vga(void)
        "    mov  %ax, %es          \n"
        "    mov  %ax, %fs          \n"
        "    mov  %ax, %gs          \n"
+       "    mov %cx, %ax	\n"
 	" .byte 0x9a, 0x03, 0, 0, 0xc0  \n"
 	" movb $0x55, %al\noutb %al, $0x80\n"
        /* if we got here, just about done. 
@@ -139,7 +146,10 @@ static void real_mode_switch_call_vga(void)
        "    mov  %ax, %fs          \n"
        "    mov  %ax, %gs          \n"
        "    mov  %ax, %ss          \n"
+	".globl vga_exit\n"
+	"vga_exit:\n"
        "    mov  __stack, %esp\n"
+       "    popal\n"
        );
 }
 __asm__ (".text\n""real_mode_switch_end:\n");
@@ -149,11 +159,21 @@ void
 do_vgabios(void)
 {
   struct pci_dev *dev;
+  unsigned long busdevfn;
   unsigned int rom = 0;
   unsigned char *buf;
   unsigned int size = 64*1024;
   int i;
 
+for (i=0x400; i<0x500; i++) {
+  printk_debug("%02x%c", *(unsigned char *)i, i%16==15 ? '\n' : ' ');
+  *(unsigned char *) i = 0;
+}
+
+for (i=0x400; i<0x500; i++) {
+  printk_debug("%02x%c", *(unsigned char *)i, i%16==15 ? '\n' : ' ');
+}
+
   dev = pci_find_class(PCI_CLASS_DISPLAY_VGA <<8, NULL);
 
   if (! dev) {
@@ -179,7 +199,8 @@ do_vgabios(void)
   	for(i = 0; i < 16; i++)
     		printk_debug("0x%x ", buf[i]);
   	// check signature here later!
-  	real_mode_switch_call_vga();
+	busdevfn = (dev->bus->secondary << 8) | dev->devfn;
+  	real_mode_switch_call_vga(busdevfn);
   } else 
 	printk_debug("BAD SIGNATURE 0x%x 0x%x\n", buf[0], buf[1]);
 #ifndef VGABIOS_START