[PATCH] fix 4k irqstacks on x86 (and add voyager support)

There's a bug in the x86 code in that it sets the boot CPU to zero.

This isn't correct since some subarch's use physically indexed CPUs. 
However, subarchs have either set the boot cpu before irq_INIT() (or
just inherited the default zero from INIT_THREAD_INFO()), so it's safe
to believe current_thread_info()->cpu about the boot cpu.

arch/i386/kernel/i8259.c

@@ -445,6 +445,5 @@ void __init init_IRQ(void)
 	if (boot_cpu_data.hard_math && !cpu_has_fpu)
 		setup_irq(FPU_IRQ, &fpu_irq);
 
-	current_thread_info()->cpu = 0;
-	irq_ctx_init(0);
+	irq_ctx_init(current_thread_info()->cpu);
 }

arch/i386/mach-voyager/voyager_smp.c

@@ -599,12 +599,10 @@ do_boot_cpu(__u8 cpu)
 	idle->thread.eip = (unsigned long) start_secondary;
 	unhash_process(idle);
 	/* init_tasks (in sched.c) is indexed logically */
-#if 0
-	// for AC kernels
-	stack_start.esp = (THREAD_SIZE + (__u8 *)TSK_TO_KSTACK(idle));
-#else
-	stack_start.esp = (void *) (1024 + PAGE_SIZE + (char *)idle->thread_info);
-#endif
+	stack_start.esp = (void *) idle->thread.esp;
+
+	irq_ctx_init(cpu);
+
 	/* Note: Don't modify initial ss override */
 	VDEBUG(("VOYAGER SMP: Booting CPU%d at 0x%lx[%x:%x], stack %p\n", cpu, 
 		(unsigned long)hijack_source.val, hijack_source.idt.Segment,

arch/i386/mach-voyager/voyager_thread.c

@@ -135,7 +135,7 @@ thread(void *unused)
 	init_timer(&wakeup_timer);
 
 	sigfillset(&current->blocked);
-	current->tty = NULL;	/* get rid of controlling tty */
+	current->signal->tty = NULL;
 
 	printk(KERN_NOTICE "Voyager starting monitor thread\n");