SMP - The slave CPUs turn paging on

- APs wait until BSP turns paging on, it is not possible to safely
  execute any code on APs until we can turn paging on as well as it
  must be done synchronously everywhere

- APs turn paging on but do not continue and wait

kernel/arch/i386/apic.c

@@ -835,7 +835,7 @@ PUBLIC void apic_idt_init(const int reset)
 	}
 
 #ifdef CONFIG_APIC_DEBUG
-	if (cpu_is_bsp(cpuid))
+	if (is_bsp)
 		printf("APIC debugging is enabled\n");
 	lapic_set_dummy_handlers();
 #endif

kernel/arch/i386/arch_smp.c

@@ -190,6 +190,12 @@ PRIVATE void ap_finish_booting(void)
 	while(!i386_paging_enabled)
 		arch_pause();
 
+	/*
+	 * we must load some page tables befre we turn paging on. As VM is
+	 * always present we use those
+	 */
+	segmentation2paging(proc_addr(VM_PROC_NR));
+
 	BKL_LOCK();
 	printf("CPU %d is running\n", cpu);
 	BKL_UNLOCK();

kernel/arch/i386/include/arch_proto.h

@@ -54,6 +54,7 @@ _PROTOTYPE( void kernel_call_entry, (void) );
 _PROTOTYPE( void level0_call, (void) );
 
 /* memory.c */
+_PROTOTYPE( void segmentation2paging, (struct proc * current));
 _PROTOTYPE( void i386_freepde, (int pde));
 _PROTOTYPE( void getcr3val, (void));
 

kernel/main.c

@@ -285,8 +285,14 @@ PUBLIC int main(void)
   } else if (config_no_smp) {
 	  BOOT_VERBOSE(printf("SMP disabled, using legacy PIC\n"));
 	  smp_single_cpu_fallback();
-  } else
+  } else {
 	  smp_init();
+	  /*
+	   * if smp_init() returns it means that it failed and we try to finish
+	   * single CPU booting
+	   */
+	  bsp_finish_booting();
+  }
 #else
   /* 
    * if configured for a single CPU, we are already on the kernel stack which we