kernel: Ignore all non-bootstrap processors

kernel/src/arch/CPU.h

@@ -26,6 +26,8 @@ namespace CPU
     void get_stack_trace_at(Registers* regs, void (*callback)(u64, void*), void* arg);
     void print_stack_trace_at(Registers* regs);
 
+    u16 get_processor_id();
+
     [[noreturn]] void bootstrap_switch_stack(u64 stack, void* function);
 
     void pause();

kernel/src/arch/x86_64/CPU.cpp

@@ -335,6 +335,14 @@ namespace CPU
     {
         asm volatile("pause");
     }
+
+    u16 get_processor_id()
+    {
+        unsigned int unused;
+        unsigned int ebx = 0;
+        __get_cpuid(1, &unused, &ebx, &unused, &unused);
+        return (u16)(ebx >> 24);
+    }
 }
 
 // called by kernel_yield

kernel/src/boot/Init.cpp

@@ -17,6 +17,9 @@ void Init::check_magic()
         kerrorln("ERROR: Invalid magic value from bootloader");
         CPU::efficient_halt();
     }
+
+    // Stop all secondary processors for now
+    if (CPU::get_processor_id() != bootboot.bspid) { CPU::efficient_halt(); }
 }
 
 void Init::early_init()