Implement Mutexes and supporting syscalls, cleanup/optimize scheduler

kernel/amd64/mm.c

@@ -240,15 +240,11 @@ uintptr_t mm_alloc_user_pd_phys (void) {
 
 /* Reload after map/unmap operation was performed. This function does the TLB shootdown. */
 void mm_reload (void) {
-  spin_lock (&mm_lock);
-
   struct limine_mp_response* mp = limine_mp_request.response;
 
   for (size_t i = 0; i < mp->cpu_count; i++) {
     amd64_lapic_ipi (mp->cpus[i]->lapic_id, TLB_SHOOTDOWN);
   }
-
-  spin_unlock (&mm_lock);
 }
 
 bool mm_validate (struct pd* pd, uintptr_t vaddr, uint32_t flags) {