[kernel] Clean up main.cpp and others

The kernel/main.cpp and kernel/memory_bootstrap.cpp files had become
something of a junk drawer. This change cleans them up in the following
ways:

- Most CPU initialization has moved to cpu.cpp, allowing several
  functions to be made static and removed from cpu.h
- Multi-core startup code has moved to the new smp.h and smp.cpp, and
  ap_startup.s has been renamed smp.s to match.
- run_constructors() has moved to memory_bootstrap.cpp, and all the
  functionality of that file has been hidden behind a new public
  interface mem::initialize().
- load_init_server() has moved from memory_bootstrap.cpp to main.cpp

src/kernel/cpu.cpp

@@ -1,3 +1,4 @@
+#include <new>
 #include <stdint.h>
 #include <string.h>
 
@@ -10,7 +11,6 @@
 #include "logger.h"
 #include "msr.h"
 #include "objects/thread.h"
-#include "objects/vm_area.h"
 #include "scheduler.h"
 #include "syscall.h"
 #include "tss.h"
@@ -22,6 +22,9 @@ panic_data *g_panic_data_p = &g_panic_data;
 
 cpu_data g_bsp_cpu_data;
 
+
+// Validate the required CPU features are present. Really, the bootloader already
+// validated the required features, but still iterate the options and log about them.
 void
 cpu_validate()
 {
@@ -45,18 +48,12 @@ cpu_validate()
 #undef CPU_FEATURE_REQ
 }
 
-void
-global_cpu_init()
-{
-    memset(&g_panic_data, 0, sizeof(g_panic_data));
-}
 
-void
+// Do early (before cpu_init) initialization work. Only needs to be called manually for
+// the BSP, otherwise cpu_init will call it.
+static void
 cpu_early_init(cpu_data *cpu)
 {
-    if (cpu->index == 0)
-        global_cpu_init();
-
     cpu->idt->install();
     cpu->gdt->install();
 
@@ -64,6 +61,70 @@ cpu_early_init(cpu_data *cpu)
     wrmsr(msr::ia32_gs_base, reinterpret_cast<uintptr_t>(cpu));
 }
 
+cpu_data *
+bsp_early_init()
+{
+    cpu_validate();
+    memset(&g_panic_data, 0, sizeof(g_panic_data));
+
+    extern IDT &g_bsp_idt;
+    extern TSS &g_bsp_tss;
+    extern GDT &g_bsp_gdt;
+    extern uintptr_t idle_stack_end;
+
+    cpu_data *cpu = &g_bsp_cpu_data;
+    memset(cpu, 0, sizeof(cpu_data));
+
+    cpu->self = cpu;
+    cpu->idt = new (&g_bsp_idt) IDT;
+    cpu->tss = new (&g_bsp_tss) TSS;
+    cpu->gdt = new (&g_bsp_gdt) GDT {cpu->tss};
+    cpu->rsp0 = idle_stack_end;
+    cpu_early_init(cpu);
+
+    return cpu;
+}
+
+void
+bsp_late_init()
+{
+    // BSP didn't set up IST stacks yet
+    extern TSS &g_bsp_tss;
+    uint8_t ist_entries = IDT::used_ist_entries();
+    g_bsp_tss.create_ist_stacks(ist_entries);
+
+    uint64_t cr0, cr4;
+    asm ("mov %%cr0, %0" : "=r"(cr0));
+    asm ("mov %%cr4, %0" : "=r"(cr4));
+    uint64_t efer = rdmsr(msr::ia32_efer);
+    log::debug(logs::boot, "Control regs: cr0:%lx cr4:%lx efer:%lx", cr0, cr4, efer);
+
+    syscall_initialize();
+}
+
+cpu_data *
+cpu_create(uint16_t id, uint16_t index)
+{
+    // Set up the CPU data structures
+    IDT *idt = new IDT;
+    TSS *tss = new TSS;
+    GDT *gdt = new GDT {tss};
+    cpu_data *cpu = new cpu_data;
+    memset(cpu, 0, sizeof(cpu_data));
+
+    cpu->self = cpu;
+    cpu->id = id;
+    cpu->index = index;
+    cpu->idt = idt;
+    cpu->tss = tss;
+    cpu->gdt = gdt;
+
+    uint8_t ist_entries = IDT::used_ist_entries();
+    tss->create_ist_stacks(ist_entries);
+
+    return cpu;
+}
+
 void
 cpu_init(cpu_data *cpu, bool bsp)
 {
@@ -93,4 +154,17 @@ cpu_init(cpu_data *cpu, bool bsp)
     wrmsr(msr::ia32_pat, pat);
 
     cpu->idt->add_ist_entries();
+
+    uintptr_t apic_base =
+        device_manager::get().get_lapic_base();
+
+    lapic *apic = new lapic(apic_base);
+    cpu->apic = apic;
+    apic->enable();
+
+    if (bsp) {
+        // BSP never got an id, set that up now
+        cpu->id = apic->get_id();
+        apic->calibrate_timer();
+    }
 }