diff --git a/sys/amd64/machine.c b/sys/amd64/machine.c index 2f538bf..c3aeb07 100644 --- a/sys/amd64/machine.c +++ b/sys/amd64/machine.c @@ -40,7 +40,16 @@ static PseudoDescriptor GDTDescriptor[MAX_CPUS]; TaskStateSegment64 TSS[MAX_CPUS]; static char df_stack[4096]; - + +/* + * Machine_GDTInit -- + * + * Configures the Global Descriptor Table (GDT) that lists all segments + * and privilege levels in x86. 64-bit mode uses flat 64-bit segments and + * doesn't support offsets and limits except for the special FS/GS segment + * registers. We create four segments for the kernel code/data and user + * code/data. + */ static void Machine_GDTInit() { @@ -76,6 +85,12 @@ Machine_GDTInit() kprintf("Done!\n"); } +/* + * Machine_TSSInit -- + * + * Configures the Task State Segment (TSS) that specifies the kernel stack + * pointer during an interrupt. + */ static void Machine_TSSInit() { @@ -104,6 +119,13 @@ Machine_TSSInit() kprintf("Done!\n"); } +/* + * Machine_SyscallInit -- + * + * Configure the model specific registers (MSRs) that specify how to + * transfer control to the operating system when the system call + * instruction is invoked. + */ static void Machine_SyscallInit() { @@ -117,6 +139,11 @@ Machine_SyscallInit() kprintf("Done!\n"); } +/* + * Machine_EarlyInit -- + * + * Initializes early kernel state. + */ void Machine_EarlyInit() { @@ -133,23 +160,42 @@ Machine_IdleThread(void *test) while (1) { enable_interrupts(); hlt(); } } +/* + * Machine_Init -- + * + * At this point the assembly startup code has setup temporary processor + * data structures sufficient to execute C code and make it through this + * initialization routine. + */ void Machine_Init() { + /* + * Initialize Processor State + */ Machine_GDTInit(); Machine_TSSInit(); Trap_Init(); Machine_SyscallInit(); clts(); // Enable FPU/XMM + /* + * Initialize Memory Allocation and Virtual Memory + */ PAlloc_AddRegion(DMPA2VA(16*1024*1024), 16*1024*1024); PMap_Init(); XMem_Init(); PAlloc_LateInit(); MachineBoot_AddMem(); + /* + * Initialize Time Keeping + */ KTime_Init(); RTC_Init(); // Finishes initializing KTime + /* + * Initialize Interrupts + */ IRQ_Init(); LAPIC_Init(); IOAPIC_Init(); @@ -158,13 +204,22 @@ void Machine_Init() KTimer_Init(); // Depends on RTC and KTime + /* + * Initialize Additional Processors + */ MP_Init(); - PS2_Init(); - PCI_Init(); - IDE_Init(); + /* + * Initialize Basic Devices + */ + PS2_Init(); // PS2 Keyboard + PCI_Init(); // PCI BUS + IDE_Init(); // IDE Disk Controller BufCache_Init(); + /* + * Open the primary disk and mount the root file system + */ Disk *root = Disk_GetByID(0, 0); if (!root) Panic("No boot disk!"); @@ -172,17 +227,28 @@ void Machine_Init() Critical_Exit(); + /* + * Create the idle thread + */ Thread *thr = Thread_KThreadCreate(&Machine_IdleThread, NULL); if (thr == NULL) { kprintf("Couldn't create idle thread!\n"); } Sched_SetRunnable(thr); + /* + * Load the init processor + */ Loader_LoadInit(); breakpoint(); } +/* + * Machine_InitAP -- + * + * Shorter initialization routine for co-processors. + */ void Machine_InitAP() { Critical_Enter();