metal-cos/sys/amd64/machine.c

#include <stdbool.h>
#include <stdint.h>

#include <kconfig.h>
#include <kassert.h>
#include <kmem.h>

#include "amd64.h"
#include "ioapic.h"
#include "lapic.h"
#include "trap.h"
#include "pmap.h"

extern void PCI_Init();
extern void IDE_Init();

#define GDT_MAX 7

static SegmentDescriptor GDT[MAX_CPUS][GDT_MAX];
static PseudoDescriptor GDTDescriptor[MAX_CPUS];
static TaskStateSegment64 TSS[MAX_CPUS];

static char df_stack[4096];

void Machine_GDTInit()
{
    uint64_t offset;
    uint64_t tmp;

    kprintf("Initializing GDT... "); // Caused pagefault??

    GDT[0][0] = 0x0;
    GDT[0][1] = 0x00AF9A000000FFFFULL; /* Kernel CS */
    GDT[0][2] = 0x00CF92000000FFFFULL; /* Kernel DS */
    GDT[5][1] = 0x00AFFA000000FFFFULL; /* User CS */
    GDT[6][2] = 0x00CFF2000000FFFFULL; /* User DS */

    // TSS
    GDT[0][3] = 0x0; /* TSS */
    GDT[0][4] = sizeof(TaskStateSegment64);
    offset = (uint64_t)&TSS[0];
    tmp = offset & 0x00FFFFFF;
    GDT[0][4] |= (tmp << 16);
    tmp = offset & 0xFF000000;
    GDT[0][4] |= (tmp << 56);
    GDT[0][4] |= 0x89ULL << 40;

    GDTDescriptor[0].off = (uint64_t)&GDT[0];
    GDTDescriptor[0].lim = 8*GDT_MAX - 1;

    lgdt(&GDTDescriptor[0]);

    kprintf("Done!\n");
}

void Machine_TSSInit()
{
    kprintf("Initializing TSS... ");

    TSS[0]._unused0 = 0;
    TSS[0]._unused1 = 0;
    TSS[0]._unused2 = 0;
    TSS[0]._unused3 = 0;
    TSS[0]._unused4 = 0;
    TSS[0].ist1 = (uint64_t)&df_stack;
    TSS[0].rsp0 = 0;
    TSS[0].rsp1 = 0;
    TSS[0].rsp2 = 0;

    ltr(SEL_TSS);

    kprintf("Done!\n");
}

void Machine_SyscallInit()
{
    kprintf("Initializing Syscall... ");

    wrmsr(MSR_STAR, SEL_KCS << 32 | SEL_UCS << 48);
    wrmsr(MSR_LSTAR, 0);
    wrmsr(MSR_CSTAR, 0);
    wrmsr(MSR_SFMASK, 0);

    kprintf("Done!\n");
}

void Machine_Init()
{
    Machine_GDTInit();
    Machine_TSSInit();
    Trap_Init();
    //Machine_SyscallInit();

    PAlloc_AddRegion(16*1024*1024, 16*1024*1024);
    PMap_Init();

    IRQ_Init();
    LAPIC_Init();
    IOAPIC_Init();

    PCI_Init();
    IDE_Init();
}