os-k/kaleid/kernel/ke/idt.c

//----------------------------------------------------------------------------//
//                                OS on Kaleid                                //
//                                                                            //
//  Desc:  Interrupt related functions                                        //
//                                                                            //
//                                                                            //
//  Copyright © 2018-2021 The OS/K Team                                       //
//                                                                            //
//  This file is part of OS/K.                                                //
//                                                                            //
//  OS/K is free software: you can redistribute it and/or modify              //
//  it under the terms of the GNU General Public License as published by      //
//  the Free Software Foundation, either version 3 of the License, or         //
//  any later version.                                                        //
//                                                                            //
//  OS/K is distributed in the hope that it will be useful,                   //
//  but WITHOUT ANY WARRANTY//without even the implied warranty of            //
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the             //
//  GNU General Public License for more details.                              //
//                                                                            //
//  You should have received a copy of the GNU General Public License         //
//  along with OS/K.  If not, see <https://www.gnu.org/licenses/>.            //
//----------------------------------------------------------------------------//

#include <libbuf.h>
#include <init/boot.h>
#include <ke/idt.h>
#include <io/vga.h>
#include <io/spkr.h>
#include <ke/time.h>

IdtEntry_t idt[256] = { 0 };
IdtPtr_t _KeIdtPtr;
bool KeIdtIsInitialized = 0;
ulong KeSpuriousCount = 0;

static ISRList_t isrList = { 0 };

static char *ExceptionsChar[32] = {
    "Divide Error Fault",
    "Debug Exception Trap",
    "Non-maskable Interrupt",
    "Breakpoint Trap",
    "Overflow Trap",
    "Bound Range Exceeded Fault",
    "Invalid Opcode Fault",
    "Device Not Available or No Math Coprocessor Fault",
    "Double Fault Abort",
    "Coprocessor Segment Overrun Fault (Legacy)",
    "Invalid TSS Fault",
    "Segment Not Present Fault",
    "Stack Segment fault",
    "General Protection Fault",
    "Page Fault",
    "Intel Reserved",
    "x87 FPU Floating Point or Math Fault",
    "Alignment Check Fault",
    "Machine Check Abort",
    "SIMD Floating Point Fault",
    "Virtualization Exception Fault",
    "Intel Reserved",
    "Intel Reserved",
    "Intel Reserved",
    "Intel Reserved",
    "Intel Reserved",
    "Intel Reserved",
    "Intel Reserved",
    "Intel Reserved",
    "Intel Reserved",
    "Security Exception",
    "Intel Reserved"
};

static void EnablePIC(void);
static void EarlyExceptionHandler(ISRFrame_t *regs);
static void DoubleFaultHandler(ISRFrame_t *regs);
static void EarlySyscallHandler(ISRFrame_t *regs);

//
// Registers an isr with his IRQ to handle driver interrupts
//
error_t KeRegisterISR(void (*isr)(ISRFrame_t *regs), uchar isrNo)
{
    uchar n = isrList.n; // Number of registered entries
    int OverWriting = 0;

    assert(KeIdtIsInitialized); // IDT initialized

    if (n == 0) goto settingUp;

    for (int i = 0; i < n; i++) {
        if (isrNo == isrList.entry[i].isrNo) { // If that isr is already 
                                               // registered, overwrite using 
                                               // the same entry
            n = i;
            OverWriting++;
            break;
        }
    }

    if ((n == 255))             // That IRQ cannot exists
        return ENOMEM;

settingUp:
    isrList.entry[n].isr = isr;
    isrList.entry[n].isrNo = isrNo;
    if (!OverWriting) isrList.n++;

    DebugLog("Interrupt %d registered to function %p\n", isrNo, isr);
    return EOK;
}

//
// Installs the IDT in order to activate the interrupts handling
//
void KeSetupIDT(void)
{
    // XXX detect the APIC with cpuid and, perhaps, use it !
    EnablePIC();

    ushort codeSeg = (ushort)(ulong)BtLoaderInfo.codeSegment;

    // Set IDT ptr
    _KeIdtPtr.limit = (sizeof(IdtEntry_t) * 256) - 1;
    _KeIdtPtr.base = &idt;

    // Set IDT Exception Gates
    KeSetIDTGate(0x00, (ulong)isr0, codeSeg, 0x8E, 2);
    KeSetIDTGate(0x01, (ulong)isr1, codeSeg, 0x8E, 2);
    KeSetIDTGate(0x02, (ulong)isr2, codeSeg, 0x8E, 2);
    KeSetIDTGate(0x03, (ulong)isr3, codeSeg, 0x8E, 2);
    KeSetIDTGate(0x04, (ulong)isr4, codeSeg, 0x8E, 2);
    KeSetIDTGate(0x05, (ulong)isr5, codeSeg, 0x8E, 2);
    KeSetIDTGate(0x06, (ulong)isr6, codeSeg, 0x8E, 2);
    KeSetIDTGate(0x07, (ulong)isr7, codeSeg, 0x8E, 2);   // XXX device not available, useful for FPU save/restore when multitasking
    KeSetIDTGate(0x08, (ulong)isr8, codeSeg, 0x8E, 1);   // DOUBLE FAULT
    KeSetIDTGate(0x09, (ulong)isr9, codeSeg, 0x8E, 2);
    KeSetIDTGate(0x0A, (ulong)isr10, codeSeg, 0x8E, 0);  // INVALID TSS, 0 means don't use Interrupt Stack Table
    KeSetIDTGate(0x0B, (ulong)isr11, codeSeg, 0x8E, 2);
    KeSetIDTGate(0x0C, (ulong)isr12, codeSeg, 0x8E, 1);  // STACK SEGMENT FAULT
    KeSetIDTGate(0x0D, (ulong)isr13, codeSeg, 0x8E, 2);  // GPF
    KeSetIDTGate(0x0E, (ulong)isr14, codeSeg, 0x8E, 2);
    KeSetIDTGate(0x0F, (ulong)isr15, codeSeg, 0x8E, 2);  // INTEL RESERVED
    KeSetIDTGate(0x10, (ulong)isr16, codeSeg, 0x8E, 2);
    KeSetIDTGate(0x11, (ulong)isr17, codeSeg, 0x8E, 2);
    KeSetIDTGate(0x12, (ulong)isr18, codeSeg, 0x8E, 2);
    KeSetIDTGate(0x13, (ulong)isr19, codeSeg, 0x8E, 2);
    KeSetIDTGate(0x14, (ulong)isr20, codeSeg, 0x8E, 2);
    KeSetIDTGate(0x15, (ulong)isr21, codeSeg, 0x8E, 2);  // INTEL RESERVED
    KeSetIDTGate(0x16, (ulong)isr22, codeSeg, 0x8E, 2);  // INTEL RESERVED
    KeSetIDTGate(0x17, (ulong)isr23, codeSeg, 0x8E, 2);  // INTEL RESERVED
    KeSetIDTGate(0x18, (ulong)isr24, codeSeg, 0x8E, 2);  // INTEL RESERVED
    KeSetIDTGate(0x19, (ulong)isr25, codeSeg, 0x8E, 2);  // INTEL RESERVED
    KeSetIDTGate(0x1A, (ulong)isr26, codeSeg, 0x8E, 2);  // INTEL RESERVED
    KeSetIDTGate(0x1B, (ulong)isr27, codeSeg, 0x8E, 2);  // INTEL RESERVED
    KeSetIDTGate(0x1C, (ulong)isr28, codeSeg, 0x8E, 2);  // INTEL RESERVED
    KeSetIDTGate(0x1D, (ulong)isr29, codeSeg, 0x8E, 2);  // INTEL RESERVED
    KeSetIDTGate(0x1E, (ulong)isr30, codeSeg, 0x8E, 2);
    KeSetIDTGate(0x1F, (ulong)isr31, codeSeg, 0x8E, 2);  // INTEL RESERVED

    // Set IDT IRQs Gates
    KeSetIDTGate(0x20, (ulong)isr32, codeSeg, 0x8E, 0); // 0 means don't use Interrupt Stack Table
    KeSetIDTGate(0x21, (ulong)isr33, codeSeg, 0x8E, 3);
    KeSetIDTGate(0x22, (ulong)isr34, codeSeg, 0x8E, 3); // NEVER RAISED : cascaded
    KeSetIDTGate(0x23, (ulong)isr35, codeSeg, 0x8E, 3);
    KeSetIDTGate(0x24, (ulong)isr36, codeSeg, 0x8E, 3);
    KeSetIDTGate(0x25, (ulong)isr37, codeSeg, 0x8E, 3);
    KeSetIDTGate(0x26, (ulong)isr38, codeSeg, 0x8E, 3);
    KeSetIDTGate(0x27, (ulong)isr39, codeSeg, 0x8E, 3);
    KeSetIDTGate(0x28, (ulong)isr40, codeSeg, 0x8E, 3);
    KeSetIDTGate(0x29, (ulong)isr41, codeSeg, 0x8E, 3);
    KeSetIDTGate(0x2A, (ulong)isr42, codeSeg, 0x8E, 3);
    KeSetIDTGate(0x2B, (ulong)isr43, codeSeg, 0x8E, 3);
    KeSetIDTGate(0x2C, (ulong)isr44, codeSeg, 0x8E, 3);
    KeSetIDTGate(0x2D, (ulong)isr45, codeSeg, 0x8E, 3);
    KeSetIDTGate(0x2E, (ulong)isr46, codeSeg, 0x8E, 3);
    KeSetIDTGate(0x2F, (ulong)isr47, codeSeg, 0x8E, 3);
    
    // SYSCALL
    KeSetIDTGate(0x80, (ulong)isr128, codeSeg, 0x8E, 3);

    KeIdtIsInitialized++;

    //Setup Early Exception handler
    for (uchar i = 0 ; i < 0x2F ; i++) {
        KeRegisterISR(EarlyExceptionHandler, i);
    }

    KeRegisterISR(KeBrkDumpRegisters, 0x3);
    KeRegisterISR(DoubleFaultHandler, 0x8);
    KeRegisterISR(EarlySyscallHandler, 0x80);

    // Load IDT
    KeLoadIDT();
    //DebugLog("\tInterrupt table initialized at %p\n", _KeIdtPtr.base);
    DebugLog("Interrupts activated\n");
}

//
// Set an interrupt gate
//
void KeSetIDTGate(uchar rank, ulong base, ushort selector, uchar flags, uchar ist)
{
    // Set Base Address
    idt[rank].baseLow = base & 0xFFFF;
    idt[rank].baseMid = (base >> 16) & 0xFFFF;
    idt[rank].baseHigh = (base >> 32) & 0xFFFFFFFF;

    // Set Selector
    idt[rank].selector = selector;
    idt[rank].flags = flags;

    // Set Reserved Areas to Zero
    idt[rank].ist = ist;
    idt[rank].reserved = 0;
}

//
// Enable and initializes the PIC to work correctly
//
static void EnablePIC(void)
{
    // Set ICW1 - begin init of the PIC
    IoWriteByteOnPort(0x20, 0x11);
    IoWriteByteOnPort(0xa0, 0x11);

    // Set ICW2 (IRQ base offsets)
    IoWriteByteOnPort(0x21, 0x20);  // 0x20 is the first free interrupt for IRQ0
    IoWriteByteOnPort(0xa1, 0x28);  // PIC2 is offseted to 0x28, just after PIC1

    // Set ICW3
    IoWriteByteOnPort(0x21, 0x4);   // A slave exists
    IoWriteByteOnPort(0xa1, 0x2);   // You're a slave

    // Set ICW4
    IoWriteByteOnPort(0x21, 0x1);
    IoWriteByteOnPort(0xa1, 0x1);

    // Set OCW1 (interrupt masks)
    IoWriteByteOnPort(0x21, 0xff);
    IoWriteByteOnPort(0xa1, 0xff);

    char readIrqs = IoReadByteFromPort(0x21);
    IoWriteByteOnPort(0x21, 0xFB & readIrqs);     // Enables IRQ forwarding from PIC2 to PIC 1
}

//
// Ends the current interrupt handling
//
void KeSendEOItoPIC(uchar isr)
{
    if(isr >= 8)
        IoWriteByteOnPort(0xa0,0x20);

    IoWriteByteOnPort(0x20,0x20);
}

void KeMaskIRQ(uchar isr)
{
    uchar port;
    uchar value;

    if(isr < 8) {
        port = 0x21;
    } else {
        port = 0xA1;
        isr -= 8;
    }

    value = IoReadByteFromPort(port) | (1 << isr);
    IoWriteByteOnPort(port, value);
    DebugLog("ISR masked : %d\n", isr);
}

void KeUnmaskIRQ(uchar isr)
{
    uchar port;
    uchar value;

    if(isr < 0x8) {
        port = 0x21;
    } else {
        port = 0xA1;
        isr -= 8;
    }

    value = IoReadByteFromPort(port) & ~(1 << isr);
    IoWriteByteOnPort(port, value);
    DebugLog("ISR unmasked : %d\n", isr);
}

void KeEnableNMI(void)
{
    IoWriteByteOnPort(0x70, IoReadByteFromPort(0x70) & 0x7F);
    DebugLog("NMI Interrupts enabled\n");
}

void KeDisableNMI(void)
{
    IoWriteByteOnPort(0x70, IoReadByteFromPort(0x70) | 0x80);
    DebugLog("NMI Interrupts disabled\n");
}


//
// Get the content of a register of the PIC. Parameter is a ocw3 command :
//      - 0x0a : read the IRR
//      - 0x0b : read the ISR
//
static inline ushort KeGetIrqRegister(int ocw3)
{
    IoWriteByteOnPort(0x20, ocw3);
    IoWriteByteOnPort(0xA0, ocw3);
    return ((IoReadByteFromPort(0xA0) << 8) | IoReadByteFromPort(0x20)); // We MUST read the COMMAND PORT
}


//
// The main ISR handler
//
void _KeHandleISR(ISRFrame_t *regs)
{
    if ((regs->intNo >= 0x15) && (regs->intNo <= 0x1D))
        return; // INTEL RESERVED

    if ((regs->intNo == 0x0F) || (regs->intNo == 0x1F))
        return; // INTEL RESERVED

    // Spurious interrupt handling.
    if (regs->intNo >= 0x20 && regs->intNo <= 0x2F && !(KeGetIrqRegister(0x0b) & (1<<(regs->intNo - 0x20)))) {
       KeSpuriousCount++;
       return;
   }

    for (int i = 0; i < isrList.n; i++) {
        if (regs->intNo == isrList.entry[i].isrNo) {
            isrList.entry[i].isr(regs);
            return;
        }
    }

    bprintf(BStdDbg, "[%C%8d%C]\tISR 0x%x %s\n",
            VGA_COLOR_BROWN,
            KeGetTicks(),
            VGA_COLOR_LIGHT_GREY,
            regs->intNo,
            "Unknown ISR Exception");
    KeSendEOItoPIC(regs->intNo);
}

//
// Early CPU Exception handler
//
static void EarlyExceptionHandler(ISRFrame_t *regs)
{
    bprintf(BStdOut, "\n\n%CPANIC\n[ISR 0x%x] Irrecoverable Kernel %s\n\n"
                     "  Error code : 0x%x (%b)",

                     VGA_COLOR_LIGHT_RED,
                     regs->intNo,
                     ExceptionsChar[regs->intNo],
                     regs->ErrorCode,
                     regs->ErrorCode
                 );

    KeBrkDumpRegisters(regs);

    BStdOut->flusher(BStdOut);

    KeHaltCPU();
}

//
// Double Fault handling and stack overflow detection
//
static void DoubleFaultHandler(ISRFrame_t *regs)
{
    bprintf(BStdOut,
            "\n\n%CPANIC\n[ISR 0x8] Irrecoverable Kernel Double Fault Abort\n\n"
                     "  Error code : 0x%x (%b)",

                     VGA_COLOR_LIGHT_RED,
                     regs->ErrorCode,
                     regs->ErrorCode
                 );

    KeBrkDumpRegisters(regs);

    BStdOut->flusher(BStdOut);

    KeHaltCPU();
}

static void EarlySyscallHandler(ISRFrame_t *regs)
{
    DebugLog("Got an early system call !\n");
}

void KeBrkDumpRegisters(ISRFrame_t *regs)
{
    IoDoBeepNoIdt();

    size_t N = 3;
    char *ptr = (char *)lmax((ulong)BStdDbg->buf,
               (ulong)(BStdDbg->wp - BStdDbg->lastLF - (BStdDbg->lineLen * N)));

    bprintf(BStdOut, "\n%C  Debug messages last %d lines: \n  %s\n",
            VGA_COLOR_LIGHT_GREY,
            N,
            ptr);

    bprintf(BStdOut,
                     "%C  RIP: %#016lx   RSP: %#016lx   RBP: %#016lx\n\n"

                     "  SS:  %#016lx   CS:  %#016lx   CR0: %#016lx\n"
                     "  CR2: %#016lx   CR3: %#016lx   CR4: %#016lx\n"
                     "  CR8: %#016lx   EFE: %#016lx   \n\n"

                     "  RAX: %#016lx   RBX: %#016lx   RCX: %#016lx\n"
                     "  RDX: %#016lx   RSI: %#016lx   RDI: %#016lx\n"

                     "  R8:  %#016lx   R9:  %#016lx   R10: %#016lx\n"
                     "  R11: %#016lx   R12: %#016lx   R13: %#016lx\n"
                     "  R14: %#016lx   R15: %#016lx   \n\n"

                     "  RFLAGS: %#022b (%#06x)",
                     VGA_COLOR_LIGHT_RED,
                     regs->rip,
                     regs->rsp,
                     regs->rbp,
                     regs->ss,
                     regs->cs,
                     regs->cr0,
                     regs->cr2,
                     regs->cr3,
                     regs->cr4,
                     regs->cr8,
                     regs->efer,
                     regs->rax,
                     regs->rbx,
                     regs->rcx,
                     regs->rdx,
                     regs->rsi,
                     regs->rdi,
                     regs->r8,
                     regs->r9,
                     regs->r10,
                     regs->r11,
                     regs->r12,
                     regs->r13,
                     regs->r14,
                     regs->r15,
                     regs->rflags,
                     regs->rflags
    );

    BStdOut->flusher(BStdOut);
}