Add IRQHandler class that can be subclasses to handle an IRQ.

Also move Keyboard to a class implementation using this pattern.

Kernel/IRQHandler.cpp

@@ -0,0 +1,25 @@
+#include "IRQHandler.h"
+#include "i386.h"
+#include "PIC.h"
+
+IRQHandler::IRQHandler(byte irq)
+    : m_irqNumber(irq)
+{
+    registerIRQHandler(m_irqNumber, *this);
+}
+
+IRQHandler::~IRQHandler()
+{
+    unregisterIRQHandler(m_irqNumber, *this);
+}
+
+void IRQHandler::enableIRQ()
+{
+    PIC::enable(m_irqNumber);
+}
+
+void IRQHandler::disableIRQ()
+{
+    PIC::disable(m_irqNumber);
+}
+

Kernel/IRQHandler.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include <AK/Types.h>
+
+class IRQHandler {
+public:
+    virtual ~IRQHandler();
+    virtual void handleIRQ() = 0;
+
+    byte irqNumber() const { return m_irqNumber; }
+
+    void enableIRQ();
+    void disableIRQ();
+
+protected:
+    explicit IRQHandler(byte irq);
+
+private:
+    byte m_irqNumber { 0 };
+};
+

Kernel/Keyboard.cpp

@@ -1,11 +1,10 @@
 #include "types.h"
 #include "i386.h"
 #include "IO.h"
-#include "IPC.h"
-#include "Task.h"
 #include "VGA.h"
 #include "PIC.h"
 #include "Keyboard.h"
+#include <AK/Assertions.h>
 
 #define IRQ_KEYBOARD             1
 
@@ -16,36 +15,6 @@
 #define DATA_AVAILABLE           0x01
 #define I8042_ACK                0xFA
 
-extern "C" void handleKeyboardInterrupt();
-extern "C" void keyboard_ISR();
-
-static BYTE s_ledState;
-
-asm(
-    ".globl keyboard_ISR \n"
-    "keyboard_ISR: \n"
-    "    pusha\n"
-    "    pushw %ds\n"
-    "    pushw %es\n"
-    "    pushw %ss\n"
-    "    pushw %ss\n"
-    "    popw %ds\n"
-    "    popw %es\n"
-    "    call handleKeyboardInterrupt\n"
-    "    popw %es\n"
-    "    popw %ds\n"
-    "    popa\n"
-    "    iret\n"
-);
-
-void handleKeyboardInterrupt()
-{
-    IRQHandlerScope scope(IRQ_KEYBOARD);
-    Keyboard::handleInterrupt();
-}
-
-namespace Keyboard {
-
 #define MOD_ALT     1
 #define MOD_CTRL    2
 #define MOD_SHIFT   4
@@ -66,19 +35,18 @@ static char shift_map[0x100] =
     'Z', 'X', 'C', 'V', 'B', 'N', 'M', '<', '>', '?',
 };
 
-static BYTE s_modifiers;
 
-void handleInterrupt()
+void Keyboard::handleIRQ()
 {
     while (IO::in8(0x64) & 1) {
         BYTE ch = IO::in8(0x60);
         switch (ch) {
-        case 0x38: s_modifiers |= MOD_ALT; break;
-        case 0xB8: s_modifiers &= ~MOD_ALT; break;
-        case 0x1D: s_modifiers |= MOD_CTRL; break;
-        case 0x9D: s_modifiers &= ~MOD_CTRL; break;
-        case 0x2A: s_modifiers |= MOD_SHIFT; break;
-        case 0xAA: s_modifiers &= ~MOD_SHIFT; break;
+        case 0x38: m_modifiers |= MOD_ALT; break;
+        case 0xB8: m_modifiers &= ~MOD_ALT; break;
+        case 0x1D: m_modifiers |= MOD_CTRL; break;
+        case 0x9D: m_modifiers &= ~MOD_CTRL; break;
+        case 0x2A: m_modifiers |= MOD_SHIFT; break;
+        case 0xAA: m_modifiers &= ~MOD_SHIFT; break;
         case 0x1C: /* enter */ kprintf("\n"); break;
         case 0xFA: /* i8042 ack */ break;
         default:
@@ -86,50 +54,30 @@ void handleInterrupt()
                 // key has been depressed
                 break;
             }
-            if (!s_modifiers)
+            if (!m_modifiers)
                 kprintf("%c", map[ch]);
-            else if (s_modifiers & MOD_SHIFT)
+            else if (m_modifiers & MOD_SHIFT)
                 kprintf("%c", shift_map[ch]);
-            else if (s_modifiers & MOD_CTRL)
+            else if (m_modifiers & MOD_CTRL)
                 kprintf("^%c", shift_map[ch]);
         }
         //break;
     }
 }
 
-void initialize()
+Keyboard::Keyboard()
+    : IRQHandler(IRQ_KEYBOARD)
 {
-    s_modifiers = 0;
-    s_ledState = 0;
-
     // Empty the buffer of any pending data.
     // I don't care what you've been pressing until now!
     while (IO::in8(I8042_STATUS ) & DATA_AVAILABLE)
         IO::in8(I8042_BUFFER);
 
-    registerInterruptHandler(IRQ_VECTOR_BASE + IRQ_KEYBOARD, keyboard_ISR);
-
-    PIC::enable(IRQ_KEYBOARD);
+    enableIRQ();
 }
 
-void setLED(LED led)
+Keyboard::~Keyboard()
 {
-    s_ledState |= (BYTE)led & 7;
-
-    while (IO::in8(I8042_STATUS) & DATA_AVAILABLE);
-    IO::out8(I8042_BUFFER, SET_LEDS);
-    while (IO::in8(I8042_BUFFER) != I8042_ACK);
-    IO::out8(I8042_BUFFER, s_ledState);
+    ASSERT_NOT_REACHED();
 }
 
-void unsetLED(LED led)
-{
-    s_ledState &= ~((BYTE)led & 7);
-
-    while (IO::in8(I8042_STATUS) & DATA_AVAILABLE);
-    IO::out8(I8042_BUFFER, SET_LEDS);
-    while (IO::in8(I8042_BUFFER) != I8042_ACK);
-    IO::out8(I8042_BUFFER, s_ledState);
-}
-
-}

Kernel/Keyboard.h

@@ -1,16 +1,16 @@
 #pragma once
 
-namespace Keyboard {
+#include <AK/Types.h>
+#include "IRQHandler.h"
 
-enum class LED {
-    ScrollLock = 1 << 0,
-    NumLock    = 1 << 1,
-    CapsLock   = 1 << 2,
+class Keyboard final : public IRQHandler {
+public:
+    virtual ~Keyboard() override;
+    Keyboard();
+
+private:
+    virtual void handleIRQ() override;
+
+    byte m_modifiers { 0 };
 };
 
-void initialize();
-void setLED(LED);
-void unsetLED(LED);
-void handleInterrupt();
-
-}

Kernel/Makefile

@@ -19,7 +19,8 @@ KERNEL_OBJS = \
        Userspace.o \
        IDEDiskDevice.o \
        MemoryManager.o \
-       Console.o
+       Console.o \
+       IRQHandler.o
 
 VFS_OBJS = \
     ../VirtualFileSystem/DiskDevice.o \

Kernel/i386.cpp

@@ -5,6 +5,8 @@
 #include "Assertions.h"
 #include "Task.h"
 #include "MemoryManager.h"
+#include "IRQHandler.h"
+#include "PIC.h"
 
 struct DescriptorTablePointer {
     WORD size;
@@ -16,6 +18,8 @@ static DescriptorTablePointer s_gdtr;
 static Descriptor* s_idt;
 static Descriptor* s_gdt;
 
+static IRQHandler** s_irqHandler;
+
 static WORD s_gdtLength;
 
 WORD allocateGDTEntry()
@@ -27,6 +31,26 @@ WORD allocateGDTEntry()
     return newGDTEntry;
 }
 
+extern "C" void handleIRQ();
+extern "C" void commonIRQEntry();
+
+asm(
+    ".globl commonIRQEntry\n"
+    "commonIRQEntry: \n"
+    "    pusha\n"
+    "    pushw %ds\n"
+    "    pushw %es\n"
+    "    pushw %ss\n"
+    "    pushw %ss\n"
+    "    popw %ds\n"
+    "    popw %es\n"
+    "    call handleIRQ\n"
+    "    popw %es\n"
+    "    popw %ds\n"
+    "    popa\n"
+    "    iret\n"
+);
+
 extern volatile dword exception_state_dump;
 extern volatile word exception_code;
 asm(
@@ -290,6 +314,20 @@ static void unimp_trap()
     HANG;
 }
 
+void registerIRQHandler(byte irq, IRQHandler& handler)
+{
+    ASSERT(!s_irqHandler[irq]);
+    s_irqHandler[irq] = &handler;
+    kprintf("irq handler for %u: %p\n", irq, &handler);
+    registerInterruptHandler(IRQ_VECTOR_BASE + irq, commonIRQEntry);
+}
+
+void unregisterIRQHandler(byte irq, IRQHandler& handler)
+{
+    ASSERT(s_irqHandler[irq] == &handler);
+    s_irqHandler[irq] = nullptr;
+}
+
 void registerInterruptHandler(BYTE index, void (*f)())
 {
     s_idt[index].low = 0x00080000 | LSW((f));
@@ -351,6 +389,11 @@ void idt_init()
 
     registerInterruptHandler(0x57, irq7_handler);
 
+    s_irqHandler = new IRQHandler*[16];
+    for (byte i = 0; i < 16; ++i) {
+        s_irqHandler[i] = nullptr;
+    }
+
     flushIDT();
 }
 
@@ -358,3 +401,25 @@ void loadTaskRegister(WORD selector)
 {
     asm("ltr %0"::"r"(selector));
 }
+
+void handleIRQ()
+{
+    WORD isr = PIC::getISR();
+    if (!isr) {
+        kprintf("Spurious IRQ\n");
+        return;
+    }
+
+    byte irq;
+    for (byte i = 0; i < 16; ++i) {
+        if (isr & (1 << i)) {
+            irq = i;
+            break;
+        }
+    }
+
+    if (s_irqHandler[irq])
+        s_irqHandler[irq]->handleIRQ();
+    PIC::eoi(irq);
+}
+

Kernel/i386.h

@@ -55,10 +55,14 @@ union Descriptor {
     }
 } PACKED;
 
+class IRQHandler;
+
 void gdt_init();
 void idt_init();
 void registerInterruptHandler(BYTE number, void (*f)());
 void registerUserCallableInterruptHandler(BYTE number, void (*f)());
+void registerIRQHandler(BYTE number, IRQHandler&);
+void unregisterIRQHandler(BYTE number, IRQHandler&);
 void flushIDT();
 void flushGDT();
 void loadTaskRegister(WORD selector);

Kernel/init.cpp

@@ -27,25 +27,8 @@
 #include "Console.h"
 
 #define TEST_VFS
-#define TEST_ELF_LOADER
-#define TEST_CRASHY_USER_PROCESSES
-
-#if 0
-/* Keyboard LED disco task ;^) */
-
-static void led_disco() NORETURN;
-
-static void led_disco()
-{
-    BYTE b = 0;
-    for (;;) {
-        sleep(0.5 * TICKS_PER_SECOND);
-        Keyboard::unsetLED((Keyboard::LED)b++);
-        b &= 7;
-        Keyboard::setLED((Keyboard::LED)b);
-    }
-}
-#endif
+//#define TEST_ELF_LOADER
+//#define TEST_CRASHY_USER_PROCESSES
 
 static void motd_main() NORETURN;
 static void motd_main()
@@ -115,7 +98,6 @@ static void init_stage2() NORETURN;
 static void init_stage2()
 {
     kprintf("init stage2...\n");
-    Keyboard::initialize();
 
     // Anything that registers interrupts goes *after* PIC and IDT for obvious reasons.
     Syscall::initialize();
@@ -192,10 +174,14 @@ static void init_stage2()
 
     kprintf("init stage2 is done!\n");
 
+#if 0
+    // It would be nice to exit this process, but right now it instantiates all kinds of things.
+    // At the very least it needs to be made sure those things stick around as appropriate.
     DO_SYSCALL_A1(Syscall::PosixExit, 413);
 
     kprintf("uh, we're still going after calling sys$exit...\n");
     HANG;
+#endif
 
     for (;;) {
         asm("hlt");
@@ -217,6 +203,8 @@ void init()
 
     MemoryManager::initialize();
 
+    auto keyboard = make<Keyboard>();
+
     PIT::initialize();
 
     memset(&system, 0, sizeof(system));