Add some interrupt handling

kernel/src/arch/CPU.h

@@ -1,6 +1,8 @@
 #pragma once
 #include <Result.h>
 
+struct Registers;
+
 namespace CPU
 {
     Result<const char*> identify();

kernel/src/arch/x86_64/CPU.asm

@@ -1,3 +1,9 @@
+section .data
+global __divisor
+__divisor:
+    dd 0
+
+section .text
 global enable_sse
 enable_sse:
     mov rax, cr0
@@ -45,4 +51,73 @@ global load_tr
 load_tr:
     mov rax, rdi
     ltr ax
-    ret
+    ret
+
+%macro ISR 1
+    global _isr%1
+    _isr%1:
+        push byte 0
+        push byte %1
+        jmp _asm_interrupt_entry
+%endmacro
+
+%macro ISR_ERROR 1
+    global _isr%1
+    _isr%1:
+        push byte %1
+        jmp _asm_interrupt_entry
+%endmacro
+
+%macro IRQ 2
+    global _isr%1
+    _isr%1:
+        push byte %2
+        push byte %1
+        jmp _asm_interrupt_entry
+%endmacro
+
+extern arch_interrupt_entry
+
+_asm_interrupt_entry:
+    push rax
+    push rbx
+    push rcx
+    push rdx
+    push rsi
+    push rdi
+    push rbp
+    push r8
+    push r9
+    push r10
+    push r11
+    push r12
+    push r13
+    push r14
+    push r15
+
+    cld
+
+    mov rdi, rsp
+    call arch_interrupt_entry
+
+    pop r15
+    pop r14
+    pop r13
+    pop r12
+    pop r11
+    pop r10
+    pop r9
+    pop r8
+    pop rbp
+    pop rdi
+    pop rsi
+    pop rdx
+    pop rcx
+    pop rbx
+    pop rax
+
+    add rsp, 16
+
+    iretq
+
+ISR 0 ; divide by zero

kernel/src/arch/x86_64/CPU.cpp

@@ -1,4 +1,5 @@
-#include "arch/CPU.h"
+#include "arch/x86_64/CPU.h"
+#include "arch/Serial.h"
 #include <String.h>
 #include <Types.h>
 #include <cpuid.h>
@@ -147,7 +148,7 @@ struct IDTR
     uint64_t offset;
 } __attribute__((packed));
 
-[[maybe_unused]] static void idt_add_handler(short num, void* handler, u8 type_attr)
+static void idt_add_handler(short num, void* handler, u8 type_attr)
 {
     check(handler != nullptr);
     check(num < 256);
@@ -157,14 +158,38 @@ struct IDTR
     entry_for_handler->set_offset((u64)handler);
 }
 
-static void setup_idt() // FIXME: Add entries to the IDT.
+#define INT(x) extern "C" void _isr##x()
+#define TRAP(x) idt_add_handler(x, (void*)_isr##x, IDT_TA_TrapGate)
+
+INT(0);
+
+static void setup_idt()
 {
+    TRAP(0); // divide by zero
+
     static IDTR idtr;
     idtr.limit = 0x0FFF;
     idtr.offset = (u64)idt;
     asm("lidt %0" : : "m"(idtr));
 }
 
+// Interrupt handling
+
+// Called from _asm_interrupt_entry
+extern "C" void arch_interrupt_entry(Registers* regs)
+{
+    if (regs->isr < 32)
+    {
+        Serial::println("Exception catched! Halting.");
+        CPU::efficient_halt();
+    }
+    else
+    {
+        Serial::println("IRQ catched! Halting.");
+        CPU::efficient_halt();
+    }
+}
+
 // Generic CPU code
 
 static bool test_nx()

kernel/src/arch/x86_64/CPU.h

@@ -0,0 +1,10 @@
+#include "arch/CPU.h"
+#include <Types.h>
+
+struct Registers // Saved CPU registers for x86-64
+{
+    u64 r15, r14, r13, r12, r11, r10, r9, r8;
+    u64 rbp, rdi, rsi, rdx, rcx, rbx, rax;
+    u64 isr, error;
+    u64 rip, cs, rflags, rsp, ss;
+};

kernel/src/main.cpp

@@ -84,7 +84,11 @@ extern "C" [[noreturn]] void _start()
 
     Serial::println("Successfully unmapped address");
 
-    check(false);
+    extern int __divisor; // divisor is defined as 0, we do it this way so the compiler doesn't catch it (this is
+                          // testing exception handling)
+    [[maybe_unused]] volatile int div_rc = 4 / __divisor;
+
+    Serial::println("ERROR: Still here after division by zero");
 
     CPU::efficient_halt();
 }

tools/check-formatting.sh

@@ -4,9 +4,7 @@ source $(dirname $0)/env.sh
 
 cd $LUNA_ROOT
 
-SOURCES=($(find kernel/src -type f | grep "\.c") $(find kernel/include -type f))
+SOURCES=($(find kernel/src -type f | grep -v "\.asm"))
-SOURCES+=($(find libs/libc/src -type f | grep "\.c") $(find libs/libc/include -type f))
-SOURCES+=($(find apps/src -type f))
 
 ALL_OK=1
 

tools/run-clang-format.sh

@@ -5,9 +5,7 @@ source $(dirname $0)/env.sh
 
 cd $LUNA_ROOT
 
-SOURCES=($(find kernel/src -type f | grep "\.c") $(find kernel/include -type f))
+SOURCES=($(find kernel/src -type f | grep -v "\.asm"))
-SOURCES+=($(find libs/libc/src -type f | grep "\.c") $(find libs/libc/include -type f))
-SOURCES+=($(find apps/src -type f))
 
 for f in ${SOURCES[@]}
 do