added some interrupt handler functions, handling unhandled exceptions with panic,

delegating to sub interrupt handlers from main interrupt handler

3 files changed, 62 insertions, 14 deletions

diff --git a/src/interrupts.c b/src/interrupts.c
index d4c84ba..c04eb59 100644
--- a/src/interrupts.c
+++ b/src/interrupts.c
@@ -54,26 +54,34 @@
 #define ICW4_BUFFER 0x08
 #define ICW4_FULLY_NESTED 0x10
 
+// must be global: when called via assembly code we loose the context
+// of the interrupt handler structure
+interrupt_t interrupt;
+
 void interrupts_init( interrupt_t *interrupt )
 {
 	memset( interrupt, 0, sizeof( interrupt_t ) );
 
-	for( int i = 0; i < NOF_INTERRUPT_GATES; i++ ) {
+	for( int i = 0; i < NOF_INTERRUPTS; i++ ) {
 		interrupts_register_interrupt( interrupt, i, GDT_CODE_SEGMENT_SELECTOR,
-			&interrupts_ignore_request, KERNEL_RING, IDT_TYPE_INTERRUPT_GATE );
+			&interrupts_ignore_request, KERNEL_RING, IDT_TYPE_INTERRUPT_GATE,
+			NULL );		
 	}
 
 	// divide-by-zero exception 0x00
 	interrupts_register_interrupt( interrupt, 0x00, GDT_CODE_SEGMENT_SELECTOR,
-		&interrupts_handle_exception_0x00, KERNEL_RING, IDT_TYPE_INTERRUPT_GATE );
+		&interrupts_handle_exception_0x00, KERNEL_RING, IDT_TYPE_INTERRUPT_GATE,
+		&interrupts_exception_division_by_zero );
 
 	// IRQ 0 - PIT - programmable interrupt timer
 	interrupts_register_interrupt( interrupt, IRQ_BASE + 0x00, GDT_CODE_SEGMENT_SELECTOR,
-		&interrupts_handle_irq_0x00, KERNEL_RING, IDT_TYPE_INTERRUPT_GATE );
+		&interrupts_handle_irq_0x00, KERNEL_RING, IDT_TYPE_INTERRUPT_GATE,
+		&interrupts_interrupt_PIT );
 
 	// IRQ 1 - keyboard
 	interrupts_register_interrupt( interrupt, IRQ_BASE + 0x01, GDT_CODE_SEGMENT_SELECTOR,
-		&interrupts_handle_irq_0x01, KERNEL_RING, IDT_TYPE_INTERRUPT_GATE );
+		&interrupts_handle_irq_0x01, KERNEL_RING, IDT_TYPE_INTERRUPT_GATE,
+		&interrupts_interrupt_keyboard );
 	
 	port8_init( &interrupt->PIC_master_control, 0x20 );
 	port8_init( &interrupt->PIC_master_data, 0x21 );
@@ -106,22 +114,52 @@ void interrupts_init( interrupt_t *interrupt )
 
 void interrupts_register_interrupt( interrupt_t *interrupts, 
 	uint8_t interrupt_no, uint16_t gdt_code_segment_selector,
-	void (*handler)( ), uint8_t privilege_level, uint8_t descriptor_type )
+	void (*helper_handler)( ), uint8_t privilege_level, uint8_t descriptor_type,
+	interrupt_handler_t handler )
 {
 	interrupt_gate_descriptor_t *descr = &interrupts->descriptor_table[interrupt_no];
 	
-	descr->handler_address_low_bits = ( (uint32_t )handler ) & 0xFFFF;
-	descr->handler_address_high_bits = ( ( (uint32_t )handler ) >> 16 ) & 0xFFFF;
+	descr->handler_address_low_bits = ( (uint32_t )helper_handler ) & 0xFFFF;
+	descr->handler_address_high_bits = ( ( (uint32_t )helper_handler ) >> 16 ) & 0xFFFF;
 	descr->gdt_code_segment_selector = gdt_code_segment_selector;
 	descr->access = IDT_PRESENT_BIT | (( privilege_level & 0x3 ) << 5 ) | descriptor_type;
 	descr->reserved = 0;
+	
+	interrupts->interrupt_handler[interrupt_no] = handler;
+}
+
+uint32_t interrupts_exception_division_by_zero( uint32_t esp )
+{
+	// TODO: caused by kernel code or user land code? or a task we can kill?
+	// For now, the kernel has no task management, so we panic
+	kernel_panic( "Division by zero with ESP 0x%X\n", esp );	
+	
+	return esp;
 }
 
+uint32_t interrupts_interrupt_PIT( uint32_t esp )
+{
+	puts( "PIT PIT PIT PIT PIT PIT PIT" );
+	return esp;
+}
+
+uint32_t interrupts_interrupt_keyboard( uint32_t esp )
+{
+	puts( "KBD KBD KBD KBD KBD KBD KBD" );
+	return esp;
+}
+
+
 uint32_t interrupts_handle_interrupt( uint8_t interrupt_no, uint32_t esp )
 {
+	interrupt_handler_t handler = interrupt.interrupt_handler[interrupt_no];
+	
+	if( handler != NULL ) {
+		uint32_t new_esp = handler( esp );
+		return new_esp;
+	}
+	
 	kernel_panic( "Unhandled interrupt 0x%X with ESP 0x%X\n", interrupt_no, esp );
 	
-	// for now, we are using the same stack for kernel and interrupt
-	// handlers (n task switching)
 	return esp;
 }
diff --git a/src/interrupts.h b/src/interrupts.h
index ec408f7..0b514ea 100644
--- a/src/interrupts.h
+++ b/src/interrupts.h
@@ -26,7 +26,7 @@ typedef struct interrupt_gate_descriptor_t {
 #pragma pack()
 #endif
 
-#define NOF_INTERRUPT_GATES 256
+#define NOF_INTERRUPTS 256
 
 #if defined( __TINYC__ )
 #pragma pack(1)
@@ -41,9 +41,12 @@ typedef struct {
 #pragma pack()
 #endif
 
+typedef uint32_t (*interrupt_handler_t)( uint32_t esp );
+
 typedef struct {
 	interrupt_descriptor_table_pointer_t idt_pointer;
-	interrupt_gate_descriptor_t descriptor_table[NOF_INTERRUPT_GATES];
+	interrupt_gate_descriptor_t descriptor_table[NOF_INTERRUPTS];
+	interrupt_handler_t interrupt_handler[NOF_INTERRUPTS];
 	port8_t PIC_master_control;
 	port8_t PIC_master_data;
 	// since PC/AT we always have a slave PIC, we don't support the PC/XT architecture
@@ -52,16 +55,24 @@ typedef struct {
 	port8_t PIC_slave_data;
 } interrupt_t;
 
+extern interrupt_t interrupt;
+
 void interrupts_enable( void );
 void interrupts_disable( void );
 void interrupts_init( interrupt_t *interrupt );
 void interrupts_register_interrupt( interrupt_t *interrupt,
 	uint8_t interrupt_no, uint16_t gdt_code_segment_selector,
-	void (*handler)( ), uint8_t privilege_level, uint8_t descriptor_type );
+	void (*helper_handler)( ), uint8_t privilege_level, uint8_t descriptor_type,
+	interrupt_handler_t handler );
 void interrupts_load_idt( interrupt_descriptor_table_pointer_t *idt_pointer );
 
 uint32_t interrupts_handle_interrupt( uint8_t interrupt_no, uint32_t esp );
 
+uint32_t interrupts_exception_division_by_zero( uint32_t esp );
+
+uint32_t interrupts_interrupt_PIT( uint32_t esp );
+uint32_t interrupts_interrupt_keyboard( uint32_t esp );
+
 void interrupts_ignore_request( );
 void interrupts_handle_exception_0x00( );
 void interrupts_handle_irq_0x00( );
diff --git a/src/kernel.c b/src/kernel.c
index e33d509..ceb1380 100644
--- a/src/kernel.c
+++ b/src/kernel.c
@@ -32,7 +32,6 @@ void entry( void )
 	printf( "Kernel code and data is at 0x%X, kernel stack at 0x%X\n", 0x8400, 0x90000 );
 
 	puts( "Initializing interrupts" );
-	interrupt_t interrupt;
 	interrupts_init( &interrupt );
 
 	// exit point in case of kernel panic, do this as soon as