Interrupts - x86 specific

Collaboration diagram for Interrupts - x86 specific:

Data Structures
struct	idtr
	The location of the IDT is kept inside the IDTR (IDT register). More...
struct	idt_descriptor
	inside the IDT More...
struct	interrupt_frame
	Frame passed onto the interrupt handlers by our stub handler. More...
struct	interrupt_frame::registers_dump
	Dump of the process's registers. More...
struct	interrupt_frame::cpu_interrupt_frame
	Default x86 interrupt frame pushed by the cpu Intel developper manual, figure 6-4. More...

Enumerations
enum	x86_exceptions
	List of all x86 CPU exceptions Intel developper manual, Table 6-1.
enum	idt_gate_type
	The different types of interrupt gates Intel developper manual, section 6-11.

Functions
void	idt_log (void)
	Print the content of the IDT and IDTR.

Variables
u16	idtr::size
	Size of the IDT.
u32	idtr::offset
	Linear address of the IDT
u16	idt_descriptor::offset_low
	16 lower bits of the handler function's address
segment_selector	idt_descriptor::segment
	Selector for the segment inside which we want to run the handler.
u8	idt_descriptor::access
	Acess restriction flags for this interrupt
u16	idt_descriptor::offset_high
	16 higher bits of the handler function's address
u32	interrupt_frame::nr
	Interrupt number (pushed by our stub)
u32	interrupt_frame::error
	Error code for this exception (pushed by our stub)

Detailed Description

x86 specific interrupt interface implentation

Design

On x86 the interrupts are set-up using an Interrupt Descriptor Table.

This table can be located anywhere in memory and is pointed to by the address inside the IDTR register. It contains a pointer to each interrupt's specific handler, as well as information about how we want to run the interrupt (should never change).

Despite that, for conviniency, we define a common stub handler for each known CPU interrupts, which pushes additional information about the interrupt, and eventually calls the actual handler (if we defined one). The actual interrupts are software defined, located inside a static array and can be modified at will using interrupts_set_handler..

This lets us have more control on how we handle the interrupts.

See also

Intel developper manual, section 6

OsDev - IDT