handler.h File Reference

interrupt_handler() Interrupt handler More...

#include "types.h"
#include "machine/core_interrupt.h"

Include dependency graph for handler.h:

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Classes
struct	InterruptContext
	Preserved interrupt context. More...

Functions
void	interrupt_handler (Core::Interrupt::Vector vector, InterruptContext *context)
	High-Level Interrupt Handling.

Constants
void *const	interrupt_entry []
	Array of function pointer to the default low-level interrupt handlers.

Detailed Description

interrupt_handler() Interrupt handler

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Class Documentation

InterruptContext

struct InterruptContext

Preserved interrupt context.

After an interrupt was triggered, the core first saves the basic context (current code- & stack segment, instruction & stack pointer and the status flags register) and looks up the handling function for the vector using the IDT. In StuBS for each vector an own interrupt_entry_VECTOR function (written in assembly in interrupt/handler.asm) was registered during boot by kernel_init(), which all save the scratch registers on the stack before calling the C++ function interrupt_handler(). The high-level handler gets a pointer to the part of the stack which corresponds to the InterruptContext structure as second parameter. After returning from the high-level handler, the previous state is restored from this context (scratch register in assembly and basic context while executing iret) so it can continue transparently at the previous position.

Class Members
uintptr_t	r11	scratch register R11
uintptr_t	r10	scratch register R10
uintptr_t	r9	scratch register R9
uintptr_t	r8	scratch register R8
uintptr_t	rdi	scratch register RDI
uintptr_t	rsi	scratch register RSI
uintptr_t	rdx	scratch register RDX
uintptr_t	rcx	scratch register RCX
uintptr_t	rax	scratch register RAX
uintptr_t	error_code	Error Code.
uintptr_t	ip	Instruction Pointer (at interrupt)
uintptr_t	cs: 16	Code segment (in case of a ring switch it is the segment of the user mode)
uintptr_t	__pad0__: 0	Alignment (due to 16 bit code segment)
uintptr_t	flags	Status flags register.
uintptr_t	sp	Stack pointer (at interrupt)
uintptr_t	ss: 16	Stack segment (in case of a ring switch it is the segment of the user mode)
uintptr_t	__pad1__: 0	Alignment (due to 16 bit stack segment)

Variable Documentation

interrupt_entry

void* const interrupt_entry[]

Array of function pointer to the default low-level interrupt handlers.

The index corresponds to the vectors entry function, e.g. interrupt_entry[6] points to interrupt_entry_6, handling the trap for invalid opcode.

The entry functions and this array are defined in assembly in interrupt/handler.asm and used in kernel_init() to initialize the Interrupt Descriptor Table (IDT).