paulbergmann_mpstubs/machine/core_interrupt.h

131 lines
5.2 KiB
C++

/*! \file
* \brief \ref Core::Interrupt "Interrupt control" and \ref Core::Interrupt::Vector "interrupt vector list"
*/
#pragma once
#include "types.h"
namespace Core {
/*! \brief Exception and Interrupt control
*
* \see [ISDMv3, Chapter 6 Interrupt and Exception Handling](intel_manual_vol3.pdf#page=185)
*/
namespace Interrupt {
/*! \brief Bit in `FLAGS` register corresponding to the current interrupt state
*/
const uintptr_t FLAG_ENABLE = 1 << 9;
/*! \brief List of used interrupt vectors.
*
* The exception vectors from `0` to `31` are reserved for traps, faults and aborts.
* Their behavior is different for each exception, some push an *error code*,
* some are not recoverable.
*
* The vectors from `32` to `255` are user defined interrupts.
*
* \see [ISDMv3, 6.15 Exception and Interrupt Reference](intel_manual_vol3.pdf#page=203)
*/
enum Vector {
// Predefined Exceptions
DIVISON_BY_ZERO = 0, ///< Divide-by-zero Error (at a `DIV`/`IDIV` instruction)
DEBUG = 1, ///< Debug exception
NON_MASKABLE_INTERRUPT = 2, ///< Non Maskable Interrupt
BREAKPOINT = 3, ///< Breakpoint exception (used for debugging)
OVERFLOW = 4, ///< Overflow exception (at `INTO` instruction)
BOUND_RANGE_EXCEEDED = 5, ///< Bound Range Exceeded (at `BOUND` instruction)
INVALID_OPCODE = 6, ///< Opcode at Instruction Pointer is invalid (you probably shouldn't be here)
DEVICE_NOT_AVAILABLE = 7, ///< FPU "FPU/MMX/SSE" instruction but corresponding extension not activate
DOUBLE_FAULT = 8, ///< Exception occurred while trying to call exception/interrupt handler
// Coprocessor Segment Overrun (Legacy)
INVALID_TSS = 10, ///< Invalid Task State Segment selector (see error code for index)
SEGMENT_NOT_PRESENT = 11, ///< Segment not available (see error code for selector index)
STACK_SEGMENT_FAULT = 12, ///< Stack segment not available or invalid (see error code for selector index)
GENERAL_PROTECTION_FAULT = 13, ///< Operation not allowed (see error code for selector index)
PAGE_FAULT = 14, ///< Operation on Page (r/w/x) not allowed for current privilege (error code + `cr2`)
// reserved (15)
FLOATING_POINT_EXCEPTION = 16, ///< x87 FPU error (at `WAIT`/`FWAIT`), accidentally \ref Core::CR0_NE set?
ALIGNMENT_CHECK = 17, ///< Unaligned memory access in userspace (Exception activated by \ref Core::CR0_AM)
MACHINE_CHECK = 18, ///< Model specific exception
SIMD_FP_EXCEPTION = 19, ///< SSE/MMX error (if \ref Core::CR4_OSXMMEXCPT activated)
// reserved (20 - 31)
EXCEPTIONS = 32, ///< Number of exceptions
// Interrupts
TIMER = 32, ///< Periodic CPU local \ref LAPIC::Timer interrupt
KEYBOARD = 33, ///< Keyboard interrupt (key press / release)
GDB = 35, ///< Inter-processor interrupt to stop other CPUs for debugging in \ref GDB
ASSASSIN = 100, ///< Inter-processor interrupt to immediately stop threads running on other CPUs
WAKEUP = 101, ///< Inter-processor interrupt to WakeUp sleeping CPUs
VECTORS = 256 ///< Number of interrupt vectors
};
/*! \brief Check if interrupts are enabled on this CPU
*
* This is done by pushing the `FLAGS` register onto stack,
* reading it into a register and checking the corresponding bit.
*
* \return `true` if enabled, `false` if disabled
*/
inline bool isEnabled() {
uintptr_t out;
asm volatile (
"pushf\n\t"
"pop %0\n\t"
: "=r"(out)
:
: "memory"
);
return (out & FLAG_ENABLE) != 0;
}
/*! \brief Allow interrupts
*
* Enables interrupt handling by executing the instruction `sti`.
* Since this instruction is delayed by one cycle, an subsequent `nop` is executed
* (to ensure deterministic behavior, independent from the compiler generated code)
*
* A pending interrupt (i.e., those arriving while interrupts were disabled) will
* be delivered after re-enabling interrupts.
*
* \see [ISDMv2, Chapter 4. STI - Set Interrupt Flag](intel_manual_vol2.pdf#page=1297)
*/
inline void enable() {
asm volatile("sti\n\t nop\n\t" : : : "memory");
}
/*! \brief Forbid interrupts
*
* Prevents interrupt handling by executing the instruction `cli`.
* Will return the previous interrupt state.
* \return `true` if interrupts were enabled at the time of executing this function,
* `false` if they were already disabled.
*
* \see [ISDMv2, Chapter 3. CLI - Clear Interrupt Flag](intel_manual_vol2.pdf#page=245)
*/
inline bool disable() {
bool enabled = isEnabled();
asm volatile ("cli\n\t" : : : "memory");
return enabled;
}
/*! \brief Restore interrupt
*
* Restore the interrupt state to the state prior to calling \ref disable() by using its return value.
*
* \note This function will never disable interrupts, even if val is false!
* This function is designed to allow nested disabling and restoring of the interrupt state.
*
* \param val if set to `true`, interrupts will be enabled; nothing will happen on false.
*/
inline void restore(bool val) {
if (val) {
enable();
}
}
} // namespace Interrupt
} // namespace Core