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/*
* Copyright (c) 2022, Timon Kruiper <timonkruiper@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <Kernel/Arch/CPU.h>
#include <Kernel/Arch/Interrupts.h>
#include <Kernel/Arch/PageFault.h>
#include <Kernel/Arch/TrapFrame.h>
#include <Kernel/Arch/aarch64/InterruptManagement.h>
#include <Kernel/Interrupts/GenericInterruptHandler.h>
#include <Kernel/Interrupts/SharedIRQHandler.h>
#include <Kernel/Interrupts/UnhandledInterruptHandler.h>
#include <Kernel/KSyms.h>
#include <Kernel/Library/Panic.h>
#include <Kernel/Library/StdLib.h>
namespace Kernel {
extern "C" void syscall_handler(TrapFrame const*);
static void dump_exception_syndrome_register(Aarch64::ESR_EL1 const& esr_el1)
{
dbgln("Exception Syndrome: EC({:#b}) IL({:#b}) ISS({:#b}) ISS2({:#b})", esr_el1.EC, esr_el1.IL, esr_el1.ISS, esr_el1.ISS2);
dbgln(" Class: {}", Aarch64::exception_class_to_string(esr_el1.EC));
if (Aarch64::exception_class_is_data_abort(esr_el1.EC))
dbgln(" Data Fault Status Code: {}", Aarch64::data_fault_status_code_to_string(esr_el1.ISS));
if (Aarch64::exception_class_has_set_far(esr_el1.EC))
dbgln(" Faulting Virtual Address: 0x{:x}", Aarch64::FAR_EL1::read().virtual_address);
}
void dump_registers(RegisterState const& regs)
{
auto esr_el1 = Kernel::Aarch64::ESR_EL1::read();
dump_exception_syndrome_register(esr_el1);
// Special registers
Aarch64::SPSR_EL1 spsr_el1 = {};
memcpy(&spsr_el1, (u8 const*)®s.spsr_el1, sizeof(u64));
dbgln("Saved Program Status: (NZCV({:#b}) DAIF({:#b}) M({:#b})) / 0x{:x}", ((regs.spsr_el1 >> 28) & 0b1111), ((regs.spsr_el1 >> 6) & 0b1111), regs.spsr_el1 & 0b1111, regs.spsr_el1);
dbgln("Exception Link Register: 0x{:x}", regs.elr_el1);
dbgln("Stack Pointer (EL0): 0x{:x}", regs.sp_el0);
dbgln(" x0={:p} x1={:p} x2={:p} x3={:p} x4={:p}", regs.x[0], regs.x[1], regs.x[2], regs.x[3], regs.x[4]);
dbgln(" x5={:p} x6={:p} x7={:p} x8={:p} x9={:p}", regs.x[5], regs.x[6], regs.x[7], regs.x[8], regs.x[9]);
dbgln("x10={:p} x11={:p} x12={:p} x13={:p} x14={:p}", regs.x[10], regs.x[11], regs.x[12], regs.x[13], regs.x[14]);
dbgln("x15={:p} x16={:p} x17={:p} x18={:p} x19={:p}", regs.x[15], regs.x[16], regs.x[17], regs.x[18], regs.x[19]);
dbgln("x20={:p} x21={:p} x22={:p} x23={:p} x24={:p}", regs.x[20], regs.x[21], regs.x[22], regs.x[23], regs.x[24]);
dbgln("x25={:p} x26={:p} x27={:p} x28={:p} x29={:p}", regs.x[25], regs.x[26], regs.x[27], regs.x[28], regs.x[29]);
dbgln("x30={:p}", regs.x[30]);
}
static ErrorOr<PageFault> page_fault_from_exception_syndrome_register(VirtualAddress fault_address, Aarch64::ESR_EL1 esr_el1)
{
PageFault fault { fault_address };
u8 data_fault_status_code = esr_el1.ISS & 0x3f;
if (data_fault_status_code >= 0b001100 && data_fault_status_code <= 0b001111) {
fault.set_type(PageFault::Type::ProtectionViolation);
} else if (data_fault_status_code >= 0b000100 && data_fault_status_code <= 0b000111) {
fault.set_type(PageFault::Type::PageNotPresent);
} else {
dbgln("Unknown DFSC: {}", Aarch64::data_fault_status_code_to_string(esr_el1.ISS));
return Error::from_errno(EFAULT);
}
fault.set_access((esr_el1.ISS & (1 << 6)) == (1 << 6) ? PageFault::Access::Write : PageFault::Access::Read);
fault.set_mode(Aarch64::exception_class_is_data_or_instruction_abort_from_lower_exception_level(esr_el1.EC) ? ExecutionMode::User : ExecutionMode::Kernel);
if (Aarch64::exception_class_is_instruction_abort(esr_el1.EC))
fault.set_instruction_fetch(true);
return fault;
}
extern "C" void exception_common(Kernel::TrapFrame* trap_frame);
extern "C" void exception_common(Kernel::TrapFrame* trap_frame)
{
Processor::current().enter_trap(*trap_frame, false);
auto esr_el1 = Kernel::Aarch64::ESR_EL1::read();
auto fault_address = Aarch64::FAR_EL1::read().virtual_address;
Processor::enable_interrupts();
if (Aarch64::exception_class_is_data_abort(esr_el1.EC) || Aarch64::exception_class_is_instruction_abort(esr_el1.EC)) {
auto page_fault_or_error = page_fault_from_exception_syndrome_register(VirtualAddress(fault_address), esr_el1);
if (page_fault_or_error.is_error()) {
dump_registers(*trap_frame->regs);
handle_crash(*trap_frame->regs, "Unknown page fault", SIGSEGV, false);
} else {
auto page_fault = page_fault_or_error.release_value();
page_fault.handle(*trap_frame->regs);
}
} else if (Aarch64::exception_class_is_svc_instruction_execution(esr_el1.EC)) {
syscall_handler(trap_frame);
} else {
dump_registers(*trap_frame->regs);
handle_crash(*trap_frame->regs, "Unexpected exception", SIGSEGV, false);
}
Processor::disable_interrupts();
Processor::current().exit_trap(*trap_frame);
}
static Array<GenericInterruptHandler*, 64> s_interrupt_handlers;
extern "C" void handle_interrupt(TrapFrame&);
extern "C" void handle_interrupt(TrapFrame& trap_frame)
{
Processor::current().enter_trap(trap_frame, true);
for (auto& interrupt_controller : InterruptManagement::the().controllers()) {
auto pending_interrupts = interrupt_controller->pending_interrupts();
// TODO: Add these interrupts as a source of entropy for randomness.
u8 irq = 0;
while (pending_interrupts) {
if ((pending_interrupts & 0b1) != 0b1) {
irq += 1;
pending_interrupts >>= 1;
continue;
}
auto* handler = s_interrupt_handlers[irq];
VERIFY(handler);
handler->increment_call_count();
handler->handle_interrupt(*trap_frame.regs);
handler->eoi();
irq += 1;
pending_interrupts >>= 1;
}
}
Processor::current().exit_trap(trap_frame);
}
// FIXME: Share the code below with Arch/x86_64/Interrupts.cpp
// While refactoring, the interrupt handlers can also be moved into the InterruptManagement class.
GenericInterruptHandler& get_interrupt_handler(u8 interrupt_number)
{
auto*& handler_slot = s_interrupt_handlers[interrupt_number];
VERIFY(handler_slot != nullptr);
return *handler_slot;
}
static void revert_to_unused_handler(u8 interrupt_number)
{
auto handler = new UnhandledInterruptHandler(interrupt_number);
handler->register_interrupt_handler();
}
void register_generic_interrupt_handler(u8 interrupt_number, GenericInterruptHandler& handler)
{
auto*& handler_slot = s_interrupt_handlers[interrupt_number];
if (handler_slot == nullptr) {
handler_slot = &handler;
return;
}
if (handler_slot->type() == HandlerType::UnhandledInterruptHandler) {
auto* unhandled_handler = static_cast<UnhandledInterruptHandler*>(handler_slot);
unhandled_handler->unregister_interrupt_handler();
delete unhandled_handler;
handler_slot = &handler;
return;
}
if (handler_slot->is_shared_handler()) {
VERIFY(handler_slot->type() == HandlerType::SharedIRQHandler);
static_cast<SharedIRQHandler*>(handler_slot)->register_handler(handler);
return;
}
if (!handler_slot->is_shared_handler()) {
if (handler_slot->type() == HandlerType::SpuriousInterruptHandler) {
// FIXME: Add support for spurious interrupts on aarch64
TODO_AARCH64();
}
VERIFY(handler_slot->type() == HandlerType::IRQHandler);
auto& previous_handler = *handler_slot;
handler_slot = nullptr;
SharedIRQHandler::initialize(interrupt_number);
VERIFY(handler_slot);
static_cast<SharedIRQHandler*>(handler_slot)->register_handler(previous_handler);
static_cast<SharedIRQHandler*>(handler_slot)->register_handler(handler);
return;
}
VERIFY_NOT_REACHED();
}
void unregister_generic_interrupt_handler(u8 interrupt_number, GenericInterruptHandler& handler)
{
auto*& handler_slot = s_interrupt_handlers[interrupt_number];
VERIFY(handler_slot != nullptr);
if (handler_slot->type() == HandlerType::UnhandledInterruptHandler)
return;
if (handler_slot->is_shared_handler()) {
VERIFY(handler_slot->type() == HandlerType::SharedIRQHandler);
auto* shared_handler = static_cast<SharedIRQHandler*>(handler_slot);
shared_handler->unregister_handler(handler);
if (!shared_handler->sharing_devices_count()) {
handler_slot = nullptr;
revert_to_unused_handler(interrupt_number);
}
return;
}
if (!handler_slot->is_shared_handler()) {
VERIFY(handler_slot->type() == HandlerType::IRQHandler);
handler_slot = nullptr;
revert_to_unused_handler(interrupt_number);
return;
}
}
void initialize_interrupts()
{
for (u8 i = 0; i < s_interrupt_handlers.size(); ++i) {
auto* handler = new UnhandledInterruptHandler(i);
handler->register_interrupt_handler();
}
}
// Sets the reserved flag on `number_of_irqs` if it finds unused interrupt handler on
// a contiguous range.
ErrorOr<u8> reserve_interrupt_handlers([[maybe_unused]] u8 number_of_irqs)
{
TODO();
return Error::from_errno(EINVAL);
}
}
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