Function SyscallHandler

Kernel/src/arch/x86_64/syscalls.cpp:2719–2739

int lastSyscall = 0;
extern "C"
void SyscallHandler(regs64_t* regs) {
	if (regs->rax >= NUM_SYSCALLS) // If syscall is non-existant then return
		return;
		
	asm("sti"); // By reenabling interrupts, a thread in a syscall can be preempted

	thread_t* thread = GetCPULocal()->currentThread;
	if(!syscalls[regs->rax]) return;
	if(thread->state == ThreadStateZombie) for(;;);

	uint64_t rsp = 0;
	asm volatile("mov %%rsp, %0" : "=r"(rsp));

	IF_DEBUG((rsp < KERNEL_VIRTUAL_BASE), {
		Log::Info("warning: call: %d, thread rip: %x, kstack: %x, kernel rsp: %x, tss rsp0: %x, thread cs: %x, thread ss: %x", regs->rax, regs->rip, GetCPULocal()->currentThread->kernelStack, rsp, GetCPULocal()->tss.rsp0, regs->cs, regs->ss);
	});

	acquireLock(&thread->lock);
	regs->rax = syscalls[regs->rax](regs); // Call syscall
	releaseLock(&thread->lock);
}