banan-os/kernel/kernel/Scheduler.cpp

132 lines
3.2 KiB
C++

#include <kernel/Arch.h>
#include <kernel/InterruptController.h>
#include <kernel/Scheduler.h>
namespace Kernel
{
static Scheduler* s_instance = nullptr;
extern "C" void start_thread(uintptr_t arg0, uintptr_t arg1, uintptr_t arg2, uintptr_t arg3, uintptr_t rsp, uintptr_t rip);
extern "C" void continue_thread(uintptr_t rsp, uintptr_t rip);
extern "C" uintptr_t read_rip();
void Scheduler::initialize()
{
ASSERT(!s_instance);
s_instance = new Scheduler();
ASSERT(s_instance);
MUST(s_instance->add_thread(BAN::Function<void()>([] { for(;;) asm volatile("hlt"); })));
}
Scheduler& Scheduler::get()
{
ASSERT(s_instance);
return *s_instance;
}
const Thread& Scheduler::current_thread() const
{
return *m_current_iterator;
}
void Scheduler::reschedule()
{
ASSERT(InterruptController::get().is_in_service(PIT_IRQ));
InterruptController::get().eoi(PIT_IRQ);
uint64_t current_time = PIT::ms_since_boot();
if (m_last_reschedule + ms_between_switch > current_time)
return;
m_last_reschedule = current_time;
for (Thread& thread : m_threads)
if (thread.state() == Thread::State::Sleeping)
thread.set_state(Thread::State::Paused);
switch_thread();
}
void Scheduler::switch_thread()
{
uintptr_t rsp, rip;
push_callee_saved();
if (!(rip = read_rip()))
{
pop_callee_saved();
return;
}
read_rsp(rsp);
ASSERT(m_threads.size() > 1);
Thread& current = *m_current_iterator;
//if (m_threads.size() == 2 && current.id() != 0 && current.state() == Thread::State::Running)
// return;
if (current.state() == Thread::State::Done)
{
m_threads.remove(m_current_iterator);
m_current_iterator = m_threads.begin();
}
else
{
current.set_rsp(rsp);
current.set_rip(rip);
if (current.state() != Thread::State::Sleeping)
current.set_state(Thread::State::Paused);
}
auto next_iterator = m_current_iterator;
if (++next_iterator == m_threads.end())
next_iterator = ++m_threads.begin();
if (next_iterator->state() == Thread::State::Sleeping)
next_iterator = m_threads.begin();
Thread& next = *next_iterator;
m_current_iterator = next_iterator;
switch (next.state())
{
case Thread::State::NotStarted:
next.set_state(Thread::State::Running);
start_thread(next.args()[0], next.args()[1], next.args()[2], next.args()[3], next.rsp(), next.rip());
break;
case Thread::State::Paused:
next.set_state(Thread::State::Running);
continue_thread(next.rsp(), next.rip());
break;
case Thread::State::Sleeping: ASSERT(false);
case Thread::State::Running: ASSERT(false);
case Thread::State::Done: ASSERT(false);
}
ASSERT(false);
}
void Scheduler::set_current_thread_sleeping()
{
asm volatile("cli");
m_current_iterator->set_state(Thread::State::Sleeping);
switch_thread();
asm volatile("sti");
}
void Scheduler::start()
{
ASSERT(m_threads.size() > 1);
m_current_iterator = m_threads.begin();
Thread& current = *m_current_iterator;
ASSERT(current.state() == Thread::State::NotStarted);
current.set_state(Thread::State::Running);
const uintptr_t* args = current.args();
start_thread(args[0], args[1], args[2], args[3], current.rsp(), current.rip());
ASSERT(false);
}
}