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Finally unbreak the colonel process and make it the true idle process.

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This commit is contained in:
Andreas Kling 2018-11-07 23:13:38 +01:00
parent 440029c9d1
commit 43f40a3050
4 changed files with 59 additions and 52 deletions
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78
Kernel/Scheduler.cpp
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@ -10,6 +10,12 @@ static const dword time_slice = 5; // *10 = 50ms
Process* current;
static Process* s_colonel_process;
struct TaskRedirectionData {
word selector;
TSS32 tss;
};
static TaskRedirectionData s_redirection;
bool Scheduler::pick_next()
{
ASSERT_INTERRUPTS_DISABLED();
@ -50,6 +56,16 @@ bool Scheduler::pick_next()
return true;
}
if (process.state() == Process::ExecPhase1) {
process.set_state(Process::ExecPhase2);
return true;
}
if (process.state() == Process::ExecPhase2) {
process.set_state(Process::Runnable);
return true;
}
// Forgive dead orphans.
if (process.state() == Process::Dead) {
if (!Process::from_pid(process.ppid()))
@ -57,11 +73,11 @@ bool Scheduler::pick_next()
}
// Release the forgiven.
Process::for_each_in_state(Process::Forgiven, [] (auto& process) {
if (process.state() == Process::Forgiven) {
g_processes->remove(&process);
g_dead_processes->append(&process);
return true;
});
};
return true;
});
@ -104,25 +120,13 @@ bool Scheduler::pick_next()
if (process->state() == Process::Runnable || process->state() == Process::Running) {
#ifdef SCHEDULER_DEBUG
dbgprintf("switch to %s(%u)\n", process->name().characters(), process->pid());
dbgprintf("switch to %s(%u) @ %w:%x\n", process->name().characters(), process->pid(), process->tss().cs, process->tss().eip);
#endif
return context_switch(*process);
}
if (process == prevHead) {
// Back at process_head, nothing wants to run.
kprintf("Nothing wants to run!\n");
kprintf("PID OWNER STATE NSCHED NAME\n");
for (auto* process = g_processes->head(); process; process = process->next()) {
kprintf("%w %w:%w %b %w %s\n",
process->pid(),
process->uid(),
process->gid(),
process->state(),
process->timesScheduled(),
process->name().characters());
}
kprintf("Switch to kernel process @ %w:%x\n", s_colonel_process->tss().cs, s_colonel_process->tss().eip);
// Back at process_head, nothing wants to run. Send in the colonel!
return context_switch(*s_colonel_process);
}
}
@ -214,38 +218,34 @@ int sched_yield()
return Scheduler::yield();
}
static void redo_colonel_process_tss()
static void initialize_redirection()
{
if (!s_colonel_process->selector())
s_colonel_process->setSelector(gdt_alloc_entry());
auto& tssDescriptor = getGDTEntry(s_colonel_process->selector());
tssDescriptor.setBase(&s_colonel_process->tss());
tssDescriptor.setLimit(0xffff);
tssDescriptor.dpl = 0;
tssDescriptor.segment_present = 1;
tssDescriptor.granularity = 1;
tssDescriptor.zero = 0;
tssDescriptor.operation_size = 1;
tssDescriptor.descriptor_type = 0;
tssDescriptor.type = 9;
auto& descriptor = getGDTEntry(s_redirection.selector);
descriptor.setBase(&s_redirection.tss);
descriptor.setLimit(0xffff);
descriptor.dpl = 0;
descriptor.segment_present = 1;
descriptor.granularity = 1;
descriptor.zero = 0;
descriptor.operation_size = 1;
descriptor.descriptor_type = 0;
descriptor.type = 9;
flushGDT();
}
void Scheduler::prepare_for_iret_to_new_process()
{
redo_colonel_process_tss();
s_colonel_process->tss().backlink = current->selector();
load_task_register(s_colonel_process->selector());
auto& descriptor = getGDTEntry(s_redirection.selector);
descriptor.type = 9;
s_redirection.tss.backlink = current->selector();
load_task_register(s_redirection.selector);
}
void Scheduler::prepare_to_modify_own_tss()
{
// This ensures that a process modifying its own TSS in order to yield()
// and end up somewhere else doesn't just end up right after the yield().
load_task_register(s_colonel_process->selector());
load_task_register(s_redirection.selector);
}
static void hlt_loop()
@ -257,8 +257,10 @@ static void hlt_loop()
void Scheduler::initialize()
{
memset(&s_redirection, 0, sizeof(s_redirection));
s_redirection.selector = gdt_alloc_entry();
initialize_redirection();
s_colonel_process = Process::create_kernel_process(hlt_loop, "colonel");
current = nullptr;
redo_colonel_process_tss();
load_task_register(s_colonel_process->selector());
load_task_register(s_redirection.selector);
}