From e0449c5adc89eec9f378cb40a56762bf314a80ea Mon Sep 17 00:00:00 2001
From: Miguel <m.i@gmx.at>
Date: Sat, 15 Sep 2018 23:46:04 +0200
Subject: scheduler / sleep process

---
 kernel/scheduler.c | 75 ++++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 61 insertions(+), 14 deletions(-)

(limited to 'kernel/scheduler.c')

diff --git a/kernel/scheduler.c b/kernel/scheduler.c
index ad6b370..b5d1b34 100644
--- a/kernel/scheduler.c
+++ b/kernel/scheduler.c
@@ -73,25 +73,36 @@ volatile void scheduler_init(uint32_t cpu, void *dir)
     task_list[cpu][0].pid=nextPID();
     task_list[cpu][0].active=true;
     task_list[cpu][0].syscall=false;
-    task_list[cpu][0].thread=false;
+    task_list[cpu][1].thread=false;
     task_list[cpu][0].vmem=dir;
     task_list[cpu][0].esp = VMEM_CPU_STACK_TOP-0x200;
     task_list[cpu][0].esp0 = 0; // esp0 not needed by kernel space tasks
 
-    task_pusha(task_list[cpu][0].esp);
-
-    // this is our main kernel task at slot 0 (per cpu)
+    // this will go to userspace 
     task_list[cpu][1].parent=0;
     task_list[cpu][1].pid=nextPID();
     task_list[cpu][1].active=true;
-    task_list[cpu][0].thread=false;
+    task_list[cpu][1].thread=false;
     task_list[cpu][1].syscall=false;
     task_list[cpu][1].vmem=dir;
     task_list[cpu][1].esp = kballoc(4)+4*4096-0x200; // 4 pages stack
     task_list[cpu][1].esp0 =kballoc(4)+4*4096;  // esp0 not needed by kernel space tasks
 
+
+    // sleeper
+    task_list[cpu][2].parent=0;
+    task_list[cpu][2].pid=nextPID();
+    task_list[cpu][2].active=true;
+    task_list[cpu][2].thread=false;
+    task_list[cpu][2].syscall=false;
+    task_list[cpu][2].vmem=dir;
+    task_list[cpu][2].esp = kballoc(4)+4*4096-0x200; // 4 pages stack
+    task_list[cpu][2].esp0 =kballoc(4)+4*4096;  // esp0 not needed by kernel space tasks
+
+    // stacks
     task_pusha(task_list[cpu][0].esp);
     task_pusha(task_list[cpu][1].esp);
+    task_pusha(task_list[cpu][2].esp);
 }
 
 //
@@ -104,7 +115,7 @@ volatile void scheduler_init(uint32_t cpu, void *dir)
 //
 // we need to return a NEW stack pointer where popa will get the registers the new task requires
 //
-volatile uint32_t scheduler_run(uint32_t oldesp,uint32_t force_pid)
+volatile uint32_t scheduler_run(uint32_t oldesp)
 {
     uint32_t cpu=smp_get(SMP_APIC_ID);
     uint32_t init=smp_get(SMP_SCHEDULER_INIT);
@@ -117,6 +128,7 @@ volatile uint32_t scheduler_run(uint32_t oldesp,uint32_t force_pid)
     for(int i=0;i<MAX_TASKS;i++)
     {
 	int idx=(current_task[cpu]+1+i)%MAX_TASKS; // schedule round robin style
+	if(idx==2)continue;// skip sleeper here
 
 	if(task_list[cpu][idx].active && !task_list[cpu][idx].syscall) // find active non-blocked task
 	{
@@ -129,7 +141,13 @@ volatile uint32_t scheduler_run(uint32_t oldesp,uint32_t force_pid)
 	}
     }
 
-    kpanic("nothing to schedule!");
+    // force the sleeper task
+	current_task[cpu]=2;
+	install_tss(cpu,task_list[cpu][2].esp0);
+	x86_set_page_directory(task_list[cpu][2].vmem);
+	return task_list[cpu][2].esp;
+
+//    kpanic("nothing to schedule!");
 }
 
 
@@ -146,8 +164,13 @@ void scheduler_func()
         task_syscall_worker();
     }
 
-    if(current_task[cpu]==1)
+    if(current_task[cpu]==2)
+    while(1)
+    {
+	while(1)asm("hlt"); // sleeper task
+    }
 
+    if(current_task[cpu]==1)
     while(1)
     {
 	if(cpu==0)
@@ -205,7 +228,15 @@ volatile int add_task(uint32_t parent_pid,uint32_t vmem, bool thread)
     kpanic("out of task slots!");
 }
 
-void task_wake_all()
+uint32_t scheduler_wake_worker(uint32_t oldesp)
+{
+    uint32_t cpu=smp_get(SMP_APIC_ID);
+    task_list[cpu][0].syscall=false; // wake (syscall misused)
+    scheduler_wake_all();
+    return scheduler_run(oldesp);
+}
+
+void scheduler_wake_all()
 {
 	    uint32_t cpu=smp_get(SMP_APIC_ID);
 		// simple approach, any syscall might unblock any other syscall // TODO: better! TODO: all cpus!
@@ -215,7 +246,6 @@ void task_wake_all()
 		}
 }
 
-
 /**
  * kernel space worker thread
  *
@@ -258,7 +288,7 @@ void task_syscall_worker()
 			    task_list[cpu][i].ebx,
 			    task_list[cpu][i].pid);
 
-		task_wake_all();
+		scheduler_wake_all();
 
 		uint32_t *stack=task_list[cpu][i].esp;
 		stack[12]=0x1; 
@@ -268,9 +298,26 @@ void task_syscall_worker()
 	    }
 	}
 
-	//task_list[cpu][0].wait=true;
-	//if (nowork)__asm__("hlt");
-	__asm__("int $0x81"); // wake scheduler!
+	bool nowork=true;
+
+	x86_cli(); // disable all incoming new work (mouse,kb,timer). software syscalls can not appear since we are here ;)
+	for(int i=0;i<MAX_TASKS;i++) /// ... and check if aaany work is pending.
+	{
+	    if(task_list[cpu][i].active,task_list[cpu][i].try&&task_list[cpu][i].syscall)
+	    {
+		nowork=false;
+		break;
+	    }
+	}
+	if(nowork)
+	{
+	    task_list[cpu][0].syscall=true; // sleep (syscall misused)
+	}
+	x86_sti();
+	if(nowork)
+	{
+	    __asm__("int $0x81"); // wake scheduler!
+	}
     }
 }
 
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