104 lines
2.6 KiB
C
104 lines
2.6 KiB
C
/*
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* tasking-multi.c
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*
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* Created on: Sep 8, 2011
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* Author: Tiberiu
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*/
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#include <tasking.h>
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#include <memory-add.h>
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Task* TaskList;
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Task* CurrentTask;
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uint32 NextPid = 1;
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void TaskSwitch ()
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{
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if (!TaskList) return;
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// Save context
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asm volatile ("mov %%esp, %0" : "=r"(CurrentTask->Esp)); // Stack pointer
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asm volatile ("mov %%ebp, %0" : "=r"(CurrentTask->Ebp)); // Base pointer
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CurrentTask->Pd = CurrentDirectory;
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// Next task
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CurrentTask = (!CurrentTask->Next) ? TaskList : CurrentTask->Next ;
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// Switch context
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PagingSwitchDirectory(CurrentTask->Pd);
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asm volatile ("mov %0, %%esp" : : "r"(CurrentTask->Esp)); // Stack pointer
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asm volatile ("mov %0, %%ebp" : : "r"(CurrentTask->Ebp)); // Base pointer
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}
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// Fallback for new tasks
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void TaskEnd ()
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{
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// Find parent of current task
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if (CurrentTask->Pid == TaskList->Pid) TaskList = TaskList->Next;
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else {
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Task* t = TaskList;
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while (t->Next && t->Next->Pid != CurrentTask->Pid) t = t->Next;
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t->Next = CurrentTask->Next;
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}
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// Free allocated space
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kfree((void*)CurrentTask->StackLowerBase);
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kfree(CurrentTask);
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// Wait for next task
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for (;;) ;
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}
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void TaskCreate (void (*func)())
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{
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// Create a new task
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Task* t = kmalloc(sizeof(Task));
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// Set up data
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t->StackLowerBase = (uint32) kmalloc(0x1000); // Allocate some space for new stack
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t->StackUpperBase = t->StackLowerBase + 0x1000;
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t->Next = NULL;
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t->Pd = KernelDirectory;
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t->Pid = NextPid++;
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// Set up stack
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*(uint32 *) (t->StackUpperBase - 0x4) = (uint32) TaskEnd; // Fallback function
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t->Ebp = (uint32) t->StackUpperBase;
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_RegsStack32* regs = (_RegsStack32*) (t->StackUpperBase - 0x4 - sizeof(_RegsStack32));
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asm volatile ("mov %%ss, %0" : "=r" (regs->ss));
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asm volatile ("mov %%cs, %0" : "=r" (regs->cs));
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asm volatile ("pushf; pop %0" : "=r" (regs->eflags));
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asm volatile ("mov %%esi, %0" : "=r" (regs->esi));
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asm volatile ("mov %%edi, %0" : "=r" (regs->edi));
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asm volatile ("mov %%gs, %0" : "=r" (regs->gs));
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asm volatile ("mov %%fs, %0" : "=r" (regs->fs));
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asm volatile ("mov %%es, %0" : "=r" (regs->es));
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asm volatile ("mov %%ds, %0" : "=r" (regs->ds));
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regs->eax = regs->ebx = regs->ecx = regs->edx = 0;
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regs->eip = (uint32)func;
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regs->useresp = t->StackUpperBase-0x4;
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regs->esp = t->StackUpperBase - 40;
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regs->ebp = t->Ebp = t->StackUpperBase;
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// Add the task to the list
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Task* last = TaskList;
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while (last && last->Next) last = last->Next;
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if (last) last->Next = t;
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}
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void TaskInitialize()
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{
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Task* t = kmalloc(sizeof(Task));
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t->Pid = NextPid++;
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t->Pd = KernelDirectory;
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t->Esp = t->Ebp = 0;
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t->Next = NULL;
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TaskList = CurrentTask = t;
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}
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