64 lines
2.1 KiB
C++
64 lines
2.1 KiB
C++
/*
|
|
* Scheduler.hpp
|
|
* Preemptive process scheduler with user-mode support
|
|
* Copyright (c) 2025 Daniel Hammer
|
|
*/
|
|
|
|
#pragma once
|
|
#include <cstdint>
|
|
|
|
namespace Sched {
|
|
|
|
static constexpr int MaxProcesses = 16;
|
|
static constexpr uint64_t StackPages = 4; // 16 KiB kernel stack per process
|
|
static constexpr uint64_t StackSize = StackPages * 0x1000;
|
|
static constexpr uint64_t UserStackPages = 4; // 16 KiB user stack
|
|
static constexpr uint64_t UserStackSize = UserStackPages * 0x1000;
|
|
static constexpr uint64_t UserStackTop = 0x7FFFFFF000ULL; // User stack top VA
|
|
static constexpr uint64_t UserHeapBase = 0x40000000ULL; // User heap start VA
|
|
static constexpr uint64_t ExitStubAddr = 0x3FF000ULL; // User-space exit stub page
|
|
static constexpr uint64_t TimeSliceMs = 10; // 10 ms time slice
|
|
|
|
enum class ProcessState {
|
|
Free,
|
|
Ready,
|
|
Running,
|
|
Terminated
|
|
};
|
|
|
|
struct Process {
|
|
int pid;
|
|
ProcessState state;
|
|
const char* name;
|
|
uint64_t savedRsp;
|
|
uint64_t stackBase; // Bottom of allocated kernel stack (lowest address)
|
|
uint64_t entryPoint;
|
|
uint64_t sliceRemaining; // Ticks left in current time slice
|
|
uint64_t pml4Phys; // Physical address of per-process PML4
|
|
uint64_t kernelStackTop; // Top of kernel stack (for TSS RSP0 / SYSCALL)
|
|
uint64_t userStackTop; // User-space stack top
|
|
uint64_t heapNext; // Simple bump allocator for user heap
|
|
char args[256]; // Command-line arguments (set by parent via Spawn)
|
|
};
|
|
|
|
void Initialize();
|
|
int Spawn(const char* vfsPath, const char* args = nullptr);
|
|
void Schedule();
|
|
|
|
// Called from the APIC timer handler on every tick.
|
|
void Tick();
|
|
|
|
// Get the PID of the currently running process (-1 if idle)
|
|
int GetCurrentPid();
|
|
|
|
// Get a pointer to the currently running process (nullptr if idle)
|
|
Process* GetCurrentProcessPtr();
|
|
|
|
// Called by terminated processes to mark themselves done
|
|
void ExitProcess();
|
|
|
|
// Check if a process is still alive (Ready or Running)
|
|
bool IsAlive(int pid);
|
|
|
|
}
|