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8c32471e0d
Previously CPU statue was passed on the stack, but the compiler is allowed to clobber values passed to it on the stack in the SysV x86 ABI. So now leave the state on the stack but pass a pointer to it into the ISR functions.
87 lines
2.4 KiB
C++
87 lines
2.4 KiB
C++
#pragma once
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/// \file scheduler.h
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/// The task scheduler and related definitions
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#include <stdint.h>
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#include "kutil/slab_allocator.h"
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#include "process.h"
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class lapic;
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struct page_table;
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struct cpu_state;
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extern "C" uintptr_t isr_handler(uintptr_t, cpu_state*);
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/// The task scheduler
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class scheduler
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{
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public:
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static const uint8_t num_priorities = 8;
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static const uint8_t default_priority = num_priorities / 2;
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/// How long the timer quantum is
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static const uint64_t quantum_micros = 100000;
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/// How many quantums a process gets before being rescheduled
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static const uint16_t process_quanta = 10;
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/// Constructor.
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/// \arg apic Pointer to the local APIC object
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scheduler(lapic *apic);
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/// Create a new process from a program image in memory.
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/// \arg name Name of the program image
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/// \arg data Pointer to the image data
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/// \arg size Size of the program image, in bytes
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void create_process(const char *name, const void *data, size_t size);
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/// Start the scheduler working. This may involve starting
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/// timer interrupts or other preemption methods.
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void start();
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/// Run the scheduler, possibly switching to a new task
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/// \arg rsp0 The stack pointer of the current interrupt handler
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/// \returns The stack pointer to switch to
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uintptr_t schedule(uintptr_t rsp0);
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/// Get the current process.
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/// \returns A pointer to the current process' process struct
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inline process * current() { return m_current; }
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/// Look up a process by its PID
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/// \arg pid The requested PID
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/// \returns The process matching that PID, or nullptr
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process_node * get_process_by_id(uint32_t pid);
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/// Get a reference to the system scheduler
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/// \returns A reference to the global system scheduler
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static scheduler & get() { return s_instance; }
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private:
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friend uintptr_t syscall_dispatch(uintptr_t, cpu_state &);
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friend uintptr_t isr_handler(uintptr_t, cpu_state*);
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/// Handle a timer tick
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/// \arg rsp0 The stack pointer of the current interrupt handler
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/// \returns The stack pointer to switch to
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uintptr_t tick(uintptr_t rsp0);
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void prune(uint64_t now);
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lapic *m_apic;
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uint32_t m_next_pid;
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uint32_t m_tick_count;
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using process_slab = kutil::slab_allocator<process>;
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process_slab m_process_allocator;
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process_node *m_current;
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process_list m_runlists[num_priorities];
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process_list m_blocked;
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process_list m_exited;
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static scheduler s_instance;
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};
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