99 lines
2.5 KiB
C
99 lines
2.5 KiB
C
/*
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* Copyright 2010 Stefan Lankes, Chair for Operating Systems,
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* RWTH Aachen University
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* This file is part of MetalSVM.
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*
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*/
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/**
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* @author Stefan Lankes
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* @file arch/x86/include/asm/tasks.h
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* @brief Task-related functions for forking and scheduling
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*
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* This file contains functions needed for task switching, scheduling and task creation.
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*/
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#ifndef __ARCH_TASKS__
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#define __ARCH_TASKS__
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#include <metalsvm/stddef.h>
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#include <metalsvm/tasks_types.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/** @brief Fork a task from current task
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*
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* @param task Pointer to the task structure to fork to
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* @return
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* - 0 on success
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* - -EINVAL (-22) on failure
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*/
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int arch_fork(task_t* task);
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/** @brieff Switch to new task
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* @param id Task Id
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*/
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void switch_task(uint32_t id);
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/** @brief Setup a default frame for a new task
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*
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* @param task Pointer to the task structure
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* @param ep The entry point for code execution
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* @param arg Arguments list pointer for the task's stack
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* @return
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* - 0 on success
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* - -EINVAL (-22) on failure
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*/
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int create_default_frame(task_t* task, internal_entry_point_t ep, void* arg);
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/** @brief Register a task's TSS at GDT
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*
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* @param task Pointer to task structure
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* @return
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* - 0 on success
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* - -EINVAL (-22) on failure
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*/
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int register_task(task_t* task);
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/** @brief Jump back to user code
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*
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* This function runs the user code after stopping it just as if
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* it was a return from a procedure.
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*
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* @return 0 in any case
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*/
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static inline int jump_to_user_code(uint32_t ep, uint32_t stack)
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{
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asm volatile ("mov %0, %%ds; mov %0, %%fs; mov %0, %%gs; mov %0, %%es" :: "r"(0x23));
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asm volatile ("push $0x23; push %0; push $0x1B; push %1" :: "r"(stack), "r"(ep));
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asm volatile ("lret");
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return 0;
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}
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/** @brief determines the stack of a specific task
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*
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* @return start address of a specific task
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*/
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size_t get_stack(uint32_t id);
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#ifdef __cplusplus
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}
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#endif
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#endif
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