101 lines
3.1 KiB
C
101 lines
3.1 KiB
C
/*
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* Copyright (c) 2010, Stefan Lankes, RWTH Aachen University
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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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 structure definitions
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*
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* This file contains the task_t structure definition
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* and task state define constants
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*/
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#ifndef __ASM_TASKS_H__
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#define __ASM_TASKS_H__
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#include <eduos/stddef.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* @brief Switch to current task
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*
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* @param stack Pointer to the old stack pointer
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*/
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void switch_context(size_t** stack);
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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, entry_point_t ep, void* arg);
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/** @brief Copy kernel stack pointer to TSS */
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void set_kernel_stack(size_t stack);
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/** @brief Register a task's TSS at GDT
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*
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* @return
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* - 0 on success
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*/
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static inline int register_task(void)
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{
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uint16_t sel = 5 << 3;
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asm volatile ("ltr %%ax" : : "a"(sel));
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return 0;
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}
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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" ::: "cc");
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return 0;
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}
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#ifdef __cplusplus
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}
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#endif
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#endif
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