
- create the variable current_task on each core git-svn-id: http://svn.lfbs.rwth-aachen.de/svn/scc/trunk/MetalSVM@159 315a16e6-25f9-4109-90ae-ca3045a26c18
310 lines
7.2 KiB
C
310 lines
7.2 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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#include <metalsvm/stdio.h>
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#include <metalsvm/stdlib.h>
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#include <metalsvm/string.h>
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#include <metalsvm/errno.h>
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#include <metalsvm/mmu.h>
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#include <metalsvm/tasks.h>
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#include <metalsvm/processor.h>
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#include <metalsvm/spinlock.h>
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#include <metalsvm/mailbox.h>
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#include <metalsvm/syscall.h>
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DEFINE_PER_CORE(task_t*, current_task, NULL);
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static task_t task_table[MAX_TASKS] = {[0 ... MAX_TASKS-1] = {0, 0, NULL, 0, ATOMIC_INIT(0)}};
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static spinlock_t table_lock = SPINLOCK_INIT;
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/*
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* helper function for the assembly code to determine the current task
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*/
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task_t* get_current_task(void)
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{
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return per_core(current_task);
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}
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int multitasking_init(void) {
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unsigned int i;
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for(i=0; i<MAX_TASKS; i++) {
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if (task_table[i].status == TASK_INVALID) {
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task_table[i].id = i;
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task_table[i].status = TASK_RUNNING;
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memset(task_table[i].mbox, 0x00, sizeof(mailbox_int32_t*)*MAX_TASKS);
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per_core(current_task) = task_table+i;
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register_task(per_core(current_task));
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return 0;
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}
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}
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return -ENOMEM;
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}
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static void wakeup_blocked_tasks(int result)
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{
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unsigned int i;
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spinlock_lock_irqsave(&table_lock);
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/* wake up blocked tasks */
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for(i=0; i<MAX_TASKS; i++) {
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if (per_core(current_task)->mbox[i]) {
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mailbox_int32_post(per_core(current_task)->mbox[i], result);
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per_core(current_task)->mbox[i] = NULL;
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}
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}
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spinlock_unlock_irqsave(&table_lock);
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}
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static void NORETURN do_exit(int arg) {
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kprintf("Terminate task: %u, return value %d\n", per_core(current_task)->id, arg);
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wakeup_blocked_tasks(arg);
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if (per_core(current_task)->ustack)
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kfree(per_core(current_task)->ustack, per_core(current_task)->stack_size);
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if (atomic_int32_read(&per_core(current_task)->mem_usage))
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kprintf("Memory leak! Task %d did not release %d bytes\n", per_core(current_task)->id, atomic_int32_read(&per_core(current_task)->mem_usage));
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per_core(current_task)->status = TASK_FINISHED;
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reschedule();
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kputs("Kernel panic: scheduler found no valid task\n");
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while(1) {
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NOP8;
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}
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}
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void NORETURN leave_kernel_task(void) {
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int result;
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result = get_return_value();
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do_exit(result);
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}
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void NORETURN leave_user_task(void) {
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int result;
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result = get_return_value();
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SYSCALL1(__NR_exit, result);
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kprintf("Kernel panic! Task %d comes back from syscall \"exit\"\n", per_core(current_task)->id);
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while(1) {
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NOP8;
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}
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}
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void NORETURN sys_exit(int arg)
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{
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do_exit(arg);
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}
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void NORETURN abort(void) {
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do_exit(-1);
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}
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static int create_task(tid_t* id, entry_point_t ep, void* arg, size_t stack_size, int user)
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{
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int ret = -ENOMEM;
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unsigned int i;
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if (BUILTIN_EXPECT(!ep, 0))
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return -EINVAL;
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if (user && !stack_size)
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stack_size = DEFAULT_STACK_SIZE;
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spinlock_lock_irqsave(&table_lock);
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for(i=0; i<MAX_TASKS; i++) {
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if (task_table[i].status == TASK_INVALID) {
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task_table[i].id = i;
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task_table[i].status = TASK_READY;
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if (user) {
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task_table[i].ustack = create_stack(task_table+i, stack_size);
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if (!task_table[i].ustack)
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break;
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task_table[i].stack_size = stack_size;
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} else {
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task_table[i].ustack = NULL;
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task_table[i].stack_size = 0;
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}
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atomic_int32_set(&task_table[i].mem_usage, 0);
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memset(task_table[i].mbox, 0x00, sizeof(mailbox_int32_t*)*MAX_TASKS);
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if (id)
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*id = i;
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ret = create_default_frame(task_table+i, ep, arg, user);
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break;
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}
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}
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spinlock_unlock_irqsave(&table_lock);
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return ret;
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}
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int create_kernel_task(tid_t* id, entry_point_t ep, void* arg)
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{
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return create_task(id, ep, arg, 0, 0);
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}
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int create_user_task(tid_t* id, entry_point_t ep, void* arg, size_t stack_size)
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{
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return create_task(id, ep, arg, stack_size, 1);
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}
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int join_task(tid_t id, int* result)
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{
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int32_t tmp;
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mailbox_int32_t mbox;
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mailbox_int32_init(&mbox);
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spinlock_lock_irqsave(&table_lock);
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/*
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* idle tasks are not allowed to wait for another task
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* they should always run...
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*/
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if (BUILTIN_EXPECT(per_core(current_task)->status == TASK_IDLE, 0))
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goto join_out;
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/* a task is not able to wait for itself */
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if (BUILTIN_EXPECT(per_core(current_task)->id == id, 0))
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goto join_out;
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/* invalid id */
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if (BUILTIN_EXPECT(id >= MAX_TASKS, 0))
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goto join_out;
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/* task already finished */
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if (BUILTIN_EXPECT(task_table[id].status == TASK_INVALID, 0))
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goto join_out;
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/* task already finished */
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if (BUILTIN_EXPECT(task_table[id].status == TASK_FINISHED, 0))
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goto join_out;
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task_table[id].mbox[per_core(current_task)->id] = &mbox;
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spinlock_unlock_irqsave(&table_lock);
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mailbox_int32_fetch(&mbox, &tmp);
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if (result)
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*result = tmp;
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mailbox_int32_destroy(&mbox);
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return 0;
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join_out:
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spinlock_unlock_irqsave(&table_lock);
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mailbox_int32_destroy(&mbox);
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return -EINVAL;
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}
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int wakeup_task(tid_t id)
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{
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int ret = -EINVAL;
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int need_lock = !spinlock_has_lock(&table_lock);
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/* avoid nested locking */
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if (need_lock)
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spinlock_lock_irqsave(&table_lock);
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if (task_table[id].status != TASK_BLOCKED) {
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kprintf("Task %d is not blocked!\n", id);
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} else {
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task_table[id].status = TASK_READY;
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ret = 0;
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}
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if (need_lock)
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spinlock_unlock_irqsave(&table_lock);
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return ret;
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}
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int block_task(tid_t id)
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{
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int ret = -EINVAL;
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int need_lock = !spinlock_has_lock(&table_lock);
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/* avoid nested locking */
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if (need_lock)
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spinlock_lock_irqsave(&table_lock);
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if ((task_table[id].status == TASK_RUNNING) || (task_table[id].status == TASK_READY)) {
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task_table[id].status = TASK_BLOCKED;
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ret = 0;
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} else kprintf("Unable to block task %d!\n", id);
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if (need_lock)
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spinlock_unlock_irqsave(&table_lock);
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return ret;
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}
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void scheduler(void)
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{
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unsigned int i;
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unsigned int new_id;
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spinlock_lock(&table_lock);
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/* signalize that this task could be reuse */
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if (per_core(current_task)->status == TASK_FINISHED)
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per_core(current_task)->status = TASK_INVALID;
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for(i=1; i<MAX_TASKS; i++) {
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new_id = (per_core(current_task)->id + i) % MAX_TASKS;
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if (task_table[new_id].status == TASK_READY) {
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if (per_core(current_task)->status == TASK_RUNNING)
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per_core(current_task)->status = TASK_READY;
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task_table[new_id].status = TASK_RUNNING;
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per_core(current_task) = task_table+new_id;
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goto get_task_out;
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}
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}
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if ((per_core(current_task)->status == TASK_RUNNING) || (per_core(current_task)->status == TASK_IDLE))
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goto get_task_out;
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/*
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* we switch to the idle task, if the current task terminates
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* and no other is ready
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*/
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for(i=0; i<MAX_TASKS; i++) {
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if (task_table[i].status == TASK_IDLE) {
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per_core(current_task) = task_table+i;
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goto get_task_out;
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}
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}
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get_task_out:
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spinlock_unlock(&table_lock);
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}
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