+++ /dev/null
-/**
- * \file
- * <!--
- * This file is part of BeRTOS.
- *
- * Bertos is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
- *
- * As a special exception, you may use this file as part of a free software
- * library without restriction. Specifically, if other files instantiate
- * templates or use macros or inline functions from this file, or you compile
- * this file and link it with other files to produce an executable, this
- * file does not by itself cause the resulting executable to be covered by
- * the GNU General Public License. This exception does not however
- * invalidate any other reasons why the executable file might be covered by
- * the GNU General Public License.
- *
- * Copyright 2001,2004 Develer S.r.l. (http://www.develer.com/)
- * Copyright 1999,2000,2001 Bernardo Innocenti <bernie@develer.com>
- *
- * -->
- *
- * \brief Simple realtime multitasking scheduler.
- * Context switching is only done cooperatively.
- *
- * \version $Id$
- *
- * \author Bernardo Innocenti <bernie@develer.com>
- * \author Stefano Fedrigo <aleph@develer.com>
- */
-
-
-#include "proc_p.h"
-#include "proc.h"
-//#include "hw.h"
-#include <mware/event.h>
-#include <cpu/irq.h>
-#include <cpu/types.h>
-#include <cpu/attr.h>
-#include <cfg/debug.h>
-#include <cfg/module.h>
-#include <cfg/arch_config.h> /* ARCH_EMUL */
-#include <cfg/macros.h> /* ABS() */
-
-#include <string.h> /* memset() */
-
-/**
- * CPU dependent context switching routines.
- *
- * \note This function *MUST* preserve also the status of the interrupts.
- */
-EXTERN_C void asm_switch_context(cpustack_t **new_sp, cpustack_t **save_sp);
-EXTERN_C int asm_switch_version(void);
-
-/*
- * The scheduer tracks ready and waiting processes
- * by enqueuing them in these lists. A pointer to the currently
- * running process is stored in the CurrentProcess pointer.
- *
- * NOTE: these variables are protected by DI/EI locking
- */
-REGISTER Process *CurrentProcess;
-REGISTER List ProcReadyList;
-
-
-#if CONFIG_KERN_PREEMPTIVE
-/*
- * The time sharing scheduler forces a task switch when
- * the current process has consumed its quantum.
- */
-uint16_t Quantum;
-#endif
-
-
-/* In Win32 we must emulate stack on the real process stack */
-#if (ARCH & ARCH_EMUL)
-extern List StackFreeList;
-#endif
-
-/** The main process (the one that executes main()). */
-struct Process MainProcess;
-
-
-static void proc_init_struct(Process *proc)
-{
- /* Avoid warning for unused argument. */
- (void)proc;
-
-#if CONFIG_KERN_SIGNALS
- proc->sig_recv = 0;
-#endif
-
-#if CONFIG_KERN_PREEMPTIVE
- proc->forbid_cnt = 0;
-#endif
-
-#if CONFIG_KERN_HEAP
- proc->flags = 0;
-#endif
-}
-
-MOD_DEFINE(proc);
-
-void proc_init(void)
-{
- LIST_INIT(&ProcReadyList);
-
-#if CONFIG_KERN_MONITOR
- monitor_init();
-#endif
-
- /* We "promote" the current context into a real process. The only thing we have
- * to do is create a PCB and make it current. We don't need to setup the stack
- * pointer because it will be written the first time we switch to another process.
- */
- proc_init_struct(&MainProcess);
- CurrentProcess = &MainProcess;
-
- /* Make sure the assembly routine is up-to-date with us */
- ASSERT(asm_switch_version() == 1);
- MOD_INIT(proc);
-}
-
-
-/**
- * Create a new process, starting at the provided entry point.
- *
- * \return Process structure of new created process
- * if successful, NULL otherwise.
- */
-struct Process *proc_new_with_name(UNUSED(const char *, name), void (*entry)(void), iptr_t data, size_t stacksize, cpustack_t *stack_base)
-{
- Process *proc;
- size_t i;
- size_t proc_size_words = ROUND2(sizeof(Process), sizeof(cpustack_t)) / sizeof(cpustack_t);
-#if CONFIG_KERN_HEAP
- bool free_stack = false;
-#endif
-
-#if (ARCH & ARCH_EMUL)
- /* Ignore stack provided by caller and use the large enough default instead. */
- stack_base = (cpustack_t *)LIST_HEAD(&StackFreeList);
- REMOVE(LIST_HEAD(&StackFreeList));
- stacksize = CONFIG_PROC_DEFSTACKSIZE;
-#elif CONFIG_KERN_HEAP
- /* Did the caller provide a stack for us? */
- if (!stack_base)
- {
- /* Did the caller specify the desired stack size? */
- if (!stacksize)
- stacksize = CONFIG_PROC_DEFSTACKSIZE + sizeof(Process);
-
- /* Allocate stack dinamically */
- if (!(stack_base = heap_alloc(stacksize)))
- return NULL;
-
- free_stack = true;
- }
-#else
- /* Stack must have been provided by the user */
- ASSERT(stack_base);
- ASSERT(stacksize);
-#endif
-
-#if CONFIG_KERN_MONITOR
- /* Fill-in the stack with a special marker to help debugging */
- memset(stack_base, (char)CONFIG_KERN_STACKFILLCODE, stacksize);
-#endif
-
- /* Initialize the process control block */
- if (CPU_STACK_GROWS_UPWARD)
- {
- proc = (Process*)stack_base;
- proc->stack = stack_base + proc_size_words;
- if (CPU_SP_ON_EMPTY_SLOT)
- proc->stack++;
- }
- else
- {
- proc = (Process*)(stack_base + stacksize / sizeof(cpustack_t) - proc_size_words);
- proc->stack = (cpustack_t*)proc;
- if (CPU_SP_ON_EMPTY_SLOT)
- proc->stack--;
- }
-
- proc_init_struct(proc);
- proc->user_data = data;
-
-#if CONFIG_KERN_HEAP
- proc->stack_base = stack_base;
- proc->stack_size = stack_size;
- if (free_stack)
- proc->flags |= PF_FREESTACK;
-#endif
-
- /* Initialize process stack frame */
- CPU_PUSH_CALL_CONTEXT(proc->stack, proc_exit);
- CPU_PUSH_CALL_CONTEXT(proc->stack, entry);
-
- /* Push a clean set of CPU registers for asm_switch_context() */
- for (i = 0; i < CPU_SAVED_REGS_CNT; i++)
- CPU_PUSH_WORD(proc->stack, CPU_REG_INIT_VALUE(i));
-
- /* Add to ready list */
- ATOMIC(SCHED_ENQUEUE(proc));
-
-#if CONFIG_KERN_MONITOR
- monitor_add(proc, name, stack_base, stacksize);
-#endif
-
- return proc;
-}
-
-/** Rename a process */
-void proc_rename(struct Process *proc, const char *name)
-{
-#if CONFIG_KERN_MONITOR
- monitor_rename(proc, name);
-#else
- (void)proc; (void)name;
-#endif
-}
-
-
-/**
- * System scheduler: pass CPU control to the next process in
- * the ready queue.
- *
- * Saving and restoring the context on the stack is done
- * by a CPU-dependent support routine which must usually be
- * written in assembly.
- */
-void proc_schedule(void)
-{
- struct Process *old_process;
- cpuflags_t flags;
-
- /* Remember old process to save its context later */
- old_process = CurrentProcess;
-
-#ifdef IRQ_RUNNING
- /* Scheduling in interrupts is a nono. */
- ASSERT(!IRQ_RUNNING());
-#endif
-
- /* Poll on the ready queue for the first ready process */
- IRQ_SAVE_DISABLE(flags);
- while (!(CurrentProcess = (struct Process *)list_remHead(&ProcReadyList)))
- {
- /*
- * Make sure we physically reenable interrupts here, no matter what
- * the current task status is. This is important because if we
- * are idle-spinning, we must allow interrupts, otherwise no
- * process will ever wake up.
- *
- * \todo If there was a way to write sig_wait() so that it does not
- * disable interrupts while waiting, there would not be any
- * reason to do this.
- */
- IRQ_ENABLE;
- CPU_IDLE;
- IRQ_DISABLE;
- }
- IRQ_RESTORE(flags);
-
- /*
- * Optimization: don't switch contexts when the active
- * process has not changed.
- */
- if (CurrentProcess != old_process)
- {
- cpustack_t *dummy;
-
-#if CONFIG_KERN_PREEMPTIVE
- /* Reset quantum for this process */
- Quantum = CONFIG_KERN_QUANTUM;
-#endif
-
- /* Save context of old process and switch to new process. If there is no
- * old process, we save the old stack pointer into a dummy variable that
- * we ignore. In fact, this happens only when the old process has just
- * exited.
- * TODO: Instead of physically clearing the process at exit time, a zombie
- * list should be created.
- */
- asm_switch_context(&CurrentProcess->stack, old_process ? &old_process->stack : &dummy);
- }
-
- /* This RET resumes the execution on the new process */
-}
-
-
-/**
- * Terminate the current process
- */
-void proc_exit(void)
-{
-#if CONFIG_KERN_MONITOR
- monitor_remove(CurrentProcess);
-#endif
-
-#if CONFIG_KERN_HEAP
- /*
- * The following code is BROKEN.
- * We are freeing our own stack before entering proc_schedule()
- * BAJO: A correct fix would be to rearrange the scheduler with
- * an additional parameter which frees the old stack/process
- * after a context switch.
- */
- if (CurrentProcess->flags & PF_FREESTACK)
- heap_free(CurrentProcess->stack_base, CurrentProcess->stack_size);
- heap_free(CurrentProcess);
-#endif
-
-#if (ARCH & ARCH_EMUL)
-#warning This is wrong
- /* Reinsert process stack in free list */
- ADDHEAD(&StackFreeList, (Node *)(CurrentProcess->stack
- - (CONFIG_PROC_DEFSTACKSIZE / sizeof(cpustack_t))));
-
- /*
- * NOTE: At this point the first two words of what used
- * to be our stack contain a list node. From now on, we
- * rely on the compiler not reading/writing the stack.
- */
-#endif /* ARCH_EMUL */
-
- CurrentProcess = NULL;
- proc_schedule();
- /* not reached */
-}
-
-
-/**
- * Co-operative context switch
- */
-void proc_switch(void)
-{
- cpuflags_t flags;
-
- IRQ_SAVE_DISABLE(flags);
- SCHED_ENQUEUE(CurrentProcess);
- IRQ_RESTORE(flags);
-
- proc_schedule();
-}
-
-
-/**
- * Get the pointer to the current process
- */
-struct Process *proc_current(void)
-{
- return CurrentProcess;
-}
-
-/**
- * Get the pointer to the user data of the current process
- */
-iptr_t proc_current_user_data(void)
-{
- return CurrentProcess->user_data;
-}
-
-
-#if CONFIG_KERN_PREEMPTIVE
-
-/**
- * Disable preemptive task switching.
- *
- * The scheduler maintains a per-process nesting counter. Task switching is
- * effectively re-enabled only when the number of calls to proc_permit()
- * matches the number of calls to proc_forbid().
- *
- * Calling functions that could sleep while task switching is disabled
- * is dangerous, although supported. Preemptive task switching is
- * resumed while the process is sleeping and disabled again as soon as
- * it wakes up again.
- *
- * \sa proc_permit()
- */
-void proc_forbid(void)
-{
- /* No need to protect against interrupts here. */
- ++CurrentProcess->forbid_cnt;
-}
-
-/**
- * Re-enable preemptive task switching.
- *
- * \sa proc_forbid()
- */
-void proc_permit(void)
-{
- /* No need to protect against interrupts here. */
- --CurrentProcess->forbid_cnt;
-}
-
-#endif /* CONFIG_KERN_PREEMPTIVE */
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