-/*!
+/**
* \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>
- * This file is part of DevLib - See devlib/README for information.
+ *
* -->
*
* \brief Simple realtime multitasking scheduler.
* \author Stefano Fedrigo <aleph@develer.com>
*/
-/*
- * $Log$
- * Revision 1.5 2004/07/14 14:18:09 rasky
- * Merge da SC: Rimosso timer dentro il task, che รจ uno spreco di memoria per troppi task
- *
- * Revision 1.4 2004/07/13 19:21:28 aleph
- * Avoid warning for unused arg when compiled without some CONFIG_KERN_xx options
- *
- * Revision 1.3 2004/06/06 18:37:57 bernie
- * Rename event macros to look like regular functions.
- *
- * Revision 1.2 2004/06/03 11:27:09 bernie
- * Add dual-license information.
- *
- * Revision 1.1 2004/05/23 17:27:00 bernie
- * Import kern/ subdirectory.
- *
- */
-#include "cpu.h"
#include "proc_p.h"
#include "proc.h"
-#include "event.h"
-#include "hw.h"
-#include <drv/kdebug.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 */
-extern void asm_switch_context(cpustack_t **new_sp, cpustack_t **save_sp);
+/**
+ * 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
REGISTER Process *CurrentProcess;
REGISTER List ProcReadyList;
+
#if CONFIG_KERN_PREEMPTIVE
/*
* The time sharing scheduler forces a task switch when
extern List StackFreeList;
#endif
-/* The main process (the one that executes main()) */
+/** The main process (the one that executes main()). */
struct Process MainProcess;
-static void proc_init_struct(Process* proc)
+
+static void proc_init_struct(Process *proc)
{
- /* Avoid warning for unused argument */
+ /* 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)
{
- INITLIST(&ProcReadyList);
+ 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. */
+ * 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.
*/
-Process *proc_new(void (*entry)(void), size_t stacksize, cpustack_t *stack_base)
+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;
#endif
#if (ARCH & ARCH_EMUL)
- /* Ignore stack provided by caller
- * and use the large enough default instead
- */
- stack_base = (cpustack_t *)StackFreeList.head;
- REMOVE((Node *)stack_base);
- stacksize = DEF_STACKSIZE;
+ /* 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_KERN_DEFSTACKSIZE + sizeof(Process);
+ stacksize = CONFIG_PROC_DEFSTACKSIZE + sizeof(Process);
/* Allocate stack dinamically */
if (!(stack_base = heap_alloc(stacksize)))
ASSERT(stacksize);
#endif
-#ifdef _DEBUG
+#if CONFIG_KERN_MONITOR
/* Fill-in the stack with a special marker to help debugging */
memset(stack_base, CONFIG_KERN_STACKFILLCODE, stacksize / sizeof(cpustack_t));
-#endif /* _DEBUG */
+#endif
/* Initialize the process control block */
if (CPU_STACK_GROWS_UPWARD)
}
proc_init_struct(proc);
+ proc->user_data = data;
#if CONFIG_KERN_HEAP
proc->stack_base = stack_base;
CPU_PUSH_WORD(proc->stack, CPU_REG_INIT_VALUE(i));
/* Add to ready list */
- DISABLE_INTS;
- SCHED_ENQUEUE(proc);
- ENABLE_INTS;
+ 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.
*
*/
void proc_schedule(void)
{
- /* This function must not have any "auto" variables, otherwise
- * the compiler might put them on the stack of the process
- * being switched out.
- */
- static Process *old_process;
+ struct Process *old_process;
+ cpuflags_t flags;
/* Remember old process to save its context later */
old_process = CurrentProcess;
- CurrentProcess = NULL;
- /* Poll on the ready queue for the first ready process
- */
- for(;;) /* forever */
+#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)))
{
- /* Do CPU specific idle processing (ARGH, should be moved to the end of the loop!) */
- SCHEDULER_IDLE;
-
- DISABLE_INTS;
- if (!ISLISTEMPTY(&ProcReadyList))
- {
- /* Get process from ready list */
- CurrentProcess = (Process *)ProcReadyList.head;
- REMOVE((Node *)CurrentProcess);
- ENABLE_INTS;
- break;
- }
- ENABLE_INTS;
+ /*
+ * 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.
+ *
+ * During idle-spinning, can occur an interrupt, it may be able to
+ * modify \p ProcReadyList. To ensure that compiler reload this
+ * variable every while cycle we call CPU_MEMORY_BARRIER.
+ * The memory barrier ensure that all variables used in this context
+ * are reloaded.
+ * \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;
+ MEMORY_BARRIER;
+ IRQ_DISABLE;
}
+ IRQ_RESTORE(flags);
- /* Optimization: don't switch contexts when the active
+ /*
+ * Optimization: don't switch contexts when the active
* process has not changed.
*/
if (CurrentProcess != old_process)
{
- static cpustack_t* dummy;
+ cpustack_t *dummy;
#if CONFIG_KERN_PREEMPTIVE
/* Reset quantum for this 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.
+ /*
+ * 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
#endif
#if (ARCH & ARCH_EMUL)
-#error This is wrong
+#warning This is wrong
/* Reinsert process stack in free list */
ADDHEAD(&StackFreeList, (Node *)(CurrentProcess->stack
- - (DEF_STACKSIZE / sizeof(cpustack_t))));
+ - (CONFIG_PROC_DEFSTACKSIZE / sizeof(cpustack_t))));
- /* NOTE: At this point the first two words of what used
+ /*
+ * 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.
*/
}
-/*!
+/**
* Co-operative context switch
*/
void proc_switch(void)
{
- DISABLE_INTS;
+ cpuflags_t flags;
+
+ IRQ_SAVE_DISABLE(flags);
SCHED_ENQUEUE(CurrentProcess);
- ENABLE_INTS;
+ IRQ_RESTORE(flags);
+
proc_schedule();
}
-/*!
+/**
* Get the pointer to the current process
*/
struct Process *proc_current(void)
return CurrentProcess;
}
-
-#if 0 /* Simple testcase for the scheduler */
-
-/*!
- * Proc scheduling test subthread 1
+/**
+ * Get the pointer to the user data of the current process
*/
-static void NORETURN proc_test_thread1(void)
+iptr_t proc_current_user_data(void)
{
- for (;;)
- {
- kputs(">task 1\n");
- timer_delay(50);
- proc_switch();
- }
+ return CurrentProcess->user_data;
}
-/*!
- * Proc scheduling test subthread 2
+
+#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()
*/
-static void NORETURN proc_test_thread2(void)
+void proc_forbid(void)
{
- for (;;)
- {
- kputs(">task 2\n");
- timer_delay(75);
- proc_switch();
- }
+ /* No need to protect against interrupts here. */
+ ++CurrentProcess->forbid_cnt;
}
-static cpustack_t proc_test_stack1[CONFIG_KERN_DEFSTACKSIZE/sizeof(cpustack_t)];
-static cpustack_t proc_test_stack2[CONFIG_KERN_DEFSTACKSIZE/sizeof(cpustack_t)];
-
-/*!
- * Proc scheduling test
+/**
+ * Re-enable preemptive task switching.
+ *
+ * \sa proc_forbid()
*/
-void NORETURN proc_test(void)
+void proc_permit(void)
{
- proc_new(proc_test_thread1, sizeof(proc_test_stack1), proc_test_stack1);
- proc_new(proc_test_thread2, sizeof(proc_test_stack2), proc_test_stack2);
- kputs("Created tasks\n");
-
- kputs("stack1:\n");
- kdump(proc_test_stack1+sizeof(proc_test_stack1)-64, 64);
- kputs("stack2:\n");
- kdump(proc_test_stack2+sizeof(proc_test_stack1)-64, 64);
-
- for (;;)
- {
- kputs(">main task\n");
- timer_delay(93);
- proc_switch();
- }
-
- ASSERT(false);
+ /* No need to protect against interrupts here. */
+ --CurrentProcess->forbid_cnt;
}
-#endif
+
+#endif /* CONFIG_KERN_PREEMPTIVE */
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