+++ /dev/null
-/*!
- * \file
- * <!--
- * 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.
- * Context switching is only done cooperatively.
- *
- * \version $Id$
- *
- * \author Bernardo Innocenti <bernie@develer.com>
- * \author Stefano Fedrigo <aleph@develer.com>
- */
-
-/*#*
- *#* $Log$
- *#* Revision 1.24 2005/01/08 09:20:54 bernie
- *#* Remove unused variable.
- *#*
- *#* Revision 1.23 2004/12/13 12:07:06 bernie
- *#* DISABLE_IRQSAVE/ENABLE_IRQRESTORE: Convert to IRQ_SAVE_DISABLE/IRQ_RESTORE.
- *#*
- *#* Revision 1.22 2004/12/13 11:51:08 bernie
- *#* DISABLE_INTS/ENABLE_INTS: Convert to IRQ_DISABLE/IRQ_ENABLE.
- *#*
- *#* Revision 1.21 2004/11/28 23:20:25 bernie
- *#* Remove obsolete INITLIST macro.
- *#*
- *#* Revision 1.20 2004/11/16 22:37:14 bernie
- *#* Replace IPTR with iptr_t.
- *#*
- *#* Revision 1.19 2004/10/19 11:47:39 bernie
- *#* Kill warnings when !CONFIG_PROC_MONITOR.
- *#*
- *#* Revision 1.18 2004/10/19 08:54:43 bernie
- *#* Initialize forbid_cnt; Formatting/comments fixes.
- *#*
- *#* Revision 1.17 2004/10/19 08:47:13 bernie
- *#* proc_rename(), proc_forbid(), proc_permit(): New functions.
- *#*
- *#* Revision 1.16 2004/10/03 20:39:28 bernie
- *#* Import changes from sc/firmware.
- *#*
- *#* Revision 1.15 2004/09/20 03:29:39 bernie
- *#* C++ fixes.
- *#*
- *#* Revision 1.14 2004/09/14 21:06:44 bernie
- *#* Use debug.h instead of kdebug.h.
- *#*
- *#* Revision 1.13 2004/08/29 21:58:53 bernie
- *#* Include macros.h explicityl.
- *#*
- *#* Revision 1.11 2004/08/24 16:09:08 bernie
- *#* Add missing header.
- *#*
- *#* Revision 1.10 2004/08/24 16:07:01 bernie
- *#* Use kputs()/kputchar() when possible.
- *#*
- *#* Revision 1.9 2004/08/24 14:26:57 bernie
- *#* monitor_debug_stacks(): Conditionally compile on CONFIG_KERN_MONITOR.
- *#*
- *#* Revision 1.8 2004/08/14 19:37:57 rasky
- *#* Merge da SC: macros.h, pool.h, BIT_CHANGE, nome dei processi, etc.
- *#*
- *#* Revision 1.7 2004/08/02 20:20:29 aleph
- *#* Merge from project_ks
- *#*
- *#* Revision 1.6 2004/07/30 14:24:16 rasky
- *#* Task switching con salvataggio perfetto stato di interrupt (SR)
- *#* Kernel monitor per dump informazioni su stack dei processi
- *#*
- *#* 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 "proc_p.h"
-#include "proc.h"
-#include "cpu.h"
-#include "event.h"
-#include "hw.h"
-#include <debug.h>
-#include <arch_config.h> /* ARCH_EMUL */
-#include <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
-}
-
-
-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);
-}
-
-
-/*!
- * 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 *)StackFreeList.head;
- REMOVE((Node *)stack_base);
- stacksize = DEF_STACKSIZE;
-#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);
-
- /* 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, CONFIG_KERN_STACKFILLCODE, stacksize / sizeof(cpustack_t));
-#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)
-{
- /* This function must not have any "auto" variables, otherwise
- * the compiler might put them on the stack of the process
- * being switched out.
- */
- static struct Process *old_process;
- static cpuflags_t flags;
-
- /* Remember old process to save its context later */
- old_process = CurrentProcess;
-
- /* Poll on the ready queue for the first ready process */
- IRQ_SAVE_DISABLE(flags);
- while (!(CurrentProcess = (struct Process *)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;
- SCHEDULER_IDLE;
- IRQ_DISABLE;
- }
- IRQ_RESTORE(flags);
-
- /*
- * Optimization: don't switch contexts when the active
- * process has not changed.
- */
- if (CurrentProcess != old_process)
- {
- static 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_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)
-#error This is wrong
- /* Reinsert process stack in free list */
- ADDHEAD(&StackFreeList, (Node *)(CurrentProcess->stack
- - (DEF_STACKSIZE / 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 */
-
-#if CONFIG_KERN_MONITOR
- monitor_remove(CurrentProcess);
-#endif
-
- CurrentProcess = NULL;
- proc_schedule();
- /* not reached */
-}
-
-
-/*!
- * Co-operative context switch
- */
-void proc_switch(void)
-{
- /* Just like proc_schedule, this function must not have auto variables. */
- static 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 */
-
-
-#if 0 /* Simple testcase for the scheduler */
-
-#include <drv/timer.h>
-
-/*!
- * Proc scheduling test subthread 1
- */
-static void NORETURN proc_test_thread1(void)
-{
- for (;;)
- {
- kputs(">task 1\n");
- timer_delay(50);
- proc_switch();
- }
-}
-
-/*!
- * Proc scheduling test subthread 2
- */
-static void NORETURN proc_test_thread2(void)
-{
- for (;;)
- {
- kputs(">task 2\n");
- timer_delay(75);
- proc_switch();
- }
-}
-
-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
- */
-void NORETURN proc_test(void)
-{
- proc_new(proc_test_thread1, NULL, sizeof(proc_test_stack1), proc_test_stack1);
- proc_new(proc_test_thread2, NULL, 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);
-}
-#endif
projects / bertos.git / blobdiff