* 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 Bernie Innocenti <bernie@codewiz.org>
- *
+ * Copyright 2001, 2004 Develer S.r.l. (http://www.develer.com/)
+ * Copyright 1999, 2000, 2001, 2008 Bernie Innocenti <bernie@codewiz.org>
* -->
*
* \brief Simple realtime multitasking scheduler.
* Context switching is only done cooperatively.
*
* \version $Id$
- *
* \author Bernie Innocenti <bernie@codewiz.org>
* \author Stefano Fedrigo <aleph@develer.com>
*/
-
#include "proc_p.h"
#include "proc.h"
#include "cfg/cfg_arch.h" /* ARCH_EMUL */
-#include <cfg/debug.h>
+#include "cfg/cfg_kern.h"
#include <cfg/module.h>
-#include <cfg/macros.h> /* ABS() */
#include <cpu/irq.h>
#include <cpu/types.h>
#include <cpu/attr.h>
-
-#include <mware/event.h>
+#include <cpu/frame.h>
#include <string.h> /* memset() */
-/**
- * CPU dependent context switching routines.
+#if CONFIG_KERN_PREEMPT
+#include "preempt.h"
+#endif
+
+/*
+ * The scheduer tracks ready processes by enqueuing them in the
+ * ready list.
*
- * \note This function *MUST* preserve also the status of the interrupts.
+ * \note Access to the list must occur while interrupts are disabled.
*/
-EXTERN_C void asm_switch_context(cpustack_t **new_sp, cpustack_t **save_sp);
+REGISTER List ProcReadyList;
/*
- * 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.
+ * Holds a pointer to the TCB of the currently running process.
*
- * NOTE: these variables are protected by DI/EI locking
+ * \note User applications should use proc_current() to retrieve this value.
*/
REGISTER Process *CurrentProcess;
-REGISTER List ProcReadyList;
-
-#if CONFIG_KERN_PREEMPTIVE
+#if (ARCH & ARCH_EMUL)
/*
- * The time sharing scheduler forces a task switch when
- * the current process has consumed its quantum.
+ * In hosted environments, we must emulate the stack on the real process stack.
+ *
+ * Access to this list must be protected by PROC_ATOMIC().
*/
-uint16_t Quantum;
-#endif
-
-
-/* In Win32 we must emulate stack on the real process stack */
-#if (ARCH & ARCH_EMUL)
extern List StackFreeList;
#endif
{
LIST_INIT(&ProcReadyList);
-#if CONFIG_KERN_MONITOR
- monitor_init();
-#endif
-
- /* We "promote" the current context into a real process. The only thing we have
+ /*
+ * 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;
+#if CONFIG_KERN_MONITOR
+ monitor_init();
+ monitor_add(CurrentProcess, "main");
+#endif
+
+#if CONFIG_KERN_PREEMPTIVE
+ preempt_init();
+#endif
+
MOD_INIT(proc);
}
#if CONFIG_KERN_HEAP
bool free_stack = false;
#endif
+ TRACEMSG("name=%s", name);
#if (ARCH & ARCH_EMUL)
/* Ignore stack provided by caller and use the large enough default instead. */
- stack_base = (cpustack_t *)list_remHead(&StackFreeList);
+ PROC_ATOMIC(stack_base = (cpustack_t *)list_remHead(&StackFreeList));
stack_size = CONFIG_PROC_DEFSTACKSIZE;
#elif CONFIG_KERN_HEAP
}
#else
/* Stack must have been provided by the user */
- ASSERT(stack_base);
+ ASSERT_VALID_PTR(stack_base);
ASSERT(stack_size);
#endif
#if CONFIG_KERN_MONITOR
/* Fill-in the stack with a special marker to help debugging */
- memset(stack_base, CONFIG_KERN_STACKFILLCODE, stack_size / sizeof(cpustack_t));
+ memset(stack_base, CONFIG_KERN_STACKFILLCODE, stack_size);
#endif
/* Initialize the process control block */
#endif
/* Initialize process stack frame */
- CPU_PUSH_CALL_CONTEXT(proc->stack, proc_exit);
- CPU_PUSH_CALL_CONTEXT(proc->stack, entry);
+ CPU_PUSH_CALL_FRAME(proc->stack, proc_exit);
+ CPU_PUSH_CALL_FRAME(proc->stack, entry);
/* Push a clean set of CPU registers for asm_switch_context() */
for (i = 0; i < CPU_SAVED_REGS_CNT; i++)
/* Add to ready list */
ATOMIC(SCHED_ENQUEUE(proc));
+ ATOMIC(LIST_ASSERT_VALID(&ProcReadyList));
#if CONFIG_KERN_MONITOR
monitor_add(proc, name);
}
-/**
- * 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.
- *
- * During idle-spinning, an interrupt can occur and it may
- * 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
- * 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)
{
+ TRACE;
+
#if CONFIG_KERN_MONITOR
monitor_remove(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))));
+ PROC_ATOMIC(ADDHEAD(&StackFreeList, (Node *)(CurrentProcess->stack
+ - (CONFIG_PROC_DEFSTACKSIZE / sizeof(cpustack_t)))));
/*
* NOTE: At this point the first two words of what used
}
-/**
- * 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
*/
{
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 */
projects / bertos.git / blobdiff