irq: suppress warning on !CONFIG_KERN_PREEMPT

[bertos.git] / bertos / kern / preempt.c

diff --git a/bertos/kern/preempt.c b/bertos/kern/preempt.c
index 7ecd481d0cdf57c6d4c3679fc4ccfa43f5cc794e..f285d43f5a53c3e3932f3d1d5edca9be072a26d2 100644 (file)
--- a/bertos/kern/preempt.c
+++ b/bertos/kern/preempt.c
@@ -41,73 +41,57 @@
 #include <kern/irq.h>
 #include <kern/monitor.h>
 #include <cpu/frame.h> // CPU_IDLE
+#include <cpu/irq.h>   // IRQ_DISABLE()...
 #include <drv/timer.h>
 #include <cfg/module.h>
 
 
+int preempt_forbid_cnt;
 
-Timer preempt_timer;
+static Timer preempt_timer;
 
-/**
- * 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;
-}
+// fwd decl from idle.c
+void idle_init(void);
 
 
 void proc_preempt(void)
 {
        IRQ_DISABLE;
 
+       ASSERT(preempt_forbid_cnt == 0);
        LIST_ASSERT_VALID(&ProcReadyList);
        CurrentProcess = (struct Process *)list_remHead(&ProcReadyList);
-       LIST_ASSERT_VALID(&ProcReadyList);
        ASSERT2(CurrentProcess, "no idle proc?");
 
        IRQ_ENABLE;
 
-       TRACEMSG("new proc: %p:%s", CurrentProcess, CurrentProcess ? CurrentProcess->monitor.name : "---");
-       monitor_report();
+       TRACEMSG("launching %p:%s", CurrentProcess, proc_currentName());
 }
 
 void proc_preempt_timer(UNUSED_ARG(void *, param))
 {
-       IRQ_DISABLE;
-/*
-       if (!CurrentProcess->forbid_cnt)
+       if (!preempt_forbid_cnt)
        {
-               TRACEMSG("preempting %p:%s", CurrentProcess, CurrentProcess->monitor.name);
-               LIST_ASSERT_VALID(&ProcReadyList);
+               IRQ_DISABLE;
+
+               #if CONFIG_KERN_PRI
+                       Process *rival = (Process *)LIST_HEAD(&ProcReadyList);
+                       if (rival && rival->link.pri >= CurrentProcess->link.pri)
+                       {
+               #endif
+
+               TRACEMSG("preempting %p:%s", CurrentProcess, proc_currentName());
+#if 0
                SCHED_ENQUEUE(CurrentProcess);
                proc_preempt();
+#endif
+               #if CONFIG_KERN_PRI
+                       }
+               #endif
+
+               IRQ_ENABLE;
        }
-*/
-       IRQ_ENABLE;
 
        timer_setDelay(&preempt_timer, CONFIG_KERN_QUANTUM);
        timer_add(&preempt_timer);
@@ -115,7 +99,13 @@ void proc_preempt_timer(UNUSED_ARG(void *, param))
 
 void proc_schedule(void)
 {
-       TRACE;
+       ATOMIC(LIST_ASSERT_VALID(&ProcReadyList));
+       TRACEMSG("%p:%s", CurrentProcess, proc_currentName());
+       ATOMIC(LIST_ASSERT_VALID(&ProcReadyList));
+
+       /* Sleeping with IRQs disabled or preemption forbidden is illegal */
+       ASSERT_IRQ_ENABLED();
+       ASSERT(preempt_forbid_cnt == 0);
 
        // Will invoke proc_preempt() in interrupt context
        kill(0, SIGUSR1);
@@ -123,14 +113,13 @@ void proc_schedule(void)
 
 void proc_yield(void)
 {
-       TRACE;
+       TRACEMSG("%p:%s", CurrentProcess, proc_currentName());
 
-       ASSERT_IRQ_ENABLED();
        IRQ_DISABLE;
        SCHED_ENQUEUE(CurrentProcess);
-       LIST_ASSERT_VALID(&ProcReadyList);
-       proc_schedule();
        IRQ_ENABLE;
+
+       proc_schedule();
 }
 
 void proc_entry(void (*user_entry)(void))
@@ -139,29 +128,6 @@ void proc_entry(void (*user_entry)(void))
        proc_exit();
 }
 
-
-static cpustack_t idle_stack[CONFIG_PROC_DEFSTACKSIZE / sizeof(cpustack_t)];
-
-/*
- * The idle process
- *
- * This process never dies and never sleeps.  It's also quite apathic
- * and a bit antisocial.
- *
- * Having an idle process costs some stack space, but simplifies the
- * interrupt-driven preemption logic because there is always a user
- * context to which we can return.
- */
-static NORETURN void idle(void)
-{
-       for (;;)
-       {
-               TRACE;
-               monitor_report();
-               proc_yield(); // FIXME: CPU_IDLE
-       }
-}
-
 void preempt_init(void)
 {
        MOD_CHECK(irq);
@@ -173,5 +139,5 @@ void preempt_init(void)
        timer_setDelay(&preempt_timer, CONFIG_KERN_QUANTUM);
        timer_add(&preempt_timer);
 
-       proc_new(idle, NULL, sizeof(idle_stack), idle_stack);
+       idle_init();
 }