* 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>
- *
+ * Copyright 2001, 2004 Develer S.r.l. (http://www.develer.com/)
+ * Copyright 1999, 2000, 2001, 2008 Bernie Innocenti <bernie@codewiz.org>
* -->
*
* \brief Process scheduler (public interface).
*
* \version $Id$
- *
- * \author Bernardo Innocenti <bernie@develer.com>
+ * \author Bernie Innocenti <bernie@codewiz.org>
*/
#ifndef KERN_PROC_H
#define KERN_PROC_H
-#include <cfg/cfg_kern.h>
+#include "cfg/cfg_kern.h"
#include <cfg/compiler.h>
-#include <cpu/irq.h>
+#if CONFIG_KERN_PREEMPT
+ #include <cfg/debug.h> // ASSERT()
+#endif
+
+#include <cpu/types.h> // cpustack_t
-/* Fwd decl */
+/*
+ * Forward declaration. The definition of struct Process is private to the
+ * scheduler and hidden in proc_p.h.
+ */
struct Process;
/* Task scheduling services */
#endif
void proc_exit(void);
-void proc_switch(void);
-void proc_test(void);
+void proc_yield(void);
+
+int proc_testSetup(void);
+int proc_testRun(void);
+int proc_testTearDown(void);
+
struct Process *proc_current(void);
-iptr_t proc_current_user_data(void);
-void proc_rename(struct Process *proc, const char* name);
+iptr_t proc_currentUserData(void);
+void proc_rename(struct Process *proc, const char *name);
+const char *proc_name(struct Process *proc);
+const char *proc_currentName(void);
-#if CONFIG_KERN_PREEMPTIVE
- void proc_forbid(void);
- void proc_permit(void);
+#if CONFIG_KERN_PRI
+ void proc_setPri(struct Process *proc, int pri);
#else
- INLINE void proc_forbid(void) { /* nop */ }
- INLINE void proc_permit(void) { /* nop */ }
+ INLINE void proc_setPri(UNUSED_ARG(struct Process *,proc), UNUSED_ARG(int, pri))
+ {
+ }
#endif
+/**
+ * Disable preemptive task switching.
+ *
+ * The scheduler maintains a global 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().
+ *
+ * \note Calling functions that could sleep while task switching is disabled
+ * is dangerous and unsupported.
+ *
+ * \note proc_permit() expands inline to 1-2 asm instructions, so it's a
+ * very efficient locking primitive in simple but performance-critical
+ * situations. In all other cases, semaphores offer a more flexible and
+ * fine-grained locking primitive.
+ *
+ * \sa proc_permit()
+ */
+INLINE void proc_forbid(void)
+{
+ #if CONFIG_KERN_PREEMPT
+ // No need to protect against interrupts here.
+ extern int preempt_forbid_cnt;
+ ++preempt_forbid_cnt;
+
+ /*
+ * Make sure preempt_forbid_cnt is flushed to memory so the
+ * preemption softirq will see the correct value from now on.
+ */
+ MEMORY_BARRIER;
+ #endif
+}
+
+/**
+ * Re-enable preemptive task switching.
+ *
+ * \sa proc_forbid()
+ */
+INLINE void proc_permit(void)
+{
+ #if CONFIG_KERN_PREEMPT
+
+ /*
+ * This is to ensure any global state changed by the process gets
+ * flushed to memory before task switching is re-enabled.
+ */
+ MEMORY_BARRIER;
+
+ /* No need to protect against interrupts here. */
+ extern int preempt_forbid_cnt;
+ --preempt_forbid_cnt;
+ ASSERT(preempt_forbid_cnt >= 0);
+
+ /*
+ * This ensures preempt_forbid_cnt is flushed to memory immediately
+ * so the preemption interrupt sees the correct value.
+ */
+ MEMORY_BARRIER;
+
+ #endif
+}
+
+
/**
* Execute a block of \a CODE atomically with respect to task scheduling.
*/
proc_permit(); \
} while(0)
+#ifndef CONFIG_KERN_MINSTACKSIZE
+
+ #if (ARCH & ARCH_EMUL)
+ /* We need a large stack because system libraries are bloated */
+ #define CONFIG_KERN_MINSTACKSIZE 65536
+ #else
+ /**
+ * Default stack size for each thread, in bytes.
+ *
+ * The goal here is to allow a minimal task to save all of its
+ * registers twice, plus push a maximum of 32 variables on the
+ * stack.
+ *
+ * The actual size computed by the default formula is:
+ * AVR: 102
+ * i386: 156
+ * ARM: 164
+ * x86_64: 184
+ *
+ * Note that on most 16bit architectures, interrupts will also
+ * run on the stack of the currently running process. Nested
+ * interrupts will greatly increases the amount of stack space
+ * required per process. Use irqmanager to minimize stack
+ * usage.
+ */
+ #define CONFIG_KERN_MINSTACKSIZE \
+ (CPU_SAVED_REGS_CNT * 2 * sizeof(cpustack_t) \
+ + 32 * sizeof(int))
+ #endif
+#endif
+
+/* Memory fill codes to help debugging */
+#if CONFIG_KERN_MONITOR
+ #include <cpu/types.h>
+ #if (SIZEOF_CPUSTACK_T == 1)
+ /* 8bit cpustack_t */
+ #define CONFIG_KERN_STACKFILLCODE 0xA5
+ #define CONFIG_KERN_MEMFILLCODE 0xDB
+ #elif (SIZEOF_CPUSTACK_T == 2)
+ /* 16bit cpustack_t */
+ #define CONFIG_KERN_STACKFILLCODE 0xA5A5
+ #define CONFIG_KERN_MEMFILLCODE 0xDBDB
+ #elif (SIZEOF_CPUSTACK_T == 4)
+ /* 32bit cpustack_t */
+ #define CONFIG_KERN_STACKFILLCODE 0xA5A5A5A5UL
+ #define CONFIG_KERN_MEMFILLCODE 0xDBDBDBDBUL
+ #elif (SIZEOF_CPUSTACK_T == 8)
+ /* 64bit cpustack_t */
+ #define CONFIG_KERN_STACKFILLCODE 0xA5A5A5A5A5A5A5A5ULL
+ #define CONFIG_KERN_MEMFILLCODE 0xDBDBDBDBDBDBDBDBULL
+ #else
+ #error No cpustack_t size supported!
+ #endif
+#endif
+
#endif /* KERN_PROC_H */
projects / bertos.git / blobdiff