X-Git-Url: https://codewiz.org/gitweb?a=blobdiff_plain;f=bertos%2Fkern%2Fproc.h;h=afb9639f28b68a6c30decee00eae6f220dcc6977;hb=48fa213cd00cd385ee7274baf83761099a6ceead;hp=482fb7a39708f3a1193f1e0b2689322dded7bbbe;hpb=3b33eb4b36445ee045f4cbac27f9331988205467;p=bertos.git

diff --git a/bertos/kern/proc.h b/bertos/kern/proc.h
index 482fb7a3..afb9639f 100644
--- a/bertos/kern/proc.h
+++ b/bertos/kern/proc.h
@@ -41,9 +41,17 @@
 #include "cfg/cfg_kern.h"
 #include <cfg/compiler.h>
 
-#include <cpu/irq.h>
+#if CONFIG_KERN_PREEMPT
+	#include <cfg/debug.h> // ASSERT()
+#endif
 
-/* Fwd decl */
+#include <cpu/types.h> // cpustack_t
+#include <cpu/frame.h> // CPU_SAVED_REGS_CNT
+
+/*
+ * Forward declaration. The definition of struct Process is private to the
+ * scheduler and hidden in proc_p.h.
+ */
 struct Process;
 
 /* Task scheduling services */
@@ -58,24 +66,88 @@ struct Process *proc_new_with_name(const char* name, void (*entry)(void), iptr_t
 
 void proc_exit(void);
 void proc_yield(void);
-#define proc_switch proc_yield /* OBSOLETE */
 
 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_PREEMPT
-	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
+}
+
+extern int preempt_forbid_cnt;
+
 /**
  * Execute a block of \a CODE atomically with respect to task scheduling.
  */
@@ -86,11 +158,11 @@ void proc_rename(struct Process *proc, const char* name);
 		proc_permit(); \
 	} while(0)
 
-#ifndef CONFIG_PROC_DEFSTACKSIZE
+#ifndef CONFIG_KERN_MINSTACKSIZE
 
 	#if (ARCH & ARCH_EMUL)
 		/* We need a large stack because system libraries are bloated */
-		#define CONFIG_PROC_DEFSTACKSIZE  65536
+		#define CONFIG_KERN_MINSTACKSIZE  65536
 	#else
 		/**
 		 * Default stack size for each thread, in bytes.
@@ -111,7 +183,7 @@ void proc_rename(struct Process *proc, const char* name);
 		 * required per process.  Use irqmanager to minimize stack
 		 * usage.
 		 */
-		#define CONFIG_PROC_DEFSTACKSIZE  \
+		#define CONFIG_KERN_MINSTACKSIZE  \
 		    (CPU_SAVED_REGS_CNT * 2 * sizeof(cpustack_t) \
 		    + 32 * sizeof(int))
 	#endif