patch-1.3.71 linux/include/asm-sparc/smp_lock.h

• Lines: 58
• Date: Mon Mar 4 08:50:03 1996
• Orig file: v1.3.70/linux/include/asm-sparc/smp_lock.h
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.70/linux/include/asm-sparc/smp_lock.h linux/include/asm-sparc/smp_lock.h
@@ -0,0 +1,57 @@
+/* smp_lock.h: Locking and unlocking the kernel on the Sparc.
+ *
+ * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
+ */
+
+#ifndef __SPARC_SMPLOCK_H
+#define __SPARC_SMPLOCK_H
+
+#ifdef __SMP__
+
+extern _inline_ unsigned char ldstub(klock_t *lock)
+{
+	klock_t retval;
+
+	__asm__ __volatile__("ldstub [%1], %0\n\t" :
+			     "=r" (retval) :
+			     "r" (lock));
+	return retval;
+}
+
+/* Knock knock... */
+extern _inline_ void lock_kernel(void)
+{
+	unsigned long flags;
+	int proc = smp_processor_id();
+
+	save_flags(flags); cli(); /* need this on sparc? */
+	while(ldstub(&kernel_lock)) {
+		if(proc == active_kernel_processor)
+			break;
+		if(test_bit(proc, (unsigned long *)&smp_invalidate_needed))
+			if(clear_bit(proc, (unsigned long *)&smp_invalidate_needed))
+				local_invalidate();
+	}
+	active_kernel_processor = proc;
+	kernel_counter++;
+	restore_flags(flags);
+}
+
+/* I want out... */
+extern _inline_ void unlock_kernel(void)
+{
+	unsigned long flags;
+
+	save_flags(flags); cli(); /* need this on sparc? */
+	if(kernel_counter == 0)
+		panic("Bogus kernel counter.\n");
+	if(!--kernel_counter) {
+		active_kernel_processor = NO_PROC_ID;
+		kernel_lock = KLOCK_CLEAR;
+	}
+	restore_flag(flags);
+}
+
+#endif /* !(__SPARC_SMPLOCK_H) */
+
+#endif /* (__SMP__) */