patch-2.1.92 linux/include/asm-alpha/smp_lock.h

• Lines: 112
• Date: Mon Mar 30 00:21:41 1998
• Orig file: v2.1.91/linux/include/asm-alpha/smp_lock.h
• Orig date: Wed Apr 23 19:01:27 1997

diff -u --recursive --new-file v2.1.91/linux/include/asm-alpha/smp_lock.h linux/include/asm-alpha/smp_lock.h
@@ -10,7 +10,110 @@
 
 #else
 
-#error "We do not support SMP on alpha yet"
+#include <asm/system.h>
+#include <asm/current.h>
+#include <asm/bitops.h>
+#include <asm/hardirq.h>
+
+#define kernel_lock_held() \
+  (klock_info.kernel_flag && (klock_info.akp == smp_processor_id()))
+
+/* Release global kernel lock and global interrupt lock */
+#define release_kernel_lock(task, cpu, depth)		\
+do {							\
+	if ((depth = (task)->lock_depth) != 0) {	\
+		__cli();				\
+		(task)->lock_depth = 0;			\
+		klock_info.akp = NO_PROC_ID;		\
+		klock_info.kernel_flag = 0;		\
+		mb();					\
+	}						\
+	release_irqlock(cpu);				\
+	__sti();					\
+} while (0)
+
+#if 1
+#define DEBUG_KERNEL_LOCK
+#else
+#undef DEBUG_KERNEL_LOCK
+#endif
+
+#ifdef DEBUG_KERNEL_LOCK
+extern void ___lock_kernel(klock_info_t *klip, int cpu, long ipl);
+#else /* DEBUG_KERNEL_LOCK */
+static inline void ___lock_kernel(klock_info_t *klip, int cpu, long ipl)
+{
+	long regx;
+
+	__asm__ __volatile__(
+	"1:	ldl_l	%1,%0;"
+	"	blbs	%1,6f;"
+	"	or	%1,1,%1;"
+	"	stl_c	%1,%0;"
+	"	beq	%1,6f;"
+	"4:	mb\n"
+	".section .text2,\"ax\"\n"
+	"6:	mov %4,$16;"
+	"	call_pal %3;"
+	"7:	ldl %1,%0;"
+	"	blbs %1,7b;"
+	"	bis $31,7,$16;"
+	"	call_pal %3;"
+	"	br 1b\n"
+	".previous"
+	: "=m,=m" (__dummy_lock(klip)), "=&r,=&r" (regx)
+	: "0,0" (__dummy_lock(klip)), "i,i" (PAL_swpipl), "i,r" (ipl)
+	: "$0", "$1", "$16", "$22", "$23", "$24", "$25", "memory"
+	);
+}
+#endif /* DEBUG_KERNEL_LOCK */
+
+#define reacquire_kernel_lock(task, cpu, depth)	\
+do {						\
+  if (depth) {					\
+    long ipl;					\
+    klock_info_t *klip = &klock_info;		\
+    __save_and_cli(ipl);			\
+    ___lock_kernel(klip, cpu, ipl);		\
+    klip->akp = cpu;				\
+    (task)->lock_depth = depth;			\
+    __restore_flags(ipl);			\
+  }						\
+} while (0)
+
+/* The following acquire and release the master kernel global lock,
+ * the idea is that the usage of this mechanmism becomes less and less
+ * as time goes on, to the point where they are no longer needed at all
+ * and can thus disappear.
+ */
+
+#define lock_kernel()				\
+if (current->lock_depth > 0) {			\
+     ++current->lock_depth;			\
+} else {					\
+  long ipl;					\
+  int cpu = smp_processor_id();			\
+  klock_info_t *klip = &klock_info;		\
+  __save_and_cli(ipl);				\
+  ___lock_kernel(klip, cpu, ipl);		\
+  klip->akp = cpu;				\
+  current->lock_depth = 1;			\
+  __restore_flags(ipl);				\
+}
+
+/* Release kernel global lock. */
+#define unlock_kernel()				\
+if (current->lock_depth > 1) {			\
+  --current->lock_depth;			\
+} else {					\
+  long ipl;					\
+  __save_and_cli(ipl);				\
+  klock_info.akp = NO_PROC_ID;			\
+  klock_info.kernel_flag = KLOCK_CLEAR;		\
+  mb();						\
+  current->lock_depth = 0;			\
+  __restore_flags(ipl);				\
+}  
 
 #endif /* __SMP__ */