1 files changed, 376 insertions, 0 deletions
diff --git a/arch/sparc64/lib/debuglocks.c b/arch/sparc64/lib/debuglocks.c
new file mode 100644
index 00000000000..c421e0c6532
--- /dev/null
+++ b/arch/sparc64/lib/debuglocks.c
@@ -0,0 +1,376 @@
+/* $Id: debuglocks.c,v 1.9 2001/11/17 00:10:48 davem Exp $
+ * debuglocks.c: Debugging versions of SMP locking primitives.
+ *
+ * Copyright (C) 1998 David S. Miller (davem@redhat.com)
+ */
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <asm/system.h>
+
+#ifdef CONFIG_SMP
+
+#define GET_CALLER(PC) __asm__ __volatile__("mov %%i7, %0" : "=r" (PC))
+
+static inline void show (char *str, spinlock_t *lock, unsigned long caller)
+{
+	int cpu = smp_processor_id();
+
+	printk("%s(%p) CPU#%d stuck at %08x, owner PC(%08x):CPU(%x)\n",
+	       str, lock, cpu, (unsigned int) caller,
+	       lock->owner_pc, lock->owner_cpu);
+}
+
+static inline void show_read (char *str, rwlock_t *lock, unsigned long caller)
+{
+	int cpu = smp_processor_id();
+
+	printk("%s(%p) CPU#%d stuck at %08x, writer PC(%08x):CPU(%x)\n",
+	       str, lock, cpu, (unsigned int) caller,
+	       lock->writer_pc, lock->writer_cpu);
+}
+
+static inline void show_write (char *str, rwlock_t *lock, unsigned long caller)
+{
+	int cpu = smp_processor_id();
+	int i;
+
+	printk("%s(%p) CPU#%d stuck at %08x\n",
+	       str, lock, cpu, (unsigned int) caller);
+	printk("Writer: PC(%08x):CPU(%x)\n",
+	       lock->writer_pc, lock->writer_cpu);
+	printk("Readers:");
+	for (i = 0; i < NR_CPUS; i++)
+		if (lock->reader_pc[i])
+			printk(" %d[%08x]", i, lock->reader_pc[i]);
+	printk("\n");
+}
+
+#undef INIT_STUCK
+#define INIT_STUCK 100000000
+
+void _do_spin_lock(spinlock_t *lock, char *str)
+{
+	unsigned long caller, val;
+	int stuck = INIT_STUCK;
+	int cpu = get_cpu();
+	int shown = 0;
+
+	GET_CALLER(caller);
+again:
+	__asm__ __volatile__("ldstub [%1], %0"
+			     : "=r" (val)
+			     : "r" (&(lock->lock))
+			     : "memory");
+	membar("#StoreLoad | #StoreStore");
+	if (val) {
+		while (lock->lock) {
+			if (!--stuck) {
+				if (shown++ <= 2)
+					show(str, lock, caller);
+				stuck = INIT_STUCK;
+			}
+			membar("#LoadLoad");
+		}
+		goto again;
+	}
+	lock->owner_pc = ((unsigned int)caller);
+	lock->owner_cpu = cpu;
+	current->thread.smp_lock_count++;
+	current->thread.smp_lock_pc = ((unsigned int)caller);
+
+	put_cpu();
+}
+
+int _do_spin_trylock(spinlock_t *lock)
+{
+	unsigned long val, caller;
+	int cpu = get_cpu();
+
+	GET_CALLER(caller);
+	__asm__ __volatile__("ldstub [%1], %0"
+			     : "=r" (val)
+			     : "r" (&(lock->lock))
+			     : "memory");
+	membar("#StoreLoad | #StoreStore");
+	if (!val) {
+		lock->owner_pc = ((unsigned int)caller);
+		lock->owner_cpu = cpu;
+		current->thread.smp_lock_count++;
+		current->thread.smp_lock_pc = ((unsigned int)caller);
+	}
+
+	put_cpu();
+
+	return val == 0;
+}
+
+void _do_spin_unlock(spinlock_t *lock)
+{
+	lock->owner_pc = 0;
+	lock->owner_cpu = NO_PROC_ID;
+	membar("#StoreStore | #LoadStore");
+	lock->lock = 0;
+	current->thread.smp_lock_count--;
+}
+
+/* Keep INIT_STUCK the same... */
+
+void _do_read_lock (rwlock_t *rw, char *str)
+{
+	unsigned long caller, val;
+	int stuck = INIT_STUCK;
+	int cpu = get_cpu();
+	int shown = 0;
+
+	GET_CALLER(caller);
+wlock_again:
+	/* Wait for any writer to go away.  */
+	while (((long)(rw->lock)) < 0) {
+		if (!--stuck) {
+			if (shown++ <= 2)
+				show_read(str, rw, caller);
+			stuck = INIT_STUCK;
+		}
+		membar("#LoadLoad");
+	}
+	/* Try once to increment the counter.  */
+	__asm__ __volatile__(
+"	ldx		[%0], %%g1\n"
+"	brlz,a,pn	%%g1, 2f\n"
+"	 mov		1, %0\n"
+"	add		%%g1, 1, %%g7\n"
+"	casx		[%0], %%g1, %%g7\n"
+"	sub		%%g1, %%g7, %0\n"
+"2:"	: "=r" (val)
+	: "0" (&(rw->lock))
+	: "g1", "g7", "memory");
+	membar("#StoreLoad | #StoreStore");
+	if (val)
+		goto wlock_again;
+	rw->reader_pc[cpu] = ((unsigned int)caller);
+	current->thread.smp_lock_count++;
+	current->thread.smp_lock_pc = ((unsigned int)caller);
+
+	put_cpu();
+}
+
+void _do_read_unlock (rwlock_t *rw, char *str)
+{
+	unsigned long caller, val;
+	int stuck = INIT_STUCK;
+	int cpu = get_cpu();
+	int shown = 0;
+
+	GET_CALLER(caller);
+
+	/* Drop our identity _first_. */
+	rw->reader_pc[cpu] = 0;
+	current->thread.smp_lock_count--;
+runlock_again:
+	/* Spin trying to decrement the counter using casx.  */
+	__asm__ __volatile__(
+"	membar	#StoreLoad | #LoadLoad\n"
+"	ldx	[%0], %%g1\n"
+"	sub	%%g1, 1, %%g7\n"
+"	casx	[%0], %%g1, %%g7\n"
+"	membar	#StoreLoad | #StoreStore\n"
+"	sub	%%g1, %%g7, %0\n"
+	: "=r" (val)
+	: "0" (&(rw->lock))
+	: "g1", "g7", "memory");
+	if (val) {
+		if (!--stuck) {
+			if (shown++ <= 2)
+				show_read(str, rw, caller);
+			stuck = INIT_STUCK;
+		}
+		goto runlock_again;
+	}
+
+	put_cpu();
+}
+
+void _do_write_lock (rwlock_t *rw, char *str)
+{
+	unsigned long caller, val;
+	int stuck = INIT_STUCK;
+	int cpu = get_cpu();
+	int shown = 0;
+
+	GET_CALLER(caller);
+wlock_again:
+	/* Spin while there is another writer. */
+	while (((long)rw->lock) < 0) {
+		if (!--stuck) {
+			if (shown++ <= 2)
+				show_write(str, rw, caller);
+			stuck = INIT_STUCK;
+		}
+		membar("#LoadLoad");
+	}
+
+	/* Try to acuire the write bit.  */
+	__asm__ __volatile__(
+"	mov	1, %%g3\n"
+"	sllx	%%g3, 63, %%g3\n"
+"	ldx	[%0], %%g1\n"
+"	brlz,pn	%%g1, 1f\n"
+"	 or	%%g1, %%g3, %%g7\n"
+"	casx	[%0], %%g1, %%g7\n"
+"	membar	#StoreLoad | #StoreStore\n"
+"	ba,pt	%%xcc, 2f\n"
+"	 sub	%%g1, %%g7, %0\n"
+"1:	mov	1, %0\n"
+"2:"	: "=r" (val)
+	: "0" (&(rw->lock))
+	: "g3", "g1", "g7", "memory");
+	if (val) {
+		/* We couldn't get the write bit. */
+		if (!--stuck) {
+			if (shown++ <= 2)
+				show_write(str, rw, caller);
+			stuck = INIT_STUCK;
+		}
+		goto wlock_again;
+	}
+	if ((rw->lock & ((1UL<<63)-1UL)) != 0UL) {
+		/* Readers still around, drop the write
+		 * lock, spin, and try again.
+		 */
+		if (!--stuck) {
+			if (shown++ <= 2)
+				show_write(str, rw, caller);
+			stuck = INIT_STUCK;
+		}
+		__asm__ __volatile__(
+"		mov	1, %%g3\n"
+"		sllx	%%g3, 63, %%g3\n"
+"1:		ldx	[%0], %%g1\n"
+"		andn	%%g1, %%g3, %%g7\n"
+"		casx	[%0], %%g1, %%g7\n"
+"		cmp	%%g1, %%g7\n"
+"		bne,pn	%%xcc, 1b\n"
+"		 membar	#StoreLoad | #StoreStore"
+		: /* no outputs */
+		: "r" (&(rw->lock))
+		: "g3", "g1", "g7", "cc", "memory");
+		while(rw->lock != 0) {
+			if (!--stuck) {
+				if (shown++ <= 2)
+					show_write(str, rw, caller);
+				stuck = INIT_STUCK;
+			}
+			membar("#LoadLoad");
+		}
+		goto wlock_again;
+	}
+
+	/* We have it, say who we are. */
+	rw->writer_pc = ((unsigned int)caller);
+	rw->writer_cpu = cpu;
+	current->thread.smp_lock_count++;
+	current->thread.smp_lock_pc = ((unsigned int)caller);
+
+	put_cpu();
+}
+
+void _do_write_unlock(rwlock_t *rw)
+{
+	unsigned long caller, val;
+	int stuck = INIT_STUCK;
+	int shown = 0;
+
+	GET_CALLER(caller);
+
+	/* Drop our identity _first_ */
+	rw->writer_pc = 0;
+	rw->writer_cpu = NO_PROC_ID;
+	current->thread.smp_lock_count--;
+wlock_again:
+	__asm__ __volatile__(
+"	membar	#StoreLoad | #LoadLoad\n"
+"	mov	1, %%g3\n"
+"	sllx	%%g3, 63, %%g3\n"
+"	ldx	[%0], %%g1\n"
+"	andn	%%g1, %%g3, %%g7\n"
+"	casx	[%0], %%g1, %%g7\n"
+"	membar	#StoreLoad | #StoreStore\n"
+"	sub	%%g1, %%g7, %0\n"
+	: "=r" (val)
+	: "0" (&(rw->lock))
+	: "g3", "g1", "g7", "memory");
+	if (val) {
+		if (!--stuck) {
+			if (shown++ <= 2)
+				show_write("write_unlock", rw, caller);
+			stuck = INIT_STUCK;
+		}
+		goto wlock_again;
+	}
+}
+
+int _do_write_trylock (rwlock_t *rw, char *str)
+{
+	unsigned long caller, val;
+	int cpu = get_cpu();
+
+	GET_CALLER(caller);
+
+	/* Try to acuire the write bit.  */
+	__asm__ __volatile__(
+"	mov	1, %%g3\n"
+"	sllx	%%g3, 63, %%g3\n"
+"	ldx	[%0], %%g1\n"
+"	brlz,pn	%%g1, 1f\n"
+"	 or	%%g1, %%g3, %%g7\n"
+"	casx	[%0], %%g1, %%g7\n"
+"	membar	#StoreLoad | #StoreStore\n"
+"	ba,pt	%%xcc, 2f\n"
+"	 sub	%%g1, %%g7, %0\n"
+"1:	mov	1, %0\n"
+"2:"	: "=r" (val)
+	: "0" (&(rw->lock))
+	: "g3", "g1", "g7", "memory");
+
+	if (val) {
+		put_cpu();
+		return 0;
+	}
+
+	if ((rw->lock & ((1UL<<63)-1UL)) != 0UL) {
+		/* Readers still around, drop the write
+		 * lock, return failure.
+		 */
+		__asm__ __volatile__(
+"		mov	1, %%g3\n"
+"		sllx	%%g3, 63, %%g3\n"
+"1:		ldx	[%0], %%g1\n"
+"		andn	%%g1, %%g3, %%g7\n"
+"		casx	[%0], %%g1, %%g7\n"
+"		cmp	%%g1, %%g7\n"
+"		bne,pn	%%xcc, 1b\n"
+"		 membar	#StoreLoad | #StoreStore"
+		: /* no outputs */
+		: "r" (&(rw->lock))
+		: "g3", "g1", "g7", "cc", "memory");
+
+		put_cpu();
+
+		return 0;
+	}
+
+	/* We have it, say who we are. */
+	rw->writer_pc = ((unsigned int)caller);
+	rw->writer_cpu = cpu;
+	current->thread.smp_lock_count++;
+	current->thread.smp_lock_pc = ((unsigned int)caller);
+
+	put_cpu();
+
+	return 1;
+}
+
+#endif /* CONFIG_SMP */