1 files changed, 148 insertions, 0 deletions
diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h
new file mode 100644
index 000000000..37127cd77
--- /dev/null
+++ b/arch/s390/include/asm/spinlock.h
@@ -0,0 +1,148 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ *  S390 version
+ *    Copyright IBM Corp. 1999
+ *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
+ *
+ *  Derived from "include/asm-i386/spinlock.h"
+ */
+
+#ifndef __ASM_SPINLOCK_H
+#define __ASM_SPINLOCK_H
+
+#include <linux/smp.h>
+#include <asm/atomic_ops.h>
+#include <asm/barrier.h>
+#include <asm/processor.h>
+#include <asm/alternative.h>
+
+#define SPINLOCK_LOCKVAL (S390_lowcore.spinlock_lockval)
+
+extern int spin_retry;
+
+bool arch_vcpu_is_preempted(int cpu);
+
+#define vcpu_is_preempted arch_vcpu_is_preempted
+
+/*
+ * Simple spin lock operations.  There are two variants, one clears IRQ's
+ * on the local processor, one does not.
+ *
+ * We make no fairness assumptions. They have a cost.
+ *
+ * (the type definitions are in asm/spinlock_types.h)
+ */
+
+void arch_spin_relax(arch_spinlock_t *lock);
+#define arch_spin_relax	arch_spin_relax
+
+void arch_spin_lock_wait(arch_spinlock_t *);
+int arch_spin_trylock_retry(arch_spinlock_t *);
+void arch_spin_lock_setup(int cpu);
+
+static inline u32 arch_spin_lockval(int cpu)
+{
+	return cpu + 1;
+}
+
+static inline int arch_spin_value_unlocked(arch_spinlock_t lock)
+{
+	return lock.lock == 0;
+}
+
+static inline int arch_spin_is_locked(arch_spinlock_t *lp)
+{
+	return READ_ONCE(lp->lock) != 0;
+}
+
+static inline int arch_spin_trylock_once(arch_spinlock_t *lp)
+{
+	barrier();
+	return likely(__atomic_cmpxchg_bool(&lp->lock, 0, SPINLOCK_LOCKVAL));
+}
+
+static inline void arch_spin_lock(arch_spinlock_t *lp)
+{
+	if (!arch_spin_trylock_once(lp))
+		arch_spin_lock_wait(lp);
+}
+
+static inline int arch_spin_trylock(arch_spinlock_t *lp)
+{
+	if (!arch_spin_trylock_once(lp))
+		return arch_spin_trylock_retry(lp);
+	return 1;
+}
+
+static inline void arch_spin_unlock(arch_spinlock_t *lp)
+{
+	typecheck(int, lp->lock);
+	kcsan_release();
+	asm_inline volatile(
+		ALTERNATIVE("nop", ".insn rre,0xb2fa0000,7,0", 49) /* NIAI 7 */
+		"	sth	%1,%0\n"
+		: "=R" (((unsigned short *) &lp->lock)[1])
+		: "d" (0) : "cc", "memory");
+}
+
+/*
+ * Read-write spinlocks, allowing multiple readers
+ * but only one writer.
+ *
+ * NOTE! it is quite common to have readers in interrupts
+ * but no interrupt writers. For those circumstances we
+ * can "mix" irq-safe locks - any writer needs to get a
+ * irq-safe write-lock, but readers can get non-irqsafe
+ * read-locks.
+ */
+
+#define arch_read_relax(rw) barrier()
+#define arch_write_relax(rw) barrier()
+
+void arch_read_lock_wait(arch_rwlock_t *lp);
+void arch_write_lock_wait(arch_rwlock_t *lp);
+
+static inline void arch_read_lock(arch_rwlock_t *rw)
+{
+	int old;
+
+	old = __atomic_add(1, &rw->cnts);
+	if (old & 0xffff0000)
+		arch_read_lock_wait(rw);
+}
+
+static inline void arch_read_unlock(arch_rwlock_t *rw)
+{
+	__atomic_add_const_barrier(-1, &rw->cnts);
+}
+
+static inline void arch_write_lock(arch_rwlock_t *rw)
+{
+	if (!__atomic_cmpxchg_bool(&rw->cnts, 0, 0x30000))
+		arch_write_lock_wait(rw);
+}
+
+static inline void arch_write_unlock(arch_rwlock_t *rw)
+{
+	__atomic_add_barrier(-0x30000, &rw->cnts);
+}
+
+
+static inline int arch_read_trylock(arch_rwlock_t *rw)
+{
+	int old;
+
+	old = READ_ONCE(rw->cnts);
+	return (!(old & 0xffff0000) &&
+		__atomic_cmpxchg_bool(&rw->cnts, old, old + 1));
+}
+
+static inline int arch_write_trylock(arch_rwlock_t *rw)
+{
+	int old;
+
+	old = READ_ONCE(rw->cnts);
+	return !old && __atomic_cmpxchg_bool(&rw->cnts, 0, 0x30000);
+}
+
+#endif /* __ASM_SPINLOCK_H */