1 files changed, 51 insertions, 166 deletions

diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h
index f7838ecd83c6..b06b183b7246 100644
--- a/arch/s390/include/asm/spinlock.h
+++ b/arch/s390/include/asm/spinlock.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  *  S390 version
  *    Copyright IBM Corp. 1999
@@ -13,16 +14,29 @@
 #include <asm/atomic_ops.h>
 #include <asm/barrier.h>
 #include <asm/processor.h>
+#include <asm/alternative.h>
 
-#define SPINLOCK_LOCKVAL (S390_lowcore.spinlock_lockval)
+static __always_inline unsigned int spinlock_lockval(void)
+{
+	unsigned long lc_lockval;
+	unsigned int lockval;
+
+	BUILD_BUG_ON(sizeof_field(struct lowcore, spinlock_lockval) != sizeof(lockval));
+	lc_lockval = offsetof(struct lowcore, spinlock_lockval);
+	asm_inline(
+		ALTERNATIVE("   ly      %[lockval],%[offzero](%%r0)\n",
+			    "   ly      %[lockval],%[offalt](%%r0)\n",
+			    ALT_FEATURE(MFEATURE_LOWCORE))
+		: [lockval] "=d" (lockval)
+		: [offzero] "i" (lc_lockval),
+		  [offalt] "i" (lc_lockval + LOWCORE_ALT_ADDRESS),
+		  "m" (((struct lowcore *)0)->spinlock_lockval));
+	return lockval;
+}
 
 extern int spin_retry;
 
-#ifndef CONFIG_SMP
-static inline bool arch_vcpu_is_preempted(int cpu) { return false; }
-#else
 bool arch_vcpu_is_preempted(int cpu);
-#endif
 
 #define vcpu_is_preempted arch_vcpu_is_preempted
 
@@ -35,20 +49,16 @@ bool arch_vcpu_is_preempted(int cpu);
  * (the type definitions are in asm/spinlock_types.h)
  */
 
-void arch_lock_relax(int cpu);
+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_wait_flags(arch_spinlock_t *, unsigned long flags);
-
-static inline void arch_spin_relax(arch_spinlock_t *lock)
-{
-	arch_lock_relax(lock->lock);
-}
+void arch_spin_lock_setup(int cpu);
 
 static inline u32 arch_spin_lockval(int cpu)
 {
-	return ~cpu;
+	return cpu + 1;
 }
 
 static inline int arch_spin_value_unlocked(arch_spinlock_t lock)
@@ -63,9 +73,10 @@ static inline int arch_spin_is_locked(arch_spinlock_t *lp)
 
 static inline int arch_spin_trylock_once(arch_spinlock_t *lp)
 {
+	int old = 0;
+
 	barrier();
-	return likely(arch_spin_value_unlocked(*lp) &&
-		      __atomic_cmpxchg_bool(&lp->lock, 0, SPINLOCK_LOCKVAL));
+	return likely(arch_try_cmpxchg(&lp->lock, &old, spinlock_lockval()));
 }
 
 static inline void arch_spin_lock(arch_spinlock_t *lp)
@@ -74,13 +85,6 @@ static inline void arch_spin_lock(arch_spinlock_t *lp)
 		arch_spin_lock_wait(lp);
 }
 
-static inline void arch_spin_lock_flags(arch_spinlock_t *lp,
-					unsigned long flags)
-{
-	if (!arch_spin_trylock_once(lp))
-		arch_spin_lock_wait_flags(lp, flags);
-}
-
 static inline int arch_spin_trylock(arch_spinlock_t *lp)
 {
 	if (!arch_spin_trylock_once(lp))
@@ -91,18 +95,13 @@ static inline int arch_spin_trylock(arch_spinlock_t *lp)
 static inline void arch_spin_unlock(arch_spinlock_t *lp)
 {
 	typecheck(int, lp->lock);
-	asm volatile(
-		"st	%1,%0\n"
-		: "+Q" (lp->lock)
-		: "d" (0)
-		: "cc", "memory");
-}
-
-static inline void arch_spin_unlock_wait(arch_spinlock_t *lock)
-{
-	while (arch_spin_is_locked(lock))
-		arch_spin_relax(lock);
-	smp_acquire__after_ctrl_dep();
+	kcsan_release();
+	asm_inline volatile(
+		ALTERNATIVE("nop", ".insn rre,0xb2fa0000,7,0", ALT_FACILITY(49)) /* NIAI 7 */
+		"	mvhhi	%[lock],0"
+		: [lock] "=Q" (((unsigned short *)&lp->lock)[1])
+		:
+		: "memory");
 }
 
 /*
@@ -116,168 +115,54 @@ static inline void arch_spin_unlock_wait(arch_spinlock_t *lock)
  * read-locks.
  */
 
-/**
- * read_can_lock - would read_trylock() succeed?
- * @lock: the rwlock in question.
- */
-#define arch_read_can_lock(x) ((int)(x)->lock >= 0)
-
-/**
- * write_can_lock - would write_trylock() succeed?
- * @lock: the rwlock in question.
- */
-#define arch_write_can_lock(x) ((x)->lock == 0)
-
-extern int _raw_read_trylock_retry(arch_rwlock_t *lp);
-extern int _raw_write_trylock_retry(arch_rwlock_t *lp);
+#define arch_read_relax(rw) barrier()
+#define arch_write_relax(rw) barrier()
 
-#define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
-#define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
-
-static inline int arch_read_trylock_once(arch_rwlock_t *rw)
-{
-	int old = ACCESS_ONCE(rw->lock);
-	return likely(old >= 0 &&
-		      __atomic_cmpxchg_bool(&rw->lock, old, old + 1));
-}
-
-static inline int arch_write_trylock_once(arch_rwlock_t *rw)
-{
-	int old = ACCESS_ONCE(rw->lock);
-	return likely(old == 0 &&
-		      __atomic_cmpxchg_bool(&rw->lock, 0, 0x80000000));
-}
-
-#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
-
-#define __RAW_OP_OR	"lao"
-#define __RAW_OP_AND	"lan"
-#define __RAW_OP_ADD	"laa"
-
-#define __RAW_LOCK(ptr, op_val, op_string)		\
-({							\
-	int old_val;					\
-							\
-	typecheck(int *, ptr);				\
-	asm volatile(					\
-		op_string "	%0,%2,%1\n"		\
-		"bcr	14,0\n"				\
-		: "=d" (old_val), "+Q" (*ptr)		\
-		: "d" (op_val)				\
-		: "cc", "memory");			\
-	old_val;					\
-})
-
-#define __RAW_UNLOCK(ptr, op_val, op_string)		\
-({							\
-	int old_val;					\
-							\
-	typecheck(int *, ptr);				\
-	asm volatile(					\
-		op_string "	%0,%2,%1\n"		\
-		: "=d" (old_val), "+Q" (*ptr)		\
-		: "d" (op_val)				\
-		: "cc", "memory");			\
-	old_val;					\
-})
-
-extern void _raw_read_lock_wait(arch_rwlock_t *lp);
-extern void _raw_write_lock_wait(arch_rwlock_t *lp, int prev);
+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 = __RAW_LOCK(&rw->lock, 1, __RAW_OP_ADD);
-	if (old < 0)
-		_raw_read_lock_wait(rw);
+	old = __atomic_add(1, &rw->cnts);
+	if (old & 0xffff0000)
+		arch_read_lock_wait(rw);
 }
 
 static inline void arch_read_unlock(arch_rwlock_t *rw)
 {
-	__RAW_UNLOCK(&rw->lock, -1, __RAW_OP_ADD);
+	__atomic_add_const_barrier(-1, &rw->cnts);
 }
 
 static inline void arch_write_lock(arch_rwlock_t *rw)
 {
-	int old;
+	int old = 0;
 
-	old = __RAW_LOCK(&rw->lock, 0x80000000, __RAW_OP_OR);
-	if (old != 0)
-		_raw_write_lock_wait(rw, old);
-	rw->owner = SPINLOCK_LOCKVAL;
+	if (!arch_try_cmpxchg(&rw->cnts, &old, 0x30000))
+		arch_write_lock_wait(rw);
 }
 
 static inline void arch_write_unlock(arch_rwlock_t *rw)
 {
-	rw->owner = 0;
-	__RAW_UNLOCK(&rw->lock, 0x7fffffff, __RAW_OP_AND);
+	__atomic_add_barrier(-0x30000, &rw->cnts);
 }
 
-#else /* CONFIG_HAVE_MARCH_Z196_FEATURES */
-
-extern void _raw_read_lock_wait(arch_rwlock_t *lp);
-extern void _raw_write_lock_wait(arch_rwlock_t *lp);
 
-static inline void arch_read_lock(arch_rwlock_t *rw)
-{
-	if (!arch_read_trylock_once(rw))
-		_raw_read_lock_wait(rw);
-}
-
-static inline void arch_read_unlock(arch_rwlock_t *rw)
+static inline int arch_read_trylock(arch_rwlock_t *rw)
 {
 	int old;
 
-	do {
-		old = ACCESS_ONCE(rw->lock);
-	} while (!__atomic_cmpxchg_bool(&rw->lock, old, old - 1));
-}
-
-static inline void arch_write_lock(arch_rwlock_t *rw)
-{
-	if (!arch_write_trylock_once(rw))
-		_raw_write_lock_wait(rw);
-	rw->owner = SPINLOCK_LOCKVAL;
-}
-
-static inline void arch_write_unlock(arch_rwlock_t *rw)
-{
-	typecheck(int, rw->lock);
-
-	rw->owner = 0;
-	asm volatile(
-		"st	%1,%0\n"
-		: "+Q" (rw->lock)
-		: "d" (0)
-		: "cc", "memory");
-}
-
-#endif /* CONFIG_HAVE_MARCH_Z196_FEATURES */
-
-static inline int arch_read_trylock(arch_rwlock_t *rw)
-{
-	if (!arch_read_trylock_once(rw))
-		return _raw_read_trylock_retry(rw);
-	return 1;
+	old = READ_ONCE(rw->cnts);
+	return (!(old & 0xffff0000) && arch_try_cmpxchg(&rw->cnts, &old, old + 1));
 }
 
 static inline int arch_write_trylock(arch_rwlock_t *rw)
 {
-	if (!arch_write_trylock_once(rw) && !_raw_write_trylock_retry(rw))
-		return 0;
-	rw->owner = SPINLOCK_LOCKVAL;
-	return 1;
-}
-
-static inline void arch_read_relax(arch_rwlock_t *rw)
-{
-	arch_lock_relax(rw->owner);
-}
+	int old;
 
-static inline void arch_write_relax(arch_rwlock_t *rw)
-{
-	arch_lock_relax(rw->owner);
+	old = READ_ONCE(rw->cnts);
+	return !old && arch_try_cmpxchg(&rw->cnts, &old, 0x30000);
 }
 
 #endif /* __ASM_SPINLOCK_H */