RISC-V: Move to queued RW locks

Now that we have fair spinlocks we can use the generic queued rwlocks,
so we might as well do so.
Reviewed-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NPalmer Dabbelt <palmer@rivosinc.com>

arch/riscv/Kconfig

@@ -39,6 +39,7 @@ config RISCV
 	select ARCH_SUPPORTS_DEBUG_PAGEALLOC if MMU
 	select ARCH_SUPPORTS_HUGETLBFS if MMU
 	select ARCH_USE_MEMTEST
+	select ARCH_USE_QUEUED_RWLOCKS
 	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
 	select ARCH_WANT_FRAME_POINTERS
 	select ARCH_WANT_GENERAL_HUGETLB

arch/riscv/include/asm/Kbuild

@@ -3,6 +3,8 @@ generic-y += early_ioremap.h
 generic-y += flat.h
 generic-y += kvm_para.h
 generic-y += parport.h
+generic-y += spinlock.h
+generic-y += spinlock_types.h
 generic-y += qrwlock.h
 generic-y += qrwlock_types.h
 generic-y += user.h

arch/riscv/include/asm/spinlock.h

-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * Copyright (C) 2015 Regents of the University of California
- * Copyright (C) 2017 SiFive
- */
-
-#ifndef _ASM_RISCV_SPINLOCK_H
-#define _ASM_RISCV_SPINLOCK_H
-
-/* This is horible, but the whole file is going away in the next commit. */
-#define __ASM_GENERIC_QRWLOCK_H
-
-#include <linux/kernel.h>
-#include <asm/current.h>
-#include <asm/fence.h>
-#include <asm-generic/spinlock.h>
-
-static inline void arch_read_lock(arch_rwlock_t *lock)
-{
-	int tmp;
-
-	__asm__ __volatile__(
-		"1:	lr.w	%1, %0\n"
-		"	bltz	%1, 1b\n"
-		"	addi	%1, %1, 1\n"
-		"	sc.w	%1, %1, %0\n"
-		"	bnez	%1, 1b\n"
-		RISCV_ACQUIRE_BARRIER
-		: "+A" (lock->lock), "=&r" (tmp)
-		:: "memory");
-}
-
-static inline void arch_write_lock(arch_rwlock_t *lock)
-{
-	int tmp;
-
-	__asm__ __volatile__(
-		"1:	lr.w	%1, %0\n"
-		"	bnez	%1, 1b\n"
-		"	li	%1, -1\n"
-		"	sc.w	%1, %1, %0\n"
-		"	bnez	%1, 1b\n"
-		RISCV_ACQUIRE_BARRIER
-		: "+A" (lock->lock), "=&r" (tmp)
-		:: "memory");
-}
-
-static inline int arch_read_trylock(arch_rwlock_t *lock)
-{
-	int busy;
-
-	__asm__ __volatile__(
-		"1:	lr.w	%1, %0\n"
-		"	bltz	%1, 1f\n"
-		"	addi	%1, %1, 1\n"
-		"	sc.w	%1, %1, %0\n"
-		"	bnez	%1, 1b\n"
-		RISCV_ACQUIRE_BARRIER
-		"1:\n"
-		: "+A" (lock->lock), "=&r" (busy)
-		:: "memory");
-
-	return !busy;
-}
-
-static inline int arch_write_trylock(arch_rwlock_t *lock)
-{
-	int busy;
-
-	__asm__ __volatile__(
-		"1:	lr.w	%1, %0\n"
-		"	bnez	%1, 1f\n"
-		"	li	%1, -1\n"
-		"	sc.w	%1, %1, %0\n"
-		"	bnez	%1, 1b\n"
-		RISCV_ACQUIRE_BARRIER
-		"1:\n"
-		: "+A" (lock->lock), "=&r" (busy)
-		:: "memory");
-
-	return !busy;
-}
-
-static inline void arch_read_unlock(arch_rwlock_t *lock)
-{
-	__asm__ __volatile__(
-		RISCV_RELEASE_BARRIER
-		"	amoadd.w x0, %1, %0\n"
-		: "+A" (lock->lock)
-		: "r" (-1)
-		: "memory");
-}
-
-static inline void arch_write_unlock(arch_rwlock_t *lock)
-{
-	smp_store_release(&lock->lock, 0);
-}
-
-#endif /* _ASM_RISCV_SPINLOCK_H */

arch/riscv/include/asm/spinlock_types.h

-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * Copyright (C) 2015 Regents of the University of California
- */
-
-#ifndef _ASM_RISCV_SPINLOCK_TYPES_H
-#define _ASM_RISCV_SPINLOCK_TYPES_H
-
-/* This is horible, but the whole file is going away in the next commit. */
-#define __ASM_GENERIC_QRWLOCK_TYPES_H
-
-#ifndef __LINUX_SPINLOCK_TYPES_RAW_H
-# error "please don't include this file directly"
-#endif
-
-#include <asm-generic/spinlock_types.h>
-
-typedef struct {
-	volatile unsigned int lock;
-} arch_rwlock_t;
-
-#define __ARCH_RW_LOCK_UNLOCKED		{ 0 }
-
-#endif /* _ASM_RISCV_SPINLOCK_TYPES_H */