Unverified Commit c9c0b0ba authored by Palmer Dabbelt's avatar Palmer Dabbelt
Browse files

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: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 4922a3ea

arch/riscv/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -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

+2 −0
Original line number Diff line number Diff line
@@ -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

deleted100644 → 0
+0 −99
Original line number Diff line number Diff line 
/* 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

deleted100644 → 0
+0 −24
Original line number Diff line number Diff line 
/* 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 */