[PATCH v4 4/4] riscv: Convert custom spinlock/rwlock to generic qspinlock/qrwlock

guoren
2021-03-27T18:07:59Z

From: Michael Clark <michaeljclark@mac.com>

Update the RISC-V port to use the generic qspinlock and qrwlock.

This patch requires support for xchg for short which are added by
a previous patch.

Guo fixed up compile error which made by below include sequence:
+#include <asm/qrwlock.h>
+#include <asm/qspinlock.h>

Signed-off-by: Michael Clark <michaeljclark@mac.com>
Co-developed-by: Guo Ren <guoren@linux.alibaba.com>
Tested-by: Guo Ren <guoren@linux.alibaba.com>
Link: https://lore.kernel.org/linux-riscv/20190211043829.30096-3-michaeljclark@mac.com/
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Anup Patel <anup@brainfault.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
---
arch/riscv/Kconfig | 3 +
arch/riscv/include/asm/Kbuild | 3 +
arch/riscv/include/asm/spinlock.h | 126 +-----------------------
arch/riscv/include/asm/spinlock_types.h | 15 +--
4 files changed, 11 insertions(+), 136 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 87d7b52f278f..67cc65ba1ea1 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -33,6 +33,9 @@ config RISCV
select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
select ARCH_WANT_FRAME_POINTERS
select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
+ select ARCH_USE_QUEUED_RWLOCKS
+ select ARCH_USE_QUEUED_SPINLOCKS
+ select ARCH_USE_QUEUED_SPINLOCKS_XCHG32
select CLONE_BACKWARDS
select CLINT_TIMER if !MMU
select COMMON_CLK
diff --git a/arch/riscv/include/asm/Kbuild b/arch/riscv/include/asm/Kbuild
index 445ccc97305a..750c1056b90f 100644
--- a/arch/riscv/include/asm/Kbuild
+++ b/arch/riscv/include/asm/Kbuild
@@ -3,5 +3,8 @@ generic-y += early_ioremap.h
generic-y += extable.h
generic-y += flat.h
generic-y += kvm_para.h
+generic-y += mcs_spinlock.h
+generic-y += qrwlock.h
+generic-y += qspinlock.h
generic-y += user.h
generic-y += vmlinux.lds.h
diff --git a/arch/riscv/include/asm/spinlock.h b/arch/riscv/include/asm/spinlock.h
index f4f7fa1b7ca8..a557de67a425 100644
--- a/arch/riscv/include/asm/spinlock.h
+++ b/arch/riscv/include/asm/spinlock.h
@@ -7,129 +7,7 @@
#ifndef _ASM_RISCV_SPINLOCK_H
#define _ASM_RISCV_SPINLOCK_H

-#include <linux/kernel.h>
-#include <asm/current.h>
-#include <asm/fence.h>
-
-/*
- * Simple spin lock operations. These provide no fairness guarantees.
- */
-
-/* FIXME: Replace this with a ticket lock, like MIPS. */
-
-#define arch_spin_is_locked(x) (READ_ONCE((x)->lock) != 0)
-
-static inline void arch_spin_unlock(arch_spinlock_t *lock)
-{
- smp_store_release(&lock->lock, 0);
-}
-
-static inline int arch_spin_trylock(arch_spinlock_t *lock)
-{
- int tmp = 1, busy;
-
- __asm__ __volatile__ (
- " amoswap.w %0, %2, %1\n"
- RISCV_ACQUIRE_BARRIER
- : "=r" (busy), "+A" (lock->lock)
- : "r" (tmp)
- : "memory");
-
- return !busy;
-}
-
-static inline void arch_spin_lock(arch_spinlock_t *lock)
-{
- while (1) {
- if (arch_spin_is_locked(lock))
- continue;
-
- if (arch_spin_trylock(lock))
- break;
- }
-}
-
-/***********************************************************/
-
-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);
-}
+#include <asm/qspinlock.h>
+#include <asm/qrwlock.h>

#endif /* _ASM_RISCV_SPINLOCK_H */
diff --git a/arch/riscv/include/asm/spinlock_types.h b/arch/riscv/include/asm/spinlock_types.h
index f398e7638dd6..d033a973f287 100644
--- a/arch/riscv/include/asm/spinlock_types.h
+++ b/arch/riscv/include/asm/spinlock_types.h
@@ -6,20 +6,11 @@
#ifndef _ASM_RISCV_SPINLOCK_TYPES_H
#define _ASM_RISCV_SPINLOCK_TYPES_H

-#ifndef __LINUX_SPINLOCK_TYPES_H
+#if !defined(__LINUX_SPINLOCK_TYPES_H) && !defined(_ASM_RISCV_SPINLOCK_H)
# error "please don't include this file directly"
#endif

-typedef struct {
- volatile unsigned int lock;
-} arch_spinlock_t;
-
-#define __ARCH_SPIN_LOCK_UNLOCKED { 0 }
-
-typedef struct {
- volatile unsigned int lock;
-} arch_rwlock_t;
-
-#define __ARCH_RW_LOCK_UNLOCKED { 0 }
+#include <asm-generic/qspinlock_types.h>
+#include <asm-generic/qrwlock_types.h>

#endif /* _ASM_RISCV_SPINLOCK_TYPES_H */
--
2.17.1