On Fri, 18 Mar 2022 01:34:21 PDT (-0700), guoren@xxxxxxxxxx wrote:
From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
There is no benefit from custom implementation for ticket-spinlock,
so move to generic ticket-spinlock for easy maintenance.
Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxxx>
Thanks, one less port to look at ;)
Looks like there were a few comments on the v1, and I wasn't going to
target this at the upcoming merge window anyway because I wanted to give
the various RISC-V vendors time to test stuff. LMK if you want me to
add this to the others, but I was planning on posting a stable tag
either way so no big deal on my end.
---
arch/csky/include/asm/Kbuild | 2 +
arch/csky/include/asm/spinlock.h | 82 +-------------------------
arch/csky/include/asm/spinlock_types.h | 20 +------
3 files changed, 4 insertions(+), 100 deletions(-)
diff --git a/arch/csky/include/asm/Kbuild b/arch/csky/include/asm/Kbuild
index 904a18a818be..d94434288c31 100644
--- a/arch/csky/include/asm/Kbuild
+++ b/arch/csky/include/asm/Kbuild
@@ -3,6 +3,8 @@ generic-y += asm-offsets.h
generic-y += extable.h
generic-y += gpio.h
generic-y += kvm_para.h
+generic-y += ticket-lock.h
+generic-y += ticket-lock-types.h
generic-y += qrwlock.h
generic-y += user.h
generic-y += vmlinux.lds.h
diff --git a/arch/csky/include/asm/spinlock.h b/arch/csky/include/asm/spinlock.h
index 69f5aa249c5f..8bc179ba0d8d 100644
--- a/arch/csky/include/asm/spinlock.h
+++ b/arch/csky/include/asm/spinlock.h
@@ -3,87 +3,7 @@
#ifndef __ASM_CSKY_SPINLOCK_H
#define __ASM_CSKY_SPINLOCK_H
-#include <linux/spinlock_types.h>
-#include <asm/barrier.h>
-
-/*
- * Ticket-based spin-locking.
- */
-static inline void arch_spin_lock(arch_spinlock_t *lock)
-{
- arch_spinlock_t lockval;
- u32 ticket_next = 1 << TICKET_NEXT;
- u32 *p = &lock->lock;
- u32 tmp;
-
- asm volatile (
- "1: ldex.w %0, (%2) \n"
- " mov %1, %0 \n"
- " add %0, %3 \n"
- " stex.w %0, (%2) \n"
- " bez %0, 1b \n"
- : "=&r" (tmp), "=&r" (lockval)
- : "r"(p), "r"(ticket_next)
- : "cc");
-
- while (lockval.tickets.next != lockval.tickets.owner)
- lockval.tickets.owner = READ_ONCE(lock->tickets.owner);
-
- smp_mb();
-}
-
-static inline int arch_spin_trylock(arch_spinlock_t *lock)
-{
- u32 tmp, contended, res;
- u32 ticket_next = 1 << TICKET_NEXT;
- u32 *p = &lock->lock;
-
- do {
- asm volatile (
- " ldex.w %0, (%3) \n"
- " movi %2, 1 \n"
- " rotli %1, %0, 16 \n"
- " cmpne %1, %0 \n"
- " bt 1f \n"
- " movi %2, 0 \n"
- " add %0, %0, %4 \n"
- " stex.w %0, (%3) \n"
- "1: \n"
- : "=&r" (res), "=&r" (tmp), "=&r" (contended)
- : "r"(p), "r"(ticket_next)
- : "cc");
- } while (!res);
-
- if (!contended)
- smp_mb();
-
- return !contended;
-}
-
-static inline void arch_spin_unlock(arch_spinlock_t *lock)
-{
- smp_mb();
- WRITE_ONCE(lock->tickets.owner, lock->tickets.owner + 1);
-}
-
-static inline int arch_spin_value_unlocked(arch_spinlock_t lock)
-{
- return lock.tickets.owner == lock.tickets.next;
-}
-
-static inline int arch_spin_is_locked(arch_spinlock_t *lock)
-{
- return !arch_spin_value_unlocked(READ_ONCE(*lock));
-}
-
-static inline int arch_spin_is_contended(arch_spinlock_t *lock)
-{
- struct __raw_tickets tickets = READ_ONCE(lock->tickets);
-
- return (tickets.next - tickets.owner) > 1;
-}
-#define arch_spin_is_contended arch_spin_is_contended
-
+#include <asm/ticket-lock.h>
#include <asm/qrwlock.h>
#endif /* __ASM_CSKY_SPINLOCK_H */
diff --git a/arch/csky/include/asm/spinlock_types.h b/arch/csky/include/asm/spinlock_types.h
index db87a12c3827..0bb7f6022a3b 100644
--- a/arch/csky/include/asm/spinlock_types.h
+++ b/arch/csky/include/asm/spinlock_types.h
@@ -3,25 +3,7 @@
#ifndef __ASM_CSKY_SPINLOCK_TYPES_H
#define __ASM_CSKY_SPINLOCK_TYPES_H
-#ifndef __LINUX_SPINLOCK_TYPES_RAW_H
-# error "please don't include this file directly"
-#endif
-
-#define TICKET_NEXT 16
-
-typedef struct {
- union {
- u32 lock;
- struct __raw_tickets {
- /* little endian */
- u16 owner;
- u16 next;
- } tickets;
- };
-} arch_spinlock_t;
-
-#define __ARCH_SPIN_LOCK_UNLOCKED { { 0 } }
-
+#include <asm/ticket-lock-types.h>
#include <asm-generic/qrwlock_types.h>
#endif /* __ASM_CSKY_SPINLOCK_TYPES_H */
