From 45e15c1a375ea380d55880be2f8182cb737b60ed Mon Sep 17 00:00:00 2001 From: Guo Ren Date: Sat, 23 Jul 2022 21:32:34 -0400 Subject: [PATCH] csky: Add qspinlock support Enable qspinlock by the requirements mentioned in a8ad07e5240c9 ("asm-generic: qspinlock: Indicate the use of mixed-size atomics"). C-SKY only has "ldex/stex" for all atomic operations. So csky give a strong forward guarantee for "ldex/stex." That means when ldex grabbed the cache line into $L1, it would block other cores from snooping the address with several cycles. The atomic_fetch_add & xchg16 has the same forward guarantee level in C-SKY. Qspinlock has better code size and performance in a fast path. Signed-off-by: Guo Ren Signed-off-by: Guo Ren --- arch/csky/Kconfig | 1 + arch/csky/include/asm/Kbuild | 4 ++-- arch/csky/include/asm/cmpxchg.h | 20 ++++++++++++++++++++ arch/csky/include/asm/spinlock.h | 12 ++++++++++++ arch/csky/include/asm/spinlock_types.h | 9 +++++++++ 5 files changed, 44 insertions(+), 2 deletions(-) create mode 100644 arch/csky/include/asm/spinlock.h create mode 100644 arch/csky/include/asm/spinlock_types.h diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig index 41d7d61..333def1 100644 --- a/arch/csky/Kconfig +++ b/arch/csky/Kconfig @@ -8,6 +8,7 @@ config CSKY select ARCH_HAS_SYNC_DMA_FOR_DEVICE select ARCH_USE_BUILTIN_BSWAP select ARCH_USE_QUEUED_RWLOCKS + select ARCH_USE_QUEUED_SPINLOCKS select ARCH_WANT_FRAME_POINTERS if !CPU_CK610 && $(cc-option,-mbacktrace) select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT select COMMON_CLK diff --git a/arch/csky/include/asm/Kbuild b/arch/csky/include/asm/Kbuild index 103207a..1117c28 100644 --- a/arch/csky/include/asm/Kbuild +++ b/arch/csky/include/asm/Kbuild @@ -3,10 +3,10 @@ generic-y += asm-offsets.h generic-y += extable.h generic-y += gpio.h generic-y += kvm_para.h -generic-y += spinlock.h -generic-y += spinlock_types.h +generic-y += mcs_spinlock.h generic-y += qrwlock.h generic-y += qrwlock_types.h +generic-y += qspinlock.h generic-y += parport.h generic-y += user.h generic-y += vmlinux.lds.h diff --git a/arch/csky/include/asm/cmpxchg.h b/arch/csky/include/asm/cmpxchg.h index 5b8facc..5f693fa 100644 --- a/arch/csky/include/asm/cmpxchg.h +++ b/arch/csky/include/asm/cmpxchg.h @@ -15,6 +15,26 @@ extern void __bad_xchg(void); __typeof__(*(ptr)) __ret; \ unsigned long tmp; \ switch (size) { \ + case 2: { \ + u32 ret; \ + u32 shif = ((ulong)__ptr & 2) ? 16 : 0; \ + u32 mask = 0xffff << shif; \ + __ptr = (__typeof__(ptr))((ulong)__ptr & ~2); \ + __asm__ __volatile__ ( \ + "1: ldex.w %0, (%4)\n" \ + " and %1, %0, %2\n" \ + " or %1, %1, %3\n" \ + " stex.w %1, (%4)\n" \ + " bez %1, 1b\n" \ + : "=&r" (ret), "=&r" (tmp) \ + : "r" (~mask), \ + "r" ((u32)__new << shif), \ + "r" (__ptr) \ + : "memory"); \ + __ret = (__typeof__(*(ptr))) \ + ((ret & mask) >> shif); \ + break; \ + } \ case 4: \ asm volatile ( \ "1: ldex.w %0, (%3) \n" \ diff --git a/arch/csky/include/asm/spinlock.h b/arch/csky/include/asm/spinlock.h new file mode 100644 index 0000000..83a2005 --- /dev/null +++ b/arch/csky/include/asm/spinlock.h @@ -0,0 +1,12 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef __ASM_CSKY_SPINLOCK_H +#define __ASM_CSKY_SPINLOCK_H + +#include +#include + +/* See include/linux/spinlock.h */ +#define smp_mb__after_spinlock() smp_mb() + +#endif /* __ASM_CSKY_SPINLOCK_H */ diff --git a/arch/csky/include/asm/spinlock_types.h b/arch/csky/include/asm/spinlock_types.h new file mode 100644 index 0000000..75bdf3a --- /dev/null +++ b/arch/csky/include/asm/spinlock_types.h @@ -0,0 +1,9 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef __ASM_CSKY_SPINLOCK_TYPES_H +#define __ASM_CSKY_SPINLOCK_TYPES_H + +#include +#include + +#endif /* __ASM_CSKY_SPINLOCK_TYPES_H */ -- 2.7.4