From: Stefan Kristiansson <stefan.kristians...@saunalahti.fi> Optimized version that make use of the l.lwa and l.swa atomic instruction pair. Most openrisc cores provide these instructions now, if not available emulation is provided.
Cc: Peter Zijlstra <pet...@infradead.org> Signed-off-by: Stefan Kristiansson <stefan.kristians...@saunalahti.fi> [sho...@gmail.com: remove OPENRISC_HAVE_INST_LWA_SWA config suggesed by Alan Cox https://lkml.org/lkml/2014/7/23/666] [sho...@gmail.com: fixed unused calculated value compiler warning in define cmpxchg] Signed-off-by: Stafford Horne <sho...@gmail.com> --- arch/openrisc/include/asm/Kbuild | 2 - arch/openrisc/include/asm/cmpxchg.h | 83 +++++++++++++++++++++++++++++++++++++ 2 files changed, 83 insertions(+), 2 deletions(-) create mode 100644 arch/openrisc/include/asm/cmpxchg.h diff --git a/arch/openrisc/include/asm/Kbuild b/arch/openrisc/include/asm/Kbuild index 6dd177d..15e6ed5 100644 --- a/arch/openrisc/include/asm/Kbuild +++ b/arch/openrisc/include/asm/Kbuild @@ -10,8 +10,6 @@ generic-y += bugs.h generic-y += cacheflush.h generic-y += checksum.h generic-y += clkdev.h -generic-y += cmpxchg-local.h -generic-y += cmpxchg.h generic-y += cputime.h generic-y += current.h generic-y += device.h diff --git a/arch/openrisc/include/asm/cmpxchg.h b/arch/openrisc/include/asm/cmpxchg.h new file mode 100644 index 0000000..5fcb9ac --- /dev/null +++ b/arch/openrisc/include/asm/cmpxchg.h @@ -0,0 +1,83 @@ +/* + * Copyright (C) 2014 Stefan Kristiansson <stefan.kristians...@saunalahti.fi> + * + * This file is licensed under the terms of the GNU General Public License + * version 2. This program is licensed "as is" without any warranty of any + * kind, whether express or implied. + */ + +#ifndef __ASM_OPENRISC_CMPXCHG_H +#define __ASM_OPENRISC_CMPXCHG_H + +#include <linux/types.h> + +/* + * This function doesn't exist, so you'll get a linker error + * if something tries to do an invalid cmpxchg(). + */ +extern void __cmpxchg_called_with_bad_pointer(void); + +#define __HAVE_ARCH_CMPXCHG 1 + +static inline unsigned long +__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size) +{ + if (size != 4) { + __cmpxchg_called_with_bad_pointer(); + return old; + } + + __asm__ __volatile__( + "1: l.lwa %0, 0(%1) \n" + " l.sfeq %0, %2 \n" + " l.bnf 2f \n" + " l.nop \n" + " l.swa 0(%1), %3 \n" + " l.bnf 1b \n" + " l.nop \n" + "2: \n" + : "=&r"(old) + : "r"(ptr), "r"(old), "r"(new) + : "cc", "memory"); + + return old; +} + +#define cmpxchg(ptr, o, n) \ + ({ \ + (__typeof__(*(ptr))) __cmpxchg((ptr), \ + (unsigned long)(o), \ + (unsigned long)(n), \ + sizeof(*(ptr))); \ + }) + +/* + * This function doesn't exist, so you'll get a linker error if + * something tries to do an invalidly-sized xchg(). + */ +extern void __xchg_called_with_bad_pointer(void); + +static inline unsigned long __xchg(unsigned long val, volatile void *ptr, + int size) +{ + if (size != 4) { + __xchg_called_with_bad_pointer(); + return val; + } + + __asm__ __volatile__( + "1: l.lwa %0, 0(%1) \n" + " l.swa 0(%1), %2 \n" + " l.bnf 1b \n" + " l.nop \n" + : "=&r"(val) + : "r"(ptr), "r"(val) + : "cc", "memory"); + + return val; +} + +#define xchg(ptr, with) \ + ((typeof(*(ptr)))__xchg((unsigned long)(with), (ptr), sizeof(*(ptr)))) + +#endif /* __ASM_OPENRISC_CMPXCHG_H */ -- 2.9.3
