From: Stefan Kristiansson <stefan.kristians...@saunalahti.fi> Using the l.lwa and l.swa atomic instruction pair. Most openrisc processor cores provide these instructions now. If the instructions are 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: expand to implement all ops suggested by Peter Zijlstra https://lkml.org/lkml/2017/2/20/317] Signed-off-by: Stafford Horne <sho...@gmail.com> --- arch/openrisc/include/asm/Kbuild | 1 - arch/openrisc/include/asm/atomic.h | 126 +++++++++++++++++++++++++++++++++++++ include/asm-generic/atomic.h | 2 + 3 files changed, 128 insertions(+), 1 deletion(-) create mode 100644 arch/openrisc/include/asm/atomic.h diff --git a/arch/openrisc/include/asm/Kbuild b/arch/openrisc/include/asm/Kbuild index 15e6ed5..1cedd63 100644 --- a/arch/openrisc/include/asm/Kbuild +++ b/arch/openrisc/include/asm/Kbuild @@ -1,7 +1,6 @@ header-y += ucontext.h -generic-y += atomic.h generic-y += auxvec.h generic-y += barrier.h generic-y += bitsperlong.h diff --git a/arch/openrisc/include/asm/atomic.h b/arch/openrisc/include/asm/atomic.h new file mode 100644 index 0000000..146e166 --- /dev/null +++ b/arch/openrisc/include/asm/atomic.h @@ -0,0 +1,126 @@ +/* + * 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_ATOMIC_H +#define __ASM_OPENRISC_ATOMIC_H + +#include <linux/types.h> + +/* Atomically perform op with v->counter and i */ +#define ATOMIC_OP(op) \ +static inline void atomic_##op(int i, atomic_t *v) \ +{ \ + int tmp; \ + \ + __asm__ __volatile__( \ + "1: l.lwa %0,0(%1) \n" \ + " l." #op " %0,%0,%2 \n" \ + " l.swa 0(%1),%0 \n" \ + " l.bnf 1b \n" \ + " l.nop \n" \ + : "=&r"(tmp) \ + : "r"(&v->counter), "r"(i) \ + : "cc", "memory"); \ +} + +/* Atomically perform op with v->counter and i, return the result */ +#define ATOMIC_OP_RETURN(op) \ +static inline int atomic_##op##_return(int i, atomic_t *v) \ +{ \ + int tmp; \ + \ + __asm__ __volatile__( \ + "1: l.lwa %0,0(%1) \n" \ + " l." #op " %0,%0,%2 \n" \ + " l.swa 0(%1),%0 \n" \ + " l.bnf 1b \n" \ + " l.nop \n" \ + : "=&r"(tmp) \ + : "r"(&v->counter), "r"(i) \ + : "cc", "memory"); \ + \ + return tmp; \ +} + +/* Atomically perform op with v->counter and i, return orig v->counter */ +#define ATOMIC_FETCH_OP(op) \ +static inline int atomic_fetch_##op(int i, atomic_t *v) \ +{ \ + int tmp, old; \ + \ + __asm__ __volatile__( \ + "1: l.lwa %0,0(%2) \n" \ + " l." #op " %1,%0,%3 \n" \ + " l.swa 0(%2),%1 \n" \ + " l.bnf 1b \n" \ + " l.nop \n" \ + : "=&r"(old), "=&r"(tmp) \ + : "r"(&v->counter), "r"(i) \ + : "cc", "memory"); \ + \ + return old; \ +} + +ATOMIC_OP_RETURN(add) +ATOMIC_OP_RETURN(sub) + +ATOMIC_FETCH_OP(add) +ATOMIC_FETCH_OP(sub) +ATOMIC_FETCH_OP(and) +ATOMIC_FETCH_OP(or) +ATOMIC_FETCH_OP(xor) + +ATOMIC_OP(and) +ATOMIC_OP(or) +ATOMIC_OP(xor) + +#undef ATOMIC_FETCH_OP +#undef ATOMIC_OP_RETURN +#undef ATOMIC_OP + +#define atomic_add_return atomic_add_return +#define atomic_sub_return atomic_sub_return +#define atomic_fetch_add atomic_fetch_add +#define atomic_fetch_sub atomic_fetch_sub +#define atomic_fetch_and atomic_fetch_and +#define atomic_fetch_or atomic_fetch_or +#define atomic_fetch_xor atomic_fetch_xor +#define atomic_and atomic_and +#define atomic_or atomic_or +#define atomic_xor atomic_xor + +/* + * Atomically add a to v->counter as long as v is not already u. + * Returns the original value at v->counter. + * + * This is often used through atomic_inc_not_zero() + */ +static inline int __atomic_add_unless(atomic_t *v, int a, int u) +{ + int old, tmp; + + __asm__ __volatile__( + "1: l.lwa %0, 0(%2) \n" + " l.sfeq %0, %4 \n" + " l.bf 2f \n" + " l.add %1, %0, %3 \n" + " l.swa 0(%2), %1 \n" + " l.bnf 1b \n" + " l.nop \n" + "2: \n" + : "=&r"(old), "=&r" (tmp) + : "r"(&v->counter), "r"(a), "r"(u) + : "cc", "memory"); + + return old; +} +#define __atomic_add_unless __atomic_add_unless + +#include <asm-generic/atomic.h> + +#endif /* __ASM_OPENRISC_ATOMIC_H */ diff --git a/include/asm-generic/atomic.h b/include/asm-generic/atomic.h index 9ed8b98..3f38eb0 100644 --- a/include/asm-generic/atomic.h +++ b/include/asm-generic/atomic.h @@ -223,6 +223,7 @@ static inline void atomic_dec(atomic_t *v) #define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v))) #define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new))) +#ifndef __atomic_add_unless static inline int __atomic_add_unless(atomic_t *v, int a, int u) { int c, old; @@ -231,5 +232,6 @@ static inline int __atomic_add_unless(atomic_t *v, int a, int u) c = old; return c; } +#endif #endif /* __ASM_GENERIC_ATOMIC_H */ -- 2.9.3
