From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753369AbcEaKir (ORCPT ); Tue, 31 May 2016 06:38:47 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:43371 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751657AbcEaK3v (ORCPT ); Tue, 31 May 2016 06:29:51 -0400 Message-Id: <20160531102642.526865975@infradead.org> User-Agent: quilt/0.61-1 Date: Tue, 31 May 2016 12:19:42 +0200 From: Peter Zijlstra To: torvalds@linux-foundation.org, mingo@kernel.org, tglx@linutronix.de, will.deacon@arm.com, paulmck@linux.vnet.ibm.com, boqun.feng@gmail.com, waiman.long@hpe.com, fweisbec@gmail.com Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, rth@twiddle.net, vgupta@synopsys.com, linux@arm.linux.org.uk, egtvedt@samfundet.no, realmz6@gmail.com, ysato@users.sourceforge.jp, rkuo@codeaurora.org, tony.luck@intel.com, geert@linux-m68k.org, james.hogan@imgtec.com, ralf@linux-mips.org, dhowells@redhat.com, jejb@parisc-linux.org, mpe@ellerman.id.au, schwidefsky@de.ibm.com, dalias@libc.org, davem@davemloft.net, cmetcalf@mellanox.com, jcmvbkbc@gmail.com, arnd@arndb.de, peterz@infradead.org, dbueso@suse.de, fengguang.wu@intel.com Subject: [PATCH -v2 17/33] locking,mn10300: Implement atomic_fetch_{add,sub,and,or,xor}() References: <20160531101925.702692792@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline; filename=peterz-atomic-fetch-mn10300.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Implement FETCH-OP atomic primitives, these are very similar to the existing OP-RETURN primitives we already have, except they return the value of the atomic variable _before_ modification. This is especially useful for irreversible operations -- such as bitops (because it becomes impossible to reconstruct the state prior to modification). Signed-off-by: Peter Zijlstra (Intel) --- arch/mn10300/include/asm/atomic.h | 35 +++++++++++++++++++++++++++++++---- 1 file changed, 31 insertions(+), 4 deletions(-) --- a/arch/mn10300/include/asm/atomic.h +++ b/arch/mn10300/include/asm/atomic.h @@ -84,16 +84,43 @@ static inline int atomic_##op##_return(i return retval; \ } -#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op) +#define ATOMIC_FETCH_OP(op) \ +static inline int atomic_fetch_##op(int i, atomic_t *v) \ +{ \ + int retval, status; \ + \ + asm volatile( \ + "1: mov %4,(_AAR,%3) \n" \ + " mov (_ADR,%3),%1 \n" \ + " mov %1,%0 \n" \ + " " #op " %5,%0 \n" \ + " mov %0,(_ADR,%3) \n" \ + " mov (_ADR,%3),%0 \n" /* flush */ \ + " mov (_ASR,%3),%0 \n" \ + " or %0,%0 \n" \ + " bne 1b \n" \ + : "=&r"(status), "=&r"(retval), "=m"(v->counter) \ + : "a"(ATOMIC_OPS_BASE_ADDR), "r"(&v->counter), "r"(i) \ + : "memory", "cc"); \ + return retval; \ +} + +#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op) ATOMIC_FETCH_OP(op) ATOMIC_OPS(add) ATOMIC_OPS(sub) -ATOMIC_OP(and) -ATOMIC_OP(or) -ATOMIC_OP(xor) +#undef ATOMIC_OPS +#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op) + +#define atomic_fetch_or atomic_fetch_or + +ATOMIC_OPS(and) +ATOMIC_OPS(or) +ATOMIC_OPS(xor) #undef ATOMIC_OPS +#undef ATOMIC_FETCH_OP #undef ATOMIC_OP_RETURN #undef ATOMIC_OP