From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 94B4DC433B4 for ; Tue, 13 Apr 2021 16:36:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 77ADC6128E for ; Tue, 13 Apr 2021 16:36:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345913AbhDMQhH (ORCPT ); Tue, 13 Apr 2021 12:37:07 -0400 Received: from pegase1.c-s.fr ([93.17.236.30]:8358 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345371AbhDMQhB (ORCPT ); Tue, 13 Apr 2021 12:37:01 -0400 Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 4FKWTL3l94z9v4hC; Tue, 13 Apr 2021 18:36:38 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id DydKvha3r-0P; Tue, 13 Apr 2021 18:36:38 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 4FKWTL1dSsz9v4h8; Tue, 13 Apr 2021 18:36:38 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id B63518B7AA; Tue, 13 Apr 2021 18:36:39 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id l6EiQIyyQ9dS; Tue, 13 Apr 2021 18:36:39 +0200 (CEST) Received: from [192.168.4.90] (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 5627A8B75F; Tue, 13 Apr 2021 18:36:39 +0200 (CEST) Subject: Re: [PATCH v1 2/2] powerpc/atomics: Use immediate operand when possible To: Segher Boessenkool Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org References: <09da6fec57792d6559d1ea64e00be9870b02dab4.1617896018.git.christophe.leroy@csgroup.eu> <9f50b5fadeb090553e5c2fae025052d04d52f3c7.1617896018.git.christophe.leroy@csgroup.eu> <20210412220821.GN26583@gate.crashing.org> From: Christophe Leroy Message-ID: <063ca819-1276-8deb-0d9b-ea6ec33f9a98@csgroup.eu> Date: Tue, 13 Apr 2021 18:36:04 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.9.1 MIME-Version: 1.0 In-Reply-To: <20210412220821.GN26583@gate.crashing.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 13/04/2021 à 00:08, Segher Boessenkool a écrit : > Hi! > > On Thu, Apr 08, 2021 at 03:33:45PM +0000, Christophe Leroy wrote: >> +#define ATOMIC_OP(op, asm_op, dot, sign) \ >> static __inline__ void atomic_##op(int a, atomic_t *v) \ >> { \ >> int t; \ >> \ >> __asm__ __volatile__( \ >> "1: lwarx %0,0,%3 # atomic_" #op "\n" \ >> - #asm_op " %0,%2,%0\n" \ >> + #asm_op "%I2" dot " %0,%0,%2\n" \ >> " stwcx. %0,0,%3 \n" \ >> " bne- 1b\n" \ >> - : "=&r" (t), "+m" (v->counter) \ >> - : "r" (a), "r" (&v->counter) \ >> + : "=&b" (t), "+m" (v->counter) \ >> + : "r"#sign (a), "r" (&v->counter) \ >> : "cc"); \ >> } \ > > You need "b" (instead of "r") only for "addi". You can use "addic" > instead, which clobbers XER[CA], but *all* inline asm does, so that is > not a downside here (it is also not slower on any CPU that matters). > >> @@ -238,14 +238,14 @@ static __inline__ int atomic_fetch_add_unless(atomic_t *v, int a, int u) >> "1: lwarx %0,0,%1 # atomic_fetch_add_unless\n\ >> cmpw 0,%0,%3 \n\ >> beq 2f \n\ >> - add %0,%2,%0 \n" >> + add%I2 %0,%0,%2 \n" >> " stwcx. %0,0,%1 \n\ >> bne- 1b \n" >> PPC_ATOMIC_EXIT_BARRIER >> -" subf %0,%2,%0 \n\ >> +" sub%I2 %0,%0,%2 \n\ >> 2:" >> - : "=&r" (t) >> - : "r" (&v->counter), "r" (a), "r" (u) >> + : "=&b" (t) >> + : "r" (&v->counter), "rI" (a), "r" (u) >> : "cc", "memory"); > > Same here. Yes, I thought about addic, I didn't find an early solution because I forgot the matching 'addc'. Now with the couple addc/addic it works well. Thanks > > Nice patches! > > Acked-by: Segher Boessenkool > Christophe