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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 888CFEDE99C for ; Thu, 14 Sep 2023 09:37:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237134AbjINJh4 (ORCPT ); Thu, 14 Sep 2023 05:37:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45836 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237096AbjINJhy (ORCPT ); Thu, 14 Sep 2023 05:37:54 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id C8EA81BFF for ; Thu, 14 Sep 2023 02:37:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1694684222; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=8vQlQADn2LNqOGAlsXmaezeqHZMFdsyRwPKTLWRd854=; b=iwh8AcsFFAWAM7vPuTOBygpwDPWqjO8YVdOhkwkgRdhfH2xwkEYJ/Fmz6BTj1HEg2Zsu4w KMx7IL32s/lcF7+R1N9Aq6VEu4QBN5f+QXel7dmhkfmyCtvHkg9FnJ4JUzWSfCcyKGpdLV uGDrif9w7OSlLfncVIRaALjXvzabUww= Received: from mail-oi1-f197.google.com (mail-oi1-f197.google.com [209.85.167.197]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-256-9O-J9wqJOaGm8qF7uU6lsA-1; Thu, 14 Sep 2023 05:37:00 -0400 X-MC-Unique: 9O-J9wqJOaGm8qF7uU6lsA-1 Received: by mail-oi1-f197.google.com with SMTP id 5614622812f47-3aa1254fb00so1059310b6e.1 for ; Thu, 14 Sep 2023 02:37:00 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1694684219; x=1695289019; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=8vQlQADn2LNqOGAlsXmaezeqHZMFdsyRwPKTLWRd854=; b=YsTAPfFZEZEc1Bi6Y15RmcJNeX4+1kNJffNXSXaSW8h5wpw4tC+gMuaLEPwY/HX7zI sWngANETnCW64cSXFqpHLk7SMFuGheD9XKFGAo9qF8Nx5g0qA7OyUTO1Y+DonKI2TRyd 8nsCGv0qkbwB30Qhgc72Wmk/ZhnKHvlca99UFGaY3428f6M/AU4H2Ks37YnVUNaxlZkP cuhMFoLTONuXG4WLmbxuOYptF/b8FVTBYAdYiZl6z0VLm0mfIhSprJILWgO+NX2XW7Ml ZA1LLtJZSX34ik6BIOqSaonZc4Y5xfgffuGdJZFsrvnJzkvDEDrznbAs87fXBIkONwPi wMEw== X-Gm-Message-State: AOJu0YxQoS0rZ4fjQkhsePIGzACxjpKkM0fPI3qZvFufWlzp/TdAanev Faxm6omFPeKtNas2noeArssJjkwGuXelkNpDoWroS2epbWOAPqxj6kchMLFkwFpObBvDkCBN823 xYUXlfntbevy13MJ9HMKJhg== X-Received: by 2002:a05:6808:bd4:b0:3a3:7a28:f841 with SMTP id o20-20020a0568080bd400b003a37a28f841mr6256011oik.41.1694684219286; Thu, 14 Sep 2023 02:36:59 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEOYB9XBC6PVpc7f+a0f60gNl1NFed8atTc8/uEab+FTz4RvHJ//hpWsS4nDqiqEtsGdQd5ag== X-Received: by 2002:a05:6808:bd4:b0:3a3:7a28:f841 with SMTP id o20-20020a0568080bd400b003a37a28f841mr6255987oik.41.1694684219072; Thu, 14 Sep 2023 02:36:59 -0700 (PDT) Received: from redhat.com ([2804:1b3:a803:4ff9:7c29:fe41:6aa7:43df]) by smtp.gmail.com with ESMTPSA id n11-20020a9d4d0b000000b006b96a4287d4sm495055otf.5.2023.09.14.02.36.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Sep 2023 02:36:58 -0700 (PDT) Date: Thu, 14 Sep 2023 06:36:49 -0300 From: Leonardo Bras To: guoren@kernel.org Cc: paul.walmsley@sifive.com, anup@brainfault.org, peterz@infradead.org, mingo@redhat.com, will@kernel.org, palmer@rivosinc.com, longman@redhat.com, boqun.feng@gmail.com, tglx@linutronix.de, paulmck@kernel.org, rostedt@goodmis.org, rdunlap@infradead.org, catalin.marinas@arm.com, conor.dooley@microchip.com, xiaoguang.xing@sophgo.com, bjorn@rivosinc.com, alexghiti@rivosinc.com, keescook@chromium.org, greentime.hu@sifive.com, ajones@ventanamicro.com, jszhang@kernel.org, wefu@redhat.com, wuwei2016@iscas.ac.cn, linux-arch@vger.kernel.org, linux-riscv@lists.infradead.org, linux-doc@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-csky@vger.kernel.org, Guo Ren Subject: Re: [PATCH V11 10/17] riscv: qspinlock: errata: Enable qspinlock for T-HEAD processors Message-ID: References: <20230910082911.3378782-1-guoren@kernel.org> <20230910082911.3378782-11-guoren@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230910082911.3378782-11-guoren@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-csky@vger.kernel.org On Sun, Sep 10, 2023 at 04:29:04AM -0400, guoren@kernel.org wrote: > From: Guo Ren > > According to qspinlock requirements, RISC-V gives out a weak LR/SC > forward progress guarantee which does not satisfy qspinlock. But > many vendors could produce stronger forward guarantee LR/SC to > ensure the xchg_tail could be finished in time on any kind of > hart. T-HEAD is the vendor nit: "a vendor" > which implements strong forward > guarantee LR/SC instruction pairs, so enable qspinlock for T-HEAD > with errata init help. > > Signed-off-by: Guo Ren > Signed-off-by: Guo Ren > --- > arch/riscv/errata/thead/errata.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/arch/riscv/errata/thead/errata.c b/arch/riscv/errata/thead/errata.c > index 751eb5a7f614..0df6a67302c0 100644 > --- a/arch/riscv/errata/thead/errata.c > +++ b/arch/riscv/errata/thead/errata.c > @@ -86,6 +86,13 @@ static bool errata_probe_write_once(unsigned int stage, > return false; > } > > +extern bool enable_qspinlock_key; Oh, now I understand why it was not static before. :) > +static void errata_probe_qspinlock(unsigned int stage) > +{ > + if (stage == RISCV_ALTERNATIVES_BOOT) > + enable_qspinlock_key = true; > +} > + > static u32 thead_errata_probe(unsigned int stage, > unsigned long archid, unsigned long impid) > { > @@ -103,6 +110,8 @@ static u32 thead_errata_probe(unsigned int stage, > if (errata_probe_write_once(stage, archid, impid)) > cpu_req_errata |= BIT(ERRATA_THEAD_WRITE_ONCE); > > + errata_probe_qspinlock(stage); > + > return cpu_req_errata; > } > So, if THEAD then enable qspinlock(). LGTM: Reviewed-by: Leonardo Bras > -- > 2.36.1 >