From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f41.google.com (mail-ed1-f41.google.com [209.85.208.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2E5CC3FB3D; Wed, 10 Jan 2024 22:34:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="di8EUN5x" Received: by mail-ed1-f41.google.com with SMTP id 4fb4d7f45d1cf-5582796b85bso1904842a12.2; Wed, 10 Jan 2024 14:34:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1704926077; x=1705530877; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=amcLJqpm9QgZcs/rA3fHaBICgItRkDbfb+YSi8eii8Y=; b=di8EUN5xGpXQM9TeXLhjsRKaXAVeJLwTsyIiIviHtWX+FUU1R3Q8gtm9qf9oNAenZa Bz05gXi48AxC1WhDufga9gxuL2SVBonnd9EWc6Q1/JUfdaZgt81tlsAoX5McEWVTLjK7 5V8cwgnkVYcmBwgiwZgZUU8zhyHvw+VLpS3l8/NqMuVpBC8/DWTAgS79ffn3TgIGmx0x gWWK8+eS1HcpLPn4B0jH0dcpG9NisylDvB91MgWiX0RD99Nua6vB2yv94MLcO2va80Uu cUX4Tld393REhHgLsKhwHWmsbM3G5FS8q2vwmSlZQtZR6DiJ+T63KXLHXU9soeT9VSYA zbHQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1704926077; x=1705530877; 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=amcLJqpm9QgZcs/rA3fHaBICgItRkDbfb+YSi8eii8Y=; b=YHCEJCYD8kdBO+oryh8eVTetdXimh5WivRx4VrPW4WzG787k4YpOqDebR7HGJdLR29 WClWIIAiaYRpXYnFQ5o9yXtRA8RT+qsSAInwaeysyZ1H9tVRSaXkYe/bU0WKz7oyXhU2 eg2sLMaFAPmNjVsBwfbZS1eYLWbsUXlSnB1AKzQ9PYsOyeRWZTL0DoH240O4fZEO6vJV GE5alOt0d9OP9F9wrohxcDD607p/FAfADz/XSTqQT41DLScr07TjNF5HiNdAzXdpscKx tcy8qeu7EXI+1zK6vILIvgnTxEPU4XO36wluKfGeBwa1lox/NAIeQqVxptPwOnvmLP5J lchw== X-Gm-Message-State: AOJu0YxVGqr7mboj+nLFg8nwXA8niUbAm2Izufjr799fiOPG+zVoPfte p/ujIr1IbaSknboAcyZ1DhP7mwTRLaYAmQ== X-Google-Smtp-Source: AGHT+IEtgolnaN71uAvu7gHsKkVAwem27SKnfOVHefMhJhoKWSuu6zzvffBkF/WaXMgWqgu7v8lEoQ== X-Received: by 2002:a17:906:1e:b0:a25:1acc:ff45 with SMTP id 30-20020a170906001e00b00a251accff45mr115159eja.143.1704926077219; Wed, 10 Jan 2024 14:34:37 -0800 (PST) Received: from andrea ([31.189.29.12]) by smtp.gmail.com with ESMTPSA id kt10-20020a170906aaca00b00a27a6d59045sm2493815ejb.217.2024.01.10.14.34.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 10 Jan 2024 14:34:36 -0800 (PST) Date: Wed, 10 Jan 2024 23:34:32 +0100 From: Andrea Parri To: Stefan O'Rear Cc: paul.walmsley@sifive.com, Palmer Dabbelt , Albert Ou , mathieu.desnoyers@efficios.com, paulmck@kernel.org, Jonathan Corbet , mmaas@google.com, Hans Boehm , striker@us.ibm.com, charlie@rivosinc.com, rehn@rivosinc.com, linux-riscv@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 4/4] membarrier: riscv: Provide core serializing command Message-ID: References: <20240110145533.60234-1-parri.andrea@gmail.com> <20240110145533.60234-5-parri.andrea@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Hi Stefan, > "core serialization" is a meaningless sequence of words for RISC-V users, The expression is inherited from MEMBARRIER(2). Quoting from the RFC discussion (cf. [3] in the cover letter), "RISC-V does not have "core serializing instructions", meaning that there is no occurence of such a term in the RISC-V ISA. The discussion and git history about the SYNC_CORE command suggested the implementation below: a FENCE.I instruction [...]" > The feature seems useful, but it should document what it does using > terminology actually used in the RISC-V specifications. In _current RISC-V parlance, it's pretty clear: we are doing FENCE.I. As Palmer and others mentioned in the RFC, there're proposals for ISA extensions aiming to "replace" FENCE.I, but those are still WIP. (*) Andrea (*) https://github.com/riscv/riscv-j-extension