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=-8.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 5A07EC43613 for ; Mon, 24 Jun 2019 05:44:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 24905208CA for ; Mon, 24 Jun 2019 05:44:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Ox0Bj2s2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726443AbfFXFoj (ORCPT ); Mon, 24 Jun 2019 01:44:39 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:37040 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726223AbfFXFnv (ORCPT ); Mon, 24 Jun 2019 01:43:51 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From :Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=43pRHKdJKqNssrr4/Vc0cDK/nlhOlcebDC3ttvLu+nk=; b=Ox0Bj2s2AYtMiNqOyzVUJu1aca 4Zw5sJu947Gj5rs0jUIlbbOtlbwYiuHZ0nJ1wtQi79umOkWFdlOji03dK+QH22LmwJp2C8vJ56/Fw VBYObyjWlQcJ9h5SQj6t76j0JD5TudW+arpOJd2w7RxIDG8pwuO4dR1jb3JpSDfRzc7ZczKYWm7vh QI2c2xxg9ZuRIDvDgzexiDXDbZSYqdKgNNN3aPwHwGLG857aQEXAdzB2Nf4gvK+YbgR5Imuqbwebr zBivLC6z+ob0BD9JpbwnxUy0vPPLYKipdDiBzZ5jLr7Jy5pym/AnznE86d12FYY1jmZQrC/xeH+IC s5lNwFPQ==; Received: from 213-225-6-159.nat.highway.a1.net ([213.225.6.159] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1hfHld-0006Xj-5S; Mon, 24 Jun 2019 05:43:49 +0000 From: Christoph Hellwig To: Palmer Dabbelt , Paul Walmsley Cc: Damien Le Moal , linux-riscv@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Damien Le Moal Subject: [PATCH 10/17] riscv: read the hart ID from mhartid on boot Date: Mon, 24 Jun 2019 07:43:04 +0200 Message-Id: <20190624054311.30256-11-hch@lst.de> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190624054311.30256-1-hch@lst.de> References: <20190624054311.30256-1-hch@lst.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Damien Le Moal When in M-Mode, we can use the mhartid CSR to get the ID of the running HART. Doing so, direct M-Mode boot without firmware is possible. Signed-off-by: Damien Le Moal Signed-off-by: Christoph Hellwig --- arch/riscv/kernel/head.S | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index e5fa5481aa99..a4c170e41a34 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -18,6 +18,14 @@ ENTRY(_start) csrw CSR_XIE, zero csrw CSR_XIP, zero +#ifdef CONFIG_M_MODE + /* + * The hartid in a0 is expected later on, and we have no firmware + * to hand it to us. + */ + csrr a0, mhartid +#endif + /* Load the global pointer */ .option push .option norelax -- 2.20.1