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=-8.8 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,URIBL_BLOCKED,URIBL_SBL,URIBL_SBL_A,USER_AGENT_GIT 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 00DCFCA9EC0 for ; Mon, 28 Oct 2019 12:11:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C2E1121744 for ; Mon, 28 Oct 2019 12:11:15 +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="ucY8lKKD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388900AbfJ1MLO (ORCPT ); Mon, 28 Oct 2019 08:11:14 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:52498 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388869AbfJ1MLL (ORCPT ); Mon, 28 Oct 2019 08:11:11 -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=6VagoDFQgXNCA+UAJQ0E/1j0Ng3n2+jdyEXvkHZ2HZ8=; b=ucY8lKKD6GWPBKd71bQTaCGMJV NmfYWxK4apeC0QOYw5iAXiuVjrQtlAq7F8AXUe6cqGwFpvmyAUcgn4cbK3rI4acMXeRTw3LPV7HEH oWhT/dQgkEKF2U9ubme6elydUkFPWtAPYZlWUvtmOr5tbR7cFxCoYAkx8Z+QNsZ7chB8n4QsTfAHS A3DLPjRx0+q8KwXXcv4AlclQtoTFs3IlAsc11VAdiXdWhXGHZ3fD9vJCXALF8p6lK2H6RigK0T+f0 AHcgrvGsQEP07Pv4gJuwV4IHm/JKLMiwIp59oL0pY+2vjxFq93sJ00VlIaamRz5ltm8Zw42ZxUN7h xoQM31Iw==; Received: from [2001:4bb8:18c:c7d:c70:4a89:bc61:2] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1iP3rY-00074U-Tg; Mon, 28 Oct 2019 12:11:09 +0000 From: Christoph Hellwig To: Palmer Dabbelt , Paul Walmsley Cc: Damien Le Moal , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Anup Patel , Atish Patra Subject: [PATCH 08/12] riscv: read the hart ID from mhartid on boot Date: Mon, 28 Oct 2019 13:10:39 +0100 Message-Id: <20191028121043.22934-9-hch@lst.de> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191028121043.22934-1-hch@lst.de> References: <20191028121043.22934-1-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 Reviewed-by: Anup Patel Reviewed-by: Atish Patra Signed-off-by: Christoph Hellwig --- arch/riscv/include/asm/csr.h | 1 + arch/riscv/kernel/head.S | 8 ++++++++ 2 files changed, 9 insertions(+) diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h index 0ab642811028..318192c66fd8 100644 --- a/arch/riscv/include/asm/csr.h +++ b/arch/riscv/include/asm/csr.h @@ -99,6 +99,7 @@ #define CSR_MCAUSE 0x342 #define CSR_MTVAL 0x343 #define CSR_MIP 0x344 +#define CSR_MHARTID 0xf14 #ifdef CONFIG_RISCV_M_MODE # define CSR_STATUS CSR_MSTATUS diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index 5cfd2c582945..fc9973086946 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -50,6 +50,14 @@ _start_kernel: csrw CSR_IE, zero csrw CSR_IP, zero +#ifdef CONFIG_RISCV_M_MODE + /* + * The hartid in a0 is expected later on, and we have no firmware + * to hand it to us. + */ + csrr a0, CSR_MHARTID +#endif + /* Load the global pointer */ .option push .option norelax -- 2.20.1