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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 6ECB4C433FF for ; Tue, 13 Aug 2019 15:48:15 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3E94D2085A for ; Tue, 13 Aug 2019 15:48:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="HTJ7O597" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3E94D2085A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-riscv-bounces+infradead-linux-riscv=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=c6QDje75i9SYfwb0qwCuJHAG5xtpW6sUyStyW6gA0/Y=; b=HTJ7O597itAx+W cf/SsgZex301oQqqxJIWOR6Z+AYCImdhdb9BCqdVpoWP+6i+8Fh1OGca3V4F4YSzDlFsLBkA4xh/q FokAUkQOzLexybYiFazTJH8+S9MhRcV4+AXS6AMzDxiqCe0cuhbnspwNjqr4KBX8kD6n96D5l4306 1M7b+t3aEIKglZEAv6enwnetINAKdUePZXLfQs/xfXB4B8xPYv+OTgyleLbOkT47PfZyiTjuEpSKX 4AhKuEIvMachWdN8Z7HR3C4/2jCIQ39PXTE4Zk3cCfP8c7uQ8IC/4EoyITZl0NJt5LJNe4/7QgIkj Ndmd24BtKK4Ry7G1gKZQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hxZ1v-00055i-Mi; Tue, 13 Aug 2019 15:48:11 +0000 Received: from [2001:4bb8:180:1ec3:c70:4a89:bc61:2] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1hxZ1s-0004zn-L0; Tue, 13 Aug 2019 15:48:09 +0000 From: Christoph Hellwig To: Palmer Dabbelt , Paul Walmsley Subject: [PATCH 07/15] riscv: read the hart ID from mhartid on boot Date: Tue, 13 Aug 2019 17:47:39 +0200 Message-Id: <20190813154747.24256-8-hch@lst.de> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190813154747.24256-1-hch@lst.de> References: <20190813154747.24256-1-hch@lst.de> MIME-Version: 1.0 X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Atish Patra , Damien Le Moal , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+infradead-linux-riscv=archiver.kernel.org@lists.infradead.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 Reviewed-by: Atish Patra --- 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 53d7ce74b447..64f8fe84b88f 100644 --- a/arch/riscv/include/asm/csr.h +++ b/arch/riscv/include/asm/csr.h @@ -81,6 +81,7 @@ #define SIE_SEIE (_AC(0x1, UL) << IRQ_S_EXT) /* symbolic CSR names: */ +#define CSR_MHARTID 0xf14 #define CSR_MSTATUS 0x300 #define CSR_MIE 0x304 #define CSR_MTVEC 0x305 diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index bb96bb7b95d2..275c2ab1e990 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -50,6 +50,14 @@ _start_kernel: 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, CSR_MHARTID +#endif + /* Load the global pointer */ .option push .option norelax -- 2.20.1 _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv