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 161EDC43218 for ; Mon, 10 Jun 2019 22:16:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E266B2082E for ; Mon, 10 Jun 2019 22:16:45 +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="g7MV9hKQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390330AbfFJWQp (ORCPT ); Mon, 10 Jun 2019 18:16:45 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:53826 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390276AbfFJWQl (ORCPT ); Mon, 10 Jun 2019 18:16:41 -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=lVE4VBqJB+KkG+FIxfoQqL75aQVlp7EZak10nik7k0k=; b=g7MV9hKQoNw5gI26t9jxExxpCz y+RoLH7nrhvOd0+tEwTwrMivkxztKInbGwugrmpiQFPeopqZoRhBHypBsX+F4rKxzss1ujMWclj2L V2ZngcPWW3tXn6sAIx1eV9VUPJfqbjvq8WK5ebICyPboFn5qZ3m95ENz1v70yAAt0F7E7bVo+1Yjv skAqfYXdAeo1RmOxNKqt2FyihTKFOXZubw9xhxq4COqdDGAHX/b2C0oRMvH5jv+ou/cPV7+SlC1LO lWDSUEv7+HmoZ2qD0Ji4RSL9S7vB/ZQg8bfcFXHneu7AvuwKzA4kPDZl+wsCwWQo8U0e+HsYnUBhM 3wbqTVdQ==; Received: from 089144193064.atnat0002.highway.a1.net ([89.144.193.64] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1haSal-000319-AM; Mon, 10 Jun 2019 22:16:39 +0000 From: Christoph Hellwig To: Palmer Dabbelt Cc: Damien Le Moal , linux-riscv@lists.infradead.org, uclinux-dev@uclinux.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH 06/17] riscv: clear the instruction cache and all registers when booting Date: Tue, 11 Jun 2019 00:16:10 +0200 Message-Id: <20190610221621.10938-7-hch@lst.de> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190610221621.10938-1-hch@lst.de> References: <20190610221621.10938-1-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 When we get booted we want a clear slate without any leaks from previous supervisors or the firmware. Flush the instruction cache and then clear all registers to known good values. This is really important for the upcoming nommu support that runs on M-mode, but can't really harm when running in S-mode either. Vaguely based on the concepts from opensbi. Signed-off-by: Christoph Hellwig --- arch/riscv/kernel/head.S | 83 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 83 insertions(+) diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index 4e46f31072da..5681179183d4 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -11,6 +11,7 @@ #include #include #include +#include __INIT ENTRY(_start) @@ -18,6 +19,12 @@ ENTRY(_start) csrw CSR_SIE, zero csrw CSR_SIP, zero + /* flush the instruction cache */ + fence.i + + /* Reset all registers except ra, a0,a1 */ + call reset_regs + /* Load the global pointer */ .option push .option norelax @@ -160,6 +167,82 @@ relocate: j .Lsecondary_park END(_start) +ENTRY(reset_regs) + li sp, 0 + li gp, 0 + li tp, 0 + li t0, 0 + li t1, 0 + li t2, 0 + li s0, 0 + li s1, 0 + li a2, 0 + li a3, 0 + li a4, 0 + li a5, 0 + li a6, 0 + li a7, 0 + li s2, 0 + li s3, 0 + li s4, 0 + li s5, 0 + li s6, 0 + li s7, 0 + li s8, 0 + li s9, 0 + li s10, 0 + li s11, 0 + li t3, 0 + li t4, 0 + li t5, 0 + li t6, 0 + csrw sscratch, 0 + +#ifdef CONFIG_FPU + csrr t0, misa + andi t0, t0, (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D) + bnez t0, .Lreset_regs_done + + li t1, SR_FS + csrs sstatus, t1 + fmv.s.x f0, zero + fmv.s.x f1, zero + fmv.s.x f2, zero + fmv.s.x f3, zero + fmv.s.x f4, zero + fmv.s.x f5, zero + fmv.s.x f6, zero + fmv.s.x f7, zero + fmv.s.x f8, zero + fmv.s.x f9, zero + fmv.s.x f10, zero + fmv.s.x f11, zero + fmv.s.x f12, zero + fmv.s.x f13, zero + fmv.s.x f14, zero + fmv.s.x f15, zero + fmv.s.x f16, zero + fmv.s.x f17, zero + fmv.s.x f18, zero + fmv.s.x f19, zero + fmv.s.x f20, zero + fmv.s.x f21, zero + fmv.s.x f22, zero + fmv.s.x f23, zero + fmv.s.x f24, zero + fmv.s.x f25, zero + fmv.s.x f26, zero + fmv.s.x f27, zero + fmv.s.x f28, zero + fmv.s.x f29, zero + fmv.s.x f30, zero + fmv.s.x f31, zero + csrw fcsr, 0 +#endif /* CONFIG_FPU */ +.Lreset_regs_done: + ret +END(reset_regs) + __PAGE_ALIGNED_BSS /* Empty zero page */ .balign PAGE_SIZE -- 2.20.1