From patchwork Sun Mar 22 11:00:28 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Alexandre Ghiti X-Patchwork-Id: 11451629 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9E0BA92A for ; Sun, 22 Mar 2020 11:08:07 +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 7AEE920753 for ; Sun, 22 Mar 2020 11:08:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="e/sn9njf" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7AEE920753 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ghiti.fr Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-riscv-bounces+patchwork-linux-riscv=patchwork.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:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: Content-Transfer-Encoding:Content-Type: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=cMNEg3KGsTOtln22J6DC1lXE5+E5SXEYXJKCK9yDu9U=; b=e/sn9njfUKvZfh 29gn12z1kEbvGhSPnx4tfIVpnEDFmYz1nPzdelDJ8wqrmUMc4ZnklS/QhnNwk1Y8/48lPZ3o/c+KY 3D7+Vk1DabbjWc3BCNtxAc0SATVUhREa3KILMo/iNWrJVoYUBqEtptxT5VfNTspa5h49GMauVgeJM yIwMToUwpwy7RMDALxQ4qaB06r633vbhMZSfgisWiQeLMtel+f0L2IaYoWbp3hwxeZjptqZMJ41eN VUe10fvngk+djD+cUAgLhpCPi5ys+z9kY6uBeeP01YL7V/s6DR1W2Gbbb87VT4Fg7vEOJLjjTSAwE R1Xliae860lCflPi3iTg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jFySa-00011Q-M3; Sun, 22 Mar 2020 11:08:04 +0000 Received: from relay11.mail.gandi.net ([217.70.178.231]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jFySY-00010N-1k for linux-riscv@lists.infradead.org; Sun, 22 Mar 2020 11:08:03 +0000 Received: from localhost.localdomain (lfbn-lyo-1-453-25.w2-7.abo.wanadoo.fr [2.7.45.25]) (Authenticated sender: alex@ghiti.fr) by relay11.mail.gandi.net (Postfix) with ESMTPSA id 05D5610000F; Sun, 22 Mar 2020 11:07:56 +0000 (UTC) From: Alexandre Ghiti To: Paul Walmsley , Palmer Dabbelt , Zong Li , Anup Patel , Christoph Hellwig , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [RFC PATCH 7/7] riscv: Explicit comment about user virtual address space size Date: Sun, 22 Mar 2020 07:00:28 -0400 Message-Id: <20200322110028.18279-8-alex@ghiti.fr> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200322110028.18279-1-alex@ghiti.fr> References: <20200322110028.18279-1-alex@ghiti.fr> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200322_040802_226530_354C6BF8 X-CRM114-Status: UNSURE ( 8.30 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -0.7 (/) X-Spam-Report: SpamAssassin version 3.4.3 on bombadil.infradead.org summary: Content analysis details: (-0.7 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at https://www.dnswl.org/, low trust [217.70.178.231 listed in list.dnswl.org] 0.0 SPF_NONE SPF: sender does not publish an SPF Record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record 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: Alexandre Ghiti Sender: "linux-riscv" Errors-To: linux-riscv-bounces+patchwork-linux-riscv=patchwork.kernel.org@lists.infradead.org Define precisely the size of the user accessible virtual space size for sv32/39/48 mmu types and explain why the whole virtual address space is split into 2 equal chunks between kernel and user space. Signed-off-by: Alexandre Ghiti Reviewed-by: Anup Patel Reviewed-by: Palmer Dabbelt --- arch/riscv/include/asm/pgtable.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h index 06361db3f486..be117a0b4ea1 100644 --- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -456,8 +456,15 @@ static inline int ptep_clear_flush_young(struct vm_area_struct *vma, #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) /* - * Task size is 0x4000000000 for RV64 or 0x9fc00000 for RV32. - * Note that PGDIR_SIZE must evenly divide TASK_SIZE. + * Task size is: + * - 0x9fc00000 (~2.5GB) for RV32. + * - 0x4000000000 ( 256GB) for RV64 using SV39 mmu + * - 0x800000000000 ( 128TB) for RV64 using SV48 mmu + * + * Note that PGDIR_SIZE must evenly divide TASK_SIZE since "RISC-V + * Instruction Set Manual Volume II: Privileged Architecture" states that + * "load and store effective addresses, which are 64bits, must have bits + * 63–48 all equal to bit 47, or else a page-fault exception will occur." */ #ifdef CONFIG_64BIT #define TASK_SIZE (PGDIR_SIZE * PTRS_PER_PGD / 2)