From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ej1-x62c.google.com (mail-ej1-x62c.google.com [IPv6:2a00:1450:4864:20::62c]) by sourceware.org (Postfix) with ESMTPS id D30333858D1E for ; Tue, 29 Nov 2022 19:28:38 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org D30333858D1E Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-ej1-x62c.google.com with SMTP id ml11so11367265ejb.6 for ; Tue, 29 Nov 2022 11:28:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=LvqYE5R5HeLMtZ7fk1xXT4J51FyYRYkpq9XDrr3X4TU=; b=AGv/5+IbhOn4jVZuS4HQNzi4os1HUroaclHtFmaijuCz4jR4l6x+4WcokGi2B+lF21 yiOMuKj1oPld6ujtD84K6eceLKq0yi7568HMDq6CTfYwYOMz+qFvdAewihbp9lOjXYIj tN2aolffRjaWnCzqsqSWF90/c7DnJHutwvtFh2XrBafswxqhBeNUnPS4Av3ZhGfMzPh4 5FB8daGCe6Px07XNG/QVvXvmrs2bQ1NLC3DSv1wyVapWqug8I3W27hIMrS9GYL4h+OFX snkflq1n2J/Hr6tkPoZjvnSQJHQkCFty4PjndHmSuBcAFH4pNuH9Z0Re9veUPVeibUvr 75/A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=LvqYE5R5HeLMtZ7fk1xXT4J51FyYRYkpq9XDrr3X4TU=; b=gwQqFhmQA9jqZk3+VhdDsqGTip33ZrNYv6PuZUa0m4HRRYwtHLfMYI0EWYN6YvrvIW Oxg5FH5h78kzn5YX241lCUcAaACYVhLXoCJfpdGrwCaMIc494EvAIFyYst8f5MNxQXsQ XELutmjFJdbLMTXhgmcbBVFmxZgwhMhm1+weh04Yf4sLSMPX9snQAYZSceo5/riATiMu ve5t3Mu93SP34UYezBOiN1+9gadHKvJg/DNVs6A/Qq/IOrNIOLZmBbbu8NrAH/hCeH2o RyzysGtvmTvL4epSsPbJnkTcfT9J2XMfSEdWzZTX2TJx5jl+wcUsJ2rMB8MPw+mSF/hx TfXA== X-Gm-Message-State: ANoB5pl4Y0fgEpSYMb/+UzTvpmAbnMTNdiMoHmBLsXKi2gOzKS0zZ3oF dSav1/prwIbLzxPBBsMLsdNGZCdjExB8gr2gjmcSeULLGPDGcA== X-Google-Smtp-Source: AA0mqf5MyTqnfFoFchlvzF5Cc5GXE2Kb3Wo8NAetXQeMR1N+ON2ai6Bmx56VApUXHIuacURwG1WLMalUeGh0nwxSB+o= X-Received: by 2002:a17:907:9895:b0:7c0:7db3:82e3 with SMTP id ja21-20020a170907989500b007c07db382e3mr7394653ejc.480.1669750117663; Tue, 29 Nov 2022 11:28:37 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: From: "Lad, Prabhakar" Date: Tue, 29 Nov 2022 19:28:11 +0000 Message-ID: Subject: Re: [QUERY]: Adding support for a platform To: Palmer Dabbelt Cc: binutils@sourceware.org, linux-riscv Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-0.7 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: Hi Palmer, Oops I should have included linux-riscv to the CC list here (doing it now) On Tue, Nov 29, 2022 at 7:20 PM Palmer Dabbelt wrote: > > On Tue, 29 Nov 2022 11:16:29 PST (-0800), binutils@sourceware.org wrote: > > Hi All, > > > > If this is not the right place to ask this question please let me know. > > > > So we have a RISCV platform (Renesas RZ/Five) for which we need to > > adjust the TEXT_START_ADDR. So below are my queries: > > * What is the procedure for upstreaming? > > * Are patches accepted for individual platforms (for adjusting TEXT_STA= RT_ADDR)? > > Is this still related to that bug with the static binaries you'd > mentioned before? I think we'd really need to figure out the root cause > before we can make a reasoned decision here, my guess would be that > changing TEXT_START_ADDR just works around the real bug. > Below is the root cause and the solution: TEXT_START_ADDR is the start of the text segment of an application. This is being set to 0x10000 for RISCV platforms. So when an application is compiled with the static flag the load would start from 0x10000 - xyz (depending on size of the application) Entry point 0x101c0 There are 5 program headers, starting at offset 64Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flags Align LOAD 0x0000000000000000 0x0000000000010000 0x0000000000010000 0x0000000000059b48 0x0000000000059b48 R E 0x1000 LOAD 0x0000000000059b60 0x000000000006ab60 0x000000000006ab60 0x0000000000001f68 0x0000000000003528 RW 0x1000 So for the above application which is compiled statically we can see the entry point is 0x101c0 and load 0x0000000000010000. Andes AX45MP cores have local memory ILM and DLM that are mapped in the region H=E2=80=990_0003_0000 - H=E2=80=990_0004_FFFF on the RZ/Five SoC= . When the virtual address falls in this range the MMU doesn't trigger a page fault and assumes the virtual address as physical address and hence the application fails to run (panics somewhere). So to avoid this issue we set the TEXT_START_ADDR to 0x50000 so that the virtual address of any statically compiled application does not fall in the range of H=E2=80=990_0003_0000 - H=E2=80=990_0004_FFFF. Elf file type is EXEC (Executable file) Entry point 0x504e4 There are 5 program headers, starting at offset 64 Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flags Align LOAD 0x0000000000000000 0x0000000000050000 0x0000000000050000 0x0000000000057dc8 0x0000000000057dc8 R E 0x1000 LOAD 0x00000000000585b8 0x00000000000a95b8 0x00000000000a95b8 0x0000000000004ee0 0x00000000000064b0 RW 0x1000 NOTE 0x0000000000000158 0x0000000000050158 0x0000000000050158 0x0000000000000044 0x0000000000000044 R 0x4 So now with the fix for statically compiled applications we can see its offsetted and entry point is 0x504e4 and load is at 0x0000000000050000. So with this we are for sure the MMU will always trigger a page fault. Cheers, Prabhakar