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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5FE86C001E0 for ; Wed, 2 Aug 2023 18:37:04 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qRGhz-0001AY-Jv; Wed, 02 Aug 2023 14:36:31 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qRGhx-0001A8-Uv for qemu-devel@nongnu.org; Wed, 02 Aug 2023 14:36:30 -0400 Received: from mail-pl1-x629.google.com ([2607:f8b0:4864:20::629]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qRGhw-00068D-Cu for qemu-devel@nongnu.org; Wed, 02 Aug 2023 14:36:29 -0400 Received: by mail-pl1-x629.google.com with SMTP id d9443c01a7336-1bc1c1c68e2so1278865ad.3 for ; Wed, 02 Aug 2023 11:36:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1691001387; x=1691606187; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=suHTtANtdNZ60LtqRiqaCJt0FRomDSx/Tb20soN1Ldk=; b=zneSIdYthpzfVYsHnWoLy3G6KJ9bo9ED/Ld1pZn+MeVeK0jKcWTrWc0A6A/CQfVrfX o4m4sHWtE+ZTJBYdSCXYYdlboTS6T92WXk/La2L6sb8nAOJ5elltgPXf7MTFY8z8qKbx wlDjTGrAPQANpIRf/qfhJLePn8eMLYwb71yBt47avATb7nZyjyukJXBNGwwpHde9il8d 9VHDUHSbJ74IzaZJy6wEF7seNYojIfpV7ehWvU2+VRykTTrdgzsK9XUn3Qdsz0VPcE79 DxQrlQFkvunREEmHpBKDqm5tZPROF6u4kNGydj/9VHGq35dRtyKZN40vjGQWLPUWTECr Brpg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1691001387; x=1691606187; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=suHTtANtdNZ60LtqRiqaCJt0FRomDSx/Tb20soN1Ldk=; b=Cj2frRfakkjtvWgkMZZggCn88Fya73m1OMKFQCVGrcSGssmMVd3cuNB5qk26Q8WTFb MZXjNC4BmbpgSa9kf29Z6qjclqV0jH3WIjYf4BRG2fnZwLx/nlHnbRy6h0i3Y95DOKu/ JPX8gyE45oisZHenhP5nfh8tuYjlw7x2Y9ttXE5TYlI9eAlNc1uO+PbmD+xFOqihUJF4 l9Zmf4msVy7VIAcpQTnlD4yYK0KG9SfULqTkZc+gUpurdYc8OVHqBnMf2LUktcORf4eM AQuJ35RxR4W/8R/ew1YyPzWYQd/ShthkdrFHttp54NCjA1bHt7TJcMpJMqOQxBxgahtT uFmw== X-Gm-Message-State: ABy/qLayhhvjIx30qlBmj/JAoImygvINQBJX7iOBEEhv/ITuUTe6cCdG TjAtU1RR+RSnqx/Sx51aQga+eg== X-Google-Smtp-Source: APBJJlGIfOiVyFd/TefuC1EsKn2WaRyrodQOvsyQ+EN/952vRValbRSTMEyB8l92d3rPoBS5pbIM1g== X-Received: by 2002:a17:902:d2c9:b0:1bb:3406:a612 with SMTP id n9-20020a170902d2c900b001bb3406a612mr16053935plc.57.1691001386777; Wed, 02 Aug 2023 11:36:26 -0700 (PDT) Received: from ?IPV6:2602:47:d490:6901:b659:bbad:1a22:7ef9? ([2602:47:d490:6901:b659:bbad:1a22:7ef9]) by smtp.gmail.com with ESMTPSA id jk17-20020a170903331100b001b9e59d6ddesm12764197plb.124.2023.08.02.11.36.25 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 02 Aug 2023 11:36:26 -0700 (PDT) Message-ID: <5b57cd92-149e-5f72-d946-082ebf0bfc9c@linaro.org> Date: Wed, 2 Aug 2023 11:36:24 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH v6 8/8] linux-user: Load pie executables at upper memory Content-Language: en-US To: Helge Deller , qemu-devel@nongnu.org Cc: Laurent Vivier , Paolo Bonzini , Joel Stanley , Akihiko Odaki References: <20230801232745.4125-1-deller@gmx.de> <20230801232745.4125-9-deller@gmx.de> From: Richard Henderson In-Reply-To: <20230801232745.4125-9-deller@gmx.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=2607:f8b0:4864:20::629; envelope-from=richard.henderson@linaro.org; helo=mail-pl1-x629.google.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.102, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 8/1/23 16:27, Helge Deller wrote: > +/* where to map binaries? */ > +#if HOST_LONG_BITS == 64 && TARGET_ABI_BITS == 64 > +# define TASK_UNMAPPED_BASE_PIE 0x5500000000 > +# define TASK_UNMAPPED_BASE 0x7000000000 > +#elif HOST_LONG_BITS == 64 && TARGET_ABI_BITS == 32 > +# define TASK_UNMAPPED_BASE_PIE 0x00300000 > +# define TASK_UNMAPPED_BASE (GUEST_ADDR_MAX - 0x20000000 + 1) > +#else /* HOST_LONG_BITS == 32 && TARGET_ABI_BITS == 32 */ > +# define TASK_UNMAPPED_BASE_PIE 0x00000000 > +# define TASK_UNMAPPED_BASE 0x40000000 > +#endif It would probably be easier to follow if you use the kernel's name: ELF_ET_DYN_BASE. Should be in linux-user/$GUEST/target_mmap.h with TASK_UNMAPPED_BASE, per my comment vs patch 7. > + /* do sanity checks on guest memory layout */ > + if (mmap_next_start >= GUEST_ADDR_MAX) { > + mmap_next_start = GUEST_ADDR_MAX - 0x1000000000 + 1; > + } What in the world is that random number? It certainly won't compile on 32-bit host, and certainly isn't relevant to a 32-bit guest. > + if (TASK_UNMAPPED_BASE_PIE >= mmap_next_start) { > + fprintf(stderr, "Memory too small for PIE executables.\n"); > + exit(EXIT_FAILURE); > + } Really bad timing for this diagnostic. What if a PIE executable isn't even being used? Both TASK_UNMAPPED_BASE and ELF_ET_DYN_BASE could be computed in main (or a subroutine), when reserved_va is assigned. r~