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=-14.6 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=no 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 3F33BC433DF for ; Fri, 31 Jul 2020 18:37:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 18A8E22B3F for ; Fri, 31 Jul 2020 18:37:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="UHl+j2V9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387809AbgGaShu (ORCPT ); Fri, 31 Jul 2020 14:37:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60640 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730040AbgGaSht (ORCPT ); Fri, 31 Jul 2020 14:37:49 -0400 Received: from mail-qt1-x849.google.com (mail-qt1-x849.google.com [IPv6:2607:f8b0:4864:20::849]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4D922C061574 for ; Fri, 31 Jul 2020 11:37:49 -0700 (PDT) Received: by mail-qt1-x849.google.com with SMTP id r9so21616832qtp.7 for ; Fri, 31 Jul 2020 11:37:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=xWSYjHc+nNdSzqwJCR0Bklwg1NIcyWlbe0Z3kPyxnWY=; b=UHl+j2V9dhsDIpXllhTd7jR0aoK7gz3zEDu2e8D2wo87p2jNh2PEv05B77btBa2WHg t4q9x8YrBGZ9mWVt2w/JAycC+YM363ctKxR6EZAiLJ1H2iARbDjGX7llw1Nc+VeYE9es yLcU/z3RRBx0nUqSGNv5//jg5qgnMt5Wu8m3R/7GIOqQxw0kKjBTswm1QjKpSO78MsPD 3QPrOmOcbwtKQa5BO4IsGOI0g/U7+2GEkC1glS9jR40LCLfy1gPodeZY8yYY8H+aPQMA RSRRVYFCS/Ib7J0kJ1dmF/hxt8HVvPuyhMZglgFrgZH3/I5FkvLkG/kOCu9yAgBrbpJl xHlQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=xWSYjHc+nNdSzqwJCR0Bklwg1NIcyWlbe0Z3kPyxnWY=; b=Tv6wYv0GMpJEi8TP3y5qLTX0saI4gwqkH/Xud4L2YbTOaOn+H1XlLddGaTliKcwgcK nYGrs6HbjsmRG0YGhpFiYIFDiqvXG5yiAs2pwty+HAxGm5NqjLI/z0dIkgiFIscQ/0aI EGyPhhrkzUzTuTjH9q+2eXTyLnVYAlZCVaxtkclh9uBLa0ouvO5i8EOk5WJZ7SdBVDVm /74ljA68wgSfcO7mz+3vnzlt/X8GoVadiQvUY0GUeKnbs6qkTcydGiBjATVvnh3+x/fL +0Y4aEMtlVM1sgJWwPP9wb/WQHHO9b5otEJkoHak9tKv0oN6eUjb4xfY7lWc/0CB9BZa 6FfA== X-Gm-Message-State: AOAM531PMvMsXG3Irgkt2reuNOceIZlQDu7YuugzHgLIVcceNPuqbaHz cA8TMxUNGDOo414oU3Z5FBneglPBaJBHOEY= X-Google-Smtp-Source: ABdhPJwXJL3gk9kvQMJJpLmkcSGCU6nZqceKkw9xlltDxuzwPaAHb7crDooksHey6e2zSNoOpkyE2MgqTt+x1Wk= X-Received: by 2002:a0c:d44e:: with SMTP id r14mr5459448qvh.105.1596220668284; Fri, 31 Jul 2020 11:37:48 -0700 (PDT) Date: Fri, 31 Jul 2020 14:37:42 -0400 Message-Id: <20200731183745.1669355-1-ckennelly@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.28.0.163.g6104cc2f0b6-goog Subject: [PATCH 0/2 v2] Selecting Load Addresses According to p_align From: Chris Kennelly To: Alexander Viro , Alexey Dobriyan , Song Liu Cc: David Rientjes , Ian Rogers , Hugh Dickens , Andrew Morton , Suren Baghdasaryan , Sandeep Patil , Fangrui Song , Nick Desaulniers , clang-built-linux@googlegroups.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Chris Kennelly Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The current ELF loading mechancism provides page-aligned mappings. This can lead to the program being loaded in a way unsuitable for file-backed, transparent huge pages when handling PIE executables. While specifying -z,max-page-size=0x200000 to the linker will generate suitably aligned segments for huge pages on x86_64, the executable needs to be loaded at a suitably aligned address as well. This alignment requires the binary's cooperation, as distinct segments need to be appropriately paddded to be eligible for THP. For binaries built with increased alignment, this limits the number of bits usable for ASLR, but provides some randomization over using fixed load addresses/non-PIE binaries. Changes V1 -> V2: * Added test Chris Kennelly (2): fs/binfmt_elf: Use PT_LOAD p_align values for suitable start address. Add self-test for verifying load alignment. fs/binfmt_elf.c | 24 ++++++++ tools/testing/selftests/exec/.gitignore | 1 + tools/testing/selftests/exec/Makefile | 9 ++- tools/testing/selftests/exec/load_address.c | 68 +++++++++++++++++++++ 4 files changed, 100 insertions(+), 2 deletions(-) create mode 100644 tools/testing/selftests/exec/load_address.c -- 2.28.0.163.g6104cc2f0b6-goog