From patchwork Thu Apr 8 18:28:37 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 12192159 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=-26.2 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, URIBL_BLOCKED,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham 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 2D6D0C433B4 for ; Thu, 8 Apr 2021 18:30:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0677A61130 for ; Thu, 8 Apr 2021 18:30:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232848AbhDHSaX (ORCPT ); Thu, 8 Apr 2021 14:30:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48706 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232952AbhDHS3x (ORCPT ); Thu, 8 Apr 2021 14:29:53 -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 37EF6C0613B3 for ; Thu, 8 Apr 2021 11:29:09 -0700 (PDT) Received: by mail-qt1-x849.google.com with SMTP id w2so1622632qts.18 for ; Thu, 08 Apr 2021 11:29:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=Rfpjk5lcXiQmXeSx6i4pVVD3rq5mJRtqi0n+qpZr8Ec=; b=uxzGce9H+bQxI3BH5eSnZL/WitMYUsWyiXWRdxtpao5coAXNqK6ECiPrZVE6VXKF2d CFnPSiZQdP6yjcairauODzoA9soSLiJLebgkNNcL2BAyF5MUxAS7P5C4M86UUGzfgPQV LOCPp0ihlS3AG2ENC7WGpgFjZTY5txSczvxDjD7tmVSfQbZ5P9Ym4yOL6BmQy3mZAV+X +6IUfO3iU/PRlH4C6yevg8ke5hfllIcxkEb6BySdOrds6Wpbm3ZPy5IL7Q0UKBS/950R EoKMmBaAN4rDGa+BOE83OyIhGGRij4llD8VaQ6C/cDMFpzuzbYDBUJ8/H9t9SIp+2du0 TTzQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=Rfpjk5lcXiQmXeSx6i4pVVD3rq5mJRtqi0n+qpZr8Ec=; b=SEBcvdWzQrqyTrAMoF9NGEfAQD1CCiYFY6wijVzErLSCxdpVUJ/QiP2KGp8+sWJFJE CrEneKRhebMg34OT67ma2OQYsFHLwOrb2nXq+ibV3X2vWncRr9m4gguY7kEcCnySjTiK 5reDpFREmDCxUgs1oeEiAbrzA8jU3bawvuu3bPGsbi5hDDSf096NMp6eUxqyg/WCsOtO yxQ5WP81VSRUl2r0477GYoEoJ3P+zX4HcdPEf6RUXIOONWa6EFH8pmZ2+eUWqbUF2Oka NVeRPy1y3s+fK5XCrBVWgIYyS7VmAj5XHTwYL9+sHSHv46Eyn4/klFPQa8dT8ytAYmKP 019A== X-Gm-Message-State: AOAM533bqbgr9FD2/z+t4OOn8AaV/RzhA+uuRebMorB/eqRbw2wzCkH6 EFb40fc0lCXD7873u3OYXCyWA6LJ2I9NrdeXYKs= X-Google-Smtp-Source: ABdhPJykkCoAAlAuPh9UWpRW+zA8QhzqRpVC9BlGLOFGa1L0GzjX44pUdqjjGr9/CGnpUy9ZPsJOE4srXjI5kf/aoHk= X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:3560:8505:40a2:e021]) (user=samitolvanen job=sendgmr) by 2002:a0c:e84e:: with SMTP id l14mr10480012qvo.39.1617906548385; Thu, 08 Apr 2021 11:29:08 -0700 (PDT) Date: Thu, 8 Apr 2021 11:28:37 -0700 In-Reply-To: <20210408182843.1754385-1-samitolvanen@google.com> Message-Id: <20210408182843.1754385-13-samitolvanen@google.com> Mime-Version: 1.0 References: <20210408182843.1754385-1-samitolvanen@google.com> X-Mailer: git-send-email 2.31.1.295.g9ea45b61b8-goog Subject: [PATCH v6 12/18] arm64: implement function_nocfi From: Sami Tolvanen To: Kees Cook Cc: Nathan Chancellor , Nick Desaulniers , Masahiro Yamada , Will Deacon , Jessica Yu , Arnd Bergmann , Tejun Heo , "Paul E. McKenney" , Christoph Hellwig , Peter Zijlstra , Sedat Dilek , Mark Rutland , Catalin Marinas , bpf@vger.kernel.org, linux-hardening@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, Sami Tolvanen Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org With CONFIG_CFI_CLANG, the compiler replaces function addresses in instrumented C code with jump table addresses. This change implements the function_nocfi() macro, which returns the actual function address instead. Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook Acked-by: Mark Rutland Tested-by: Nathan Chancellor --- arch/arm64/include/asm/memory.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index 0aabc3be9a75..3a6f9df63606 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -321,6 +321,22 @@ static inline void *phys_to_virt(phys_addr_t x) #define virt_to_pfn(x) __phys_to_pfn(__virt_to_phys((unsigned long)(x))) #define sym_to_pfn(x) __phys_to_pfn(__pa_symbol(x)) +#ifdef CONFIG_CFI_CLANG +/* + * With CONFIG_CFI_CLANG, the compiler replaces function address + * references with the address of the function's CFI jump table + * entry. The function_nocfi macro always returns the address of the + * actual function instead. + */ +#define function_nocfi(x) ({ \ + void *addr; \ + asm("adrp %0, " __stringify(x) "\n\t" \ + "add %0, %0, :lo12:" __stringify(x) \ + : "=r" (addr)); \ + addr; \ +}) +#endif + /* * virt_to_page(x) convert a _valid_ virtual address to struct page * * virt_addr_valid(x) indicates whether a virtual address is valid