From patchwork Thu Mar 18 17:10:57 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 12148803 X-Patchwork-Delegate: bpf@iogearbox.net 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=-26.3 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,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 8C954C41519 for ; Thu, 18 Mar 2021 17:12:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6129864F4D for ; Thu, 18 Mar 2021 17:12:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232291AbhCRRLn (ORCPT ); Thu, 18 Mar 2021 13:11:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33166 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232283AbhCRRLX (ORCPT ); Thu, 18 Mar 2021 13:11:23 -0400 Received: from mail-pl1-x649.google.com (mail-pl1-x649.google.com [IPv6:2607:f8b0:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D681EC06174A for ; Thu, 18 Mar 2021 10:11:22 -0700 (PDT) Received: by mail-pl1-x649.google.com with SMTP id x7so22599211plg.18 for ; Thu, 18 Mar 2021 10:11:22 -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=PeAEi4QdQeJS0R2WYWNNntX7QF/OnwnEUYEO8FB/zZI=; b=p+VrkP1bqZI10VP8EeeZrzzfoI1GjtWoEBRuBE726XK/gDRTExpkpo8vfdSH/r6qQ2 fOHKt1juhQxrQX6cPPMTifNTZixG8rFVdvoGNuSuYPxjZVs2EkOF1lcit3KaS49mPZ8z IQOBi7STpHBUIWzQ5ZbW05JFEpfzqGDRrLWE4nIbfgbgwW0f2a/6+/NvWVZQIPm96o7N I++3MhM7OLsD8NpuK5qhBdlWedJp3H/fYNTk/el3qX4LG+Jk4NRA79tjSVy1YmmYUQk0 1tj5qVOJAW3NP909IVQvUiiUoKjnZ8ZK9jEGED8pRZSAEUtB/GBEOGKsqXsDo/bIKAnn RFjw== 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=PeAEi4QdQeJS0R2WYWNNntX7QF/OnwnEUYEO8FB/zZI=; b=k6SmEMxk8x0er4F6JlZTYGJbR83XPYoSZy32j3fSrqEJWH9cgna7gl/mloxXEP1Od6 wD20komP4wXxMpSc6fkStLTxfnjODb8qwu9tTEFlGmln9MkOA6+ggKeztUnjv6N1jiQo ljdL4UpOzMAO8fia1HUrd1KgwSh1RWl0MufgIum+bIysizelo/WHBpiNDv4M2ctCwF+0 0CmoV4nmgvpaKp/KeZEUeDdaRBbVMtbGpARP17qqx5+MuOkNJWY2fUnJlPeS8JfXBNcr x7Tf59ajVr66QXj7bj/pQZslh5iBmF3gVXhM5xsjjoOood09Uh5ZFXU0Xz7iQLWtVgcI Bv8g== X-Gm-Message-State: AOAM532vPDpMt+3Y1PCWVP71/ENBKzEHs5bVHJ3p2fxCvwgPHeSKk6UN H1ef5nrbGZcWGndMcyAki09kDzp73wkuVJehxSE= X-Google-Smtp-Source: ABdhPJx8cHucnyP+Aa+4tX9UaXIRGtXiznnlELJLcS5vzBI/KUq73zcAaMJL61KmuRuPI9myO+PJeQ6WezcQTaT+iSM= X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:c0d7:a7ba:fb41:a35a]) (user=samitolvanen job=sendgmr) by 2002:a17:902:7401:b029:e4:5992:e64a with SMTP id g1-20020a1709027401b02900e45992e64amr10565108pll.75.1616087482135; Thu, 18 Mar 2021 10:11:22 -0700 (PDT) Date: Thu, 18 Mar 2021 10:10:57 -0700 In-Reply-To: <20210318171111.706303-1-samitolvanen@google.com> Message-Id: <20210318171111.706303-4-samitolvanen@google.com> Mime-Version: 1.0 References: <20210318171111.706303-1-samitolvanen@google.com> X-Mailer: git-send-email 2.31.0.291.g576ba9dcdaf-goog Subject: [PATCH v2 03/17] mm: add generic __va_function and __pa_function macros 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 , 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, 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 means that __pa_symbol(function) returns the physical address of the jump table entry instead of the actual function, which may not work as the jump table code will immediately jump to a virtual address that may not be mapped. To avoid this address space confusion, this change adds generic definitions for __va_function and __pa_function, which architectures that support CFI can override. The typical implementation of the __va_function macro would use inline assembly to take the function address, which avoids compiler instrumentation. Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook --- include/linux/mm.h | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index 64a71bf20536..a0d285cd59ce 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -116,6 +116,14 @@ extern int mmap_rnd_compat_bits __read_mostly; #define __pa_symbol(x) __pa(RELOC_HIDE((unsigned long)(x), 0)) #endif +#ifndef __va_function +#define __va_function(x) (x) +#endif + +#ifndef __pa_function +#define __pa_function(x) __pa_symbol(__va_function(x)) +#endif + #ifndef page_to_virt #define page_to_virt(x) __va(PFN_PHYS(page_to_pfn(x))) #endif