From patchwork Fri Oct 9 16:13:25 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 11826635 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A0E2815E6 for ; Fri, 9 Oct 2020 16:17:01 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 035D022261 for ; Fri, 9 Oct 2020 16:17:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="rDHTl2DO" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 035D022261 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-20147-patchwork-kernel-hardening=patchwork.kernel.org@lists.openwall.com Received: (qmail 5976 invoked by uid 550); 9 Oct 2020 16:14:26 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 5897 invoked from network); 9 Oct 2020 16:14:24 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=ljsItlz/aE0P1FDke8OIPGTsfsgvR6SCQ5aAaAr+FuY=; b=rDHTl2DOvEF5lAI8/1xgnH7ewQP7v+fy6WFg1GImMEetNzxgNOGQtQTgFVZA7nJz4m E/V9TlOXQo2zsXvADw6ZjNHpbyo0GyLXq/UcXFopFQ5iYAVttrLb5kwsOMZlNj6d3mq2 v2Z69HCANswfC9sVB06+DLebakWFduI4MBn43M/w9uUpWzAIbBGEejEK5mHvIYhz912n egyvp5xLTL8ReK004BgDAz4wuj45irBJ5zvwJmj0uVsXV1gk7BqZvJNpws7d45/nZF1s sv/UzaMr8Prok4UlE5mODVRqtzkXlZAlSECInu3Rk5zSafDWjBxTBOhp32r/igI3DisM FvIA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=ljsItlz/aE0P1FDke8OIPGTsfsgvR6SCQ5aAaAr+FuY=; b=oTfmzm9GrGag9mhTdrafvDt74yZMbFx0kIFJ3wphJ3xJNPC9GF0xaAMAv8Sj0svFd6 RLEZKoFvRN/howMem0wMLOXf/mLmjpVfLjB+vsck3ZCPA80u6CRfw1Hu8vQcKK2VmFH5 rSYp0izic/E98Djwxc3WVTVHlsrJZncyO4nnCI/m4vz3WAZ93KeRJY09aBF3EWXr34Dm 87G8nKa7nQb+hcMjbKZSOFMPOknYv59ISRBmtxwqAmC2zcxfBHKO2wTXCA7RMpif+9bh wieZ2njhiFyutf6ItD+ha3pC7mjFNU40Zdize9/dRfxK49ctib3iylY8DTdQOmHByYwA 8AFA== X-Gm-Message-State: AOAM533XrHrgUZ8fEOr0+Bnc4xiG9zvW1MsHG3HSpUkykfQfp4ZrXrWP wyD+YoIYZF7XyKoo5d7kM+MnowoQB5uL8PtngnU= X-Google-Smtp-Source: ABdhPJy32BlRlXtKX3ZecjjCx8sYUdqfwZnP6p3172X1KprlyJNmmCaj7qPqSsBQi7a3XNa21VFXuJCMRei9tPIgOic= Sender: "samitolvanen via sendgmr" X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:f693:9fff:fef4:1b6d]) (user=samitolvanen job=sendgmr) by 2002:a25:aaae:: with SMTP id t43mr18851419ybi.404.1602260052989; Fri, 09 Oct 2020 09:14:12 -0700 (PDT) Date: Fri, 9 Oct 2020 09:13:25 -0700 In-Reply-To: <20201009161338.657380-1-samitolvanen@google.com> Message-Id: <20201009161338.657380-17-samitolvanen@google.com> Mime-Version: 1.0 References: <20201009161338.657380-1-samitolvanen@google.com> X-Mailer: git-send-email 2.28.0.1011.ga647a8990f-goog Subject: [PATCH v5 16/29] init: lto: fix PREL32 relocations From: Sami Tolvanen To: Masahiro Yamada , Will Deacon , Steven Rostedt Cc: Peter Zijlstra , Greg Kroah-Hartman , "Paul E. McKenney" , Kees Cook , Nick Desaulniers , clang-built-linux@googlegroups.com, kernel-hardening@lists.openwall.com, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, x86@kernel.org, Sami Tolvanen With LTO, the compiler can rename static functions to avoid global naming collisions. As initcall functions are typically static, renaming can break references to them in inline assembly. This change adds a global stub with a stable name for each initcall to fix the issue when PREL32 relocations are used. Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook --- include/linux/init.h | 31 +++++++++++++++++++++++++++---- 1 file changed, 27 insertions(+), 4 deletions(-) diff --git a/include/linux/init.h b/include/linux/init.h index af638cd6dd52..cea63f7e7705 100644 --- a/include/linux/init.h +++ b/include/linux/init.h @@ -209,26 +209,49 @@ extern bool initcall_debug; */ #define __initcall_section(__sec, __iid) \ #__sec ".init.." #__iid + +/* + * With LTO, the compiler can rename static functions to avoid + * global naming collisions. We use a global stub function for + * initcalls to create a stable symbol name whose address can be + * taken in inline assembly when PREL32 relocations are used. + */ +#define __initcall_stub(fn, __iid, id) \ + __initcall_name(initstub, __iid, id) + +#define __define_initcall_stub(__stub, fn) \ + int __init __stub(void); \ + int __init __stub(void) \ + { \ + return fn(); \ + } \ + __ADDRESSABLE(__stub) #else #define __initcall_section(__sec, __iid) \ #__sec ".init" + +#define __initcall_stub(fn, __iid, id) fn + +#define __define_initcall_stub(__stub, fn) \ + __ADDRESSABLE(fn) #endif #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS -#define ____define_initcall(fn, __name, __sec) \ - __ADDRESSABLE(fn) \ +#define ____define_initcall(fn, __stub, __name, __sec) \ + __define_initcall_stub(__stub, fn) \ asm(".section \"" __sec "\", \"a\" \n" \ __stringify(__name) ": \n" \ - ".long " #fn " - . \n" \ + ".long " __stringify(__stub) " - . \n" \ ".previous \n"); #else -#define ____define_initcall(fn, __name, __sec) \ +#define ____define_initcall(fn, __unused, __name, __sec) \ static initcall_t __name __used \ __attribute__((__section__(__sec))) = fn; #endif #define __unique_initcall(fn, id, __sec, __iid) \ ____define_initcall(fn, \ + __initcall_stub(fn, __iid, id), \ __initcall_name(initcall, __iid, id), \ __initcall_section(__sec, __iid))