From patchwork Tue Sep 29 21:46:20 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 11807179 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 14F98618 for ; Tue, 29 Sep 2020 21:49:39 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 51B9720774 for ; Tue, 29 Sep 2020 21:49:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="b55hwPid" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 51B9720774 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-20048-patchwork-kernel-hardening=patchwork.kernel.org@lists.openwall.com Received: (qmail 32473 invoked by uid 550); 29 Sep 2020 21:47:27 -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 32301 invoked from network); 29 Sep 2020 21:47:25 -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=/vP7q5BBB0uTfRm2AgwdilGSRfsWzFPQ2WkTiyoFr6c=; b=b55hwPidpBtwXSYzPL7nG9/Vda7JuMVr/EGJixbfG0vXQwUBtPjkDoj3MJOTqZMsWM vzguUIrKQvSlcJMS9LcTLx25efyz9HzS/XNyEl+Vmt3JZFYWS9Xi9CW480UD18Iv8V/8 Zv0q3PdFWw+MxCu1kPSRKo5b5kauZeRMwrGkfiXKdlBUKbyUb+Mx09RiNdFeO5g1b1k/ MGs4GivcBr1kLWAINFKbVMCXqvyatQdyLKZ3K2d+FSPXYNUWpizBFCZ7ExOm+k6gsGZr 9pRIvsrPB/pkdVgUtISLhxoJY5If1dpdNi3Vrr64TIoPSMdOxtuHEgcrwzGEARSD2d7Y rM6w== 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=/vP7q5BBB0uTfRm2AgwdilGSRfsWzFPQ2WkTiyoFr6c=; b=VQZlMTBDgzbrQNnSEoHRTfieSC8GReOTOTdspMBgH/EZT0Jla4QbCIsfv5KUI0+jaP AQADRDmfpxXoBzTLVD55aq5f0CA7BHHBNV+eX+Az9pbQdFjHFiwB7G4jKyxJunUBG/Kv XHyRC0EA+ojBX7TJUU6B0/s+gNsYPe9nrGX49OQyFdaFGzTlMeXB4imvxsCdfkfD0Pod nxZDj4zl0wsObM//mJtvVIvz1exV29Bwtzm24yVKhL+YOU7K38Pv7oh2HHTopthyzne0 u3+yVGatbDCRcwX4mRw75LOUs3wdt5zVF0EO8yPfufH/0h2Xz3/Yct2WRQ7opz+QKUdI YTxg== X-Gm-Message-State: AOAM531rq7uxK+SNTt5BKUz07tup8jTU3xXI85tG7a4NDg487qxQWx9t DxP5RqivrJG5Wj3heVXCfZH2SCkF5gvat7i3KJI= X-Google-Smtp-Source: ABdhPJzwunn8/64a+JvNFjvDzCLI2jH4jHUm6kjJgtH3L7MwJCKNh04+JiRlVd1IwEJ79vkmzQAo7H0Oi+ZByvS+NaY= 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:a63:e813:: with SMTP id s19mr4805529pgh.33.1601416033950; Tue, 29 Sep 2020 14:47:13 -0700 (PDT) Date: Tue, 29 Sep 2020 14:46:20 -0700 In-Reply-To: <20200929214631.3516445-1-samitolvanen@google.com> Message-Id: <20200929214631.3516445-19-samitolvanen@google.com> Mime-Version: 1.0 References: <20200929214631.3516445-1-samitolvanen@google.com> X-Mailer: git-send-email 2.28.0.709.gb0816b6eb0-goog Subject: [PATCH v4 18/29] 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))