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=-14.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 8A077C282CE for ; Thu, 23 May 2019 00:57:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 390502089E for ; Thu, 23 May 2019 00:57:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=android.com header.i=@android.com header.b="lrXxW/5u" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729677AbfEWA5T (ORCPT ); Wed, 22 May 2019 20:57:19 -0400 Received: from mail-pg1-f195.google.com ([209.85.215.195]:37949 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727305AbfEWA5T (ORCPT ); Wed, 22 May 2019 20:57:19 -0400 Received: by mail-pg1-f195.google.com with SMTP id v11so2177917pgl.5 for ; Wed, 22 May 2019 17:57:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=android.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=OCcxFZ8u217pCLU2+Z7QXQBb4BZSJxt773aXmFVctu0=; b=lrXxW/5uiapy3w5HtMfhyB3Bk6NFY9FVuWaL71RTtfJPQMsRDPNUJ7ipQQta880l5N 8GpHNpjXdvqbRNY+BQ07w0p05xblGT3W5Ka+LFkYA2Huk3F0A6Ztn4p1oSeVkpdpoxLE LdAXKWYp/K9oGn3cDvAwA1Fr6ekNdwdeBAKUtMMSxb+WkpnKgkxcqTZODoWSQJfA9tUs cpYaq0PTzWmljBUSbDbC3aXbPRLGwxCP3t3uxoTq5tZxmd7gMpoPfBTAovC8hsRFxImI 3WUaej/Bo6ywL+QHNzw0QifPZAJ1sdx+u8r/4xhLepgfejmyLaTGb6mA+w27EglaPq0x CWVQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=OCcxFZ8u217pCLU2+Z7QXQBb4BZSJxt773aXmFVctu0=; b=T4mHdbOVqovq87SN7kBTDMhH7oTq5tWSmCCaBVXoG8ySEuUsTCzT1s7sr26tx9IS4D kaYxlNjKrue7Z5pOv5HNUe+2m7KykFD4BQCx+X958H84Os5v/jqCrLBBVX7ijAydJPXw EwS+7stUaZv/cPeagBUAui6aUqE2W/llPgNmn5ceOOn1ZcTnV4Q73OKf2clAAKIVuLkJ ZzHDx5aADEIGpajiP7fKaxVV1ezkZYoN9yrqQnDNdLzXq0rXOijUQ1Ae/MwMggbCF7Dy 6BAVqceeumcwKtDNe0BlbaOr0YQUZSnDMtTGKW/f4YI0ympyP16xjU5WAHv/9xhyLGRL HSvg== X-Gm-Message-State: APjAAAVdZhlb5Ac52RcO18tPJmaOyT+LJNmEuSiARA+oMiNr7eeEaeoG bHcwzhLGajMauTnTvuikgCJEVQ== X-Google-Smtp-Source: APXvYqzmvaIMZDp1UqMAki93ZF1pRBJmeuDwiABNRTGvkxZYkz5jfP7bem/APo11T1JcRZhC4F5UYQ== X-Received: by 2002:a62:164f:: with SMTP id 76mr100964441pfw.172.1558573038480; Wed, 22 May 2019 17:57:18 -0700 (PDT) Received: from trong0.mtv.corp.google.com ([2620:0:1000:1601:acd:159c:264f:41eb]) by smtp.gmail.com with ESMTPSA id d13sm23716909pfh.113.2019.05.22.17.57.17 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 22 May 2019 17:57:17 -0700 (PDT) From: Tri Vo To: linux@armlinux.org.uk, yamada.masahiro@socionext.com Cc: ndesaulniers@google.com, stefan@agner.ch, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Tri Vo Subject: [PATCH] ARM: disable FUNCTION_TRACER when building with Clang Date: Wed, 22 May 2019 17:56:57 -0700 Message-Id: <20190523005657.170008-1-trong@android.com> X-Mailer: git-send-email 2.21.0.1020.gf2820cf01a-goog MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Clang needs "-meabi gnu" flag to emit calls to "__gnu_mcount_nc". Otherwise, it inserts calls to undefined "mcount". kernel/softirq.o: In function `_local_bh_enable': ... undefined reference to `mcount' "-meabi gnu" resolves link failures. However, Clang does not implement calls to "__gnu_mcount_nc" correctly. It does not save the link register on the stack, which corrupts the stack. The resulting kernel does not boot. Disable FUNCTION_TRACER support when building with Clang. Link: https://github.com/ClangBuiltLinux/linux/issues/35 Suggested-by: Stefan Agner Signed-off-by: Tri Vo --- arch/arm/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 8869742a85df..7a1804392795 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -75,7 +75,7 @@ config ARM select HAVE_EXIT_THREAD select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL select HAVE_FUNCTION_GRAPH_TRACER if !THUMB2_KERNEL && !CC_IS_CLANG - select HAVE_FUNCTION_TRACER if !XIP_KERNEL + select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !CC_IS_CLANG select HAVE_GCC_PLUGINS select HAVE_HW_BREAKPOINT if PERF_EVENTS && (CPU_V6 || CPU_V6K || CPU_V7) select HAVE_IDE if PCI || ISA || PCMCIA -- 2.21.0.1020.gf2820cf01a-goog