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[23.128.96.18]) by mx.google.com with ESMTP id p24si4127242ejy.672.2021.01.28.22.25.17; Thu, 28 Jan 2021 22:25:42 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@suse.com header.s=susede1 header.b=Kqo2SaoB; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=QUARANTINE sp=NONE dis=NONE) header.from=suse.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231909AbhA2GYR (ORCPT + 99 others); Fri, 29 Jan 2021 01:24:17 -0500 Received: from mx2.suse.de ([195.135.220.15]:44508 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229459AbhA2GYM (ORCPT ); Fri, 29 Jan 2021 01:24:12 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1611901405; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=x55Ghkb1NGSakCxiseBfr9GEKcsGjHRMccE0zQUExb0=; b=Kqo2SaoBr7vMKdT9ZC0xKlF/TuUvQQtxU7kuYFdaUkUFB+4cRlueU1az7KIA84wsAOr26E uulsVmbtscSVNLwtcRN5EA+sFUxGDTd8oqKvoAhXxIBTw3lRCwcgDk/WTmKLm8XohgyaWS fP/8/VpGk/oxou+u4EtDPdXE6RXuaLk= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 196EAABDA; Fri, 29 Jan 2021 06:23:25 +0000 (UTC) Subject: Re: [PATCH] x86: Disable CET instrumentation in the kernel To: Josh Poimboeuf , x86@kernel.org Cc: Masami Hiramatsu , Masami Hiramatsu , Peter Zijlstra , LKML , Alexei Starovoitov , bpf@vger.kernel.org, Steven Rostedt References: <25cd2608-03c2-94b8-7760-9de9935fde64@suse.com> <20210128001353.66e7171b395473ef992d6991@kernel.org> <20210128002452.a79714c236b69ab9acfa986c@kernel.org> <20210128103415.d90be51ec607bb6123b2843c@kernel.org> <20210128123842.c9e33949e62f504b84bfadf5@gmail.com> <20210128165014.xc77qtun6fl2qfun@treble> <20210128215219.6kct3h2eiustncws@treble> From: Nikolay Borisov Autocrypt: addr=nborisov@suse.com; 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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210128215219.6kct3h2eiustncws@treble> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 28.01.21 г. 23:52 ч., Josh Poimboeuf wrote: > > With retpolines disabled, some configurations of GCC will add Intel CET > instrumentation to the kernel by default. That breaks certain tracing > scenarios by adding a superfluous ENDBR64 instruction before the fentry > call, for functions which can be called indirectly. > > CET instrumentation isn't currently necessary in the kernel, as CET is > only supported in user space. Disable it unconditionally. > > Reported-by: Nikolay Borisov > Signed-off-by: Josh Poimboeuf Tested-by: Nikolay Borisov Reviewed-by: Nikolay Borisov