From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta-03.yadro.com (mta-03.yadro.com [89.207.88.253]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 07CFB1F707A; Tue, 3 Dec 2024 14:44:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=89.207.88.253 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733237079; cv=none; b=DPIQqETwQhsdo2pzce9AwUNwEKlYLCLu4u5lbKT84KLkBGpkL063EwsVxDt8FgqVQ/fW8dPDZS5580E+pBibILkEP+DlcpCvQOwqYTDgeVi0Uya9T0NBFV8D1ISohTcWeSdA14IBPDVvGhuCPWX9CUSP4lEtlDJpVp/IVbH0AFs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733237079; c=relaxed/simple; bh=j+1Z523yN4c3k35sEz8WLWeR9a0Tote+0vlm4AhrGg4=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=a+MxjVCVf7JauTTt3grRcKyo8NCfxoNZGdxdhySlyS1fz/t1ftQgty1jicW8BoKM4dUGrJBN1Zkz/THTf9NPx8Qz1hSe6JLW/8m4KrVqmUZVmKqmNmslYc6Sl7oQBW9QWXOC70Jwm/im5HtSIrbx4pSv4TCa+q4zUMLqynUx7M8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=yadro.com; spf=pass smtp.mailfrom=yadro.com; dkim=pass (2048-bit key) header.d=yadro.com header.i=@yadro.com header.b=F/xs/DWx; dkim=pass (2048-bit key) header.d=yadro.com header.i=@yadro.com header.b=fWTohsPr; arc=none smtp.client-ip=89.207.88.253 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=yadro.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=yadro.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=yadro.com header.i=@yadro.com header.b="F/xs/DWx"; dkim=pass (2048-bit key) header.d=yadro.com header.i=@yadro.com header.b="fWTohsPr" DKIM-Filter: OpenDKIM Filter v2.11.0 mta-03.yadro.com 47C23E0002 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yadro.com; s=mta-04; t=1733237067; bh=yZe/rHto/yJINXzpM0VYaXBnEXiTAtPyuKao0ifLMUM=; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type:From; b=F/xs/DWxB9Q2xFJTiRE+BRDiKHj8Xg2JNDNpNKatEFAPn6Sq07CSqnIlkmho4PfwY i4n8ckL5a3UEcYTNOdpkqLXDKZBfkd7+wWE0mfifon8WjKC8MyRJDp03drsPHit5qs YQ9JnPohpFjFSsvMm/cRC4ssbK1H5e16wHHOhNFvdjZdWNGq1Um3S0RFtcZhc9MLLx JI6jMOpobs78O2XmE6kLtD4ZuLeOTprjTa1H/Bj57GLN36L35e6RvCsN1uEfiK+MmH xw0PDm5poqRVGxc5JxpvzQd/rZMdMmLU2C+NBl1lHNHgIe0+HD+RrzjY70tqcVWiiQ 4I9yvZTO/OnBQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yadro.com; s=mta-03; t=1733237067; bh=yZe/rHto/yJINXzpM0VYaXBnEXiTAtPyuKao0ifLMUM=; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type:From; b=fWTohsPr10f9KWPbfxCVvIwt69HevffSbsXqEZwu0WmT/iJSr6Wx4XOMh6Tw4Ad+T q5eZ4Qizq7Ej1Yh2GCmzHd3vuVmhdLUhUkUpFEGb1BNl1+/gC7sjTpWuMv1FRKZXEk lvtHtuet3zGS8CLJjXx3dc/4KJ1DhZTBy7XOFhii3mdZNcrDl+JORThtZRey7sxPIa ElFPQLxavdFMRreKNyLlsIV+jRBOXPYHkmHEGB2PyhLbKxMQihpOo+SnmtNBOSg7a3 SjEGQJVx/l1YViUNgBV2f9s43som2T4UPePX0ueYyz1oFITpw/l1a2GcyHg2MwNnAg Cx9inGVCixcLg== Message-ID: <7e5ce1ce-e30a-46c5-80fb-eb52e59e4dc2@yadro.com> Date: Tue, 3 Dec 2024 17:44:25 +0300 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: Re: [PATCH v3 1/7] riscv: ftrace: support fastcc in Clang for WITH_ARGS To: =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= CC: Bill Wendling , Justin Stitt , Nick Desaulniers , Nathan Chancellor , Albert Ou , Palmer Dabbelt , Paul Walmsley , Mark Rutland , Masami Hiramatsu , Steven Rostedt , Andy Chiu , , , , , , , , , , , , , , , , References: <20241127172908.17149-1-andybnac@gmail.com> <20241127172908.17149-2-andybnac@gmail.com> <87wmghotth.fsf@all.your.base.are.belong.to.us> Content-Language: en-US From: Evgenii Shatokhin In-Reply-To: <87wmghotth.fsf@all.your.base.are.belong.to.us> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: T-Exch-05.corp.yadro.com (172.17.10.109) To T-EXCH-10.corp.yadro.com (172.17.11.60) Hi, On 03.12.2024 15:05, Björn Töpel wrote: > > Andy Chiu writes: > >> From: Andy Chiu >> >> Some caller-saved registers which are not defined as function arguments >> in the ABI can still be passed as arguments when the kernel is compiled >> with Clang. As a result, we must save and restore those registers to >> prevent ftrace from clobbering them. >> >> - [1]: https://reviews.llvm.org/D68559 >> >> Reported-by: Evgenii Shatokhin >> Closes: https://lore.kernel.org/linux-riscv/7e7c7914-445d-426d-89a0-59a9199c45b1@yadro.com/ >> Acked-by: Nathan Chancellor >> Signed-off-by: Andy Chiu > > Fixes tag? As far as I understand it, Ftrace for RISC-V has had this problem since support for FTRACE_WITH_REGS was added. FTRACE_WITH_ARGS inherited it. So, it should probably be as follows: Fixes: aea4c671fb98 ("riscv/ftrace: Add DYNAMIC_FTRACE_WITH_REGS support") It is more of a workaround rather than a fix though, because it is still undecided where the problem is, in the kernel or in LLVM/clang. That discussion went nowhere, unfortunately, so it is better to use a workaround and move on, IMO. > > Reviewed-by: Björn Töpel > Regards, Evgenii