From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from outpost1.zedat.fu-berlin.de (outpost1.zedat.fu-berlin.de [130.133.4.66]) (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 0BF934EFFC4; Thu, 15 Oct 2026 09:29:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=130.133.4.66 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792056546; cv=none; b=kvQKQDdp9fsWQhQoJaDXZURCTuRU3Y4NJY4P2n1ad93vbJ7VapoFWQnj8RrpE4w/pUyRktD6BQPMHMdkL8cByxMHt+QkCVTmXQT1UXbMwQsvq2pijqAFXL9NSwWtDxRGDLSVYhVOQzkPkOEf+igcR2bX6eTYEs6fRtJ56836Kpo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792056546; c=relaxed/simple; bh=NSqNR+ngoZZw0eODXMM7eM0Krmpuk5J5E1Muf3YGwzE=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=VChdNYmjohSXdxNM4rnCxi73I0KLDO7J/eURVT2SmOit/UnStDf/kR17AY5XMAIgtnZI8QMZ1UNeqcmjPEbeyPFpPctUmGSu+I169rB2L5CFLae6YY/Oy79mjqwJSC/y4Baa/hbO+V+Y/6n5ql69eeJtnIlZBbkHy7dy/xrg3ss= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=physik.fu-berlin.de; spf=pass smtp.mailfrom=zedat.fu-berlin.de; dkim=pass (2048-bit key) header.d=fu-berlin.de header.i=@fu-berlin.de header.b=HlKVv/7V; arc=none smtp.client-ip=130.133.4.66 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=physik.fu-berlin.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zedat.fu-berlin.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=fu-berlin.de header.i=@fu-berlin.de header.b="HlKVv/7V" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=fu-berlin.de; s=fub01; h=MIME-Version:Content-Transfer-Encoding: Content-Type:References:In-Reply-To:Date:Cc:To:From:Subject:Message-ID:From: Reply-To:Subject:Date:Message-ID:To:Cc:MIME-Version:Content-Type: Content-Transfer-Encoding:Content-ID:Content-Description:In-Reply-To: References; bh=jZxueYXNwc1g9ouJPv18Fw9eXntISx5E+iCNK1BHUXI=; t=1792056541; x=1792661341; b=HlKVv/7VU9djDiiPqGTrLqEXE0+adkjDsGmpGVwfnyPluS8goFDMjrnXzcW+l fMTj1JSbawoFYZ6Kqi9c8eLzx4qBJ0PERfeUWiwr/0YWYsA6bpxSp5SsZfe+l6Bw/d99/dxzb3t8P FAlDcnSDgsJrlHw8TWXdwwYPd7eJk1SPQnD/Zb0Egc3vlyfrCPihNZrEBzpDzn6FXYePrq0yP/gyB FtWbYwZmBUxQazTNQCtLsX/5Fi/oS1cRkYTCv3YLeAUrP+o0uZ+GI3sse6t94EV9R/zPyJshxtAet VOCx7uODcJI7d1/25PbFMGk4oEiEg8bvVMjdCIWPNpgzDmPpjg==; Received: from inpost2.zedat.fu-berlin.de ([130.133.4.69]) by outpost.zedat.fu-berlin.de (Exim 4.100) with esmtps (TLS1.3) tls TLS_AES_256_GCM_SHA384 (envelope-from ) id 1xHHlY-000000031kz-1E1P; Thu, 15 Oct 2026 11:28:48 +0200 Received: from p5b13a90a.dip0.t-ipconnect.de ([91.19.169.10] helo=[192.168.178.61]) by inpost2.zedat.fu-berlin.de (Exim 4.100) with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (envelope-from ) id 1xHHlY-00000003EdM-0H7L; Thu, 15 Oct 2026 11:28:48 +0200 Message-ID: Subject: Re: [PATCH 3/4] sparc32: implement futex atomics, with casa detected at run time From: John Paul Adrian Glaubitz To: Arnd Bergmann , Ramin Moussavi , Andreas Larsson , "David S . Miller" Cc: Thomas Gleixner , Peter Zijlstra , Guenter Roeck , sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org, Imre Kaloz Date: Thu, 15 Oct 2026 11:28:47 +0200 In-Reply-To: <7334b77c-2ec7-4678-8296-f187e0304f49@app.fastmail.com> References: <20261015085545.3246951-1-ramin.moussavi@yacoub.de> <20261015085545.3246951-4-ramin.moussavi@yacoub.de> <7334b77c-2ec7-4678-8296-f187e0304f49@app.fastmail.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.60.2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Original-Sender: glaubitz@physik.fu-berlin.de X-ZEDAT-Hint: PO On Thu, 2026-10-15 at 11:23 +0200, Arnd Bergmann wrote: > On Thu, Oct 15, 2026, at 10:55, Ramin Moussavi wrote: > > sparc32 has no futex_atomic_cmpxchg_inatomic() or > > arch_futex_atomic_op_inuser() of its own. The generic versions only > > work on UP, so FUTEX depends on !(SPARC32 && SMP) and an SMP kernel > > has no futexes at all; NPTL cannot run on it. >=20 > I believe there are existing patches for LEON with CASA that > should just be merged, I would not worry about supporting broken > CPUs that never had this. I think you mean the series by Imre Kaloz [1]? If yes, he actually implements CASA emulation unless I'm missing something. Adrian > [1] https://lore.kernel.org/sparclinux/20260927005821.8369-1-kaloz@kernel= .org/ --=20 .''`. John Paul Adrian Glaubitz : :' : Debian Developer `. `' Physicist `- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913