From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.mainlining.org (mail.mainlining.org [5.75.144.95]) (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 1D49E4F4CED; Thu, 17 Sep 2026 16:40:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=5.75.144.95 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789663259; cv=none; b=K9kEhNKadyQiJc6itRmYmzFexGxqSrRDj5dKiHfdn3bmv5FlznYbiHu+ghC5U75CoWhgTatume8WiDVWd9EX5x++sTrweYcBiHFID2+X9IAYGfog9pV4jd7qvzWlP2/Qt+wJKgD3oqGMoYG689y48m/3jxNc9y59tdLGnxIdElo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789663259; c=relaxed/simple; bh=qFn7dLToUkvIgv0m6saPs5B0Agok+SF6dJ4kaifw88U=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=W3RWcTb1s4GloAFvvxKoFO1lTzns7BHf2CWxq/AfgoFcq3jJEj1vStG6/hIBOypLV2YZh6o4r0Tm5Ctz7C2N9YuVeggy3HMH9q1/nkdlYt63ckOTMJJ+fdDwX+CrT4rj0fYhtrRSv6FUg7wsODrl51/3G3OL1JFx/Tw+eMH5SaE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=mainlining.org; spf=pass smtp.mailfrom=mainlining.org; dkim=pass (2048-bit key) header.d=mainlining.org header.i=@mainlining.org header.b=rJO3Ncd/; dkim=permerror (0-bit key) header.d=mainlining.org header.i=@mainlining.org header.b=1W+mBsO/; arc=none smtp.client-ip=5.75.144.95 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=mainlining.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mainlining.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=mainlining.org header.i=@mainlining.org header.b="rJO3Ncd/"; dkim=permerror (0-bit key) header.d=mainlining.org header.i=@mainlining.org header.b="1W+mBsO/" DKIM-Signature: v=1; a=rsa-sha256; s=202507r; d=mainlining.org; c=relaxed/relaxed; h=Message-ID:Date:Subject:To:From; t=1789663110; bh=aoBMHO5+/N93x6VJ0ikS7kV mlAkKZm9tlGAN4/+qBSY=; b=rJO3Ncd/TnwsSG6RKws52boGwVzJTIPvSJEp4C7cL4OTLvpZqN IeFlOtZKzBFgxVuy03X79ASjrTRcxSsaBaD9ZdJTxYTO0Sierje8pTwulB9tiUTFE2kuMV4XHQk XE82T6ODkRn5X2pqSoOl3W5l5cOQQn5TOT48lwwWroD3Vt/yLF2+Wf7O+/ohZ8pz6AXLBx9CoF2 FnR/Eylo5MjcHXjnT3NVHCcFMC7Z6gpgTF+4Lgu/K3KhQynA7F1Ttxb7PQmRf0TucjKBUzr7wvb H9lCObzaTfulg5yPgAF4gXSyoJ4OLQDlj4KxJmDr/tWhzqb+K/p4xnksRCWK8fPJ4Pw==; DKIM-Signature: v=1; a=ed25519-sha256; s=202507e; d=mainlining.org; c=relaxed/relaxed; h=Message-ID:Date:Subject:To:From; t=1789663110; bh=aoBMHO5+/N93x6VJ0ikS7kV mlAkKZm9tlGAN4/+qBSY=; b=1W+mBsO/mmKw5OVcobpC6PP5Ha7M073LKARMu5sMFMTpULj9s4 M4vkGskgCo9QyIECUmxAYNPQ1IJNLExTN4BQ==; From: Bradley Morgan To: Andrew Morton , Vineet Gupta , Guo Ren , Yoshinori Sato , Rich Felker , Chris Zankel , Max Filippov Cc: Arnd Bergmann , "Paul E . McKenney" , David Laight , John Paul Adrian Glaubitz , linux-snps-arc@lists.infradead.org, linux-csky@vger.kernel.org, linux-sh@vger.kernel.org, linux-kernel@vger.kernel.org, Bradley Morgan Subject: [PATCH v3 2/5] ARC: Emulate two-byte cmpxchg Date: Thu, 17 Sep 2026 16:38:27 +0000 Message-ID: <20260917163830.3748-3-brads@mainlining.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260917163830.3748-1-brads@mainlining.org> References: <20260917163830.3748-1-brads@mainlining.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit ARC has no two-byte atomic compare and swap, so the __cmpxchg() macro switch lets case 2 fall through to BUILD_BUG() via default. Route case 2 through the new cmpxchg_emu_u16(), which takes the old and new values as unsigned long and narrows them itself, so the (uintptr_t) casts on _o_ and _n_ are no longer needed and the case 2 call passes them straight. Signed-off-by: Bradley Morgan --- arch/arc/include/asm/cmpxchg.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arc/include/asm/cmpxchg.h b/arch/arc/include/asm/cmpxchg.h index 76f43db0890f..9b48b8fe0db2 100644 --- a/arch/arc/include/asm/cmpxchg.h +++ b/arch/arc/include/asm/cmpxchg.h @@ -50,6 +50,9 @@ case 1: \ _prev_ = (__typeof__(*(ptr)))cmpxchg_emu_u8((volatile u8 *__force)_p_, (uintptr_t)_o_, (uintptr_t)_n_); \ break; \ + case 2: \ + _prev_ = (__typeof__(*(ptr)))cmpxchg_emu_u16((volatile u16 *__force)_p_, (uintptr_t)_o_, (uintptr_t)_n_); \ + break; \ case 4: \ _prev_ = __cmpxchg(_p_, _o_, _n_); \ break; \ -- 2.47.3