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 E099343E4A2; Wed, 16 Sep 2026 20:02:34 +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=1789588968; cv=none; b=lpac5oVIwpVM9k4KvsgxgpnFo0erk8PYRnGqZ/agJpb10lnRByL/UhwDuP+gby02pFdtAn/Lcv1qBKftawGN9bLqNRz7kHvLv/OaNpn1xFTdZQ0PaDSkOA2XsBaMcVdOKJ1KWv51P5hquu5PMMQx0VC6DtbaG8PHmmRgmf2Eh2I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789588968; c=relaxed/simple; bh=CnPQk5xHz0wKRKYP2fkyD+/dsIdYEO5cOQ4XeQu+MWo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=id4VXdAilOya2FDt6r6cGb5b2clLoGKvL7nLItLgNWUEJbCrOxm4We0S1EBexIiVZnC1eYkdfnoVWREb5DBQQMvUW3tZJkMi1AXfLUUFe3FQR0HFvoUeUfUXQsDDq+N/RwaqT7JYUhlRGGhnign6dA2RHSerFDlcf70pEMnddv4= 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=l73A9EjS; dkim=permerror (0-bit key) header.d=mainlining.org header.i=@mainlining.org header.b=c/LfVz7t; 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="l73A9EjS"; dkim=permerror (0-bit key) header.d=mainlining.org header.i=@mainlining.org header.b="c/LfVz7t" DKIM-Signature: v=1; a=rsa-sha256; s=202507r; d=mainlining.org; c=relaxed/relaxed; h=Message-ID:Date:Subject:To:From; t=1789588936; bh=RgSuWwdEtSR5tNlSbUFwtN1 6+B/ED9O57B5SFsv+Sao=; b=l73A9EjSO6yR6WdliduzVn1CIfORqheLdIQdtdeLPAZWyxa11E 0EpQWuNSbKcVrw6PeoDKKdoWN+1GVE9Y3rUy61FOsYrMa6HlNwD5eFBP/TP3STbRo5rOM15u0fY eidU56394BfiA2yBlM5yUYZEVUwCri+GzP55lMhuMNqYZF23VD1XlvH+ZNUXSp/NAme1jN8dn/d WQ2vxtBU2pLRQkqx12FsrNhBILKg59O6X61+8Xr1psbu/fpKurkzCb+rJn0m03Gkgwvq+cPHdpZ sYpRIl7fzRzn6hw/P8r+DoiAg72kDqixBXDxYCFvYlf6IvbNFBDlunD7/F4ulbwfOWA==; DKIM-Signature: v=1; a=ed25519-sha256; s=202507e; d=mainlining.org; c=relaxed/relaxed; h=Message-ID:Date:Subject:To:From; t=1789588936; bh=RgSuWwdEtSR5tNlSbUFwtN1 6+B/ED9O57B5SFsv+Sao=; b=c/LfVz7tNPTCmaPlbh3i+J7cFoigXYI7S5Rs8blqt5qqX61PKQ yrpQBKSCbiZBXokixP1nlTHs/FbUvzFV2UDQ==; 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 v2 4/5] sh: Emulate two-byte cmpxchg Date: Wed, 16 Sep 2026 20:02:14 +0000 Message-ID: <20260916200215.21774-5-brads@mainlining.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260916200215.21774-1-brads@mainlining.org> References: <20260916200215.21774-1-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 SH has no byte or halfword atomic memory operations, so the __cmpxchg() switch routes case 1 through cmpxchg_emu_u8() and lets case 2 fall through to __cmpxchg_called_with_bad_pointer(), which is declared but never defined, so a two-byte cmpxchg() fails at link time. Route case 2 through the new cmpxchg_emu_u16(), which takes natural u16 arguments, so the unsigned long old and new narrow at the function boundary. Acked-by: John Paul Adrian Glaubitz Signed-off-by: Bradley Morgan --- arch/sh/include/asm/cmpxchg.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/sh/include/asm/cmpxchg.h b/arch/sh/include/asm/cmpxchg.h index 1e5dc5ccf7bf..477d3025a441 100644 --- a/arch/sh/include/asm/cmpxchg.h +++ b/arch/sh/include/asm/cmpxchg.h @@ -59,6 +59,8 @@ static inline unsigned long __cmpxchg(volatile void * ptr, unsigned long old, switch (size) { case 1: return cmpxchg_emu_u8(ptr, old, new); + case 2: + return cmpxchg_emu_u16(ptr, old, new); case 4: return __cmpxchg_u32(ptr, old, new); } -- 2.47.3