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 5871447ECEE; Mon, 5 Oct 2026 12:09:39 +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=1791202181; cv=none; b=E8Gluzbgl0DDSkpkg61VHnERY7VXtfnjvFyYuO8KYDUCIDlmp6mTEYanVcM+weJBxxSbFPirCQJ6FHjUdhmzIk36KFmmF0ta+g7JXMnQBJ1IKQeu0k4uQV1nBej4UxFKwoaICzjYH1fxG4JlHKKZdTenDRhfqPJzNP1vB8KIimc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791202181; c=relaxed/simple; bh=i0KnUM5v5QJil826Tj60TG6RtCKz0NN6pVnBO8O6ys0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=sP6UpufqbHVTiCIswHxfwDKWIInkmiKgr5KxSvFeKrXQyZRBihETysuHItTUVoA5LpgjfbK8dS8azDG5/LXZbkc1Q7IxDgqMloV5/uj1GHuj2JHSF2aKur5U3x6jeVc1H44GmdqeI2FUYFnGioJvj5mHAAtgyzwcffmqKng/Y5M= 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=QHNr5c5q; dkim=permerror (0-bit key) header.d=mainlining.org header.i=@mainlining.org header.b=mcknjMa6; 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="QHNr5c5q"; dkim=permerror (0-bit key) header.d=mainlining.org header.i=@mainlining.org header.b="mcknjMa6" DKIM-Signature: v=1; a=rsa-sha256; s=202507r; d=mainlining.org; c=relaxed/relaxed; h=Message-ID:Date:Subject:To:From; t=1791202029; bh=gQiGga2Z4THQxcURrzEPZFq KmnssVIT4dSdk9XOrkDQ=; b=QHNr5c5qIAmqgf0Jg4cLlc4G7QeEf399sVt4/klQd6SKIIvkK6 nyi6UmrLViMTLLyOaSFa7rcHgFEJ+f7F3k5E90pCchPRP2fAlRKUsj+SA9lAtABNtav+1c1ePE5 mCfM/+bKOXgiLIMojUNiFd5+SAcJ+aTcAXrKEHTOnG/CXFD/gt/QOy0v/atGSx88o2I8ziXh0KH cTbREZhenoWllakpzaPpU82kjdMTwIuV2EclJjGtCkaScwIM5MzeNQqkKMHhC5lhNo5q5PGUK7A b8RalTwd0nKAOcDFFz6GQZdb2ZYZb5k4LdK4i/o5BYuej8VxI7IB+VEYRbevoZyWJ/A==; DKIM-Signature: v=1; a=ed25519-sha256; s=202507e; d=mainlining.org; c=relaxed/relaxed; h=Message-ID:Date:Subject:To:From; t=1791202029; bh=gQiGga2Z4THQxcURrzEPZFq KmnssVIT4dSdk9XOrkDQ=; b=mcknjMa6g1qXxOX73WK05b9KC15T1QWLZINnCB5eQt1XWW1xm8 KC+7pqBXNuSHPNb6uewCj1iwVwfP8YV0rqAA==; From: Bradley Morgan To: akpm@linux-foundation.org, vgupta@kernel.org, guoren@kernel.org, chris@zankel.net, jcmvbkbc@gmail.com Cc: arnd@arndb.de, paulmck@kernel.org, david.laight.linux@gmail.com, glaubitz@physik.fu-berlin.de, ysato@users.sourceforge.jp, dalias@libc.org, linux-snps-arc@lists.infradead.org, linux-csky@vger.kernel.org, linux-kernel@vger.kernel.org, brads@mainlining.org Subject: [PATCH v5 3/3] xtensa: Emulate two-byte cmpxchg Date: Mon, 5 Oct 2026 12:07:00 +0000 Message-ID: <20261005120700.383058-4-brads@mainlining.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261005120700.383058-1-brads@mainlining.org> References: <20261005120700.383058-1-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 Xtensa has no two-byte atomic compare and swap, so the __cmpxchg() switch 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 the old and new values as unsigned long and narrows them itself, so the call needs no extra casts. Signed-off-by: Bradley Morgan --- arch/xtensa/include/asm/cmpxchg.h | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/xtensa/include/asm/cmpxchg.h b/arch/xtensa/include/asm/cmpxchg.h index b6db4838b175..8dea8e357fc0 100644 --- a/arch/xtensa/include/asm/cmpxchg.h +++ b/arch/xtensa/include/asm/cmpxchg.h @@ -76,6 +76,7 @@ __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size) { 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); default: __cmpxchg_called_with_bad_pointer(); return old; -- 2.53.0