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 3808344237B; Wed, 16 Sep 2026 20:04:41 +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=1789589096; cv=none; b=YptdlyaCQKKRG3rqLpKUNRipFt3pui1QqzaOwmY83kiSK9pQg6VwLvb2waSz9H7DeiZARODQMYDxIoznZUp0h05EsHIPrM/r1BN60QVCub5JtaBHQcCzCFlR8cyt6YedSPujmyP/TG5YhzjCy9epNdKPgsP+uLlNRZCpc6HDj9c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789589096; c=relaxed/simple; bh=q8VUuAMu4loyahpVZ49szfxRv+8c4UDMw+jk/d97UGQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QBklRKvS3exBJ8HIqfe6MlSow0Aug1wW/85+MneBsp1/h87tne7zNB9oiGw7mcvWN5whRRcEgVbdzxPDAbnWo4NRXRIn3dnH12ymIAhUmP2j0+vHp5fN7Ogz59VbfFRe59SKt3tLL3z4iTcZx3gcDQL/6woyIBi2cvPC+AqOzvE= 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=QrcW/ZGs; dkim=permerror (0-bit key) header.d=mainlining.org header.i=@mainlining.org header.b=GUPIOwdm; 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="QrcW/ZGs"; dkim=permerror (0-bit key) header.d=mainlining.org header.i=@mainlining.org header.b="GUPIOwdm" 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=Cmoc+LvxrB8XTyAuxieF0n1 oKRJqDrHiKarYKzS8wOk=; b=QrcW/ZGsGc/8zHko7LRpzYzG2forpReCVNUoEO/bRUiepdOsvJ Vr1/YF1bZ3Bw296iaAHCQclAkdJYIUR6E02L/Nq8tZfvVx22f7rYSWrsMTbLU1cW0SCq8DSeYnN BVg5WtgXATQq/GpIUm611bYcR9qe+DJR5ZKoAs7PnYH1aR23/+8gPaqNZIrUr/UxGocpngHCThG 6HdW+Z51I7gGEhp+ZvlZ1zvFuicUibVeNY7bBLL5ZQc36Yj4a2dB1Cftd463cVKFVEOrAXDUAFN OOPI0h8Jmnqq22PWIuHK9IRam5z0qayaxb78HeVB4twBKIFxpaTu0fnjuLZrjs0ddrw==; 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=Cmoc+LvxrB8XTyAuxieF0n1 oKRJqDrHiKarYKzS8wOk=; b=GUPIOwdm1MvUm482CkvGoF26O4/6Ajr0KBRTAKBF4cQt4KT7lo wqg+pzOKceAgkHmRUcBiSMNVP21Ag6YNpZDg==; 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 5/5] xtensa: Emulate two-byte cmpxchg Date: Wed, 16 Sep 2026 20:02:15 +0000 Message-ID: <20260916200215.21774-6-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 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 natural u16 arguments, so the unsigned long old and new narrow at the function boundary. 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; -- 2.47.3