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 EFA0B46D558; Mon, 5 Oct 2026 12:08:21 +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=1791202103; cv=none; b=KbeReBeIAq5I19CR53PfOV3QCfVbxPnCINtOS0G+/7vO8nddW37VYFIUcD/uU8hcI3uXqL40GMLNrnd2YrVb8m4AP70QLXRy1yTPawle5MDgbXzGAu/mZkayEL1IuYDWc7JpbEqtmLMZFOc+EN7CUgdHvStrlskz9Z1fNGb55SA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791202103; c=relaxed/simple; bh=yZQ6MQkJUUodfAS7nSlsKzC1XUxSwzYOyiw/wkJHPxw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=D/6cqU6iC83Pcgc5q3hnpn0bZFLP0tL4vo0rBKKceEDArGyXFme1bgTGTcXSV21uBF27BWGyJhahLYn3otEO2SSYNF//sjKisaRghANNI5AStjiMd73MZ5WvfKD3iahTjhZ7gCHUboKevUceXg2ZSau3Jlletpj9Nvz1pvEdYr4= 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=eZ2XT5Bh; dkim=permerror (0-bit key) header.d=mainlining.org header.i=@mainlining.org header.b=4fNx8f8p; 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="eZ2XT5Bh"; dkim=permerror (0-bit key) header.d=mainlining.org header.i=@mainlining.org header.b="4fNx8f8p" DKIM-Signature: v=1; a=rsa-sha256; s=202507r; d=mainlining.org; c=relaxed/relaxed; h=Message-ID:Date:Subject:To:From; t=1791201962; bh=UyE2WbqxID6O1bGrrpnC3dh LKyhQZ5MZNS++hKSonwE=; b=eZ2XT5Bh4pXDtA40DlRj0lsF7MM3PQxbEpumAS8ocLlYGKCpBh Onu1KggTJSFIP63bAJ3GV4GjZDdY+q/CwNpMAMIr25H8f4WS6hnIsnCfFZVGkbQrTBlYkPBPtYv pkDrle8XJRHWS1Tu2bPND0bxnKRaeoo7efvNSGvAlXWgem4IcsdZwGQ4z5N/bHwI+vjEJ06nJ+1 uXN8fP2rLAYFAOmrL6v40zx4nAEVt9hJm/1WXxTzQb6RVZbG4Qlc77YlmIyhGb4oYmGiDo0q7St ypMDw1C9AXDUxI+PTPaH1jxY6hXMBBs7ohriLVC7nghSPWC8XfVHG1iBVwWHNQVDvCw==; DKIM-Signature: v=1; a=ed25519-sha256; s=202507e; d=mainlining.org; c=relaxed/relaxed; h=Message-ID:Date:Subject:To:From; t=1791201962; bh=UyE2WbqxID6O1bGrrpnC3dh LKyhQZ5MZNS++hKSonwE=; b=4fNx8f8psYphS2ELO4DamDMhCz7KzrLNPkKLK5GgxIU8P6GdKk tdaM6pSLX+q1NGmVNr7INXgUzQwffOmwUCCA==; 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 2/3] csky: Emulate two-byte cmpxchg Date: Mon, 5 Oct 2026 12:05:55 +0000 Message-ID: <20261005120556.383004-3-brads@mainlining.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261005120556.383004-1-brads@mainlining.org> References: <20261005120556.383004-1-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 C-SKY has no two-byte atomic compare and swap, so the __cmpxchg() macros let case 2 fall through to BUILD_BUG() via default, and a two-byte cmpxchg() fails the build. Route case 2 through the new cmpxchg_emu_u16(), which narrows the old and new values itself, so all three orderings, relaxed, acquire and full, keep the (uintptr_t) casts the case 1 path already uses. Signed-off-by: Bradley Morgan --- arch/csky/include/asm/cmpxchg.h | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/csky/include/asm/cmpxchg.h b/arch/csky/include/asm/cmpxchg.h index db6dda47184e..6f3ca79e54ac 100644 --- a/arch/csky/include/asm/cmpxchg.h +++ b/arch/csky/include/asm/cmpxchg.h @@ -64,6 +64,9 @@ switch (size) { \ case 1: \ __ret = (__typeof__(*(ptr)))cmpxchg_emu_u8((volatile u8 *)__ptr, (uintptr_t)__old, (uintptr_t)__new); \ + break; \ + case 2: \ + __ret = (__typeof__(*(ptr)))cmpxchg_emu_u16((volatile u16 *)__ptr, (unsigned long)__old, (unsigned long)__new); \ break; \ case 4: \ asm volatile ( \ @@ -97,6 +100,9 @@ switch (size) { \ case 1: \ __ret = (__typeof__(*(ptr)))cmpxchg_emu_u8((volatile u8 *)__ptr, (uintptr_t)__old, (uintptr_t)__new); \ + break; \ + case 2: \ + __ret = (__typeof__(*(ptr)))cmpxchg_emu_u16((volatile u16 *)__ptr, (unsigned long)__old, (unsigned long)__new); \ break; \ case 4: \ asm volatile ( \ @@ -131,6 +137,9 @@ switch (size) { \ case 1: \ __ret = (__typeof__(*(ptr)))cmpxchg_emu_u8((volatile u8 *)__ptr, (uintptr_t)__old, (uintptr_t)__new); \ + break; \ + case 2: \ + __ret = (__typeof__(*(ptr)))cmpxchg_emu_u16((volatile u16 *)__ptr, (unsigned long)__old, (unsigned long)__new); \ break; \ case 4: \ asm volatile ( \ -- 2.53.0