From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-186.mta0.migadu.com (out-186.mta0.migadu.com [91.218.175.186]) (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 5DA37A92E for ; Thu, 20 Nov 2025 07:46:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.186 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763624772; cv=none; b=atGwrCIqxnb5xbWW2nDH5p6MloPCl1Hilt9N5lJoEj8O+yV8edruScLIET7gOZ5ZayWHKo7DB3FbqJaloRivwc2PU8YqKObLWzBORbve/l/n3A23JJ81YnNmc1ErZbjSbeTBiTs/Nk86vq6emgBKDRRm8fFxA0bimZOaKze22qw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763624772; c=relaxed/simple; bh=p5XiOVhym3OuRZaS8Dmic/3wN5baDwTiofnmYEQWhFs=; h=From:Subject:Date:Message-Id:MIME-Version:Content-Type:To:Cc; b=ILSfKVl2cjbFDvgSmbxT7HWQbJhD5sn2PbVEHbRIGjbIU5jCVpDyEU5eVA9TzkH4IrH0gwQFDenXFAIZvMy3bJ2B2riPSGKqyOYQIVub6yjkdVGgakYG0++ZTta2VNXzx6GPr9IdlzM1YF0VzG9JtlJRqAxbJpkFwlDcaXhk3Mk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=MdYHbV73; arc=none smtp.client-ip=91.218.175.186 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="MdYHbV73" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1763624764; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=09ux0ObWAtSprUQ6j3/PUauALBoIBJ5o1DLyjVAcnmE=; b=MdYHbV73QqectavjlUz6Oran7dLON82jn+wytINAEJLNW9wElw5jHDRyVj9DIozsbVXkvZ JWVmuUfZv+QJPPcJ/OBb043YoNcDUyKmzzOQog/9pR3Tj6K2Ch6DBVOZDS12nntA63yQyE TtMDF5amUIUUaocFf4gwnUXaXAUOM/k= From: George Guo Subject: [PATCH 0/2] LoongArch: Add 128-bit atomic cmpxchg support Date: Thu, 20 Nov 2025 15:45:43 +0800 Message-Id: <20251120-2-v1-0-705bdc440550@linux.dev> Precedence: bulk X-Mailing-List: loongarch@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-B4-Tracking: v=1; b=H4sIACfHHmkC/6tWKk4tykwtVrJSqFYqSi3LLM7MzwNyDHUUlJIzE vPSU3UzU4B8JSMDI1NDQyMDXSPdFANjCzOjJKPkNLMUJaC6gqLUtMwKsBnRsbW1AEnU8gpTAAA A X-Change-ID: 20251120-2-d03862b2cf6d To: Huacai Chen , WANG Xuerui Cc: loongarch@lists.linux.dev, linux-kernel@vger.kernel.org, George Guo , George Guo X-Developer-Signature: v=1; a=ed25519-sha256; t=1763624762; l=1549; i=dongtai.guo@linux.dev; s=20251103; h=from:subject:message-id; bh=p5XiOVhym3OuRZaS8Dmic/3wN5baDwTiofnmYEQWhFs=; b=Dn8lBiHYsgDoL8T0usGs/CJIKfGmFjfk3Dprs8qdI0imt/QqSqQq7kSJXHonqODqIgmdlUL8W JZrEM0W1QrgD2HBjQaKragVga8Vd9NzqVm1v5rfyorPFBEH7RmA4GqP X-Developer-Key: i=dongtai.guo@linux.dev; a=ed25519; pk=yHUJPGx/kAXutP/NSHpj7hWW0KQNlv3w9H6ju4qUoTM= X-Migadu-Flow: FLOW_OUT This patch series adds 128-bit atomic compare-and-exchange support for LoongArch architecture, which fixes BPF scheduler test failures caused by missing 128-bit atomics support. The series consists of two patches: 1. "LoongArch: Add 128-bit atomic cmpxchg support" - Implements 128-bit atomic compare-and-exchange using LoongArch's LL.D/SC.Q instructions - Fixes BPF scheduler test failures (scx_central scx_qmap) where kmalloc_nolock_noprof returns NULL due to missing 128-bit atomics, leading to -ENOMEM errors during scheduler initialization 2. "LoongArch: Enable 128-bit atomics cmpxchg support" - Adds select HAVE_CMPXCHG_DOUBLE and select HAVE_ALIGNED_STRUCT_PAGE in Kconfig to enable 128-bit atomic cmpxchg support The issue was identified through BPF scheduler test failures where scx_central and scx_qmap schedulers would fail to initialize. Testing was performed using the scx_qmap scheduler from tools/sched_ext/, confirming that the patches resolve the initialization failures. Signed-off-by: George Guo --- George Guo (2): LoongArch: Add 128-bit atomic cmpxchg support LoongArch: Enable 128-bit atomics cmpxchg support arch/loongarch/Kconfig | 2 ++ arch/loongarch/include/asm/cmpxchg.h | 46 ++++++++++++++++++++++++++++++++++++ 2 files changed, 48 insertions(+) --- base-commit: 8b690556d8fe074b4f9835075050fba3fb180e93 change-id: 20251120-2-d03862b2cf6d Best regards, -- George Guo