From patchwork Tue Nov 5 18:30:37 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Haris Okanovic X-Patchwork-Id: 13863350 Received: from smtp-fw-52004.amazon.com (smtp-fw-52004.amazon.com [52.119.213.154]) (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 955D11D2B2C; Tue, 5 Nov 2024 18:31:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=52.119.213.154 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730831505; cv=none; b=aNbGz2Ci/zkITleRJTtfmjjTG8ZQCPXMgLRk/WKv32wpZKbsdM3rvwVJjrUqvJkLOycjZ5pmPTGEtcYqv4nndMqHuQDege+CF5Pw0xr3d8paihc5dgzxW0GwSUEm1WQhdBKR7aMyzAIWe1gsBtap3UM8DtqBxhnJtAWarldV5wU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730831505; c=relaxed/simple; bh=SagvYHKJt5auxGJRJjhhxBCccjHkSwJYzBlZUkeQVJw=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=PIeyGhIQt9urIf/9a3wwRTtKjnPTz5gpOE3+938tvpGPSHb3eVoYgR/ggfjlakQqGbY9GN1o59eUcnVOkpqc2bia2yAJBVHtbDQB8LnupQgXIhGQ4H624LZ+DpdAz82+4fe+lsCYzQAvHEvHTY1NMxmZj1+4HHJd52eZbxu3cpE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com; spf=pass smtp.mailfrom=amazon.com; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b=q4/6g4yV; arc=none smtp.client-ip=52.119.213.154 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="q4/6g4yV" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1730831504; x=1762367504; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=bT6rRx7a7sWccvBSdvoPKKTuXoItJoU+EpMvF26uVsc=; b=q4/6g4yVcoJJcEP3lmqXJIY+zo/mB3ptDXxMj0EdHC9cbw2crAbBM6Rb FL/xqn2Na+EZie6vKU+Vvl4pkLEr+C+yarE8i/hpLf2BTrEeM660eDyBt tQm0n3e6pgVyZDE+gfDkfKolxhj0+T56rBjNwOL9lo5tfnAY/ePOhuebU Q=; X-IronPort-AV: E=Sophos;i="6.11,260,1725321600"; d="scan'208";a="245128567" Received: from iad12-co-svc-p1-lb1-vlan2.amazon.com (HELO smtpout.prod.us-west-2.prod.farcaster.email.amazon.dev) ([10.43.8.2]) by smtp-border-fw-52004.iad7.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Nov 2024 18:31:40 +0000 Received: from EX19MTAUWA001.ant.amazon.com [10.0.21.151:50603] by smtpin.naws.us-west-2.prod.farcaster.email.amazon.dev [10.0.28.125:2525] with esmtp (Farcaster) id 39bb5814-4f48-4caf-ba41-fae750bfbae2; Tue, 5 Nov 2024 18:31:40 +0000 (UTC) X-Farcaster-Flow-ID: 39bb5814-4f48-4caf-ba41-fae750bfbae2 Received: from EX19D001UWA003.ant.amazon.com (10.13.138.211) by EX19MTAUWA001.ant.amazon.com (10.250.64.217) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1258.34; Tue, 5 Nov 2024 18:31:39 +0000 Received: from u34cccd802f2d52.amazon.com (10.106.239.17) by EX19D001UWA003.ant.amazon.com (10.13.138.211) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1258.35; Tue, 5 Nov 2024 18:31:34 +0000 From: Haris Okanovic To: , CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH 1/5] asm-generic: add smp_vcond_load_relaxed() Date: Tue, 5 Nov 2024 12:30:37 -0600 Message-ID: <20241105183041.1531976-2-harisokn@amazon.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20241105183041.1531976-1-harisokn@amazon.com> References: <20240925232425.2763385-1-ankur.a.arora@oracle.com> <20241105183041.1531976-1-harisokn@amazon.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: EX19D033UWA004.ant.amazon.com (10.13.139.85) To EX19D001UWA003.ant.amazon.com (10.13.138.211) Relaxed poll until desired mask/value is observed at the specified address or timeout. This macro is a specialization of the generic smp_cond_load_relaxed(), which takes a simple mask/value condition (vcond) instead of an arbitrary expression. It allows architectures to better specialize the implementation, e.g. to enable wfe() polling of the address on arm. Signed-off-by: Haris Okanovic --- include/asm-generic/barrier.h | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/include/asm-generic/barrier.h b/include/asm-generic/barrier.h index d4f581c1e21d..112027eabbfc 100644 --- a/include/asm-generic/barrier.h +++ b/include/asm-generic/barrier.h @@ -256,6 +256,31 @@ do { \ }) #endif +/** + * smp_vcond_load_relaxed() - (Spin) wait until an expected value at address + * with no ordering guarantees. Spins until `(*addr & mask) == val` or + * `nsecs` elapse, and returns the last observed `*addr` value. + * + * @nsecs: timeout in nanoseconds + * @addr: pointer to an integer + * @mask: a bit mask applied to read values + * @val: Expected value with mask + */ +#ifndef smp_vcond_load_relaxed +#define smp_vcond_load_relaxed(nsecs, addr, mask, val) ({ \ + const u64 __start = local_clock_noinstr(); \ + u64 __nsecs = (nsecs); \ + typeof(addr) __addr = (addr); \ + typeof(*__addr) __mask = (mask); \ + typeof(*__addr) __val = (val); \ + typeof(*__addr) __cur; \ + smp_cond_load_relaxed(__addr, ( \ + (VAL & __mask) == __val || \ + local_clock_noinstr() - __start > __nsecs \ + )); \ +}) +#endif + /** * smp_cond_load_acquire() - (Spin) wait for cond with ACQUIRE ordering * @ptr: pointer to the variable to wait on