From patchwork Fri Sep 6 10:59:03 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Sewior X-Patchwork-Id: 13794065 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1F34BCE7B02 for ; Fri, 6 Sep 2024 11:31:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:Message-ID:Date:Subject:Cc:To:From:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=HEP2lp2UMK+97IqGCmgYal4fO7wnNYZc3qCTmzndaog=; b=j7anmt4yB4+lNHCC4d1e8VJzPY OqreWoCKvl8iOJDouOzohxC5aQcYD7hl9SEDRx5G5pXkHd8zJXWZf9Bj0E7zj3gClbU/s5a1ju7WP que5umoIrC1VnHzRTR6zqqxDo7HO7hvNU3r/cqM56k/69xKS12GMSgNTbGlmLd/I7d5WlGllH3+oS T76DYgp63yVW7VDd3MuBTYjgfAhtdXUWApBjg93EbqPTkM2ufTH+RmVmYOT9VC06nWkJfOlSY6rw+ +v/lUlI1bWkKxIPQeLvIc/M4b0Dvr6ZNyDIckDOzWMW6cjMp+mqkydm67BIVvcJC7o7dVBpu34Qpf F9M4ieKw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1smXBX-0000000Bzb3-0s6x; Fri, 06 Sep 2024 11:31:27 +0000 Received: from galois.linutronix.de ([2a0a:51c0:0:12e:550::1]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1smWzM-0000000BwHh-0bbd; Fri, 06 Sep 2024 11:19:02 +0000 From: Sebastian Andrzej Siewior DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1725621527; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=HEP2lp2UMK+97IqGCmgYal4fO7wnNYZc3qCTmzndaog=; b=cPERfHJ4Tj2syRS4X5vjMKijkIyRTwEw9huXhX9ScPLCS0xD+UUfqUaFqNU7HN81DP+lms FCbf+Om+VF0i75oYNFOg/X2Mk0PkXhJeNbIshIc7TdWBM29Heg/58FfdaaVNnKbUql8sIF 5E8xkD3wqFvc2OGbJCzCQFEZVUNjlfs7Qq08SQ3RvXsjRsRh29ajYXz00ETMQcW/L6HZ1p 715/QF7D7Qy9nUF6DcbeU1cXpBBgeSo3O9OcZy/BhYtfZJfhiKWSb7qrJjIR3wtEX+f7/F ZYRMv5y+Ai8LOB8AtcG8/sN5Zipm+pA2TIhhhh1Yw/tm4x+VsxopQtkGSCV26Q== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1725621527; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=HEP2lp2UMK+97IqGCmgYal4fO7wnNYZc3qCTmzndaog=; b=1Zo+jdnBuun2+Zt18Bs7uRsHBtWFLpAlPrv1lIh0pP2m77SRND7ZqSK2NhuFslp4lFSirE 8K5jxNV6h5G6rnAw== To: Thomas Gleixner , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, x86@kernel.org Cc: "H. Peter Anvin" , Albert Ou , Borislav Petkov , Catalin Marinas , Clark Williams , Dave Hansen , Ingo Molnar , John Ogness , Palmer Dabbelt , Paul Walmsley , Petr Mladek , Sergey Senozhatsky , Steven Rostedt , Will Deacon Subject: [PATCH 0/3] Allow to enable PREEMPT_RT. Date: Fri, 6 Sep 2024 12:59:03 +0200 Message-ID: <20240906111841.562402-1-bigeasy@linutronix.de> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240906_041852_375232_AC40D129 X-CRM114-Status: UNSURE ( 4.93 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org The printk bits required for PREEMPT_RT are sitting in linux-next. This was the last known roadblock for PREEMPT_RT. The RT queue has additionally the "atomic console" for the 8250 UART which is not yet in linux-next. This means "legacy console" behaviour as in no printing from atomic context in emergency cases. The 8250 UART driver is the only one providing "atomic console" support as of today. With the printk bits merged, PREEMPT_RT could be enabled on X86, ARM64 and Risc-V. These three architectures merged required changes over the years leaving me in a position where I have no essential changes in the queue that would affect them. ARM and POWERPC have a few essential patches left and I lost track of MIPS. Sebastian