From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 AE0961741D1 for ; Mon, 30 Sep 2024 10:22:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727691748; cv=none; b=TlDCwOMAiZy2bsUAU3iys+6w2ic+dP642Ysuq3VDQOw15lAholeQASsb5+ePsYCGz3QXptadkMF0aFZrvfRiJdfkUHF1EAmz6nqsyxcxz90jdJIbIPjJCyI+a0qZnF8W5Su0yBy+1WwYlT/3PjsYtOcCtWj/ZsEfIxoFFr1uFbE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727691748; c=relaxed/simple; bh=XnAIQZY3d0mjEO/MmhFTWYhC82TcLroMyoi4wIznrCY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=VeupV43gSYMbVdCm24uJ5hZqTVURUJAVZ/3yryRr2ZZVVkDTtwwgGFSefwaNV3vyPlp9ybAPRZ/d+JXE60ZhlMUczBib7659zImapJmV0izr3bdJzVGxR4kOAh34yZC+0hPvE9JB6Hd5bFy/pp0UrY9j0oMZj0AK7IsUWM/QSiA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=ZFHQNYwa; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=vQjC5srC; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="ZFHQNYwa"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="vQjC5srC" Date: Mon, 30 Sep 2024 12:22:23 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1727691744; 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: in-reply-to:in-reply-to:references:references; bh=4eSp9RkDK47YInIXsiINyou7i4My3KIjpO1cjCWuO4w=; b=ZFHQNYwafO0wZuT/ucBNEf7mejaRtFogfwHX+VWL8/tLERbkug7vhX83r300VXMauBYIe3 FWRXoCrc9Q63CEKxNEA2/tKreJ6gdOr24jP+WPbhCVXepbFx2rUBCoxnklDQPoIqvXLKZn fQzr8CaBffzGpxy6gbQtOeOEAytYGlkz9Sux/euMmhwC9lyoQiwER82fBu/hUq2O34Tr6t 8+N9uVgQq2DZeTsOfl7CgAPHTPnhIe0pwZAZddPpQr8q767iOJkCEkTYORlACc37mWcP5Y DcsqhvHpLHelkefNg096G02+wJscoQBZNHGEx6eXFQWujHSA9zCvmSWpIZmcGg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1727691744; 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: in-reply-to:in-reply-to:references:references; bh=4eSp9RkDK47YInIXsiINyou7i4My3KIjpO1cjCWuO4w=; b=vQjC5srCXfVvsUCLZIq61F2rL45WSJ7g88iAMm1caVtgkFpDO35RA8xrVfAy1NUtMEQEmk KvAcf/r37Vm0ljCQ== From: Sebastian Andrzej Siewior To: Shrikanth Hegde Cc: linux-kernel@vger.kernel.org, Ingo Molnar , John Ogness , Steven Rostedt , Thomas Gleixner , Peter Zijlstra , Michael Ellerman Subject: Re: [PATCH 0/3] Allow to enable PREEMPT_RT. Message-ID: <20240930102223.j780j0oy@linutronix.de> References: <20240906111841.562402-1-bigeasy@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable In-Reply-To: On 2024-09-30 10:39:17 [+0530], Shrikanth Hegde wrote: > Hi Sebastian. Hi Shrikanth, >=20 > Added the ARCH_SUPPORTS_RT in arch/powerpc/Kconfig. Selected the preempt_= rt in menuconfig. > It *compiled and booted successfully* on POWERPC/ppc64le. =E2=80=A6 > So, Curious to know what are those patches that are left for POWERPC? > would like to work on those and get it enabled on POWERPC. Based on [0] this is what I have in my queue: | powerpc__traps__Use_PREEMPT_RT.patch | powerpc_pseries_iommu__Use_a_locallock_instead_local_irq_save.patch | powerpc-pseries-Select-the-generic-memory-allocator.patch | powerpc_kvm__Disable_in-kernel_MPIC_emulation_for_PREEMPT_RT.patch | powerpc_stackprotector__work_around_stack-guard_init_from_atomic.patch | POWERPC__Allow_to_enable_RT.patch Be aware that PREEMPT_RT run only on 32bit PowerPC and 64bit from FSL which is the embedded variant. That means it (64bit) had altivec but also a "simple" MMU. The P-Series (server grade hardware) version has a hashing MMU which has additional locking constrains. I never tested this outside of qemu and this was limited to booting. The traps patch in the queue was submitted a while ago https://lore.kernel.org/linuxppc-dev/20191015191821.11479-4-bigeasy@linutr= onix.de/ and reduced to the traps.c part. The powerpc should be reviewed and then decided what to do with them before enabling. [0] https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git/t= ree/patches/series?h=3Dv6.11-rt7-patches&id=3D28e79a9ab2504e245837070f27f52= 5520a6f5acb#n147 Sebastian