From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id DD2661A02D1 for ; Sat, 17 Oct 2015 13:04:05 +1100 (AEDT) Message-ID: <1445047433.24309.40.camel@kernel.crashing.org> Subject: Re: [PATCH] powerpc: on crash, kexec'ed kernel needs all CPUs are online From: Benjamin Herrenschmidt To: Laurent Vivier , David Gibson Cc: Paul Mackerras , Michael Ellerman , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, thuth@redhat.com Date: Sat, 17 Oct 2015 07:33:53 +0530 In-Reply-To: <5620ADE4.9060701@redhat.com> References: <1444935658-27319-1-git-send-email-lvivier@redhat.com> <20151016132943.1386fda6@voom.fritz.box> <5620ADE4.9060701@redhat.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, 2015-10-16 at 09:57 +0200, Laurent Vivier wrote: > For me the problem is: as these CPUs are offline, I guess the core has > been switched to 1 thread per core, so the CPUs (1 to 7 for core 0) > don't exist anymore, how can we return them to OPAL ? Another option is to make the new kernel kick_cpu fallback, if it knows it's coming as a crashdump, to sending IPIs. We would need some sane way to catch the guys coming it at 0x100 and route the to secondary start. Cheers, Ben.