From mboxrd@z Thu Jan 1 00:00:00 1970 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 6F4AEC6FD19 for ; Thu, 16 Mar 2023 10:11:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=5EFctHSZ1cBl4ABZhhxkiNC5q/vlh0DKfknc6G+1rJI=; b=VgQDZ8rR5WVob+ OXX4bSVPAnUs5KburpHvYRkX4j1efc+s1fxCBxVnckao0Ze1n3bFI2P4sdYit75CO7vVsh2BXLHoC PEdNpSaXhskyv+FcDa8b94Is8NJxbmkFMan5t1g1o8UVMSTtERbf20l2R3w3tI+p9+id/W5g6DM5p 8bma7Dr5av0JkXV8jLOvE8m0D4SvTwumagWbcVo9iIL8NYuQCZEgxyIrSyzIZNH54ot9G5xUWRHXL wCUXtNnHs8dHLzOqnx3AWZP720uZ9nkiLm4kxrCyQqsMkYmJlqYRlPFsnZoEW+IwCd5CZh8uDB3Gz cpWmOvyeGgA2FnBbUP4g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pckaD-00FzHp-2C; Thu, 16 Mar 2023 10:11:41 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1pckaA-00FzGr-2e for kexec@lists.infradead.org; Thu, 16 Mar 2023 10:11:40 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1678961497; 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: in-reply-to:in-reply-to:references:references; bh=85fsDNz+lL7FHNJ1iBNzrAf34oVvetUItgQ6w01KkXg=; b=CFuZBAiqcmFiQPbH10yxQEHkhAt0jkDW0vRJP6sF1MPfJOTV49iB6XJ0kVFhXSEO2mm3XZ 2eOAec3ljGUY7fsCALOVqXhekXfNgsn/p0AQ6Ei7t7OwurE/4zTg1Yu8qJBzLnpsX5DrIg qbh8kdteHMTSWOzcEeERIuaMmqdn5LI= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-225-6DMdYaQDM0Kz1urE3t7CmQ-1; Thu, 16 Mar 2023 06:11:33 -0400 X-MC-Unique: 6DMdYaQDM0Kz1urE3t7CmQ-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 8FE3B800B23; Thu, 16 Mar 2023 10:11:31 +0000 (UTC) Received: from localhost (ovpn-12-81.pek2.redhat.com [10.72.12.81]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E59B32A68; Thu, 16 Mar 2023 10:11:29 +0000 (UTC) Date: Thu, 16 Mar 2023 18:11:26 +0800 From: Baoquan He To: Eric DeVolder Cc: linux-kernel@vger.kernel.org, x86@kernel.org, kexec@lists.infradead.org, ebiederm@xmission.com, dyoung@redhat.com, vgoyal@redhat.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, nramas@linux.microsoft.com, thomas.lendacky@amd.com, robh@kernel.org, efault@gmx.de, rppt@kernel.org, david@redhat.com, sourabhjain@linux.ibm.com, konrad.wilk@oracle.com, boris.ostrovsky@oracle.com Subject: Re: [PATCH v19 2/7] crash: add generic infrastructure for crash hotplug support Message-ID: References: <20230306162228.8277-1-eric.devolder@oracle.com> <20230306162228.8277-3-eric.devolder@oracle.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20230306162228.8277-3-eric.devolder@oracle.com> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230316_031138_955969_B88652D6 X-CRM114-Status: GOOD ( 20.45 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org On 03/06/23 at 11:22am, Eric DeVolder wrote: ...... > +static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu) > +{ > + /* Obtain lock while changing crash information */ > + if (kexec_trylock()) { > + > + /* Check kdump is loaded */ > + if (kexec_crash_image) { > + struct kimage *image = kexec_crash_image; > + > + if (hp_action == KEXEC_CRASH_HP_ADD_CPU || > + hp_action == KEXEC_CRASH_HP_REMOVE_CPU) > + pr_debug("hp_action %u, cpu %u\n", hp_action, cpu); > + else > + pr_debug("hp_action %u\n", hp_action); > + > + /* > + * When the struct kimage is allocated, the elfcorehdr_index > + * is set to -1. Find the segment containing the elfcorehdr, > + * if not already found. This works for both the kexec_load > + * and kexec_file_load paths. > + */ > + if (image->elfcorehdr_index < 0) { > + unsigned long mem; > + unsigned char *ptr; > + unsigned int n; > + > + for (n = 0; n < image->nr_segments; n++) { > + mem = image->segment[n].mem; > + ptr = kmap_local_page(pfn_to_page(mem >> PAGE_SHIFT)); > + if (ptr) { > + /* The segment containing elfcorehdr */ > + if (memcmp(ptr, ELFMAG, SELFMAG) == 0) { > + image->elfcorehdr_index = (int)n; > + } > + kunmap_local(ptr); > + } > + } > + } > + > + if (image->elfcorehdr_index < 0) { > + pr_err("unable to locate elfcorehdr segment"); > + goto out; > + } > + > + /* Needed in order for the segments to be updated */ > + arch_kexec_unprotect_crashkres(); > + > + /* Differentiate between normal load and hotplug update */ > + image->hp_action = hp_action; > + > + /* Now invoke arch-specific update handler */ > + arch_crash_handle_hotplug_event(image); > + > + /* No longer handling a hotplug event */ > + image->hp_action = KEXEC_CRASH_HP_NONE; > + image->elfcorehdr_updated = true; It's good to initialize the image->hp_action here, however where do you check it? Do you plan to add some check somewhere? > + > + /* Change back to read-only */ > + arch_kexec_protect_crashkres(); > + } > + > +out: > + /* Release lock now that update complete */ > + kexec_unlock(); > + } > +} ...... _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec