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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 02D4DCA0EEC for ; Mon, 11 Sep 2023 22:22:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1359616AbjIKWSI (ORCPT ); Mon, 11 Sep 2023 18:18:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58324 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236386AbjIKKch (ORCPT ); Mon, 11 Sep 2023 06:32:37 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 1A6F3120 for ; Mon, 11 Sep 2023 03:31:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1694428306; 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=scL+PN7rvFW0rRtuvyrop8LP1MAlxFU5fgMf6KSanRA=; b=BYgJ8S/7aluC2EL4MIos0W/eh+Tdcm+5FgV2saBF1+/y1Uh+t4+mliikjaRdoPky2Xmoo1 RL+5AA0Rp6U583CXYqtZsm1hCbvqeHWwPXw9rHOO5i+lJBlKru2bRyVXX3U0TaOLtOmsKx QMIBijMKBhv9d21YbrLm7rKh/Wvnc0E= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-630-bOa0vEtiPUa0zpz8zjb7vQ-1; Mon, 11 Sep 2023 06:31:44 -0400 X-MC-Unique: bOa0vEtiPUa0zpz8zjb7vQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 662A5382254A; Mon, 11 Sep 2023 10:31:44 +0000 (UTC) Received: from localhost (unknown [10.72.112.35]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4FB1F40C200A; Mon, 11 Sep 2023 10:31:42 +0000 (UTC) Date: Mon, 11 Sep 2023 18:31:39 +0800 From: Baoquan He To: Michael Ellerman Cc: Hari Bathini , lkml , linuxppc-dev , Kexec-ml , Dave Young , Mahesh J Salgaonkar , Sourabh Jain Subject: Re: [PATCH v2 2/3] vmcore: allow fadump to export vmcore even if is_kdump_kernel() is false Message-ID: References: <20230905183604.568996-1-hbathini@linux.ibm.com> <20230905183604.568996-2-hbathini@linux.ibm.com> <8734zltc6z.fsf@mail.lhotse> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8734zltc6z.fsf@mail.lhotse> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/11/23 at 05:13pm, Michael Ellerman wrote: > Hari Bathini writes: > > Currently, is_kdump_kernel() returns true when elfcorehdr_addr is set. > > While elfcorehdr_addr is set for kexec based kernel dump mechanism, > > alternate dump capturing methods like fadump [1] also set it to export > > the vmcore. Since, is_kdump_kernel() is used to restrict resources in > > crash dump capture kernel and such restrictions are not desirable for > > fadump, allow is_kdump_kernel() to be defined differently for fadump > > case. With that change, include is_fadump_active() check in functions > > is_vmcore_usable() & vmcore_unusable() to be able to export vmcore for > > fadump case too. > ... > > diff --git a/include/linux/crash_dump.h b/include/linux/crash_dump.h > > index 0f3a656293b0..de8a9fabfb6f 100644 > > --- a/include/linux/crash_dump.h > > +++ b/include/linux/crash_dump.h > > @@ -50,6 +50,7 @@ void vmcore_cleanup(void); > > #define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x)) > > #endif > > > > +#ifndef is_kdump_kernel > > /* > > * is_kdump_kernel() checks whether this kernel is booting after a panic of > > * previous kernel or not. This is determined by checking if previous kernel > > @@ -64,6 +65,19 @@ static inline bool is_kdump_kernel(void) > > { > > return elfcorehdr_addr != ELFCORE_ADDR_MAX; > > } > > +#endif > > + > > +#ifndef is_fadump_active > > +/* > > + * If f/w assisted dump capturing mechanism (fadump), instead of kexec based > > + * dump capturing mechanism (kdump) is exporting the vmcore, then this function > > + * will be defined in arch specific code to return true, when appropriate. > > + */ > > +static inline bool is_fadump_active(void) > > +{ > > + return false; > > +} > > +#endif > > > > /* is_vmcore_usable() checks if the kernel is booting after a panic and > > * the vmcore region is usable. > > @@ -75,7 +89,8 @@ static inline bool is_kdump_kernel(void) > > > > static inline int is_vmcore_usable(void) > > { > > - return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0; > > + return (is_kdump_kernel() || is_fadump_active()) > > + && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0; > > } > > > > /* vmcore_unusable() marks the vmcore as unusable, > > @@ -84,7 +99,7 @@ static inline int is_vmcore_usable(void) > > > > static inline void vmcore_unusable(void) > > { > > - if (is_kdump_kernel()) > > + if (is_kdump_kernel() || is_fadump_active()) > > elfcorehdr_addr = ELFCORE_ADDR_ERR; > > } > > I think it would be cleaner to decouple is_vmcore_usable() and > vmcore_usable() from is_kdump_kernel(). > > ie, make them operate solely based on the value of elforehdr_addr: > > static inline int is_vmcore_usable(void) > { > elfcorehdr_addr != ELFCORE_ADDR_ERR && \ > elfcorehdr_addr != ELFCORE_ADDR_MAX; Agree. I fell into the blind corner of thinking earlier. Above change is better. > } > > static inline void vmcore_unusable(void) > { > elfcorehdr_addr = ELFCORE_ADDR_ERR; > } > > > Then all we need on powerpc is a way to override is_kdump_kernel(). > > cheers >