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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 2F0CDC83F2C for ; Sun, 3 Sep 2023 03:37:59 +0000 (UTC) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=bT4aIbls; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=bT4aIbls; dkim-atps=neutral Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Rdcsx4MBBz3c5S for ; Sun, 3 Sep 2023 13:37:57 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=bT4aIbls; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=bT4aIbls; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=redhat.com (client-ip=170.10.129.124; helo=us-smtp-delivery-124.mimecast.com; envelope-from=bhe@redhat.com; receiver=lists.ozlabs.org) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4Rdcrv3BmKz2xBF for ; Sun, 3 Sep 2023 13:37:01 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1693712218; 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=pKtB7jxT4Cb7Dh6mDUeRnvr1QZkonAikTMNrLOlN9ng=; b=bT4aIblsPocoiC0BNgfTqZpHACU5/bEkYdTaFnyemD7FGu1bcIZtz/jYX21SRXOybrTlFT +juGmuWT+2t+JmzEmMwziJy3DWGD3Hyg6QY1iXa+1wVpFEAAsxstsuHZB1geKmlbA+xRby yvM5h26/qWtGoPlDjYWn/B5NwFg0awk= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1693712218; 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=pKtB7jxT4Cb7Dh6mDUeRnvr1QZkonAikTMNrLOlN9ng=; b=bT4aIblsPocoiC0BNgfTqZpHACU5/bEkYdTaFnyemD7FGu1bcIZtz/jYX21SRXOybrTlFT +juGmuWT+2t+JmzEmMwziJy3DWGD3Hyg6QY1iXa+1wVpFEAAsxstsuHZB1geKmlbA+xRby yvM5h26/qWtGoPlDjYWn/B5NwFg0awk= 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-261-2R5AotwnOH2WWaOhBKVgZA-1; Sat, 02 Sep 2023 23:36:54 -0400 X-MC-Unique: 2R5AotwnOH2WWaOhBKVgZA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id E2BE610264C1; Sun, 3 Sep 2023 03:36:53 +0000 (UTC) Received: from localhost (unknown [10.72.112.18]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8F260D4781C; Sun, 3 Sep 2023 03:36:52 +0000 (UTC) Date: Sun, 3 Sep 2023 11:36:49 +0800 From: Baoquan He To: Hari Bathini Subject: Re: [PATCH 1/2] vmcore: allow alternate dump capturing methods to export vmcore without is_kdump_kernel() Message-ID: References: <20230901190438.375678-1-hbathini@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230901190438.375678-1-hbathini@linux.ibm.com> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev , Kexec-ml , lkml , Sourabh Jain , Mahesh J Salgaonkar , Dave Young Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Hi Hari, On 09/02/23 at 12:34am, Hari Bathini wrote: > 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. is_kdump_kernel() is used to restrict resources in crash > dump capture kernel but such restrictions may not be desirable for > fadump. Allow is_kdump_kernel() to be defined differently for such > scenarios. With this, is_kdump_kernel() could be false while vmcore > is usable. So, introduce is_crashdump_kernel() to return true when > elfcorehdr_addr is set and use it for vmcore related checks. I got what is done in these two patches, but didn't get why they need be done. vmcore_unusable()/is_vmcore_usable() are only unitilized in ia64. Why do you care if it's is_crashdump_kernel() or is_kdump_kernel()? If you want to override the generic is_kdump_kernel() with powerpc's own is_kdump_kernel(), your below change is enough to allow you to do that. I can't see why is_crashdump_kernel() is needed. Could you explain that specifically? #ifndef is_kdump_kernel static inline bool is_kdump_kernel(void) { return elfcorehdr_addr != ELFCORE_ADDR_MAX; } #endif Thanks Baoquan > [1] https://docs.kernel.org/powerpc/firmware-assisted-dump.html > > Signed-off-by: Hari Bathini > --- > include/linux/crash_dump.h | 18 ++++++++++++++++-- > 1 file changed, 16 insertions(+), 2 deletions(-) > > diff --git a/include/linux/crash_dump.h b/include/linux/crash_dump.h > index 0f3a656293b0..1052a0faf0dd 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 > + > +/* > + * Return true if this is a dump capture kernel, where vmcore needs to be > + * exported, irrespective of the dump capture mechanism in use. > + * > + * Same as is_kdump_kernel() unless arch specific code defines is_kdump_kernel() > + * differently while supporting other dump capturing mechanisms. > + */ > +static inline bool is_crashdump_kernel(void) > +{ > + return elfcorehdr_addr != ELFCORE_ADDR_MAX; > +} > > /* is_vmcore_usable() checks if the kernel is booting after a panic and > * the vmcore region is usable. > @@ -75,7 +89,7 @@ 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_crashdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0; > } > > /* vmcore_unusable() marks the vmcore as unusable, > @@ -84,7 +98,7 @@ static inline int is_vmcore_usable(void) > > static inline void vmcore_unusable(void) > { > - if (is_kdump_kernel()) > + if (is_crashdump_kernel()) > elfcorehdr_addr = ELFCORE_ADDR_ERR; > } > > -- > 2.41.0 >