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 B020BCA0FF3 for ; Tue, 5 Sep 2023 16:00:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232756AbjIEQAF (ORCPT ); Tue, 5 Sep 2023 12:00:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41976 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343497AbjIECbd (ORCPT ); Mon, 4 Sep 2023 22:31:33 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 721C0CC6 for ; Mon, 4 Sep 2023 19:30:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1693881040; 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=+TD6AqqZEhek/ZfRieu/bQVlET4Mzq9l0FIdUCSmPvI=; b=J+gRzbU3NUxr6GTr6N4FhpZFJeEo1H/c1C0sIhUS3j1baOf5I7wghkfoIiB+Mn1/yt+qjV g/CS+nb4kPxMlYz/+S9R/GdnDr/DwAUU7T+8q8KHg0rOWN6FdlnNYdOjmFwN5KpmXYyHVl 5VM+Jdu3OvJa5vUVsC+kPJKDUyy9j+c= 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-321-1_odNUnyN7S2l__P_hDscg-1; Mon, 04 Sep 2023 22:30:37 -0400 X-MC-Unique: 1_odNUnyN7S2l__P_hDscg-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id C626B8CB2D7; Tue, 5 Sep 2023 02:30:36 +0000 (UTC) Received: from localhost (unknown [10.72.113.126]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 171AD200BAA9; Tue, 5 Sep 2023 02:30:35 +0000 (UTC) Date: Tue, 5 Sep 2023 10:30:32 +0800 From: Baoquan He To: Hari Bathini Cc: linuxppc-dev , Kexec-ml , lkml , Sourabh Jain , Mahesh J Salgaonkar , Dave Young 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> <8fcd7ba7-0f27-7bbc-676f-7e13c8bf00d7@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8fcd7ba7-0f27-7bbc-676f-7e13c8bf00d7@linux.ibm.com> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/04/23 at 08:04pm, Hari Bathini wrote: > Hi Baoquan, > > Thanks for the review... > > On 03/09/23 9:06 am, Baoquan He wrote: > > 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? > > You mean to just remove is_kdump_kernel() check in is_vmcore_usable() & > vmcore_unusable() functions? Replaced generic is_crashdump_kernel() > function instead, that returns true for any dump capturing method, > irrespective of whether is_kdump_kernel() returns true or false. > For fadump case, is_kdump_kernel() will return false after patch 2/2. OK, I could understand what you want to achieve. You want to make is_kdump_kernel() only return true for kdump, while is_vmcore_usable() returns true for both kdump and fadump. IIUC, can we change as below? It could make code clearer and more straightforward. I don't think adding another is_crashdump_kernel() is a good idea, that would be a torture for non-powerpc people reading code when they need differentiate between kdump and crashdump. diff --git a/include/linux/crash_dump.h b/include/linux/crash_dump.h index 0f3a656293b0..102a8b710b38 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_active /* * 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 +65,14 @@ static inline bool is_kdump_kernel(void) { return elfcorehdr_addr != ELFCORE_ADDR_MAX; } +#endif + +#ifndef is_fadump_active +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 +84,8 @@ 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 +94,7 @@ 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; }