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 66468C4332F for ; Thu, 14 Dec 2023 14:13:50 +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=4fbBL6IZD57NRtDznjuOr8wAnD/gOBWrNzcrgmHJvds=; b=mvsb37g45c8K5k SUSds32oIAStlGgt6QwsjEVOSdksUd5xFACRNdAPqMuWUu8OzXcRSj9z5qRgMdDHnXTAdurKlv718 q25u6nQkwOdmnc/48vI8kSrbGDihtOFn06X7ym4OF564grRBbdNgFd2RhotEFb35bb3V+rzsOIfPI Kxhln+yxVOfTM6caQBgpAr4ADowG4Oh+pw2xQiLG9aQ0tMy2ucGKrBWFXccNtcUcux83t7y53J+3l acl/20oQtAmgq0ntWICMMESfYc7/zSwiJWv7h4bv9rCa51iHBKxDc8y21mjUimoS3ZQW5hgfN6FON k9GXvzDMlIDLQMUga67Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rDmTE-000W3N-09; Thu, 14 Dec 2023 14:13:48 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1rDmTA-000W2i-2r for kexec@lists.infradead.org; Thu, 14 Dec 2023 14:13:46 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1702563223; 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=rWA4jrugxAphsdbeIh/acD095fJ5/82CDD3Wyi7fJAY=; b=CDcYV2A7amDf0HRgs1KmxF64jRHuhcuDsmvNLhPVdxTqPuMKJHyH/N4fTWXzXdUP8/OKWd TIcGYmgqGTXzLCJ3LAXTV6k2YnrK6Xmx4s1svtSCATGjvjaGijplugcuV9f8/kz34xvtvy UxlRJ6V+VXhgArqgxn6tUiiVSXpMzqM= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-610-sQoJWAN1MZCF3dhHJHsgwg-1; Thu, 14 Dec 2023 09:13:39 -0500 X-MC-Unique: sQoJWAN1MZCF3dhHJHsgwg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (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 mimecast-mx02.redhat.com (Postfix) with ESMTPS id 1D51E86EB22; Thu, 14 Dec 2023 14:13:37 +0000 (UTC) Received: from localhost (unknown [10.72.116.38]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A46303C25; Thu, 14 Dec 2023 14:13:35 +0000 (UTC) Date: Thu, 14 Dec 2023 22:13:33 +0800 From: Baoquan He To: Sourabh Jain Cc: linuxppc-dev@ozlabs.org, Akhil Raj , Andrew Morton , "Aneesh Kumar K . V" , Borislav Petkov , Boris Ostrovsky , Christophe Leroy , Dave Hansen , Dave Young , David Hildenbrand , Eric DeVolder , Greg Kroah-Hartman , Hari Bathini , Laurent Dufour , Mahesh Salgaonkar , Michael Ellerman , Mimi Zohar , Naveen N Rao , Oscar Salvador , Thomas Gleixner , Valentin Schneider , Vivek Goyal , kexec@lists.infradead.org, x86@kernel.org Subject: Re: [PATCH v14 2/6] crash: make CPU and Memory hotplug support reporting flexible Message-ID: References: <20231211083056.340404-1-sourabhjain@linux.ibm.com> <20231211083056.340404-3-sourabhjain@linux.ibm.com> MIME-Version: 1.0 In-Reply-To: <20231211083056.340404-3-sourabhjain@linux.ibm.com> X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231214_061344_994341_918F34ED X-CRM114-Status: GOOD ( 35.10 ) 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 12/11/23 at 02:00pm, Sourabh Jain wrote: > Architectures' specific functions `arch_crash_hotplug_cpu_support()` and > `arch_crash_hotplug_memory_support()` advertise the kernel's capability > to update the kdump image on CPU and Memory hotplug events to userspace > via the sysfs interface. These architecture-specific functions need to > access various attributes of the `kexec_crash_image` object to determine > whether the kernel can update the kdump image and advertise this > information to userspace accordingly. > > As the architecture-specific code is not exposed to the APIs required to > acquire the lock for accessing the `kexec_crash_image` object, it calls > a generic function, `crash_check_update_elfcorehdr()`, to determine > whether the kernel can update the kdump image or not. > > The lack of access to the `kexec_crash_image` object in > architecture-specific code restricts architectures from performing > additional architecture-specific checks required to determine if the > kdump image is updatable or not. For instance, on PowerPC, the kernel > can update the kdump image only if both the elfcorehdr and FDT are > marked as updatable for the `kexec_load` system call. > > So define two generic functions, `crash_hotplug_cpu_support()` and > `crash_hotplug_memory_support()`, which are called when userspace > attempts to read the crash CPU and Memory hotplug support via the sysfs > interface. These functions take the necessary locks needed to access the > `kexec_crash_image` object and then forward it to the > architecture-specific handler to do the rest. > > Signed-off-by: Sourabh Jain > Cc: Akhil Raj > Cc: Andrew Morton > Cc: Aneesh Kumar K.V > Cc: Baoquan He > Cc: Borislav Petkov (AMD) > Cc: Boris Ostrovsky > Cc: Christophe Leroy > Cc: Dave Hansen > Cc: Dave Young > Cc: David Hildenbrand > Cc: Eric DeVolder > Cc: Greg Kroah-Hartman > Cc: Hari Bathini > Cc: Laurent Dufour > Cc: Mahesh Salgaonkar > Cc: Michael Ellerman > Cc: Mimi Zohar > Cc: Naveen N Rao > Cc: Oscar Salvador > Cc: Thomas Gleixner > Cc: Valentin Schneider > Cc: Vivek Goyal > Cc: kexec@lists.infradead.org > Cc: x86@kernel.org > --- > arch/x86/include/asm/kexec.h | 8 ++++---- > arch/x86/kernel/crash.c | 20 +++++++++++++++----- > include/linux/kexec.h | 13 +++++++------ > kernel/crash_core.c | 23 +++++++++++++++++------ > 4 files changed, 43 insertions(+), 21 deletions(-) > > diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h > index 9bb6607e864e..5c88d27b086d 100644 > --- a/arch/x86/include/asm/kexec.h > +++ b/arch/x86/include/asm/kexec.h > @@ -212,13 +212,13 @@ void arch_crash_handle_hotplug_event(struct kimage *image, void *arg); > #define arch_crash_handle_hotplug_event arch_crash_handle_hotplug_event > > #ifdef CONFIG_HOTPLUG_CPU > -int arch_crash_hotplug_cpu_support(void); > -#define crash_hotplug_cpu_support arch_crash_hotplug_cpu_support > +int arch_crash_hotplug_cpu_support(struct kimage *image); > +#define arch_crash_hotplug_cpu_support arch_crash_hotplug_cpu_support > #endif > > #ifdef CONFIG_MEMORY_HOTPLUG > -int arch_crash_hotplug_memory_support(void); > -#define crash_hotplug_memory_support arch_crash_hotplug_memory_support > +int arch_crash_hotplug_memory_support(struct kimage *image); > +#define arch_crash_hotplug_memory_support arch_crash_hotplug_memory_support > #endif > > unsigned int arch_crash_get_elfcorehdr_size(void); > diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c > index 0d7b2657beb6..ad5941665589 100644 > --- a/arch/x86/kernel/crash.c > +++ b/arch/x86/kernel/crash.c > @@ -398,18 +398,28 @@ int crash_load_segments(struct kimage *image) > #undef pr_fmt > #define pr_fmt(fmt) "crash hp: " fmt > > -/* These functions provide the value for the sysfs crash_hotplug nodes */ > +#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_MEMORY_HOTPLUG) > +static int crash_hotplug_support(struct kimage *image) > +{ > + if (image->file_mode) > + return 1; > + > + return image->update_elfcorehdr; > +} > +#endif > + > #ifdef CONFIG_HOTPLUG_CPU > -int arch_crash_hotplug_cpu_support(void) > +/* These functions provide the value for the sysfs crash_hotplug nodes */ > +int arch_crash_hotplug_cpu_support(struct kimage *image) > { > - return crash_check_update_elfcorehdr(); > + return crash_hotplug_support(image); > } > #endif > > #ifdef CONFIG_MEMORY_HOTPLUG > -int arch_crash_hotplug_memory_support(void) > +int arch_crash_hotplug_memory_support(struct kimage *image) > { > - return crash_check_update_elfcorehdr(); > + return crash_hotplug_support(image); > } > #endif > > diff --git a/include/linux/kexec.h b/include/linux/kexec.h > index ee28c09a7fb0..0f6ea35879ee 100644 > --- a/include/linux/kexec.h > +++ b/include/linux/kexec.h > @@ -486,16 +486,17 @@ static inline void arch_kexec_pre_free_pages(void *vaddr, unsigned int pages) { > static inline void arch_crash_handle_hotplug_event(struct kimage *image, void *arg) { } > #endif > > -int crash_check_update_elfcorehdr(void); > - > -#ifndef crash_hotplug_cpu_support > -static inline int crash_hotplug_cpu_support(void) { return 0; } > +#ifndef arch_crash_hotplug_cpu_support > +static inline int arch_crash_hotplug_cpu_support(struct kimage *image) { return 0; } > #endif > > -#ifndef crash_hotplug_memory_support > -static inline int crash_hotplug_memory_support(void) { return 0; } > +#ifndef arch_crash_hotplug_memory_support > +static inline int arch_crash_hotplug_memory_support(struct kimage *image) { return 0; } > #endif > > +extern int crash_hotplug_cpu_support(void); > +extern int crash_hotplug_memory_support(void); > + > #ifndef crash_get_elfcorehdr_size > static inline unsigned int crash_get_elfcorehdr_size(void) { return 0; } > #endif > diff --git a/kernel/crash_core.c b/kernel/crash_core.c > index b9190265fe52..b621f03c1104 100644 > --- a/kernel/crash_core.c > +++ b/kernel/crash_core.c > @@ -892,12 +892,14 @@ DEFINE_MUTEX(__crash_hotplug_lock); > #define crash_hotplug_lock() mutex_lock(&__crash_hotplug_lock) > #define crash_hotplug_unlock() mutex_unlock(&__crash_hotplug_lock) > > +#define CPU_HOTPLUG 0 > +#define MEM_HOTPLUG 1 > /* > * This routine utilized when the crash_hotplug sysfs node is read. > * It reflects the kernel's ability/permission to update the crash > * elfcorehdr directly. > */ > -int crash_check_update_elfcorehdr(void) > +static int crash_hotplug_support(int hotplug) Is it possible that we rename this function to different name? e.g crash_hotplug_check_support() or other name. We may easily mixing it up with the one of ARCH version. personal opinion. > { > int rc = 0; > > @@ -909,18 +911,27 @@ int crash_check_update_elfcorehdr(void) > return 0; > } > if (kexec_crash_image) { > - if (kexec_crash_image->file_mode) > - rc = 1; > - else > - rc = kexec_crash_image->update_elfcorehdr; > + if (hotplug == CPU_HOTPLUG) > + rc = arch_crash_hotplug_cpu_support(kexec_crash_image); > + else if (hotplug == MEM_HOTPLUG) > + rc = arch_crash_hotplug_memory_support(kexec_crash_image); > } > /* Release lock now that update complete */ > kexec_unlock(); > crash_hotplug_unlock(); > - > return rc; > } > > +int crash_hotplug_cpu_support(void) > +{ > + return crash_hotplug_support(CPU_HOTPLUG); > +} > + > +int crash_hotplug_memory_support(void) > +{ > + return crash_hotplug_support(MEM_HOTPLUG); > +} > + > /* > * To accurately reflect hot un/plug changes of cpu and memory resources > * (including onling and offlining of those resources), the elfcorehdr > -- > 2.41.0 > _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec