From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.linuxfoundation.org ([140.211.169.12]) by bombadil.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1S2AR7-0000aw-I9 for kexec@lists.infradead.org; Mon, 27 Feb 2012 23:56:59 +0000 Date: Mon, 27 Feb 2012 15:56:43 -0800 From: Andrew Morton Subject: Re: [PATCH] kexec: crash: don't save swapper_pg_dir for !CONFIG_MMU configurations Message-Id: <20120227155643.cafb1c6d.akpm@linux-foundation.org> In-Reply-To: <20120227235235.GE24159@verge.net.au> References: <1330094447-11900-1-git-send-email-will.deacon@arm.com> <20120225023748.GE21429@verge.net.au> <20120226225842.GA23028@mudshark.cambridge.arm.com> <20120227003727.GA30831@verge.net.au> <20120227193054.GB24605@mudshark.cambridge.arm.com> <20120227235235.GE24159@verge.net.au> Mime-Version: 1.0 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-bounces@lists.infradead.org Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Simon Horman Cc: "kexec@lists.infradead.org" , Will Deacon On Tue, 28 Feb 2012 08:52:35 +0900 Simon Horman wrote: > On Mon, Feb 27, 2012 at 07:30:54PM +0000, Will Deacon wrote: > > On Mon, Feb 27, 2012 at 12:37:30AM +0000, Simon Horman wrote: > > > On Sun, Feb 26, 2012 at 10:58:42PM +0000, Will Deacon wrote: > > > > On Sat, Feb 25, 2012 at 02:37:49AM +0000, Simon Horman wrote: > > > > > > > > > might this cover cases where swapper_pg_dir is interesting? > > > > > > > > The only case where it's interesting is when you have CONFIG_MMU enabled - > > > > otherwise it's always NULL. If it's #defined as NULL, the current code will > > > > fail at build time so simply omitting it from the dump seems like the best > > > > bet to me (the alternative being to add a NULL entry explicitly, but I don't > > > > see what the gains us). > > > > > > Hi Will, > > > > > > thanks for the clarification. FWIW I am happy with your patch. > > > > > > Reviewed-by: Simon Horman > > > > Cheers, Simon. What's the usual path for generic kexec code getting into > > mainline? Do I need to get this queued somewhere? > > I think that Andrew Morton often picks up these kind of patches. I'll take anything, if I have any chance of vaguely understanding it ;) > Andrew, can you pick this up if its reposted with you CCed? > For reference the patch is as follows: > > > From: Will Deacon > > kexec: crash: don't save swapper_pg_dir for !CONFIG_MMU configurations > > nommu platforms don't have very interesting swapper_pg_dir pointers and > usually just #define them to NULL, meaning that we can't include them in > the vmcoreinfo on the kexec crash path. > > This patch only saves the swapper_pg_dir if we have an MMU. > > Signed-off-by: Will Deacon > Reviewed-by: Simon Horman > > --- > kernel/kexec.c | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > diff --git a/kernel/kexec.c b/kernel/kexec.c > index 7b08867..cb5d13c 100644 > --- a/kernel/kexec.c > +++ b/kernel/kexec.c > @@ -1462,7 +1462,9 @@ static int __init crash_save_vmcoreinfo_init(void) > > VMCOREINFO_SYMBOL(init_uts_ns); > VMCOREINFO_SYMBOL(node_online_map); > +#ifdef CONFIG_MMU > VMCOREINFO_SYMBOL(swapper_pg_dir); > +#endif > VMCOREINFO_SYMBOL(_stext); > VMCOREINFO_SYMBOL(vmlist); Well, what might be the effects of this patch? nommu crashfiles will no longer have the swapper_pg_dir string? What are the chances that someone's (badly written!) downstream tool will crash and burn if this is absent? _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec