From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751409Ab2GBLuO (ORCPT ); Mon, 2 Jul 2012 07:50:14 -0400 Received: from e28smtp02.in.ibm.com ([122.248.162.2]:60930 "EHLO e28smtp02.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750886Ab2GBLuL (ORCPT ); Mon, 2 Jul 2012 07:50:11 -0400 From: "Suzuki K. Poulose" Subject: [PATCH] [powerpc] Export memory limit via device tree To: benh@kernel.crashing.org Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, mahesh@linux.vnet.ibm.com, hbabu@us.ibm.com Date: Mon, 02 Jul 2012 17:19:00 +0530 Message-ID: <20120702114855.22333.95335.stgit@suzukikp.in.ibm.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit x-cbid: 12070211-5816-0000-0000-00000367927C Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The powerpc kernel doesn't export the memory limit enforced by 'mem=' kernel parameter. This is required for building the ELF header in kexec-tools to limit the vmcore to capture only the used memory. On powerpc the kexec-tools depends on the device-tree for memory related information, unlike /proc/iomem on the x86. Without this information, the kexec-tools assumes the entire System RAM and vmcore creates an unnecessarily larger dump. This patch exports the memory limit, if present, via chosen/linux,memory-limit property, so that the vmcore can be limited to the memory limit. The prom_init seems to export this value in the same node. But doesn't really appear there. Also the memory_limit gets adjusted with the processing of crashkernel= parameter. This patch makes sure we get the actual limit. The kexec-tools will use the value to limit the 'end' of the memory regions. Tested this patch on ppc64 and ppc32(ppc440) with a kexec-tools patch by Mahesh. Signed-off-by: Suzuki K. Poulose Tested-by: Mahesh J. Salgaonkar --- arch/powerpc/kernel/machine_kexec.c | 15 +++++++++++++++ 1 files changed, 15 insertions(+), 0 deletions(-) diff --git a/arch/powerpc/kernel/machine_kexec.c b/arch/powerpc/kernel/machine_kexec.c index c957b12..0c9695d 100644 --- a/arch/powerpc/kernel/machine_kexec.c +++ b/arch/powerpc/kernel/machine_kexec.c @@ -207,6 +207,12 @@ static struct property crashk_size_prop = { .value = &crashk_size, }; +static struct property memory_limit_prop = { + .name = "linux,memory-limit", + .length = sizeof(phys_addr_t), + .value = &memory_limit, +}; + static void __init export_crashk_values(struct device_node *node) { struct property *prop; @@ -226,6 +232,15 @@ static void __init export_crashk_values(struct device_node *node) crashk_size = resource_size(&crashk_res); prom_add_property(node, &crashk_size_prop); } + + /* memory-limit is needed for constructing the crash regions */ + prop = of_find_property(node, memory_limit_prop.name, NULL); + if (prop) + prom_remove_property(node, prop); + + if (memory_limit) + prom_add_property(node, &memory_limit_prop); + } static int __init kexec_setup(void)