From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753270AbeDSATb (ORCPT ); Wed, 18 Apr 2018 20:19:31 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:45384 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753065AbeDSAT2 (ORCPT ); Wed, 18 Apr 2018 20:19:28 -0400 From: Baoquan He To: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, robh+dt@kernel.org, dan.j.williams@intel.com, nicolas.pitre@linaro.org, josh@joshtriplett.org Cc: Baoquan He , Eric Biederman , Vivek Goyal , Dave Young , Yinghai Lu , kexec@lists.infradead.org Subject: [PATCH v3 3/3] kexec_file: Load kernel at top of system RAM if required Date: Thu, 19 Apr 2018 08:18:48 +0800 Message-Id: <20180419001848.3041-4-bhe@redhat.com> In-Reply-To: <20180419001848.3041-1-bhe@redhat.com> References: <20180419001848.3041-1-bhe@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org For kexec_file loading, if kexec_buf.top_down is 'true', the memory which is used to load kernel/initrd/purgatory is supposed to be allocated from top to down. This is what we have been doing all along in the old kexec loading interface and the kexec loading is still default setting in some distributions. However, the current kexec_file loading interface doesn't do likt this. The function arch_kexec_walk_mem() it calls ignores checking kexec_buf.top_down, but calls walk_system_ram_res() directly to go through all resources of System RAM from bottom to up, to try to find memory region which can contain the specific kexec buffer, then call locate_mem_hole_callback() to allocate memory in that found memory region from top to down. This brings confusion. These two interfaces need be unified on behaviour. Here add checking if kexec_buf.top_down is 'true' in arch_kexec_walk_mem(), if yes, call the newly added walk_system_ram_res_rev() to find memory region from top to down to load kernel. Signed-off-by: Baoquan He Cc: Eric Biederman Cc: Vivek Goyal Cc: Dave Young Cc: Andrew Morton Cc: Yinghai Lu Cc: kexec@lists.infradead.org --- kernel/kexec_file.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index 75d8e7cf040e..7a66d9d5a534 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -518,6 +518,8 @@ int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf, IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY, crashk_res.start, crashk_res.end, kbuf, func); + else if (kbuf->top_down) + return walk_system_ram_res_rev(0, ULONG_MAX, kbuf, func); else return walk_system_ram_res(0, ULONG_MAX, kbuf, func); } -- 2.13.6