Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751748AbdLETkY (ORCPT ); Tue, 5 Dec 2017 14:40:24 -0500 Received: from mail-vk0-f66.google.com ([209.85.213.66]:42217 "EHLO mail-vk0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750812AbdLETkW (ORCPT ); Tue, 5 Dec 2017 14:40:22 -0500 X-Google-Smtp-Source: AGs4zMa87XUmBVR58Xt6rrKPATuoCHepHGNt80DORcIPcVm1ygaJ3bUjzsJypy+A72jAhUViEtzXpw7jOzZOK/1esZs= MIME-Version: 1.0 In-Reply-To: <20171205085200.9528-3-fanc.fnst@cn.fujitsu.com> References: <20171205085200.9528-1-fanc.fnst@cn.fujitsu.com> <20171205085200.9528-3-fanc.fnst@cn.fujitsu.com> From: Kees Cook Date: Tue, 5 Dec 2017 11:40:20 -0800 X-Google-Sender-Auth: hEgfyQGk_cl2bYjbPpnQ20MAKWM Message-ID: Subject: Re: [PATCH v3 2/4] kaslr: calculate the memory region in immovable node To: Chao Fan Cc: LKML , X86 ML , "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , Baoquan He , yasu.isimatu@gmail.com, indou.takao@jp.fujitsu.com, caoj.fnst@cn.fujitsu.com, Dou Liyang Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4422 Lines: 118 On Tue, Dec 5, 2017 at 12:51 AM, Chao Fan wrote: > If there is no immovable memory region specified, go on the old code. > There are several conditons: > 1. CONFIG_MEMORY_HOTPLUG is not specified to y. > 2. immovable_mem= is not specified. > > Otherwise, calculate the intersecting between memmap entry and > immovable memory. Instead of copy/pasting code between process_efi_entries() and process_e820_entries(), I'd rather that process_mem_region() is modified to deal with immovable regions. -Kees > > Signed-off-by: Chao Fan > --- > arch/x86/boot/compressed/kaslr.c | 59 ++++++++++++++++++++++++++++++++++------ > 1 file changed, 51 insertions(+), 8 deletions(-) > > diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c > index 0bbbaf5f6370..e3a3b6132da0 100644 > --- a/arch/x86/boot/compressed/kaslr.c > +++ b/arch/x86/boot/compressed/kaslr.c > @@ -635,6 +635,39 @@ static void process_mem_region(struct mem_vector *entry, > } > } > > +static bool process_immovable_mem(struct mem_vector region, > + unsigned long long minimum, > + unsigned long long image_size) > +{ > + int i; > + > + /* > + * Walk all immovable regions, and filter the intersection > + * to process_mem_region. > + */ > + for (i = 0; i < num_immovable_region; i++) { > + struct mem_vector entry; > + unsigned long long start, end, entry_end; > + > + start = immovable_mem[i].start; > + end = start + immovable_mem[i].size; > + > + entry.start = clamp(region.start, start, end); > + entry_end = clamp(region.start + region.size, start, end); > + > + if (entry.start < entry_end) { > + entry.size = entry_end - entry.start; > + process_mem_region(&entry, minimum, image_size); > + } > + > + if (slot_area_index == MAX_SLOT_AREA) { > + debug_putstr("Aborted memmap scan (slot_areas full)!\n"); > + return 1; > + } > + } > + return 0; > +} > + > #ifdef CONFIG_EFI > /* > * Returns true if mirror region found (and must have been processed > @@ -700,11 +733,16 @@ process_efi_entries(unsigned long minimum, unsigned long image_size) > > region.start = md->phys_addr; > region.size = md->num_pages << EFI_PAGE_SHIFT; > - process_mem_region(®ion, minimum, image_size); > - if (slot_area_index == MAX_SLOT_AREA) { > - debug_putstr("Aborted EFI scan (slot_areas full)!\n"); > + > + /* If no immovable_mem stored, use region directly */ > + if (num_immovable_region == 0) { > + process_mem_region(®ion, minimum, image_size); > + if (slot_area_index == MAX_SLOT_AREA) { > + debug_putstr("Aborted memmap scan (slot_areas full)!\n"); > + break; > + } > + } else if (process_immovable_mem(region, minimum, image_size)) > break; > - } > } > return true; > } > @@ -731,11 +769,16 @@ static void process_e820_entries(unsigned long minimum, > continue; > region.start = entry->addr; > region.size = entry->size; > - process_mem_region(®ion, minimum, image_size); > - if (slot_area_index == MAX_SLOT_AREA) { > - debug_putstr("Aborted e820 scan (slot_areas full)!\n"); > + > + /* If no immovable_mem stored, use region directly */ > + if (num_immovable_region == 0) { > + process_mem_region(®ion, minimum, image_size); > + if (slot_area_index == MAX_SLOT_AREA) { > + debug_putstr("Aborted memmap scan (slot_areas full)!\n"); > + break; > + } > + } else if (process_immovable_mem(region, minimum, image_size)) > break; > - } > } > } > > -- > 2.14.3 > > > -- Kees Cook Pixel Security