From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755826AbdELE1U (ORCPT ); Fri, 12 May 2017 00:27:20 -0400 Received: from mgwkm03.jp.fujitsu.com ([202.219.69.170]:48497 "EHLO mgwkm03.jp.fujitsu.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752376AbdELE1T (ORCPT ); Fri, 12 May 2017 00:27:19 -0400 X-Greylist: delayed 681 seconds by postgrey-1.27 at vger.kernel.org; Fri, 12 May 2017 00:27:18 EDT X-SecurityPolicyCheck: OK by SHieldMailChecker v2.5.2 X-SHieldMailCheckerPolicyVersion: FJ-ISEC-20161115-1 X-SHieldMailCheckerMailID: 425f45c359a54eda8df9c1b7ae072f28 Date: Fri, 12 May 2017 13:15:16 +0900 From: Masayoshi Mizuma To: Baoquan He Subject: Re: [PATCH v4 2/3] KASLR: Handle memory limit specified by memmap and mem option Cc: , , , , , , , , In-Reply-To: <1494309472-5691-3-git-send-email-bhe@redhat.com> References: <1494309472-5691-1-git-send-email-bhe@redhat.com> <1494309472-5691-3-git-send-email-bhe@redhat.com> Message-Id: <20170512131508.0AA2.61FB500B@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.73 [ja] X-TM-AS-MML: disable Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Baoquan, Thank you for fixing! I confirmed that the kernel is located within mem= address. Tested-by: Masayoshi Mizuma Regards, Masayoshi Mizuma On Tue, 9 May 2017 13:57:51 +0800 Baoquan He wrote: > Option mem= will limit the max address a system can use and any memory > region above the limit will be removed. > > Furthermore, memmap=nn[KMG] which has no offset specified has the same > behaviour as mem=. > > KASLR needs to consider this when choosing the random position for > decompressing the kernel. > > This patch implements that. > > Signed-off-by: Baoquan He > --- > arch/x86/boot/compressed/kaslr.c | 69 +++++++++++++++++++++++++++++----------- > 1 file changed, 51 insertions(+), 18 deletions(-) > > diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c > index 106e13b..0637e85 100644 > --- a/arch/x86/boot/compressed/kaslr.c > +++ b/arch/x86/boot/compressed/kaslr.c > @@ -88,6 +88,10 @@ struct mem_vector { > static bool memmap_too_large; > > > +/* Store memory limit specified by "mem=nn[KMG]" or "memmap=nn[KMG]" */ > +unsigned long long mem_limit = ULLONG_MAX; > + > + > enum mem_avoid_index { > MEM_AVOID_ZO_RANGE = 0, > MEM_AVOID_INITRD, > @@ -138,16 +142,24 @@ parse_memmap(char *p, unsigned long long *start, unsigned long long *size) > return -EINVAL; > > switch (*p) { > - case '@': > - /* Skip this region, usable */ > - *start = 0; > - *size = 0; > - return 0; > case '#': > case '$': > case '!': > *start = memparse(p + 1, &p); > return 0; > + case '@': /* Fall through: */ > + /* > + * memmap=nn@ss specifies usable region, should be skipped > + */ > + *size = 0; > + default: > + /* > + * If w/o offset, only size specified, memmap=nn[KMG] has the > + * same behaviour as mem=nn[KMG]. It limits the max address > + * system can use. Region above the limit should be avoided. > + */ > + *start = 0; > + return 0; > } > > return -EINVAL; > @@ -173,9 +185,14 @@ static void mem_avoid_memmap(char *str) > if (rc < 0) > break; > str = k; > - /* A usable region that should not be skipped */ > - if (size == 0) > + > + if (start == 0) { > + /* Store the specified memory limit if size > 0 */ > + if (size > 0) > + mem_limit = size; > + > continue; > + } > > mem_avoid[MEM_AVOID_MEMMAP_BEGIN + i].start = start; > mem_avoid[MEM_AVOID_MEMMAP_BEGIN + i].size = size; > @@ -187,19 +204,15 @@ static void mem_avoid_memmap(char *str) > memmap_too_large = true; > } > > - > -/* > - * handle_mem_memmap will also cover 'mem=' issue in next patch. Will remove > - * this note later. > - */ > static int handle_mem_memmap(void) > { > char *args = (char *)get_cmd_line_ptr(); > size_t len = strlen((char *)args); > char *tmp_cmdline; > char *param, *val; > + u64 mem_size; > > - if (!strstr(args, "memmap=")) > + if (!strstr(args, "memmap=") && !strstr(args, "mem=")) > return 0; > > tmp_cmdline = malloc(len + 1); > @@ -222,8 +235,20 @@ static int handle_mem_memmap(void) > return -1; > } > > - if (!strcmp(param, "memmap")) > + if (!strcmp(param, "memmap")) { > mem_avoid_memmap(val); > + } else if (!strcmp(param, "mem")) { > + char *p = val; > + > + if (!strcmp(p, "nopentium")) > + continue; > + mem_size = memparse(p, &p); > + if (mem_size == 0) { > + free(tmp_cmdline); > + return -EINVAL; > + } > + mem_limit = mem_size; > + } > } > > free(tmp_cmdline); > @@ -460,7 +485,8 @@ static void process_e820_entry(struct boot_e820_entry *entry, > { > struct mem_vector region, overlap; > struct slot_area slot_area; > - unsigned long start_orig; > + unsigned long start_orig, end; > + struct boot_e820_entry cur_entry; > > /* Skip non-RAM entries. */ > if (entry->type != E820_TYPE_RAM) > @@ -474,8 +500,15 @@ static void process_e820_entry(struct boot_e820_entry *entry, > if (entry->addr + entry->size < minimum) > return; > > - region.start = entry->addr; > - region.size = entry->size; > + /* Ignore entries above memory limit */ > + end = min(entry->size + entry->addr, mem_limit); > + if (entry->addr >= end) > + return; > + cur_entry.addr = entry->addr; > + cur_entry.size = end - entry->addr; > + > + region.start = cur_entry.addr; > + region.size = cur_entry.size; > > /* Give up if slot area array is full. */ > while (slot_area_index < MAX_SLOT_AREA) { > @@ -489,7 +522,7 @@ static void process_e820_entry(struct boot_e820_entry *entry, > region.start = ALIGN(region.start, CONFIG_PHYSICAL_ALIGN); > > /* Did we raise the address above this e820 region? */ > - if (region.start > entry->addr + entry->size) > + if (region.start > cur_entry.addr + cur_entry.size) > return; > > /* Reduce size by any delta from the original address. */ > -- > 2.5.5 >