From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763539AbXHVPFf (ORCPT ); Wed, 22 Aug 2007 11:05:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761127AbXHVPF0 (ORCPT ); Wed, 22 Aug 2007 11:05:26 -0400 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:39638 "EHLO amd.ucw.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1761181AbXHVPFZ (ORCPT ); Wed, 22 Aug 2007 11:05:25 -0400 Date: Wed, 22 Aug 2007 10:29:48 +0200 From: Pavel Machek To: "Rafael J. Wysocki" Cc: Andi Kleen , LKML , pm list Subject: Re: [RFC][PATCH -mm 4/4] Hibernation: Use temporary page tables for kernel text mapping on x86_64 Message-ID: <20070822082948.GD2479@elf.ucw.cz> References: <200708221015.16493.rjw@sisk.pl> <200708221021.28877.rjw@sisk.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200708221021.28877.rjw@sisk.pl> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.11+cvs20060126 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > Use temporary page tables for the kernel text mapping during hibernation restore > on x86_64. > > Without the patch, the original boot kernel's page tables that represent the > kernel text mapping are used while the core of the image kernel is being > restored. However, in principle, if the boot kernel is not identical to the > image kernel, the location of these page tables in the image kernel need not be > the same, so we should create a safe copy of the kernel text mapping prior to > restoring the core of the image kernel. > @@ -190,25 +190,42 @@ static int res_phys_pud_init(pud_t *pud, > return 0; > } > > +static int res_kernel_text_pud_init(pud_t *pud, unsigned long start) > +{ > + pmd_t *pmd; > + unsigned long paddr; > + > + pmd = (pmd_t *)get_safe_page(GFP_ATOMIC); > + if (!pmd) > + return -ENOMEM; > + set_pud(pud + pud_index(start), __pud(__pa(pmd) | _KERNPG_TABLE)); > + for (paddr = 0; paddr < KERNEL_TEXT_SIZE; pmd++, paddr += PMD_SIZE) { > + unsigned long pe; > + > + pe = __PAGE_KERNEL_LARGE_EXEC | _PAGE_GLOBAL | paddr; > + pe &= __supported_pte_mask; > + set_pmd(pmd, __pmd(pe)); > + } > + > + return 0; > +} > + > static int set_up_temporary_mappings(void) > { > unsigned long start, end, next; > + pud_t *pud; > int error; > > temp_level4_pgt = (pgd_t *)get_safe_page(GFP_ATOMIC); > if (!temp_level4_pgt) > return -ENOMEM; > > - /* It is safe to reuse the original kernel mapping */ > - set_pgd(temp_level4_pgt + pgd_index(__START_KERNEL_map), > - init_level4_pgt[pgd_index(__START_KERNEL_map)]); > - > /* Set up the direct mapping from scratch */ > start = (unsigned long)pfn_to_kaddr(0); > end = (unsigned long)pfn_to_kaddr(end_pfn); > > for (; start < end; start = next) { > - pud_t *pud = (pud_t *)get_safe_page(GFP_ATOMIC); > + pud = (pud_t *)get_safe_page(GFP_ATOMIC); > if (!pud) > return -ENOMEM; I believe we leak temp_level4_pgt here. > + /* Set up the kernel text mapping from scratch */ > + pud = (pud_t *)get_safe_page(GFP_ATOMIC); > + if (!pud) > + return -ENOMEM; ...and some more memory here :-(. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html