From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [RFC][PATCH -mm 3/4] Hibernation: Use temporary kernel text mapping during restore on x86_64 Date: Tue, 21 Aug 2007 09:59:04 +0200 Message-ID: <20070821075904.GG7258@elf.ucw.cz> References: <200708201510.03734.rjw@sisk.pl> <200708201517.25622.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <200708201517.25622.rjw@sisk.pl> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: "Rafael J. Wysocki" Cc: discuss@x86-64.org, pm list , Nigel Cunningham List-Id: linux-pm@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. > > Signed-off-by: Rafael J. Wysocki > --- > arch/x86_64/kernel/suspend.c | 41 ++++++++++++++++++++++++++++++++++------- > 1 file changed, 34 insertions(+), 7 deletions(-) > > Index: linux-2.6.23-rc3/arch/x86_64/kernel/suspend.c > =================================================================== > --- linux-2.6.23-rc3.orig/arch/x86_64/kernel/suspend.c 2007-08-14 01:06:28.000000000 +0200 > +++ linux-2.6.23-rc3/arch/x86_64/kernel/suspend.c 2007-08-14 01:06:34.000000000 +0200 > @@ -175,7 +175,7 @@ static int res_phys_pud_init(pud_t *pud, > > if (paddr >= end) > break; > - pe = _PAGE_NX | _PAGE_PSE | _KERNPG_TABLE | paddr; > + pe = __PAGE_KERNEL_LARGE | paddr; > pe &= __supported_pte_mask; > set_pmd(pmd, __pmd(pe)); > } > @@ -183,25 +183,42 @@ 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) { Should we have something like "< max possible kernel size here"? IOW this needs to cover both suspend _and_ resume kernels, no? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html