Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753807AbXL1MeW (ORCPT ); Fri, 28 Dec 2007 07:34:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752242AbXL1MeN (ORCPT ); Fri, 28 Dec 2007 07:34:13 -0500 Received: from ogre.sisk.pl ([217.79.144.158]:47734 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752059AbXL1MeM (ORCPT ); Fri, 28 Dec 2007 07:34:12 -0500 From: "Rafael J. Wysocki" To: pm list Subject: [PATCH] Hibernation: Document __save_processor_state() on x86-64 Date: Fri, 28 Dec 2007 13:53:37 +0100 User-Agent: KMail/1.9.6 (enterprise 20070904.708012) Cc: Andrew Morton , Ingo Molnar , Len Brown , LKML , Pavel Machek MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-2" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200712281353.37976.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2174 Lines: 54 From: Rafael J. Wysocki Document the fact that __save_processor_state() has to save all CPU registers referred to by the kernel in case a different kernel is used to load and restore a hibernation image containing it. Sigend-off-by: Rafael J. Wysocki --- arch/x86/kernel/suspend_64.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) Index: linux-2.6/arch/x86/kernel/suspend_64.c =================================================================== --- linux-2.6.orig/arch/x86/kernel/suspend_64.c +++ linux-2.6/arch/x86/kernel/suspend_64.c @@ -19,6 +19,21 @@ extern const void __nosave_begin, __nosa struct saved_context saved_context; +/** + * __save_processor_state - save CPU registers before creating a + * hibernation image and before restoring the memory state from it + * @ctxt - structure to store the registers contents in + * + * NOTE: If there is a CPU register the modification of which by the + * boot kernel (ie. the kernel used for loading the hibernation image) + * might affect the operations of the restored target kernel (ie. the one + * saved in the hibernation image), then its contents must be saved by this + * function. In other words, if kernel A is hibernated and different + * kernel B is used for loading the hibernation image into memory, the + * kernel A's __save_processor_state() function must save all registers + * needed by kernel A, so that it can operate correctly after the resume + * regardless of what kernel B does in the meantime. + */ void __save_processor_state(struct saved_context *ctxt) { kernel_fpu_begin(); @@ -69,6 +84,11 @@ static void do_fpu_end(void) kernel_fpu_end(); } +/** + * __restore_processor_state - restore the contents of CPU registers saved + * by __save_processor_state() + * @ctxt - structure to load the registers contents from + */ void __restore_processor_state(struct saved_context *ctxt) { /* -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/