Hi! > From: Rafael J. Wysocki <rjw@xxxxxxx> > > 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 <rjw@xxxxxxx> > --- > 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. > + */ Maybe this warning should be appended to struct saved_context definition? Reordering its fields (etc) would be bad news, too, and documentation near data structures is easier to find... Thanks, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
