On Wed, Aug 20, 2003 at 10:09:34AM -0700, Nate Lawson wrote: > I haven't had time to test your patch unfortunately but just wanted to let > you know of a corner case to be aware of. To suspend, ACPI maps in and > identity page table (phys == virt) and switches to real mode. I'm not > sure if your patches change the ability to access the first 1M or change > the way such a mapping would be done, but it would be useful if you > thought about this. The code is in /sys/i386/acpica/acpi_wakeup.c: > acpi_sleep_machdep(). A P==V mapping is also done during the startup of the APs on SMP. There should not be a problem. Also, this change loads the kernel at 0x400000 (so at the next 4M) just to be sure to not map that first 4M region in a 4M page, in particular to prevent from exposing holes in the region via a 4M page at any time. It should be noted that the changes leave the page tables describing the kernel with 4K-page ptes lying around in order to accomodate the P==V switchover in mp_machdep.c, so the legacy 4K page tables are still around, should they be required in a different mapping (like the mp_machdep one). In any case, it would still be nice if the acpi users (for whom acpi works for the most part) could give the patch a try as well (I have a decent-sized list of testers but would nonetheless welcome/appreciate more). > Thanks, > -Nate Cheers, -- Bosko Milekic * bmilekic_at_technokratis.com * bmilekic_at_FreeBSD.org TECHNOkRATIS Consulting Services * http://www.technokratis.com/Received on Wed Aug 20 2003 - 08:29:34 UTC
This archive was generated by hypermail 2.4.0 : Wed May 19 2021 - 11:37:19 UTC