[SRC] cvs commit: src/sys/i386/acpica acpi_wakeup.c src/sys/i386/i386 pmap.c

[Julian Elischer]

Nate Lawson wrote:
> Julian Elischer wrote:
>> Nate Lawson wrote:
>>> njl         2007-03-14 22:30:02 UTC
>>>
>>>   FreeBSD src repository
>>>
>>>   Modified files:
>>>     sys/i386/acpica      acpi_wakeup.c     sys/i386/i386        pmap.c
>>>   Log:
>>>   Create an identity mapping (V=P) super page for the low memory
>>> region on
>>>   boot.  Then, just switch to the kernel pmap when suspending instead of
>>>   allocating/freeing our own mapping every time.  This should solve a
>>> panic
>>>   of pmap_remove() being called with interrupts disabled.  Thanks to Alan
>>>   Cox for developing this patch.
>>>     Note: this means that ACPI requires super page (PG_PS) support in
>>> the CPU.
>>>   This has been present since the Pentium and first documented in the
>>>   Pentium Pro.  However, it may need to be revisited later.
>> I thought we were still supporting 486 class machines.
>> if so, shouldn't this be somehow ifdef'd?
> 
> Yes, that part needs to be covered although an ifdef is not necessary
> (PG_PS is defined for even 486's so this will compile).
> 
>>> Index: src/sys/i386/i386/pmap.c
>>> diff -u src/sys/i386/i386/pmap.c:1.582 src/sys/i386/i386/pmap.c:1.583
>>> --- src/sys/i386/i386/pmap.c:1.582    Mon Mar  5 21:40:10 2007
>>> +++ src/sys/i386/i386/pmap.c    Wed Mar 14 22:30:02 2007
>>> @@ -422,6 +422,13 @@
>>>  
>>>      /* Turn on PG_G on kernel page(s) */
>>>      pmap_set_pg();
>>> +
>>> +    /*
>>> +     * Create an identity mapping (virt == phys) for the low 1 MB
>>> +     * physical memory region that is used by the ACPI wakeup code.
>>> +     * This mapping must not have PG_G set. +     */
>>> +    kernel_pmap->pm_pdir[0] = PG_PS | PG_RW | PG_V;
>>>  }
>>>  
>>>  /*
> 
> I propose conditionalizing this code on "if (pseflag)".  Of course, the
> acpi suspend code will fail on 486's but we disable acpi entirely if the
> bios date < 1999/1/1 and acpi isn't supported on the 486.

as long as you are keeping this in mind, 
I have no objection as to how you tackle it..

so if someone uses a 486 based embedded system (low power etc.)
they can definitely not have any acpi support in the bios?



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