mp_machdep.c (was Re: [Fwd: Re: Bug reports requested - acpi])

Roman Kurakin rik at
Wed Sep 22 00:56:07 PDT 2004

Nate Lawson:

> John Baldwin wrote:
>> On Tuesday 21 September 2004 01:10 pm, Nate Lawson wrote:
>>> A quick "no" vote from me until this is really understood.  I think the
>>> real problem is an interference between the pmap for the AP trampoline
>>> and the acpi wake code (sys/i386/acpica/acpi_wakeup.c).  The address 
>>> you
>>> gave (0x9f000) is right before the base address we use for the wakeup
>>> code (0xa0000).  As I woke up this morning, I was wondering if this
>>> could be the issue.  An easy way to test is to disable the call to
>>> acpi_install_wakeup_handler() in sys/i386/acpica/acpi_machdep.c and see
>>> if this alone fixes the problem.
>>> If I'm wrong, feel free to commit your patch.
>>> P.S. Spaces instead of tabs in your diff.
>> Umm, 0xa0000 is the start of Video RAM, so I sure hope the ACPI wake 
>> code doesn't try to write code into Video memory.  The 
>> pmap_invalidate_page is certainly needed.
> This call to alloc the memory seems to say 0xa0000 is the first valid 
> start address:
> if (bus_dma_tag_create(/* parent */ NULL, /* alignment */ 2, 0,
>     /* lowaddr below 1MB */ 0x9ffff,
>     /* highaddr */ BUS_SPACE_MAXADDR, NULL, NULL,
>     PAGE_SIZE, 1, PAGE_SIZE, 0, busdma_lock_mutex,
>     &Giant, &acpi_waketag) != 0)
> In any case, you're right about needing to invalidate the mapping 
> after creating it so feel free to commit.  Do we also need this after 
> pmap_enter() in acpi_sleep_machdep() (i386/acpica/acpi_wakeup.c)? 

No, a quick view tells that pmap_enter() do this by it self.
In my case pmap_kenter ().



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