Re: [PATCH] x86: Construct 32 bit boot time page tables in native format.

["H. Peter Anvin" <hpa@zytor.com>]

Rafael J. Wysocki wrote:
> On Monday, 28 of January 2008, Pavel Machek wrote:
>> Hi!
>>
>>>>>  /*
>>>>>   * Swap suspend & friends need this for resume because things like the intel-agp
>>>>>   * driver might have split up a kernel 4MB mapping.
>>>>>   */
>>>>> -char __nosavedata swsusp_pg_dir[PAGE_SIZE]
>>>>> +char swsusp_pg_dir[PAGE_SIZE]
>>>> thanks, applied.
>> Sorry, this is subtle and I've overlooked it before.
>>
>> (I thought you were only changing ifdef).
>>
>> Now you memcpy() over pg_dir when that pgdir is in use during swsusp
>> resume.
> 
> It is not.  swsusp hasn't been using swsusp_pg_dir for several months.
> Hence, the patch. :-)
> 
>> Granted, you memcpy() with same data that already are there, 
>> but it may still do some funny effects.
>>
>> Hmm, but same argument applies to lower levels of paging in 64-bit and
>> PAE cases, and we still do that memcpy-over-active-pagetables there...
>> :-(.
> 
> Actually, no.  We only do that with the kernel code mapping which should be
> safe as long as TLBs are not flushed (and they aren't).
> 

Okay... does that in any way affect using the kernel code mapping 
synchronization code to maintain a set of trampoline pagetables?

	-hpa