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From: Ingo Molnar <>
To: Andi Kleen <>
Subject: Re: [PATCH] Fix left over EFI cache mapping problems
Date: Thu, 14 Feb 2008 19:38:19 +0100	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

* Andi Kleen <> wrote:

> > this is indeed a bug (we change the attributes for a larger area 
> > than needed), but your fix is unclean. Find below a cleaner 
> > solution.
> You're still ignoring the other problem of set_memory_uc() not 
> handling fixmap and ioremap correctly. [...]

No, we did not ignore it, and yes, you are wrong.

One thing that you miss is that the 64-bit EFI runtime has to be marked 
uncacheable only if it the EFI image attribute signals an uncacheable 

                if (!(md->attribute & EFI_MEMORY_WB))
                        set_memory_uc(md->virt_addr, md->num_pages);

and Linux EFI does not support device EFI runtimes. So your observation, 
while correct for non-RAM 64-bit EFI images, is theoretical at the 
moment and has no practical relevance.

Of course, as we've stated it numerous times, we want this all fixed up, 
and we _have_ fixed it up already, but we wanted to do it properly. 
Right now we've got the fixes lined up and we are waiting for a test 
report and an Ack from Ying Huang. (he reported that current -git worked 
just fine for him)

Also note that 64-bit EFI runtime support (the ability to execute EFI 
code) is completely new - it got introduced 14 days ago. We only use 
fixmaps on 64-bit EFI.

32-bit EFI is more common (but still not very common, compared to other 
x86 platforms) and that is totally unaffected by secondary aliases. 
(which is a complication of the 64-bit kernel)



  reply	other threads:[~2008-02-14 18:38 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-14 13:13 Andi Kleen
2008-02-14 16:12 ` Ingo Molnar
2008-02-14 17:16   ` Andi Kleen
2008-02-14 18:38     ` Ingo Molnar [this message]
2008-02-14 21:42       ` Andi Kleen
2008-02-14 22:08         ` Arjan van de Ven
2008-02-14 23:01           ` Andi Kleen
2008-02-15  2:52       ` Huang, Ying
2008-02-15  8:55         ` Andi Kleen
2008-02-15  9:16           ` Huang, Ying
2008-02-15  4:48   ` Huang, Ying
2008-02-15  5:44     ` Linus Torvalds
2008-02-15  6:24       ` Huang, Ying
2008-02-15  7:30       ` Ingo Molnar
2008-02-15  7:08     ` Ingo Molnar
2008-02-15  7:32       ` Huang, Ying
2008-02-18  1:53       ` Huang, Ying
2008-02-18 11:26         ` Andi Kleen
2008-02-18 14:05           ` Ingo Molnar
2008-02-15  8:48     ` Andi Kleen
2008-02-15  9:21       ` Huang, Ying
2008-02-15  9:43         ` Andi Kleen

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