Re: [PATCH v2] x86: remove NX from video bios area

From: H. Peter Anvin
Date: Fri Nov 18 2011 - 00:03:17 EST


On 11/17/2011 08:45 PM, wangyanqing wrote:
> Sorry for my bad idea!

Don't worry... the important thing is that we have a real problem and
we're trying to figure it out.

> Indeed v86d have double backend to execute x86 video bios code,
> one is lrmi(linux real mode interface), another is x86emu.Yesterday,
> I compile the v86d with x86emu.Below is the new maps:
>
> 08048000-0805e000 r-xp 00000000 00:01 3324 /sbin/v86d
> 0805e000-0805f000 rw-p 00015000 00:01 3324 /sbin/v86d
> 0805f000-08060000 rw-p 00000000 00:00 0
> b7713000-b7733000 rw-s 000e0000 00:01 3234 /dev/mem
> b7733000-b7742000 rw-s 000c0000 00:01 3234 /dev/mem
> b7742000-b7762000 rw-s 000a0000 00:01 3234 /dev/mem
> b7762000-b7763000 rw-s 0009c000 00:01 3234 /dev/mem
> b7763000-b7764000 rw-s 00000000 00:01 3234 /dev/mem
> b7764000-b7784000 rw-p 00000000 00:01 3230 /dev/zero
> b7784000-b7785000 r-xp 00000000 00:00 0 [vdso]
> bf98a000-bf9ab000 rw-p 00000000 00:00 0 [stack]
>
> As you see, now v86d doesn't need the X permission.But
> my machine still hang very early(verbose show uvesafb some
> messages, then black screen, it hangs!)
>
> But if I make the BIOS range X unconditionally, the problem is gone.
> So we need more hacky.Any comment is welcome.

Is there any way you can hook up a serial console to your machine? I
suspect that we're getting a kernel panic that we're not seeing.

-hpa

--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.

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