Re: [Qemu-devel] Unknown symbol __PAGE_KERNEL_EXEC

[Pascal Terjan <pterjan@gmail.com>]

On 7/26/05, Darryl Dixon <esrever_otua@pythonhacker.is-a-geek.net> wrote:
> Hi All, Fabrice,
> 
>     Compiling the new kqemu-0.7.1 on Fedora Core 4 with kernel
> 2.6.12-1.1398_FC4 gives this error:
> 
> -------------8<-------------------
> [dixond@unixadmindazfc2 kqemu]$ make
> make -C /lib/modules/2.6.12-1.1398_FC4/build M=`pwd` modules
> make[1]: Entering directory `/usr/src/kernels/2.6.12-1.1398_FC4-i686'
>   CC [M]  /opt/src/qemu-0.7.1/kqemu/kqemu-linux.o
> cp /opt/src/qemu-0.7.1/kqemu/kqemu-mod-i386.o /opt/src/qemu-0.7.1/kqemu/kqemu-mod.o
>   LD [M]  /opt/src/qemu-0.7.1/kqemu/kqemu.o
>   Building modules, stage 2.
>   MODPOST
> Warning: could not find /opt/src/qemu-0.7.1/kqemu/.kqemu-mod.o.cmd
> for /opt/src/qemu-0.7.1/kqemu/kqemu-mod.o
> *** Warning: "__PAGE_KERNEL_EXEC" [/opt/src/qemu-0.7.1/kqemu/kqemu.ko]
> undefined!
>   CC      /opt/src/qemu-0.7.1/kqemu/kqemu.mod.o
>   LD [M]  /opt/src/qemu-0.7.1/kqemu/kqemu.ko
> make[1]: Leaving directory `/usr/src/kernels/2.6.12-1.1398_FC4-i686'

My understanding of the problem :
on i386, in pgtable.h we have
extern unsigned long long __PAGE_KERNEL, __PAGE_KERNEL_EXEC;
#define PAGE_KERNEL_EXEC        __pgprot(__PAGE_KERNEL_EXEC)

an there is EXPORT_SYMBOL(__PAGE_KERNEL) but not for __PAGE_KERNEL_EXEC

on x86_64 :
#define __PAGE_KERNEL_EXEC \
        (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED)
#define MAKE_GLOBAL(x) __pgprot((x) | _PAGE_GLOBAL)
#define PAGE_KERNEL_EXEC MAKE_GLOBAL(__PAGE_KERNEL_EXEC)

So, on i386 __PAGE_KERNEL_EXEC is an extern variable wich is not
exported and not a macro.

I wrote a patch on
http://www.zarb.org/cgi-bin/viewcvs.cgi/plf/SPECS/non-free/dkms-kqemu/kqemu-0.7.1-PAGE_KERNEL_EXEC.patch?rev=1.1&view=markup
but I don't know much kernel stuff so I have no idea how much it is
broken :-)