Convert virtual address to physical address

[Pratik Singhal]

I need to convert a kernel virtual address to physical address. To do that,
as far as I know, we have 2 macros :-

vtophys :- In sys/arm/include/pmap.h
VTOP :- In sys/boot/i386/libi386/amd64_tramp.S

Since, I am working on arm kernel with ARM_NEW_PMAP option, I am using
vtophys macro by including the pmap.h file.

Now, if I compile the kernel after including the pmap.h file, I am getting
the error :-

error: field has incomplete type 'struct pmap_statistics'
        struct pmap_statistics  pm_stats;       /* pmap statictics */
                                ^
./machine/pmap-v6.h:127:9: note: forward declaration of 'struct
pmap_statistics'
        struct pmap_statistics  pm_stats;       /* pmap statictics */

How, should I resolve this error ? Or is there some other way to convert
virtual address to physical address for arm kernel ?