Question on hugepages_supported()

In include/linux/hugetlb.h, we find the following statement

#ifndef hugepages_supported
/*
  * Some platform decide whether they support huge pages at boot
  * time. Some of them, such as powerpc, set HPAGE_SHIFT to 0
  * when there is no such support
  */
#define hugepages_supported() (HPAGE_SHIFT != 0)
#endif

But in arch/powerpc/include/asm/page.h we find:

#ifdef CONFIG_HUGETLB_PAGE
extern unsigned int HPAGE_SHIFT;
#else
#define HPAGE_SHIFT PAGE_SHIFT
#endif


Is that correct ? SHouldn't HPAGE_SHIFT be defined to 0 when 
CONFIG_HUGETLB_PAGE is not defined ?

Christophe