[Patch BUGFIX] kcore: fix its wrong size on x86_64

[Amerigo Wang <xiyou.wangcong@gmail.com>]

Fix wrong /proc/kcore size on x86_64.

x86_64 uses __va() macro to caculate the virtual address passed to kclist_add()
but decodes it with its own macro kc_vadd_to_offset(). This is wrong.

Also, according to Documentation/x86/x86_64/mm.txt, kc_vaddr_to_offset()
is wrong too.

So just remove them, use the generic macro.

BTW, the man page for /proc/kcore is wrong, its size can be more than
the physical memory size, because it also contains memory area of
vmalloc(), vsyscall etc...

Reported-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: WANG Cong <amwang@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>

---
diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h
index abde308..cdbfd1d 100644
--- a/arch/x86/include/asm/pgtable_64.h
+++ b/arch/x86/include/asm/pgtable_64.h
@@ -163,12 +163,6 @@ extern void cleanup_highmap(void);
 #define PAGE_AGP    PAGE_KERNEL_NOCACHE
 #define HAVE_PAGE_AGP 1
 
-/* fs/proc/kcore.c */
-#define	kc_vaddr_to_offset(v) ((v) & __VIRTUAL_MASK)
-#define	kc_offset_to_vaddr(o)				\
-	(((o) & (1UL << (__VIRTUAL_MASK_SHIFT - 1)))	\
-	 ? ((o) | ~__VIRTUAL_MASK)			\
-	 : (o))
 
 #define __HAVE_ARCH_PTE_SAME
 #endif /* !__ASSEMBLY__ */