kallsyms: Clean up x86-64 special casing of in_gate_area()

x86-64 has special case code for in_gate_area(), but it is not clean.

* Replace CONFIG_ARCH_GATE_AREA with __HAVE_ARCH_GATE_AREA.
  ARCH_GATE_AREA is not a config option.

* The definitions of get_gate_vma() and in_gate_area() are identical in
  include/asm-x86_64/page.h and include/linux/mm.h.  Fold the duplicate
  definitions into include/linux/mm.h.

Does not affect kallsyms directly, this patch just creates a clean base
for patch 2.
Signed-off-by: Keith Owens <kaos@ocs.com.au>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

include/asm-x86_64/page.h

@@ -134,13 +134,7 @@ extern __inline__ int get_order(unsigned long size)
 	(((current->personality & READ_IMPLIES_EXEC) ? VM_EXEC : 0 ) | \
 	 VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
 
-#define CONFIG_ARCH_GATE_AREA 1	
-
-#ifndef __ASSEMBLY__
-struct task_struct;
-struct vm_area_struct *get_gate_vma(struct task_struct *tsk);
-int in_gate_area(struct task_struct *task, unsigned long addr);
-#endif
+#define __HAVE_ARCH_GATE_AREA 1	
 
 #endif /* __KERNEL__ */
 

include/linux/mm.h

@@ -799,10 +799,8 @@ kernel_map_pages(struct page *page, int numpages, int enable)
 }
 #endif
 
-#ifndef CONFIG_ARCH_GATE_AREA
 extern struct vm_area_struct *get_gate_vma(struct task_struct *tsk);
 int in_gate_area(struct task_struct *task, unsigned long addr);
-#endif
 
 #endif /* __KERNEL__ */
 #endif /* _LINUX_MM_H */

mm/memory.c

@@ -1811,7 +1811,7 @@ unsigned long vmalloc_to_pfn(void * vmalloc_addr)
 
 EXPORT_SYMBOL(vmalloc_to_pfn);
 
-#if !defined(CONFIG_ARCH_GATE_AREA)
+#if !defined(__HAVE_ARCH_GATE_AREA)
 
 #if defined(AT_SYSINFO_EHDR)
 struct vm_area_struct gate_vma;
@@ -1846,4 +1846,4 @@ int in_gate_area(struct task_struct *task, unsigned long addr)
 	return 0;
 }
 
-#endif
+#endif	/* __HAVE_ARCH_GATE_AREA */