hugetlb: introduce generic version of huge_ptep_get

ia64, mips, parisc, powerpc, sh, sparc, x86 architectures use the same
version of huge_ptep_get, so move this generic implementation into
asm-generic/hugetlb.h.

[[e-mail]: fix ARM 3level page tables]
Link: http://lkml.kernel.org/r/[e-mail]
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Alexandre Ghiti <[e-mail]>
Reviewed-by: Luiz Capitulino <[e-mail]>
Reviewed-by: Mike Kravetz <[e-mail]>
Tested-by: Helge Deller <[e-mail]> [parisc]
Acked-by: Catalin Marinas <[e-mail]> [arm64]
Acked-by: Paul Burton <[e-mail]> [MIPS]
Acked-by: Ingo Molnar <[e-mail]> [x86]
Cc: Arnd Bergmann <[e-mail]>
Cc: Benjamin Herrenschmidt <[e-mail]>
Cc: David S. Miller <[e-mail]>
Cc: Fenghua Yu <[e-mail]>
Cc: Heiko Carstens <[e-mail]>
Cc: H. Peter Anvin <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: James E.J. Bottomley <[e-mail]>
Cc: James Hogan <[e-mail]>
Cc: Martin Schwidefsky <[e-mail]>
Cc: Michael Ellerman <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
Cc: Ralf Baechle <[e-mail]>
Cc: Rich Felker <[e-mail]>
Cc: Russell King <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Tony Luck <[e-mail]>
Cc: Will Deacon <[e-mail]>
Cc: Yoshinori Sato <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

arch/arm/include/asm/hugetlb-3level.h

···
  * ptes.
  * (The valid bit is automatically cleared by set_pte_at for PROT_NONE ptes).
  */
+#define __HAVE_ARCH_HUGE_PTEP_GET
 static inline pte_t huge_ptep_get(pte_t *ptep)
 {
 	pte_t retval = *ptep;

arch/arm/include/asm/hugetlb.h

···
 #define _ASM_ARM_HUGETLB_H
 
 #include <asm/page.h>
-#include <asm-generic/hugetlb.h>
-
 #include <asm/hugetlb-3level.h>
+#include <asm-generic/hugetlb.h>
 
 static inline int is_hugepage_only_range(struct mm_struct *mm,
 					 unsigned long addr, unsigned long len)

arch/arm64/include/asm/hugetlb.h

···
 
 #include <asm/page.h>
 
+#define __HAVE_ARCH_HUGE_PTEP_GET
 static inline pte_t huge_ptep_get(pte_t *ptep)
 {
 	return READ_ONCE(*ptep);

arch/ia64/include/asm/hugetlb.h

···
 {
 }
 
-static inline pte_t huge_ptep_get(pte_t *ptep)
-{
-	return *ptep;
-}
-
 static inline void arch_clear_hugepage_flags(struct page *page)
 {
 }

arch/mips/include/asm/hugetlb.h

···
 	return changed;
 }
 
-static inline pte_t huge_ptep_get(pte_t *ptep)
-{
-	return *ptep;
-}
-
 static inline void arch_clear_hugepage_flags(struct page *page)
 {
 }

arch/parisc/include/asm/hugetlb.h

···
 					     unsigned long addr, pte_t *ptep,
 					     pte_t pte, int dirty);
 
-static inline pte_t huge_ptep_get(pte_t *ptep)
-{
-	return *ptep;
-}
-
 static inline void arch_clear_hugepage_flags(struct page *page)
 {
 }

arch/powerpc/include/asm/hugetlb.h

···
 				      unsigned long addr, pte_t *ptep,
 				      pte_t pte, int dirty);
 
-static inline pte_t huge_ptep_get(pte_t *ptep)
-{
-	return *ptep;
-}
-
 static inline void arch_clear_hugepage_flags(struct page *page)
 {
 }

arch/sh/include/asm/hugetlb.h

···
 {
 }
 
-static inline pte_t huge_ptep_get(pte_t *ptep)
-{
-	return *ptep;
-}
-
 static inline void arch_clear_hugepage_flags(struct page *page)
 {
 	clear_bit(PG_dcache_clean, &page->flags);

arch/sparc/include/asm/hugetlb.h

···
 	return changed;
 }
 
-static inline pte_t huge_ptep_get(pte_t *ptep)
-{
-	return *ptep;
-}
-
 static inline void arch_clear_hugepage_flags(struct page *page)
 {
 }

arch/x86/include/asm/hugetlb.h

···
 	return 0;
 }
 
-static inline pte_t huge_ptep_get(pte_t *ptep)
-{
-	return *ptep;
-}
-
 static inline void arch_clear_hugepage_flags(struct page *page)
 {
 }

include/asm-generic/hugetlb.h

···
 }
 #endif
 
+#ifndef __HAVE_ARCH_HUGE_PTEP_GET
+static inline pte_t huge_ptep_get(pte_t *ptep)
+{
+	return *ptep;
+}
+#endif
+
 #endif /* _ASM_GENERIC_HUGETLB_H */