powerpc/mm: define empty update_mmu_cache() as static inline

Only BOOK3S and FSL_BOOK3E have a usefull update_mmu_cache().

For the others, just define it static inline.

In the meantime, simplify the FSL_BOOK3E related ifdef as
book3e_hugetlb_preload() only exists when CONFIG_PPC_FSL_BOOK3E
is selected.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/668aba4db6b9af6d8a151174e11a4289f1a6bbcd.1565933217.git.christophe.leroy@c-s.fr

arch/powerpc/include/asm/book3s/pgtable.h

@@ -26,5 +26,16 @@ extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 				     unsigned long size, pgprot_t vma_prot);
 #define __HAVE_PHYS_MEM_ACCESS_PROT
 
+/*
+ * This gets called at the end of handling a page fault, when
+ * the kernel has put a new PTE into the page table for the process.
+ * We use it to ensure coherency between the i-cache and d-cache
+ * for the page which has just been mapped in.
+ * On machines which use an MMU hash table, we use this to put a
+ * corresponding HPTE into the hash table ahead of time, instead of
+ * waiting for the inevitable extra hash-table miss exception.
+ */
+void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t *ptep);
+
 #endif /* __ASSEMBLY__ */
 #endif

arch/powerpc/include/asm/nohash/pgtable.h

@@ -293,5 +293,18 @@ static inline int pgd_huge(pgd_t pgd)
 #define is_hugepd(hpd)		(hugepd_ok(hpd))
 #endif
 
+/*
+ * This gets called at the end of handling a page fault, when
+ * the kernel has put a new PTE into the page table for the process.
+ * We use it to ensure coherency between the i-cache and d-cache
+ * for the page which has just been mapped in.
+ */
+#if defined(CONFIG_PPC_FSL_BOOK3E) && defined(CONFIG_HUGETLB_PAGE)
+void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t *ptep);
+#else
+static inline
+void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t *ptep) {}
+#endif
+
 #endif /* __ASSEMBLY__ */
 #endif

arch/powerpc/include/asm/pgtable.h

@@ -77,18 +77,6 @@ extern void paging_init(void);
 
 #include <asm-generic/pgtable.h>
 
-
-/*
- * This gets called at the end of handling a page fault, when
- * the kernel has put a new PTE into the page table for the process.
- * We use it to ensure coherency between the i-cache and d-cache
- * for the page which has just been mapped in.
- * On machines which use an MMU hash table, we use this to put a
- * corresponding HPTE into the hash table ahead of time, instead of
- * waiting for the inevitable extra hash-table miss exception.
- */
-extern void update_mmu_cache(struct vm_area_struct *, unsigned long, pte_t *);
-
 #ifndef CONFIG_TRANSPARENT_HUGEPAGE
 #define pmd_large(pmd)		0
 #endif

arch/powerpc/mm/mem.c

@@ -415,10 +415,10 @@ EXPORT_SYMBOL(flush_icache_user_range);
  * 
  * This must always be called with the pte lock held.
  */
+#ifdef CONFIG_PPC_BOOK3S
 void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
 		      pte_t *ptep)
 {
-#ifdef CONFIG_PPC_BOOK3S
 	/*
 	 * We don't need to worry about _PAGE_PRESENT here because we are
 	 * called with either mm->page_table_lock held or ptl lock held
@@ -456,13 +456,16 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
 	}
 
 	hash_preload(vma->vm_mm, address, is_exec, trap);
+}
 #endif /* CONFIG_PPC_BOOK3S */
-#if (defined(CONFIG_PPC_BOOK3E_64) || defined(CONFIG_PPC_FSL_BOOK3E)) \
-	&& defined(CONFIG_HUGETLB_PAGE)
+#if defined(CONFIG_PPC_FSL_BOOK3E) && defined(CONFIG_HUGETLB_PAGE)
+void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
+		      pte_t *ptep)
+{
 	if (is_vm_hugetlb_page(vma))
 		book3e_hugetlb_preload(vma, address, *ptep);
-#endif
 }
+#endif
 
 /*
  * System memory should not be in /proc/iomem but various tools expect it