powerpc/nohash: Refactor pte_update()

pte_update() is similar.

Take the nohash/32 version which works on nohash/64 and add the debug
call to assert_pte_locked() which is only on nohash/64.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/e01cb630cad42f645915ce7702d23985241b71fc.1695659959.git.christophe.leroy@csgroup.eu

arch/powerpc/include/asm/nohash/32/pgtable.h

@@ -9,8 +9,6 @@
 #include <linux/threads.h>
 #include <asm/mmu.h>			/* For sub-arch specific PPC_PIN_SIZE */
 
-extern int icache_44x_need_flush;
-
 #endif /* __ASSEMBLY__ */
 
 #define PTE_INDEX_SIZE	PTE_SHIFT
@@ -203,37 +201,6 @@ static inline void pmd_clear(pmd_t *pmdp)
 	*pmdp = __pmd(0);
 }
 
-/*
- * PTE updates. This function is called whenever an existing
- * valid PTE is updated. This does -not- include set_pte_at()
- * which nowadays only sets a new PTE.
- *
- * Depending on the type of MMU, we may need to use atomic updates
- * and the PTE may be either 32 or 64 bit wide. In the later case,
- * when using atomic updates, only the low part of the PTE is
- * accessed atomically.
- *
- * In addition, on 44x, we also maintain a global flag indicating
- * that an executable user mapping was modified, which is needed
- * to properly flush the virtually tagged instruction cache of
- * those implementations.
- */
-#ifndef pte_update
-static inline pte_basic_t pte_update(struct mm_struct *mm, unsigned long addr, pte_t *p,
-				     unsigned long clr, unsigned long set, int huge)
-{
-	pte_basic_t old = pte_val(*p);
-	pte_basic_t new = (old & ~(pte_basic_t)clr) | set;
-
-	*p = __pte(new);
-
-	if (IS_ENABLED(CONFIG_44x) && (old & _PAGE_USER) && (old & _PAGE_EXEC))
-		icache_44x_need_flush = 1;
-
-	return old;
-}
-#endif
-
 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
 static inline int __ptep_test_and_clear_young(struct mm_struct *mm,
 					      unsigned long addr, pte_t *ptep)

arch/powerpc/include/asm/nohash/64/pgtable.h

@@ -171,23 +171,6 @@ static inline void p4d_set(p4d_t *p4dp, unsigned long val)
 	*p4dp = __p4d(val);
 }
 
-/* Atomic PTE updates */
-static inline unsigned long pte_update(struct mm_struct *mm,
-				       unsigned long addr,
-				       pte_t *ptep, unsigned long clr,
-				       unsigned long set,
-				       int huge)
-{
-	unsigned long old = pte_val(*ptep);
-	*ptep = __pte((old & ~clr) | set);
-
-	/* huge pages use the old page table lock */
-	if (!huge)
-		assert_pte_locked(mm, addr);
-
-	return old;
-}
-
 static inline int pte_young(pte_t pte)
 {
 	return pte_val(pte) & _PAGE_ACCESSED;

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

@@ -2,6 +2,11 @@
 #ifndef _ASM_POWERPC_NOHASH_PGTABLE_H
 #define _ASM_POWERPC_NOHASH_PGTABLE_H
 
+#ifndef __ASSEMBLY__
+static inline pte_basic_t pte_update(struct mm_struct *mm, unsigned long addr, pte_t *p,
+				     unsigned long clr, unsigned long set, int huge);
+#endif
+
 #if defined(CONFIG_PPC64)
 #include <asm/nohash/64/pgtable.h>
 #else
@@ -18,6 +23,43 @@
 
 #ifndef __ASSEMBLY__
 
+extern int icache_44x_need_flush;
+
+/*
+ * PTE updates. This function is called whenever an existing
+ * valid PTE is updated. This does -not- include set_pte_at()
+ * which nowadays only sets a new PTE.
+ *
+ * Depending on the type of MMU, we may need to use atomic updates
+ * and the PTE may be either 32 or 64 bit wide. In the later case,
+ * when using atomic updates, only the low part of the PTE is
+ * accessed atomically.
+ *
+ * In addition, on 44x, we also maintain a global flag indicating
+ * that an executable user mapping was modified, which is needed
+ * to properly flush the virtually tagged instruction cache of
+ * those implementations.
+ */
+#ifndef pte_update
+static inline pte_basic_t pte_update(struct mm_struct *mm, unsigned long addr, pte_t *p,
+				     unsigned long clr, unsigned long set, int huge)
+{
+	pte_basic_t old = pte_val(*p);
+	pte_basic_t new = (old & ~(pte_basic_t)clr) | set;
+
+	*p = __pte(new);
+
+	if (IS_ENABLED(CONFIG_44x) && (old & _PAGE_USER) && (old & _PAGE_EXEC))
+		icache_44x_need_flush = 1;
+
+	/* huge pages use the old page table lock */
+	if (!huge)
+		assert_pte_locked(mm, addr);
+
+	return old;
+}
+#endif
+
 /* Generic accessors to PTE bits */
 #ifndef pte_write
 static inline int pte_write(pte_t pte)