powerpc: make memremap_compat_align 64s-only

memremap_compat_align is only relevant when ZONE_DEVICE is selected.
ZONE_DEVICE depends on ARCH_HAS_PTE_DEVMAP, which is only selected
by PPC_BOOK3S_64.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211201144153.2456614-13-npiggin@gmail.com

arch/powerpc/Kconfig

@@ -129,7 +129,7 @@ config PPC
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_MEMBARRIER_CALLBACKS
 	select ARCH_HAS_MEMBARRIER_SYNC_CORE
-	select ARCH_HAS_MEMREMAP_COMPAT_ALIGN
+	select ARCH_HAS_MEMREMAP_COMPAT_ALIGN	if PPC_BOOK3S_64
 	select ARCH_HAS_MMIOWB			if PPC64
 	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
 	select ARCH_HAS_PHYS_TO_DMA

arch/powerpc/mm/book3s64/pgtable.c

@@ -528,3 +528,23 @@ static int __init pgtable_debugfs_setup(void)
 	return 0;
 }
 arch_initcall(pgtable_debugfs_setup);
+
+#ifdef CONFIG_ZONE_DEVICE
+/*
+ * Override the generic version in mm/memremap.c.
+ *
+ * With hash translation, the direct-map range is mapped with just one
+ * page size selected by htab_init_page_sizes(). Consult
+ * mmu_psize_defs[] to determine the minimum page size alignment.
+*/
+unsigned long memremap_compat_align(void)
+{
+	if (!radix_enabled()) {
+		unsigned int shift = mmu_psize_defs[mmu_linear_psize].shift;
+		return max(SUBSECTION_SIZE, 1UL << shift);
+	}
+
+	return SUBSECTION_SIZE;
+}
+EXPORT_SYMBOL_GPL(memremap_compat_align);
+#endif

arch/powerpc/mm/ioremap.c

@@ -98,23 +98,3 @@ void __iomem *do_ioremap(phys_addr_t pa, phys_addr_t offset, unsigned long size,
 
 	return NULL;
 }
-
-#ifdef CONFIG_ZONE_DEVICE
-/*
- * Override the generic version in mm/memremap.c.
- *
- * With hash translation, the direct-map range is mapped with just one
- * page size selected by htab_init_page_sizes(). Consult
- * mmu_psize_defs[] to determine the minimum page size alignment.
-*/
-unsigned long memremap_compat_align(void)
-{
-	unsigned int shift = mmu_psize_defs[mmu_linear_psize].shift;
-
-	if (radix_enabled())
-		return SUBSECTION_SIZE;
-	return max(SUBSECTION_SIZE, 1UL << shift);
-
-}
-EXPORT_SYMBOL_GPL(memremap_compat_align);
-#endif