m68k/mm: enable use of generic memory_model.h for !DISCONTIGMEM

The pg_data_map and pg_data_table arrays as well as page_to_pfn() and
pfn_to_page() are required only for DISCONTIGMEM. Other memory models can
use the generic definitions in asm-generic/memory_model.h.

Link: https://lkml.kernel.org/r/20201101170454.9567-13-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Meelis Roos <mroos@linux.ee>
Cc: Michael Schmitz <schmitzmic@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/m68k/Kconfig.cpu

@@ -374,7 +374,6 @@ config SINGLE_MEMORY_CHUNK
 	bool "Use one physical chunk of memory only" if ADVANCED && !SUN3
 	depends on MMU
 	default y if SUN3 || MMU_COLDFIRE
-	select NEED_MULTIPLE_NODES
 	help
 	  Ignore all but the first contiguous chunk of physical memory for VM
 	  purposes.  This will save a few bytes kernel size and may speed up

arch/m68k/include/asm/page.h

@@ -62,8 +62,10 @@ extern unsigned long _ramend;
 #include <asm/page_no.h>
 #endif
 
+#ifdef CONFIG_DISCONTIGMEM
 #define __phys_to_pfn(paddr)	((unsigned long)((paddr) >> PAGE_SHIFT))
 #define __pfn_to_phys(pfn)	PFN_PHYS(pfn)
+#endif
 
 #include <asm-generic/getorder.h>
 

arch/m68k/include/asm/page_mm.h

@@ -153,6 +153,7 @@ static inline __attribute_const__ int __virt_to_node_shift(void)
 	pfn_to_virt(page_to_pfn(page));					\
 })
 
+#ifdef CONFIG_DISCONTIGMEM
 #define pfn_to_page(pfn) ({						\
 	unsigned long __pfn = (pfn);					\
 	struct pglist_data *pgdat;					\
@@ -165,6 +166,10 @@ static inline __attribute_const__ int __virt_to_node_shift(void)
 	pgdat = &pg_data_map[page_to_nid(__p)];				\
 	((__p) - pgdat->node_mem_map) + pgdat->node_start_pfn;		\
 })
+#else
+#define ARCH_PFN_OFFSET (m68k_memory[0].addr)
+#include <asm-generic/memory_model.h>
+#endif
 
 #define virt_addr_valid(kaddr)	((void *)(kaddr) >= (void *)PAGE_OFFSET && (void *)(kaddr) < high_memory)
 #define pfn_valid(pfn)		virt_addr_valid(pfn_to_virt(pfn))

arch/m68k/include/asm/virtconvert.h

@@ -29,12 +29,7 @@ static inline void *phys_to_virt(unsigned long address)
 }
 
 /* Permanent address of a page. */
-#if defined(CONFIG_MMU) && !defined(CONFIG_DISCONTIGMEM)
-#define page_to_phys(page) \
-	__pa(PAGE_OFFSET + (((page) - pg_data_map[0].node_mem_map) << PAGE_SHIFT))
-#else
 #define page_to_phys(page)	(page_to_pfn(page) << PAGE_SHIFT)
-#endif
 
 /*
  * IO bus memory addresses are 1:1 with the physical address,

arch/m68k/mm/init.c

@@ -42,12 +42,12 @@ EXPORT_SYMBOL(empty_zero_page);
 
 #ifdef CONFIG_MMU
 
-pg_data_t pg_data_map[MAX_NUMNODES];
-EXPORT_SYMBOL(pg_data_map);
-
 int m68k_virt_to_node_shift;
 
 #ifdef CONFIG_DISCONTIGMEM
+pg_data_t pg_data_map[MAX_NUMNODES];
+EXPORT_SYMBOL(pg_data_map);
+
 pg_data_t *pg_data_table[65];
 EXPORT_SYMBOL(pg_data_table);
 #endif