ARM: fix asm/memory.h build error

commit b713aa0b upstream.

Jason Gunthorpe reports a build failure when ARM_PATCH_PHYS_VIRT is
not defined:

In file included from arch/arm/include/asm/page.h:163:0,
                 from include/linux/mm_types.h:16,
                 from include/linux/sched.h:24,
                 from arch/arm/kernel/asm-offsets.c:13:
arch/arm/include/asm/memory.h: In function '__virt_to_phys':
arch/arm/include/asm/memory.h:244:40: error: 'PHYS_OFFSET' undeclared (first use in this function)
arch/arm/include/asm/memory.h:244:40: note: each undeclared identifier is reported only once for each function it appears in
arch/arm/include/asm/memory.h: In function '__phys_to_virt':
arch/arm/include/asm/memory.h:249:13: error: 'PHYS_OFFSET' undeclared (first use in this function)

Fixes: ca5a45c0 ("ARM: mm: use phys_addr_t appropriately in p2v and v2p conversions")
Tested-By: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
[hpy: Backported to 3.10:
 - adjust the context
 - MPU is not supported by 3.10, so ignore fix to MPU compared with the original patch.]
Signed-off-by: Hou Pengyang <houpengyang@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/arm/include/asm/memory.h

@@ -98,23 +98,19 @@
 #define TASK_UNMAPPED_BASE	UL(0x00000000)
 #endif
 
-#ifndef PHYS_OFFSET
-#define PHYS_OFFSET 		UL(CONFIG_DRAM_BASE)
-#endif
-
 #ifndef END_MEM
 #define END_MEM     		(UL(CONFIG_DRAM_BASE) + CONFIG_DRAM_SIZE)
 #endif
 
 #ifndef PAGE_OFFSET
-#define PAGE_OFFSET		(PHYS_OFFSET)
+#define PAGE_OFFSET		PLAT_PHYS_OFFSET
 #endif
 
 /*
  * The module can be at any place in ram in nommu mode.
  */
 #define MODULES_END		(END_MEM)
-#define MODULES_VADDR		(PHYS_OFFSET)
+#define MODULES_VADDR		PAGE_OFFSET
 
 #define XIP_VIRT_ADDR(physaddr)  (physaddr)
 
@@ -141,6 +137,16 @@
 #define page_to_phys(page)	(__pfn_to_phys(page_to_pfn(page)))
 #define phys_to_page(phys)	(pfn_to_page(__phys_to_pfn(phys)))
 
+/*
+ * PLAT_PHYS_OFFSET is the offset (from zero) of the start of physical
+ * memory.  This is used for XIP and NoMMU kernels, or by kernels which
+ * have their own mach/memory.h.  Assembly code must always use
+ * PLAT_PHYS_OFFSET and not PHYS_OFFSET.
+ */
+#ifndef PLAT_PHYS_OFFSET
+#define PLAT_PHYS_OFFSET	UL(CONFIG_PHYS_OFFSET)
+#endif
+
 #ifndef __ASSEMBLY__
 
 /*
@@ -183,22 +189,15 @@ static inline unsigned long __phys_to_virt(unsigned long x)
 	return t;
 }
 #else
+
+#define PHYS_OFFSET	PLAT_PHYS_OFFSET
+
 #define __virt_to_phys(x)	((x) - PAGE_OFFSET + PHYS_OFFSET)
 #define __phys_to_virt(x)	((x) - PHYS_OFFSET + PAGE_OFFSET)
-#endif
-#endif
-#endif /* __ASSEMBLY__ */
 
-#ifndef PHYS_OFFSET
-#ifdef PLAT_PHYS_OFFSET
-#define PHYS_OFFSET	PLAT_PHYS_OFFSET
-#else
-#define PHYS_OFFSET	UL(CONFIG_PHYS_OFFSET)
 #endif
 #endif
 
-#ifndef __ASSEMBLY__
-
 /*
  * PFNs are used to describe any physical page; this means
  * PFN 0 == physical address 0.

arch/arm/kernel/head.S

@@ -109,7 +109,7 @@ ENTRY(stext)
 	sub	r4, r3, r4			@ (PHYS_OFFSET - PAGE_OFFSET)
 	add	r8, r8, r4			@ PHYS_OFFSET
 #else
-	ldr	r8, =PHYS_OFFSET		@ always constant in this case
+	ldr	r8, =PLAT_PHYS_OFFSET		@ always constant in this case
 #endif
 
 	/*