ARM: fix asm/memory.h build error

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: ca5a45c06c ("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>

arch/arm/include/asm/memory.h

@@ -100,23 +100,19 @@
 #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)
 
@@ -157,6 +153,16 @@
 #endif
 #define ARCH_PGD_MASK		((1 << ARCH_PGD_SHIFT) - 1)
 
+/*
+ * 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__
 
 /*
@@ -239,6 +245,8 @@ static inline unsigned long __phys_to_virt(phys_addr_t x)
 
 #else
 
+#define PHYS_OFFSET	PLAT_PHYS_OFFSET
+
 static inline phys_addr_t __virt_to_phys(unsigned long x)
 {
 	return (phys_addr_t)x - PAGE_OFFSET + PHYS_OFFSET;
@@ -251,17 +259,6 @@ static inline unsigned long __phys_to_virt(phys_addr_t x)
 
 #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

arch/arm/kernel/head-nommu.S

@@ -68,7 +68,7 @@ ENTRY(stext)
 
 #ifdef CONFIG_ARM_MPU
 	/* Calculate the size of a region covering just the kernel */
-	ldr	r5, =PHYS_OFFSET		@ Region start: PHYS_OFFSET
+	ldr	r5, =PLAT_PHYS_OFFSET		@ Region start: PHYS_OFFSET
 	ldr     r6, =(_end)			@ Cover whole kernel
 	sub	r6, r6, r5			@ Minimum size of region to map
 	clz	r6, r6				@ Region size must be 2^N...
@@ -213,7 +213,7 @@ ENTRY(__setup_mpu)
 	set_region_nr r0, #MPU_RAM_REGION
 	isb
 	/* Full access from PL0, PL1, shared for CONFIG_SMP, cacheable */
-	ldr	r0, =PHYS_OFFSET		@ RAM starts at PHYS_OFFSET
+	ldr	r0, =PLAT_PHYS_OFFSET		@ RAM starts at PHYS_OFFSET
 	ldr	r5,=(MPU_AP_PL1RW_PL0RW | MPU_RGN_NORMAL)
 
 	setup_region r0, r5, r6, MPU_DATA_SIDE	@ PHYS_OFFSET, shared, enabled

arch/arm/kernel/head.S

@@ -110,7 +110,7 @@ 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
 
 	/*