[ARM] 3061/1: cleanup the XIP link address mess

Patch from Nicolas Pitre

Since vmlinux.lds.S is preprocessed, we can use the defines already
present in asm/memory.h (allowed by patch #3060) for the XIP kernel link
address instead of relying on a duplicated Makefile hardcoded value, and
also get rid of its dependency on awk to handle it at the same time.

While at it let's clean XIP stuff even further and make things clearer
in head.S with a nice code reduction.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/Makefile

@@ -8,7 +8,7 @@
 # Copyright (C) 1995-2001 by Russell King
 
 LDFLAGS_vmlinux	:=-p --no-undefined -X
-CPPFLAGS_vmlinux.lds = -DTEXTADDR=$(TEXTADDR) -DDATAADDR=$(DATAADDR)
+CPPFLAGS_vmlinux.lds = -DKERNEL_RAM_ADDR=$(TEXTADDR)
 OBJCOPYFLAGS	:=-O binary -R .note -R .comment -S
 GZFLAGS		:=-9
 #CFLAGS		+=-pipe
@@ -108,27 +108,19 @@ export CFLAGS_3c589_cs.o
 endif
 
 TEXTADDR := $(textaddr-y)
-ifeq ($(CONFIG_XIP_KERNEL),y)
-  DATAADDR := $(TEXTADDR)
-  xipaddr-$(CONFIG_ARCH_CO285) := 0x5f000000
-  xipaddr-y ?= 0xbf000000
-  # Replace phys addr with virt addr while keeping offset from base.
-  TEXTADDR := $(shell echo $(CONFIG_XIP_PHYS_ADDR) $(xipaddr-y) | \
-                      awk --non-decimal-data '/[:xdigit:]/ \
-                          { printf("0x%x\n", and($$1, 0x000fffff) + $$2) }' )
-endif
 
 ifeq ($(incdir-y),)
 incdir-y := $(machine-y)
 endif
 INCDIR   := arch-$(incdir-y)
+
 ifneq ($(machine-y),)
 MACHINE  := arch/arm/mach-$(machine-y)/
 else
 MACHINE  :=
 endif
 
-export	TEXTADDR DATAADDR GZFLAGS
+export	TEXTADDR GZFLAGS
 
 # Do we have FASTFPE?
 FASTFPE		:=arch/arm/fastfpe

arch/arm/kernel/Makefile

@@ -2,7 +2,7 @@
 # Makefile for the linux kernel.
 #
 
-AFLAGS_head.o := -DTEXTADDR=$(TEXTADDR) -DDATAADDR=$(DATAADDR)
+AFLAGS_head.o := -DKERNEL_RAM_ADDR=$(TEXTADDR)
 
 # Object file lists.
 

arch/arm/kernel/head.S

@@ -34,52 +34,28 @@
 #define MACHINFO_PGOFFIO	12
 #define MACHINFO_NAME		16
 
-#ifndef CONFIG_XIP_KERNEL
 /*
- * We place the page tables 16K below TEXTADDR.  Therefore, we must make sure
- * that TEXTADDR is correctly set.  Currently, we expect the least significant
- * 16 bits to be 0x8000, but we could probably relax this restriction to
- * TEXTADDR >= PAGE_OFFSET + 0x4000
- *
- * Note that swapper_pg_dir is the virtual address of the page tables, and
- * pgtbl gives us a position-independent reference to these tables.  We can
- * do this because stext == TEXTADDR
+ * swapper_pg_dir is the virtual address of the initial page table.
+ * We place the page tables 16K below KERNEL_RAM_ADDR.  Therefore, we must
+ * make sure that KERNEL_RAM_ADDR is correctly set.  Currently, we expect
+ * the least significant 16 bits to be 0x8000, but we could probably
+ * relax this restriction to KERNEL_RAM_ADDR >= PAGE_OFFSET + 0x4000.
  */
-#if (TEXTADDR & 0xffff) != 0x8000
-#error TEXTADDR must start at 0xXXXX8000
+#if (KERNEL_RAM_ADDR & 0xffff) != 0x8000
+#error KERNEL_RAM_ADDR must start at 0xXXXX8000
 #endif
 
 	.globl	swapper_pg_dir
-	.equ	swapper_pg_dir, TEXTADDR - 0x4000
+	.equ	swapper_pg_dir, KERNEL_RAM_ADDR - 0x4000
 
-	.macro	pgtbl, rd, phys
-	adr	\rd, stext
-	sub	\rd, \rd, #0x4000
+	.macro	pgtbl, rd
+	ldr	\rd, =(__virt_to_phys(KERNEL_RAM_ADDR - 0x4000))
 	.endm
-#else
-/*
- * XIP Kernel:
- *
- * We place the page tables 16K below DATAADDR.  Therefore, we must make sure
- * that DATAADDR is correctly set.  Currently, we expect the least significant
- * 16 bits to be 0x8000, but we could probably relax this restriction to
- * DATAADDR >= PAGE_OFFSET + 0x4000
- *
- * Note that pgtbl is meant to return the physical address of swapper_pg_dir.
- * We can't make it relative to the kernel position in this case since
- * the kernel can physically be anywhere.
- */
-#if (DATAADDR & 0xffff) != 0x8000
-#error DATAADDR must start at 0xXXXX8000
-#endif
-
-	.globl	swapper_pg_dir
-	.equ	swapper_pg_dir, DATAADDR - 0x4000
 
-	.macro	pgtbl, rd, phys
-	ldr	\rd, =((DATAADDR - 0x4000) - PAGE_OFFSET)
-	add	\rd, \rd, \phys
-	.endm
+#ifdef CONFIG_XIP_KERNEL
+#define TEXTADDR  XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR)
+#else
+#define TEXTADDR  KERNEL_RAM_ADDR
 #endif
 
 /*
@@ -280,7 +256,7 @@ __turn_mmu_on:
 	.type	__create_page_tables, %function
 __create_page_tables:
 	ldr	r5, [r8, #MACHINFO_PHYSRAM]	@ physram
-	pgtbl	r4, r5				@ page table address
+	pgtbl	r4				@ page table address
 
 	/*
 	 * Clear the 16K level 1 swapper page table

arch/arm/kernel/vmlinux.lds.S

@@ -6,14 +6,23 @@
 #include <asm-generic/vmlinux.lds.h>
 #include <linux/config.h>
 #include <asm/thread_info.h>
+#include <asm/memory.h>
 
 OUTPUT_ARCH(arm)
 ENTRY(stext)
+
 #ifndef __ARMEB__
 jiffies = jiffies_64;
 #else
 jiffies = jiffies_64 + 4;
 #endif
+
+#ifdef CONFIG_XIP_KERNEL
+#define TEXTADDR  XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR)
+#else
+#define TEXTADDR  KERNEL_RAM_ADDR
+#endif
+
 SECTIONS
 {
 	. = TEXTADDR;
@@ -95,7 +104,7 @@ SECTIONS
 
 #ifdef CONFIG_XIP_KERNEL
 	__data_loc = ALIGN(4);		/* location in binary */
-	. = DATAADDR;
+	. = KERNEL_RAM_ADDR;
 #else
 	. = ALIGN(THREAD_SIZE);
 	__data_loc = .;

include/asm-arm/memory.h

@@ -68,6 +68,13 @@
 #error Top of user space clashes with start of module space
 #endif
 
+/*
+ * The XIP kernel gets mapped at the bottom of the module vm area.
+ * Since we use sections to map it, this macro replaces the physical address
+ * with its virtual address while keeping offset from the base section.
+ */
+#define XIP_VIRT_ADDR(physaddr)  (MODULE_START + ((physaddr) & 0x000fffff))
+
 #ifndef __ASSEMBLY__
 
 /*