ARM: 7439/1: head.S: simplify initial page table mapping

Let's map the initial RAM up to the end of the kernel .bss instead of
the strict kernel image area.  This simplifies the code as the kernel
image only needs to be handled specially in the XIP case.  That covers
the legacy ATAG location as well.

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

arch/arm/kernel/head.S

@@ -55,14 +55,6 @@
 	add	\rd, \phys, #TEXT_OFFSET - PG_DIR_SIZE
 	.endm
 
-#ifdef CONFIG_XIP_KERNEL
-#define KERNEL_START	XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR)
-#define KERNEL_END	_edata_loc
-#else
-#define KERNEL_START	KERNEL_RAM_VADDR
-#define KERNEL_END	_end
-#endif
-
 /*
  * Kernel startup entry point.
  * ---------------------------
@@ -218,51 +210,46 @@ __create_page_tables:
 	blo	1b
 
 	/*
-	 * Now setup the pagetables for our kernel direct
-	 * mapped region.
+	 * Map our RAM from the start to the end of the kernel .bss section.
 	 */
-	mov	r3, pc
-	mov	r3, r3, lsr #SECTION_SHIFT
-	orr	r3, r7, r3, lsl #SECTION_SHIFT
-	add	r0, r4,  #(KERNEL_START & 0xff000000) >> (SECTION_SHIFT - PMD_ORDER)
-	str	r3, [r0, #((KERNEL_START & 0x00f00000) >> SECTION_SHIFT) << PMD_ORDER]!
-	ldr	r6, =(KERNEL_END - 1)
-	add	r0, r0, #1 << PMD_ORDER
+	add	r0, r4, #PAGE_OFFSET >> (SECTION_SHIFT - PMD_ORDER)
+	ldr	r6, =(_end - 1)
+	orr	r3, r8, r7
 	add	r6, r4, r6, lsr #(SECTION_SHIFT - PMD_ORDER)
-1:	cmp	r0, r6
+1:	str	r3, [r0], #1 << PMD_ORDER
 	add	r3, r3, #1 << SECTION_SHIFT
-	strls	r3, [r0], #1 << PMD_ORDER
+	cmp	r0, r6
 	bls	1b
 
 #ifdef CONFIG_XIP_KERNEL
 	/*
-	 * Map some ram to cover our .data and .bss areas.
+	 * Map the kernel image separately as it is not located in RAM.
 	 */
-	add	r3, r8, #TEXT_OFFSET
-	orr	r3, r3, r7
-	add	r0, r4,  #(KERNEL_RAM_VADDR & 0xff000000) >> (SECTION_SHIFT - PMD_ORDER)
-	str	r3, [r0, #(KERNEL_RAM_VADDR & 0x00f00000) >> (SECTION_SHIFT - PMD_ORDER)]!
-	ldr	r6, =(_end - 1)
-	add	r0, r0, #4
+#define XIP_START XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR)
+	mov	r3, pc
+	mov	r3, r3, lsr #SECTION_SHIFT
+	orr	r3, r7, r3, lsl #SECTION_SHIFT
+	add	r0, r4,  #(XIP_START & 0xff000000) >> (SECTION_SHIFT - PMD_ORDER)
+	str	r3, [r0, #((XIP_START & 0x00f00000) >> SECTION_SHIFT) << PMD_ORDER]!
+	ldr	r6, =(_edata_loc - 1)
+	add	r0, r0, #1 << PMD_ORDER
 	add	r6, r4, r6, lsr #(SECTION_SHIFT - PMD_ORDER)
 1:	cmp	r0, r6
-	add	r3, r3, #1 << 20
-	strls	r3, [r0], #4
+	add	r3, r3, #1 << SECTION_SHIFT
+	strls	r3, [r0], #1 << PMD_ORDER
 	bls	1b
 #endif
 
 	/*
-	 * Then map boot params address in r2 or the first 1MB (2MB with LPAE)
-	 * of ram if boot params address is not specified.
+	 * Then map boot params address in r2 if specified.
 	 */
 	mov	r0, r2, lsr #SECTION_SHIFT
 	movs	r0, r0, lsl #SECTION_SHIFT
-	moveq	r0, r8
-	sub	r3, r0, r8
-	add	r3, r3, #PAGE_OFFSET
-	add	r3, r4, r3, lsr #(SECTION_SHIFT - PMD_ORDER)
-	orr	r6, r7, r0
-	str	r6, [r3]
+	subne	r3, r0, r8
+	addne	r3, r3, #PAGE_OFFSET
+	addne	r3, r4, r3, lsr #(SECTION_SHIFT - PMD_ORDER)
+	orrne	r6, r7, r0
+	strne	r6, [r3]
 
 #ifdef CONFIG_DEBUG_LL
 #if !defined(CONFIG_DEBUG_ICEDCC) && !defined(CONFIG_DEBUG_SEMIHOSTING)