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>

1 files changed, 23 insertions, 36 deletions

diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 835898e7d704..3db960e20cb8 100644
--- a/arch/arm/kernel/head.S
+++ b/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)