powerpc/32: Add the ability for a classic ppc kernel to be loaded at 32M

Add the ability for a classic ppc kernel to be loaded at an address
of 32MB.  This done by fixing a few places that assume we are loaded
at address 0, and by changing several uses of KERNELBASE to use
PAGE_OFFSET, instead.

Signed-off-by: Dale Farnsworth <dale@farnsworth.org>
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 6 insertions, 5 deletions

diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index 266061924654..a1c4cfd25ded 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -183,7 +183,8 @@ __after_mmu_off:
         bl      reloc_offset
         mr      r26,r3
         addis   r4,r3,KERNELBASE@h      /* current address of _start */
-        cmpwi   0,r4,0                  /* are we already running at 0? */
+        lis     r5,PHYSICAL_START@h
+        cmplw   0,r4,r5                 /* already running at PHYSICAL_START? */
         bne     relocate_kernel
 /*
  * we now have the 1st 16M of ram mapped with the bats.
@@ -811,13 +812,13 @@ giveup_altivec:
 
 /*
  * This code is jumped to from the startup code to copy
- * the kernel image to physical address 0.
+ * the kernel image to physical address PHYSICAL_START.
  */
 relocate_kernel:
         addis   r9,r26,klimit@ha        /* fetch klimit */
         lwz     r25,klimit@l(r9)
         addis   r25,r25,-KERNELBASE@h
-        li      r3,0                    /* Destination base address */
+        lis     r3,PHYSICAL_START@h     /* Destination base address */
         li      r6,0                    /* Destination offset */
         li      r5,0x4000               /* # bytes of memory to copy */
         bl      copy_and_flush          /* copy the first 0x4000 bytes */
@@ -1188,11 +1189,11 @@ mmu_off:
 
 /*
  * Use the first pair of BAT registers to map the 1st 16MB
- * of RAM to KERNELBASE.  From this point on we can't safely
+ * of RAM to PAGE_OFFSET.  From this point on we can't safely
  * call OF any more.
  */
 initial_bats:
-        lis     r11,KERNELBASE@h
+        lis     r11,PAGE_OFFSET@h
         mfspr   r9,SPRN_PVR
         rlwinm  r9,r9,16,16,31          /* r9 = 1 for 601, 4 for 604 */
         cmpwi   0,r9,1