[PATCH] powerpc: Separate usage of KERNELBASE and PAGE_OFFSET

This patch separates usage of KERNELBASE and PAGE_OFFSET. I haven't
looked at any of the PPC32 code, if we ever want to support Kdump on
PPC we'll have to do another audit, ditto for iSeries.

This patch makes PAGE_OFFSET the constant, it'll always be 0xC * 1
gazillion for 64-bit.

To get a physical address from a virtual one you subtract PAGE_OFFSET,
_not_ KERNELBASE.

KERNELBASE is the virtual address of the start of the kernel, it's
often the same as PAGE_OFFSET, but _might not be_.

If you want to know something's offset from the start of the kernel
you should subtract KERNELBASE.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 7b9397169709..aacebb33e98a 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -690,7 +690,7 @@ _GLOBAL(enter_rtas)
 
         /* Setup our real return addr */        
         SET_REG_TO_LABEL(r4,.rtas_return_loc)
-        SET_REG_TO_CONST(r9,KERNELBASE)
+        SET_REG_TO_CONST(r9,PAGE_OFFSET)
         sub     r4,r4,r9
         mtlr    r4
 
@@ -718,7 +718,7 @@ _GLOBAL(enter_rtas)
 _STATIC(rtas_return_loc)
         /* relocation is off at this point */
         mfspr   r4,SPRN_SPRG3           /* Get PACA */
-        SET_REG_TO_CONST(r5, KERNELBASE)
+        SET_REG_TO_CONST(r5, PAGE_OFFSET)
         sub     r4,r4,r5                /* RELOC the PACA base pointer */
 
         mfmsr   r6