[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>
diff --git a/arch/powerpc/mm/slb_low.S b/arch/powerpc/mm/slb_low.S
index 950ffc5..d1acee3 100644
--- a/arch/powerpc/mm/slb_low.S
+++ b/arch/powerpc/mm/slb_low.S
@@ -37,9 +37,9 @@
srdi r9,r3,60 /* get region */
srdi r10,r3,28 /* get esid */
- cmpldi cr7,r9,0xc /* cmp KERNELBASE for later use */
+ cmpldi cr7,r9,0xc /* cmp PAGE_OFFSET for later use */
- /* r3 = address, r10 = esid, cr7 = <>KERNELBASE */
+ /* r3 = address, r10 = esid, cr7 = <> PAGE_OFFSET */
blt cr7,0f /* user or kernel? */
/* kernel address: proto-VSID = ESID */
@@ -166,7 +166,7 @@
/*
* Finish loading of an SLB entry and return
*
- * r3 = EA, r10 = proto-VSID, r11 = flags, clobbers r9, cr7 = <>KERNELBASE
+ * r3 = EA, r10 = proto-VSID, r11 = flags, clobbers r9, cr7 = <> PAGE_OFFSET
*/
slb_finish_load:
ASM_VSID_SCRAMBLE(r10,r9)