[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>

arch/powerpc/kernel/lparmap.c

@@ -16,8 +16,8 @@ const struct LparMap __attribute__((__section__(".text"))) xLparMap = {
 	.xSegmentTableOffs = STAB0_PAGE,
 
 	.xEsids = {
-		{ .xKernelEsid = GET_ESID(KERNELBASE),
-		  .xKernelVsid = KERNEL_VSID(KERNELBASE), },
+		{ .xKernelEsid = GET_ESID(PAGE_OFFSET),
+		  .xKernelVsid = KERNEL_VSID(PAGE_OFFSET), },
 		{ .xKernelEsid = GET_ESID(VMALLOCBASE),
 		  .xKernelVsid = KERNEL_VSID(VMALLOCBASE), },
 	},
@@ -25,7 +25,7 @@ const struct LparMap __attribute__((__section__(".text"))) xLparMap = {
 	.xRanges = {
 		{ .xPages = HvPagesToMap,
 		  .xOffset = 0,
-		  .xVPN = KERNEL_VSID(KERNELBASE) << (SID_SHIFT - HW_PAGE_SHIFT),
+		  .xVPN = KERNEL_VSID(PAGE_OFFSET) << (SID_SHIFT - HW_PAGE_SHIFT),
 		},
 	},
 };