[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/mm/slb.c b/arch/powerpc/mm/slb.c
index a47b273600ec..cc22570856af 100644
--- a/arch/powerpc/mm/slb.c
+++ b/arch/powerpc/mm/slb.c
@@ -75,7 +75,7 @@ static void slb_flush_and_rebolt(void)
         vflags = SLB_VSID_KERNEL | virtual_llp;
 
         ksp_esid_data = mk_esid_data(get_paca()->kstack, 2);
-        if ((ksp_esid_data & ESID_MASK) == KERNELBASE)
+        if ((ksp_esid_data & ESID_MASK) == PAGE_OFFSET)
                 ksp_esid_data &= ~SLB_ESID_V;
 
         /* We need to do this all in asm, so we're sure we don't touch
@@ -213,7 +213,7 @@ void slb_initialize(void)
         asm volatile("isync":::"memory");
         asm volatile("slbmte  %0,%0"::"r" (0) : "memory");
         asm volatile("isync; slbia; isync":::"memory");
-        create_slbe(KERNELBASE, lflags, 0);
+        create_slbe(PAGE_OFFSET, lflags, 0);
 
         /* VMALLOC space has 4K pages always for now */
         create_slbe(VMALLOCBASE, vflags, 1);