[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, 5 insertions, 5 deletions

diff --git a/arch/powerpc/mm/stab.c b/arch/powerpc/mm/stab.c
index a18dab0d6b12..82e4951826bc 100644
--- a/arch/powerpc/mm/stab.c
+++ b/arch/powerpc/mm/stab.c
@@ -40,7 +40,7 @@ static int make_ste(unsigned long stab, unsigned long esid, unsigned long vsid)
         unsigned long entry, group, old_esid, castout_entry, i;
         unsigned int global_entry;
         struct stab_entry *ste, *castout_ste;
-        unsigned long kernel_segment = (esid << SID_SHIFT) >= KERNELBASE;
+        unsigned long kernel_segment = (esid << SID_SHIFT) >= PAGE_OFFSET;
 
         vsid_data = vsid << STE_VSID_SHIFT;
         esid_data = esid << SID_SHIFT | STE_ESID_KP | STE_ESID_V;
@@ -83,7 +83,7 @@ static int make_ste(unsigned long stab, unsigned long esid, unsigned long vsid)
                 }
 
                 /* Dont cast out the first kernel segment */
-                if ((castout_ste->esid_data & ESID_MASK) != KERNELBASE)
+                if ((castout_ste->esid_data & ESID_MASK) != PAGE_OFFSET)
                         break;
 
                 castout_entry = (castout_entry + 1) & 0xf;
@@ -251,7 +251,7 @@ void stabs_alloc(void)
                         panic("Unable to allocate segment table for CPU %d.\n",
                               cpu);
 
-                newstab += KERNELBASE;
+                newstab = (unsigned long)__va(newstab);
 
                 memset((void *)newstab, 0, HW_PAGE_SIZE);
 
@@ -270,11 +270,11 @@ void stabs_alloc(void)
  */
 void stab_initialize(unsigned long stab)
 {
-        unsigned long vsid = get_kernel_vsid(KERNELBASE);
+        unsigned long vsid = get_kernel_vsid(PAGE_OFFSET);
         unsigned long stabreal;
 
         asm volatile("isync; slbia; isync":::"memory");
-        make_ste(stab, GET_ESID(KERNELBASE), vsid);
+        make_ste(stab, GET_ESID(PAGE_OFFSET), vsid);
 
         /* Order update */
         asm volatile("sync":::"memory");