powerpc/mm: Tweak PTE bit combination definitions

This patch tweaks the way some PTE bit combinations are defined, in such a
way that the 32 and 64-bit variant become almost identical and that will
make it easier to bring in a new common pte-* file for the new variant
of the Book3-E support.

The combination of bits defining access to kernel pages are now clearly
separated from the combination used by userspace and the core VM. The
resulting generated code should remain identical unless I made a mistake.

Note: While at it, I removed a non-sensical statement related to CONFIG_KGDB
in ppc_mmu_32.c which could cause kernel mappings to be user accessible when
that option is enabled. Probably something that bitrot.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
index 5c1c4880723c..81574f94ea32 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h
@@ -25,6 +25,10 @@ static inline void assert_pte_locked(struct mm_struct *mm, unsigned long addr)
 #  include <asm/pgtable-ppc32.h>
 #endif
 
+/* Special mapping for AGP */
+#define PAGE_AGP        (PAGE_KERNEL_NC)
+#define HAVE_PAGE_AGP
+
 #ifndef __ASSEMBLY__
 
 /* Insert a PTE, top-level function is out of line. It uses an inline