[PATCH v4 0/2] powerpc32: handle inverted _PAGE_RW bit outside of TLB handlers

[Christophe Leroy]

Some powerpc like the 8xx don't have a RW bit in PTE bits but a RO (Read Only) bit.
This patch implements the handling of a _PAGE_RO flag to be used in place of _PAGE_RW

Patchset:
1) powerpc32: adds handling of _PAGE_RO
2) powerpc/8xx: use _PAGE_RO instead of _PAGE_RW

All changes have been successfully tested on MPC885

Signed-off-by: Christophe Leroy <christophe.leroy at c-s.fr>
Tested-by: Christophe Leroy <christophe.leroy at c-s.fr>

---
v2 is a complete rework compared to v1
v3 takes into account comments from Scott on v2
v4 simplified pte_update()

 arch/powerpc/include/asm/pgtable-ppc32.h | 12 +++++++-----
 arch/powerpc/include/asm/pgtable.h       |  7 +++++--
 arch/powerpc/include/asm/pte-8xx.h       |  9 ++++-----
 arch/powerpc/include/asm/pte-common.h    | 25 +++++++++++++++++--------
 arch/powerpc/kernel/head_8xx.S           |  3 ---
 arch/powerpc/mm/gup.c                    |  2 ++
 arch/powerpc/mm/pgtable_32.c             |  2 +-
 7 files changed, 36 insertions(+), 24 deletions(-)