powerpc: rework 4xx PTE access and TLB miss

This is some preliminary work to improve TLB management on SW loaded
TLB powerpc platforms. This introduce support for non-atomic PTE
operations in pgtable-ppc32.h and removes write back to the PTE from
the TLB miss handlers. In addition, the DSI interrupt code no longer
tries to fixup write permission, this is left to generic code, and
_PAGE_HWWRITE is gone.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/head_booke.h b/arch/powerpc/kernel/head_booke.h
index b0461be1c928..fce2df988504 100644
--- a/arch/powerpc/kernel/head_booke.h
+++ b/arch/powerpc/kernel/head_booke.h
@@ -340,6 +340,14 @@ label:
         addi    r3,r1,STACK_FRAME_OVERHEAD;                                   \
         EXC_XFER_TEMPLATE(DebugException, 0x2002, (MSR_KERNEL & ~(MSR_ME|MSR_DE|MSR_CE)), NOCOPY, crit_transfer_to_handler, ret_from_crit_exc)
 
+#define DATA_STORAGE_EXCEPTION                                                \
+        START_EXCEPTION(DataStorage)                                          \
+        NORMAL_EXCEPTION_PROLOG;                                              \
+        mfspr   r5,SPRN_ESR;            /* Grab the ESR and save it */        \
+        stw     r5,_ESR(r11);                                                 \
+        mfspr   r4,SPRN_DEAR;           /* Grab the DEAR */                   \
+        EXC_XFER_EE_LITE(0x0300, handle_page_fault)
+
 #define INSTRUCTION_STORAGE_EXCEPTION                                         \
         START_EXCEPTION(InstructionStorage)                                   \
         NORMAL_EXCEPTION_PROLOG;                                              \