Revert "convert SLB miss handlers to C" and subsequent commits

This reverts commits:
  5e46e29e6a97 ("powerpc/64s/hash: convert SLB miss handlers to C")
  8fed04d0f6ae ("powerpc/64s/hash: remove user SLB data from the paca")
  655deecf67b2 ("powerpc/64s/hash: SLB allocation status bitmaps")
  2e1626744e8d ("powerpc/64s/hash: provide arch_setup_exec hooks for hash slice setup")
  89ca4e126a3f ("powerpc/64s/hash: Add a SLB preload cache")

This series had a few bugs, and the fixes are not all trivial. So
revert most of it for now.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 8 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h
index 47578b79f0fb..a86feddddad0 100644
--- a/arch/powerpc/include/asm/exception-64s.h
+++ b/arch/powerpc/include/asm/exception-64s.h
@@ -61,6 +61,14 @@
 #define MAX_MCE_DEPTH	4
 
 /*
+ * EX_LR is only used in EXSLB and where it does not overlap with EX_DAR
+ * EX_CCR similarly with DSISR, but being 4 byte registers there is a hole
+ * in the save area so it's not necessary to overlap them. Could be used
+ * for future savings though if another 4 byte register was to be saved.
+ */
+#define EX_LR		EX_DAR
+
+/*
  * EX_R3 is only used by the bad_stack handler. bad_stack reloads and
  * saves DAR from SPRN_DAR, and EX_DAR is not used. So EX_R3 can overlap
  * with EX_DAR.