[Qemu-devel] [PATCH v2 0/4] target-arm: Clean up trap/undef handling of SRS

[Peter Maydell]

The SRS instruction is a bit of an oddity because it isn't
used by Linux these days. Nonetheless it has a bunch of
UNPREDICTABLE, UNDEF and trapping behaviour that we weren't
correctly implementing:

 - trap to EL3 if EL3 is AArch64 and we are at Secure EL1
 - UNDEFINED in Hyp mode
 - UNPREDICTABLE in User or System mode
 - UNPREDICTABLE if the specified mode is:
 -- not implemented
 -- not a valid mode number
 -- a mode that's at a higher exception level
 -- Monitor, if we are Non-secure

This series implements the checks we were missing and makes
us UNDEF for all the UNPREDICTABLE cases.

Patch 1 does the easy checks that can be done at translate time;
patches 2 and 3 are code motion in preparation for patch 4, which
puts in a run-time check for the one awkward case we don't have
enough information to UNDEF at translate time.

Changes v1->v2: drop the user-mode-only assertions from the
get_/set_r13_banked() functions as suggested in review.

These have all now been reviewed so I'm just sending them out
to the list for completeness -- I'll put the patches in
target-arm.next in a moment.


thanks
-- PMM


Peter Maydell (4):
  target-arm: Clean up trap/undef handling of SRS
  target-arm: Move get/set_r13_banked() to op_helper.c
  target-arm: Combine user-only and softmmu get/set_r13_banked()
  target-arm: UNDEF in the UNPREDICTABLE SRS-from-System case

 target-arm/helper.c    | 33 -------------------------
 target-arm/op_helper.c | 26 ++++++++++++++++++++
 target-arm/translate.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++----
 3 files changed, 88 insertions(+), 38 deletions(-)

-- 
1.9.1