target/arm: Split M profile MNegPri mmu index into user and priv

For M profile, we currently have an mmu index MNegPri for
"requested execution priority negative". This fails to
distinguish "requested execution priority negative, privileged"
from "requested execution priority negative, usermode", but
the two can return different results for MPU lookups. Fix this
by splitting MNegPri into MNegPriPriv and MNegPriUser, and
similarly for the Secure equivalent MSNegPri.

This takes us from 6 M profile MMU modes to 8, which means
we need to bump NB_MMU_MODES; this is OK since the point
where we are forced to reduce TLB sizes is 9 MMU modes.

(It would in theory be possible to stick with 6 MMU indexes:
{mpu-disabled,user,privileged} x {secure,nonsecure} since
in the MPU-disabled case the result of an MPU lookup is
always the same for both user and privileged code. However
we would then need to rework the TB flags handling to put
user/priv into the TB flags separately from the mmuidx.
Adding an extra couple of mmu indexes is simpler.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 1512153879-5291-5-git-send-email-peter.maydell@linaro.org

1 files changed, 6 insertions, 2 deletions

diff --git a/target/arm/translate.c b/target/arm/translate.c
index f120932f44..50339e7bdd 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -159,12 +159,16 @@ static inline int get_a32_user_mem_index(DisasContext *s)
         return arm_to_core_mmu_idx(ARMMMUIdx_S1SE0);
     case ARMMMUIdx_MUser:
     case ARMMMUIdx_MPriv:
-    case ARMMMUIdx_MNegPri:
         return arm_to_core_mmu_idx(ARMMMUIdx_MUser);
+    case ARMMMUIdx_MUserNegPri:
+    case ARMMMUIdx_MPrivNegPri:
+        return arm_to_core_mmu_idx(ARMMMUIdx_MUserNegPri);
     case ARMMMUIdx_MSUser:
     case ARMMMUIdx_MSPriv:
-    case ARMMMUIdx_MSNegPri:
         return arm_to_core_mmu_idx(ARMMMUIdx_MSUser);
+    case ARMMMUIdx_MSUserNegPri:
+    case ARMMMUIdx_MSPrivNegPri:
+        return arm_to_core_mmu_idx(ARMMMUIdx_MSUserNegPri);
     case ARMMMUIdx_S2NS:
     default:
         g_assert_not_reached();