target-arm: Make Monitor->NS PL1 mode changes illegal if HCR.TGE is 1
If HCR.TGE is 1 then mode changes via CPS and MSR from Monitor to
NonSecure PL1 modes are illegal mode changes. Implement this check
in bad_mode_switch().
(We don't currently implement HCR.TGE, but this is the only missing
check from the v8 ARM ARM G1.9.3 and so it's worth adding now; the
rest of the HCR.TGE checks can be added later as necessary.)
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Sergey Fedorov <serge.fdrv@gmail.com>
Message-id: 1455556977-3644-12-git-send-email-peter.maydell@linaro.org
diff --git a/target-arm/helper.c b/target-arm/helper.c
index 24ea48e..3d7fda1 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -5216,6 +5216,7 @@
switch (mode) {
case ARM_CPU_MODE_USR:
+ return 0;
case ARM_CPU_MODE_SYS:
case ARM_CPU_MODE_SVC:
case ARM_CPU_MODE_ABT:
@@ -5225,6 +5226,15 @@
/* Note that we don't implement the IMPDEF NSACR.RFR which in v7
* allows FIQ mode to be Secure-only. (In v8 this doesn't exist.)
*/
+ /* If HCR.TGE is set then changes from Monitor to NS PL1 via MSR
+ * and CPS are treated as illegal mode changes.
+ */
+ if (write_type == CPSRWriteByInstr &&
+ (env->cp15.hcr_el2 & HCR_TGE) &&
+ (env->uncached_cpsr & CPSR_M) == ARM_CPU_MODE_MON &&
+ !arm_is_secure_below_el3(env)) {
+ return 1;
+ }
return 0;
case ARM_CPU_MODE_HYP:
return !arm_feature(env, ARM_FEATURE_EL2)
