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-rw-r--r--target/arm/tcg/op_helper.c43
-rw-r--r--target/arm/tcg/translate.c19
2 files changed, 43 insertions, 19 deletions
diff --git a/target/arm/tcg/op_helper.c b/target/arm/tcg/op_helper.c
index b5ac26061c..c199b69fbf 100644
--- a/target/arm/tcg/op_helper.c
+++ b/target/arm/tcg/op_helper.c
@@ -570,10 +570,24 @@ static void msr_mrs_banked_exc_checks(CPUARMState *env, uint32_t tgtmode,
      */
     int curmode = env->uncached_cpsr & CPSR_M;
 
-    if (regno == 17) {
-        /* ELR_Hyp: a special case because access from tgtmode is OK */
-        if (curmode != ARM_CPU_MODE_HYP && curmode != ARM_CPU_MODE_MON) {
-            goto undef;
+    if (tgtmode == ARM_CPU_MODE_HYP) {
+        /*
+         * Handle Hyp target regs first because some are special cases
+         * which don't want the usual "not accessible from tgtmode" check.
+         */
+        switch (regno) {
+        case 16 ... 17: /* ELR_Hyp, SPSR_Hyp */
+            if (curmode != ARM_CPU_MODE_HYP && curmode != ARM_CPU_MODE_MON) {
+                goto undef;
+            }
+            break;
+        case 13:
+            if (curmode != ARM_CPU_MODE_MON) {
+                goto undef;
+            }
+            break;
+        default:
+            g_assert_not_reached();
         }
         return;
     }
@@ -604,13 +618,6 @@ static void msr_mrs_banked_exc_checks(CPUARMState *env, uint32_t tgtmode,
         }
     }
 
-    if (tgtmode == ARM_CPU_MODE_HYP) {
-        /* SPSR_Hyp, r13_hyp: accessible from Monitor mode only */
-        if (curmode != ARM_CPU_MODE_MON) {
-            goto undef;
-        }
-    }
-
     return;
 
 undef:
@@ -625,7 +632,12 @@ void HELPER(msr_banked)(CPUARMState *env, uint32_t value, uint32_t tgtmode,
 
     switch (regno) {
     case 16: /* SPSRs */
-        env->banked_spsr[bank_number(tgtmode)] = value;
+        if (tgtmode == (env->uncached_cpsr & CPSR_M)) {
+            /* Only happens for SPSR_Hyp access in Hyp mode */
+            env->spsr = value;
+        } else {
+            env->banked_spsr[bank_number(tgtmode)] = value;
+        }
         break;
     case 17: /* ELR_Hyp */
         env->elr_el[2] = value;
@@ -659,7 +671,12 @@ uint32_t HELPER(mrs_banked)(CPUARMState *env, uint32_t tgtmode, uint32_t regno)
 
     switch (regno) {
     case 16: /* SPSRs */
-        return env->banked_spsr[bank_number(tgtmode)];
+        if (tgtmode == (env->uncached_cpsr & CPSR_M)) {
+            /* Only happens for SPSR_Hyp access in Hyp mode */
+            return env->spsr;
+        } else {
+            return env->banked_spsr[bank_number(tgtmode)];
+        }
     case 17: /* ELR_Hyp */
         return env->elr_el[2];
     case 13:
diff --git a/target/arm/tcg/translate.c b/target/arm/tcg/translate.c
index 5fa8249723..f947c62c6b 100644
--- a/target/arm/tcg/translate.c
+++ b/target/arm/tcg/translate.c
@@ -2822,13 +2822,20 @@ static bool msr_banked_access_decode(DisasContext *s, int r, int sysm, int rn,
         break;
     case ARM_CPU_MODE_HYP:
         /*
-         * SPSR_hyp and r13_hyp can only be accessed from Monitor mode
-         * (and so we can forbid accesses from EL2 or below). elr_hyp
-         * can be accessed also from Hyp mode, so forbid accesses from
-         * EL0 or EL1.
+         * r13_hyp can only be accessed from Monitor mode, and so we
+         * can forbid accesses from EL2 or below.
+         * elr_hyp can be accessed also from Hyp mode, so forbid
+         * accesses from EL0 or EL1.
+         * SPSR_hyp is supposed to be in the same category as r13_hyp
+         * and UNPREDICTABLE if accessed from anything except Monitor
+         * mode. However there is some real-world code that will do
+         * it because at least some hardware happens to permit the
+         * access. (Notably a standard Cortex-R52 startup code fragment
+         * does this.) So we permit SPSR_hyp from Hyp mode also, to allow
+         * this (incorrect) guest code to run.
          */
-        if (!arm_dc_feature(s, ARM_FEATURE_EL2) || s->current_el < 2 ||
-            (s->current_el < 3 && *regno != 17)) {
+        if (!arm_dc_feature(s, ARM_FEATURE_EL2) || s->current_el < 2
+            || (s->current_el < 3 && *regno != 16 && *regno != 17)) {
             goto undef;
         }
         break;