[PATCH 04/18] target/arm: Move HCR_TGE check into exception_target_el

[Richard Henderson <richard.henderson@linaro.org>]

Move the TGE test from raise_exception into
exception_target_el to consolidate tests in one place.
Note that this ought to apply only to origin of EL0,
but that cannot be confirmed at this time.
Update the AdvSIMDFPAccessTrap doc reference to DDI0478H.a.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/op_helper.c | 47 +++++++++++++++++++++++++-----------------
 1 file changed, 28 insertions(+), 19 deletions(-)

diff --git a/target/arm/op_helper.c b/target/arm/op_helper.c
index 6858b8980d..55440dfa84 100644
--- a/target/arm/op_helper.c
+++ b/target/arm/op_helper.c
@@ -30,17 +30,39 @@
 
 int exception_target_el(CPUARMState *env, int cur_el, uint32_t *psyn)
 {
-    int target_el = MAX(1, cur_el);
+    /*
+     * FIXME: The following tests really apply to an EL0 origin,
+     * not to a target of EL1.  However, the origin will never be
+     * EL1 for these cases (no aa32 secure EL1, can't enter EL1
+     * with TGE set).  Delay fixing this until all places that
+     * might perform MAX(cur_el, 1) are audited.
+     */
+    if (cur_el >= 2) {
+        return 2;
+    }
 
     /*
      * No such thing as secure EL1 if EL3 is aarch32,
      * so update the target EL to EL3 in this case.
      */
-    if (arm_is_secure(env) && !arm_el_is_aa64(env, 3) && target_el == 1) {
-        target_el = 3;
+    if (arm_is_secure(env) && !arm_el_is_aa64(env, 3)) {
+        return 3;
     }
 
-    return target_el;
+    if (arm_hcr_el2_eff(env) & HCR_TGE) {
+        /*
+         * Redirect NS EL1 exceptions to NS EL2. These are reported with
+         * their original syndrome register value, with the exception of
+         * SIMD/FP access traps, which are reported as uncategorized
+         * (see DDI0487 H.a rule RJNBTN).
+         */
+        if (psyn && syn_get_ec(*psyn) == EC_ADVSIMDFPACCESSTRAP) {
+            *psyn = syn_uncategorized();
+        }
+        return 2;
+    }
+
+    return 1;
 }
 
 void raise_exception(CPUARMState *env, uint32_t excp, uint32_t syndrome,
@@ -49,21 +71,8 @@ void raise_exception(CPUARMState *env, uint32_t excp, uint32_t syndrome,
     CPUState *cs = env_cpu(env);
     int target_el = cur_or_target_el;
 
-    if (cur_or_target_el == 0) {
-        target_el = exception_target_el(env, 0, &syndrome);
-    }
-
-    if (target_el == 1 && (arm_hcr_el2_eff(env) & HCR_TGE)) {
-        /*
-         * Redirect NS EL1 exceptions to NS EL2. These are reported with
-         * their original syndrome register value, with the exception of
-         * SIMD/FP access traps, which are reported as uncategorized
-         * (see DDI0478C.a D1.10.4)
-         */
-        target_el = 2;
-        if (syn_get_ec(syndrome) == EC_ADVSIMDFPACCESSTRAP) {
-            syndrome = syn_uncategorized();
-        }
+    if (cur_or_target_el <= 1) {
+        target_el = exception_target_el(env, cur_or_target_el, &syndrome);
     }
 
     assert(!excp_is_internal(excp));
-- 
2.34.1