[Qemu-devel] [PULL 03/13] target-arm: Avoid calling arm_el_is_aa64() function for unimplemented EL

[Peter Maydell <peter.maydell@linaro.org>]

From: Sergey Sorokin <afarallax@yandex.ru>

It is incorrect to call arm_el_is_aa64() function for unimplemented EL.
This patch fixes several attempts to do so.

Signed-off-by: Sergey Sorokin <afarallax@yandex.ru>
[PMM: Reworked several of the comments to be more verbose.]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target-arm/cpu.h    | 11 ++++++++---
 target-arm/helper.c | 15 +++++++++++++--
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/target-arm/cpu.h b/target-arm/cpu.h
index 493f9d0..5fb0479 100644
--- a/target-arm/cpu.h
+++ b/target-arm/cpu.h
@@ -1016,11 +1016,11 @@ static inline bool access_secure_reg(CPUARMState *env)
  */
 #define A32_BANKED_CURRENT_REG_GET(_env, _regname)        \
     A32_BANKED_REG_GET((_env), _regname,                \
-                       ((!arm_el_is_aa64((_env), 3) && arm_is_secure(_env))))
+                       (arm_is_secure(_env) && !arm_el_is_aa64((_env), 3)))
 
 #define A32_BANKED_CURRENT_REG_SET(_env, _regname, _val)                       \
     A32_BANKED_REG_SET((_env), _regname,                                    \
-                       ((!arm_el_is_aa64((_env), 3) && arm_is_secure(_env))),  \
+                       (arm_is_secure(_env) && !arm_el_is_aa64((_env), 3)), \
                        (_val))
 
 void arm_cpu_list(FILE *f, fprintf_function cpu_fprintf);
@@ -1587,7 +1587,12 @@ static inline bool arm_excp_unmasked(CPUState *cs, unsigned int excp_idx,
      * interrupt.
      */
     if ((target_el > cur_el) && (target_el != 1)) {
-        if (arm_el_is_aa64(env, 3) || ((scr || hcr) && (!secure))) {
+        /* ARM_FEATURE_AARCH64 enabled means the highest EL is AArch64.
+         * This code currently assumes that EL2 is not implemented
+         * (and so that highest EL will be 3 and the target_el also 3).
+         */
+        if (arm_feature(env, ARM_FEATURE_AARCH64) ||
+            ((scr || hcr) && (!secure))) {
             unmasked = 1;
         }
     }
diff --git a/target-arm/helper.c b/target-arm/helper.c
index b498670..b2d78b0 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -5224,11 +5224,22 @@ uint32_t arm_phys_excp_target_el(CPUState *cs, uint32_t excp_idx,
                                  uint32_t cur_el, bool secure)
 {
     CPUARMState *env = cs->env_ptr;
-    int rw = ((env->cp15.scr_el3 & SCR_RW) == SCR_RW);
+    int rw;
     int scr;
     int hcr;
     int target_el;
-    int is64 = arm_el_is_aa64(env, 3);
+    /* Is the highest EL AArch64? */
+    int is64 = arm_feature(env, ARM_FEATURE_AARCH64);
+
+    if (arm_feature(env, ARM_FEATURE_EL3)) {
+        rw = ((env->cp15.scr_el3 & SCR_RW) == SCR_RW);
+    } else {
+        /* Either EL2 is the highest EL (and so the EL2 register width
+         * is given by is64); or there is no EL2 or EL3, in which case
+         * the value of 'rw' does not affect the table lookup anyway.
+         */
+        rw = is64;
+    }
 
     switch (excp_idx) {
     case EXCP_IRQ:
-- 
1.9.1