target/arm: fix incorrect current EL bug in aarch32 exception emulation

The arm_current_el() should be invoked after mode switching. Otherwise, we
get a wrong current EL value, since current EL is also determined by
current mode.

Fixes: 4a2696c0d4 ("target/arm: Set PAN bit as required on exception entry")
Signed-off-by: Changbin Du <changbin.du@gmail.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200328140232.17278-1-changbin.du@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

diff --git a/target/arm/helper.c b/target/arm/helper.c
index b7b6887241dd4eef21cc922b4305404d459ec40f..163c91a1ccdde7914133cf9e93ce46d1daf3648b 100644 (file)
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -9172,7 +9172,6 @@ static void take_aarch32_exception(CPUARMState *env, int new_mode,
 
     /* Change the CPU state so as to actually take the exception. */
     switch_mode(env, new_mode);
-    new_el = arm_current_el(env);
 
     /*
      * For exceptions taken to AArch32 we must clear the SS bit in both
@@ -9184,6 +9183,10 @@ static void take_aarch32_exception(CPUARMState *env, int new_mode,
     env->condexec_bits = 0;
     /* Switch to the new mode, and to the correct instruction set.  */
     env->uncached_cpsr = (env->uncached_cpsr & ~CPSR_M) | new_mode;
+
+    /* This must be after mode switching. */
+    new_el = arm_current_el(env);
+
     /* Set new mode endianness */
     env->uncached_cpsr &= ~CPSR_E;
     if (env->cp15.sctlr_el[new_el] & SCTLR_EE) {