target/arm: Split helper_msr_i_pstate into 3

The EL0+UMA check is unique to DAIF.  While SPSel had avoided the
check by nature of already checking EL >= 1, the other post v8.0
extensions to MSR (imm) allow EL0 and do not require UMA.  Avoid
the unconditional write to pc and use raise_exception_ra to unwind.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20190301200501.16533-5-richard.henderson@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 30 insertions, 0 deletions

diff --git a/target/arm/helper-a64.c b/target/arm/helper-a64.c
index 70850e564d..796ef34b55 100644
--- a/target/arm/helper-a64.c
+++ b/target/arm/helper-a64.c
@@ -61,6 +61,36 @@ uint64_t HELPER(rbit64)(uint64_t x)
     return revbit64(x);
 }
 
+void HELPER(msr_i_spsel)(CPUARMState *env, uint32_t imm)
+{
+    update_spsel(env, imm);
+}
+
+static void daif_check(CPUARMState *env, uint32_t op,
+                       uint32_t imm, uintptr_t ra)
+{
+    /* DAIF update to PSTATE. This is OK from EL0 only if UMA is set.  */
+    if (arm_current_el(env) == 0 && !(env->cp15.sctlr_el[1] & SCTLR_UMA)) {
+        raise_exception_ra(env, EXCP_UDEF,
+                           syn_aa64_sysregtrap(0, extract32(op, 0, 3),
+                                               extract32(op, 3, 3), 4,
+                                               imm, 0x1f, 0),
+                           exception_target_el(env), ra);
+    }
+}
+
+void HELPER(msr_i_daifset)(CPUARMState *env, uint32_t imm)
+{
+    daif_check(env, 0x1e, imm, GETPC());
+    env->daif |= (imm << 6) & PSTATE_DAIF;
+}
+
+void HELPER(msr_i_daifclear)(CPUARMState *env, uint32_t imm)
+{
+    daif_check(env, 0x1f, imm, GETPC());
+    env->daif &= ~((imm << 6) & PSTATE_DAIF);
+}
+
 /* Convert a softfloat float_relation_ (as returned by
  * the float*_compare functions) to the correct ARM
  * NZCV flag state.