target/arm: Move arm_excp_unmasked to cpu.c

This inline function has one user in cpu.c, and need not be exposed
otherwise.  Code movement only, with fixups for checkpatch.

Tested-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200206105448.4726-39-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 119 insertions, 0 deletions

diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index 1ecf2adb6a..b81ed44bd2 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -410,6 +410,125 @@ static void arm_cpu_reset(CPUState *s)
     arm_rebuild_hflags(env);
 }
 
+static inline bool arm_excp_unmasked(CPUState *cs, unsigned int excp_idx,
+                                     unsigned int target_el)
+{
+    CPUARMState *env = cs->env_ptr;
+    unsigned int cur_el = arm_current_el(env);
+    bool secure = arm_is_secure(env);
+    bool pstate_unmasked;
+    int8_t unmasked = 0;
+    uint64_t hcr_el2;
+
+    /*
+     * Don't take exceptions if they target a lower EL.
+     * This check should catch any exceptions that would not be taken
+     * but left pending.
+     */
+    if (cur_el > target_el) {
+        return false;
+    }
+
+    hcr_el2 = arm_hcr_el2_eff(env);
+
+    switch (excp_idx) {
+    case EXCP_FIQ:
+        pstate_unmasked = !(env->daif & PSTATE_F);
+        break;
+
+    case EXCP_IRQ:
+        pstate_unmasked = !(env->daif & PSTATE_I);
+        break;
+
+    case EXCP_VFIQ:
+        if (secure || !(hcr_el2 & HCR_FMO) || (hcr_el2 & HCR_TGE)) {
+            /* VFIQs are only taken when hypervized and non-secure.  */
+            return false;
+        }
+        return !(env->daif & PSTATE_F);
+    case EXCP_VIRQ:
+        if (secure || !(hcr_el2 & HCR_IMO) || (hcr_el2 & HCR_TGE)) {
+            /* VIRQs are only taken when hypervized and non-secure.  */
+            return false;
+        }
+        return !(env->daif & PSTATE_I);
+    default:
+        g_assert_not_reached();
+    }
+
+    /*
+     * Use the target EL, current execution state and SCR/HCR settings to
+     * determine whether the corresponding CPSR bit is used to mask the
+     * interrupt.
+     */
+    if ((target_el > cur_el) && (target_el != 1)) {
+        /* Exceptions targeting a higher EL may not be maskable */
+        if (arm_feature(env, ARM_FEATURE_AARCH64)) {
+            /*
+             * 64-bit masking rules are simple: exceptions to EL3
+             * can't be masked, and exceptions to EL2 can only be
+             * masked from Secure state. The HCR and SCR settings
+             * don't affect the masking logic, only the interrupt routing.
+             */
+            if (target_el == 3 || !secure) {
+                unmasked = 1;
+            }
+        } else {
+            /*
+             * The old 32-bit-only environment has a more complicated
+             * masking setup. HCR and SCR bits not only affect interrupt
+             * routing but also change the behaviour of masking.
+             */
+            bool hcr, scr;
+
+            switch (excp_idx) {
+            case EXCP_FIQ:
+                /*
+                 * If FIQs are routed to EL3 or EL2 then there are cases where
+                 * we override the CPSR.F in determining if the exception is
+                 * masked or not. If neither of these are set then we fall back
+                 * to the CPSR.F setting otherwise we further assess the state
+                 * below.
+                 */
+                hcr = hcr_el2 & HCR_FMO;
+                scr = (env->cp15.scr_el3 & SCR_FIQ);
+
+                /*
+                 * When EL3 is 32-bit, the SCR.FW bit controls whether the
+                 * CPSR.F bit masks FIQ interrupts when taken in non-secure
+                 * state. If SCR.FW is set then FIQs can be masked by CPSR.F
+                 * when non-secure but only when FIQs are only routed to EL3.
+                 */
+                scr = scr && !((env->cp15.scr_el3 & SCR_FW) && !hcr);
+                break;
+            case EXCP_IRQ:
+                /*
+                 * When EL3 execution state is 32-bit, if HCR.IMO is set then
+                 * we may override the CPSR.I masking when in non-secure state.
+                 * The SCR.IRQ setting has already been taken into consideration
+                 * when setting the target EL, so it does not have a further
+                 * affect here.
+                 */
+                hcr = hcr_el2 & HCR_IMO;
+                scr = false;
+                break;
+            default:
+                g_assert_not_reached();
+            }
+
+            if ((scr || hcr) && !secure) {
+                unmasked = 1;
+            }
+        }
+    }
+
+    /*
+     * The PSTATE bits only mask the interrupt if we have not overriden the
+     * ability above.
+     */
+    return unmasked || pstate_unmasked;
+}
+
 bool arm_cpu_exec_interrupt(CPUState *cs, int interrupt_request)
 {
     CPUClass *cc = CPU_GET_CLASS(cs);