target/arm: Introduce arm_hcr_el2_eff

Replace arm_hcr_el2_{fmo,imo,amo} with a more general routine
that also takes SCR_EL3.NS (aka arm_is_secure_below_el3) into
account, as documented for the plethora of bits in HCR_EL2.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20181210150501.7990-2-richard.henderson@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

2 files changed, 72 insertions, 61 deletions

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 11ec2cc..05ac883 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -1729,6 +1729,14 @@ static inline bool arm_is_secure(CPUARMState *env)
 }
 #endif
 
+/**
+ * arm_hcr_el2_eff(): Return the effective value of HCR_EL2.
+ * E.g. when in secure state, fields in HCR_EL2 are suppressed,
+ * "for all purposes other than a direct read or write access of HCR_EL2."
+ * Not included here is HCR_RW.
+ */
+uint64_t arm_hcr_el2_eff(CPUARMState *env);
+
 /* Return true if the specified exception level is running in AArch64 state. */
 static inline bool arm_el_is_aa64(CPUARMState *env, int el)
 {
@@ -2414,54 +2422,6 @@ bool write_cpustate_to_list(ARMCPU *cpu);
 #  define TARGET_VIRT_ADDR_SPACE_BITS 32
 #endif
 
-/**
- * arm_hcr_el2_imo(): Return the effective value of HCR_EL2.IMO.
- * Depending on the values of HCR_EL2.E2H and TGE, this may be
- * "behaves as 1 for all purposes other than direct read/write" or
- * "behaves as 0 for all purposes other than direct read/write"
- */
-static inline bool arm_hcr_el2_imo(CPUARMState *env)
-{
-    switch (env->cp15.hcr_el2 & (HCR_TGE | HCR_E2H)) {
-    case HCR_TGE:
-        return true;
-    case HCR_TGE | HCR_E2H:
-        return false;
-    default:
-        return env->cp15.hcr_el2 & HCR_IMO;
-    }
-}
-
-/**
- * arm_hcr_el2_fmo(): Return the effective value of HCR_EL2.FMO.
- */
-static inline bool arm_hcr_el2_fmo(CPUARMState *env)
-{
-    switch (env->cp15.hcr_el2 & (HCR_TGE | HCR_E2H)) {
-    case HCR_TGE:
-        return true;
-    case HCR_TGE | HCR_E2H:
-        return false;
-    default:
-        return env->cp15.hcr_el2 & HCR_FMO;
-    }
-}
-
-/**
- * arm_hcr_el2_amo(): Return the effective value of HCR_EL2.AMO.
- */
-static inline bool arm_hcr_el2_amo(CPUARMState *env)
-{
-    switch (env->cp15.hcr_el2 & (HCR_TGE | HCR_E2H)) {
-    case HCR_TGE:
-        return true;
-    case HCR_TGE | HCR_E2H:
-        return false;
-    default:
-        return env->cp15.hcr_el2 & HCR_AMO;
-    }
-}
-
 static inline bool arm_excp_unmasked(CPUState *cs, unsigned int excp_idx,
                                      unsigned int target_el)
 {
@@ -2470,6 +2430,7 @@ static inline bool arm_excp_unmasked(CPUState *cs, unsigned int excp_idx,
     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
@@ -2479,6 +2440,8 @@ static inline bool arm_excp_unmasked(CPUState *cs, unsigned int excp_idx,
         return false;
     }
 
+    hcr_el2 = arm_hcr_el2_eff(env);
+
     switch (excp_idx) {
     case EXCP_FIQ:
         pstate_unmasked = !(env->daif & PSTATE_F);
@@ -2489,13 +2452,13 @@ static inline bool arm_excp_unmasked(CPUState *cs, unsigned int excp_idx,
         break;
 
     case EXCP_VFIQ:
-        if (secure || !arm_hcr_el2_fmo(env) || (env->cp15.hcr_el2 & HCR_TGE)) {
+        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 || !arm_hcr_el2_imo(env) || (env->cp15.hcr_el2 & HCR_TGE)) {
+        if (secure || !(hcr_el2 & HCR_IMO) || (hcr_el2 & HCR_TGE)) {
             /* VIRQs are only taken when hypervized and non-secure.  */
             return false;
         }
@@ -2534,7 +2497,7 @@ static inline bool arm_excp_unmasked(CPUState *cs, unsigned int excp_idx,
                  * to the CPSR.F setting otherwise we further assess the state
                  * below.
                  */
-                hcr = arm_hcr_el2_fmo(env);
+                hcr = hcr_el2 & HCR_FMO;
                 scr = (env->cp15.scr_el3 & SCR_FIQ);
 
                 /* When EL3 is 32-bit, the SCR.FW bit controls whether the
@@ -2551,7 +2514,7 @@ static inline bool arm_excp_unmasked(CPUState *cs, unsigned int excp_idx,
                  * when setting the target EL, so it does not have a further
                  * affect here.
                  */
-                hcr = arm_hcr_el2_imo(env);
+                hcr = hcr_el2 & HCR_IMO;
                 scr = false;
                 break;
             default:
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 037cece..95d59e0 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -1331,9 +1331,10 @@ static void csselr_write(CPUARMState *env, const ARMCPRegInfo *ri,
 static uint64_t isr_read(CPUARMState *env, const ARMCPRegInfo *ri)
 {
     CPUState *cs = ENV_GET_CPU(env);
+    uint64_t hcr_el2 = arm_hcr_el2_eff(env);
     uint64_t ret = 0;
 
-    if (arm_hcr_el2_imo(env)) {
+    if (hcr_el2 & HCR_IMO) {
         if (cs->interrupt_request & CPU_INTERRUPT_VIRQ) {
             ret |= CPSR_I;
         }
@@ -1343,7 +1344,7 @@ static uint64_t isr_read(CPUARMState *env, const ARMCPRegInfo *ri)
         }
     }
 
-    if (arm_hcr_el2_fmo(env)) {
+    if (hcr_el2 & HCR_FMO) {
         if (cs->interrupt_request & CPU_INTERRUPT_VFIQ) {
             ret |= CPSR_F;
         }
@@ -4008,6 +4009,51 @@ static void hcr_writelow(CPUARMState *env, const ARMCPRegInfo *ri,
     hcr_write(env, NULL, value);
 }
 
+/*
+ * Return the effective value of HCR_EL2.
+ * Bits that are not included here:
+ * RW       (read from SCR_EL3.RW as needed)
+ */
+uint64_t arm_hcr_el2_eff(CPUARMState *env)
+{
+    uint64_t ret = env->cp15.hcr_el2;
+
+    if (arm_is_secure_below_el3(env)) {
+        /*
+         * "This register has no effect if EL2 is not enabled in the
+         * current Security state".  This is ARMv8.4-SecEL2 speak for
+         * !(SCR_EL3.NS==1 || SCR_EL3.EEL2==1).
+         *
+         * Prior to that, the language was "In an implementation that
+         * includes EL3, when the value of SCR_EL3.NS is 0 the PE behaves
+         * as if this field is 0 for all purposes other than a direct
+         * read or write access of HCR_EL2".  With lots of enumeration
+         * on a per-field basis.  In current QEMU, this is condition
+         * is arm_is_secure_below_el3.
+         *
+         * Since the v8.4 language applies to the entire register, and
+         * appears to be backward compatible, use that.
+         */
+        ret = 0;
+    } else if (ret & HCR_TGE) {
+        /* These bits are up-to-date as of ARMv8.4.  */
+        if (ret & HCR_E2H) {
+            ret &= ~(HCR_VM | HCR_FMO | HCR_IMO | HCR_AMO |
+                     HCR_BSU_MASK | HCR_DC | HCR_TWI | HCR_TWE |
+                     HCR_TID0 | HCR_TID2 | HCR_TPCP | HCR_TPU |
+                     HCR_TDZ | HCR_CD | HCR_ID | HCR_MIOCNCE);
+        } else {
+            ret |= HCR_FMO | HCR_IMO | HCR_AMO;
+        }
+        ret &= ~(HCR_SWIO | HCR_PTW | HCR_VF | HCR_VI | HCR_VSE |
+                 HCR_FB | HCR_TID1 | HCR_TID3 | HCR_TSC | HCR_TACR |
+                 HCR_TSW | HCR_TTLB | HCR_TVM | HCR_HCD | HCR_TRVM |
+                 HCR_TLOR);
+    }
+
+    return ret;
+}
+
 static const ARMCPRegInfo el2_cp_reginfo[] = {
     { .name = "HCR_EL2", .state = ARM_CP_STATE_AA64,
       .type = ARM_CP_IO,
@@ -6526,12 +6572,13 @@ 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;
-    int scr;
-    int hcr;
+    bool rw;
+    bool scr;
+    bool hcr;
     int target_el;
     /* Is the highest EL AArch64? */
-    int is64 = arm_feature(env, ARM_FEATURE_AARCH64);
+    bool is64 = arm_feature(env, ARM_FEATURE_AARCH64);
+    uint64_t hcr_el2;
 
     if (arm_feature(env, ARM_FEATURE_EL3)) {
         rw = ((env->cp15.scr_el3 & SCR_RW) == SCR_RW);
@@ -6543,18 +6590,19 @@ uint32_t arm_phys_excp_target_el(CPUState *cs, uint32_t excp_idx,
         rw = is64;
     }
 
+    hcr_el2 = arm_hcr_el2_eff(env);
     switch (excp_idx) {
     case EXCP_IRQ:
         scr = ((env->cp15.scr_el3 & SCR_IRQ) == SCR_IRQ);
-        hcr = arm_hcr_el2_imo(env);
+        hcr = hcr_el2 & HCR_IMO;
         break;
     case EXCP_FIQ:
         scr = ((env->cp15.scr_el3 & SCR_FIQ) == SCR_FIQ);
-        hcr = arm_hcr_el2_fmo(env);
+        hcr = hcr_el2 & HCR_FMO;
         break;
     default:
         scr = ((env->cp15.scr_el3 & SCR_EA) == SCR_EA);
-        hcr = arm_hcr_el2_amo(env);
+        hcr = hcr_el2 & HCR_AMO;
         break;
     };