target/arm: Filter cycle counter based on PMCCFILTR_EL0

Rename arm_ccnt_enabled to pmu_counter_enabled, and add logic to only
return 'true' if the specified counter is enabled and neither prohibited
or filtered.

Signed-off-by: Aaron Lindsay <alindsay@codeaurora.org>
Signed-off-by: Aaron Lindsay <aclindsa@gmail.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20181211151945.29137-5-aaron@os.amperecomputing.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 89 insertions, 7 deletions

diff --git a/target/arm/helper.c b/target/arm/helper.c
index 733cfdc5a0..2535c7dba6 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -976,10 +976,24 @@ static const ARMCPRegInfo v6_cp_reginfo[] = {
 /* Definitions for the PMU registers */
 #define PMCRN_MASK  0xf800
 #define PMCRN_SHIFT 11
+#define PMCRDP  0x10
 #define PMCRD   0x8
 #define PMCRC   0x4
 #define PMCRE   0x1
 
+#define PMXEVTYPER_P          0x80000000
+#define PMXEVTYPER_U          0x40000000
+#define PMXEVTYPER_NSK        0x20000000
+#define PMXEVTYPER_NSU        0x10000000
+#define PMXEVTYPER_NSH        0x08000000
+#define PMXEVTYPER_M          0x04000000
+#define PMXEVTYPER_MT         0x02000000
+#define PMXEVTYPER_EVTCOUNT   0x0000ffff
+#define PMXEVTYPER_MASK       (PMXEVTYPER_P | PMXEVTYPER_U | PMXEVTYPER_NSK | \
+                               PMXEVTYPER_NSU | PMXEVTYPER_NSH | \
+                               PMXEVTYPER_M | PMXEVTYPER_MT | \
+                               PMXEVTYPER_EVTCOUNT)
+
 static inline uint32_t pmu_num_counters(CPUARMState *env)
 {
   return (env->cp15.c9_pmcr & PMCRN_MASK) >> PMCRN_SHIFT;
@@ -1075,16 +1089,66 @@ static CPAccessResult pmreg_access_ccntr(CPUARMState *env,
     return pmreg_access(env, ri, isread);
 }
 
-static inline bool arm_ccnt_enabled(CPUARMState *env)
+/* Returns true if the counter (pass 31 for PMCCNTR) should count events using
+ * the current EL, security state, and register configuration.
+ */
+static bool pmu_counter_enabled(CPUARMState *env, uint8_t counter)
 {
-    /* This does not support checking PMCCFILTR_EL0 register */
+    uint64_t filter;
+    bool e, p, u, nsk, nsu, nsh, m;
+    bool enabled, prohibited, filtered;
+    bool secure = arm_is_secure(env);
+    int el = arm_current_el(env);
+    uint8_t hpmn = env->cp15.mdcr_el2 & MDCR_HPMN;
 
-    if (!(env->cp15.c9_pmcr & PMCRE) || !(env->cp15.c9_pmcnten & (1 << 31))) {
-        return false;
+    if (!arm_feature(env, ARM_FEATURE_EL2) ||
+            (counter < hpmn || counter == 31)) {
+        e = env->cp15.c9_pmcr & PMCRE;
+    } else {
+        e = env->cp15.mdcr_el2 & MDCR_HPME;
     }
+    enabled = e && (env->cp15.c9_pmcnten & (1 << counter));
 
-    return true;
+    if (!secure) {
+        if (el == 2 && (counter < hpmn || counter == 31)) {
+            prohibited = env->cp15.mdcr_el2 & MDCR_HPMD;
+        } else {
+            prohibited = false;
+        }
+    } else {
+        prohibited = arm_feature(env, ARM_FEATURE_EL3) &&
+           (env->cp15.mdcr_el3 & MDCR_SPME);
+    }
+
+    if (prohibited && counter == 31) {
+        prohibited = env->cp15.c9_pmcr & PMCRDP;
+    }
+
+    /* TODO Remove assert, set filter to correct PMEVTYPER */
+    assert(counter == 31);
+    filter = env->cp15.pmccfiltr_el0;
+
+    p   = filter & PMXEVTYPER_P;
+    u   = filter & PMXEVTYPER_U;
+    nsk = arm_feature(env, ARM_FEATURE_EL3) && (filter & PMXEVTYPER_NSK);
+    nsu = arm_feature(env, ARM_FEATURE_EL3) && (filter & PMXEVTYPER_NSU);
+    nsh = arm_feature(env, ARM_FEATURE_EL2) && (filter & PMXEVTYPER_NSH);
+    m   = arm_el_is_aa64(env, 1) &&
+              arm_feature(env, ARM_FEATURE_EL3) && (filter & PMXEVTYPER_M);
+
+    if (el == 0) {
+        filtered = secure ? u : u != nsu;
+    } else if (el == 1) {
+        filtered = secure ? p : p != nsk;
+    } else if (el == 2) {
+        filtered = !nsh;
+    } else { /* EL3 */
+        filtered = m != p;
+    }
+
+    return enabled && !prohibited && !filtered;
 }
+
 /*
  * Ensure c15_ccnt is the guest-visible count so that operations such as
  * enabling/disabling the counter or filtering, modifying the count itself,
@@ -1097,7 +1161,7 @@ void pmccntr_op_start(CPUARMState *env)
     cycles = muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL),
                           ARM_CPU_FREQ, NANOSECONDS_PER_SECOND);
 
-    if (arm_ccnt_enabled(env)) {
+    if (pmu_counter_enabled(env, 31)) {
         uint64_t eff_cycles = cycles;
         if (env->cp15.c9_pmcr & PMCRD) {
             /* Increment once every 64 processor clock cycles */
@@ -1116,7 +1180,7 @@ void pmccntr_op_start(CPUARMState *env)
  */
 void pmccntr_op_finish(CPUARMState *env)
 {
-    if (arm_ccnt_enabled(env)) {
+    if (pmu_counter_enabled(env, 31)) {
         uint64_t prev_cycles = env->cp15.c15_ccnt_delta;
 
         if (env->cp15.c9_pmcr & PMCRD) {
@@ -1138,6 +1202,16 @@ void pmu_op_finish(CPUARMState *env)
     pmccntr_op_finish(env);
 }
 
+void pmu_pre_el_change(ARMCPU *cpu, void *ignored)
+{
+    pmu_op_start(&cpu->env);
+}
+
+void pmu_post_el_change(ARMCPU *cpu, void *ignored)
+{
+    pmu_op_finish(&cpu->env);
+}
+
 static void pmcr_write(CPUARMState *env, const ARMCPRegInfo *ri,
                        uint64_t value)
 {
@@ -1209,6 +1283,14 @@ void pmu_op_finish(CPUARMState *env)
 {
 }
 
+void pmu_pre_el_change(ARMCPU *cpu, void *ignored)
+{
+}
+
+void pmu_post_el_change(ARMCPU *cpu, void *ignored)
+{
+}
+
 #endif
 
 static void pmccfiltr_write(CPUARMState *env, const ARMCPRegInfo *ri,