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authorPeter Maydell <peter.maydell@linaro.org>2022-08-22 14:23:56 +0100
committerRichard Henderson <richard.henderson@linaro.org>2022-09-14 11:19:40 +0100
commit0b42f4fab9d3e994efa44e17cb76c15b269bcbda (patch)
treeca700a981fda9bba6f7e671f2f71890e9f63eb53 /target/arm/helper.c
parenta793bcd0272d9d25c942184ee18c7ed4dc75dc0d (diff)
downloadfocaccia-qemu-0b42f4fab9d3e994efa44e17cb76c15b269bcbda.tar.gz
focaccia-qemu-0b42f4fab9d3e994efa44e17cb76c15b269bcbda.zip
target/arm: Implement FEAT_PMUv3p5 cycle counter disable bits
FEAT_PMUv3p5 introduces new bits which disable the cycle
counter from counting:
 * MDCR_EL2.HCCD disables the counter when in EL2
 * MDCR_EL3.SCCD disables the counter when Secure

Add the code to support these bits.

(Note that there is a third documented counter-disable
bit, MDCR_EL3.MCCD, which disables the counter when in
EL3. This is not present until FEAT_PMUv3p7, so is
out of scope for now.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220822132358.3524971-9-peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'target/arm/helper.c')
-rw-r--r--target/arm/helper.c21
1 files changed, 17 insertions, 4 deletions
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 987ac19fe8..0d1f23de09 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -1084,8 +1084,8 @@ static CPAccessResult pmreg_access_ccntr(CPUARMState *env,
  * We use these to decide whether we need to wrap a write to MDCR_EL2
  * or MDCR_EL3 in pmu_op_start()/pmu_op_finish() calls.
  */
-#define MDCR_EL2_PMU_ENABLE_BITS (MDCR_HPME | MDCR_HPMD | MDCR_HPMN)
-#define MDCR_EL3_PMU_ENABLE_BITS (MDCR_SPME)
+#define MDCR_EL2_PMU_ENABLE_BITS (MDCR_HPME | MDCR_HPMD | MDCR_HPMN | MDCR_HCCD)
+#define MDCR_EL3_PMU_ENABLE_BITS (MDCR_SPME | MDCR_SCCD)
 
 /* Returns true if the counter (pass 31 for PMCCNTR) should count events using
  * the current EL, security state, and register configuration.
@@ -1120,8 +1120,21 @@ static bool pmu_counter_enabled(CPUARMState *env, uint8_t counter)
         prohibited = prohibited || !(env->cp15.mdcr_el3 & MDCR_SPME);
     }
 
-    if (prohibited && counter == 31) {
-        prohibited = env->cp15.c9_pmcr & PMCRDP;
+    if (counter == 31) {
+        /*
+         * The cycle counter defaults to running. PMCR.DP says "disable
+         * the cycle counter when event counting is prohibited".
+         * Some MDCR bits disable the cycle counter specifically.
+         */
+        prohibited = prohibited && env->cp15.c9_pmcr & PMCRDP;
+        if (cpu_isar_feature(any_pmuv3p5, env_archcpu(env))) {
+            if (secure) {
+                prohibited = prohibited || (env->cp15.mdcr_el3 & MDCR_SCCD);
+            }
+            if (el == 2) {
+                prohibited = prohibited || (mdcr_el2 & MDCR_HCCD);
+            }
+        }
     }
 
     if (counter == 31) {