target/arm: Don't clear supported PMU events when initializing PMCEID1

A bug was introduced during a respin of:

commit 57a4a11b2b281bb548b419ca81bfafb214e4c77a
target/arm: Add array for supported PMU events, generate PMCEID[01]_EL0

This patch introduced two calls to get_pmceid() during CPU
initialization - one each for PMCEID0 and PMCEID1. In addition to
building the register values, get_pmceid() clears an internal array
mapping event numbers to their implementations (supported_event_map)
before rebuilding it. This is an optimization since much of the logic is
shared. However, since it was called twice, the contents of
supported_event_map reflect only the events in PMCEID1 (the second call
to get_pmceid()).

Fix this bug by moving the initialization of PMCEID0 and PMCEID1 back
into a single function call, and name it more appropriately since it is
doing more than simply generating the contents of the PMCEID[01]
registers.

Backports commit bf8d09694ccc07487cd73d7562081fdaec3370c8 from qemu

qemu/aarch64.h

@@ -3337,7 +3337,7 @@
 #define fp_exception_el fp_exception_el_aarch64
 #define gen_a64_set_pc_im gen_a64_set_pc_im_aarch64
 #define gen_cmtst_i64 gen_cmtst_i64_aarch64
-#define get_pmceid get_pmceid_aarch64
+#define pmu_init pmu_init_aarch64
 #define helper_advsimd_acge_f16 helper_advsimd_acge_f16_aarch64
 #define helper_advsimd_acgt_f16 helper_advsimd_acgt_f16_aarch64
 #define helper_advsimd_add2h helper_advsimd_add2h_aarch64

qemu/aarch64eb.h

@@ -3337,7 +3337,7 @@
 #define fp_exception_el fp_exception_el_aarch64eb
 #define gen_a64_set_pc_im gen_a64_set_pc_im_aarch64eb
 #define gen_cmtst_i64 gen_cmtst_i64_aarch64eb
-#define get_pmceid get_pmceid_aarch64eb
+#define pmu_init pmu_init_aarch64eb
 #define helper_advsimd_acge_f16 helper_advsimd_acge_f16_aarch64eb
 #define helper_advsimd_acgt_f16 helper_advsimd_acgt_f16_aarch64eb
 #define helper_advsimd_add2h helper_advsimd_add2h_aarch64eb

qemu/arm.h

@@ -3322,7 +3322,7 @@
 #define cmtst_op cmtst_op_arm
 #define fp_exception_el fp_exception_el_arm
 #define gen_cmtst_i64 gen_cmtst_i64_arm
-#define get_pmceid get_pmceid_arm
+#define pmu_init pmu_init_arm
 #define mla_op mla_op_arm
 #define mls_op mls_op_arm
 #define pmccntr_op_start pmccntr_op_start_arm

qemu/armeb.h

@@ -3322,7 +3322,7 @@
 #define cmtst_op cmtst_op_armeb
 #define fp_exception_el fp_exception_el_armeb
 #define gen_cmtst_i64 gen_cmtst_i64_armeb
-#define get_pmceid get_pmceid_armeb
+#define pmu_init pmu_init_armeb
 #define mla_op mla_op_armeb
 #define mls_op mls_op_armeb
 #define pmccntr_op_start pmccntr_op_start_armeb

qemu/header_gen.py

@@ -3331,7 +3331,7 @@ arm_symbols = (
     'cmtst_op',
     'fp_exception_el',
     'gen_cmtst_i64',
-    'get_pmceid',
+    'pmu_init',
     'mla_op',
     'mls_op',
     'pmccntr_op_start',
@@ -3383,7 +3383,7 @@ aarch64_symbols = (
     'fp_exception_el',
     'gen_a64_set_pc_im',
     'gen_cmtst_i64',
-    'get_pmceid',
+    'pmu_init',
     'helper_advsimd_acge_f16',
     'helper_advsimd_acgt_f16',
     'helper_advsimd_add2h',

qemu/target/arm/cpu.c

@@ -764,8 +764,7 @@ static int arm_cpu_realizefn(struct uc_struct *uc, DeviceState *dev, Error **err
     }
 
     if (arm_feature(env, ARM_FEATURE_PMU)) {
-        cpu->pmceid0 = get_pmceid(&cpu->env, 0);
+        pmu_init(cpu);
-        cpu->pmceid1 = get_pmceid(&cpu->env, 1);
 
         arm_register_pre_el_change_hook(cpu, &pmu_pre_el_change, 0);
         arm_register_el_change_hook(cpu, &pmu_post_el_change, 0);

qemu/target/arm/cpu.h

@@ -964,14 +964,13 @@ void pmu_pre_el_change(ARMCPU *cpu, void *ignored);
 void pmu_post_el_change(ARMCPU *cpu, void *ignored);
 
 /*
- * get_pmceid
+ * pmu_init
- * @env: CPUARMState
+ * @cpu: ARMCPU
- * @which: which PMCEID register to return (0 or 1)
  *
- * Return the PMCEID[01]_EL0 register values corresponding to the counters
+ * Initialize the CPU's PMCEID[01]_EL0 registers and associated internal state
- * which are supported given the current configuration
+ * for the current configuration
  */
-uint64_t get_pmceid(CPUARMState *env, unsigned which);
+void pmu_init(ARMCPU *cpu);
 
 /* SCTLR bit meanings. Several bits have been reused in newer
  * versions of the architecture; in that case we define constants

qemu/target/arm/helper.c

@@ -952,22 +952,24 @@ static const pm_event pm_events[] = {
 #define UNSUPPORTED_EVENT UINT16_MAX
 
 /*
- * Called upon initialization to build PMCEID0_EL0 or PMCEID1_EL0 (indicated by
+ * Called upon CPU initialization to initialize PMCEID[01]_EL0 and build a map
- * 'which'). We also use it to build a map of ARM event numbers to indices in
+ * of ARM event numbers to indices in our pm_events array.
- * our pm_events array.
  *
  * Note: Events in the 0x40XX range are not currently supported.
  */
-uint64_t get_pmceid(CPUARMState *env, unsigned which)
+void pmu_init(ARMCPU *cpu)
 {
-    uint64_t pmceid = 0;
     unsigned int i;
 
-    assert(which <= 1);
+    /*
-
+     * Empty supported_event_map and cpu->pmceid[01] before adding supported
-    for (i = 0; i < ARRAY_SIZE(env->supported_event_map); i++) {
+     * events to them
-        env->supported_event_map[i] = UNSUPPORTED_EVENT;
+     */
+    for (i = 0; i < ARRAY_SIZE(cpu->env.supported_event_map); i++) {
+        cpu->env.supported_event_map[i] = UNSUPPORTED_EVENT;
     }
+    cpu->pmceid0 = 0;
+    cpu->pmceid1 = 0;
 
     for (i = 0; i < ARRAY_SIZE(pm_events); i++) {
         const pm_event *cnt = &pm_events[i];
@@ -975,13 +977,16 @@ uint64_t get_pmceid(CPUARMState *env, unsigned which)
         /* We do not currently support events in the 0x40xx range */
         assert(cnt->number <= 0x3f);
 
-        if ((cnt->number & 0x20) == (which << 6) &&
+        if (cnt->supported(&cpu->env)) {
-                cnt->supported(env)) {
+            cpu->env.supported_event_map[cnt->number] = i;
-            pmceid |= (1 << (cnt->number & 0x1f));
+            uint64_t event_mask = 1 << (cnt->number & 0x1f);
-            env->supported_event_map[cnt->number] = i;
+            if (cnt->number & 0x20) {
+                cpu->pmceid1 |= event_mask;
+            } else {
+                cpu->pmceid0 |= event_mask;
+            }
         }
     }
-    return pmceid;
 }
 
 /*