[PATCH 05/11] target/hexagon: take BQL when reading the system pcycle count

[Brian Cain <brian.cain@oss.qualcomm.com>]

hexagon_get_sys_pcycle_count() iterates all CPUs, so take the BQL with
BQL_LOCK_GUARD() instead of asserting the caller already holds it.
Convert the matching setters the same way, which keeps the locking
contract symmetric and makes the read-modify-write in the _low/_high
setters atomic.  BQL_LOCK_GUARD() is a no-op when the lock is already
held, so the nested guards on the guest-register read path cost nothing.

Signed-off-by: Brian Cain <brian.cain@oss.qualcomm.com>
---
 target/hexagon/cpu_helper.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/target/hexagon/cpu_helper.c b/target/hexagon/cpu_helper.c
index 64c5746c6d9..649c583c0fa 100644
--- a/target/hexagon/cpu_helper.c
+++ b/target/hexagon/cpu_helper.c
@@ -36,7 +36,7 @@ uint64_t hexagon_get_sys_pcycle_count(CPUHexagonState *env)
     uint64_t total = 0;
     CPUState *cs;
 
-    g_assert(bql_locked());
+    BQL_LOCK_GUARD();
     CPU_FOREACH(cs) {
         CPUHexagonState *thread_env = cpu_env(cs);
         total += thread_env->t_cycle_count;
@@ -54,11 +54,15 @@ uint32_t hexagon_get_sys_pcycle_count_low(CPUHexagonState *env)
     return (uint32_t)(hexagon_get_sys_pcycle_count(env));
 }
 
+/*
+ * Every function in this family takes the BQL itself, so the guard below
+ * holds it across the read-modify-write.  Nested guards are no-ops.
+ */
 void hexagon_set_sys_pcycle_count_high(CPUHexagonState *env, uint32_t val)
 {
     uint64_t old;
 
-    g_assert(bql_locked());
+    BQL_LOCK_GUARD();
     old = hexagon_get_sys_pcycle_count(env);
     old = deposit64(old, 32, 32, val);
     hexagon_set_sys_pcycle_count(env, old);
@@ -68,7 +72,7 @@ void hexagon_set_sys_pcycle_count_low(CPUHexagonState *env, uint32_t val)
 {
     uint64_t old;
 
-    g_assert(bql_locked());
+    BQL_LOCK_GUARD();
     old = hexagon_get_sys_pcycle_count(env);
     old = deposit64(old, 0, 32, val);
     hexagon_set_sys_pcycle_count(env, old);
@@ -81,7 +85,7 @@ void hexagon_set_sys_pcycle_count(CPUHexagonState *env, uint64_t val)
     int num_threads;
     int64_t delta, per_thread, remainder;
 
-    g_assert(bql_locked());
+    BQL_LOCK_GUARD();
     total = hexagon_get_sys_pcycle_count(env);
 
     /* Count active threads */
-- 
2.34.1