target/arm: Add pre-EL change hooks

Because the design of the PMU requires that the counter values be
converted between their delta and guest-visible forms for mode
filtering, an additional hook which occurs before the EL is changed is
necessary.

Signed-off-by: Aaron Lindsay <alindsay@codeaurora.org>
Message-id: 1523997485-1905-8-git-send-email-alindsay@codeaurora.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 16 insertions, 0 deletions

diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index 1f689f6817..d175c5e94f 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -55,6 +55,17 @@ static bool arm_cpu_has_work(CPUState *cs)
          | CPU_INTERRUPT_EXITTB);
 }
 
+void arm_register_pre_el_change_hook(ARMCPU *cpu, ARMELChangeHookFn *hook,
+                                 void *opaque)
+{
+    ARMELChangeHook *entry = g_new0(ARMELChangeHook, 1);
+
+    entry->hook = hook;
+    entry->opaque = opaque;
+
+    QLIST_INSERT_HEAD(&cpu->pre_el_change_hooks, entry, node);
+}
+
 void arm_register_el_change_hook(ARMCPU *cpu, ARMELChangeHookFn *hook,
                                  void *opaque)
 {
@@ -554,6 +565,7 @@ static void arm_cpu_initfn(Object *obj)
     cpu->cp_regs = g_hash_table_new_full(g_int_hash, g_int_equal,
                                          g_free, g_free);
 
+    QLIST_INIT(&cpu->pre_el_change_hooks);
     QLIST_INIT(&cpu->el_change_hooks);
 
 #ifndef CONFIG_USER_ONLY
@@ -721,6 +733,10 @@ static void arm_cpu_finalizefn(Object *obj)
 
     g_hash_table_destroy(cpu->cp_regs);
 
+    QLIST_FOREACH_SAFE(hook, &cpu->pre_el_change_hooks, node, next) {
+        QLIST_REMOVE(hook, node);
+        g_free(hook);
+    }
     QLIST_FOREACH_SAFE(hook, &cpu->el_change_hooks, node, next) {
         QLIST_REMOVE(hook, node);
         g_free(hook);