Extensible struct side_event_state

[libside.git] / src / side.c

diff --git a/src/side.c b/src/side.c
index 67a5bd459a15734e40287c72d57dc57d6a65c91b..d02a34f135b6ada078ed5821cdd5245c8cdad7a4 100644 (file)
--- a/src/side.c
+++ b/src/side.c
@@ -5,6 +5,7 @@
 
 #include <side/trace.h>
 #include <string.h>
+#include <assert.h>
 
 #include "rcu.h"
 #include "list.h"
@@ -62,9 +63,8 @@ static DEFINE_SIDE_LIST_HEAD(side_tracer_list);
  */
 const struct side_callback side_empty_callback = { };
 
-void side_call(const struct side_event_description *desc, const struct side_arg_vec *side_arg_vec)
+void side_call(const struct side_event_state *event_state, const struct side_arg_vec *side_arg_vec)
 {
-       struct side_event_state *event_state;
        struct side_rcu_read_state rcu_read_state;
        const struct side_callback *side_cb;
        uintptr_t enabled;
@@ -73,26 +73,21 @@ void side_call(const struct side_event_description *desc, const struct side_arg_
                return;
        if (side_unlikely(!initialized))
                side_init();
-       if (side_unlikely(desc->flags & SIDE_EVENT_FLAG_VARIADIC)) {
-               printf("ERROR: unexpected variadic event description\n");
-               abort();
-       }
-       event_state = side_ptr_get(desc->state);
+       assert(!(side_ptr_get(event_state->desc)->flags & SIDE_EVENT_FLAG_VARIADIC));
        enabled = __atomic_load_n(&event_state->enabled, __ATOMIC_RELAXED);
        if (side_unlikely(enabled & SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK)) {
                // TODO: call kernel write.
        }
        side_rcu_read_begin(&rcu_gp, &rcu_read_state);
-       for (side_cb = side_rcu_dereference(event_state->callbacks); side_cb->u.call != NULL; side_cb++)
-               side_cb->u.call(desc, side_arg_vec, side_cb->priv);
+       for (side_cb = side_rcu_dereference(side_ptr_get(event_state->callbacks)); side_cb->u.call != NULL; side_cb++)
+               side_cb->u.call(side_ptr_get(event_state->desc), side_arg_vec, side_cb->priv);
        side_rcu_read_end(&rcu_gp, &rcu_read_state);
 }
 
-void side_call_variadic(const struct side_event_description *desc,
+void side_call_variadic(const struct side_event_state *event_state,
        const struct side_arg_vec *side_arg_vec,
        const struct side_arg_dynamic_struct *var_struct)
 {
-       struct side_event_state *event_state;
        struct side_rcu_read_state rcu_read_state;
        const struct side_callback *side_cb;
        uintptr_t enabled;
@@ -101,18 +96,14 @@ void side_call_variadic(const struct side_event_description *desc,
                return;
        if (side_unlikely(!initialized))
                side_init();
-       if (side_unlikely(!(desc->flags & SIDE_EVENT_FLAG_VARIADIC))) {
-               printf("ERROR: unexpected non-variadic event description\n");
-               abort();
-       }
-       event_state = side_ptr_get(desc->state);
+       assert(side_ptr_get(event_state->desc)->flags & SIDE_EVENT_FLAG_VARIADIC);
        enabled = __atomic_load_n(&event_state->enabled, __ATOMIC_RELAXED);
        if (side_unlikely(enabled & SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK)) {
                // TODO: call kernel write.
        }
        side_rcu_read_begin(&rcu_gp, &rcu_read_state);
-       for (side_cb = side_rcu_dereference(event_state->callbacks); side_cb->u.call_variadic != NULL; side_cb++)
-               side_cb->u.call_variadic(desc, side_arg_vec, var_struct, side_cb->priv);
+       for (side_cb = side_rcu_dereference(side_ptr_get(event_state->callbacks)); side_cb->u.call_variadic != NULL; side_cb++)
+               side_cb->u.call_variadic(side_ptr_get(event_state->desc), side_arg_vec, var_struct, side_cb->priv);
        side_rcu_read_end(&rcu_gp, &rcu_read_state);
 }
 
@@ -124,7 +115,7 @@ const struct side_callback *side_tracer_callback_lookup(
        struct side_event_state *event_state = side_ptr_get(desc->state);
        const struct side_callback *cb;
 
-       for (cb = event_state->callbacks; cb->u.call != NULL; cb++) {
+       for (cb = side_ptr_get(event_state->callbacks); cb->u.call != NULL; cb++) {
                if ((void *) cb->u.call == call && cb->priv == priv)
                        return cb;
        }
@@ -148,7 +139,7 @@ int _side_tracer_callback_register(struct side_event_description *desc,
                side_init();
        pthread_mutex_lock(&side_lock);
        event_state = side_ptr_get(desc->state);
-       old_nr_cb = event_state->nr_callbacks;
+       old_nr_cb = desc->nr_callbacks;
        if (old_nr_cb == UINT32_MAX) {
                ret = SIDE_ERROR_INVAL;
                goto unlock;
@@ -158,7 +149,7 @@ int _side_tracer_callback_register(struct side_event_description *desc,
                ret = SIDE_ERROR_EXIST;
                goto unlock;
        }
-       old_cb = (struct side_callback *) event_state->callbacks;
+       old_cb = (struct side_callback *) side_ptr_get(event_state->callbacks);
        /* old_nr_cb + 1 (new cb) + 1 (NULL) */
        new_cb = (struct side_callback *) calloc(old_nr_cb + 2, sizeof(struct side_callback));
        if (!new_cb) {
@@ -173,11 +164,12 @@ int _side_tracer_callback_register(struct side_event_description *desc,
                new_cb[old_nr_cb].u.call =
                        (side_tracer_callback_func) call;
        new_cb[old_nr_cb].priv = priv;
-       side_rcu_assign_pointer(event_state->callbacks, new_cb);
+       /* High order bits are already zeroed. */
+       side_rcu_assign_pointer(side_ptr_get(event_state->callbacks), new_cb);
        side_rcu_wait_grace_period(&rcu_gp);
        if (old_nr_cb)
                free(old_cb);
-       event_state->nr_callbacks++;
+       desc->nr_callbacks++;
        /* Increment concurrently with kernel setting the top bits. */
        if (!old_nr_cb)
                (void) __atomic_add_fetch(&event_state->enabled, 1, __ATOMIC_RELAXED);
@@ -227,12 +219,12 @@ static int _side_tracer_callback_unregister(struct side_event_description *desc,
                ret = SIDE_ERROR_NOENT;
                goto unlock;
        }
-       old_nr_cb = event_state->nr_callbacks;
-       old_cb = (struct side_callback *) event_state->callbacks;
+       old_nr_cb = desc->nr_callbacks;
+       old_cb = (struct side_callback *) side_ptr_get(event_state->callbacks);
        if (old_nr_cb == 1) {
                new_cb = (struct side_callback *) &side_empty_callback;
        } else {
-               pos_idx = cb_pos - event_state->callbacks;
+               pos_idx = cb_pos - side_ptr_get(event_state->callbacks);
                /* Remove entry at pos_idx. */
                /* old_nr_cb - 1 (removed cb) + 1 (NULL) */
                new_cb = (struct side_callback *) calloc(old_nr_cb, sizeof(struct side_callback));
@@ -243,10 +235,11 @@ static int _side_tracer_callback_unregister(struct side_event_description *desc,
                memcpy(new_cb, old_cb, pos_idx);
                memcpy(&new_cb[pos_idx], &old_cb[pos_idx + 1], old_nr_cb - pos_idx - 1);
        }
-       side_rcu_assign_pointer(event_state->callbacks, new_cb);
+       /* High order bits are already zeroed. */
+       side_rcu_assign_pointer(side_ptr_get(event_state->callbacks), new_cb);
        side_rcu_wait_grace_period(&rcu_gp);
        free(old_cb);
-       event_state->nr_callbacks--;
+       desc->nr_callbacks--;
        /* Decrement concurrently with kernel setting the top bits. */
        if (old_nr_cb == 1)
                (void) __atomic_add_fetch(&event_state->enabled, -1, __ATOMIC_RELAXED);
@@ -304,20 +297,20 @@ static
 void side_event_remove_callbacks(struct side_event_description *desc)
 {
        struct side_event_state *event_state = side_ptr_get(desc->state);
-       uint32_t nr_cb = event_state->nr_callbacks;
+       uint32_t nr_cb = desc->nr_callbacks;
        struct side_callback *old_cb;
 
        if (!nr_cb)
                return;
-       old_cb = (struct side_callback *) event_state->callbacks;
+       old_cb = (struct side_callback *) side_ptr_get(event_state->callbacks);
        (void) __atomic_add_fetch(&event_state->enabled, -1, __ATOMIC_RELAXED);
        /*
         * Setting the state back to 0 cb and empty callbacks out of
         * caution. This should not matter because instrumentation is
         * unreachable.
         */
-       event_state->nr_callbacks = 0;
-       side_rcu_assign_pointer(event_state->callbacks, &side_empty_callback);
+       desc->nr_callbacks = 0;
+       side_rcu_assign_pointer(side_ptr_get(event_state->callbacks), &side_empty_callback);
        /*
         * No need to wait for grace period because instrumentation is
         * unreachable.