Adding modify_ftrace_direct_hash function that modifies
all entries (ip -> direct) provided in hash argument.
The difference to current unregister_ftrace_direct is
- hash argument that allows to modify multiple ip -> direct
entries at once
This change will allow us to have simple ftrace_ops for all bpf
direct interface users in following changes.
Signed-off-by: Jiri Olsa <jo...@kernel.org>
---
include/linux/ftrace.h | 6 +++++
kernel/trace/ftrace.c | 58 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 64 insertions(+)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 7ff6004498c0..8761765d9abc 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -528,6 +528,7 @@ int modify_ftrace_direct_nolock(struct ftrace_ops *ops,
unsigned long addr);
int register_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash
*hash);
int unregister_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash
*hash);
+int modify_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash
*hash, bool do_direct_lock);
void ftrace_stub_direct_tramp(void);
@@ -565,6 +566,11 @@ int unregister_ftrace_direct_hash(struct ftrace_ops *ops,
struct ftrace_hash *ha
return -ENODEV;
}
+int modify_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash
*hash, bool do_direct_lock)
+{
+ return -ENODEV;
+}
+
/*
* This must be implemented by the architecture.
* It is the way the ftrace direct_ops helper, when called
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index d761237ec70f..755d5550ac44 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -6440,6 +6440,64 @@ int unregister_ftrace_direct_hash(struct ftrace_ops
*ops, struct ftrace_hash *ha
}
EXPORT_SYMBOL_GPL(unregister_ftrace_direct_hash);
+int modify_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash
*hash, bool do_direct_lock)
+{
+ struct ftrace_func_entry *entry, *tmp;
+ static struct ftrace_ops tmp_ops = {
+ .func = ftrace_stub,
+ .flags = FTRACE_OPS_FL_STUB,
+ };
+ unsigned long size, i;
+ int err;
+
+ if (!hash_count(hash))
+ return 0;
+ if (check_direct_multi(ops))
+ return -EINVAL;
+ if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
+ return -EINVAL;
+ if (direct_functions == EMPTY_HASH)
+ return -EINVAL;
+
+ if (do_direct_lock)
+ mutex_lock(&direct_mutex);
+
+ /* Enable the tmp_ops to have the same functions as the direct ops */
+ ftrace_ops_init(&tmp_ops);
+ tmp_ops.func_hash = ops->func_hash;
+
+ err = register_ftrace_function_nolock(&tmp_ops);
+ if (err)
+ goto unlock;
+
+ /*
+ * Now the ftrace_ops_list_func() is called to do the direct callers.
+ * We can safely change the direct functions attached to each entry.
+ */
+ mutex_lock(&ftrace_lock);
+
+ size = 1 << hash->size_bits;
+ for (i = 0; i < size; i++) {
+ hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
+ tmp = __ftrace_lookup_ip(direct_functions, entry->ip);
+ if (!tmp)
+ continue;
+ tmp->direct = entry->direct;
+ }
+ }
+
+ mutex_unlock(&ftrace_lock);
+
+ /* Removing the tmp_ops will add the updated direct callers to the
functions */
+ unregister_ftrace_function(&tmp_ops);
+
+unlock:
+ if (do_direct_lock)
+ mutex_unlock(&direct_mutex);
+ return err;
+}
+EXPORT_SYMBOL_GPL(modify_ftrace_direct_hash);
+
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
/**
--
2.50.1
