struct rcu_head rcu;
};
-enum {
- FTRACE_UPDATE_CALLS = (1 << 0),
- FTRACE_DISABLE_CALLS = (1 << 1),
- FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
- FTRACE_START_FUNC_RET = (1 << 3),
- FTRACE_STOP_FUNC_RET = (1 << 4),
-};
struct ftrace_func_entry {
struct hlist_node hlist;
unsigned long ip;
} \
}
+/**
+ * ftrace_location - return true if the ip giving is a traced location
+ * @ip: the instruction pointer to check
+ *
+ * Returns 1 if @ip given is a pointer to a ftrace location.
+ * That is, the instruction that is either a NOP or call to
+ * the function tracer. It checks the ftrace internal tables to
+ * determine if the address belongs or not.
+ */
+int ftrace_location(unsigned long ip)
+{
+ struct ftrace_page *pg;
+ struct dyn_ftrace *rec;
+
+ do_for_each_ftrace_rec(pg, rec) {
+ if (rec->ip == ip)
+ return 1;
+ } while_for_each_ftrace_rec();
+
+ return 0;
+}
+
static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
int filter_hash,
bool inc)
printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
}
-static void ftrace_bug(int failed, unsigned long ip)
+/**
+ * ftrace_bug - report and shutdown function tracer
+ * @failed: The failed type (EFAULT, EINVAL, EPERM)
+ * @ip: The address that failed
+ *
+ * The arch code that enables or disables the function tracing
+ * can call ftrace_bug() when it has detected a problem in
+ * modifying the code. @failed should be one of either:
+ * EFAULT - if the problem happens on reading the @ip address
+ * EINVAL - if what is read at @ip is not what was expected
+ * EPERM - if the problem happens on writting to the @ip address
+ */
+void ftrace_bug(int failed, unsigned long ip)
{
switch (failed) {
case -EFAULT:
return 0;
}
-
-static int
-__ftrace_replace_code(struct dyn_ftrace *rec, int update)
+static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
{
- unsigned long ftrace_addr;
unsigned long flag = 0UL;
- ftrace_addr = (unsigned long)FTRACE_ADDR;
-
/*
* If we are updating calls:
*
* If we are disabling calls, then disable all records that
* are enabled.
*/
- if (update && (rec->flags & ~FTRACE_FL_MASK))
+ if (enable && (rec->flags & ~FTRACE_FL_MASK))
flag = FTRACE_FL_ENABLED;
/* If the state of this record hasn't changed, then do nothing */
if ((rec->flags & FTRACE_FL_ENABLED) == flag)
- return 0;
+ return FTRACE_UPDATE_IGNORE;
if (flag) {
- rec->flags |= FTRACE_FL_ENABLED;
+ if (update)
+ rec->flags |= FTRACE_FL_ENABLED;
+ return FTRACE_UPDATE_MAKE_CALL;
+ }
+
+ if (update)
+ rec->flags &= ~FTRACE_FL_ENABLED;
+
+ return FTRACE_UPDATE_MAKE_NOP;
+}
+
+/**
+ * ftrace_update_record, set a record that now is tracing or not
+ * @rec: the record to update
+ * @enable: set to 1 if the record is tracing, zero to force disable
+ *
+ * The records that represent all functions that can be traced need
+ * to be updated when tracing has been enabled.
+ */
+int ftrace_update_record(struct dyn_ftrace *rec, int enable)
+{
+ return ftrace_check_record(rec, enable, 1);
+}
+
+/**
+ * ftrace_test_record, check if the record has been enabled or not
+ * @rec: the record to test
+ * @enable: set to 1 to check if enabled, 0 if it is disabled
+ *
+ * The arch code may need to test if a record is already set to
+ * tracing to determine how to modify the function code that it
+ * represents.
+ */
+int ftrace_test_record(struct dyn_ftrace *rec, int enable)
+{
+ return ftrace_check_record(rec, enable, 0);
+}
+
+static int
+__ftrace_replace_code(struct dyn_ftrace *rec, int enable)
+{
+ unsigned long ftrace_addr;
+ int ret;
+
+ ftrace_addr = (unsigned long)FTRACE_ADDR;
+
+ ret = ftrace_update_record(rec, enable);
+
+ switch (ret) {
+ case FTRACE_UPDATE_IGNORE:
+ return 0;
+
+ case FTRACE_UPDATE_MAKE_CALL:
return ftrace_make_call(rec, ftrace_addr);
+
+ case FTRACE_UPDATE_MAKE_NOP:
+ return ftrace_make_nop(NULL, rec, ftrace_addr);
}
- rec->flags &= ~FTRACE_FL_ENABLED;
- return ftrace_make_nop(NULL, rec, ftrace_addr);
+ return -1; /* unknow ftrace bug */
}
static void ftrace_replace_code(int update)
} while_for_each_ftrace_rec();
}
+struct ftrace_rec_iter {
+ struct ftrace_page *pg;
+ int index;
+};
+
+/**
+ * ftrace_rec_iter_start, start up iterating over traced functions
+ *
+ * Returns an iterator handle that is used to iterate over all
+ * the records that represent address locations where functions
+ * are traced.
+ *
+ * May return NULL if no records are available.
+ */
+struct ftrace_rec_iter *ftrace_rec_iter_start(void)
+{
+ /*
+ * We only use a single iterator.
+ * Protected by the ftrace_lock mutex.
+ */
+ static struct ftrace_rec_iter ftrace_rec_iter;
+ struct ftrace_rec_iter *iter = &ftrace_rec_iter;
+
+ iter->pg = ftrace_pages_start;
+ iter->index = 0;
+
+ /* Could have empty pages */
+ while (iter->pg && !iter->pg->index)
+ iter->pg = iter->pg->next;
+
+ if (!iter->pg)
+ return NULL;
+
+ return iter;
+}
+
+/**
+ * ftrace_rec_iter_next, get the next record to process.
+ * @iter: The handle to the iterator.
+ *
+ * Returns the next iterator after the given iterator @iter.
+ */
+struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
+{
+ iter->index++;
+
+ if (iter->index >= iter->pg->index) {
+ iter->pg = iter->pg->next;
+ iter->index = 0;
+
+ /* Could have empty pages */
+ while (iter->pg && !iter->pg->index)
+ iter->pg = iter->pg->next;
+ }
+
+ if (!iter->pg)
+ return NULL;
+
+ return iter;
+}
+
+/**
+ * ftrace_rec_iter_record, get the record at the iterator location
+ * @iter: The current iterator location
+ *
+ * Returns the record that the current @iter is at.
+ */
+struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
+{
+ return &iter->pg->records[iter->index];
+}
+
static int
ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
{
{
int *command = data;
- /*
- * Do not call function tracer while we update the code.
- * We are in stop machine, no worrying about races.
- */
- function_trace_stop++;
-
if (*command & FTRACE_UPDATE_CALLS)
ftrace_replace_code(1);
else if (*command & FTRACE_DISABLE_CALLS)
else if (*command & FTRACE_STOP_FUNC_RET)
ftrace_disable_ftrace_graph_caller();
-#ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
- /*
- * For archs that call ftrace_test_stop_func(), we must
- * wait till after we update all the function callers
- * before we update the callback. This keeps different
- * ops that record different functions from corrupting
- * each other.
- */
- __ftrace_trace_function = __ftrace_trace_function_delay;
-#endif
- function_trace_stop--;
-
return 0;
}
+/**
+ * ftrace_run_stop_machine, go back to the stop machine method
+ * @command: The command to tell ftrace what to do
+ *
+ * If an arch needs to fall back to the stop machine method, the
+ * it can call this function.
+ */
+void ftrace_run_stop_machine(int command)
+{
+ stop_machine(__ftrace_modify_code, &command, NULL);
+}
+
+/**
+ * arch_ftrace_update_code, modify the code to trace or not trace
+ * @command: The command that needs to be done
+ *
+ * Archs can override this function if it does not need to
+ * run stop_machine() to modify code.
+ */
+void __weak arch_ftrace_update_code(int command)
+{
+ ftrace_run_stop_machine(command);
+}
+
static void ftrace_run_update_code(int command)
{
int ret;
FTRACE_WARN_ON(ret);
if (ret)
return;
+ /*
+ * Do not call function tracer while we update the code.
+ * We are in stop machine.
+ */
+ function_trace_stop++;
- stop_machine(__ftrace_modify_code, &command, NULL);
+ /*
+ * By default we use stop_machine() to modify the code.
+ * But archs can do what ever they want as long as it
+ * is safe. The stop_machine() is the safest, but also
+ * produces the most overhead.
+ */
+ arch_ftrace_update_code(command);
+
+#ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
+ /*
+ * For archs that call ftrace_test_stop_func(), we must
+ * wait till after we update all the function callers
+ * before we update the callback. This keeps different
+ * ops that record different functions from corrupting
+ * each other.
+ */
+ __ftrace_trace_function = __ftrace_trace_function_delay;
+#endif
+ function_trace_stop--;
ret = ftrace_arch_code_modify_post_process();
FTRACE_WARN_ON(ret);
projects / linux.git / commitdiff