aboutsummaryrefslogtreecommitdiff
path: root/kernel
diff options
context:
space:
mode:
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/ftrace.c108
1 files changed, 50 insertions, 58 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 5cbddb59e99..fdaab04a028 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -327,96 +327,89 @@ ftrace_record_ip(unsigned long ip)
static int
__ftrace_replace_code(struct dyn_ftrace *rec,
- unsigned char *old, unsigned char *new, int enable)
+ unsigned char *nop, int enable)
{
unsigned long ip, fl;
+ unsigned char *call, *old, *new;
ip = rec->ip;
- if (ftrace_filtered && enable) {
+ /*
+ * If this record is not to be traced and
+ * it is not enabled then do nothing.
+ *
+ * If this record is not to be traced and
+ * it is enabled then disabled it.
+ *
+ */
+ if (rec->flags & FTRACE_FL_NOTRACE) {
+ if (rec->flags & FTRACE_FL_ENABLED)
+ rec->flags &= ~FTRACE_FL_ENABLED;
+ else
+ return 0;
+
+ } else if (ftrace_filtered && enable) {
/*
- * If filtering is on:
- *
- * If this record is set to be filtered and
- * is enabled then do nothing.
- *
- * If this record is set to be filtered and
- * it is not enabled, enable it.
- *
- * If this record is not set to be filtered
- * and it is not enabled do nothing.
- *
- * If this record is set not to trace then
- * do nothing.
- *
- * If this record is set not to trace and
- * it is enabled then disable it.
- *
- * If this record is not set to be filtered and
- * it is enabled, disable it.
+ * Filtering is on:
*/
- fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_NOTRACE |
- FTRACE_FL_ENABLED);
+ fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED);
- if ((fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED)) ||
- (fl == (FTRACE_FL_FILTER | FTRACE_FL_NOTRACE)) ||
- !fl || (fl == FTRACE_FL_NOTRACE))
+ /* Record is filtered and enabled, do nothing */
+ if (fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED))
return 0;
- /*
- * If it is enabled disable it,
- * otherwise enable it!
- */
- if (fl & FTRACE_FL_ENABLED) {
- /* swap new and old */
- new = old;
- old = ftrace_call_replace(ip, FTRACE_ADDR);
+ /* Record is not filtered and is not enabled do nothing */
+ if (!fl)
+ return 0;
+
+ /* Record is not filtered but enabled, disable it */
+ if (fl == FTRACE_FL_ENABLED)
rec->flags &= ~FTRACE_FL_ENABLED;
- } else {
- new = ftrace_call_replace(ip, FTRACE_ADDR);
+ else
+ /* Otherwise record is filtered but not enabled, enable it */
rec->flags |= FTRACE_FL_ENABLED;
- }
} else {
+ /* Disable or not filtered */
if (enable) {
- /*
- * If this record is set not to trace and is
- * not enabled, do nothing.
- */
- fl = rec->flags & (FTRACE_FL_NOTRACE | FTRACE_FL_ENABLED);
- if (fl == FTRACE_FL_NOTRACE)
- return 0;
-
- new = ftrace_call_replace(ip, FTRACE_ADDR);
- } else
- old = ftrace_call_replace(ip, FTRACE_ADDR);
-
- if (enable) {
+ /* if record is enabled, do nothing */
if (rec->flags & FTRACE_FL_ENABLED)
return 0;
+
rec->flags |= FTRACE_FL_ENABLED;
+
} else {
+
+ /* if record is not enabled do nothing */
if (!(rec->flags & FTRACE_FL_ENABLED))
return 0;
+
rec->flags &= ~FTRACE_FL_ENABLED;
}
}
+ call = ftrace_call_replace(ip, FTRACE_ADDR);
+
+ if (rec->flags & FTRACE_FL_ENABLED) {
+ old = nop;
+ new = call;
+ } else {
+ old = call;
+ new = nop;
+ }
+
return ftrace_modify_code(ip, old, new);
}
static void ftrace_replace_code(int enable)
{
int i, failed;
- unsigned char *new = NULL, *old = NULL;
+ unsigned char *nop = NULL;
struct dyn_ftrace *rec;
struct ftrace_page *pg;
- if (enable)
- old = ftrace_nop_replace();
- else
- new = ftrace_nop_replace();
+ nop = ftrace_nop_replace();
for (pg = ftrace_pages_start; pg; pg = pg->next) {
for (i = 0; i < pg->index; i++) {
@@ -434,7 +427,7 @@ static void ftrace_replace_code(int enable)
unfreeze_record(rec);
}
- failed = __ftrace_replace_code(rec, old, new, enable);
+ failed = __ftrace_replace_code(rec, nop, enable);
if (failed && (rec->flags & FTRACE_FL_CONVERTED)) {
rec->flags |= FTRACE_FL_FAILED;
if ((system_state == SYSTEM_BOOTING) ||
@@ -538,8 +531,7 @@ static void ftrace_startup(void)
mutex_lock(&ftrace_start_lock);
ftrace_start++;
- if (ftrace_start == 1)
- command |= FTRACE_ENABLE_CALLS;
+ command |= FTRACE_ENABLE_CALLS;
if (saved_ftrace_func != ftrace_trace_function) {
saved_ftrace_func = ftrace_trace_function;