ftrace: Consolidate ftrace_location() and ftrace_text_reserved()
Both ftrace_location() and ftrace_text_reserved() do basically the same thing.
They search to see if an address is in the ftace table (contains an address
that may change from nop to call ftrace_caller). The difference is
that ftrace_location() searches a single address, but ftrace_text_reserved()
searches a range.
This also makes the ftrace_text_reserved() faster as it now uses a bsearch()
instead of linearly searching all the addresses within a page.
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index fc93562..dd091c8 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1383,13 +1383,36 @@
static int ftrace_cmp_recs(const void *a, const void *b)
{
- const struct dyn_ftrace *reca = a;
- const struct dyn_ftrace *recb = b;
+ const struct dyn_ftrace *key = a;
+ const struct dyn_ftrace *rec = b;
- if (reca->ip > recb->ip)
- return 1;
- if (reca->ip < recb->ip)
+ if (key->flags < rec->ip)
return -1;
+ if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
+ return 1;
+ return 0;
+}
+
+static int ftrace_location_range(unsigned long start, unsigned long end)
+{
+ struct ftrace_page *pg;
+ struct dyn_ftrace *rec;
+ struct dyn_ftrace key;
+
+ key.ip = start;
+ key.flags = end; /* overload flags, as it is unsigned long */
+
+ for (pg = ftrace_pages_start; pg; pg = pg->next) {
+ if (end < pg->records[0].ip ||
+ start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
+ continue;
+ rec = bsearch(&key, pg->records, pg->index,
+ sizeof(struct dyn_ftrace),
+ ftrace_cmp_recs);
+ if (rec)
+ return 1;
+ }
+
return 0;
}
@@ -1404,23 +1427,23 @@
*/
int ftrace_location(unsigned long ip)
{
- struct ftrace_page *pg;
- struct dyn_ftrace *rec;
- struct dyn_ftrace key;
+ return ftrace_location_range(ip, ip);
+}
- key.ip = ip;
-
- for (pg = ftrace_pages_start; pg; pg = pg->next) {
- if (ip < pg->records[0].ip || ip > pg->records[pg->index - 1].ip)
- continue;
- rec = bsearch(&key, pg->records, pg->index,
- sizeof(struct dyn_ftrace),
- ftrace_cmp_recs);
- if (rec)
- return 1;
- }
-
- return 0;
+/**
+ * ftrace_text_reserved - return true if range contains an ftrace location
+ * @start: start of range to search
+ * @end: end of range to search (inclusive). @end points to the last byte to check.
+ *
+ * Returns 1 if @start and @end contains 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_text_reserved(void *start, void *end)
+{
+ return ftrace_location_range((unsigned long)start,
+ (unsigned long)end);
}
static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
@@ -1571,29 +1594,6 @@
}
}
-
-/* Return 1 if the address range is reserved for ftrace */
-int ftrace_text_reserved(void *s, void *e)
-{
- struct dyn_ftrace *rec;
- struct ftrace_page *pg;
- unsigned long start = (unsigned long)s;
- unsigned long end = (unsigned long)e;
- int i;
-
- for (pg = ftrace_pages_start; pg; pg = pg->next) {
- if (end < pg->records[0].ip ||
- start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
- continue;
- for (i = 0; i < pg->index; i++) {
- rec = &pg->records[i];
- if (rec->ip <= end && rec->ip + MCOUNT_INSN_SIZE > start)
- return 1;
- }
- }
- return 0;
-}
-
static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
{
unsigned long flag = 0UL;