From: Song Liu <song@xxxxxxxxxx>
ftrace_process_locs sorts module mcount, which is inside RO memory. Add a
ftrace_swap_func so that archs can use RO-memory-poke function to do the
sorting.
Signed-off-by: Song Liu <song@xxxxxxxxxx>
---
include/linux/ftrace.h | 2 ++
kernel/trace/ftrace.c | 13 ++++++++++++-
2 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index b23bdd414394..fe443b8ed32c 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -1166,4 +1166,6 @@ unsigned long arch_syscall_addr(int nr);
#endif /* CONFIG_FTRACE_SYSCALLS */
+void ftrace_swap_func(void *a, void *b, int n);
+
#endif /* _LINUX_FTRACE_H */
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 764668467155..f5ddc9d4cfb6 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -6430,6 +6430,17 @@ static void test_is_sorted(unsigned long *start, unsigned long count)
}
#endif
+void __weak ftrace_swap_func(void *a, void *b, int n)
+{
+ unsigned long t;
+
+ WARN_ON_ONCE(n != sizeof(t));
+
+ t = *((unsigned long *)a);
+ *(unsigned long *)a = *(unsigned long *)b;
+ *(unsigned long *)b = t;
+}
+
static int ftrace_process_locs(struct module *mod,
unsigned long *start,
unsigned long *end)
@@ -6455,7 +6466,7 @@ static int ftrace_process_locs(struct module *mod,
*/
if (!IS_ENABLED(CONFIG_BUILDTIME_MCOUNT_SORT) || mod) {
sort(start, count, sizeof(*start),
- ftrace_cmp_ips, NULL);
+ ftrace_cmp_ips, ftrace_swap_func);
} else {
test_is_sorted(start, count);
}
--
2.35.1
