ftrace_lookup_mcount() will return an address of mcount call in a function.
Signed-off-by: AKASHI Takahiro takahiro.akashi@linaro.org --- include/linux/ftrace.h | 2 ++ kernel/trace/ftrace.c | 26 ++++++++++++++++++++++++++ 2 files changed, 28 insertions(+)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 1da6029..1d0271f 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -699,6 +699,8 @@ static inline void __ftrace_enabled_restore(int enabled) # define trace_preempt_off(a0, a1) do { } while (0) #endif
+extern unsigned long ftrace_lookup_mcount(unsigned long addr); + #ifdef CONFIG_FTRACE_MCOUNT_RECORD extern void ftrace_init(void); #else diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 4f22802..fcfb04f 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -4857,6 +4857,32 @@ static int ftrace_process_locs(struct module *mod, return ret; }
+unsigned long ftrace_lookup_mcount(unsigned long addr) +{ + struct ftrace_page *pg; + struct dyn_ftrace *rec; + char str[KSYM_SYMBOL_LEN]; + char *modname; + const char *name; + unsigned long mcount = 0; + unsigned long offset; + + mutex_lock(&ftrace_lock); + + do_for_each_ftrace_rec(pg, rec) { + name = kallsyms_lookup(rec->ip, NULL, &offset, &modname, str); + if (name && rec->ip == (addr + offset)) { + mcount = rec->ip; + goto out_unlock; + } + } while_for_each_ftrace_rec(); + + out_unlock: + mutex_unlock(&ftrace_lock); + + return mcount; +} + #ifdef CONFIG_MODULES
#define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)