diff options
Diffstat (limited to 'include/linux/ftrace.h')
| -rw-r--r-- | include/linux/ftrace.h | 24 |
1 files changed, 22 insertions, 2 deletions
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 0e952958915..79fa10cbdcf 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -72,13 +72,33 @@ extern unsigned char *ftrace_nop_replace(void); extern unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr); extern int ftrace_dyn_arch_init(void *data); extern int ftrace_mcount_set(unsigned long *data); -extern int ftrace_modify_code(unsigned long ip, unsigned char *old_code, - unsigned char *new_code); extern int ftrace_update_ftrace_func(ftrace_func_t func); extern void ftrace_caller(void); extern void ftrace_call(void); extern void mcount_call(void); +/** + * ftrace_modify_code - modify code segment + * @ip: the address of the code segment + * @old_code: the contents of what is expected to be there + * @new_code: the code to patch in + * + * This is a very sensitive operation and great care needs + * to be taken by the arch. The operation should carefully + * read the location, check to see if what is read is indeed + * what we expect it to be, and then on success of the compare, + * it should write to the location. + * + * Return must be: + * 0 on success + * -EFAULT on error reading the location + * -EINVAL on a failed compare of the contents + * -EPERM on error writing to the location + * Any other value will be considered a failure. + */ +extern int ftrace_modify_code(unsigned long ip, unsigned char *old_code, + unsigned char *new_code); + extern int skip_trace(unsigned long ip); extern void ftrace_release(void *start, unsigned long size); |