ftrace: use probe_kernel

Andrew Morton suggested using the proper API for reading and writing
kernel areas that might fault.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 3 insertions, 5 deletions

diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 783455454d78..da4fb0deecf7 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -67,15 +67,14 @@ ftrace_modify_code(unsigned long ip, unsigned char *old_code,
          * Note: Due to modules and __init, code can
          *  disappear and change, we need to protect against faulting
          *  as well as code changing. We do this by using the
-         *  __copy_*_user functions.
+         *  probe_kernel_* functions.
          *
          * No real locking needed, this code is run through
          * kstop_machine, or before SMP starts.
          */
 
         /* read the text we want to modify */
-        if (__copy_from_user_inatomic(replaced, (char __user *)ip,
-                                      MCOUNT_INSN_SIZE))
+        if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE))
                 return -EFAULT;
 
         /* Make sure it is what we expect it to be */
@@ -83,8 +82,7 @@ ftrace_modify_code(unsigned long ip, unsigned char *old_code,
                 return -EINVAL;
 
         /* replace the text with the new text */
-        if (__copy_to_user_inatomic((char __user *)ip, new_code,
-                                    MCOUNT_INSN_SIZE))
+        if (probe_kernel_write((void *)ip, new_code, MCOUNT_INSN_SIZE))
                 return -EPERM;
 
         sync_core();