[PATCH 05/12 v3] ftrace: use probe_kernel

Steven Rostedt
2008-10-23T13:39:36Z

[-- Attachment #1: ftrace-use-probe-kernel.patch --]
[-- Type: text/plain, Size: 1519 bytes --]

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

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
---
arch/x86/kernel/ftrace.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)

Index: linux-compile.git/arch/x86/kernel/ftrace.c
===================================================================
--- linux-compile.git.orig/arch/x86/kernel/ftrace.c 2008-10-23 09:26:22.000000000 -0400
+++ linux-compile.git/arch/x86/kernel/ftrace.c 2008-10-23 09:27:08.000000000 -0400
@@ -67,15 +67,14 @@ ftrace_modify_code(unsigned long ip, uns
* 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, uns
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();

--