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ftrace: use probe_kernel

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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>
This commit is contained in:
Steven Rostedt
2008-10-23 09:33:01 -04:00
committed by Ingo Molnar
parent 76aefee576
commit ab9a0918cb
1 changed files with 3 additions and 5 deletions
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8
arch/x86/kernel/ftrace.c
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@@ -67,15 +67,14 @@ ftrace_modify_code(unsigned long ip, unsigned char *old_code,
* Note: Due to modules and __init, code can * Note: Due to modules and __init, code can
* disappear and change, we need to protect against faulting * disappear and change, we need to protect against faulting
* as well as code changing. We do this by using the * 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 * No real locking needed, this code is run through
* kstop_machine, or before SMP starts. * kstop_machine, or before SMP starts.
*/ */
/* read the text we want to modify */ /* read the text we want to modify */
if (__copy_from_user_inatomic(replaced, (char __user *)ip, if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE))
MCOUNT_INSN_SIZE))
return -EFAULT; return -EFAULT;
/* Make sure it is what we expect it to be */ /* 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; return -EINVAL;
/* replace the text with the new text */ /* replace the text with the new text */
if (__copy_to_user_inatomic((char __user *)ip, new_code, if (probe_kernel_write((void *)ip, new_code, MCOUNT_INSN_SIZE))
MCOUNT_INSN_SIZE))
return -EPERM; return -EPERM;
sync_core(); sync_core();