[PATCH -tip v2 1/3] kprobes: Introduce nokprobe annotation for non-probe-able functions

[Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>]

Instead of __kprobes annotation, introduce 'nokprobe' new annotation
to annotate that the function is not probed by kprobes.

Previously the '__kprobes' is used just for avoiding probes on
kprobes-related functions which will be used from kprobes. However
nowadays we use it for prohibiting probing the functions implicitly
invoked from kprobes int3 handler, since that causes infinit-loop
lockup or sudden reboot. In this case, the annotated functions are
not limited in the kprobes-related functions, and __kprobes looks
very confusing. (Moreover, actually, most of control-side kprobes
functions like as register_kprobes() are safely probed by kprobes)

Thus, we decide to introduce 'nokprobe' new annotation. We leave
"__kprobes" just for compatibility but it should be replaced or
removed eventually.

New commits must use 'nokprobe' for this purpose.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
---
 include/linux/compiler.h |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 92669cd..173c64e 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -353,8 +353,10 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
 
 /* Ignore/forbid kprobes attach on very low level functions marked by this attribute: */
 #ifdef CONFIG_KPROBES
-# define __kprobes	__attribute__((__section__(".kprobes.text")))
+# define nokprobe	__attribute__((__section__(".kprobes.text")))
 #else
-# define __kprobes
+# define nokprobe
 #endif
+#define __kprobes nokprobe
+
 #endif /* __LINUX_COMPILER_H */