kprobes, ftrace: Allow probing on some functions

There is no need to prohibit probing on the functions
used for preparation and uprobe only fetch functions.
Those are safely probed because those are not invoked
from kprobe's breakpoint/fault/debug handlers. So there
is no chance to cause recursive exceptions.

Following functions are now removed from the kprobes blacklist:

	update_bitfield_fetch_param
	free_bitfield_fetch_param
	kprobe_register
	FETCH_FUNC_NAME(stack, type) in trace_uprobe.c
	FETCH_FUNC_NAME(memory, type) in trace_uprobe.c
	FETCH_FUNC_NAME(memory, string) in trace_uprobe.c
	FETCH_FUNC_NAME(memory, string_size) in trace_uprobe.c
	FETCH_FUNC_NAME(file_offset, type) in trace_uprobe.c

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20140417081800.26341.56504.stgit@ltc230.yrl.intra.hitachi.co.jp
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kernel/trace/trace_kprobe.c

@@ -1196,9 +1196,8 @@ kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
  * lockless, but we can't race with this __init function.
  */
-static __kprobes
-int kprobe_register(struct ftrace_event_call *event,
-		    enum trace_reg type, void *data)
+static int kprobe_register(struct ftrace_event_call *event,
+			   enum trace_reg type, void *data)
 {
 	struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
 	struct ftrace_event_file *file = data;

kernel/trace/trace_probe.c

@@ -183,7 +183,7 @@ DEFINE_BASIC_FETCH_FUNCS(bitfield)
 #define fetch_bitfield_string		NULL
 #define fetch_bitfield_string_size	NULL
 
-static __kprobes void
+static void
 update_bitfield_fetch_param(struct bitfield_fetch_param *data)
 {
 	/*
@@ -196,7 +196,7 @@ update_bitfield_fetch_param(struct bitfield_fetch_param *data)
 		update_symbol_cache(data->orig.data);
 }
 
-static __kprobes void
+static void
 free_bitfield_fetch_param(struct bitfield_fetch_param *data)
 {
 	/*

kernel/trace/trace_uprobe.c

@@ -108,8 +108,8 @@ static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n)
  * Uprobes-specific fetch functions
  */
 #define DEFINE_FETCH_stack(type)					\
-static __kprobes void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,\
-					  void *offset, void *dest)	\
+static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,		\
+					 void *offset, void *dest)	\
 {									\
 	*(type *)dest = (type)get_user_stack_nth(regs,			\
 					      ((unsigned long)offset)); \
@@ -120,8 +120,8 @@ DEFINE_BASIC_FETCH_FUNCS(stack)
 #define fetch_stack_string_size	NULL
 
 #define DEFINE_FETCH_memory(type)					\
-static __kprobes void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,\
-						void *addr, void *dest) \
+static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,		\
+					  void *addr, void *dest)	\
 {									\
 	type retval;							\
 	void __user *vaddr = (void __force __user *) addr;		\
@@ -136,8 +136,8 @@ DEFINE_BASIC_FETCH_FUNCS(memory)
  * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
  * length and relative data location.
  */
-static __kprobes void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
-						      void *addr, void *dest)
+static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
+					    void *addr, void *dest)
 {
 	long ret;
 	u32 rloc = *(u32 *)dest;
@@ -158,8 +158,8 @@ static __kprobes void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
 	}
 }
 
-static __kprobes void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
-						      void *addr, void *dest)
+static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
+						 void *addr, void *dest)
 {
 	int len;
 	void __user *vaddr = (void __force __user *) addr;
@@ -184,8 +184,8 @@ static unsigned long translate_user_vaddr(void *file_offset)
 }
 
 #define DEFINE_FETCH_file_offset(type)					\
-static __kprobes void FETCH_FUNC_NAME(file_offset, type)(struct pt_regs *regs,\
-					void *offset, void *dest) 	\
+static void FETCH_FUNC_NAME(file_offset, type)(struct pt_regs *regs,	\
+					       void *offset, void *dest)\
 {									\
 	void *vaddr = (void *)translate_user_vaddr(offset);		\
 									\