Commit 02afb8d6 authored by Punit Agrawal's avatar Punit Agrawal Committed by Steven Rostedt (VMware)
Browse files

kprobe: Simplify prepare_kprobe() by dropping redundant version 

The function prepare_kprobe() is called during kprobe registration and
is responsible for ensuring any architecture related preparation for
the kprobe is done before returning.

One of two versions of prepare_kprobe() is chosen depending on the
availability of KPROBE_ON_FTRACE in the kernel configuration.

Simplify the code by dropping the version when KPROBE_ON_FTRACE is not
selected - instead relying on kprobe_ftrace() to return false when
KPROBE_ON_FTRACE is not set.

No functional change.

Link: https://lkml.kernel.org/r/163163033696.489837.9264661820279300788.stgit@devnote2



Signed-off-by: default avatarPunit Agrawal <punitagrawal@gmail.com>
Acked-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 5d6de7d7

include/linux/kprobes.h

+5 −0
Original line number Diff line number Diff line
@@ -354,6 +354,11 @@ static inline void wait_for_kprobe_optimizer(void) { } 
extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,

				  struct ftrace_ops *ops, struct ftrace_regs *fregs);

extern int arch_prepare_kprobe_ftrace(struct kprobe *p);

#else

static inline int arch_prepare_kprobe_ftrace(struct kprobe *p)

{

	return -EINVAL;

}

#endif



int arch_check_ftrace_location(struct kprobe *p);

kernel/kprobes.c

+9 −14
Original line number Diff line number Diff line
@@ -1033,15 +1033,6 @@ static struct ftrace_ops kprobe_ipmodify_ops __read_mostly = { 
static int kprobe_ipmodify_enabled;

static int kprobe_ftrace_enabled;



/* Must ensure p->addr is really on ftrace */

static int prepare_kprobe(struct kprobe *p)

{

	if (!kprobe_ftrace(p))

		return arch_prepare_kprobe(p);



	return arch_prepare_kprobe_ftrace(p);

}



/* Caller must lock kprobe_mutex */

static int __arm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,

			       int *cnt)
@@ -1113,11 +1104,6 @@ static int disarm_kprobe_ftrace(struct kprobe *p) 
		ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);

}

#else	/* !CONFIG_KPROBES_ON_FTRACE */

static inline int prepare_kprobe(struct kprobe *p)

{

	return arch_prepare_kprobe(p);

}



static inline int arm_kprobe_ftrace(struct kprobe *p)

{

	return -ENODEV;
@@ -1129,6 +1115,15 @@ static inline int disarm_kprobe_ftrace(struct kprobe *p) 
}

#endif



static int prepare_kprobe(struct kprobe *p)

{

	/* Must ensure p->addr is really on ftrace */

	if (kprobe_ftrace(p))

		return arch_prepare_kprobe_ftrace(p);



	return arch_prepare_kprobe(p);

}



/* Arm a kprobe with text_mutex */

static int arm_kprobe(struct kprobe *kp)

{