Commit cb16330d authored by Masami Hiramatsu (Google)'s avatar Masami Hiramatsu (Google)
Browse files

fprobe: Pass return address to the handlers 

Pass return address as 'ret_ip' to the fprobe entry and return handlers
so that the fprobe user handler can get the reutrn address without
analyzing arch-dependent pt_regs.

Link: https://lore.kernel.org/all/168507467664.913472.11642316698862778600.stgit@mhiramat.roam.corp.google.com/



Signed-off-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
parent 9561de3a

include/linux/fprobe.h

+4 −2
Original line number Diff line number Diff line
@@ -35,9 +35,11 @@ struct fprobe { 
	int			nr_maxactive;



	int (*entry_handler)(struct fprobe *fp, unsigned long entry_ip,

			     struct pt_regs *regs, void *entry_data);

			     unsigned long ret_ip, struct pt_regs *regs,

			     void *entry_data);

	void (*exit_handler)(struct fprobe *fp, unsigned long entry_ip,

			     struct pt_regs *regs, void *entry_data);

			     unsigned long ret_ip, struct pt_regs *regs,

			     void *entry_data);

};



/* This fprobe is soft-disabled. */

include/linux/rethook.h

+1 −1
Original line number Diff line number Diff line
@@ -14,7 +14,7 @@ 


struct rethook_node;



typedef void (*rethook_handler_t) (struct rethook_node *, void *, struct pt_regs *);

typedef void (*rethook_handler_t) (struct rethook_node *, void *, unsigned long, struct pt_regs *);



/**

 * struct rethook - The rethook management data structure.

kernel/kprobes.c

+1 −0
Original line number Diff line number Diff line
@@ -2127,6 +2127,7 @@ static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) 
NOKPROBE_SYMBOL(pre_handler_kretprobe);



static void kretprobe_rethook_handler(struct rethook_node *rh, void *data,

				      unsigned long ret_addr,

				      struct pt_regs *regs)

{

	struct kretprobe *rp = (struct kretprobe *)data;

kernel/trace/bpf_trace.c

+4 −2
Original line number Diff line number Diff line
@@ -2642,7 +2642,8 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link, 


static int

kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip,

			  struct pt_regs *regs, void *data)

			  unsigned long ret_ip, struct pt_regs *regs,

			  void *data)

{

	struct bpf_kprobe_multi_link *link;
@@ -2653,7 +2654,8 @@ kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip, 


static void

kprobe_multi_link_exit_handler(struct fprobe *fp, unsigned long fentry_ip,

			       struct pt_regs *regs, void *data)

			       unsigned long ret_ip, struct pt_regs *regs,

			       void *data)

{

	struct bpf_kprobe_multi_link *link;

kernel/trace/fprobe.c

+3 −3
Original line number Diff line number Diff line
@@ -46,7 +46,7 @@ static inline void __fprobe_handler(unsigned long ip, unsigned long parent_ip, 
	}



	if (fp->entry_handler)

		ret = fp->entry_handler(fp, ip, ftrace_get_regs(fregs), entry_data);

		ret = fp->entry_handler(fp, ip, parent_ip, ftrace_get_regs(fregs), entry_data);



	/* If entry_handler returns !0, nmissed is not counted. */

	if (rh) {
@@ -112,7 +112,7 @@ static void fprobe_kprobe_handler(unsigned long ip, unsigned long parent_ip, 
}



static void fprobe_exit_handler(struct rethook_node *rh, void *data,

				struct pt_regs *regs)

				unsigned long ret_ip, struct pt_regs *regs)

{

	struct fprobe *fp = (struct fprobe *)data;

	struct fprobe_rethook_node *fpr;
@@ -133,7 +133,7 @@ static void fprobe_exit_handler(struct rethook_node *rh, void *data, 
		return;

	}



	fp->exit_handler(fp, fpr->entry_ip, regs,

	fp->exit_handler(fp, fpr->entry_ip, ret_ip, regs,

			 fp->entry_data_size ? (void *)fpr->data : NULL);

	ftrace_test_recursion_unlock(bit);

}