arc: kprobes: Use generic kretprobe trampoline handler (f75dd136) · Commits · 戴 / test

arch/arc/kernel/kprobes.c

+2 −52

Original line number	Diff line number	Diff line
		@@ -388,6 +388,7 @@ void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
		{

		ri->ret_addr = (kprobe_opcode_t *) regs->blink;
		ri->fp = NULL;

		/* Replace the return addr with trampoline addr */
		regs->blink = (unsigned long)&kretprobe_trampoline;
		@@ -396,58 +397,7 @@ void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
		static int __kprobes trampoline_probe_handler(struct kprobe *p,
		struct pt_regs *regs)
		{
		struct kretprobe_instance *ri = NULL;
		struct hlist_head *head, empty_rp;
		struct hlist_node *tmp;
		unsigned long flags, orig_ret_address = 0;
		unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline;

		INIT_HLIST_HEAD(&empty_rp);
		kretprobe_hash_lock(current, &head, &flags);

		/*
		* It is possible to have multiple instances associated with a given
		* task either because an multiple functions in the call path
		* have a return probe installed on them, and/or more than one return
		* return probe was registered for a target function.
		*
		* We can handle this because:
		* - instances are always inserted at the head of the list
		* - when multiple return probes are registered for the same
		* function, the first instance's ret_addr will point to the
		* real return address, and all the rest will point to
		* kretprobe_trampoline
		*/
		hlist_for_each_entry_safe(ri, tmp, head, hlist) {
		if (ri->task != current)
		/* another task is sharing our hash bucket */
		continue;

		if (ri->rp && ri->rp->handler)
		ri->rp->handler(ri, regs);

		orig_ret_address = (unsigned long)ri->ret_addr;
		recycle_rp_inst(ri, &empty_rp);

		if (orig_ret_address != trampoline_address) {
		/*
		* This is the real return address. Any other
		* instances associated with this task are for
		* other calls deeper on the call stack
		*/
		break;
		}
		}

		kretprobe_assert(ri, orig_ret_address, trampoline_address);
		regs->ret = orig_ret_address;

		kretprobe_hash_unlock(current, &flags);

		hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
		hlist_del(&ri->hlist);
		kfree(ri);
		}
		regs->ret = __kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL);

		/* By returning a non zero value, we are telling the kprobe handler
		* that we don't want the post_handler to run

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