[S390] kprobes: activation and deactivation (b9599798) · Commits · 戴 / test

arch/s390/kernel/kprobes.c

+27 −32

Original line number	Diff line number	Diff line
		@@ -214,25 +214,29 @@ static void __kprobes disable_singlestep(struct kprobe_ctlblk *kcb,
		regs->psw.addr = ip \| PSW_ADDR_AMODE;
		}


		static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
		/*
		* Activate a kprobe by storing its pointer to current_kprobe. The
		* previous kprobe is stored in kcb->prev_kprobe. A stack of up to
		* two kprobes can be active, see KPROBE_REENTER.
		*/
		static void __kprobes push_kprobe(struct kprobe_ctlblk kcb, struct kprobe p)
		{
		kcb->prev_kprobe.kp = kprobe_running();
		kcb->prev_kprobe.kp = __get_cpu_var(current_kprobe);
		kcb->prev_kprobe.status = kcb->kprobe_status;
		__get_cpu_var(current_kprobe) = p;
		}

		static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
		/*
		* Deactivate a kprobe by backing up to the previous state. If the
		* current state is KPROBE_REENTER prev_kprobe.kp will be non-NULL,
		* for any other state prev_kprobe.kp will be NULL.
		*/
		static void __kprobes pop_kprobe(struct kprobe_ctlblk *kcb)
		{
		__get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
		kcb->kprobe_status = kcb->prev_kprobe.status;
		}

		static void __kprobes set_current_kprobe(struct kprobe p, struct pt_regs regs,
		struct kprobe_ctlblk *kcb)
		{
		__get_cpu_var(current_kprobe) = p;
		}

		void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
		struct pt_regs *regs)
		{
		@@ -261,14 +265,16 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
		if (kprobe_running()) {
		p = get_kprobe(addr);
		if (p) {
		/* We have reentered the kprobe_handler(), since
		* another probe was hit while within the handler.
		* We here save the original kprobes variables and
		* just single step on the instruction of the new probe
		* without calling any user handlers.
		/*
		* We have hit a kprobe while another is still
		* active. This can happen in the pre and post
		* handler. Single step the instruction of the
		* new probe but do not call any handler function
		* of this secondary kprobe.
		* push_kprobe and pop_kprobe saves and restores
		* the currently active kprobe.
		*/
		save_previous_kprobe(kcb);
		set_current_kprobe(p, regs, kcb);
		push_kprobe(kcb, p);
		kprobes_inc_nmissed_count(p);
		enable_singlestep(kcb, regs,
		(unsigned long) p->ainsn.insn);
		@@ -294,7 +300,7 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
		goto no_kprobe;

		kcb->kprobe_status = KPROBE_HIT_ACTIVE;
		set_current_kprobe(p, regs, kcb);
		push_kprobe(kcb, p);
		if (p->pre_handler && p->pre_handler(p, regs))
		/* handler has already set things up, so skip ss setup */
		return 1;
		@@ -395,7 +401,7 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p,

		regs->psw.addr = orig_ret_address \| PSW_ADDR_AMODE;

		reset_current_kprobe();
		pop_kprobe(get_kprobe_ctlblk());
		kretprobe_hash_unlock(current, &flags);
		preempt_enable_no_resched();

		@@ -457,14 +463,7 @@ static int __kprobes post_kprobe_handler(struct pt_regs *regs)
		}

		resume_execution(cur, regs);

		/Restore back the original saved kprobes variables and continue. /
		if (kcb->kprobe_status == KPROBE_REENTER) {
		restore_previous_kprobe(kcb);
		goto out;
		}
		reset_current_kprobe();
		out:
		pop_kprobe(kcb);
		preempt_enable_no_resched();

		/*
		@@ -499,11 +498,7 @@ static int __kprobes kprobe_trap_handler(struct pt_regs *regs, int trapnr)
		* normal page fault.
		*/
		disable_singlestep(kcb, regs, (unsigned long) cur->addr);
		if (kcb->kprobe_status == KPROBE_REENTER)
		restore_previous_kprobe(kcb);
		else {
		reset_current_kprobe();
		}
		pop_kprobe(kcb);
		preempt_enable_no_resched();
		break;
		case KPROBE_HIT_ACTIVE:

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