[S390] kprobes: restructure handler function (0e917cc3) · Commits · 戴 / test

arch/s390/kernel/kprobes.c

+71 −43

Original line number	Diff line number	Diff line
		@@ -238,25 +238,44 @@ void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
		regs->gprs[14] = (unsigned long)&kretprobe_trampoline;
		}

		static void __kprobes kprobe_reenter_check(struct kprobe_ctlblk *kcb,
		struct kprobe *p)
		{
		switch (kcb->kprobe_status) {
		case KPROBE_HIT_SSDONE:
		case KPROBE_HIT_ACTIVE:
		kprobes_inc_nmissed_count(p);
		break;
		case KPROBE_HIT_SS:
		case KPROBE_REENTER:
		default:
		/*
		* A kprobe on the code path to single step an instruction
		* is a BUG. The code path resides in the .kprobes.text
		* section and is executed with interrupts disabled.
		*/
		printk(KERN_EMERG "Invalid kprobe detected at %p.\n", p->addr);
		dump_kprobe(p);
		BUG();
		}
		}

		static int __kprobes kprobe_handler(struct pt_regs *regs)
		{
		struct kprobe *p;
		int ret = 0;
		unsigned long addr = (unsigned long )
		((regs->psw.addr & PSW_ADDR_INSN) - 2);
		struct kprobe_ctlblk *kcb;
		struct kprobe *p;

		/*
		* We don't want to be preempted for the entire
		* duration of kprobe processing
		* We want to disable preemption for the entire duration of kprobe
		* processing. That includes the calls to the pre/post handlers
		* and single stepping the kprobe instruction.
		*/
		preempt_disable();
		kcb = get_kprobe_ctlblk();
		p = get_kprobe((void *)((regs->psw.addr & PSW_ADDR_INSN) - 2));

		/* Check we're not actually recursing */
		if (kprobe_running()) {
		p = get_kprobe(addr);
		if (p) {
		if (kprobe_running()) {
		/*
		* We have hit a kprobe while another is still
		* active. This can happen in the pre and post
		@@ -266,45 +285,54 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
		* push_kprobe and pop_kprobe saves and restores
		* the currently active kprobe.
		*/
		kprobe_reenter_check(kcb, p);
		push_kprobe(kcb, p);
		kprobes_inc_nmissed_count(p);
		enable_singlestep(kcb, regs,
		(unsigned long) p->ainsn.insn);
		kcb->kprobe_status = KPROBE_REENTER;
		return 1;
		} else {
		p = __get_cpu_var(current_kprobe);
		if (p->break_handler && p->break_handler(p, regs)) {
		goto ss_probe;
		}
		}
		goto no_kprobe;
		}

		p = get_kprobe(addr);
		if (!p)
		/*
		* No kprobe at this address. The fault has not been
		* caused by a kprobe breakpoint. The race of breakpoint
		* vs. kprobe remove does not exist because on s390 we
		* use stop_machine to arm/disarm the breakpoints.
		* If we have no pre-handler or it returned 0, we
		* continue with single stepping. If we have a
		* pre-handler and it returned non-zero, it prepped
		* for calling the break_handler below on re-entry
		* for jprobe processing, so get out doing nothing
		* more here.
		*/
		goto no_kprobe;

		kcb->kprobe_status = KPROBE_HIT_ACTIVE;
		push_kprobe(kcb, p);
		kcb->kprobe_status = KPROBE_HIT_ACTIVE;
		if (p->pre_handler && p->pre_handler(p, regs))
		/* handler has already set things up, so skip ss setup */
		return 1;

		ss_probe:
		kcb->kprobe_status = KPROBE_HIT_SS;
		}
		enable_singlestep(kcb, regs, (unsigned long) p->ainsn.insn);
		return 1;
		} else if (kprobe_running()) {
		p = __get_cpu_var(current_kprobe);
		if (p->break_handler && p->break_handler(p, regs)) {
		/*
		* Continuation after the jprobe completed and
		* caused the jprobe_return trap. The jprobe
		* break_handler "returns" to the original
		* function that still has the kprobe breakpoint
		* installed. We continue with single stepping.
		*/
		kcb->kprobe_status = KPROBE_HIT_SS;
		enable_singlestep(kcb, regs,
		(unsigned long) p->ainsn.insn);
		return 1;

		no_kprobe:
		} /* else:
		* No kprobe at this address and the current kprobe
		* has no break handler (no jprobe!). The kernel just
		* exploded, let the standard trap handler pick up the
		* pieces.
		*/
		} /* else:
		* No kprobe at this address and no active kprobe. The trap has
		* not been caused by a kprobe breakpoint. The race of breakpoint
		* vs. kprobe remove does not exist because on s390 as we use
		* stop_machine to arm/disarm the breakpoints.
		*/
		preempt_enable_no_resched();
		return ret;
		return 0;
		}

		/*

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