[S390] add kprobes support. (4ba069b8) · Commits · e / devices / android_kernel_teracube_2e

arch/s390/Kconfig

+14 −0

Original line number	Diff line number	Diff line
		@@ -487,8 +487,22 @@ source "drivers/net/Kconfig"

		source "fs/Kconfig"

		menu "Instrumentation Support"

		source "arch/s390/oprofile/Kconfig"

		config KPROBES
		bool "Kprobes (EXPERIMENTAL)"
		depends on EXPERIMENTAL && MODULES
		help
		Kprobes allows you to trap at almost any kernel address and
		execute a callback function. register_kprobe() establishes
		a probepoint and specifies the callback. Kprobes is useful
		for kernel debugging, non-intrusive instrumentation and testing.
		If in doubt, say "N".

		endmenu

		source "arch/s390/Kconfig.debug"

		source "security/Kconfig"

arch/s390/kernel/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -24,6 +24,7 @@ obj-$(CONFIG_COMPAT) += compat_linux.o compat_signal.o \

		obj-$(CONFIG_VIRT_TIMER) += vtime.o
		obj-$(CONFIG_STACKTRACE) += stacktrace.o
		obj-$(CONFIG_KPROBES) += kprobes.o

		# Kexec part
		S390_KEXEC_OBJS := machine_kexec.o crash.o

arch/s390/kernel/entry.S

+12 −0

Original line number	Diff line number	Diff line
		@@ -505,6 +505,8 @@ pgm_no_vtime2:
		mvc __THREAD_per+__PER_address(4,%r1),__LC_PER_ADDRESS
		mvc __THREAD_per+__PER_access_id(1,%r1),__LC_PER_ACCESS_ID
		oi __TI_flags+3(%r9),_TIF_SINGLE_STEP # set TIF_SINGLE_STEP
		tm SP_PSW+1(%r15),0x01 # kernel per event ?
		bz BASED(kernel_per)
		l %r3,__LC_PGM_ILC # load program interruption code
		la %r8,0x7f
		nr %r8,%r3 # clear per-event-bit and ilc
		@@ -536,6 +538,16 @@ pgm_no_vtime3:
		stosm __SF_EMPTY(%r15),0x03 # reenable interrupts
		b BASED(sysc_do_svc)

		#
		# per was called from kernel, must be kprobes
		#
		kernel_per:
		mvi SP_TRAP+1(%r15),0x28 # set trap indication to pgm check
		la %r2,SP_PTREGS(%r15) # address of register-save area
		l %r1,BASED(.Lhandle_per) # load adr. of per handler
		la %r14,BASED(sysc_leave) # load adr. of system return
		br %r1 # branch to do_single_step

		/*
		* IO interrupt handler routine
		*/

arch/s390/kernel/entry64.S

+12 −0

Original line number	Diff line number	Diff line
		@@ -518,6 +518,8 @@ pgm_no_vtime2:
		#endif
		lg %r9,__LC_THREAD_INFO # load pointer to thread_info struct
		lg %r1,__TI_task(%r9)
		tm SP_PSW+1(%r15),0x01 # kernel per event ?
		jz kernel_per
		mvc __THREAD_per+__PER_atmid(2,%r1),__LC_PER_ATMID
		mvc __THREAD_per+__PER_address(8,%r1),__LC_PER_ADDRESS
		mvc __THREAD_per+__PER_access_id(1,%r1),__LC_PER_ACCESS_ID
		@@ -553,6 +555,16 @@ pgm_no_vtime3:
		stosm __SF_EMPTY(%r15),0x03 # reenable interrupts
		j sysc_do_svc

		#
		# per was called from kernel, must be kprobes
		#
		kernel_per:
		lhi %r0,__LC_PGM_OLD_PSW
		sth %r0,SP_TRAP(%r15) # set trap indication to pgm check
		la %r2,SP_PTREGS(%r15) # address of register-save area
		larl %r14,sysc_leave # load adr. of system ret, no work
		jg do_single_step # branch to do_single_step

		/*
		* IO interrupt handler routine
		*/

arch/s390/kernel/kprobes.c

0 → 100644

+657 −0

Original line number	Diff line number	Diff line
		/*
		* Kernel Probes (KProbes)
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License as published by
		* the Free Software Foundation; either version 2 of the License, or
		* (at your option) any later version.
		*
		* This program is distributed in the hope that it will be useful,
		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*
		* You should have received a copy of the GNU General Public License
		* along with this program; if not, write to the Free Software
		* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
		*
		* Copyright (C) IBM Corporation, 2002, 2006
		*
		* s390 port, used ppc64 as template. Mike Grundy <grundym@us.ibm.com>
		*/

		#include <linux/config.h>
		#include <linux/kprobes.h>
		#include <linux/ptrace.h>
		#include <linux/preempt.h>
		#include <linux/stop_machine.h>
		#include <asm/cacheflush.h>
		#include <asm/kdebug.h>
		#include <asm/sections.h>
		#include <asm/uaccess.h>
		#include <linux/module.h>

		DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
		DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);

		int __kprobes arch_prepare_kprobe(struct kprobe *p)
		{
		/* Make sure the probe isn't going on a difficult instruction */
		if (is_prohibited_opcode((kprobe_opcode_t *) p->addr))
		return -EINVAL;

		if ((unsigned long)p->addr & 0x01) {
		printk("Attempt to register kprobe at an unaligned address\n");
		return -EINVAL;
		}

		/* Use the get_insn_slot() facility for correctness */
		if (!(p->ainsn.insn = get_insn_slot()))
		return -ENOMEM;

		memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));

		get_instruction_type(&p->ainsn);
		p->opcode = *p->addr;
		return 0;
		}

		int __kprobes is_prohibited_opcode(kprobe_opcode_t *instruction)
		{
		switch ((__u8 ) instruction) {
		case 0x0c: /* bassm */
		case 0x0b: /* bsm */
		case 0x83: /* diag */
		case 0x44: /* ex */
		return -EINVAL;
		}
		switch ((__u16 ) instruction) {
		case 0x0101: /* pr */
		case 0xb25a: /* bsa */
		case 0xb240: /* bakr */
		case 0xb258: /* bsg */
		case 0xb218: /* pc */
		case 0xb228: /* pt */
		return -EINVAL;
		}
		return 0;
		}

		void __kprobes get_instruction_type(struct arch_specific_insn *ainsn)
		{
		/* default fixup method */
		ainsn->fixup = FIXUP_PSW_NORMAL;

		/* save r1 operand */
		ainsn->reg = (*ainsn->insn & 0xf0) >> 4;

		/* save the instruction length (pop 5-5) in bytes */
		switch ((__u8 ) (ainsn->insn) >> 4) {
		case 0:
		ainsn->ilen = 2;
		break;
		case 1:
		case 2:
		ainsn->ilen = 4;
		break;
		case 3:
		ainsn->ilen = 6;
		break;
		}

		switch ((__u8 ) ainsn->insn) {
		case 0x05: /* balr */
		case 0x0d: /* basr */
		ainsn->fixup = FIXUP_RETURN_REGISTER;
		/* if r2 = 0, no branch will be taken */
		if ((*ainsn->insn & 0x0f) == 0)
		ainsn->fixup \|= FIXUP_BRANCH_NOT_TAKEN;
		break;
		case 0x06: /* bctr */
		case 0x07: /* bcr */
		ainsn->fixup = FIXUP_BRANCH_NOT_TAKEN;
		break;
		case 0x45: /* bal */
		case 0x4d: /* bas */
		ainsn->fixup = FIXUP_RETURN_REGISTER;
		break;
		case 0x47: /* bc */
		case 0x46: /* bct */
		case 0x86: /* bxh */
		case 0x87: /* bxle */
		ainsn->fixup = FIXUP_BRANCH_NOT_TAKEN;
		break;
		case 0x82: /* lpsw */
		ainsn->fixup = FIXUP_NOT_REQUIRED;
		break;
		case 0xb2: /* lpswe */
		if ((((__u8 ) ainsn->insn) + 1) == 0xb2) {
		ainsn->fixup = FIXUP_NOT_REQUIRED;
		}
		break;
		case 0xa7: /* bras */
		if ((*ainsn->insn & 0x0f) == 0x05) {
		ainsn->fixup \|= FIXUP_RETURN_REGISTER;
		}
		break;
		case 0xc0:
		if ((ainsn->insn & 0x0f) == 0x00 / larl */
		\|\| (ainsn->insn & 0x0f) == 0x05) / brasl */
		ainsn->fixup \|= FIXUP_RETURN_REGISTER;
		break;
		case 0xeb:
		if ((((__u8 ) ainsn->insn) + 5 ) == 0x44 \|\| /* bxhg */
		(((__u8 ) ainsn->insn) + 5) == 0x45) {/* bxleg */
		ainsn->fixup = FIXUP_BRANCH_NOT_TAKEN;
		}
		break;
		case 0xe3: /* bctg */
		if ((((__u8 ) ainsn->insn) + 5) == 0x46) {
		ainsn->fixup = FIXUP_BRANCH_NOT_TAKEN;
		}
		break;
		}
		}

		static int __kprobes swap_instruction(void *aref)
		{
		struct ins_replace_args *args = aref;
		int err = -EFAULT;

		asm volatile(
		"0: mvc 0(2,%2),0(%3)\n"
		"1: la %0,0\n"
		"2:\n"
		EX_TABLE(0b,2b)
		: "+d" (err), "=m" (*args->ptr)
		: "a" (args->ptr), "a" (&args->new), "m" (args->new));
		return err;
		}

		void __kprobes arch_arm_kprobe(struct kprobe *p)
		{
		struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
		unsigned long status = kcb->kprobe_status;
		struct ins_replace_args args;

		args.ptr = p->addr;
		args.old = p->opcode;
		args.new = BREAKPOINT_INSTRUCTION;

		kcb->kprobe_status = KPROBE_SWAP_INST;
		stop_machine_run(swap_instruction, &args, NR_CPUS);
		kcb->kprobe_status = status;
		}

		void __kprobes arch_disarm_kprobe(struct kprobe *p)
		{
		struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
		unsigned long status = kcb->kprobe_status;
		struct ins_replace_args args;

		args.ptr = p->addr;
		args.old = BREAKPOINT_INSTRUCTION;
		args.new = p->opcode;

		kcb->kprobe_status = KPROBE_SWAP_INST;
		stop_machine_run(swap_instruction, &args, NR_CPUS);
		kcb->kprobe_status = status;
		}

		void __kprobes arch_remove_kprobe(struct kprobe *p)
		{
		mutex_lock(&kprobe_mutex);
		free_insn_slot(p->ainsn.insn);
		mutex_unlock(&kprobe_mutex);
		}

		static void __kprobes prepare_singlestep(struct kprobe p, struct pt_regs regs)
		{
		per_cr_bits kprobe_per_regs[1];

		memset(kprobe_per_regs, 0, sizeof(per_cr_bits));
		regs->psw.addr = (unsigned long)p->ainsn.insn \| PSW_ADDR_AMODE;

		/* Set up the per control reg info, will pass to lctl */
		kprobe_per_regs[0].em_instruction_fetch = 1;
		kprobe_per_regs[0].starting_addr = (unsigned long)p->ainsn.insn;
		kprobe_per_regs[0].ending_addr = (unsigned long)p->ainsn.insn + 1;

		/* Set the PER control regs, turns on single step for this address */
		__ctl_load(kprobe_per_regs, 9, 11);
		regs->psw.mask \|= PSW_MASK_PER;
		regs->psw.mask &= ~(PSW_MASK_IO \| PSW_MASK_EXT \| PSW_MASK_MCHECK);
		}

		static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
		{
		kcb->prev_kprobe.kp = kprobe_running();
		kcb->prev_kprobe.status = kcb->kprobe_status;
		kcb->prev_kprobe.kprobe_saved_imask = kcb->kprobe_saved_imask;
		memcpy(kcb->prev_kprobe.kprobe_saved_ctl, kcb->kprobe_saved_ctl,
		sizeof(kcb->kprobe_saved_ctl));
		}

		static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
		{
		__get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
		kcb->kprobe_status = kcb->prev_kprobe.status;
		kcb->kprobe_saved_imask = kcb->prev_kprobe.kprobe_saved_imask;
		memcpy(kcb->kprobe_saved_ctl, kcb->prev_kprobe.kprobe_saved_ctl,
		sizeof(kcb->kprobe_saved_ctl));
		}

		static void __kprobes set_current_kprobe(struct kprobe p, struct pt_regs regs,
		struct kprobe_ctlblk *kcb)
		{
		__get_cpu_var(current_kprobe) = p;
		/* Save the interrupt and per flags */
		kcb->kprobe_saved_imask = regs->psw.mask &
		(PSW_MASK_PER \| PSW_MASK_IO \| PSW_MASK_EXT \| PSW_MASK_MCHECK);
		/* Save the control regs that govern PER */
		__ctl_store(kcb->kprobe_saved_ctl, 9, 11);
		}

		/* Called with kretprobe_lock held */
		void __kprobes arch_prepare_kretprobe(struct kretprobe *rp,
		struct pt_regs *regs)
		{
		struct kretprobe_instance *ri;

		if ((ri = get_free_rp_inst(rp)) != NULL) {
		ri->rp = rp;
		ri->task = current;
		ri->ret_addr = (kprobe_opcode_t *) regs->gprs[14];

		/* Replace the return addr with trampoline addr */
		regs->gprs[14] = (unsigned long)&kretprobe_trampoline;

		add_rp_inst(ri);
		} else {
		rp->nmissed++;
		}
		}

		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;

		/*
		* We don't want to be preempted for the entire
		* duration of kprobe processing
		*/
		preempt_disable();
		kcb = get_kprobe_ctlblk();

		/* Check we're not actually recursing */
		if (kprobe_running()) {
		p = get_kprobe(addr);
		if (p) {
		if (kcb->kprobe_status == KPROBE_HIT_SS &&
		*p->ainsn.insn == BREAKPOINT_INSTRUCTION) {
		regs->psw.mask &= ~PSW_MASK_PER;
		regs->psw.mask \|= kcb->kprobe_saved_imask;
		goto no_kprobe;
		}
		/* 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.
		*/
		save_previous_kprobe(kcb);
		set_current_kprobe(p, regs, kcb);
		kprobes_inc_nmissed_count(p);
		prepare_singlestep(p, regs);
		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) {
		if (*addr != BREAKPOINT_INSTRUCTION) {
		/*
		* The breakpoint instruction was removed right
		* after we hit it. Another cpu has removed
		* either a probepoint or a debugger breakpoint
		* at this address. In either case, no further
		* handling of this interrupt is appropriate.
		*
		*/
		ret = 1;
		}
		/* Not one of ours: let kernel handle it */
		goto no_kprobe;
		}

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

		ss_probe:
		prepare_singlestep(p, regs);
		kcb->kprobe_status = KPROBE_HIT_SS;
		return 1;

		no_kprobe:
		preempt_enable_no_resched();
		return ret;
		}

		/*
		* Function return probe trampoline:
		* - init_kprobes() establishes a probepoint here
		* - When the probed function returns, this probe
		* causes the handlers to fire
		*/
		void __kprobes kretprobe_trampoline_holder(void)
		{
		asm volatile(".global kretprobe_trampoline\n"
		"kretprobe_trampoline: bcr 0,0\n");
		}

		/*
		* Called when the probe at kretprobe trampoline is hit
		*/
		int __kprobes trampoline_probe_handler(struct kprobe p, struct pt_regs regs)
		{
		struct kretprobe_instance *ri = NULL;
		struct hlist_head *head;
		struct hlist_node node, tmp;
		unsigned long flags, orig_ret_address = 0;
		unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline;

		spin_lock_irqsave(&kretprobe_lock, flags);
		head = kretprobe_inst_table_head(current);

		/*
		* 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 then 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, node, 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);

		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;
		}
		}
		BUG_ON(!orig_ret_address \|\| (orig_ret_address == trampoline_address));
		regs->psw.addr = orig_ret_address \| PSW_ADDR_AMODE;

		reset_current_kprobe();
		spin_unlock_irqrestore(&kretprobe_lock, flags);
		preempt_enable_no_resched();

		/*
		* By returning a non-zero value, we are telling
		* kprobe_handler() that we don't want the post_handler
		* to run (and have re-enabled preemption)
		*/
		return 1;
		}

		/*
		* Called after single-stepping. p->addr is the address of the
		* instruction whose first byte has been replaced by the "breakpoint"
		* instruction. To avoid the SMP problems that can occur when we
		* temporarily put back the original opcode to single-step, we
		* single-stepped a copy of the instruction. The address of this
		* copy is p->ainsn.insn.
		*/
		static void __kprobes resume_execution(struct kprobe p, struct pt_regs regs)
		{
		struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();

		regs->psw.addr &= PSW_ADDR_INSN;

		if (p->ainsn.fixup & FIXUP_PSW_NORMAL)
		regs->psw.addr = (unsigned long)p->addr +
		((unsigned long)regs->psw.addr -
		(unsigned long)p->ainsn.insn);

		if (p->ainsn.fixup & FIXUP_BRANCH_NOT_TAKEN)
		if ((unsigned long)regs->psw.addr -
		(unsigned long)p->ainsn.insn == p->ainsn.ilen)
		regs->psw.addr = (unsigned long)p->addr + p->ainsn.ilen;

		if (p->ainsn.fixup & FIXUP_RETURN_REGISTER)
		regs->gprs[p->ainsn.reg] = ((unsigned long)p->addr +
		(regs->gprs[p->ainsn.reg] -
		(unsigned long)p->ainsn.insn))
		\| PSW_ADDR_AMODE;

		regs->psw.addr \|= PSW_ADDR_AMODE;
		/* turn off PER mode */
		regs->psw.mask &= ~PSW_MASK_PER;
		/* Restore the original per control regs */
		__ctl_load(kcb->kprobe_saved_ctl, 9, 11);
		regs->psw.mask \|= kcb->kprobe_saved_imask;
		}

		static int __kprobes post_kprobe_handler(struct pt_regs *regs)
		{
		struct kprobe *cur = kprobe_running();
		struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();

		if (!cur)
		return 0;

		if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
		kcb->kprobe_status = KPROBE_HIT_SSDONE;
		cur->post_handler(cur, regs, 0);
		}

		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:
		preempt_enable_no_resched();

		/*
		* if somebody else is singlestepping across a probe point, psw mask
		* will have PER set, in which case, continue the remaining processing
		* of do_single_step, as if this is not a probe hit.
		*/
		if (regs->psw.mask & PSW_MASK_PER) {
		return 0;
		}

		return 1;
		}

		static int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
		{
		struct kprobe *cur = kprobe_running();
		struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
		const struct exception_table_entry *entry;

		switch(kcb->kprobe_status) {
		case KPROBE_SWAP_INST:
		/* We are here because the instruction replacement failed */
		return 0;
		case KPROBE_HIT_SS:
		case KPROBE_REENTER:
		/*
		* We are here because the instruction being single
		* stepped caused a page fault. We reset the current
		* kprobe and the nip points back to the probe address
		* and allow the page fault handler to continue as a
		* normal page fault.
		*/
		regs->psw.addr = (unsigned long)cur->addr \| PSW_ADDR_AMODE;
		regs->psw.mask &= ~PSW_MASK_PER;
		regs->psw.mask \|= kcb->kprobe_saved_imask;
		if (kcb->kprobe_status == KPROBE_REENTER)
		restore_previous_kprobe(kcb);
		else
		reset_current_kprobe();
		preempt_enable_no_resched();
		break;
		case KPROBE_HIT_ACTIVE:
		case KPROBE_HIT_SSDONE:
		/*
		* We increment the nmissed count for accounting,
		* we can also use npre/npostfault count for accouting
		* these specific fault cases.
		*/
		kprobes_inc_nmissed_count(cur);

		/*
		* We come here because instructions in the pre/post
		* handler caused the page_fault, this could happen
		* if handler tries to access user space by
		* copy_from_user(), get_user() etc. Let the
		* user-specified handler try to fix it first.
		*/
		if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
		return 1;

		/*
		* In case the user-specified fault handler returned
		* zero, try to fix up.
		*/
		entry = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN);
		if (entry) {
		regs->psw.addr = entry->fixup \| PSW_ADDR_AMODE;
		return 1;
		}

		/*
		* fixup_exception() could not handle it,
		* Let do_page_fault() fix it.
		*/
		break;
		default:
		break;
		}
		return 0;
		}

		/*
		* Wrapper routine to for handling exceptions.
		*/
		int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
		unsigned long val, void *data)
		{
		struct die_args args = (struct die_args )data;
		int ret = NOTIFY_DONE;

		switch (val) {
		case DIE_BPT:
		if (kprobe_handler(args->regs))
		ret = NOTIFY_STOP;
		break;
		case DIE_SSTEP:
		if (post_kprobe_handler(args->regs))
		ret = NOTIFY_STOP;
		break;
		case DIE_TRAP:
		case DIE_PAGE_FAULT:
		/* kprobe_running() needs smp_processor_id() */
		preempt_disable();
		if (kprobe_running() &&
		kprobe_fault_handler(args->regs, args->trapnr))
		ret = NOTIFY_STOP;
		preempt_enable();
		break;
		default:
		break;
		}
		return ret;
		}

		int __kprobes setjmp_pre_handler(struct kprobe p, struct pt_regs regs)
		{
		struct jprobe *jp = container_of(p, struct jprobe, kp);
		unsigned long addr;
		struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();

		memcpy(&kcb->jprobe_saved_regs, regs, sizeof(struct pt_regs));

		/* setup return addr to the jprobe handler routine */
		regs->psw.addr = (unsigned long)(jp->entry) \| PSW_ADDR_AMODE;

		/* r14 is the function return address */
		kcb->jprobe_saved_r14 = (unsigned long)regs->gprs[14];
		/* r15 is the stack pointer */
		kcb->jprobe_saved_r15 = (unsigned long)regs->gprs[15];
		addr = (unsigned long)kcb->jprobe_saved_r15;

		memcpy(kcb->jprobes_stack, (kprobe_opcode_t *) addr,
		MIN_STACK_SIZE(addr));
		return 1;
		}

		void __kprobes jprobe_return(void)
		{
		asm volatile(".word 0x0002");
		}

		void __kprobes jprobe_return_end(void)
		{
		asm volatile("bcr 0,0");
		}

		int __kprobes longjmp_break_handler(struct kprobe p, struct pt_regs regs)
		{
		struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
		unsigned long stack_addr = (unsigned long)(kcb->jprobe_saved_r15);

		/* Put the regs back */
		memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs));
		/* put the stack back */
		memcpy((kprobe_opcode_t *) stack_addr, kcb->jprobes_stack,
		MIN_STACK_SIZE(stack_addr));
		preempt_enable_no_resched();
		return 1;
		}

		static struct kprobe trampoline_p = {
		.addr = (kprobe_opcode_t *) & kretprobe_trampoline,
		.pre_handler = trampoline_probe_handler
		};

		int __init arch_init_kprobes(void)
		{
		return register_kprobe(&trampoline_p);
		}