arch/ia64/kernel/kprobes.c - maze/linux - Git at Google

 /*
  *  Kernel Probes (KProbes)
  *  arch/ia64/kernel/kprobes.c
  *
  * 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, 2004
  * Copyright (C) Intel Corporation, 2005
  *
  * 2005-Apr     Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy
  *              <anil.s.keshavamurthy@intel.com> adapted from i386
  */

 #include <linux/config.h>
 #include <linux/kprobes.h>
 #include <linux/ptrace.h>
 #include <linux/spinlock.h>
 #include <linux/string.h>
 #include <linux/slab.h>
 #include <linux/preempt.h>
 #include <linux/moduleloader.h>

 #include <asm/pgtable.h>
 #include <asm/kdebug.h>

 extern void jprobe_inst_return(void);

 /* kprobe_status settings */
 #define KPROBE_HIT_ACTIVE	0x00000001
 #define KPROBE_HIT_SS		0x00000002

 static struct kprobe *current_kprobe;
 static unsigned long kprobe_status;
 static struct pt_regs jprobe_saved_regs;

 enum instruction_type {A, I, M, F, B, L, X, u};
 static enum instruction_type bundle_encoding[32][3] = {
   { M, I, I },				/* 00 */
   { M, I, I },				/* 01 */
   { M, I, I },				/* 02 */
   { M, I, I },				/* 03 */
   { M, L, X },				/* 04 */
   { M, L, X },				/* 05 */
   { u, u, u },  			/* 06 */
   { u, u, u },  			/* 07 */
   { M, M, I },				/* 08 */
   { M, M, I },				/* 09 */
   { M, M, I },				/* 0A */
   { M, M, I },				/* 0B */
   { M, F, I },				/* 0C */
   { M, F, I },				/* 0D */
   { M, M, F },				/* 0E */
   { M, M, F },				/* 0F */
   { M, I, B },				/* 10 */
   { M, I, B },				/* 11 */
   { M, B, B },				/* 12 */
   { M, B, B },				/* 13 */
   { u, u, u },  			/* 14 */
   { u, u, u },  			/* 15 */
   { B, B, B },				/* 16 */
   { B, B, B },				/* 17 */
   { M, M, B },				/* 18 */
   { M, M, B },				/* 19 */
   { u, u, u },  			/* 1A */
   { u, u, u },  			/* 1B */
   { M, F, B },				/* 1C */
   { M, F, B },				/* 1D */
   { u, u, u },  			/* 1E */
   { u, u, u },  			/* 1F */
 };

 /*
  * In this function we check to see if the instruction
  * is IP relative instruction and update the kprobe
  * inst flag accordingly
  */
 static void update_kprobe_inst_flag(uint template, uint  slot, uint major_opcode,
 	unsigned long kprobe_inst, struct kprobe *p)
 {
 	p->ainsn.inst_flag = 0;
 	p->ainsn.target_br_reg = 0;

 	if (bundle_encoding[template][slot] == B) {
 		switch (major_opcode) {
 		  case INDIRECT_CALL_OPCODE:
 	 		p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
  			p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
  			break;
 		  case IP_RELATIVE_PREDICT_OPCODE:
 		  case IP_RELATIVE_BRANCH_OPCODE:
 			p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
  			break;
 		  case IP_RELATIVE_CALL_OPCODE:
  			p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
  			p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
  			p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
  			break;
 		}
  	} else if (bundle_encoding[template][slot] == X) {
 		switch (major_opcode) {
 		  case LONG_CALL_OPCODE:
 			p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
 			p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
 		  break;
 		}
 	}
 	return;
 }

 /*
  * In this function we override the bundle with
  * the break instruction at the given slot.
  */
 static void prepare_break_inst(uint template, uint  slot, uint major_opcode,
 	unsigned long kprobe_inst, struct kprobe *p)
 {
 	unsigned long break_inst = BREAK_INST;
 	bundle_t *bundle = &p->ainsn.insn.bundle;

 	/*
 	 * Copy the original kprobe_inst qualifying predicate(qp)
 	 * to the break instruction
 	 */
 	break_inst |= (0x3f & kprobe_inst);

 	switch (slot) {
 	  case 0:
 		bundle->quad0.slot0 = break_inst;
 		break;
 	  case 1:
 		bundle->quad0.slot1_p0 = break_inst;
 		bundle->quad1.slot1_p1 = break_inst >> (64-46);
 		break;
 	  case 2:
 		bundle->quad1.slot2 = break_inst;
 		break;
 	}

 	/*
 	 * Update the instruction flag, so that we can
 	 * emulate the instruction properly after we
 	 * single step on original instruction
 	 */
 	update_kprobe_inst_flag(template, slot, major_opcode, kprobe_inst, p);
 }

 static inline void get_kprobe_inst(bundle_t *bundle, uint slot,
 	       	unsigned long *kprobe_inst, uint *major_opcode)
 {
 	unsigned long kprobe_inst_p0, kprobe_inst_p1;
 	unsigned int template;

 	template = bundle->quad0.template;

 	switch (slot) {
 	  case 0:
  		*major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT);
  		*kprobe_inst = bundle->quad0.slot0;
 		break;
 	  case 1:
  		*major_opcode = (bundle->quad1.slot1_p1 >> SLOT1_p1_OPCODE_SHIFT);
   		kprobe_inst_p0 = bundle->quad0.slot1_p0;
   		kprobe_inst_p1 = bundle->quad1.slot1_p1;
   		*kprobe_inst = kprobe_inst_p0 | (kprobe_inst_p1 << (64-46));
 		break;
 	  case 2:
  		*major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT);
  		*kprobe_inst = bundle->quad1.slot2;
 		break;
 	}
 }

 static int valid_kprobe_addr(int template, int slot, unsigned long addr)
 {
 	if ((slot > 2) || ((bundle_encoding[template][1] == L) && slot > 1)) {
 		printk(KERN_WARNING "Attempting to insert unaligned kprobe at 0x%lx\n",
 				addr);
 		return -EINVAL;
 	}
 	return 0;
 }

 int arch_prepare_kprobe(struct kprobe *p)
 {
 	unsigned long addr = (unsigned long) p->addr;
 	unsigned long *kprobe_addr = (unsigned long *)(addr & ~0xFULL);
 	unsigned long kprobe_inst=0;
 	unsigned int slot = addr & 0xf, template, major_opcode = 0;
 	bundle_t *bundle = &p->ainsn.insn.bundle;

 	memcpy(&p->opcode.bundle, kprobe_addr, sizeof(bundle_t));
 	memcpy(&p->ainsn.insn.bundle, kprobe_addr, sizeof(bundle_t));

  	template = bundle->quad0.template;

 	if(valid_kprobe_addr(template, slot, addr))
 		return -EINVAL;

 	/* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
  	if (slot == 1 && bundle_encoding[template][1] == L)
   		slot++;

 	/* Get kprobe_inst and major_opcode from the bundle */
 	get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);

 	prepare_break_inst(template, slot, major_opcode, kprobe_inst, p);

 	return 0;
 }

 void arch_arm_kprobe(struct kprobe *p)
 {
 	unsigned long addr = (unsigned long)p->addr;
 	unsigned long arm_addr = addr & ~0xFULL;

 	memcpy((char *)arm_addr, &p->ainsn.insn.bundle, sizeof(bundle_t));
 	flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t));
 }

 void arch_disarm_kprobe(struct kprobe *p)
 {
 	unsigned long addr = (unsigned long)p->addr;
 	unsigned long arm_addr = addr & ~0xFULL;

 	/* p->opcode contains the original unaltered bundle */
 	memcpy((char *) arm_addr, (char *) &p->opcode.bundle, sizeof(bundle_t));
 	flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t));
 }

 void arch_remove_kprobe(struct kprobe *p)
 {
 }

 /*
  * We are resuming execution after a single step fault, so the pt_regs
  * structure reflects the register state after we executed the instruction
  * located in the kprobe (p->ainsn.insn.bundle).  We still need to adjust
  * the ip to point back to the original stack address. To set the IP address
  * to original stack address, handle the case where we need to fixup the
  * relative IP address and/or fixup branch register.
  */
 static void resume_execution(struct kprobe *p, struct pt_regs *regs)
 {
   	unsigned long bundle_addr = ((unsigned long) (&p->opcode.bundle)) & ~0xFULL;
   	unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL;
  	unsigned long template;
  	int slot = ((unsigned long)p->addr & 0xf);

 	template = p->opcode.bundle.quad0.template;

  	if (slot == 1 && bundle_encoding[template][1] == L)
  		slot = 2;

 	if (p->ainsn.inst_flag) {

 		if (p->ainsn.inst_flag & INST_FLAG_FIX_RELATIVE_IP_ADDR) {
 			/* Fix relative IP address */
  			regs->cr_iip = (regs->cr_iip - bundle_addr) + resume_addr;
 		}

 		if (p->ainsn.inst_flag & INST_FLAG_FIX_BRANCH_REG) {
 		/*
 		 * Fix target branch register, software convention is
 		 * to use either b0 or b6 or b7, so just checking
 		 * only those registers
 		 */
 			switch (p->ainsn.target_br_reg) {
 			case 0:
 				if ((regs->b0 == bundle_addr) ||
 					(regs->b0 == bundle_addr + 0x10)) {
 					regs->b0 = (regs->b0 - bundle_addr) +
 						resume_addr;
 				}
 				break;
 			case 6:
 				if ((regs->b6 == bundle_addr) ||
 					(regs->b6 == bundle_addr + 0x10)) {
 					regs->b6 = (regs->b6 - bundle_addr) +
 						resume_addr;
 				}
 				break;
 			case 7:
 				if ((regs->b7 == bundle_addr) ||
 					(regs->b7 == bundle_addr + 0x10)) {
 					regs->b7 = (regs->b7 - bundle_addr) +
 						resume_addr;
 				}
 				break;
 			} /* end switch */
 		}
 		goto turn_ss_off;
 	}

 	if (slot == 2) {
  		if (regs->cr_iip == bundle_addr + 0x10) {
  			regs->cr_iip = resume_addr + 0x10;
  		}
  	} else {
  		if (regs->cr_iip == bundle_addr) {
  			regs->cr_iip = resume_addr;
  		}
 	}

 turn_ss_off:
   	/* Turn off Single Step bit */
   	ia64_psr(regs)->ss = 0;
 }

 static void prepare_ss(struct kprobe *p, struct pt_regs *regs)
 {
 	unsigned long bundle_addr = (unsigned long) &p->opcode.bundle;
 	unsigned long slot = (unsigned long)p->addr & 0xf;

 	/* Update instruction pointer (IIP) and slot number (IPSR.ri) */
 	regs->cr_iip = bundle_addr & ~0xFULL;

 	if (slot > 2)
 		slot = 0;

 	ia64_psr(regs)->ri = slot;

 	/* turn on single stepping */
 	ia64_psr(regs)->ss = 1;
 }

 static int pre_kprobes_handler(struct pt_regs *regs)
 {
 	struct kprobe *p;
 	int ret = 0;
 	kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);

 	preempt_disable();

 	/* Handle recursion cases */
 	if (kprobe_running()) {
 		p = get_kprobe(addr);
 		if (p) {
 			if (kprobe_status == KPROBE_HIT_SS) {
 				unlock_kprobes();
 				goto no_kprobe;
 			}
 			arch_disarm_kprobe(p);
 			ret = 1;
 		} else {
 			/*
 			 * jprobe instrumented function just completed
 			 */
 			p = current_kprobe;
 			if (p->break_handler && p->break_handler(p, regs)) {
 				goto ss_probe;
 			}
 		}
 	}

 	lock_kprobes();
 	p = get_kprobe(addr);
 	if (!p) {
 		unlock_kprobes();
 		goto no_kprobe;
 	}

 	kprobe_status = KPROBE_HIT_ACTIVE;
 	current_kprobe = p;

 	if (p->pre_handler && p->pre_handler(p, regs))
 		/*
 		 * Our pre-handler is specifically requesting that we just
 		 * do a return.  This is handling the case where the
 		 * pre-handler is really our special jprobe pre-handler.
 		 */
 		return 1;

 ss_probe:
 	prepare_ss(p, regs);
 	kprobe_status = KPROBE_HIT_SS;
 	return 1;

 no_kprobe:
 	preempt_enable_no_resched();
 	return ret;
 }

 static int post_kprobes_handler(struct pt_regs *regs)
 {
 	if (!kprobe_running())
 		return 0;

 	if (current_kprobe->post_handler)
 		current_kprobe->post_handler(current_kprobe, regs, 0);

 	resume_execution(current_kprobe, regs);

 	unlock_kprobes();
 	preempt_enable_no_resched();
 	return 1;
 }

 static int kprobes_fault_handler(struct pt_regs *regs, int trapnr)
 {
 	if (!kprobe_running())
 		return 0;

 	if (current_kprobe->fault_handler &&
 	    current_kprobe->fault_handler(current_kprobe, regs, trapnr))
 		return 1;

 	if (kprobe_status & KPROBE_HIT_SS) {
 		resume_execution(current_kprobe, regs);
 		unlock_kprobes();
 		preempt_enable_no_resched();
 	}

 	return 0;
 }

 int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val,
 			     void *data)
 {
 	struct die_args *args = (struct die_args *)data;
 	switch(val) {
 	case DIE_BREAK:
 		if (pre_kprobes_handler(args->regs))
 			return NOTIFY_STOP;
 		break;
 	case DIE_SS:
 		if (post_kprobes_handler(args->regs))
 			return NOTIFY_STOP;
 		break;
 	case DIE_PAGE_FAULT:
 		if (kprobes_fault_handler(args->regs, args->trapnr))
 			return NOTIFY_STOP;
 	default:
 		break;
 	}
 	return NOTIFY_DONE;
 }

 int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
 {
 	struct jprobe *jp = container_of(p, struct jprobe, kp);
 	unsigned long addr = ((struct fnptr *)(jp->entry))->ip;

 	/* save architectural state */
 	jprobe_saved_regs = *regs;

 	/* after rfi, execute the jprobe instrumented function */
 	regs->cr_iip = addr & ~0xFULL;
 	ia64_psr(regs)->ri = addr & 0xf;
 	regs->r1 = ((struct fnptr *)(jp->entry))->gp;

 	/*
 	 * fix the return address to our jprobe_inst_return() function
 	 * in the jprobes.S file
 	 */
  	regs->b0 = ((struct fnptr *)(jprobe_inst_return))->ip;

 	return 1;
 }

 int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
 {
 	*regs = jprobe_saved_regs;
 	return 1;
 }
	/*
	* Kernel Probes (KProbes)
	* arch/ia64/kernel/kprobes.c
	*
	* 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, 2004
	* Copyright (C) Intel Corporation, 2005
	*
	* 2005-Apr Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy
	* <anil.s.keshavamurthy@intel.com> adapted from i386
	*/

	#include <linux/config.h>
	#include <linux/kprobes.h>
	#include <linux/ptrace.h>
	#include <linux/spinlock.h>
	#include <linux/string.h>
	#include <linux/slab.h>
	#include <linux/preempt.h>
	#include <linux/moduleloader.h>

	#include <asm/pgtable.h>
	#include <asm/kdebug.h>

	extern void jprobe_inst_return(void);

	/* kprobe_status settings */
	#define KPROBE_HIT_ACTIVE 0x00000001
	#define KPROBE_HIT_SS 0x00000002

	static struct kprobe *current_kprobe;
	static unsigned long kprobe_status;
	static struct pt_regs jprobe_saved_regs;

	enum instruction_type {A, I, M, F, B, L, X, u};
	static enum instruction_type bundle_encoding[32][3] = {
	{ M, I, I }, /* 00 */
	{ M, I, I }, /* 01 */
	{ M, I, I }, /* 02 */
	{ M, I, I }, /* 03 */
	{ M, L, X }, /* 04 */
	{ M, L, X }, /* 05 */
	{ u, u, u }, /* 06 */
	{ u, u, u }, /* 07 */
	{ M, M, I }, /* 08 */
	{ M, M, I }, /* 09 */
	{ M, M, I }, /* 0A */
	{ M, M, I }, /* 0B */
	{ M, F, I }, /* 0C */
	{ M, F, I }, /* 0D */
	{ M, M, F }, /* 0E */
	{ M, M, F }, /* 0F */
	{ M, I, B }, /* 10 */
	{ M, I, B }, /* 11 */
	{ M, B, B }, /* 12 */
	{ M, B, B }, /* 13 */
	{ u, u, u }, /* 14 */
	{ u, u, u }, /* 15 */
	{ B, B, B }, /* 16 */
	{ B, B, B }, /* 17 */
	{ M, M, B }, /* 18 */
	{ M, M, B }, /* 19 */
	{ u, u, u }, /* 1A */
	{ u, u, u }, /* 1B */
	{ M, F, B }, /* 1C */
	{ M, F, B }, /* 1D */
	{ u, u, u }, /* 1E */
	{ u, u, u }, /* 1F */
	};

	/*
	* In this function we check to see if the instruction
	* is IP relative instruction and update the kprobe
	* inst flag accordingly
	*/
	static void update_kprobe_inst_flag(uint template, uint slot, uint major_opcode,
	unsigned long kprobe_inst, struct kprobe *p)
	{
	p->ainsn.inst_flag = 0;
	p->ainsn.target_br_reg = 0;

	if (bundle_encoding[template][slot] == B) {
	switch (major_opcode) {
	case INDIRECT_CALL_OPCODE:
	p->ainsn.inst_flag \|= INST_FLAG_FIX_BRANCH_REG;
	p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
	break;
	case IP_RELATIVE_PREDICT_OPCODE:
	case IP_RELATIVE_BRANCH_OPCODE:
	p->ainsn.inst_flag \|= INST_FLAG_FIX_RELATIVE_IP_ADDR;
	break;
	case IP_RELATIVE_CALL_OPCODE:
	p->ainsn.inst_flag \|= INST_FLAG_FIX_RELATIVE_IP_ADDR;
	p->ainsn.inst_flag \|= INST_FLAG_FIX_BRANCH_REG;
	p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
	break;
	}
	} else if (bundle_encoding[template][slot] == X) {
	switch (major_opcode) {
	case LONG_CALL_OPCODE:
	p->ainsn.inst_flag \|= INST_FLAG_FIX_BRANCH_REG;
	p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
	break;
	}
	}
	return;
	}

	/*
	* In this function we override the bundle with
	* the break instruction at the given slot.
	*/
	static void prepare_break_inst(uint template, uint slot, uint major_opcode,
	unsigned long kprobe_inst, struct kprobe *p)
	{
	unsigned long break_inst = BREAK_INST;
	bundle_t *bundle = &p->ainsn.insn.bundle;

	/*
	* Copy the original kprobe_inst qualifying predicate(qp)
	* to the break instruction
	*/
	break_inst \|= (0x3f & kprobe_inst);

	switch (slot) {
	case 0:
	bundle->quad0.slot0 = break_inst;
	break;
	case 1:
	bundle->quad0.slot1_p0 = break_inst;
	bundle->quad1.slot1_p1 = break_inst >> (64-46);
	break;
	case 2:
	bundle->quad1.slot2 = break_inst;
	break;
	}

	/*
	* Update the instruction flag, so that we can
	* emulate the instruction properly after we
	* single step on original instruction
	*/
	update_kprobe_inst_flag(template, slot, major_opcode, kprobe_inst, p);
	}

	static inline void get_kprobe_inst(bundle_t *bundle, uint slot,
	unsigned long kprobe_inst, uint major_opcode)
	{
	unsigned long kprobe_inst_p0, kprobe_inst_p1;
	unsigned int template;

	template = bundle->quad0.template;

	switch (slot) {
	case 0:
	*major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT);
	*kprobe_inst = bundle->quad0.slot0;
	break;
	case 1:
	*major_opcode = (bundle->quad1.slot1_p1 >> SLOT1_p1_OPCODE_SHIFT);
	kprobe_inst_p0 = bundle->quad0.slot1_p0;
	kprobe_inst_p1 = bundle->quad1.slot1_p1;
	*kprobe_inst = kprobe_inst_p0 \| (kprobe_inst_p1 << (64-46));
	break;
	case 2:
	*major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT);
	*kprobe_inst = bundle->quad1.slot2;
	break;
	}
	}

	static int valid_kprobe_addr(int template, int slot, unsigned long addr)
	{
	if ((slot > 2) \|\| ((bundle_encoding[template][1] == L) && slot > 1)) {
	printk(KERN_WARNING "Attempting to insert unaligned kprobe at 0x%lx\n",
	addr);
	return -EINVAL;
	}
	return 0;
	}

	int arch_prepare_kprobe(struct kprobe *p)
	{
	unsigned long addr = (unsigned long) p->addr;
	unsigned long kprobe_addr = (unsigned long )(addr & ~0xFULL);
	unsigned long kprobe_inst=0;
	unsigned int slot = addr & 0xf, template, major_opcode = 0;
	bundle_t *bundle = &p->ainsn.insn.bundle;

	memcpy(&p->opcode.bundle, kprobe_addr, sizeof(bundle_t));
	memcpy(&p->ainsn.insn.bundle, kprobe_addr, sizeof(bundle_t));

	template = bundle->quad0.template;

	if(valid_kprobe_addr(template, slot, addr))
	return -EINVAL;

	/* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
	if (slot == 1 && bundle_encoding[template][1] == L)
	slot++;

	/* Get kprobe_inst and major_opcode from the bundle */
	get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);

	prepare_break_inst(template, slot, major_opcode, kprobe_inst, p);

	return 0;
	}

	void arch_arm_kprobe(struct kprobe *p)
	{
	unsigned long addr = (unsigned long)p->addr;
	unsigned long arm_addr = addr & ~0xFULL;

	memcpy((char *)arm_addr, &p->ainsn.insn.bundle, sizeof(bundle_t));
	flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t));
	}

	void arch_disarm_kprobe(struct kprobe *p)
	{
	unsigned long addr = (unsigned long)p->addr;
	unsigned long arm_addr = addr & ~0xFULL;

	/* p->opcode contains the original unaltered bundle */
	memcpy((char ) arm_addr, (char ) &p->opcode.bundle, sizeof(bundle_t));
	flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t));
	}

	void arch_remove_kprobe(struct kprobe *p)
	{
	}

	/*
	* We are resuming execution after a single step fault, so the pt_regs
	* structure reflects the register state after we executed the instruction
	* located in the kprobe (p->ainsn.insn.bundle). We still need to adjust
	* the ip to point back to the original stack address. To set the IP address
	* to original stack address, handle the case where we need to fixup the
	* relative IP address and/or fixup branch register.
	*/
	static void resume_execution(struct kprobe p, struct pt_regs regs)
	{
	unsigned long bundle_addr = ((unsigned long) (&p->opcode.bundle)) & ~0xFULL;
	unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL;
	unsigned long template;
	int slot = ((unsigned long)p->addr & 0xf);

	template = p->opcode.bundle.quad0.template;

	if (slot == 1 && bundle_encoding[template][1] == L)
	slot = 2;

	if (p->ainsn.inst_flag) {

	if (p->ainsn.inst_flag & INST_FLAG_FIX_RELATIVE_IP_ADDR) {
	/* Fix relative IP address */
	regs->cr_iip = (regs->cr_iip - bundle_addr) + resume_addr;
	}

	if (p->ainsn.inst_flag & INST_FLAG_FIX_BRANCH_REG) {
	/*
	* Fix target branch register, software convention is
	* to use either b0 or b6 or b7, so just checking
	* only those registers
	*/
	switch (p->ainsn.target_br_reg) {
	case 0:
	if ((regs->b0 == bundle_addr) \|\|
	(regs->b0 == bundle_addr + 0x10)) {
	regs->b0 = (regs->b0 - bundle_addr) +
	resume_addr;
	}
	break;
	case 6:
	if ((regs->b6 == bundle_addr) \|\|
	(regs->b6 == bundle_addr + 0x10)) {
	regs->b6 = (regs->b6 - bundle_addr) +
	resume_addr;
	}
	break;
	case 7:
	if ((regs->b7 == bundle_addr) \|\|
	(regs->b7 == bundle_addr + 0x10)) {
	regs->b7 = (regs->b7 - bundle_addr) +
	resume_addr;
	}
	break;
	} /* end switch */
	}
	goto turn_ss_off;
	}

	if (slot == 2) {
	if (regs->cr_iip == bundle_addr + 0x10) {
	regs->cr_iip = resume_addr + 0x10;
	}
	} else {
	if (regs->cr_iip == bundle_addr) {
	regs->cr_iip = resume_addr;
	}
	}

	turn_ss_off:
	/* Turn off Single Step bit */
	ia64_psr(regs)->ss = 0;
	}

	static void prepare_ss(struct kprobe p, struct pt_regs regs)
	{
	unsigned long bundle_addr = (unsigned long) &p->opcode.bundle;
	unsigned long slot = (unsigned long)p->addr & 0xf;

	/* Update instruction pointer (IIP) and slot number (IPSR.ri) */
	regs->cr_iip = bundle_addr & ~0xFULL;

	if (slot > 2)
	slot = 0;

	ia64_psr(regs)->ri = slot;

	/* turn on single stepping */
	ia64_psr(regs)->ss = 1;
	}

	static int pre_kprobes_handler(struct pt_regs *regs)
	{
	struct kprobe *p;
	int ret = 0;
	kprobe_opcode_t addr = (kprobe_opcode_t )instruction_pointer(regs);

	preempt_disable();

	/* Handle recursion cases */
	if (kprobe_running()) {
	p = get_kprobe(addr);
	if (p) {
	if (kprobe_status == KPROBE_HIT_SS) {
	unlock_kprobes();
	goto no_kprobe;
	}
	arch_disarm_kprobe(p);
	ret = 1;
	} else {
	/*
	* jprobe instrumented function just completed
	*/
	p = current_kprobe;
	if (p->break_handler && p->break_handler(p, regs)) {
	goto ss_probe;
	}
	}
	}

	lock_kprobes();
	p = get_kprobe(addr);
	if (!p) {
	unlock_kprobes();
	goto no_kprobe;
	}

	kprobe_status = KPROBE_HIT_ACTIVE;
	current_kprobe = p;

	if (p->pre_handler && p->pre_handler(p, regs))
	/*
	* Our pre-handler is specifically requesting that we just
	* do a return. This is handling the case where the
	* pre-handler is really our special jprobe pre-handler.
	*/
	return 1;

	ss_probe:
	prepare_ss(p, regs);
	kprobe_status = KPROBE_HIT_SS;
	return 1;

	no_kprobe:
	preempt_enable_no_resched();
	return ret;
	}

	static int post_kprobes_handler(struct pt_regs *regs)
	{
	if (!kprobe_running())
	return 0;

	if (current_kprobe->post_handler)
	current_kprobe->post_handler(current_kprobe, regs, 0);

	resume_execution(current_kprobe, regs);

	unlock_kprobes();
	preempt_enable_no_resched();
	return 1;
	}

	static int kprobes_fault_handler(struct pt_regs *regs, int trapnr)
	{
	if (!kprobe_running())
	return 0;

	if (current_kprobe->fault_handler &&
	current_kprobe->fault_handler(current_kprobe, regs, trapnr))
	return 1;

	if (kprobe_status & KPROBE_HIT_SS) {
	resume_execution(current_kprobe, regs);
	unlock_kprobes();
	preempt_enable_no_resched();
	}

	return 0;
	}

	int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val,
	void *data)
	{
	struct die_args args = (struct die_args )data;
	switch(val) {
	case DIE_BREAK:
	if (pre_kprobes_handler(args->regs))
	return NOTIFY_STOP;
	break;
	case DIE_SS:
	if (post_kprobes_handler(args->regs))
	return NOTIFY_STOP;
	break;
	case DIE_PAGE_FAULT:
	if (kprobes_fault_handler(args->regs, args->trapnr))
	return NOTIFY_STOP;
	default:
	break;
	}
	return NOTIFY_DONE;
	}

	int setjmp_pre_handler(struct kprobe p, struct pt_regs regs)
	{
	struct jprobe *jp = container_of(p, struct jprobe, kp);
	unsigned long addr = ((struct fnptr *)(jp->entry))->ip;

	/* save architectural state */
	jprobe_saved_regs = *regs;

	/* after rfi, execute the jprobe instrumented function */
	regs->cr_iip = addr & ~0xFULL;
	ia64_psr(regs)->ri = addr & 0xf;
	regs->r1 = ((struct fnptr *)(jp->entry))->gp;

	/*
	* fix the return address to our jprobe_inst_return() function
	* in the jprobes.S file
	*/
	regs->b0 = ((struct fnptr *)(jprobe_inst_return))->ip;

	return 1;
	}

	int longjmp_break_handler(struct kprobe p, struct pt_regs regs)
	{
	*regs = jprobe_saved_regs;
	return 1;
	}