[mirror_ubuntu-artful-kernel.git] / arch / ia64 / kernel / kprobes.c

/*
 *  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, *kprobe_prev;
static unsigned long kprobe_status, kprobe_status_prev;
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 check to see if the instruction
 * on which we are inserting kprobe is supported.
 * Returns 0 if supported
 * Returns -EINVAL if unsupported
 */
static int unsupported_inst(uint template, uint  slot, uint major_opcode,
	unsigned long kprobe_inst, struct kprobe *p)
{
	unsigned long addr = (unsigned long)p->addr;

	if (bundle_encoding[template][slot] == I) {
		switch (major_opcode) {
			case 0x0: //I_UNIT_MISC_OPCODE:
			/*
			 * Check for Integer speculation instruction
			 * - Bit 33-35 to be equal to 0x1
			 */
			if (((kprobe_inst >> 33) & 0x7) == 1) {
				printk(KERN_WARNING
					"Kprobes on speculation inst at <0x%lx> not supported\n",
					addr);
				return -EINVAL;
			}

			/*
			 * IP relative mov instruction
			 *  - Bit 27-35 to be equal to 0x30
			 */
			if (((kprobe_inst >> 27) & 0x1FF) == 0x30) {
				printk(KERN_WARNING
					"Kprobes on \"mov r1=ip\" at <0x%lx> not supported\n",
					addr);
				return -EINVAL;

			}
		}
	}
	return 0;
}


/*
 * In this function we check to see if the instruction
 * (qp) cmpx.crel.ctype p1,p2=r2,r3
 * on which we are inserting kprobe is cmp instruction
 * with ctype as unc.
 */
static uint is_cmp_ctype_unc_inst(uint template, uint slot, uint major_opcode,
unsigned long kprobe_inst)
{
	cmp_inst_t cmp_inst;
	uint ctype_unc = 0;

	if (!((bundle_encoding[template][slot] == I) ||
		(bundle_encoding[template][slot] == M)))
		goto out;

	if (!((major_opcode == 0xC) || (major_opcode == 0xD) ||
		(major_opcode == 0xE)))
		goto out;

	cmp_inst.l = kprobe_inst;
	if ((cmp_inst.f.x2 == 0) || (cmp_inst.f.x2 == 1)) {
		/* Integere compare - Register Register (A6 type)*/
		if ((cmp_inst.f.tb == 0) && (cmp_inst.f.ta == 0)
				&&(cmp_inst.f.c == 1))
			ctype_unc = 1;
	} else if ((cmp_inst.f.x2 == 2)||(cmp_inst.f.x2 == 3)) {
		/* Integere compare - Immediate Register (A8 type)*/
		if ((cmp_inst.f.ta == 0) &&(cmp_inst.f.c == 1))
			ctype_unc = 1;
	}
out:
	return ctype_unc;
}

/*
 * 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 iff !is_cmp_ctype_unc_inst
	 * because for cmp instruction with ctype equal to unc,
	 * which is a special instruction always needs to be
	 * executed regradless of qp
	 */
	if (!is_cmp_ctype_unc_inst(template, slot, major_opcode, kprobe_inst))
		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;
}

static inline void save_previous_kprobe(void)
{
	kprobe_prev = current_kprobe;
	kprobe_status_prev = kprobe_status;
}

static inline void restore_previous_kprobe(void)
{
	current_kprobe = kprobe_prev;
	kprobe_status = kprobe_status_prev;
}

static inline void set_current_kprobe(struct kprobe *p)
{
	current_kprobe = p;
}

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);

	if (unsupported_inst(template, slot, major_opcode, kprobe_inst, p))
			return -EINVAL;

	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 die_args *args)
{
	struct kprobe *p;
	int ret = 0;
	struct pt_regs *regs = args->regs;
	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;
			}
			/* We have reentered the pre_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();
			set_current_kprobe(p);
			p->nmissed++;
			prepare_ss(p, regs);
			kprobe_status = KPROBE_REENTER;
			return 1;
		} else if (args->err == __IA64_BREAK_JPROBE) {
			/*
			 * jprobe instrumented function just completed
			 */
			p = current_kprobe;
			if (p->break_handler && p->break_handler(p, regs)) {
				goto ss_probe;
			}
		} else {
			/* Not our break */
			goto no_kprobe;
		}
	}

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

	kprobe_status = KPROBE_HIT_ACTIVE;
	set_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 ((kprobe_status != KPROBE_REENTER) && current_kprobe->post_handler) {
		kprobe_status = KPROBE_HIT_SSDONE;
		current_kprobe->post_handler(current_kprobe, regs, 0);
	}

	resume_execution(current_kprobe, regs);

	/*Restore back the original saved kprobes variables and continue. */
	if (kprobe_status == KPROBE_REENTER) {
		restore_previous_kprobe();
		goto out;
	}

	unlock_kprobes();

out:
	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))
			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;
}
Commit	Line	Data
fd7b231f AK	1	/*
	2	* Kernel Probes (KProbes)
	3	* arch/ia64/kernel/kprobes.c
	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License as published by
	7	* the Free Software Foundation; either version 2 of the License, or
	8	* (at your option) any later version.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program; if not, write to the Free Software
	17	* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
	18	*
	19	* Copyright (C) IBM Corporation, 2002, 2004
	20	* Copyright (C) Intel Corporation, 2005
	21	*
	22	* 2005-Apr Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy
	23	* <anil.s.keshavamurthy@intel.com> adapted from i386
	24	*/
	25
	26	#include <linux/config.h>
	27	#include <linux/kprobes.h>
	28	#include <linux/ptrace.h>
	29	#include <linux/spinlock.h>
	30	#include <linux/string.h>
	31	#include <linux/slab.h>
	32	#include <linux/preempt.h>
	33	#include <linux/moduleloader.h>
	34
	35	#include <asm/pgtable.h>
	36	#include <asm/kdebug.h>
	37
b2761dc2 AK	38	extern void jprobe_inst_return(void);
b2761dc2 AK	39
fd7b231f AK	40	/* kprobe_status settings */
	41	#define KPROBE_HIT_ACTIVE 0x00000001
	42	#define KPROBE_HIT_SS 0x00000002
	43
852caccc AK	44	static struct kprobe current_kprobe, kprobe_prev;
852caccc AK	45	static unsigned long kprobe_status, kprobe_status_prev;
b2761dc2	46	static struct pt_regs jprobe_saved_regs;
fd7b231f AK	47
	48	enum instruction_type {A, I, M, F, B, L, X, u};
	49	static enum instruction_type bundle_encoding[32][3] = {
	50	{ M, I, I }, /* 00 */
	51	{ M, I, I }, /* 01 */
	52	{ M, I, I }, /* 02 */
	53	{ M, I, I }, /* 03 */
	54	{ M, L, X }, /* 04 */
	55	{ M, L, X }, /* 05 */
	56	{ u, u, u }, /* 06 */
	57	{ u, u, u }, /* 07 */
	58	{ M, M, I }, /* 08 */
	59	{ M, M, I }, /* 09 */
	60	{ M, M, I }, /* 0A */
	61	{ M, M, I }, /* 0B */
	62	{ M, F, I }, /* 0C */
	63	{ M, F, I }, /* 0D */
	64	{ M, M, F }, /* 0E */
	65	{ M, M, F }, /* 0F */
	66	{ M, I, B }, /* 10 */
	67	{ M, I, B }, /* 11 */
	68	{ M, B, B }, /* 12 */
	69	{ M, B, B }, /* 13 */
	70	{ u, u, u }, /* 14 */
	71	{ u, u, u }, /* 15 */
	72	{ B, B, B }, /* 16 */
	73	{ B, B, B }, /* 17 */
	74	{ M, M, B }, /* 18 */
	75	{ M, M, B }, /* 19 */
	76	{ u, u, u }, /* 1A */
	77	{ u, u, u }, /* 1B */
	78	{ M, F, B }, /* 1C */
	79	{ M, F, B }, /* 1D */
	80	{ u, u, u }, /* 1E */
	81	{ u, u, u }, /* 1F */
	82	};
	83
a5403183 AK	84	/*
	85	* In this function we check to see if the instruction
	86	* is IP relative instruction and update the kprobe
	87	* inst flag accordingly
	88	*/
	89	static void update_kprobe_inst_flag(uint template, uint slot, uint major_opcode,
	90	unsigned long kprobe_inst, struct kprobe *p)
fd7b231f	91	{
8bc76772 RL	92	p->ainsn.inst_flag = 0;
8bc76772 RL	93	p->ainsn.target_br_reg = 0;
fd7b231f	94
a5403183 AK	95	if (bundle_encoding[template][slot] == B) {
	96	switch (major_opcode) {
	97	case INDIRECT_CALL_OPCODE:
	98	p->ainsn.inst_flag \|= INST_FLAG_FIX_BRANCH_REG;
	99	p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
	100	break;
	101	case IP_RELATIVE_PREDICT_OPCODE:
	102	case IP_RELATIVE_BRANCH_OPCODE:
	103	p->ainsn.inst_flag \|= INST_FLAG_FIX_RELATIVE_IP_ADDR;
	104	break;
	105	case IP_RELATIVE_CALL_OPCODE:
	106	p->ainsn.inst_flag \|= INST_FLAG_FIX_RELATIVE_IP_ADDR;
	107	p->ainsn.inst_flag \|= INST_FLAG_FIX_BRANCH_REG;
	108	p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
	109	break;
	110	}
	111	} else if (bundle_encoding[template][slot] == X) {
	112	switch (major_opcode) {
	113	case LONG_CALL_OPCODE:
	114	p->ainsn.inst_flag \|= INST_FLAG_FIX_BRANCH_REG;
	115	p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
	116	break;
	117	}
	118	}
	119	return;
	120	}
fd7b231f	121
708de8f1 AK	122	/*
	123	* In this function we check to see if the instruction
	124	* on which we are inserting kprobe is supported.
	125	* Returns 0 if supported
	126	* Returns -EINVAL if unsupported
	127	*/
	128	static int unsupported_inst(uint template, uint slot, uint major_opcode,
	129	unsigned long kprobe_inst, struct kprobe *p)
	130	{
	131	unsigned long addr = (unsigned long)p->addr;
	132
	133	if (bundle_encoding[template][slot] == I) {
	134	switch (major_opcode) {
	135	case 0x0: //I_UNIT_MISC_OPCODE:
	136	/*
	137	* Check for Integer speculation instruction
	138	* - Bit 33-35 to be equal to 0x1
	139	*/
	140	if (((kprobe_inst >> 33) & 0x7) == 1) {
	141	printk(KERN_WARNING
	142	"Kprobes on speculation inst at <0x%lx> not supported\n",
	143	addr);
	144	return -EINVAL;
	145	}
	146
	147	/*
	148	* IP relative mov instruction
	149	* - Bit 27-35 to be equal to 0x30
	150	*/
	151	if (((kprobe_inst >> 27) & 0x1FF) == 0x30) {
	152	printk(KERN_WARNING
	153	"Kprobes on \"mov r1=ip\" at <0x%lx> not supported\n",
	154	addr);
	155	return -EINVAL;
	156
	157	}
	158	}
	159	}
	160	return 0;
	161	}
	162
	163
1674eafc AK	164	/*
	165	* In this function we check to see if the instruction
	166	* (qp) cmpx.crel.ctype p1,p2=r2,r3
	167	* on which we are inserting kprobe is cmp instruction
	168	* with ctype as unc.
	169	*/
	170	static uint is_cmp_ctype_unc_inst(uint template, uint slot, uint major_opcode,
	171	unsigned long kprobe_inst)
	172	{
	173	cmp_inst_t cmp_inst;
	174	uint ctype_unc = 0;
	175
	176	if (!((bundle_encoding[template][slot] == I) \|\|
	177	(bundle_encoding[template][slot] == M)))
	178	goto out;
	179
	180	if (!((major_opcode == 0xC) \|\| (major_opcode == 0xD) \|\|
	181	(major_opcode == 0xE)))
	182	goto out;
	183
	184	cmp_inst.l = kprobe_inst;
	185	if ((cmp_inst.f.x2 == 0) \|\| (cmp_inst.f.x2 == 1)) {
	186	/* Integere compare - Register Register (A6 type)*/
	187	if ((cmp_inst.f.tb == 0) && (cmp_inst.f.ta == 0)
	188	&&(cmp_inst.f.c == 1))
	189	ctype_unc = 1;
	190	} else if ((cmp_inst.f.x2 == 2)\|\|(cmp_inst.f.x2 == 3)) {
	191	/* Integere compare - Immediate Register (A8 type)*/
	192	if ((cmp_inst.f.ta == 0) &&(cmp_inst.f.c == 1))
	193	ctype_unc = 1;
	194	}
	195	out:
	196	return ctype_unc;
	197	}
	198
a5403183 AK	199	/*
	200	* In this function we override the bundle with
	201	* the break instruction at the given slot.
	202	*/
	203	static void prepare_break_inst(uint template, uint slot, uint major_opcode,
	204	unsigned long kprobe_inst, struct kprobe *p)
	205	{
	206	unsigned long break_inst = BREAK_INST;
	207	bundle_t *bundle = &p->ainsn.insn.bundle;
	208
	209	/*
	210	* Copy the original kprobe_inst qualifying predicate(qp)
1674eafc AK	211	* to the break instruction iff !is_cmp_ctype_unc_inst
	212	* because for cmp instruction with ctype equal to unc,
	213	* which is a special instruction always needs to be
	214	* executed regradless of qp
a5403183	215	*/
1674eafc AK	216	if (!is_cmp_ctype_unc_inst(template, slot, major_opcode, kprobe_inst))
1674eafc AK	217	break_inst \|= (0x3f & kprobe_inst);
a5403183 AK	218
	219	switch (slot) {
	220	case 0:
	221	bundle->quad0.slot0 = break_inst;
	222	break;
	223	case 1:
	224	bundle->quad0.slot1_p0 = break_inst;
	225	bundle->quad1.slot1_p1 = break_inst >> (64-46);
	226	break;
	227	case 2:
	228	bundle->quad1.slot2 = break_inst;
	229	break;
8bc76772	230	}
cd2675bf	231
a5403183 AK	232	/*
	233	* Update the instruction flag, so that we can
	234	* emulate the instruction properly after we
	235	* single step on original instruction
	236	*/
	237	update_kprobe_inst_flag(template, slot, major_opcode, kprobe_inst, p);
	238	}
	239
	240	static inline void get_kprobe_inst(bundle_t *bundle, uint slot,
	241	unsigned long kprobe_inst, uint major_opcode)
	242	{
	243	unsigned long kprobe_inst_p0, kprobe_inst_p1;
	244	unsigned int template;
	245
	246	template = bundle->quad0.template;
fd7b231f	247
fd7b231f	248	switch (slot) {
a5403183 AK	249	case 0:
	250	*major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT);
	251	*kprobe_inst = bundle->quad0.slot0;
fd7b231f	252	break;
a5403183 AK	253	case 1:
	254	*major_opcode = (bundle->quad1.slot1_p1 >> SLOT1_p1_OPCODE_SHIFT);
	255	kprobe_inst_p0 = bundle->quad0.slot1_p0;
	256	kprobe_inst_p1 = bundle->quad1.slot1_p1;
	257	*kprobe_inst = kprobe_inst_p0 \| (kprobe_inst_p1 << (64-46));
fd7b231f	258	break;
a5403183 AK	259	case 2:
	260	*major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT);
	261	*kprobe_inst = bundle->quad1.slot2;
fd7b231f AK	262	break;
fd7b231f AK	263	}
a5403183	264	}
fd7b231f	265
a5403183 AK	266	static int valid_kprobe_addr(int template, int slot, unsigned long addr)
	267	{
	268	if ((slot > 2) \|\| ((bundle_encoding[template][1] == L) && slot > 1)) {
	269	printk(KERN_WARNING "Attempting to insert unaligned kprobe at 0x%lx\n",
	270	addr);
	271	return -EINVAL;
8bc76772	272	}
a5403183 AK	273	return 0;
	274	}
	275
852caccc AK	276	static inline void save_previous_kprobe(void)
	277	{
	278	kprobe_prev = current_kprobe;
	279	kprobe_status_prev = kprobe_status;
	280	}
	281
	282	static inline void restore_previous_kprobe(void)
	283	{
	284	current_kprobe = kprobe_prev;
	285	kprobe_status = kprobe_status_prev;
	286	}
	287
	288	static inline void set_current_kprobe(struct kprobe *p)
	289	{
	290	current_kprobe = p;
	291	}
	292
a5403183 AK	293	int arch_prepare_kprobe(struct kprobe *p)
	294	{
	295	unsigned long addr = (unsigned long) p->addr;
	296	unsigned long kprobe_addr = (unsigned long )(addr & ~0xFULL);
	297	unsigned long kprobe_inst=0;
	298	unsigned int slot = addr & 0xf, template, major_opcode = 0;
	299	bundle_t *bundle = &p->ainsn.insn.bundle;
	300
	301	memcpy(&p->opcode.bundle, kprobe_addr, sizeof(bundle_t));
	302	memcpy(&p->ainsn.insn.bundle, kprobe_addr, sizeof(bundle_t));
	303
	304	template = bundle->quad0.template;
	305
	306	if(valid_kprobe_addr(template, slot, addr))
	307	return -EINVAL;
	308
	309	/* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
	310	if (slot == 1 && bundle_encoding[template][1] == L)
	311	slot++;
	312
	313	/* Get kprobe_inst and major_opcode from the bundle */
	314	get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
	315
708de8f1 AK	316	if (unsupported_inst(template, slot, major_opcode, kprobe_inst, p))
	317	return -EINVAL;
	318
a5403183	319	prepare_break_inst(template, slot, major_opcode, kprobe_inst, p);
8bc76772 RL	320
	321	return 0;
	322	}
	323
	324	void arch_arm_kprobe(struct kprobe *p)
	325	{
	326	unsigned long addr = (unsigned long)p->addr;
	327	unsigned long arm_addr = addr & ~0xFULL;
	328
	329	memcpy((char *)arm_addr, &p->ainsn.insn.bundle, sizeof(bundle_t));
fd7b231f AK	330	flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t));
	331	}
	332
	333	void arch_disarm_kprobe(struct kprobe *p)
	334	{
	335	unsigned long addr = (unsigned long)p->addr;
	336	unsigned long arm_addr = addr & ~0xFULL;
	337
	338	/* p->opcode contains the original unaltered bundle */
	339	memcpy((char ) arm_addr, (char ) &p->opcode.bundle, sizeof(bundle_t));
	340	flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t));
	341	}
	342
	343	void arch_remove_kprobe(struct kprobe *p)
	344	{
	345	}
	346
	347	/*
	348	* We are resuming execution after a single step fault, so the pt_regs
	349	* structure reflects the register state after we executed the instruction
	350	* located in the kprobe (p->ainsn.insn.bundle). We still need to adjust
cd2675bf AK	351	* the ip to point back to the original stack address. To set the IP address
	352	* to original stack address, handle the case where we need to fixup the
	353	* relative IP address and/or fixup branch register.
fd7b231f AK	354	*/
	355	static void resume_execution(struct kprobe p, struct pt_regs regs)
	356	{
8bc76772	357	unsigned long bundle_addr = ((unsigned long) (&p->opcode.bundle)) & ~0xFULL;
cd2675bf AK	358	unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL;
	359	unsigned long template;
	360	int slot = ((unsigned long)p->addr & 0xf);
fd7b231f	361
cd2675bf AK	362	template = p->opcode.bundle.quad0.template;
	363
	364	if (slot == 1 && bundle_encoding[template][1] == L)
	365	slot = 2;
	366
	367	if (p->ainsn.inst_flag) {
	368
	369	if (p->ainsn.inst_flag & INST_FLAG_FIX_RELATIVE_IP_ADDR) {
	370	/* Fix relative IP address */
	371	regs->cr_iip = (regs->cr_iip - bundle_addr) + resume_addr;
	372	}
	373
	374	if (p->ainsn.inst_flag & INST_FLAG_FIX_BRANCH_REG) {
	375	/*
	376	* Fix target branch register, software convention is
	377	* to use either b0 or b6 or b7, so just checking
	378	* only those registers
	379	*/
	380	switch (p->ainsn.target_br_reg) {
	381	case 0:
	382	if ((regs->b0 == bundle_addr) \|\|
	383	(regs->b0 == bundle_addr + 0x10)) {
	384	regs->b0 = (regs->b0 - bundle_addr) +
	385	resume_addr;
	386	}
	387	break;
	388	case 6:
	389	if ((regs->b6 == bundle_addr) \|\|
	390	(regs->b6 == bundle_addr + 0x10)) {
	391	regs->b6 = (regs->b6 - bundle_addr) +
	392	resume_addr;
	393	}
	394	break;
	395	case 7:
	396	if ((regs->b7 == bundle_addr) \|\|
	397	(regs->b7 == bundle_addr + 0x10)) {
	398	regs->b7 = (regs->b7 - bundle_addr) +
	399	resume_addr;
	400	}
	401	break;
	402	} /* end switch */
	403	}
	404	goto turn_ss_off;
	405	}
fd7b231f	406
cd2675bf AK	407	if (slot == 2) {
	408	if (regs->cr_iip == bundle_addr + 0x10) {
	409	regs->cr_iip = resume_addr + 0x10;
	410	}
	411	} else {
	412	if (regs->cr_iip == bundle_addr) {
	413	regs->cr_iip = resume_addr;
	414	}
a5403183	415	}
fd7b231f	416
cd2675bf AK	417	turn_ss_off:
	418	/* Turn off Single Step bit */
	419	ia64_psr(regs)->ss = 0;
fd7b231f AK	420	}
	421
	422	static void prepare_ss(struct kprobe p, struct pt_regs regs)
	423	{
8bc76772	424	unsigned long bundle_addr = (unsigned long) &p->opcode.bundle;
fd7b231f AK	425	unsigned long slot = (unsigned long)p->addr & 0xf;
	426
	427	/* Update instruction pointer (IIP) and slot number (IPSR.ri) */
	428	regs->cr_iip = bundle_addr & ~0xFULL;
	429
	430	if (slot > 2)
	431	slot = 0;
	432
	433	ia64_psr(regs)->ri = slot;
	434
	435	/* turn on single stepping */
	436	ia64_psr(regs)->ss = 1;
	437	}
	438
89cb14c0	439	static int pre_kprobes_handler(struct die_args *args)
fd7b231f AK	440	{
	441	struct kprobe *p;
	442	int ret = 0;
89cb14c0	443	struct pt_regs *regs = args->regs;
fd7b231f AK	444	kprobe_opcode_t addr = (kprobe_opcode_t )instruction_pointer(regs);
	445
	446	preempt_disable();
	447
	448	/* Handle recursion cases */
	449	if (kprobe_running()) {
	450	p = get_kprobe(addr);
	451	if (p) {
	452	if (kprobe_status == KPROBE_HIT_SS) {
	453	unlock_kprobes();
	454	goto no_kprobe;
	455	}
852caccc AK	456	/* We have reentered the pre_kprobe_handler(), since
	457	* another probe was hit while within the handler.
	458	* We here save the original kprobes variables and
	459	* just single step on the instruction of the new probe
	460	* without calling any user handlers.
	461	*/
	462	save_previous_kprobe();
	463	set_current_kprobe(p);
	464	p->nmissed++;
	465	prepare_ss(p, regs);
	466	kprobe_status = KPROBE_REENTER;
	467	return 1;
89cb14c0	468	} else if (args->err == __IA64_BREAK_JPROBE) {
fd7b231f AK	469	/*
	470	* jprobe instrumented function just completed
	471	*/
	472	p = current_kprobe;
	473	if (p->break_handler && p->break_handler(p, regs)) {
	474	goto ss_probe;
	475	}
89cb14c0 KA	476	} else {
	477	/* Not our break */
	478	goto no_kprobe;
fd7b231f AK	479	}
	480	}
	481
	482	lock_kprobes();
	483	p = get_kprobe(addr);
	484	if (!p) {
	485	unlock_kprobes();
	486	goto no_kprobe;
	487	}
	488
	489	kprobe_status = KPROBE_HIT_ACTIVE;
852caccc	490	set_current_kprobe(p);
fd7b231f AK	491
	492	if (p->pre_handler && p->pre_handler(p, regs))
	493	/*
	494	* Our pre-handler is specifically requesting that we just
	495	* do a return. This is handling the case where the
	496	* pre-handler is really our special jprobe pre-handler.
	497	*/
	498	return 1;
	499
	500	ss_probe:
	501	prepare_ss(p, regs);
	502	kprobe_status = KPROBE_HIT_SS;
	503	return 1;
	504
	505	no_kprobe:
	506	preempt_enable_no_resched();
	507	return ret;
	508	}
	509
	510	static int post_kprobes_handler(struct pt_regs *regs)
	511	{
	512	if (!kprobe_running())
	513	return 0;
	514
852caccc AK	515	if ((kprobe_status != KPROBE_REENTER) && current_kprobe->post_handler) {
852caccc AK	516	kprobe_status = KPROBE_HIT_SSDONE;
fd7b231f	517	current_kprobe->post_handler(current_kprobe, regs, 0);
852caccc	518	}
fd7b231f AK	519
	520	resume_execution(current_kprobe, regs);
	521
852caccc AK	522	/Restore back the original saved kprobes variables and continue. /
	523	if (kprobe_status == KPROBE_REENTER) {
	524	restore_previous_kprobe();
	525	goto out;
	526	}
	527
fd7b231f	528	unlock_kprobes();
852caccc AK	529
852caccc AK	530	out:
fd7b231f AK	531	preempt_enable_no_resched();
	532	return 1;
	533	}
	534
	535	static int kprobes_fault_handler(struct pt_regs *regs, int trapnr)
	536	{
	537	if (!kprobe_running())
	538	return 0;
	539
	540	if (current_kprobe->fault_handler &&
	541	current_kprobe->fault_handler(current_kprobe, regs, trapnr))
	542	return 1;
	543
	544	if (kprobe_status & KPROBE_HIT_SS) {
	545	resume_execution(current_kprobe, regs);
	546	unlock_kprobes();
	547	preempt_enable_no_resched();
	548	}
	549
	550	return 0;
	551	}
	552
	553	int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val,
	554	void *data)
	555	{
	556	struct die_args args = (struct die_args )data;
	557	switch(val) {
	558	case DIE_BREAK:
89cb14c0	559	if (pre_kprobes_handler(args))
fd7b231f AK	560	return NOTIFY_STOP;
	561	break;
	562	case DIE_SS:
	563	if (post_kprobes_handler(args->regs))
	564	return NOTIFY_STOP;
	565	break;
	566	case DIE_PAGE_FAULT:
	567	if (kprobes_fault_handler(args->regs, args->trapnr))
	568	return NOTIFY_STOP;
	569	default:
	570	break;
	571	}
	572	return NOTIFY_DONE;
	573	}
	574
	575	int setjmp_pre_handler(struct kprobe p, struct pt_regs regs)
	576	{
b2761dc2 AK	577	struct jprobe *jp = container_of(p, struct jprobe, kp);
b2761dc2 AK	578	unsigned long addr = ((struct fnptr *)(jp->entry))->ip;
fd7b231f	579
b2761dc2 AK	580	/* save architectural state */
	581	jprobe_saved_regs = *regs;
	582
	583	/* after rfi, execute the jprobe instrumented function */
	584	regs->cr_iip = addr & ~0xFULL;
	585	ia64_psr(regs)->ri = addr & 0xf;
	586	regs->r1 = ((struct fnptr *)(jp->entry))->gp;
	587
	588	/*
	589	* fix the return address to our jprobe_inst_return() function
	590	* in the jprobes.S file
	591	*/
	592	regs->b0 = ((struct fnptr *)(jprobe_inst_return))->ip;
	593
	594	return 1;
fd7b231f AK	595	}
	596
	597	int longjmp_break_handler(struct kprobe p, struct pt_regs regs)
	598	{
b2761dc2 AK	599	*regs = jprobe_saved_regs;
b2761dc2 AK	600	return 1;
fd7b231f	601	}