Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 933 insertions, 0 deletions

diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
new file mode 100644
index 000000000..ca4b4fa45
--- /dev/null
+++ b/arch/ia64/kernel/kprobes.c
@@ -0,0 +1,933 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Kernel Probes (KProbes)
+ *  arch/ia64/kernel/kprobes.c
+ *
+ * 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/kprobes.h>
+#include <linux/ptrace.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/preempt.h>
+#include <linux/extable.h>
+#include <linux/kdebug.h>
+#include <linux/pgtable.h>
+
+#include <asm/sections.h>
+#include <asm/exception.h>
+
+DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
+DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
+
+struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
+
+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 */
+};
+
+/* Insert a long branch code */
+static void __kprobes set_brl_inst(void *from, void *to)
+{
+	s64 rel = ((s64) to - (s64) from) >> 4;
+	bundle_t *brl;
+	brl = (bundle_t *) ((u64) from & ~0xf);
+	brl->quad0.template = 0x05;	/* [MLX](stop) */
+	brl->quad0.slot0 = NOP_M_INST;	/* nop.m 0x0 */
+	brl->quad0.slot1_p0 = ((rel >> 20) & 0x7fffffffff) << 2;
+	brl->quad1.slot1_p1 = (((rel >> 20) & 0x7fffffffff) << 2) >> (64 - 46);
+	/* brl.cond.sptk.many.clr rel<<4 (qp=0) */
+	brl->quad1.slot2 = BRL_INST(rel >> 59, rel & 0xfffff);
+}
+
+/*
+ * In this function we check to see if the instruction
+ * is IP relative instruction and update the kprobe
+ * inst flag accordingly
+ */
+static void __kprobes 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;
+	p->ainsn.slot = slot;
+
+	/* Check for Break instruction
+	 * Bits 37:40 Major opcode to be zero
+	 * Bits 27:32 X6 to be zero
+	 * Bits 32:35 X3 to be zero
+	 */
+	if ((!major_opcode) && (!((kprobe_inst >> 27) & 0x1FF)) ) {
+		/* is a break instruction */
+	 	p->ainsn.inst_flag |= INST_FLAG_BREAK_INST;
+		return;
+	}
+
+	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
+ * (qp) cmpx.crel.ctype p1,p2=r2,r3
+ * on which we are inserting kprobe is cmp instruction
+ * with ctype as unc.
+ */
+static uint __kprobes 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)) {
+		/* Integer 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)) {
+		/* Integer 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 check to see if the instruction
+ * on which we are inserting kprobe is supported.
+ * Returns qp value if supported
+ * Returns -EINVAL if unsupported
+ */
+static int __kprobes unsupported_inst(uint template, uint  slot,
+				      uint major_opcode,
+				      unsigned long kprobe_inst,
+				      unsigned long addr)
+{
+	int qp;
+
+	qp = kprobe_inst & 0x3f;
+	if (is_cmp_ctype_unc_inst(template, slot, major_opcode, kprobe_inst)) {
+		if (slot == 1 && qp)  {
+			printk(KERN_WARNING "Kprobes on cmp unc "
+					"instruction on slot 1 at <0x%lx> "
+					"is not supported\n", addr);
+			return -EINVAL;
+
+		}
+		qp = 0;
+	}
+	else if (bundle_encoding[template][slot] == I) {
+		if (major_opcode == 0) {
+			/*
+			 * 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;
+
+			}
+		}
+		else if ((major_opcode == 5) &&	!(kprobe_inst & (0xFUl << 33)) &&
+				(kprobe_inst & (0x1UL << 12))) {
+			/* test bit instructions, tbit,tnat,tf
+			 * bit 33-36 to be equal to 0
+			 * bit 12 to be equal to 1
+			 */
+			if (slot == 1 && qp) {
+				printk(KERN_WARNING "Kprobes on test bit "
+						"instruction on slot at <0x%lx> "
+						"is not supported\n", addr);
+				return -EINVAL;
+			}
+			qp = 0;
+		}
+	}
+	else if (bundle_encoding[template][slot] == B) {
+		if (major_opcode == 7) {
+			/* IP-Relative Predict major code is 7 */
+			printk(KERN_WARNING "Kprobes on IP-Relative"
+					"Predict is not supported\n");
+			return -EINVAL;
+		}
+		else if (major_opcode == 2) {
+			/* Indirect Predict, major code is 2
+			 * bit 27-32 to be equal to 10 or 11
+			 */
+			int x6=(kprobe_inst >> 27) & 0x3F;
+			if ((x6 == 0x10) || (x6 == 0x11)) {
+				printk(KERN_WARNING "Kprobes on "
+					"Indirect Predict is not supported\n");
+				return -EINVAL;
+			}
+		}
+	}
+	/* kernel does not use float instruction, here for safety kprobe
+	 * will judge whether it is fcmp/flass/float approximation instruction
+	 */
+	else if (unlikely(bundle_encoding[template][slot] == F)) {
+		if ((major_opcode == 4 || major_opcode == 5) &&
+				(kprobe_inst  & (0x1 << 12))) {
+			/* fcmp/fclass unc instruction */
+			if (slot == 1 && qp) {
+				printk(KERN_WARNING "Kprobes on fcmp/fclass "
+					"instruction on slot at <0x%lx> "
+					"is not supported\n", addr);
+				return -EINVAL;
+
+			}
+			qp = 0;
+		}
+		if ((major_opcode == 0 || major_opcode == 1) &&
+			(kprobe_inst & (0x1UL << 33))) {
+			/* float Approximation instruction */
+			if (slot == 1 && qp) {
+				printk(KERN_WARNING "Kprobes on float Approx "
+					"instr at <0x%lx> is not supported\n",
+						addr);
+				return -EINVAL;
+			}
+			qp = 0;
+		}
+	}
+	return qp;
+}
+
+/*
+ * In this function we override the bundle with
+ * the break instruction at the given slot.
+ */
+static void __kprobes prepare_break_inst(uint template, uint  slot,
+					 uint major_opcode,
+					 unsigned long kprobe_inst,
+					 struct kprobe *p,
+					 int qp)
+{
+	unsigned long break_inst = BREAK_INST;
+	bundle_t *bundle = &p->opcode.bundle;
+
+	/*
+	 * Copy the original kprobe_inst qualifying predicate(qp)
+	 * to the break instruction
+	 */
+	break_inst |= qp;
+
+	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 void __kprobes 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;
+	}
+}
+
+/* Returns non-zero if the addr is in the Interrupt Vector Table */
+static int __kprobes in_ivt_functions(unsigned long addr)
+{
+	return (addr >= (unsigned long)__start_ivt_text
+		&& addr < (unsigned long)__end_ivt_text);
+}
+
+static int __kprobes 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;
+	}
+
+	if (in_ivt_functions(addr)) {
+		printk(KERN_WARNING "Kprobes can't be inserted inside "
+				"IVT functions at 0x%lx\n", addr);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+	unsigned int i;
+	i = atomic_add_return(1, &kcb->prev_kprobe_index);
+	kcb->prev_kprobe[i-1].kp = kprobe_running();
+	kcb->prev_kprobe[i-1].status = kcb->kprobe_status;
+}
+
+static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+	unsigned int i;
+	i = atomic_read(&kcb->prev_kprobe_index);
+	__this_cpu_write(current_kprobe, kcb->prev_kprobe[i-1].kp);
+	kcb->kprobe_status = kcb->prev_kprobe[i-1].status;
+	atomic_sub(1, &kcb->prev_kprobe_index);
+}
+
+static void __kprobes set_current_kprobe(struct kprobe *p,
+			struct kprobe_ctlblk *kcb)
+{
+	__this_cpu_write(current_kprobe, p);
+}
+
+static void kretprobe_trampoline(void)
+{
+}
+
+int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
+{
+	regs->cr_iip = __kretprobe_trampoline_handler(regs,
+		dereference_function_descriptor(kretprobe_trampoline), NULL);
+	/*
+	 * 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;
+}
+
+void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
+				      struct pt_regs *regs)
+{
+	ri->ret_addr = (kprobe_opcode_t *)regs->b0;
+	ri->fp = NULL;
+
+	/* Replace the return addr with trampoline addr */
+	regs->b0 = (unsigned long)dereference_function_descriptor(kretprobe_trampoline);
+}
+
+/* Check the instruction in the slot is break */
+static int __kprobes __is_ia64_break_inst(bundle_t *bundle, uint slot)
+{
+	unsigned int major_opcode;
+	unsigned int template = bundle->quad0.template;
+	unsigned long kprobe_inst;
+
+	/* 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 probe instruction at given slot*/
+	get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
+
+	/* For break instruction,
+	 * Bits 37:40 Major opcode to be zero
+	 * Bits 27:32 X6 to be zero
+	 * Bits 32:35 X3 to be zero
+	 */
+	if (major_opcode || ((kprobe_inst >> 27) & 0x1FF)) {
+		/* Not a break instruction */
+		return 0;
+	}
+
+	/* Is a break instruction */
+	return 1;
+}
+
+/*
+ * In this function, we check whether the target bundle modifies IP or
+ * it triggers an exception. If so, it cannot be boostable.
+ */
+static int __kprobes can_boost(bundle_t *bundle, uint slot,
+			       unsigned long bundle_addr)
+{
+	unsigned int template = bundle->quad0.template;
+
+	do {
+		if (search_exception_tables(bundle_addr + slot) ||
+		    __is_ia64_break_inst(bundle, slot))
+			return 0;	/* exception may occur in this bundle*/
+	} while ((++slot) < 3);
+	template &= 0x1e;
+	if (template >= 0x10 /* including B unit */ ||
+	    template == 0x04 /* including X unit */ ||
+	    template == 0x06) /* undefined */
+		return 0;
+
+	return 1;
+}
+
+/* Prepare long jump bundle and disables other boosters if need */
+static void __kprobes prepare_booster(struct kprobe *p)
+{
+	unsigned long addr = (unsigned long)p->addr & ~0xFULL;
+	unsigned int slot = (unsigned long)p->addr & 0xf;
+	struct kprobe *other_kp;
+
+	if (can_boost(&p->ainsn.insn[0].bundle, slot, addr)) {
+		set_brl_inst(&p->ainsn.insn[1].bundle, (bundle_t *)addr + 1);
+		p->ainsn.inst_flag |= INST_FLAG_BOOSTABLE;
+	}
+
+	/* disables boosters in previous slots */
+	for (; addr < (unsigned long)p->addr; addr++) {
+		other_kp = get_kprobe((void *)addr);
+		if (other_kp)
+			other_kp->ainsn.inst_flag &= ~INST_FLAG_BOOSTABLE;
+	}
+}
+
+int __kprobes 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;
+	int qp;
+
+	bundle = &((kprobe_opcode_t *)kprobe_addr)->bundle;
+	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);
+
+	qp = unsupported_inst(template, slot, major_opcode, kprobe_inst, addr);
+	if (qp < 0)
+		return -EINVAL;
+
+	p->ainsn.insn = get_insn_slot();
+	if (!p->ainsn.insn)
+		return -ENOMEM;
+	memcpy(&p->opcode, kprobe_addr, sizeof(kprobe_opcode_t));
+	memcpy(p->ainsn.insn, kprobe_addr, sizeof(kprobe_opcode_t));
+
+	prepare_break_inst(template, slot, major_opcode, kprobe_inst, p, qp);
+
+	prepare_booster(p);
+
+	return 0;
+}
+
+void __kprobes arch_arm_kprobe(struct kprobe *p)
+{
+	unsigned long arm_addr;
+	bundle_t *src, *dest;
+
+	arm_addr = ((unsigned long)p->addr) & ~0xFUL;
+	dest = &((kprobe_opcode_t *)arm_addr)->bundle;
+	src = &p->opcode.bundle;
+
+	flush_icache_range((unsigned long)p->ainsn.insn,
+			   (unsigned long)p->ainsn.insn +
+			   sizeof(kprobe_opcode_t) * MAX_INSN_SIZE);
+
+	switch (p->ainsn.slot) {
+		case 0:
+			dest->quad0.slot0 = src->quad0.slot0;
+			break;
+		case 1:
+			dest->quad1.slot1_p1 = src->quad1.slot1_p1;
+			break;
+		case 2:
+			dest->quad1.slot2 = src->quad1.slot2;
+			break;
+	}
+	flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
+}
+
+void __kprobes arch_disarm_kprobe(struct kprobe *p)
+{
+	unsigned long arm_addr;
+	bundle_t *src, *dest;
+
+	arm_addr = ((unsigned long)p->addr) & ~0xFUL;
+	dest = &((kprobe_opcode_t *)arm_addr)->bundle;
+	/* p->ainsn.insn contains the original unaltered kprobe_opcode_t */
+	src = &p->ainsn.insn->bundle;
+	switch (p->ainsn.slot) {
+		case 0:
+			dest->quad0.slot0 = src->quad0.slot0;
+			break;
+		case 1:
+			dest->quad1.slot1_p1 = src->quad1.slot1_p1;
+			break;
+		case 2:
+			dest->quad1.slot2 = src->quad1.slot2;
+			break;
+	}
+	flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
+}
+
+void __kprobes arch_remove_kprobe(struct kprobe *p)
+{
+	if (p->ainsn.insn) {
+		free_insn_slot(p->ainsn.insn,
+			       p->ainsn.inst_flag & INST_FLAG_BOOSTABLE);
+		p->ainsn.insn = NULL;
+	}
+}
+/*
+ * 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 __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
+{
+	unsigned long bundle_addr = (unsigned long) (&p->ainsn.insn->bundle);
+	unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL;
+	unsigned long template;
+	int slot = ((unsigned long)p->addr & 0xf);
+
+	template = p->ainsn.insn->bundle.quad0.template;
+
+	if (slot == 1 && bundle_encoding[template][1] == L)
+		slot = 2;
+
+	if (p->ainsn.inst_flag & ~INST_FLAG_BOOSTABLE) {
+
+		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 __kprobes prepare_ss(struct kprobe *p, struct pt_regs *regs)
+{
+	unsigned long bundle_addr = (unsigned long) &p->ainsn.insn->bundle;
+	unsigned long slot = (unsigned long)p->addr & 0xf;
+
+	/* single step inline if break instruction */
+	if (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)
+		regs->cr_iip = (unsigned long)p->addr & ~0xFULL;
+	else
+		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 __kprobes is_ia64_break_inst(struct pt_regs *regs)
+{
+	unsigned int slot = ia64_psr(regs)->ri;
+	unsigned long *kprobe_addr = (unsigned long *)regs->cr_iip;
+	bundle_t bundle;
+
+	memcpy(&bundle, kprobe_addr, sizeof(bundle_t));
+
+	return __is_ia64_break_inst(&bundle, slot);
+}
+
+static int __kprobes 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);
+	struct kprobe_ctlblk *kcb;
+
+	/*
+	 * We don't want to be preempted for the entire
+	 * duration of kprobe processing
+	 */
+	preempt_disable();
+	kcb = get_kprobe_ctlblk();
+
+	/* Handle recursion cases */
+	if (kprobe_running()) {
+		p = get_kprobe(addr);
+		if (p) {
+			if ((kcb->kprobe_status == KPROBE_HIT_SS) &&
+	 		     (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)) {
+				ia64_psr(regs)->ss = 0;
+				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(kcb);
+			set_current_kprobe(p, kcb);
+			kprobes_inc_nmissed_count(p);
+			prepare_ss(p, regs);
+			kcb->kprobe_status = KPROBE_REENTER;
+			return 1;
+		} else if (!is_ia64_break_inst(regs)) {
+			/* The breakpoint instruction was removed by
+			 * another cpu right after we hit, no further
+			 * handling of this interrupt is appropriate
+			 */
+			ret = 1;
+			goto no_kprobe;
+		} else {
+			/* Not our break */
+			goto no_kprobe;
+		}
+	}
+
+	p = get_kprobe(addr);
+	if (!p) {
+		if (!is_ia64_break_inst(regs)) {
+			/*
+			 * 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 our break, let kernel handle it */
+		goto no_kprobe;
+	}
+
+	set_current_kprobe(p, kcb);
+	kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+
+	if (p->pre_handler && p->pre_handler(p, regs)) {
+		reset_current_kprobe();
+		preempt_enable_no_resched();
+		return 1;
+	}
+
+#if !defined(CONFIG_PREEMPTION)
+	if (p->ainsn.inst_flag == INST_FLAG_BOOSTABLE && !p->post_handler) {
+		/* Boost up -- we can execute copied instructions directly */
+		ia64_psr(regs)->ri = p->ainsn.slot;
+		regs->cr_iip = (unsigned long)&p->ainsn.insn->bundle & ~0xFULL;
+		/* turn single stepping off */
+		ia64_psr(regs)->ss = 0;
+
+		reset_current_kprobe();
+		preempt_enable_no_resched();
+		return 1;
+	}
+#endif
+	prepare_ss(p, regs);
+	kcb->kprobe_status = KPROBE_HIT_SS;
+	return 1;
+
+no_kprobe:
+	preempt_enable_no_resched();
+	return ret;
+}
+
+static int __kprobes post_kprobes_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();
+	return 1;
+}
+
+int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+{
+	struct kprobe *cur = kprobe_running();
+	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+
+	switch(kcb->kprobe_status) {
+	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 instruction pointer points back to
+		 * the probe address and allow the page fault handler
+		 * to continue as a normal page fault.
+		 */
+		regs->cr_iip = ((unsigned long)cur->addr) & ~0xFULL;
+		ia64_psr(regs)->ri = ((unsigned long)cur->addr) & 0xf;
+		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 accounting
+		 * 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.
+		 */
+		if (ia64_done_with_exception(regs))
+			return 1;
+
+		/*
+		 * Let ia64_do_page_fault() fix it.
+		 */
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+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;
+
+	if (args->regs && user_mode(args->regs))
+		return ret;
+
+	switch(val) {
+	case DIE_BREAK:
+		/* err is break number from ia64_bad_break() */
+		if ((args->err >> 12) == (__IA64_BREAK_KPROBE >> 12)
+			|| args->err == 0)
+			if (pre_kprobes_handler(args))
+				ret = NOTIFY_STOP;
+		break;
+	case DIE_FAULT:
+		/* err is vector number from ia64_fault() */
+		if (args->err == 36)
+			if (post_kprobes_handler(args->regs))
+				ret = NOTIFY_STOP;
+		break;
+	default:
+		break;
+	}
+	return ret;
+}
+
+unsigned long arch_deref_entry_point(void *entry)
+{
+	return ((struct fnptr *)entry)->ip;
+}
+
+static struct kprobe trampoline_p = {
+	.pre_handler = trampoline_probe_handler
+};
+
+int __init arch_init_kprobes(void)
+{
+	trampoline_p.addr =
+		dereference_function_descriptor(kretprobe_trampoline);
+	return register_kprobe(&trampoline_p);
+}
+
+int __kprobes arch_trampoline_kprobe(struct kprobe *p)
+{
+	if (p->addr ==
+		dereference_function_descriptor(kretprobe_trampoline))
+		return 1;
+
+	return 0;
+}