1 files changed, 255 insertions, 317 deletions

diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 2156ea90eb54..c0d9f12cb441 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -1,20 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *  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, 2004
  *
  * 2002-Oct	Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
@@ -29,28 +16,140 @@
 #include <linux/kprobes.h>
 #include <linux/ptrace.h>
 #include <linux/preempt.h>
-#include <linux/module.h>
+#include <linux/extable.h>
 #include <linux/kdebug.h>
 #include <linux/slab.h>
+#include <linux/set_memory.h>
+#include <linux/execmem.h>
+#include <asm/text-patching.h>
 #include <asm/cacheflush.h>
 #include <asm/sstep.h>
-#include <asm/uaccess.h>
+#include <asm/sections.h>
+#include <asm/inst.h>
+#include <linux/uaccess.h>
 
 DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
 DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 
 struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
 
-int __kprobes arch_prepare_kprobe(struct kprobe *p)
+bool arch_within_kprobe_blacklist(unsigned long addr)
+{
+	return  (addr >= (unsigned long)__kprobes_text_start &&
+		 addr < (unsigned long)__kprobes_text_end) ||
+		(addr >= (unsigned long)_stext &&
+		 addr < (unsigned long)__head_end);
+}
+
+kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset)
+{
+	kprobe_opcode_t *addr = NULL;
+
+#ifdef CONFIG_PPC64_ELF_ABI_V2
+	/* PPC64 ABIv2 needs local entry point */
+	addr = (kprobe_opcode_t *)kallsyms_lookup_name(name);
+	if (addr && !offset) {
+#ifdef CONFIG_KPROBES_ON_FTRACE
+		unsigned long faddr;
+		/*
+		 * Per livepatch.h, ftrace location is always within the first
+		 * 16 bytes of a function on powerpc with -mprofile-kernel.
+		 */
+		faddr = ftrace_location_range((unsigned long)addr,
+					      (unsigned long)addr + 16);
+		if (faddr)
+			addr = (kprobe_opcode_t *)faddr;
+		else
+#endif
+			addr = (kprobe_opcode_t *)ppc_function_entry(addr);
+	}
+#elif defined(CONFIG_PPC64_ELF_ABI_V1)
+	/*
+	 * 64bit powerpc ABIv1 uses function descriptors:
+	 * - Check for the dot variant of the symbol first.
+	 * - If that fails, try looking up the symbol provided.
+	 *
+	 * This ensures we always get to the actual symbol and not
+	 * the descriptor.
+	 *
+	 * Also handle <module:symbol> format.
+	 */
+	char dot_name[MODULE_NAME_LEN + 1 + KSYM_NAME_LEN];
+	bool dot_appended = false;
+	const char *c;
+	ssize_t ret = 0;
+	int len = 0;
+
+	if ((c = strnchr(name, MODULE_NAME_LEN, ':')) != NULL) {
+		c++;
+		len = c - name;
+		memcpy(dot_name, name, len);
+	} else
+		c = name;
+
+	if (*c != '\0' && *c != '.') {
+		dot_name[len++] = '.';
+		dot_appended = true;
+	}
+	ret = strscpy(dot_name + len, c, KSYM_NAME_LEN);
+	if (ret > 0)
+		addr = (kprobe_opcode_t *)kallsyms_lookup_name(dot_name);
+
+	/* Fallback to the original non-dot symbol lookup */
+	if (!addr && dot_appended)
+		addr = (kprobe_opcode_t *)kallsyms_lookup_name(name);
+#else
+	addr = (kprobe_opcode_t *)kallsyms_lookup_name(name);
+#endif
+
+	return addr;
+}
+
+static bool arch_kprobe_on_func_entry(unsigned long addr, unsigned long offset)
+{
+	unsigned long ip = ftrace_location(addr);
+
+	if (ip)
+		return offset <= (ip - addr);
+	if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2) && !IS_ENABLED(CONFIG_PPC_KERNEL_PCREL))
+		return offset <= 8;
+	return !offset;
+}
+
+/* XXX try and fold the magic of kprobe_lookup_name() in this */
+kprobe_opcode_t *arch_adjust_kprobe_addr(unsigned long addr, unsigned long offset,
+					 bool *on_func_entry)
+{
+	*on_func_entry = arch_kprobe_on_func_entry(addr, offset);
+	return (kprobe_opcode_t *)(addr + offset);
+}
+
+int arch_prepare_kprobe(struct kprobe *p)
 {
 	int ret = 0;
-	kprobe_opcode_t insn = *p->addr;
+	struct kprobe *prev;
+	ppc_inst_t insn = ppc_inst_read(p->addr);
 
 	if ((unsigned long)p->addr & 0x03) {
 		printk("Attempt to register kprobe at an unaligned address\n");
 		ret = -EINVAL;
-	} else if (IS_MTMSRD(insn) || IS_RFID(insn) || IS_RFI(insn)) {
-		printk("Cannot register a kprobe on rfi/rfid or mtmsr[d]\n");
+	} else if (!can_single_step(ppc_inst_val(insn))) {
+		printk("Cannot register a kprobe on instructions that can't be single stepped\n");
+		ret = -EINVAL;
+	} else if ((unsigned long)p->addr & ~PAGE_MASK &&
+		   ppc_inst_prefixed(ppc_inst_read(p->addr - 1))) {
+		printk("Cannot register a kprobe on the second word of prefixed instruction\n");
+		ret = -EINVAL;
+	}
+	prev = get_kprobe(p->addr - 1);
+
+	/*
+	 * When prev is a ftrace-based kprobe, we don't have an insn, and it
+	 * doesn't probe for prefixed instruction.
+	 */
+	if (prev && !kprobe_ftrace(prev) &&
+	    ppc_inst_prefixed(ppc_inst_read(prev->ainsn.insn))) {
+		printk("Cannot register a kprobe on the second word of prefixed instruction\n");
 		ret = -EINVAL;
 	}
 
@@ -63,40 +162,37 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
 	}
 
 	if (!ret) {
-		memcpy(p->ainsn.insn, p->addr,
-				MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
-		p->opcode = *p->addr;
-		flush_icache_range((unsigned long)p->ainsn.insn,
-			(unsigned long)p->ainsn.insn + sizeof(kprobe_opcode_t));
+		patch_instruction(p->ainsn.insn, insn);
+		p->opcode = ppc_inst_val(insn);
 	}
 
 	p->ainsn.boostable = 0;
 	return ret;
 }
+NOKPROBE_SYMBOL(arch_prepare_kprobe);
 
-void __kprobes arch_arm_kprobe(struct kprobe *p)
+void arch_arm_kprobe(struct kprobe *p)
 {
-	*p->addr = BREAKPOINT_INSTRUCTION;
-	flush_icache_range((unsigned long) p->addr,
-			   (unsigned long) p->addr + sizeof(kprobe_opcode_t));
+	WARN_ON_ONCE(patch_instruction(p->addr, ppc_inst(BREAKPOINT_INSTRUCTION)));
 }
+NOKPROBE_SYMBOL(arch_arm_kprobe);
 
-void __kprobes arch_disarm_kprobe(struct kprobe *p)
+void arch_disarm_kprobe(struct kprobe *p)
 {
-	*p->addr = p->opcode;
-	flush_icache_range((unsigned long) p->addr,
-			   (unsigned long) p->addr + sizeof(kprobe_opcode_t));
+	WARN_ON_ONCE(patch_instruction(p->addr, ppc_inst(p->opcode)));
 }
+NOKPROBE_SYMBOL(arch_disarm_kprobe);
 
-void __kprobes arch_remove_kprobe(struct kprobe *p)
+void arch_remove_kprobe(struct kprobe *p)
 {
 	if (p->ainsn.insn) {
 		free_insn_slot(p->ainsn.insn, 0);
 		p->ainsn.insn = NULL;
 	}
 }
+NOKPROBE_SYMBOL(arch_remove_kprobe);
 
-static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
+static nokprobe_inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
 {
 	enable_single_step(regs);
 
@@ -106,46 +202,85 @@ static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
 	 * variant as values in regs could play a part in
 	 * if the trap is taken or not
 	 */
-	regs->nip = (unsigned long)p->ainsn.insn;
+	regs_set_return_ip(regs, (unsigned long)p->ainsn.insn);
 }
 
-static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
+static nokprobe_inline void save_previous_kprobe(struct kprobe_ctlblk *kcb)
 {
 	kcb->prev_kprobe.kp = kprobe_running();
 	kcb->prev_kprobe.status = kcb->kprobe_status;
 	kcb->prev_kprobe.saved_msr = kcb->kprobe_saved_msr;
 }
 
-static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
+static nokprobe_inline void restore_previous_kprobe(struct kprobe_ctlblk *kcb)
 {
-	__get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
+	__this_cpu_write(current_kprobe, kcb->prev_kprobe.kp);
 	kcb->kprobe_status = kcb->prev_kprobe.status;
 	kcb->kprobe_saved_msr = kcb->prev_kprobe.saved_msr;
 }
 
-static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
+static nokprobe_inline void set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
 				struct kprobe_ctlblk *kcb)
 {
-	__get_cpu_var(current_kprobe) = p;
+	__this_cpu_write(current_kprobe, p);
 	kcb->kprobe_saved_msr = regs->msr;
 }
 
-void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
-				      struct pt_regs *regs)
+static int try_to_emulate(struct kprobe *p, struct pt_regs *regs)
 {
-	ri->ret_addr = (kprobe_opcode_t *)regs->link;
+	int ret;
+	ppc_inst_t insn = ppc_inst_read(p->ainsn.insn);
 
-	/* Replace the return addr with trampoline addr */
-	regs->link = (unsigned long)kretprobe_trampoline;
+	/* regs->nip is also adjusted if emulate_step returns 1 */
+	ret = emulate_step(regs, insn);
+	if (ret > 0) {
+		/*
+		 * Once this instruction has been boosted
+		 * successfully, set the boostable flag
+		 */
+		if (unlikely(p->ainsn.boostable == 0))
+			p->ainsn.boostable = 1;
+	} else if (ret < 0) {
+		/*
+		 * We don't allow kprobes on mtmsr(d)/rfi(d), etc.
+		 * So, we should never get here... but, its still
+		 * good to catch them, just in case...
+		 */
+		printk("Can't step on instruction %08lx\n", ppc_inst_as_ulong(insn));
+		BUG();
+	} else {
+		/*
+		 * If we haven't previously emulated this instruction, then it
+		 * can't be boosted. Note it down so we don't try to do so again.
+		 *
+		 * If, however, we had emulated this instruction in the past,
+		 * then this is just an error with the current run (for
+		 * instance, exceptions due to a load/store). We return 0 so
+		 * that this is now single-stepped, but continue to try
+		 * emulating it in subsequent probe hits.
+		 */
+		if (unlikely(p->ainsn.boostable != 1))
+			p->ainsn.boostable = -1;
+	}
+
+	return ret;
 }
+NOKPROBE_SYMBOL(try_to_emulate);
 
-static int __kprobes kprobe_handler(struct pt_regs *regs)
+int kprobe_handler(struct pt_regs *regs)
 {
 	struct kprobe *p;
 	int ret = 0;
 	unsigned int *addr = (unsigned int *)regs->nip;
 	struct kprobe_ctlblk *kcb;
 
+	if (user_mode(regs))
+		return 0;
+
+	if (!IS_ENABLED(CONFIG_BOOKE) &&
+	    (!(regs->msr & MSR_IR) || !(regs->msr & MSR_DR)))
+		return 0;
+
 	/*
 	 * We don't want to be preempted for the entire
 	 * duration of kprobe processing
@@ -153,63 +288,21 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
 	preempt_disable();
 	kcb = get_kprobe_ctlblk();
 
-	/* Check we're not actually recursing */
-	if (kprobe_running()) {
-		p = get_kprobe(addr);
-		if (p) {
-			kprobe_opcode_t insn = *p->ainsn.insn;
-			if (kcb->kprobe_status == KPROBE_HIT_SS &&
-					is_trap(insn)) {
-				/* Turn off 'trace' bits */
-				regs->msr &= ~MSR_SINGLESTEP;
-				regs->msr |= kcb->kprobe_saved_msr;
-				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);
-			kcb->kprobe_saved_msr = regs->msr;
-			kprobes_inc_nmissed_count(p);
-			prepare_singlestep(p, regs);
-			kcb->kprobe_status = KPROBE_REENTER;
-			return 1;
-		} else {
-			if (*addr != BREAKPOINT_INSTRUCTION) {
-				/* If trap variant, then it belongs not to us */
-				kprobe_opcode_t cur_insn = *addr;
-				if (is_trap(cur_insn))
-		       			goto no_kprobe;
-				/* 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;
-			}
-			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) {
+		unsigned int instr;
+
+		if (get_kernel_nofault(instr, addr))
+			goto no_kprobe;
+
+		if (instr != BREAKPOINT_INSTRUCTION) {
 			/*
 			 * PowerPC has multiple variants of the "trap"
 			 * instruction. If the current instruction is a
 			 * trap variant, it could belong to someone else
 			 */
-			kprobe_opcode_t cur_insn = *addr;
-			if (is_trap(cur_insn))
-		       		goto no_kprobe;
+			if (is_trap(instr))
+				goto no_kprobe;
 			/*
 			 * The breakpoint instruction was removed right
 			 * after we hit it.  Another cpu has removed
@@ -223,133 +316,71 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
 		goto no_kprobe;
 	}
 
+	/* Check we're not actually recursing */
+	if (kprobe_running()) {
+		kprobe_opcode_t insn = *p->ainsn.insn;
+		if (kcb->kprobe_status == KPROBE_HIT_SS && is_trap(insn)) {
+			/* Turn off 'trace' bits */
+			regs_set_return_msr(regs,
+				(regs->msr & ~MSR_SINGLESTEP) |
+				kcb->kprobe_saved_msr);
+			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);
+		kcb->kprobe_status = KPROBE_REENTER;
+		if (p->ainsn.boostable >= 0) {
+			ret = try_to_emulate(p, regs);
+
+			if (ret > 0) {
+				restore_previous_kprobe(kcb);
+				preempt_enable();
+				return 1;
+			}
+		}
+		prepare_singlestep(p, regs);
+		return 1;
+	}
+
 	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 */
+	if (p->pre_handler && p->pre_handler(p, regs)) {
+		/* handler changed execution path, so skip ss setup */
+		reset_current_kprobe();
+		preempt_enable();
 		return 1;
+	}
 
-ss_probe:
 	if (p->ainsn.boostable >= 0) {
-		unsigned int insn = *p->ainsn.insn;
+		ret = try_to_emulate(p, regs);
 
-		/* regs->nip is also adjusted if emulate_step returns 1 */
-		ret = emulate_step(regs, insn);
 		if (ret > 0) {
-			/*
-			 * Once this instruction has been boosted
-			 * successfully, set the boostable flag
-			 */
-			if (unlikely(p->ainsn.boostable == 0))
-				p->ainsn.boostable = 1;
-
 			if (p->post_handler)
 				p->post_handler(p, regs, 0);
 
 			kcb->kprobe_status = KPROBE_HIT_SSDONE;
 			reset_current_kprobe();
-			preempt_enable_no_resched();
+			preempt_enable();
 			return 1;
-		} else if (ret < 0) {
-			/*
-			 * We don't allow kprobes on mtmsr(d)/rfi(d), etc.
-			 * So, we should never get here... but, its still
-			 * good to catch them, just in case...
-			 */
-			printk("Can't step on instruction %x\n", insn);
-			BUG();
-		} else if (ret == 0)
-			/* This instruction can't be boosted */
-			p->ainsn.boostable = -1;
+		}
 	}
 	prepare_singlestep(p, regs);
 	kcb->kprobe_status = KPROBE_HIT_SS;
 	return 1;
 
 no_kprobe:
-	preempt_enable_no_resched();
+	preempt_enable();
 	return ret;
 }
-
-/*
- * Function return probe trampoline:
- * 	- init_kprobes() establishes a probepoint here
- * 	- When the probed function returns, this probe
- * 		causes the handlers to fire
- */
-static void __used kretprobe_trampoline_holder(void)
-{
-	asm volatile(".global kretprobe_trampoline\n"
-			"kretprobe_trampoline:\n"
-			"nop\n");
-}
-
-/*
- * Called when the probe at kretprobe trampoline is hit
- */
-static int __kprobes trampoline_probe_handler(struct kprobe *p,
-						struct pt_regs *regs)
-{
-	struct kretprobe_instance *ri = NULL;
-	struct hlist_head *head, empty_rp;
-	struct hlist_node *tmp;
-	unsigned long flags, orig_ret_address = 0;
-	unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
-
-	INIT_HLIST_HEAD(&empty_rp);
-	kretprobe_hash_lock(current, &head, &flags);
-
-	/*
-	 * 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 than 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, 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, &empty_rp);
-
-		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;
-	}
-
-	kretprobe_assert(ri, orig_ret_address, trampoline_address);
-	regs->nip = orig_ret_address;
-
-	reset_current_kprobe();
-	kretprobe_hash_unlock(current, &flags);
-	preempt_enable_no_resched();
-
-	hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
-		hlist_del(&ri->hlist);
-		kfree(ri);
-	}
-	/*
-	 * 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;
-}
+NOKPROBE_SYMBOL(kprobe_handler);
 
 /*
  * Called after single-stepping.  p->addr is the address of the
@@ -359,16 +390,18 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p,
  * single-stepped a copy of the instruction.  The address of this
  * copy is p->ainsn.insn.
  */
-static int __kprobes post_kprobe_handler(struct pt_regs *regs)
+int kprobe_post_handler(struct pt_regs *regs)
 {
+	int len;
 	struct kprobe *cur = kprobe_running();
 	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 
-	if (!cur)
+	if (!cur || user_mode(regs))
 		return 0;
 
+	len = ppc_inst_len(ppc_inst_read(cur->ainsn.insn));
 	/* make sure we got here for instruction we have a kprobe on */
-	if (((unsigned long)cur->ainsn.insn + 4) != regs->nip)
+	if (((unsigned long)cur->ainsn.insn + len) != regs->nip)
 		return 0;
 
 	if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
@@ -377,8 +410,8 @@ static int __kprobes post_kprobe_handler(struct pt_regs *regs)
 	}
 
 	/* Adjust nip to after the single-stepped instruction */
-	regs->nip = (unsigned long)cur->addr + 4;
-	regs->msr |= kcb->kprobe_saved_msr;
+	regs_set_return_ip(regs, (unsigned long)cur->addr + len);
+	regs_set_return_msr(regs, regs->msr | kcb->kprobe_saved_msr);
 
 	/*Restore back the original saved kprobes variables and continue. */
 	if (kcb->kprobe_status == KPROBE_REENTER) {
@@ -387,7 +420,7 @@ static int __kprobes post_kprobe_handler(struct pt_regs *regs)
 	}
 	reset_current_kprobe();
 out:
-	preempt_enable_no_resched();
+	preempt_enable();
 
 	/*
 	 * if somebody else is singlestepping across a probe point, msr
@@ -399,8 +432,9 @@ out:
 
 	return 1;
 }
+NOKPROBE_SYMBOL(kprobe_post_handler);
 
-int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 {
 	struct kprobe *cur = kprobe_running();
 	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
@@ -416,40 +450,25 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 		 * and allow the page fault handler to continue as a
 		 * normal page fault.
 		 */
-		regs->nip = (unsigned long)cur->addr;
-		regs->msr &= ~MSR_SINGLESTEP; /* Turn off 'trace' bits */
-		regs->msr |= kcb->kprobe_saved_msr;
+		regs_set_return_ip(regs, (unsigned long)cur->addr);
+		/* Turn off 'trace' bits */
+		regs_set_return_msr(regs,
+			(regs->msr & ~MSR_SINGLESTEP) |
+			kcb->kprobe_saved_msr);
 		if (kcb->kprobe_status == KPROBE_REENTER)
 			restore_previous_kprobe(kcb);
 		else
 			reset_current_kprobe();
-		preempt_enable_no_resched();
+		preempt_enable();
 		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.
 		 */
 		if ((entry = search_exception_tables(regs->nip)) != NULL) {
-			regs->nip = entry->fixup;
+			regs_set_return_ip(regs, extable_fixup(entry));
 			return 1;
 		}
 
@@ -463,94 +482,13 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 	}
 	return 0;
 }
+NOKPROBE_SYMBOL(kprobe_fault_handler);
 
-/*
- * 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;
-
-	if (args->regs && user_mode(args->regs))
-		return ret;
-
-	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;
-	default:
-		break;
-	}
-	return ret;
-}
-
-#ifdef CONFIG_PPC64
-unsigned long arch_deref_entry_point(void *entry)
-{
-	return ((func_descr_t *)entry)->entry;
-}
-#endif
-
-int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
-{
-	struct jprobe *jp = container_of(p, struct jprobe, kp);
-	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->nip = arch_deref_entry_point(jp->entry);
-#ifdef CONFIG_PPC64
-	regs->gpr[2] = (unsigned long)(((func_descr_t *)jp->entry)->toc);
-#endif
-
-	return 1;
-}
-
-void __used __kprobes jprobe_return(void)
-{
-	asm volatile("trap" ::: "memory");
-}
-
-static void __used __kprobes jprobe_return_end(void)
-{
-};
-
-int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
-{
-	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
-	/*
-	 * FIXME - we should ideally be validating that we got here 'cos
-	 * of the "trap" in jprobe_return() above, before restoring the
-	 * saved regs...
-	 */
-	memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs));
-	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);
-}
-
-int __kprobes arch_trampoline_kprobe(struct kprobe *p)
+int arch_trampoline_kprobe(struct kprobe *p)
 {
-	if (p->addr == (kprobe_opcode_t *)&kretprobe_trampoline)
+	if (p->addr == (kprobe_opcode_t *)&arch_rethook_trampoline)
 		return 1;
 
 	return 0;
 }
+NOKPROBE_SYMBOL(arch_trampoline_kprobe);