Adding upstream version 5.10.209.upstream/5.10.209upstream

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

5 files changed, 1887 insertions, 0 deletions

diff --git a/arch/x86/kernel/kprobes/Makefile b/arch/x86/kernel/kprobes/Makefile
new file mode 100644
index 000000000..8a753432b
--- /dev/null
+++ b/arch/x86/kernel/kprobes/Makefile
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for kernel probes
+#
+
+obj-$(CONFIG_KPROBES)		+= core.o
+obj-$(CONFIG_OPTPROBES)		+= opt.o
+obj-$(CONFIG_KPROBES_ON_FTRACE)	+= ftrace.o
diff --git a/arch/x86/kernel/kprobes/common.h b/arch/x86/kernel/kprobes/common.h
new file mode 100644
index 000000000..7d3a2e2da
--- /dev/null
+++ b/arch/x86/kernel/kprobes/common.h
@@ -0,0 +1,108 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __X86_KERNEL_KPROBES_COMMON_H
+#define __X86_KERNEL_KPROBES_COMMON_H
+
+/* Kprobes and Optprobes common header */
+
+#include <asm/asm.h>
+#include <asm/frame.h>
+
+#ifdef CONFIG_X86_64
+
+#define SAVE_REGS_STRING			\
+	/* Skip cs, ip, orig_ax. */		\
+	"	subq $24, %rsp\n"		\
+	"	pushq %rdi\n"			\
+	"	pushq %rsi\n"			\
+	"	pushq %rdx\n"			\
+	"	pushq %rcx\n"			\
+	"	pushq %rax\n"			\
+	"	pushq %r8\n"			\
+	"	pushq %r9\n"			\
+	"	pushq %r10\n"			\
+	"	pushq %r11\n"			\
+	"	pushq %rbx\n"			\
+	"	pushq %rbp\n"			\
+	"	pushq %r12\n"			\
+	"	pushq %r13\n"			\
+	"	pushq %r14\n"			\
+	"	pushq %r15\n"			\
+	ENCODE_FRAME_POINTER
+
+#define RESTORE_REGS_STRING			\
+	"	popq %r15\n"			\
+	"	popq %r14\n"			\
+	"	popq %r13\n"			\
+	"	popq %r12\n"			\
+	"	popq %rbp\n"			\
+	"	popq %rbx\n"			\
+	"	popq %r11\n"			\
+	"	popq %r10\n"			\
+	"	popq %r9\n"			\
+	"	popq %r8\n"			\
+	"	popq %rax\n"			\
+	"	popq %rcx\n"			\
+	"	popq %rdx\n"			\
+	"	popq %rsi\n"			\
+	"	popq %rdi\n"			\
+	/* Skip orig_ax, ip, cs */		\
+	"	addq $24, %rsp\n"
+#else
+
+#define SAVE_REGS_STRING			\
+	/* Skip cs, ip, orig_ax and gs. */	\
+	"	subl $4*4, %esp\n"		\
+	"	pushl %fs\n"			\
+	"	pushl %es\n"			\
+	"	pushl %ds\n"			\
+	"	pushl %eax\n"			\
+	"	pushl %ebp\n"			\
+	"	pushl %edi\n"			\
+	"	pushl %esi\n"			\
+	"	pushl %edx\n"			\
+	"	pushl %ecx\n"			\
+	"	pushl %ebx\n"			\
+	ENCODE_FRAME_POINTER
+
+#define RESTORE_REGS_STRING			\
+	"	popl %ebx\n"			\
+	"	popl %ecx\n"			\
+	"	popl %edx\n"			\
+	"	popl %esi\n"			\
+	"	popl %edi\n"			\
+	"	popl %ebp\n"			\
+	"	popl %eax\n"			\
+	/* Skip ds, es, fs, gs, orig_ax, ip, and cs. */\
+	"	addl $7*4, %esp\n"
+#endif
+
+/* Ensure if the instruction can be boostable */
+extern int can_boost(struct insn *insn, void *orig_addr);
+/* Recover instruction if given address is probed */
+extern unsigned long recover_probed_instruction(kprobe_opcode_t *buf,
+					 unsigned long addr);
+/*
+ * Copy an instruction and adjust the displacement if the instruction
+ * uses the %rip-relative addressing mode.
+ */
+extern int __copy_instruction(u8 *dest, u8 *src, u8 *real, struct insn *insn);
+
+/* Generate a relative-jump/call instruction */
+extern void synthesize_reljump(void *dest, void *from, void *to);
+extern void synthesize_relcall(void *dest, void *from, void *to);
+
+#ifdef	CONFIG_OPTPROBES
+extern int setup_detour_execution(struct kprobe *p, struct pt_regs *regs, int reenter);
+extern unsigned long __recover_optprobed_insn(kprobe_opcode_t *buf, unsigned long addr);
+#else	/* !CONFIG_OPTPROBES */
+static inline int setup_detour_execution(struct kprobe *p, struct pt_regs *regs, int reenter)
+{
+	return 0;
+}
+static inline unsigned long __recover_optprobed_insn(kprobe_opcode_t *buf, unsigned long addr)
+{
+	return addr;
+}
+#endif
+
+#endif
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
new file mode 100644
index 000000000..e7edc9e4c
--- /dev/null
+++ b/arch/x86/kernel/kprobes/core.c
@@ -0,0 +1,1152 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Kernel Probes (KProbes)
+ *
+ * Copyright (C) IBM Corporation, 2002, 2004
+ *
+ * 2002-Oct	Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
+ *		Probes initial implementation ( includes contributions from
+ *		Rusty Russell).
+ * 2004-July	Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
+ *		interface to access function arguments.
+ * 2004-Oct	Jim Keniston <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
+ *		<prasanna@in.ibm.com> adapted for x86_64 from i386.
+ * 2005-Mar	Roland McGrath <roland@redhat.com>
+ *		Fixed to handle %rip-relative addressing mode correctly.
+ * 2005-May	Hien Nguyen <hien@us.ibm.com>, Jim Keniston
+ *		<jkenisto@us.ibm.com> and Prasanna S Panchamukhi
+ *		<prasanna@in.ibm.com> added function-return probes.
+ * 2005-May	Rusty Lynch <rusty.lynch@intel.com>
+ *		Added function return probes functionality
+ * 2006-Feb	Masami Hiramatsu <hiramatu@sdl.hitachi.co.jp> added
+ *		kprobe-booster and kretprobe-booster for i386.
+ * 2007-Dec	Masami Hiramatsu <mhiramat@redhat.com> added kprobe-booster
+ *		and kretprobe-booster for x86-64
+ * 2007-Dec	Masami Hiramatsu <mhiramat@redhat.com>, Arjan van de Ven
+ *		<arjan@infradead.org> and Jim Keniston <jkenisto@us.ibm.com>
+ *		unified x86 kprobes code.
+ */
+#include <linux/kprobes.h>
+#include <linux/ptrace.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/hardirq.h>
+#include <linux/preempt.h>
+#include <linux/sched/debug.h>
+#include <linux/perf_event.h>
+#include <linux/extable.h>
+#include <linux/kdebug.h>
+#include <linux/kallsyms.h>
+#include <linux/kgdb.h>
+#include <linux/ftrace.h>
+#include <linux/kasan.h>
+#include <linux/moduleloader.h>
+#include <linux/objtool.h>
+#include <linux/vmalloc.h>
+#include <linux/pgtable.h>
+
+#include <asm/text-patching.h>
+#include <asm/cacheflush.h>
+#include <asm/desc.h>
+#include <linux/uaccess.h>
+#include <asm/alternative.h>
+#include <asm/insn.h>
+#include <asm/debugreg.h>
+#include <asm/set_memory.h>
+
+#include "common.h"
+
+DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
+DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
+
+#define stack_addr(regs) ((unsigned long *)regs->sp)
+
+#define W(row, b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, ba, bb, bc, bd, be, bf)\
+	(((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) |   \
+	  (b4##UL << 0x4)|(b5##UL << 0x5)|(b6##UL << 0x6)|(b7##UL << 0x7) |   \
+	  (b8##UL << 0x8)|(b9##UL << 0x9)|(ba##UL << 0xa)|(bb##UL << 0xb) |   \
+	  (bc##UL << 0xc)|(bd##UL << 0xd)|(be##UL << 0xe)|(bf##UL << 0xf))    \
+	 << (row % 32))
+	/*
+	 * Undefined/reserved opcodes, conditional jump, Opcode Extension
+	 * Groups, and some special opcodes can not boost.
+	 * This is non-const and volatile to keep gcc from statically
+	 * optimizing it out, as variable_test_bit makes gcc think only
+	 * *(unsigned long*) is used.
+	 */
+static volatile u32 twobyte_is_boostable[256 / 32] = {
+	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */
+	/*      ----------------------------------------------          */
+	W(0x00, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0) | /* 00 */
+	W(0x10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1) , /* 10 */
+	W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 20 */
+	W(0x30, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 30 */
+	W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 40 */
+	W(0x50, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 50 */
+	W(0x60, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1) | /* 60 */
+	W(0x70, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1) , /* 70 */
+	W(0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 80 */
+	W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 90 */
+	W(0xa0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1) | /* a0 */
+	W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1) , /* b0 */
+	W(0xc0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1) | /* c0 */
+	W(0xd0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1) , /* d0 */
+	W(0xe0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1) | /* e0 */
+	W(0xf0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0, 1, 1, 1, 0)   /* f0 */
+	/*      -----------------------------------------------         */
+	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */
+};
+#undef W
+
+struct kretprobe_blackpoint kretprobe_blacklist[] = {
+	{"__switch_to", }, /* This function switches only current task, but
+			      doesn't switch kernel stack.*/
+	{NULL, NULL}	/* Terminator */
+};
+
+const int kretprobe_blacklist_size = ARRAY_SIZE(kretprobe_blacklist);
+
+static nokprobe_inline void
+__synthesize_relative_insn(void *dest, void *from, void *to, u8 op)
+{
+	struct __arch_relative_insn {
+		u8 op;
+		s32 raddr;
+	} __packed *insn;
+
+	insn = (struct __arch_relative_insn *)dest;
+	insn->raddr = (s32)((long)(to) - ((long)(from) + 5));
+	insn->op = op;
+}
+
+/* Insert a jump instruction at address 'from', which jumps to address 'to'.*/
+void synthesize_reljump(void *dest, void *from, void *to)
+{
+	__synthesize_relative_insn(dest, from, to, JMP32_INSN_OPCODE);
+}
+NOKPROBE_SYMBOL(synthesize_reljump);
+
+/* Insert a call instruction at address 'from', which calls address 'to'.*/
+void synthesize_relcall(void *dest, void *from, void *to)
+{
+	__synthesize_relative_insn(dest, from, to, CALL_INSN_OPCODE);
+}
+NOKPROBE_SYMBOL(synthesize_relcall);
+
+/*
+ * Returns non-zero if INSN is boostable.
+ * RIP relative instructions are adjusted at copying time in 64 bits mode
+ */
+int can_boost(struct insn *insn, void *addr)
+{
+	kprobe_opcode_t opcode;
+	insn_byte_t prefix;
+	int i;
+
+	if (search_exception_tables((unsigned long)addr))
+		return 0;	/* Page fault may occur on this address. */
+
+	/* 2nd-byte opcode */
+	if (insn->opcode.nbytes == 2)
+		return test_bit(insn->opcode.bytes[1],
+				(unsigned long *)twobyte_is_boostable);
+
+	if (insn->opcode.nbytes != 1)
+		return 0;
+
+	for_each_insn_prefix(insn, i, prefix) {
+		insn_attr_t attr;
+
+		attr = inat_get_opcode_attribute(prefix);
+		/* Can't boost Address-size override prefix and CS override prefix */
+		if (prefix == 0x2e || inat_is_address_size_prefix(attr))
+			return 0;
+	}
+
+	opcode = insn->opcode.bytes[0];
+
+	switch (opcode) {
+	case 0x62:		/* bound */
+	case 0x70 ... 0x7f:	/* Conditional jumps */
+	case 0x9a:		/* Call far */
+	case 0xc0 ... 0xc1:	/* Grp2 */
+	case 0xcc ... 0xce:	/* software exceptions */
+	case 0xd0 ... 0xd3:	/* Grp2 */
+	case 0xd6:		/* (UD) */
+	case 0xd8 ... 0xdf:	/* ESC */
+	case 0xe0 ... 0xe3:	/* LOOP*, JCXZ */
+	case 0xe8 ... 0xe9:	/* near Call, JMP */
+	case 0xeb:		/* Short JMP */
+	case 0xf0 ... 0xf4:	/* LOCK/REP, HLT */
+	case 0xf6 ... 0xf7:	/* Grp3 */
+	case 0xfe:		/* Grp4 */
+		/* ... are not boostable */
+		return 0;
+	case 0xff:		/* Grp5 */
+		/* Only indirect jmp is boostable */
+		return X86_MODRM_REG(insn->modrm.bytes[0]) == 4;
+	default:
+		return 1;
+	}
+}
+
+static unsigned long
+__recover_probed_insn(kprobe_opcode_t *buf, unsigned long addr)
+{
+	struct kprobe *kp;
+	unsigned long faddr;
+
+	kp = get_kprobe((void *)addr);
+	faddr = ftrace_location(addr);
+	/*
+	 * Addresses inside the ftrace location are refused by
+	 * arch_check_ftrace_location(). Something went terribly wrong
+	 * if such an address is checked here.
+	 */
+	if (WARN_ON(faddr && faddr != addr))
+		return 0UL;
+	/*
+	 * Use the current code if it is not modified by Kprobe
+	 * and it cannot be modified by ftrace.
+	 */
+	if (!kp && !faddr)
+		return addr;
+
+	/*
+	 * Basically, kp->ainsn.insn has an original instruction.
+	 * However, RIP-relative instruction can not do single-stepping
+	 * at different place, __copy_instruction() tweaks the displacement of
+	 * that instruction. In that case, we can't recover the instruction
+	 * from the kp->ainsn.insn.
+	 *
+	 * On the other hand, in case on normal Kprobe, kp->opcode has a copy
+	 * of the first byte of the probed instruction, which is overwritten
+	 * by int3. And the instruction at kp->addr is not modified by kprobes
+	 * except for the first byte, we can recover the original instruction
+	 * from it and kp->opcode.
+	 *
+	 * In case of Kprobes using ftrace, we do not have a copy of
+	 * the original instruction. In fact, the ftrace location might
+	 * be modified at anytime and even could be in an inconsistent state.
+	 * Fortunately, we know that the original code is the ideal 5-byte
+	 * long NOP.
+	 */
+	if (copy_from_kernel_nofault(buf, (void *)addr,
+		MAX_INSN_SIZE * sizeof(kprobe_opcode_t)))
+		return 0UL;
+
+	if (faddr)
+		memcpy(buf, ideal_nops[NOP_ATOMIC5], 5);
+	else
+		buf[0] = kp->opcode;
+	return (unsigned long)buf;
+}
+
+/*
+ * Recover the probed instruction at addr for further analysis.
+ * Caller must lock kprobes by kprobe_mutex, or disable preemption
+ * for preventing to release referencing kprobes.
+ * Returns zero if the instruction can not get recovered (or access failed).
+ */
+unsigned long recover_probed_instruction(kprobe_opcode_t *buf, unsigned long addr)
+{
+	unsigned long __addr;
+
+	__addr = __recover_optprobed_insn(buf, addr);
+	if (__addr != addr)
+		return __addr;
+
+	return __recover_probed_insn(buf, addr);
+}
+
+/* Check if paddr is at an instruction boundary */
+static int can_probe(unsigned long paddr)
+{
+	unsigned long addr, __addr, offset = 0;
+	struct insn insn;
+	kprobe_opcode_t buf[MAX_INSN_SIZE];
+
+	if (!kallsyms_lookup_size_offset(paddr, NULL, &offset))
+		return 0;
+
+	/* Decode instructions */
+	addr = paddr - offset;
+	while (addr < paddr) {
+		int ret;
+
+		/*
+		 * Check if the instruction has been modified by another
+		 * kprobe, in which case we replace the breakpoint by the
+		 * original instruction in our buffer.
+		 * Also, jump optimization will change the breakpoint to
+		 * relative-jump. Since the relative-jump itself is
+		 * normally used, we just go through if there is no kprobe.
+		 */
+		__addr = recover_probed_instruction(buf, addr);
+		if (!__addr)
+			return 0;
+
+		ret = insn_decode(&insn, (void *)__addr, MAX_INSN_SIZE, INSN_MODE_KERN);
+		if (ret < 0)
+			return 0;
+
+#ifdef CONFIG_KGDB
+		/*
+		 * If there is a dynamically installed kgdb sw breakpoint,
+		 * this function should not be probed.
+		 */
+		if (insn.opcode.bytes[0] == INT3_INSN_OPCODE &&
+		    kgdb_has_hit_break(addr))
+			return 0;
+#endif
+		addr += insn.length;
+	}
+
+	return (addr == paddr);
+}
+
+/*
+ * Copy an instruction with recovering modified instruction by kprobes
+ * and adjust the displacement if the instruction uses the %rip-relative
+ * addressing mode. Note that since @real will be the final place of copied
+ * instruction, displacement must be adjust by @real, not @dest.
+ * This returns the length of copied instruction, or 0 if it has an error.
+ */
+int __copy_instruction(u8 *dest, u8 *src, u8 *real, struct insn *insn)
+{
+	kprobe_opcode_t buf[MAX_INSN_SIZE];
+	unsigned long recovered_insn = recover_probed_instruction(buf, (unsigned long)src);
+	int ret;
+
+	if (!recovered_insn || !insn)
+		return 0;
+
+	/* This can access kernel text if given address is not recovered */
+	if (copy_from_kernel_nofault(dest, (void *)recovered_insn,
+			MAX_INSN_SIZE))
+		return 0;
+
+	ret = insn_decode(insn, dest, MAX_INSN_SIZE, INSN_MODE_KERN);
+	if (ret < 0)
+		return 0;
+
+	/* We can not probe force emulate prefixed instruction */
+	if (insn_has_emulate_prefix(insn))
+		return 0;
+
+	/* Another subsystem puts a breakpoint, failed to recover */
+	if (insn->opcode.bytes[0] == INT3_INSN_OPCODE)
+		return 0;
+
+	/* We should not singlestep on the exception masking instructions */
+	if (insn_masking_exception(insn))
+		return 0;
+
+#ifdef CONFIG_X86_64
+	/* Only x86_64 has RIP relative instructions */
+	if (insn_rip_relative(insn)) {
+		s64 newdisp;
+		u8 *disp;
+		/*
+		 * The copied instruction uses the %rip-relative addressing
+		 * mode.  Adjust the displacement for the difference between
+		 * the original location of this instruction and the location
+		 * of the copy that will actually be run.  The tricky bit here
+		 * is making sure that the sign extension happens correctly in
+		 * this calculation, since we need a signed 32-bit result to
+		 * be sign-extended to 64 bits when it's added to the %rip
+		 * value and yield the same 64-bit result that the sign-
+		 * extension of the original signed 32-bit displacement would
+		 * have given.
+		 */
+		newdisp = (u8 *) src + (s64) insn->displacement.value
+			  - (u8 *) real;
+		if ((s64) (s32) newdisp != newdisp) {
+			pr_err("Kprobes error: new displacement does not fit into s32 (%llx)\n", newdisp);
+			return 0;
+		}
+		disp = (u8 *) dest + insn_offset_displacement(insn);
+		*(s32 *) disp = (s32) newdisp;
+	}
+#endif
+	return insn->length;
+}
+
+/* Prepare reljump or int3 right after instruction */
+static int prepare_singlestep(kprobe_opcode_t *buf, struct kprobe *p,
+			      struct insn *insn)
+{
+	int len = insn->length;
+
+	if (!IS_ENABLED(CONFIG_PREEMPTION) &&
+	    !p->post_handler && can_boost(insn, p->addr) &&
+	    MAX_INSN_SIZE - len >= JMP32_INSN_SIZE) {
+		/*
+		 * These instructions can be executed directly if it
+		 * jumps back to correct address.
+		 */
+		synthesize_reljump(buf + len, p->ainsn.insn + len,
+				   p->addr + insn->length);
+		len += JMP32_INSN_SIZE;
+		p->ainsn.boostable = 1;
+	} else {
+		/* Otherwise, put an int3 for trapping singlestep */
+		if (MAX_INSN_SIZE - len < INT3_INSN_SIZE)
+			return -ENOSPC;
+
+		buf[len] = INT3_INSN_OPCODE;
+		len += INT3_INSN_SIZE;
+	}
+
+	return len;
+}
+
+/* Make page to RO mode when allocate it */
+void *alloc_insn_page(void)
+{
+	void *page;
+
+	page = module_alloc(PAGE_SIZE);
+	if (!page)
+		return NULL;
+
+	set_vm_flush_reset_perms(page);
+	/*
+	 * First make the page read-only, and only then make it executable to
+	 * prevent it from being W+X in between.
+	 */
+	set_memory_ro((unsigned long)page, 1);
+
+	/*
+	 * TODO: Once additional kernel code protection mechanisms are set, ensure
+	 * that the page was not maliciously altered and it is still zeroed.
+	 */
+	set_memory_x((unsigned long)page, 1);
+
+	return page;
+}
+
+/* Recover page to RW mode before releasing it */
+void free_insn_page(void *page)
+{
+	module_memfree(page);
+}
+
+/* Kprobe x86 instruction emulation - only regs->ip or IF flag modifiers */
+
+static void kprobe_emulate_ifmodifiers(struct kprobe *p, struct pt_regs *regs)
+{
+	switch (p->ainsn.opcode) {
+	case 0xfa:	/* cli */
+		regs->flags &= ~(X86_EFLAGS_IF);
+		break;
+	case 0xfb:	/* sti */
+		regs->flags |= X86_EFLAGS_IF;
+		break;
+	case 0x9c:	/* pushf */
+		int3_emulate_push(regs, regs->flags);
+		break;
+	case 0x9d:	/* popf */
+		regs->flags = int3_emulate_pop(regs);
+		break;
+	}
+	regs->ip = regs->ip - INT3_INSN_SIZE + p->ainsn.size;
+}
+NOKPROBE_SYMBOL(kprobe_emulate_ifmodifiers);
+
+static void kprobe_emulate_ret(struct kprobe *p, struct pt_regs *regs)
+{
+	int3_emulate_ret(regs);
+}
+NOKPROBE_SYMBOL(kprobe_emulate_ret);
+
+static void kprobe_emulate_call(struct kprobe *p, struct pt_regs *regs)
+{
+	unsigned long func = regs->ip - INT3_INSN_SIZE + p->ainsn.size;
+
+	func += p->ainsn.rel32;
+	int3_emulate_call(regs, func);
+}
+NOKPROBE_SYMBOL(kprobe_emulate_call);
+
+static nokprobe_inline
+void __kprobe_emulate_jmp(struct kprobe *p, struct pt_regs *regs, bool cond)
+{
+	unsigned long ip = regs->ip - INT3_INSN_SIZE + p->ainsn.size;
+
+	if (cond)
+		ip += p->ainsn.rel32;
+	int3_emulate_jmp(regs, ip);
+}
+
+static void kprobe_emulate_jmp(struct kprobe *p, struct pt_regs *regs)
+{
+	__kprobe_emulate_jmp(p, regs, true);
+}
+NOKPROBE_SYMBOL(kprobe_emulate_jmp);
+
+static const unsigned long jcc_mask[6] = {
+	[0] = X86_EFLAGS_OF,
+	[1] = X86_EFLAGS_CF,
+	[2] = X86_EFLAGS_ZF,
+	[3] = X86_EFLAGS_CF | X86_EFLAGS_ZF,
+	[4] = X86_EFLAGS_SF,
+	[5] = X86_EFLAGS_PF,
+};
+
+static void kprobe_emulate_jcc(struct kprobe *p, struct pt_regs *regs)
+{
+	bool invert = p->ainsn.jcc.type & 1;
+	bool match;
+
+	if (p->ainsn.jcc.type < 0xc) {
+		match = regs->flags & jcc_mask[p->ainsn.jcc.type >> 1];
+	} else {
+		match = ((regs->flags & X86_EFLAGS_SF) >> X86_EFLAGS_SF_BIT) ^
+			((regs->flags & X86_EFLAGS_OF) >> X86_EFLAGS_OF_BIT);
+		if (p->ainsn.jcc.type >= 0xe)
+			match = match || (regs->flags & X86_EFLAGS_ZF);
+	}
+	__kprobe_emulate_jmp(p, regs, (match && !invert) || (!match && invert));
+}
+NOKPROBE_SYMBOL(kprobe_emulate_jcc);
+
+static void kprobe_emulate_loop(struct kprobe *p, struct pt_regs *regs)
+{
+	bool match;
+
+	if (p->ainsn.loop.type != 3) {	/* LOOP* */
+		if (p->ainsn.loop.asize == 32)
+			match = ((*(u32 *)&regs->cx)--) != 0;
+#ifdef CONFIG_X86_64
+		else if (p->ainsn.loop.asize == 64)
+			match = ((*(u64 *)&regs->cx)--) != 0;
+#endif
+		else
+			match = ((*(u16 *)&regs->cx)--) != 0;
+	} else {			/* JCXZ */
+		if (p->ainsn.loop.asize == 32)
+			match = *(u32 *)(&regs->cx) == 0;
+#ifdef CONFIG_X86_64
+		else if (p->ainsn.loop.asize == 64)
+			match = *(u64 *)(&regs->cx) == 0;
+#endif
+		else
+			match = *(u16 *)(&regs->cx) == 0;
+	}
+
+	if (p->ainsn.loop.type == 0)	/* LOOPNE */
+		match = match && !(regs->flags & X86_EFLAGS_ZF);
+	else if (p->ainsn.loop.type == 1)	/* LOOPE */
+		match = match && (regs->flags & X86_EFLAGS_ZF);
+
+	__kprobe_emulate_jmp(p, regs, match);
+}
+NOKPROBE_SYMBOL(kprobe_emulate_loop);
+
+static const int addrmode_regoffs[] = {
+	offsetof(struct pt_regs, ax),
+	offsetof(struct pt_regs, cx),
+	offsetof(struct pt_regs, dx),
+	offsetof(struct pt_regs, bx),
+	offsetof(struct pt_regs, sp),
+	offsetof(struct pt_regs, bp),
+	offsetof(struct pt_regs, si),
+	offsetof(struct pt_regs, di),
+#ifdef CONFIG_X86_64
+	offsetof(struct pt_regs, r8),
+	offsetof(struct pt_regs, r9),
+	offsetof(struct pt_regs, r10),
+	offsetof(struct pt_regs, r11),
+	offsetof(struct pt_regs, r12),
+	offsetof(struct pt_regs, r13),
+	offsetof(struct pt_regs, r14),
+	offsetof(struct pt_regs, r15),
+#endif
+};
+
+static void kprobe_emulate_call_indirect(struct kprobe *p, struct pt_regs *regs)
+{
+	unsigned long offs = addrmode_regoffs[p->ainsn.indirect.reg];
+
+	int3_emulate_push(regs, regs->ip - INT3_INSN_SIZE + p->ainsn.size);
+	int3_emulate_jmp(regs, regs_get_register(regs, offs));
+}
+NOKPROBE_SYMBOL(kprobe_emulate_call_indirect);
+
+static void kprobe_emulate_jmp_indirect(struct kprobe *p, struct pt_regs *regs)
+{
+	unsigned long offs = addrmode_regoffs[p->ainsn.indirect.reg];
+
+	int3_emulate_jmp(regs, regs_get_register(regs, offs));
+}
+NOKPROBE_SYMBOL(kprobe_emulate_jmp_indirect);
+
+static int prepare_emulation(struct kprobe *p, struct insn *insn)
+{
+	insn_byte_t opcode = insn->opcode.bytes[0];
+
+	switch (opcode) {
+	case 0xfa:		/* cli */
+	case 0xfb:		/* sti */
+	case 0x9c:		/* pushfl */
+	case 0x9d:		/* popf/popfd */
+		/*
+		 * IF modifiers must be emulated since it will enable interrupt while
+		 * int3 single stepping.
+		 */
+		p->ainsn.emulate_op = kprobe_emulate_ifmodifiers;
+		p->ainsn.opcode = opcode;
+		break;
+	case 0xc2:	/* ret/lret */
+	case 0xc3:
+	case 0xca:
+	case 0xcb:
+		p->ainsn.emulate_op = kprobe_emulate_ret;
+		break;
+	case 0x9a:	/* far call absolute -- segment is not supported */
+	case 0xea:	/* far jmp absolute -- segment is not supported */
+	case 0xcc:	/* int3 */
+	case 0xcf:	/* iret -- in-kernel IRET is not supported */
+		return -EOPNOTSUPP;
+		break;
+	case 0xe8:	/* near call relative */
+		p->ainsn.emulate_op = kprobe_emulate_call;
+		if (insn->immediate.nbytes == 2)
+			p->ainsn.rel32 = *(s16 *)&insn->immediate.value;
+		else
+			p->ainsn.rel32 = *(s32 *)&insn->immediate.value;
+		break;
+	case 0xeb:	/* short jump relative */
+	case 0xe9:	/* near jump relative */
+		p->ainsn.emulate_op = kprobe_emulate_jmp;
+		if (insn->immediate.nbytes == 1)
+			p->ainsn.rel32 = *(s8 *)&insn->immediate.value;
+		else if (insn->immediate.nbytes == 2)
+			p->ainsn.rel32 = *(s16 *)&insn->immediate.value;
+		else
+			p->ainsn.rel32 = *(s32 *)&insn->immediate.value;
+		break;
+	case 0x70 ... 0x7f:
+		/* 1 byte conditional jump */
+		p->ainsn.emulate_op = kprobe_emulate_jcc;
+		p->ainsn.jcc.type = opcode & 0xf;
+		p->ainsn.rel32 = *(char *)insn->immediate.bytes;
+		break;
+	case 0x0f:
+		opcode = insn->opcode.bytes[1];
+		if ((opcode & 0xf0) == 0x80) {
+			/* 2 bytes Conditional Jump */
+			p->ainsn.emulate_op = kprobe_emulate_jcc;
+			p->ainsn.jcc.type = opcode & 0xf;
+			if (insn->immediate.nbytes == 2)
+				p->ainsn.rel32 = *(s16 *)&insn->immediate.value;
+			else
+				p->ainsn.rel32 = *(s32 *)&insn->immediate.value;
+		} else if (opcode == 0x01 &&
+			   X86_MODRM_REG(insn->modrm.bytes[0]) == 0 &&
+			   X86_MODRM_MOD(insn->modrm.bytes[0]) == 3) {
+			/* VM extensions - not supported */
+			return -EOPNOTSUPP;
+		}
+		break;
+	case 0xe0:	/* Loop NZ */
+	case 0xe1:	/* Loop */
+	case 0xe2:	/* Loop */
+	case 0xe3:	/* J*CXZ */
+		p->ainsn.emulate_op = kprobe_emulate_loop;
+		p->ainsn.loop.type = opcode & 0x3;
+		p->ainsn.loop.asize = insn->addr_bytes * 8;
+		p->ainsn.rel32 = *(s8 *)&insn->immediate.value;
+		break;
+	case 0xff:
+		/*
+		 * Since the 0xff is an extended group opcode, the instruction
+		 * is determined by the MOD/RM byte.
+		 */
+		opcode = insn->modrm.bytes[0];
+		if ((opcode & 0x30) == 0x10) {
+			if ((opcode & 0x8) == 0x8)
+				return -EOPNOTSUPP;	/* far call */
+			/* call absolute, indirect */
+			p->ainsn.emulate_op = kprobe_emulate_call_indirect;
+		} else if ((opcode & 0x30) == 0x20) {
+			if ((opcode & 0x8) == 0x8)
+				return -EOPNOTSUPP;	/* far jmp */
+			/* jmp near absolute indirect */
+			p->ainsn.emulate_op = kprobe_emulate_jmp_indirect;
+		} else
+			break;
+
+		if (insn->addr_bytes != sizeof(unsigned long))
+			return -EOPNOTSUPP;	/* Don't support differnt size */
+		if (X86_MODRM_MOD(opcode) != 3)
+			return -EOPNOTSUPP;	/* TODO: support memory addressing */
+
+		p->ainsn.indirect.reg = X86_MODRM_RM(opcode);
+#ifdef CONFIG_X86_64
+		if (X86_REX_B(insn->rex_prefix.value))
+			p->ainsn.indirect.reg += 8;
+#endif
+		break;
+	default:
+		break;
+	}
+	p->ainsn.size = insn->length;
+
+	return 0;
+}
+
+static int arch_copy_kprobe(struct kprobe *p)
+{
+	struct insn insn;
+	kprobe_opcode_t buf[MAX_INSN_SIZE];
+	int ret, len;
+
+	/* Copy an instruction with recovering if other optprobe modifies it.*/
+	len = __copy_instruction(buf, p->addr, p->ainsn.insn, &insn);
+	if (!len)
+		return -EINVAL;
+
+	/* Analyze the opcode and setup emulate functions */
+	ret = prepare_emulation(p, &insn);
+	if (ret < 0)
+		return ret;
+
+	/* Add int3 for single-step or booster jmp */
+	len = prepare_singlestep(buf, p, &insn);
+	if (len < 0)
+		return len;
+
+	/* Also, displacement change doesn't affect the first byte */
+	p->opcode = buf[0];
+
+	p->ainsn.tp_len = len;
+	perf_event_text_poke(p->ainsn.insn, NULL, 0, buf, len);
+
+	/* OK, write back the instruction(s) into ROX insn buffer */
+	text_poke(p->ainsn.insn, buf, len);
+
+	return 0;
+}
+
+int arch_prepare_kprobe(struct kprobe *p)
+{
+	int ret;
+
+	if (alternatives_text_reserved(p->addr, p->addr))
+		return -EINVAL;
+
+	if (!can_probe((unsigned long)p->addr))
+		return -EILSEQ;
+
+	memset(&p->ainsn, 0, sizeof(p->ainsn));
+
+	/* insn: must be on special executable page on x86. */
+	p->ainsn.insn = get_insn_slot();
+	if (!p->ainsn.insn)
+		return -ENOMEM;
+
+	ret = arch_copy_kprobe(p);
+	if (ret) {
+		free_insn_slot(p->ainsn.insn, 0);
+		p->ainsn.insn = NULL;
+	}
+
+	return ret;
+}
+
+void arch_arm_kprobe(struct kprobe *p)
+{
+	u8 int3 = INT3_INSN_OPCODE;
+
+	text_poke(p->addr, &int3, 1);
+	text_poke_sync();
+	perf_event_text_poke(p->addr, &p->opcode, 1, &int3, 1);
+}
+
+void arch_disarm_kprobe(struct kprobe *p)
+{
+	u8 int3 = INT3_INSN_OPCODE;
+
+	perf_event_text_poke(p->addr, &int3, 1, &p->opcode, 1);
+	text_poke(p->addr, &p->opcode, 1);
+	text_poke_sync();
+}
+
+void arch_remove_kprobe(struct kprobe *p)
+{
+	if (p->ainsn.insn) {
+		/* Record the perf event before freeing the slot */
+		perf_event_text_poke(p->ainsn.insn, p->ainsn.insn,
+				     p->ainsn.tp_len, NULL, 0);
+		free_insn_slot(p->ainsn.insn, p->ainsn.boostable);
+		p->ainsn.insn = NULL;
+	}
+}
+
+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.old_flags = kcb->kprobe_old_flags;
+	kcb->prev_kprobe.saved_flags = kcb->kprobe_saved_flags;
+}
+
+static nokprobe_inline void
+restore_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+	__this_cpu_write(current_kprobe, kcb->prev_kprobe.kp);
+	kcb->kprobe_status = kcb->prev_kprobe.status;
+	kcb->kprobe_old_flags = kcb->prev_kprobe.old_flags;
+	kcb->kprobe_saved_flags = kcb->prev_kprobe.saved_flags;
+}
+
+static nokprobe_inline void
+set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
+		   struct kprobe_ctlblk *kcb)
+{
+	__this_cpu_write(current_kprobe, p);
+	kcb->kprobe_saved_flags = kcb->kprobe_old_flags
+		= (regs->flags & X86_EFLAGS_IF);
+}
+
+void arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs)
+{
+	unsigned long *sara = stack_addr(regs);
+
+	ri->ret_addr = (kprobe_opcode_t *) *sara;
+	ri->fp = sara;
+
+	/* Replace the return addr with trampoline addr */
+	*sara = (unsigned long) &kretprobe_trampoline;
+}
+NOKPROBE_SYMBOL(arch_prepare_kretprobe);
+
+static void kprobe_post_process(struct kprobe *cur, struct pt_regs *regs,
+			       struct kprobe_ctlblk *kcb)
+{
+	/* Restore back the original saved kprobes variables and continue. */
+	if (kcb->kprobe_status == KPROBE_REENTER) {
+		/* This will restore both kcb and current_kprobe */
+		restore_previous_kprobe(kcb);
+	} else {
+		/*
+		 * Always update the kcb status because
+		 * reset_curent_kprobe() doesn't update kcb.
+		 */
+		kcb->kprobe_status = KPROBE_HIT_SSDONE;
+		if (cur->post_handler)
+			cur->post_handler(cur, regs, 0);
+		reset_current_kprobe();
+	}
+}
+NOKPROBE_SYMBOL(kprobe_post_process);
+
+static void setup_singlestep(struct kprobe *p, struct pt_regs *regs,
+			     struct kprobe_ctlblk *kcb, int reenter)
+{
+	if (setup_detour_execution(p, regs, reenter))
+		return;
+
+#if !defined(CONFIG_PREEMPTION)
+	if (p->ainsn.boostable) {
+		/* Boost up -- we can execute copied instructions directly */
+		if (!reenter)
+			reset_current_kprobe();
+		/*
+		 * Reentering boosted probe doesn't reset current_kprobe,
+		 * nor set current_kprobe, because it doesn't use single
+		 * stepping.
+		 */
+		regs->ip = (unsigned long)p->ainsn.insn;
+		return;
+	}
+#endif
+	if (reenter) {
+		save_previous_kprobe(kcb);
+		set_current_kprobe(p, regs, kcb);
+		kcb->kprobe_status = KPROBE_REENTER;
+	} else
+		kcb->kprobe_status = KPROBE_HIT_SS;
+
+	if (p->ainsn.emulate_op) {
+		p->ainsn.emulate_op(p, regs);
+		kprobe_post_process(p, regs, kcb);
+		return;
+	}
+
+	/* Disable interrupt, and set ip register on trampoline */
+	regs->flags &= ~X86_EFLAGS_IF;
+	regs->ip = (unsigned long)p->ainsn.insn;
+}
+NOKPROBE_SYMBOL(setup_singlestep);
+
+/*
+ * Called after single-stepping.  p->addr is the address of the
+ * instruction whose first byte has been replaced by the "int3"
+ * instruction.  To avoid the SMP problems that can occur when we
+ * temporarily put back the original opcode to single-step, we
+ * single-stepped a copy of the instruction.  The address of this
+ * copy is p->ainsn.insn. We also doesn't use trap, but "int3" again
+ * right after the copied instruction.
+ * Different from the trap single-step, "int3" single-step can not
+ * handle the instruction which changes the ip register, e.g. jmp,
+ * call, conditional jmp, and the instructions which changes the IF
+ * flags because interrupt must be disabled around the single-stepping.
+ * Such instructions are software emulated, but others are single-stepped
+ * using "int3".
+ *
+ * When the 2nd "int3" handled, the regs->ip and regs->flags needs to
+ * be adjusted, so that we can resume execution on correct code.
+ */
+static void resume_singlestep(struct kprobe *p, struct pt_regs *regs,
+			      struct kprobe_ctlblk *kcb)
+{
+	unsigned long copy_ip = (unsigned long)p->ainsn.insn;
+	unsigned long orig_ip = (unsigned long)p->addr;
+
+	/* Restore saved interrupt flag and ip register */
+	regs->flags |= kcb->kprobe_saved_flags;
+	/* Note that regs->ip is executed int3 so must be a step back */
+	regs->ip += (orig_ip - copy_ip) - INT3_INSN_SIZE;
+}
+NOKPROBE_SYMBOL(resume_singlestep);
+
+/*
+ * We have reentered the kprobe_handler(), since another probe was hit while
+ * within the handler. We save the original kprobes variables and just single
+ * step on the instruction of the new probe without calling any user handlers.
+ */
+static int reenter_kprobe(struct kprobe *p, struct pt_regs *regs,
+			  struct kprobe_ctlblk *kcb)
+{
+	switch (kcb->kprobe_status) {
+	case KPROBE_HIT_SSDONE:
+	case KPROBE_HIT_ACTIVE:
+	case KPROBE_HIT_SS:
+		kprobes_inc_nmissed_count(p);
+		setup_singlestep(p, regs, kcb, 1);
+		break;
+	case KPROBE_REENTER:
+		/* A probe has been hit in the codepath leading up to, or just
+		 * after, single-stepping of a probed instruction. This entire
+		 * codepath should strictly reside in .kprobes.text section.
+		 * Raise a BUG or we'll continue in an endless reentering loop
+		 * and eventually a stack overflow.
+		 */
+		pr_err("Unrecoverable kprobe detected.\n");
+		dump_kprobe(p);
+		BUG();
+	default:
+		/* impossible cases */
+		WARN_ON(1);
+		return 0;
+	}
+
+	return 1;
+}
+NOKPROBE_SYMBOL(reenter_kprobe);
+
+static nokprobe_inline int kprobe_is_ss(struct kprobe_ctlblk *kcb)
+{
+	return (kcb->kprobe_status == KPROBE_HIT_SS ||
+		kcb->kprobe_status == KPROBE_REENTER);
+}
+
+/*
+ * Interrupts are disabled on entry as trap3 is an interrupt gate and they
+ * remain disabled throughout this function.
+ */
+int kprobe_int3_handler(struct pt_regs *regs)
+{
+	kprobe_opcode_t *addr;
+	struct kprobe *p;
+	struct kprobe_ctlblk *kcb;
+
+	if (user_mode(regs))
+		return 0;
+
+	addr = (kprobe_opcode_t *)(regs->ip - sizeof(kprobe_opcode_t));
+	/*
+	 * We don't want to be preempted for the entire duration of kprobe
+	 * processing. Since int3 and debug trap disables irqs and we clear
+	 * IF while singlestepping, it must be no preemptible.
+	 */
+
+	kcb = get_kprobe_ctlblk();
+	p = get_kprobe(addr);
+
+	if (p) {
+		if (kprobe_running()) {
+			if (reenter_kprobe(p, regs, kcb))
+				return 1;
+		} else {
+			set_current_kprobe(p, regs, kcb);
+			kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+
+			/*
+			 * If we have no pre-handler or it returned 0, we
+			 * continue with normal processing.  If we have a
+			 * pre-handler and it returned non-zero, that means
+			 * user handler setup registers to exit to another
+			 * instruction, we must skip the single stepping.
+			 */
+			if (!p->pre_handler || !p->pre_handler(p, regs))
+				setup_singlestep(p, regs, kcb, 0);
+			else
+				reset_current_kprobe();
+			return 1;
+		}
+	} else if (kprobe_is_ss(kcb)) {
+		p = kprobe_running();
+		if ((unsigned long)p->ainsn.insn < regs->ip &&
+		    (unsigned long)p->ainsn.insn + MAX_INSN_SIZE > regs->ip) {
+			/* Most provably this is the second int3 for singlestep */
+			resume_singlestep(p, regs, kcb);
+			kprobe_post_process(p, regs, kcb);
+			return 1;
+		}
+	}
+
+	if (*addr != INT3_INSN_OPCODE) {
+		/*
+		 * 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.
+		 * Back up over the (now missing) int3 and run
+		 * the original instruction.
+		 */
+		regs->ip = (unsigned long)addr;
+		return 1;
+	} /* else: not a kprobe fault; let the kernel handle it */
+
+	return 0;
+}
+NOKPROBE_SYMBOL(kprobe_int3_handler);
+
+/*
+ * When a retprobed function returns, this code saves registers and
+ * calls trampoline_handler() runs, which calls the kretprobe's handler.
+ */
+asm(
+	".text\n"
+	".global kretprobe_trampoline\n"
+	".type kretprobe_trampoline, @function\n"
+	"kretprobe_trampoline:\n"
+	/* We don't bother saving the ss register */
+#ifdef CONFIG_X86_64
+	"	pushq %rsp\n"
+	"	pushfq\n"
+	SAVE_REGS_STRING
+	"	movq %rsp, %rdi\n"
+	"	call trampoline_handler\n"
+	/* Replace saved sp with true return address. */
+	"	movq %rax, 19*8(%rsp)\n"
+	RESTORE_REGS_STRING
+	"	popfq\n"
+#else
+	"	pushl %esp\n"
+	"	pushfl\n"
+	SAVE_REGS_STRING
+	"	movl %esp, %eax\n"
+	"	call trampoline_handler\n"
+	/* Replace saved sp with true return address. */
+	"	movl %eax, 15*4(%esp)\n"
+	RESTORE_REGS_STRING
+	"	popfl\n"
+#endif
+	ASM_RET
+	".size kretprobe_trampoline, .-kretprobe_trampoline\n"
+);
+NOKPROBE_SYMBOL(kretprobe_trampoline);
+STACK_FRAME_NON_STANDARD(kretprobe_trampoline);
+
+
+/*
+ * Called from kretprobe_trampoline
+ */
+__used __visible void *trampoline_handler(struct pt_regs *regs)
+{
+	/* fixup registers */
+	regs->cs = __KERNEL_CS;
+#ifdef CONFIG_X86_32
+	regs->gs = 0;
+#endif
+	regs->ip = (unsigned long)&kretprobe_trampoline;
+	regs->orig_ax = ~0UL;
+
+	return (void *)kretprobe_trampoline_handler(regs, &kretprobe_trampoline, &regs->sp);
+}
+NOKPROBE_SYMBOL(trampoline_handler);
+
+int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+{
+	struct kprobe *cur = kprobe_running();
+	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+	if (unlikely(regs->ip == (unsigned long)cur->ainsn.insn)) {
+		/* This must happen on single-stepping */
+		WARN_ON(kcb->kprobe_status != KPROBE_HIT_SS &&
+			kcb->kprobe_status != KPROBE_REENTER);
+		/*
+		 * We are here because the instruction being single
+		 * stepped caused a page fault. We reset the current
+		 * kprobe and the ip points back to the probe address
+		 * and allow the page fault handler to continue as a
+		 * normal page fault.
+		 */
+		regs->ip = (unsigned long)cur->addr;
+
+		/*
+		 * If the IF flag was set before the kprobe hit,
+		 * don't touch it:
+		 */
+		regs->flags |= kcb->kprobe_old_flags;
+
+		if (kcb->kprobe_status == KPROBE_REENTER)
+			restore_previous_kprobe(kcb);
+		else
+			reset_current_kprobe();
+	} else if (kcb->kprobe_status == KPROBE_HIT_ACTIVE ||
+		   kcb->kprobe_status == 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;
+	}
+
+	return 0;
+}
+NOKPROBE_SYMBOL(kprobe_fault_handler);
+
+int __init arch_populate_kprobe_blacklist(void)
+{
+	return kprobe_add_area_blacklist((unsigned long)__entry_text_start,
+					 (unsigned long)__entry_text_end);
+}
+
+int __init arch_init_kprobes(void)
+{
+	return 0;
+}
+
+int arch_trampoline_kprobe(struct kprobe *p)
+{
+	return 0;
+}
diff --git a/arch/x86/kernel/kprobes/ftrace.c b/arch/x86/kernel/kprobes/ftrace.c
new file mode 100644
index 000000000..681a4b36e
--- /dev/null
+++ b/arch/x86/kernel/kprobes/ftrace.c
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Dynamic Ftrace based Kprobes Optimization
+ *
+ * Copyright (C) Hitachi Ltd., 2012
+ */
+#include <linux/kprobes.h>
+#include <linux/ptrace.h>
+#include <linux/hardirq.h>
+#include <linux/preempt.h>
+#include <linux/ftrace.h>
+
+#include "common.h"
+
+/* Ftrace callback handler for kprobes -- called under preepmt disabed */
+void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
+			   struct ftrace_ops *ops, struct pt_regs *regs)
+{
+	struct kprobe *p;
+	struct kprobe_ctlblk *kcb;
+
+	/* Preempt is disabled by ftrace */
+	p = get_kprobe((kprobe_opcode_t *)ip);
+	if (unlikely(!p) || kprobe_disabled(p))
+		return;
+
+	kcb = get_kprobe_ctlblk();
+	if (kprobe_running()) {
+		kprobes_inc_nmissed_count(p);
+	} else {
+		unsigned long orig_ip = regs->ip;
+		/* Kprobe handler expects regs->ip = ip + 1 as breakpoint hit */
+		regs->ip = ip + sizeof(kprobe_opcode_t);
+
+		__this_cpu_write(current_kprobe, p);
+		kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+		if (!p->pre_handler || !p->pre_handler(p, regs)) {
+			/*
+			 * Emulate singlestep (and also recover regs->ip)
+			 * as if there is a 5byte nop
+			 */
+			regs->ip = (unsigned long)p->addr + MCOUNT_INSN_SIZE;
+			if (unlikely(p->post_handler)) {
+				kcb->kprobe_status = KPROBE_HIT_SSDONE;
+				p->post_handler(p, regs, 0);
+			}
+			regs->ip = orig_ip;
+		}
+		/*
+		 * If pre_handler returns !0, it changes regs->ip. We have to
+		 * skip emulating post_handler.
+		 */
+		__this_cpu_write(current_kprobe, NULL);
+	}
+}
+NOKPROBE_SYMBOL(kprobe_ftrace_handler);
+
+int arch_prepare_kprobe_ftrace(struct kprobe *p)
+{
+	p->ainsn.insn = NULL;
+	p->ainsn.boostable = false;
+	return 0;
+}
diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c
new file mode 100644
index 000000000..e37e5e824
--- /dev/null
+++ b/arch/x86/kernel/kprobes/opt.c
@@ -0,0 +1,556 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Kernel Probes Jump Optimization (Optprobes)
+ *
+ * Copyright (C) IBM Corporation, 2002, 2004
+ * Copyright (C) Hitachi Ltd., 2012
+ */
+#include <linux/kprobes.h>
+#include <linux/perf_event.h>
+#include <linux/ptrace.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/hardirq.h>
+#include <linux/preempt.h>
+#include <linux/extable.h>
+#include <linux/kdebug.h>
+#include <linux/kallsyms.h>
+#include <linux/kgdb.h>
+#include <linux/ftrace.h>
+#include <linux/objtool.h>
+#include <linux/pgtable.h>
+#include <linux/static_call.h>
+
+#include <asm/text-patching.h>
+#include <asm/cacheflush.h>
+#include <asm/desc.h>
+#include <linux/uaccess.h>
+#include <asm/alternative.h>
+#include <asm/insn.h>
+#include <asm/debugreg.h>
+#include <asm/set_memory.h>
+#include <asm/sections.h>
+#include <asm/nospec-branch.h>
+
+#include "common.h"
+
+unsigned long __recover_optprobed_insn(kprobe_opcode_t *buf, unsigned long addr)
+{
+	struct optimized_kprobe *op;
+	struct kprobe *kp;
+	long offs;
+	int i;
+
+	for (i = 0; i < JMP32_INSN_SIZE; i++) {
+		kp = get_kprobe((void *)addr - i);
+		/* This function only handles jump-optimized kprobe */
+		if (kp && kprobe_optimized(kp)) {
+			op = container_of(kp, struct optimized_kprobe, kp);
+			/* If op is optimized or under unoptimizing */
+			if (list_empty(&op->list) || optprobe_queued_unopt(op))
+				goto found;
+		}
+	}
+
+	return addr;
+found:
+	/*
+	 * If the kprobe can be optimized, original bytes which can be
+	 * overwritten by jump destination address. In this case, original
+	 * bytes must be recovered from op->optinsn.copied_insn buffer.
+	 */
+	if (copy_from_kernel_nofault(buf, (void *)addr,
+		MAX_INSN_SIZE * sizeof(kprobe_opcode_t)))
+		return 0UL;
+
+	if (addr == (unsigned long)kp->addr) {
+		buf[0] = kp->opcode;
+		memcpy(buf + 1, op->optinsn.copied_insn, DISP32_SIZE);
+	} else {
+		offs = addr - (unsigned long)kp->addr - 1;
+		memcpy(buf, op->optinsn.copied_insn + offs, DISP32_SIZE - offs);
+	}
+
+	return (unsigned long)buf;
+}
+
+static void synthesize_clac(kprobe_opcode_t *addr)
+{
+	/*
+	 * Can't be static_cpu_has() due to how objtool treats this feature bit.
+	 * This isn't a fast path anyway.
+	 */
+	if (!boot_cpu_has(X86_FEATURE_SMAP))
+		return;
+
+	/* Replace the NOP3 with CLAC */
+	addr[0] = 0x0f;
+	addr[1] = 0x01;
+	addr[2] = 0xca;
+}
+
+/* Insert a move instruction which sets a pointer to eax/rdi (1st arg). */
+static void synthesize_set_arg1(kprobe_opcode_t *addr, unsigned long val)
+{
+#ifdef CONFIG_X86_64
+	*addr++ = 0x48;
+	*addr++ = 0xbf;
+#else
+	*addr++ = 0xb8;
+#endif
+	*(unsigned long *)addr = val;
+}
+
+asm (
+			".pushsection .rodata\n"
+			"optprobe_template_func:\n"
+			".global optprobe_template_entry\n"
+			"optprobe_template_entry:\n"
+#ifdef CONFIG_X86_64
+			/* We don't bother saving the ss register */
+			"	pushq %rsp\n"
+			"	pushfq\n"
+			".global optprobe_template_clac\n"
+			"optprobe_template_clac:\n"
+			ASM_NOP3
+			SAVE_REGS_STRING
+			"	movq %rsp, %rsi\n"
+			".global optprobe_template_val\n"
+			"optprobe_template_val:\n"
+			ASM_NOP5
+			ASM_NOP5
+			".global optprobe_template_call\n"
+			"optprobe_template_call:\n"
+			ASM_NOP5
+			/* Move flags to rsp */
+			"	movq 18*8(%rsp), %rdx\n"
+			"	movq %rdx, 19*8(%rsp)\n"
+			RESTORE_REGS_STRING
+			/* Skip flags entry */
+			"	addq $8, %rsp\n"
+			"	popfq\n"
+#else /* CONFIG_X86_32 */
+			"	pushl %esp\n"
+			"	pushfl\n"
+			".global optprobe_template_clac\n"
+			"optprobe_template_clac:\n"
+			ASM_NOP3
+			SAVE_REGS_STRING
+			"	movl %esp, %edx\n"
+			".global optprobe_template_val\n"
+			"optprobe_template_val:\n"
+			ASM_NOP5
+			".global optprobe_template_call\n"
+			"optprobe_template_call:\n"
+			ASM_NOP5
+			/* Move flags into esp */
+			"	movl 14*4(%esp), %edx\n"
+			"	movl %edx, 15*4(%esp)\n"
+			RESTORE_REGS_STRING
+			/* Skip flags entry */
+			"	addl $4, %esp\n"
+			"	popfl\n"
+#endif
+			".global optprobe_template_end\n"
+			"optprobe_template_end:\n"
+			".popsection\n");
+
+void optprobe_template_func(void);
+STACK_FRAME_NON_STANDARD(optprobe_template_func);
+
+#define TMPL_CLAC_IDX \
+	((long)optprobe_template_clac - (long)optprobe_template_entry)
+#define TMPL_MOVE_IDX \
+	((long)optprobe_template_val - (long)optprobe_template_entry)
+#define TMPL_CALL_IDX \
+	((long)optprobe_template_call - (long)optprobe_template_entry)
+#define TMPL_END_IDX \
+	((long)optprobe_template_end - (long)optprobe_template_entry)
+
+/* Optimized kprobe call back function: called from optinsn */
+static void
+optimized_callback(struct optimized_kprobe *op, struct pt_regs *regs)
+{
+	/* This is possible if op is under delayed unoptimizing */
+	if (kprobe_disabled(&op->kp))
+		return;
+
+	preempt_disable();
+	if (kprobe_running()) {
+		kprobes_inc_nmissed_count(&op->kp);
+	} else {
+		struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+		/* Save skipped registers */
+		regs->cs = __KERNEL_CS;
+#ifdef CONFIG_X86_32
+		regs->gs = 0;
+#endif
+		regs->ip = (unsigned long)op->kp.addr + INT3_INSN_SIZE;
+		regs->orig_ax = ~0UL;
+
+		__this_cpu_write(current_kprobe, &op->kp);
+		kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+		opt_pre_handler(&op->kp, regs);
+		__this_cpu_write(current_kprobe, NULL);
+	}
+	preempt_enable();
+}
+NOKPROBE_SYMBOL(optimized_callback);
+
+static int copy_optimized_instructions(u8 *dest, u8 *src, u8 *real)
+{
+	struct insn insn;
+	int len = 0, ret;
+
+	while (len < JMP32_INSN_SIZE) {
+		ret = __copy_instruction(dest + len, src + len, real + len, &insn);
+		if (!ret || !can_boost(&insn, src + len))
+			return -EINVAL;
+		len += ret;
+	}
+	/* Check whether the address range is reserved */
+	if (ftrace_text_reserved(src, src + len - 1) ||
+	    alternatives_text_reserved(src, src + len - 1) ||
+	    jump_label_text_reserved(src, src + len - 1) ||
+	    static_call_text_reserved(src, src + len - 1))
+		return -EBUSY;
+
+	return len;
+}
+
+/* Check whether insn is indirect jump */
+static int __insn_is_indirect_jump(struct insn *insn)
+{
+	return ((insn->opcode.bytes[0] == 0xff &&
+		(X86_MODRM_REG(insn->modrm.value) & 6) == 4) || /* Jump */
+		insn->opcode.bytes[0] == 0xea);	/* Segment based jump */
+}
+
+/* Check whether insn jumps into specified address range */
+static int insn_jump_into_range(struct insn *insn, unsigned long start, int len)
+{
+	unsigned long target = 0;
+
+	switch (insn->opcode.bytes[0]) {
+	case 0xe0:	/* loopne */
+	case 0xe1:	/* loope */
+	case 0xe2:	/* loop */
+	case 0xe3:	/* jcxz */
+	case 0xe9:	/* near relative jump */
+	case 0xeb:	/* short relative jump */
+		break;
+	case 0x0f:
+		if ((insn->opcode.bytes[1] & 0xf0) == 0x80) /* jcc near */
+			break;
+		return 0;
+	default:
+		if ((insn->opcode.bytes[0] & 0xf0) == 0x70) /* jcc short */
+			break;
+		return 0;
+	}
+	target = (unsigned long)insn->next_byte + insn->immediate.value;
+
+	return (start <= target && target <= start + len);
+}
+
+static int insn_is_indirect_jump(struct insn *insn)
+{
+	int ret = __insn_is_indirect_jump(insn);
+
+#ifdef CONFIG_RETPOLINE
+	/*
+	 * Jump to x86_indirect_thunk_* is treated as an indirect jump.
+	 * Note that even with CONFIG_RETPOLINE=y, the kernel compiled with
+	 * older gcc may use indirect jump. So we add this check instead of
+	 * replace indirect-jump check.
+	 */
+	if (!ret)
+		ret = insn_jump_into_range(insn,
+				(unsigned long)__indirect_thunk_start,
+				(unsigned long)__indirect_thunk_end -
+				(unsigned long)__indirect_thunk_start);
+#endif
+	return ret;
+}
+
+/* Decode whole function to ensure any instructions don't jump into target */
+static int can_optimize(unsigned long paddr)
+{
+	unsigned long addr, size = 0, offset = 0;
+	struct insn insn;
+	kprobe_opcode_t buf[MAX_INSN_SIZE];
+
+	/* Lookup symbol including addr */
+	if (!kallsyms_lookup_size_offset(paddr, &size, &offset))
+		return 0;
+
+	/*
+	 * Do not optimize in the entry code due to the unstable
+	 * stack handling and registers setup.
+	 */
+	if (((paddr >= (unsigned long)__entry_text_start) &&
+	     (paddr <  (unsigned long)__entry_text_end)))
+		return 0;
+
+	/* Check there is enough space for a relative jump. */
+	if (size - offset < JMP32_INSN_SIZE)
+		return 0;
+
+	/* Decode instructions */
+	addr = paddr - offset;
+	while (addr < paddr - offset + size) { /* Decode until function end */
+		unsigned long recovered_insn;
+		int ret;
+
+		if (search_exception_tables(addr))
+			/*
+			 * Since some fixup code will jumps into this function,
+			 * we can't optimize kprobe in this function.
+			 */
+			return 0;
+		recovered_insn = recover_probed_instruction(buf, addr);
+		if (!recovered_insn)
+			return 0;
+
+		ret = insn_decode(&insn, (void *)recovered_insn, MAX_INSN_SIZE, INSN_MODE_KERN);
+		if (ret < 0)
+			return 0;
+#ifdef CONFIG_KGDB
+		/*
+		 * If there is a dynamically installed kgdb sw breakpoint,
+		 * this function should not be probed.
+		 */
+		if (insn.opcode.bytes[0] == INT3_INSN_OPCODE &&
+		    kgdb_has_hit_break(addr))
+			return 0;
+#endif
+		/* Recover address */
+		insn.kaddr = (void *)addr;
+		insn.next_byte = (void *)(addr + insn.length);
+		/* Check any instructions don't jump into target */
+		if (insn_is_indirect_jump(&insn) ||
+		    insn_jump_into_range(&insn, paddr + INT3_INSN_SIZE,
+					 DISP32_SIZE))
+			return 0;
+		addr += insn.length;
+	}
+
+	return 1;
+}
+
+/* Check optimized_kprobe can actually be optimized. */
+int arch_check_optimized_kprobe(struct optimized_kprobe *op)
+{
+	int i;
+	struct kprobe *p;
+
+	for (i = 1; i < op->optinsn.size; i++) {
+		p = get_kprobe(op->kp.addr + i);
+		if (p && !kprobe_disarmed(p))
+			return -EEXIST;
+	}
+
+	return 0;
+}
+
+/* Check the addr is within the optimized instructions. */
+int arch_within_optimized_kprobe(struct optimized_kprobe *op,
+				 unsigned long addr)
+{
+	return ((unsigned long)op->kp.addr <= addr &&
+		(unsigned long)op->kp.addr + op->optinsn.size > addr);
+}
+
+/* Free optimized instruction slot */
+static
+void __arch_remove_optimized_kprobe(struct optimized_kprobe *op, int dirty)
+{
+	u8 *slot = op->optinsn.insn;
+	if (slot) {
+		int len = TMPL_END_IDX + op->optinsn.size + JMP32_INSN_SIZE;
+
+		/* Record the perf event before freeing the slot */
+		if (dirty)
+			perf_event_text_poke(slot, slot, len, NULL, 0);
+
+		free_optinsn_slot(slot, dirty);
+		op->optinsn.insn = NULL;
+		op->optinsn.size = 0;
+	}
+}
+
+void arch_remove_optimized_kprobe(struct optimized_kprobe *op)
+{
+	__arch_remove_optimized_kprobe(op, 1);
+}
+
+/*
+ * Copy replacing target instructions
+ * Target instructions MUST be relocatable (checked inside)
+ * This is called when new aggr(opt)probe is allocated or reused.
+ */
+int arch_prepare_optimized_kprobe(struct optimized_kprobe *op,
+				  struct kprobe *__unused)
+{
+	u8 *buf = NULL, *slot;
+	int ret, len;
+	long rel;
+
+	if (!can_optimize((unsigned long)op->kp.addr))
+		return -EILSEQ;
+
+	buf = kzalloc(MAX_OPTINSN_SIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	op->optinsn.insn = slot = get_optinsn_slot();
+	if (!slot) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	/*
+	 * Verify if the address gap is in 2GB range, because this uses
+	 * a relative jump.
+	 */
+	rel = (long)slot - (long)op->kp.addr + JMP32_INSN_SIZE;
+	if (abs(rel) > 0x7fffffff) {
+		ret = -ERANGE;
+		goto err;
+	}
+
+	/* Copy arch-dep-instance from template */
+	memcpy(buf, optprobe_template_entry, TMPL_END_IDX);
+
+	/* Copy instructions into the out-of-line buffer */
+	ret = copy_optimized_instructions(buf + TMPL_END_IDX, op->kp.addr,
+					  slot + TMPL_END_IDX);
+	if (ret < 0)
+		goto err;
+	op->optinsn.size = ret;
+	len = TMPL_END_IDX + op->optinsn.size;
+
+	synthesize_clac(buf + TMPL_CLAC_IDX);
+
+	/* Set probe information */
+	synthesize_set_arg1(buf + TMPL_MOVE_IDX, (unsigned long)op);
+
+	/* Set probe function call */
+	synthesize_relcall(buf + TMPL_CALL_IDX,
+			   slot + TMPL_CALL_IDX, optimized_callback);
+
+	/* Set returning jmp instruction at the tail of out-of-line buffer */
+	synthesize_reljump(buf + len, slot + len,
+			   (u8 *)op->kp.addr + op->optinsn.size);
+	len += JMP32_INSN_SIZE;
+
+	/*
+	 * Note	len = TMPL_END_IDX + op->optinsn.size + JMP32_INSN_SIZE is also
+	 * used in __arch_remove_optimized_kprobe().
+	 */
+
+	/* We have to use text_poke() for instruction buffer because it is RO */
+	perf_event_text_poke(slot, NULL, 0, buf, len);
+	text_poke(slot, buf, len);
+
+	ret = 0;
+out:
+	kfree(buf);
+	return ret;
+
+err:
+	__arch_remove_optimized_kprobe(op, 0);
+	goto out;
+}
+
+/*
+ * Replace breakpoints (INT3) with relative jumps (JMP.d32).
+ * Caller must call with locking kprobe_mutex and text_mutex.
+ *
+ * The caller will have installed a regular kprobe and after that issued
+ * syncrhonize_rcu_tasks(), this ensures that the instruction(s) that live in
+ * the 4 bytes after the INT3 are unused and can now be overwritten.
+ */
+void arch_optimize_kprobes(struct list_head *oplist)
+{
+	struct optimized_kprobe *op, *tmp;
+	u8 insn_buff[JMP32_INSN_SIZE];
+
+	list_for_each_entry_safe(op, tmp, oplist, list) {
+		s32 rel = (s32)((long)op->optinsn.insn -
+			((long)op->kp.addr + JMP32_INSN_SIZE));
+
+		WARN_ON(kprobe_disabled(&op->kp));
+
+		/* Backup instructions which will be replaced by jump address */
+		memcpy(op->optinsn.copied_insn, op->kp.addr + INT3_INSN_SIZE,
+		       DISP32_SIZE);
+
+		insn_buff[0] = JMP32_INSN_OPCODE;
+		*(s32 *)(&insn_buff[1]) = rel;
+
+		text_poke_bp(op->kp.addr, insn_buff, JMP32_INSN_SIZE, NULL);
+
+		list_del_init(&op->list);
+	}
+}
+
+/*
+ * Replace a relative jump (JMP.d32) with a breakpoint (INT3).
+ *
+ * After that, we can restore the 4 bytes after the INT3 to undo what
+ * arch_optimize_kprobes() scribbled. This is safe since those bytes will be
+ * unused once the INT3 lands.
+ */
+void arch_unoptimize_kprobe(struct optimized_kprobe *op)
+{
+	u8 new[JMP32_INSN_SIZE] = { INT3_INSN_OPCODE, };
+	u8 old[JMP32_INSN_SIZE];
+	u8 *addr = op->kp.addr;
+
+	memcpy(old, op->kp.addr, JMP32_INSN_SIZE);
+	memcpy(new + INT3_INSN_SIZE,
+	       op->optinsn.copied_insn,
+	       JMP32_INSN_SIZE - INT3_INSN_SIZE);
+
+	text_poke(addr, new, INT3_INSN_SIZE);
+	text_poke_sync();
+	text_poke(addr + INT3_INSN_SIZE,
+		  new + INT3_INSN_SIZE,
+		  JMP32_INSN_SIZE - INT3_INSN_SIZE);
+	text_poke_sync();
+
+	perf_event_text_poke(op->kp.addr, old, JMP32_INSN_SIZE, new, JMP32_INSN_SIZE);
+}
+
+/*
+ * Recover original instructions and breakpoints from relative jumps.
+ * Caller must call with locking kprobe_mutex.
+ */
+extern void arch_unoptimize_kprobes(struct list_head *oplist,
+				    struct list_head *done_list)
+{
+	struct optimized_kprobe *op, *tmp;
+
+	list_for_each_entry_safe(op, tmp, oplist, list) {
+		arch_unoptimize_kprobe(op);
+		list_move(&op->list, done_list);
+	}
+}
+
+int setup_detour_execution(struct kprobe *p, struct pt_regs *regs, int reenter)
+{
+	struct optimized_kprobe *op;
+
+	if (p->flags & KPROBE_FLAG_OPTIMIZED) {
+		/* This kprobe is really able to run optimized path. */
+		op = container_of(p, struct optimized_kprobe, kp);
+		/* Detour through copied instructions */
+		regs->ip = (unsigned long)op->optinsn.insn + TMPL_END_IDX;
+		if (!reenter)
+			reset_current_kprobe();
+		return 1;
+	}
+	return 0;
+}
+NOKPROBE_SYMBOL(setup_detour_execution);