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

 /*
  * arch/arm/kernel/kprobes-thumb.c
  *
  * Copyright (C) 2011 Jon Medhurst <tixy@yxit.co.uk>.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */

 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/ptrace.h>
 #include <linux/kprobes.h>

 #include "kprobes.h"
 #include "probes-thumb.h"

 /* These emulation encodings are functionally equivalent... */
 #define t32_emulate_rd8rn16rm0ra12_noflags \
 		t32_emulate_rdlo12rdhi8rn16rm0_noflags

 /* t32 thumb actions */

 static void __kprobes
 t32_simulate_table_branch(probes_opcode_t insn,
 		struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	unsigned long pc = regs->ARM_pc;
 	int rn = (insn >> 16) & 0xf;
 	int rm = insn & 0xf;

 	unsigned long rnv = (rn == 15) ? pc : regs->uregs[rn];
 	unsigned long rmv = regs->uregs[rm];
 	unsigned int halfwords;

 	if (insn & 0x10) /* TBH */
 		halfwords = ((u16 *)rnv)[rmv];
 	else /* TBB */
 		halfwords = ((u8 *)rnv)[rmv];

 	regs->ARM_pc = pc + 2 * halfwords;
 }

 static void __kprobes
 t32_simulate_mrs(probes_opcode_t insn,
 		struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	int rd = (insn >> 8) & 0xf;
 	unsigned long mask = 0xf8ff03df; /* Mask out execution state */
 	regs->uregs[rd] = regs->ARM_cpsr & mask;
 }

 static void __kprobes
 t32_simulate_cond_branch(probes_opcode_t insn,
 		struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	unsigned long pc = regs->ARM_pc;

 	long offset = insn & 0x7ff;		/* imm11 */
 	offset += (insn & 0x003f0000) >> 5;	/* imm6 */
 	offset += (insn & 0x00002000) << 4;	/* J1 */
 	offset += (insn & 0x00000800) << 7;	/* J2 */
 	offset -= (insn & 0x04000000) >> 7;	/* Apply sign bit */

 	regs->ARM_pc = pc + (offset * 2);
 }

 static enum probes_insn __kprobes
 t32_decode_cond_branch(probes_opcode_t insn, struct arch_probes_insn *asi,
 		const struct decode_header *d)
 {
 	int cc = (insn >> 22) & 0xf;
 	asi->insn_check_cc = probes_condition_checks[cc];
 	asi->insn_handler = t32_simulate_cond_branch;
 	return INSN_GOOD_NO_SLOT;
 }

 static void __kprobes
 t32_simulate_branch(probes_opcode_t insn,
 		    struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	unsigned long pc = regs->ARM_pc;

 	long offset = insn & 0x7ff;		/* imm11 */
 	offset += (insn & 0x03ff0000) >> 5;	/* imm10 */
 	offset += (insn & 0x00002000) << 9;	/* J1 */
 	offset += (insn & 0x00000800) << 10;	/* J2 */
 	if (insn & 0x04000000)
 		offset -= 0x00800000; /* Apply sign bit */
 	else
 		offset ^= 0x00600000; /* Invert J1 and J2 */

 	if (insn & (1 << 14)) {
 		/* BL or BLX */
 		regs->ARM_lr = regs->ARM_pc | 1;
 		if (!(insn & (1 << 12))) {
 			/* BLX so switch to ARM mode */
 			regs->ARM_cpsr &= ~PSR_T_BIT;
 			pc &= ~3;
 		}
 	}

 	regs->ARM_pc = pc + (offset * 2);
 }

 static void __kprobes
 t32_simulate_ldr_literal(probes_opcode_t insn,
 		struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	unsigned long addr = regs->ARM_pc & ~3;
 	int rt = (insn >> 12) & 0xf;
 	unsigned long rtv;

 	long offset = insn & 0xfff;
 	if (insn & 0x00800000)
 		addr += offset;
 	else
 		addr -= offset;

 	if (insn & 0x00400000) {
 		/* LDR */
 		rtv = *(unsigned long *)addr;
 		if (rt == 15) {
 			bx_write_pc(rtv, regs);
 			return;
 		}
 	} else if (insn & 0x00200000) {
 		/* LDRH */
 		if (insn & 0x01000000)
 			rtv = *(s16 *)addr;
 		else
 			rtv = *(u16 *)addr;
 	} else {
 		/* LDRB */
 		if (insn & 0x01000000)
 			rtv = *(s8 *)addr;
 		else
 			rtv = *(u8 *)addr;
 	}

 	regs->uregs[rt] = rtv;
 }

 static enum probes_insn __kprobes
 t32_decode_ldmstm(probes_opcode_t insn, struct arch_probes_insn *asi,
 		const struct decode_header *d)
 {
 	enum probes_insn ret = kprobe_decode_ldmstm(insn, asi, d);

 	/* Fixup modified instruction to have halfwords in correct order...*/
 	insn = __mem_to_opcode_arm(asi->insn[0]);
 	((u16 *)asi->insn)[0] = __opcode_to_mem_thumb16(insn >> 16);
 	((u16 *)asi->insn)[1] = __opcode_to_mem_thumb16(insn & 0xffff);

 	return ret;
 }

 static void __kprobes
 t32_emulate_ldrdstrd(probes_opcode_t insn,
 		struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	unsigned long pc = regs->ARM_pc & ~3;
 	int rt1 = (insn >> 12) & 0xf;
 	int rt2 = (insn >> 8) & 0xf;
 	int rn = (insn >> 16) & 0xf;

 	register unsigned long rt1v asm("r0") = regs->uregs[rt1];
 	register unsigned long rt2v asm("r1") = regs->uregs[rt2];
 	register unsigned long rnv asm("r2") = (rn == 15) ? pc
 							  : regs->uregs[rn];

 	__asm__ __volatile__ (
 		"blx    %[fn]"
 		: "=r" (rt1v), "=r" (rt2v), "=r" (rnv)
 		: "0" (rt1v), "1" (rt2v), "2" (rnv), [fn] "r" (asi->insn_fn)
 		: "lr", "memory", "cc"
 	);

 	if (rn != 15)
 		regs->uregs[rn] = rnv; /* Writeback base register */
 	regs->uregs[rt1] = rt1v;
 	regs->uregs[rt2] = rt2v;
 }

 static void __kprobes
 t32_emulate_ldrstr(probes_opcode_t insn,
 		struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	int rt = (insn >> 12) & 0xf;
 	int rn = (insn >> 16) & 0xf;
 	int rm = insn & 0xf;

 	register unsigned long rtv asm("r0") = regs->uregs[rt];
 	register unsigned long rnv asm("r2") = regs->uregs[rn];
 	register unsigned long rmv asm("r3") = regs->uregs[rm];

 	__asm__ __volatile__ (
 		"blx    %[fn]"
 		: "=r" (rtv), "=r" (rnv)
 		: "0" (rtv), "1" (rnv), "r" (rmv), [fn] "r" (asi->insn_fn)
 		: "lr", "memory", "cc"
 	);

 	regs->uregs[rn] = rnv; /* Writeback base register */
 	if (rt == 15) /* Can't be true for a STR as they aren't allowed */
 		bx_write_pc(rtv, regs);
 	else
 		regs->uregs[rt] = rtv;
 }

 static void __kprobes
 t32_emulate_rd8rn16rm0_rwflags(probes_opcode_t insn,
 		struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	int rd = (insn >> 8) & 0xf;
 	int rn = (insn >> 16) & 0xf;
 	int rm = insn & 0xf;

 	register unsigned long rdv asm("r1") = regs->uregs[rd];
 	register unsigned long rnv asm("r2") = regs->uregs[rn];
 	register unsigned long rmv asm("r3") = regs->uregs[rm];
 	unsigned long cpsr = regs->ARM_cpsr;

 	__asm__ __volatile__ (
 		"msr	cpsr_fs, %[cpsr]	\n\t"
 		"blx    %[fn]			\n\t"
 		"mrs	%[cpsr], cpsr		\n\t"
 		: "=r" (rdv), [cpsr] "=r" (cpsr)
 		: "0" (rdv), "r" (rnv), "r" (rmv),
 		  "1" (cpsr), [fn] "r" (asi->insn_fn)
 		: "lr", "memory", "cc"
 	);

 	regs->uregs[rd] = rdv;
 	regs->ARM_cpsr = (regs->ARM_cpsr & ~APSR_MASK) | (cpsr & APSR_MASK);
 }

 static void __kprobes
 t32_emulate_rd8pc16_noflags(probes_opcode_t insn,
 		struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	unsigned long pc = regs->ARM_pc;
 	int rd = (insn >> 8) & 0xf;

 	register unsigned long rdv asm("r1") = regs->uregs[rd];
 	register unsigned long rnv asm("r2") = pc & ~3;

 	__asm__ __volatile__ (
 		"blx    %[fn]"
 		: "=r" (rdv)
 		: "0" (rdv), "r" (rnv), [fn] "r" (asi->insn_fn)
 		: "lr", "memory", "cc"
 	);

 	regs->uregs[rd] = rdv;
 }

 static void __kprobes
 t32_emulate_rd8rn16_noflags(probes_opcode_t insn,
 		struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	int rd = (insn >> 8) & 0xf;
 	int rn = (insn >> 16) & 0xf;

 	register unsigned long rdv asm("r1") = regs->uregs[rd];
 	register unsigned long rnv asm("r2") = regs->uregs[rn];

 	__asm__ __volatile__ (
 		"blx    %[fn]"
 		: "=r" (rdv)
 		: "0" (rdv), "r" (rnv), [fn] "r" (asi->insn_fn)
 		: "lr", "memory", "cc"
 	);

 	regs->uregs[rd] = rdv;
 }

 static void __kprobes
 t32_emulate_rdlo12rdhi8rn16rm0_noflags(probes_opcode_t insn,
 		struct arch_probes_insn *asi,
 		struct pt_regs *regs)
 {
 	int rdlo = (insn >> 12) & 0xf;
 	int rdhi = (insn >> 8) & 0xf;
 	int rn = (insn >> 16) & 0xf;
 	int rm = insn & 0xf;

 	register unsigned long rdlov asm("r0") = regs->uregs[rdlo];
 	register unsigned long rdhiv asm("r1") = regs->uregs[rdhi];
 	register unsigned long rnv asm("r2") = regs->uregs[rn];
 	register unsigned long rmv asm("r3") = regs->uregs[rm];

 	__asm__ __volatile__ (
 		"blx    %[fn]"
 		: "=r" (rdlov), "=r" (rdhiv)
 		: "0" (rdlov), "1" (rdhiv), "r" (rnv), "r" (rmv),
 		  [fn] "r" (asi->insn_fn)
 		: "lr", "memory", "cc"
 	);

 	regs->uregs[rdlo] = rdlov;
 	regs->uregs[rdhi] = rdhiv;
 }
 /* t16 thumb actions */

 static void __kprobes
 t16_simulate_bxblx(probes_opcode_t insn,
 		struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	unsigned long pc = regs->ARM_pc + 2;
 	int rm = (insn >> 3) & 0xf;
 	unsigned long rmv = (rm == 15) ? pc : regs->uregs[rm];

 	if (insn & (1 << 7)) /* BLX ? */
 		regs->ARM_lr = regs->ARM_pc | 1;

 	bx_write_pc(rmv, regs);
 }

 static void __kprobes
 t16_simulate_ldr_literal(probes_opcode_t insn,
 		struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	unsigned long *base = (unsigned long *)((regs->ARM_pc + 2) & ~3);
 	long index = insn & 0xff;
 	int rt = (insn >> 8) & 0x7;
 	regs->uregs[rt] = base[index];
 }

 static void __kprobes
 t16_simulate_ldrstr_sp_relative(probes_opcode_t insn,
 		struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	unsigned long* base = (unsigned long *)regs->ARM_sp;
 	long index = insn & 0xff;
 	int rt = (insn >> 8) & 0x7;
 	if (insn & 0x800) /* LDR */
 		regs->uregs[rt] = base[index];
 	else /* STR */
 		base[index] = regs->uregs[rt];
 }

 static void __kprobes
 t16_simulate_reladr(probes_opcode_t insn,
 		struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	unsigned long base = (insn & 0x800) ? regs->ARM_sp
 					    : ((regs->ARM_pc + 2) & ~3);
 	long offset = insn & 0xff;
 	int rt = (insn >> 8) & 0x7;
 	regs->uregs[rt] = base + offset * 4;
 }

 static void __kprobes
 t16_simulate_add_sp_imm(probes_opcode_t insn,
 		struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	long imm = insn & 0x7f;
 	if (insn & 0x80) /* SUB */
 		regs->ARM_sp -= imm * 4;
 	else /* ADD */
 		regs->ARM_sp += imm * 4;
 }

 static void __kprobes
 t16_simulate_cbz(probes_opcode_t insn,
 		struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	int rn = insn & 0x7;
 	probes_opcode_t nonzero = regs->uregs[rn] ? insn : ~insn;
 	if (nonzero & 0x800) {
 		long i = insn & 0x200;
 		long imm5 = insn & 0xf8;
 		unsigned long pc = regs->ARM_pc + 2;
 		regs->ARM_pc = pc + (i >> 3) + (imm5 >> 2);
 	}
 }

 static void __kprobes
 t16_simulate_it(probes_opcode_t insn,
 		struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	/*
 	 * The 8 IT state bits are split into two parts in CPSR:
 	 *	ITSTATE<1:0> are in CPSR<26:25>
 	 *	ITSTATE<7:2> are in CPSR<15:10>
 	 * The new IT state is in the lower byte of insn.
 	 */
 	unsigned long cpsr = regs->ARM_cpsr;
 	cpsr &= ~PSR_IT_MASK;
 	cpsr |= (insn & 0xfc) << 8;
 	cpsr |= (insn & 0x03) << 25;
 	regs->ARM_cpsr = cpsr;
 }

 static void __kprobes
 t16_singlestep_it(probes_opcode_t insn,
 		  struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	regs->ARM_pc += 2;
 	t16_simulate_it(insn, asi, regs);
 }

 static enum probes_insn __kprobes
 t16_decode_it(probes_opcode_t insn, struct arch_probes_insn *asi,
 		const struct decode_header *d)
 {
 	asi->insn_singlestep = t16_singlestep_it;
 	return INSN_GOOD_NO_SLOT;
 }

 static void __kprobes
 t16_simulate_cond_branch(probes_opcode_t insn,
 		struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	unsigned long pc = regs->ARM_pc + 2;
 	long offset = insn & 0x7f;
 	offset -= insn & 0x80; /* Apply sign bit */
 	regs->ARM_pc = pc + (offset * 2);
 }

 static enum probes_insn __kprobes
 t16_decode_cond_branch(probes_opcode_t insn, struct arch_probes_insn *asi,
 		const struct decode_header *d)
 {
 	int cc = (insn >> 8) & 0xf;
 	asi->insn_check_cc = probes_condition_checks[cc];
 	asi->insn_handler = t16_simulate_cond_branch;
 	return INSN_GOOD_NO_SLOT;
 }

 static void __kprobes
 t16_simulate_branch(probes_opcode_t insn,
 		   struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	unsigned long pc = regs->ARM_pc + 2;
 	long offset = insn & 0x3ff;
 	offset -= insn & 0x400; /* Apply sign bit */
 	regs->ARM_pc = pc + (offset * 2);
 }

 static unsigned long __kprobes
 t16_emulate_loregs(probes_opcode_t insn,
 		   struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	unsigned long oldcpsr = regs->ARM_cpsr;
 	unsigned long newcpsr;

 	__asm__ __volatile__ (
 		"msr	cpsr_fs, %[oldcpsr]	\n\t"
 		"ldmia	%[regs], {r0-r7}	\n\t"
 		"blx	%[fn]			\n\t"
 		"stmia	%[regs], {r0-r7}	\n\t"
 		"mrs	%[newcpsr], cpsr	\n\t"
 		: [newcpsr] "=r" (newcpsr)
 		: [oldcpsr] "r" (oldcpsr), [regs] "r" (regs),
 		  [fn] "r" (asi->insn_fn)
 		: "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
 		  "lr", "memory", "cc"
 		);

 	return (oldcpsr & ~APSR_MASK) | (newcpsr & APSR_MASK);
 }

 static void __kprobes
 t16_emulate_loregs_rwflags(probes_opcode_t insn,
 		struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	regs->ARM_cpsr = t16_emulate_loregs(insn, asi, regs);
 }

 static void __kprobes
 t16_emulate_loregs_noitrwflags(probes_opcode_t insn,
 		struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	unsigned long cpsr = t16_emulate_loregs(insn, asi, regs);
 	if (!in_it_block(cpsr))
 		regs->ARM_cpsr = cpsr;
 }

 static void __kprobes
 t16_emulate_hiregs(probes_opcode_t insn,
 		struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	unsigned long pc = regs->ARM_pc + 2;
 	int rdn = (insn & 0x7) | ((insn & 0x80) >> 4);
 	int rm = (insn >> 3) & 0xf;

 	register unsigned long rdnv asm("r1");
 	register unsigned long rmv asm("r0");
 	unsigned long cpsr = regs->ARM_cpsr;

 	rdnv = (rdn == 15) ? pc : regs->uregs[rdn];
 	rmv = (rm == 15) ? pc : regs->uregs[rm];

 	__asm__ __volatile__ (
 		"msr	cpsr_fs, %[cpsr]	\n\t"
 		"blx    %[fn]			\n\t"
 		"mrs	%[cpsr], cpsr		\n\t"
 		: "=r" (rdnv), [cpsr] "=r" (cpsr)
 		: "0" (rdnv), "r" (rmv), "1" (cpsr), [fn] "r" (asi->insn_fn)
 		: "lr", "memory", "cc"
 	);

 	if (rdn == 15)
 		rdnv &= ~1;

 	regs->uregs[rdn] = rdnv;
 	regs->ARM_cpsr = (regs->ARM_cpsr & ~APSR_MASK) | (cpsr & APSR_MASK);
 }

 static enum probes_insn __kprobes
 t16_decode_hiregs(probes_opcode_t insn, struct arch_probes_insn *asi,
 		const struct decode_header *d)
 {
 	insn &= ~0x00ff;
 	insn |= 0x001; /* Set Rdn = R1 and Rm = R0 */
 	((u16 *)asi->insn)[0] = __opcode_to_mem_thumb16(insn);
 	asi->insn_handler = t16_emulate_hiregs;
 	return INSN_GOOD;
 }

 static void __kprobes
 t16_emulate_push(probes_opcode_t insn,
 		struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	__asm__ __volatile__ (
 		"ldr	r9, [%[regs], #13*4]	\n\t"
 		"ldr	r8, [%[regs], #14*4]	\n\t"
 		"ldmia	%[regs], {r0-r7}	\n\t"
 		"blx	%[fn]			\n\t"
 		"str	r9, [%[regs], #13*4]	\n\t"
 		:
 		: [regs] "r" (regs), [fn] "r" (asi->insn_fn)
 		: "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", "r8", "r9",
 		  "lr", "memory", "cc"
 		);
 }

 static enum probes_insn __kprobes
 t16_decode_push(probes_opcode_t insn, struct arch_probes_insn *asi,
 		const struct decode_header *d)
 {
 	/*
 	 * To simulate a PUSH we use a Thumb-2 "STMDB R9!, {registers}"
 	 * and call it with R9=SP and LR in the register list represented
 	 * by R8.
 	 */
 	/* 1st half STMDB R9!,{} */
 	((u16 *)asi->insn)[0] = __opcode_to_mem_thumb16(0xe929);
 	/* 2nd half (register list) */
 	((u16 *)asi->insn)[1] = __opcode_to_mem_thumb16(insn & 0x1ff);
 	asi->insn_handler = t16_emulate_push;
 	return INSN_GOOD;
 }

 static void __kprobes
 t16_emulate_pop_nopc(probes_opcode_t insn,
 		struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	__asm__ __volatile__ (
 		"ldr	r9, [%[regs], #13*4]	\n\t"
 		"ldmia	%[regs], {r0-r7}	\n\t"
 		"blx	%[fn]			\n\t"
 		"stmia	%[regs], {r0-r7}	\n\t"
 		"str	r9, [%[regs], #13*4]	\n\t"
 		:
 		: [regs] "r" (regs), [fn] "r" (asi->insn_fn)
 		: "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", "r9",
 		  "lr", "memory", "cc"
 		);
 }

 static void __kprobes
 t16_emulate_pop_pc(probes_opcode_t insn,
 		struct arch_probes_insn *asi, struct pt_regs *regs)
 {
 	register unsigned long pc asm("r8");

 	__asm__ __volatile__ (
 		"ldr	r9, [%[regs], #13*4]	\n\t"
 		"ldmia	%[regs], {r0-r7}	\n\t"
 		"blx	%[fn]			\n\t"
 		"stmia	%[regs], {r0-r7}	\n\t"
 		"str	r9, [%[regs], #13*4]	\n\t"
 		: "=r" (pc)
 		: [regs] "r" (regs), [fn] "r" (asi->insn_fn)
 		: "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", "r9",
 		  "lr", "memory", "cc"
 		);

 	bx_write_pc(pc, regs);
 }

 static enum probes_insn __kprobes
 t16_decode_pop(probes_opcode_t insn, struct arch_probes_insn *asi,
 		const struct decode_header *d)
 {
 	/*
 	 * To simulate a POP we use a Thumb-2 "LDMDB R9!, {registers}"
 	 * and call it with R9=SP and PC in the register list represented
 	 * by R8.
 	 */
 	/* 1st half LDMIA R9!,{} */
 	((u16 *)asi->insn)[0] = __opcode_to_mem_thumb16(0xe8b9);
 	/* 2nd half (register list) */
 	((u16 *)asi->insn)[1] = __opcode_to_mem_thumb16(insn & 0x1ff);
 	asi->insn_handler = insn & 0x100 ? t16_emulate_pop_pc
 					 : t16_emulate_pop_nopc;
 	return INSN_GOOD;
 }

 const union decode_action kprobes_t16_actions[NUM_PROBES_T16_ACTIONS] = {
 	[PROBES_T16_ADD_SP] = {.handler = t16_simulate_add_sp_imm},
 	[PROBES_T16_CBZ] = {.handler = t16_simulate_cbz},
 	[PROBES_T16_SIGN_EXTEND] = {.handler = t16_emulate_loregs_rwflags},
 	[PROBES_T16_PUSH] = {.decoder = t16_decode_push},
 	[PROBES_T16_POP] = {.decoder = t16_decode_pop},
 	[PROBES_T16_SEV] = {.handler = probes_emulate_none},
 	[PROBES_T16_WFE] = {.handler = probes_simulate_nop},
 	[PROBES_T16_IT] = {.decoder = t16_decode_it},
 	[PROBES_T16_CMP] = {.handler = t16_emulate_loregs_rwflags},
 	[PROBES_T16_ADDSUB] = {.handler = t16_emulate_loregs_noitrwflags},
 	[PROBES_T16_LOGICAL] = {.handler = t16_emulate_loregs_noitrwflags},
 	[PROBES_T16_LDR_LIT] = {.handler = t16_simulate_ldr_literal},
 	[PROBES_T16_BLX] = {.handler = t16_simulate_bxblx},
 	[PROBES_T16_HIREGOPS] = {.decoder = t16_decode_hiregs},
 	[PROBES_T16_LDRHSTRH] = {.handler = t16_emulate_loregs_rwflags},
 	[PROBES_T16_LDRSTR] = {.handler = t16_simulate_ldrstr_sp_relative},
 	[PROBES_T16_ADR] = {.handler = t16_simulate_reladr},
 	[PROBES_T16_LDMSTM] = {.handler = t16_emulate_loregs_rwflags},
 	[PROBES_T16_BRANCH_COND] = {.decoder = t16_decode_cond_branch},
 	[PROBES_T16_BRANCH] = {.handler = t16_simulate_branch},
 };

 const union decode_action kprobes_t32_actions[NUM_PROBES_T32_ACTIONS] = {
 	[PROBES_T32_LDMSTM] = {.decoder = t32_decode_ldmstm},
 	[PROBES_T32_LDRDSTRD] = {.handler = t32_emulate_ldrdstrd},
 	[PROBES_T32_TABLE_BRANCH] = {.handler = t32_simulate_table_branch},
 	[PROBES_T32_TST] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
 	[PROBES_T32_MOV] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
 	[PROBES_T32_ADDSUB] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
 	[PROBES_T32_LOGICAL] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
 	[PROBES_T32_CMP] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
 	[PROBES_T32_ADDWSUBW_PC] = {.handler = t32_emulate_rd8pc16_noflags,},
 	[PROBES_T32_ADDWSUBW] = {.handler = t32_emulate_rd8rn16_noflags},
 	[PROBES_T32_MOVW] = {.handler = t32_emulate_rd8rn16_noflags},
 	[PROBES_T32_SAT] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
 	[PROBES_T32_BITFIELD] = {.handler = t32_emulate_rd8rn16_noflags},
 	[PROBES_T32_SEV] = {.handler = probes_emulate_none},
 	[PROBES_T32_WFE] = {.handler = probes_simulate_nop},
 	[PROBES_T32_MRS] = {.handler = t32_simulate_mrs},
 	[PROBES_T32_BRANCH_COND] = {.decoder = t32_decode_cond_branch},
 	[PROBES_T32_BRANCH] = {.handler = t32_simulate_branch},
 	[PROBES_T32_PLDI] = {.handler = probes_simulate_nop},
 	[PROBES_T32_LDR_LIT] = {.handler = t32_simulate_ldr_literal},
 	[PROBES_T32_LDRSTR] = {.handler = t32_emulate_ldrstr},
 	[PROBES_T32_SIGN_EXTEND] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
 	[PROBES_T32_MEDIA] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
 	[PROBES_T32_REVERSE] = {.handler = t32_emulate_rd8rn16_noflags},
 	[PROBES_T32_MUL_ADD] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
 	[PROBES_T32_MUL_ADD2] = {.handler = t32_emulate_rd8rn16rm0ra12_noflags},
 	[PROBES_T32_MUL_ADD_LONG] = {
 		.handler = t32_emulate_rdlo12rdhi8rn16rm0_noflags},
 };
	/*
	* arch/arm/kernel/kprobes-thumb.c
	*
	* Copyright (C) 2011 Jon Medhurst <tixy@yxit.co.uk>.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*/

	#include <linux/types.h>
	#include <linux/kernel.h>
	#include <linux/ptrace.h>
	#include <linux/kprobes.h>

	#include "kprobes.h"
	#include "probes-thumb.h"

	/* These emulation encodings are functionally equivalent... */
	#define t32_emulate_rd8rn16rm0ra12_noflags \
	t32_emulate_rdlo12rdhi8rn16rm0_noflags

	/* t32 thumb actions */

	static void __kprobes
	t32_simulate_table_branch(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	unsigned long pc = regs->ARM_pc;
	int rn = (insn >> 16) & 0xf;
	int rm = insn & 0xf;

	unsigned long rnv = (rn == 15) ? pc : regs->uregs[rn];
	unsigned long rmv = regs->uregs[rm];
	unsigned int halfwords;

	if (insn & 0x10) /* TBH */
	halfwords = ((u16 *)rnv)[rmv];
	else /* TBB */
	halfwords = ((u8 *)rnv)[rmv];

	regs->ARM_pc = pc + 2 * halfwords;
	}

	static void __kprobes
	t32_simulate_mrs(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	int rd = (insn >> 8) & 0xf;
	unsigned long mask = 0xf8ff03df; /* Mask out execution state */
	regs->uregs[rd] = regs->ARM_cpsr & mask;
	}

	static void __kprobes
	t32_simulate_cond_branch(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	unsigned long pc = regs->ARM_pc;

	long offset = insn & 0x7ff; /* imm11 */
	offset += (insn & 0x003f0000) >> 5; /* imm6 */
	offset += (insn & 0x00002000) << 4; /* J1 */
	offset += (insn & 0x00000800) << 7; /* J2 */
	offset -= (insn & 0x04000000) >> 7; /* Apply sign bit */

	regs->ARM_pc = pc + (offset * 2);
	}

	static enum probes_insn __kprobes
	t32_decode_cond_branch(probes_opcode_t insn, struct arch_probes_insn *asi,
	const struct decode_header *d)
	{
	int cc = (insn >> 22) & 0xf;
	asi->insn_check_cc = probes_condition_checks[cc];
	asi->insn_handler = t32_simulate_cond_branch;
	return INSN_GOOD_NO_SLOT;
	}

	static void __kprobes
	t32_simulate_branch(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	unsigned long pc = regs->ARM_pc;

	long offset = insn & 0x7ff; /* imm11 */
	offset += (insn & 0x03ff0000) >> 5; /* imm10 */
	offset += (insn & 0x00002000) << 9; /* J1 */
	offset += (insn & 0x00000800) << 10; /* J2 */
	if (insn & 0x04000000)
	offset -= 0x00800000; /* Apply sign bit */
	else
	offset ^= 0x00600000; /* Invert J1 and J2 */

	if (insn & (1 << 14)) {
	/* BL or BLX */
	regs->ARM_lr = regs->ARM_pc \| 1;
	if (!(insn & (1 << 12))) {
	/* BLX so switch to ARM mode */
	regs->ARM_cpsr &= ~PSR_T_BIT;
	pc &= ~3;
	}
	}

	regs->ARM_pc = pc + (offset * 2);
	}

	static void __kprobes
	t32_simulate_ldr_literal(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	unsigned long addr = regs->ARM_pc & ~3;
	int rt = (insn >> 12) & 0xf;
	unsigned long rtv;

	long offset = insn & 0xfff;
	if (insn & 0x00800000)
	addr += offset;
	else
	addr -= offset;

	if (insn & 0x00400000) {
	/* LDR */
	rtv = (unsigned long )addr;
	if (rt == 15) {
	bx_write_pc(rtv, regs);
	return;
	}
	} else if (insn & 0x00200000) {
	/* LDRH */
	if (insn & 0x01000000)
	rtv = (s16 )addr;
	else
	rtv = (u16 )addr;
	} else {
	/* LDRB */
	if (insn & 0x01000000)
	rtv = (s8 )addr;
	else
	rtv = (u8 )addr;
	}

	regs->uregs[rt] = rtv;
	}

	static enum probes_insn __kprobes
	t32_decode_ldmstm(probes_opcode_t insn, struct arch_probes_insn *asi,
	const struct decode_header *d)
	{
	enum probes_insn ret = kprobe_decode_ldmstm(insn, asi, d);

	/* Fixup modified instruction to have halfwords in correct order...*/
	insn = __mem_to_opcode_arm(asi->insn[0]);
	((u16 *)asi->insn)[0] = __opcode_to_mem_thumb16(insn >> 16);
	((u16 *)asi->insn)[1] = __opcode_to_mem_thumb16(insn & 0xffff);

	return ret;
	}

	static void __kprobes
	t32_emulate_ldrdstrd(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	unsigned long pc = regs->ARM_pc & ~3;
	int rt1 = (insn >> 12) & 0xf;
	int rt2 = (insn >> 8) & 0xf;
	int rn = (insn >> 16) & 0xf;

	register unsigned long rt1v asm("r0") = regs->uregs[rt1];
	register unsigned long rt2v asm("r1") = regs->uregs[rt2];
	register unsigned long rnv asm("r2") = (rn == 15) ? pc
	: regs->uregs[rn];

	__asm__ __volatile__ (
	"blx %[fn]"
	: "=r" (rt1v), "=r" (rt2v), "=r" (rnv)
	: "0" (rt1v), "1" (rt2v), "2" (rnv), [fn] "r" (asi->insn_fn)
	: "lr", "memory", "cc"
	);

	if (rn != 15)
	regs->uregs[rn] = rnv; /* Writeback base register */
	regs->uregs[rt1] = rt1v;
	regs->uregs[rt2] = rt2v;
	}

	static void __kprobes
	t32_emulate_ldrstr(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	int rt = (insn >> 12) & 0xf;
	int rn = (insn >> 16) & 0xf;
	int rm = insn & 0xf;

	register unsigned long rtv asm("r0") = regs->uregs[rt];
	register unsigned long rnv asm("r2") = regs->uregs[rn];
	register unsigned long rmv asm("r3") = regs->uregs[rm];

	__asm__ __volatile__ (
	"blx %[fn]"
	: "=r" (rtv), "=r" (rnv)
	: "0" (rtv), "1" (rnv), "r" (rmv), [fn] "r" (asi->insn_fn)
	: "lr", "memory", "cc"
	);

	regs->uregs[rn] = rnv; /* Writeback base register */
	if (rt == 15) /* Can't be true for a STR as they aren't allowed */
	bx_write_pc(rtv, regs);
	else
	regs->uregs[rt] = rtv;
	}

	static void __kprobes
	t32_emulate_rd8rn16rm0_rwflags(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	int rd = (insn >> 8) & 0xf;
	int rn = (insn >> 16) & 0xf;
	int rm = insn & 0xf;

	register unsigned long rdv asm("r1") = regs->uregs[rd];
	register unsigned long rnv asm("r2") = regs->uregs[rn];
	register unsigned long rmv asm("r3") = regs->uregs[rm];
	unsigned long cpsr = regs->ARM_cpsr;

	__asm__ __volatile__ (
	"msr cpsr_fs, %[cpsr] \n\t"
	"blx %[fn] \n\t"
	"mrs %[cpsr], cpsr \n\t"
	: "=r" (rdv), [cpsr] "=r" (cpsr)
	: "0" (rdv), "r" (rnv), "r" (rmv),
	"1" (cpsr), [fn] "r" (asi->insn_fn)
	: "lr", "memory", "cc"
	);

	regs->uregs[rd] = rdv;
	regs->ARM_cpsr = (regs->ARM_cpsr & ~APSR_MASK) \| (cpsr & APSR_MASK);
	}

	static void __kprobes
	t32_emulate_rd8pc16_noflags(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	unsigned long pc = regs->ARM_pc;
	int rd = (insn >> 8) & 0xf;

	register unsigned long rdv asm("r1") = regs->uregs[rd];
	register unsigned long rnv asm("r2") = pc & ~3;

	__asm__ __volatile__ (
	"blx %[fn]"
	: "=r" (rdv)
	: "0" (rdv), "r" (rnv), [fn] "r" (asi->insn_fn)
	: "lr", "memory", "cc"
	);

	regs->uregs[rd] = rdv;
	}

	static void __kprobes
	t32_emulate_rd8rn16_noflags(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	int rd = (insn >> 8) & 0xf;
	int rn = (insn >> 16) & 0xf;

	register unsigned long rdv asm("r1") = regs->uregs[rd];
	register unsigned long rnv asm("r2") = regs->uregs[rn];

	__asm__ __volatile__ (
	"blx %[fn]"
	: "=r" (rdv)
	: "0" (rdv), "r" (rnv), [fn] "r" (asi->insn_fn)
	: "lr", "memory", "cc"
	);

	regs->uregs[rd] = rdv;
	}

	static void __kprobes
	t32_emulate_rdlo12rdhi8rn16rm0_noflags(probes_opcode_t insn,
	struct arch_probes_insn *asi,
	struct pt_regs *regs)
	{
	int rdlo = (insn >> 12) & 0xf;
	int rdhi = (insn >> 8) & 0xf;
	int rn = (insn >> 16) & 0xf;
	int rm = insn & 0xf;

	register unsigned long rdlov asm("r0") = regs->uregs[rdlo];
	register unsigned long rdhiv asm("r1") = regs->uregs[rdhi];
	register unsigned long rnv asm("r2") = regs->uregs[rn];
	register unsigned long rmv asm("r3") = regs->uregs[rm];

	__asm__ __volatile__ (
	"blx %[fn]"
	: "=r" (rdlov), "=r" (rdhiv)
	: "0" (rdlov), "1" (rdhiv), "r" (rnv), "r" (rmv),
	[fn] "r" (asi->insn_fn)
	: "lr", "memory", "cc"
	);

	regs->uregs[rdlo] = rdlov;
	regs->uregs[rdhi] = rdhiv;
	}
	/* t16 thumb actions */

	static void __kprobes
	t16_simulate_bxblx(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	unsigned long pc = regs->ARM_pc + 2;
	int rm = (insn >> 3) & 0xf;
	unsigned long rmv = (rm == 15) ? pc : regs->uregs[rm];

	if (insn & (1 << 7)) /* BLX ? */
	regs->ARM_lr = regs->ARM_pc \| 1;

	bx_write_pc(rmv, regs);
	}

	static void __kprobes
	t16_simulate_ldr_literal(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	unsigned long base = (unsigned long )((regs->ARM_pc + 2) & ~3);
	long index = insn & 0xff;
	int rt = (insn >> 8) & 0x7;
	regs->uregs[rt] = base[index];
	}

	static void __kprobes
	t16_simulate_ldrstr_sp_relative(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	unsigned long* base = (unsigned long *)regs->ARM_sp;
	long index = insn & 0xff;
	int rt = (insn >> 8) & 0x7;
	if (insn & 0x800) /* LDR */
	regs->uregs[rt] = base[index];
	else /* STR */
	base[index] = regs->uregs[rt];
	}

	static void __kprobes
	t16_simulate_reladr(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	unsigned long base = (insn & 0x800) ? regs->ARM_sp
	: ((regs->ARM_pc + 2) & ~3);
	long offset = insn & 0xff;
	int rt = (insn >> 8) & 0x7;
	regs->uregs[rt] = base + offset * 4;
	}

	static void __kprobes
	t16_simulate_add_sp_imm(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	long imm = insn & 0x7f;
	if (insn & 0x80) /* SUB */
	regs->ARM_sp -= imm * 4;
	else /* ADD */
	regs->ARM_sp += imm * 4;
	}

	static void __kprobes
	t16_simulate_cbz(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	int rn = insn & 0x7;
	probes_opcode_t nonzero = regs->uregs[rn] ? insn : ~insn;
	if (nonzero & 0x800) {
	long i = insn & 0x200;
	long imm5 = insn & 0xf8;
	unsigned long pc = regs->ARM_pc + 2;
	regs->ARM_pc = pc + (i >> 3) + (imm5 >> 2);
	}
	}

	static void __kprobes
	t16_simulate_it(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	/*
	* The 8 IT state bits are split into two parts in CPSR:
	* ITSTATE<1:0> are in CPSR<26:25>
	* ITSTATE<7:2> are in CPSR<15:10>
	* The new IT state is in the lower byte of insn.
	*/
	unsigned long cpsr = regs->ARM_cpsr;
	cpsr &= ~PSR_IT_MASK;
	cpsr \|= (insn & 0xfc) << 8;
	cpsr \|= (insn & 0x03) << 25;
	regs->ARM_cpsr = cpsr;
	}

	static void __kprobes
	t16_singlestep_it(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	regs->ARM_pc += 2;
	t16_simulate_it(insn, asi, regs);
	}

	static enum probes_insn __kprobes
	t16_decode_it(probes_opcode_t insn, struct arch_probes_insn *asi,
	const struct decode_header *d)
	{
	asi->insn_singlestep = t16_singlestep_it;
	return INSN_GOOD_NO_SLOT;
	}

	static void __kprobes
	t16_simulate_cond_branch(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	unsigned long pc = regs->ARM_pc + 2;
	long offset = insn & 0x7f;
	offset -= insn & 0x80; /* Apply sign bit */
	regs->ARM_pc = pc + (offset * 2);
	}

	static enum probes_insn __kprobes
	t16_decode_cond_branch(probes_opcode_t insn, struct arch_probes_insn *asi,
	const struct decode_header *d)
	{
	int cc = (insn >> 8) & 0xf;
	asi->insn_check_cc = probes_condition_checks[cc];
	asi->insn_handler = t16_simulate_cond_branch;
	return INSN_GOOD_NO_SLOT;
	}

	static void __kprobes
	t16_simulate_branch(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	unsigned long pc = regs->ARM_pc + 2;
	long offset = insn & 0x3ff;
	offset -= insn & 0x400; /* Apply sign bit */
	regs->ARM_pc = pc + (offset * 2);
	}

	static unsigned long __kprobes
	t16_emulate_loregs(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	unsigned long oldcpsr = regs->ARM_cpsr;
	unsigned long newcpsr;

	__asm__ __volatile__ (
	"msr cpsr_fs, %[oldcpsr] \n\t"
	"ldmia %[regs], {r0-r7} \n\t"
	"blx %[fn] \n\t"
	"stmia %[regs], {r0-r7} \n\t"
	"mrs %[newcpsr], cpsr \n\t"
	: [newcpsr] "=r" (newcpsr)
	: [oldcpsr] "r" (oldcpsr), [regs] "r" (regs),
	[fn] "r" (asi->insn_fn)
	: "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
	"lr", "memory", "cc"
	);

	return (oldcpsr & ~APSR_MASK) \| (newcpsr & APSR_MASK);
	}

	static void __kprobes
	t16_emulate_loregs_rwflags(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	regs->ARM_cpsr = t16_emulate_loregs(insn, asi, regs);
	}

	static void __kprobes
	t16_emulate_loregs_noitrwflags(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	unsigned long cpsr = t16_emulate_loregs(insn, asi, regs);
	if (!in_it_block(cpsr))
	regs->ARM_cpsr = cpsr;
	}

	static void __kprobes
	t16_emulate_hiregs(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	unsigned long pc = regs->ARM_pc + 2;
	int rdn = (insn & 0x7) \| ((insn & 0x80) >> 4);
	int rm = (insn >> 3) & 0xf;

	register unsigned long rdnv asm("r1");
	register unsigned long rmv asm("r0");
	unsigned long cpsr = regs->ARM_cpsr;

	rdnv = (rdn == 15) ? pc : regs->uregs[rdn];
	rmv = (rm == 15) ? pc : regs->uregs[rm];

	__asm__ __volatile__ (
	"msr cpsr_fs, %[cpsr] \n\t"
	"blx %[fn] \n\t"
	"mrs %[cpsr], cpsr \n\t"
	: "=r" (rdnv), [cpsr] "=r" (cpsr)
	: "0" (rdnv), "r" (rmv), "1" (cpsr), [fn] "r" (asi->insn_fn)
	: "lr", "memory", "cc"
	);

	if (rdn == 15)
	rdnv &= ~1;

	regs->uregs[rdn] = rdnv;
	regs->ARM_cpsr = (regs->ARM_cpsr & ~APSR_MASK) \| (cpsr & APSR_MASK);
	}

	static enum probes_insn __kprobes
	t16_decode_hiregs(probes_opcode_t insn, struct arch_probes_insn *asi,
	const struct decode_header *d)
	{
	insn &= ~0x00ff;
	insn \|= 0x001; /* Set Rdn = R1 and Rm = R0 */
	((u16 *)asi->insn)[0] = __opcode_to_mem_thumb16(insn);
	asi->insn_handler = t16_emulate_hiregs;
	return INSN_GOOD;
	}

	static void __kprobes
	t16_emulate_push(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	__asm__ __volatile__ (
	"ldr r9, [%[regs], #13*4] \n\t"
	"ldr r8, [%[regs], #14*4] \n\t"
	"ldmia %[regs], {r0-r7} \n\t"
	"blx %[fn] \n\t"
	"str r9, [%[regs], #13*4] \n\t"
	:
	: [regs] "r" (regs), [fn] "r" (asi->insn_fn)
	: "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", "r8", "r9",
	"lr", "memory", "cc"
	);
	}

	static enum probes_insn __kprobes
	t16_decode_push(probes_opcode_t insn, struct arch_probes_insn *asi,
	const struct decode_header *d)
	{
	/*
	* To simulate a PUSH we use a Thumb-2 "STMDB R9!, {registers}"
	* and call it with R9=SP and LR in the register list represented
	* by R8.
	*/
	/* 1st half STMDB R9!,{} */
	((u16 *)asi->insn)[0] = __opcode_to_mem_thumb16(0xe929);
	/* 2nd half (register list) */
	((u16 *)asi->insn)[1] = __opcode_to_mem_thumb16(insn & 0x1ff);
	asi->insn_handler = t16_emulate_push;
	return INSN_GOOD;
	}

	static void __kprobes
	t16_emulate_pop_nopc(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	__asm__ __volatile__ (
	"ldr r9, [%[regs], #13*4] \n\t"
	"ldmia %[regs], {r0-r7} \n\t"
	"blx %[fn] \n\t"
	"stmia %[regs], {r0-r7} \n\t"
	"str r9, [%[regs], #13*4] \n\t"
	:
	: [regs] "r" (regs), [fn] "r" (asi->insn_fn)
	: "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", "r9",
	"lr", "memory", "cc"
	);
	}

	static void __kprobes
	t16_emulate_pop_pc(probes_opcode_t insn,
	struct arch_probes_insn asi, struct pt_regs regs)
	{
	register unsigned long pc asm("r8");

	__asm__ __volatile__ (
	"ldr r9, [%[regs], #13*4] \n\t"
	"ldmia %[regs], {r0-r7} \n\t"
	"blx %[fn] \n\t"
	"stmia %[regs], {r0-r7} \n\t"
	"str r9, [%[regs], #13*4] \n\t"
	: "=r" (pc)
	: [regs] "r" (regs), [fn] "r" (asi->insn_fn)
	: "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", "r9",
	"lr", "memory", "cc"
	);

	bx_write_pc(pc, regs);
	}

	static enum probes_insn __kprobes
	t16_decode_pop(probes_opcode_t insn, struct arch_probes_insn *asi,
	const struct decode_header *d)
	{
	/*
	* To simulate a POP we use a Thumb-2 "LDMDB R9!, {registers}"
	* and call it with R9=SP and PC in the register list represented
	* by R8.
	*/
	/* 1st half LDMIA R9!,{} */
	((u16 *)asi->insn)[0] = __opcode_to_mem_thumb16(0xe8b9);
	/* 2nd half (register list) */
	((u16 *)asi->insn)[1] = __opcode_to_mem_thumb16(insn & 0x1ff);
	asi->insn_handler = insn & 0x100 ? t16_emulate_pop_pc
	: t16_emulate_pop_nopc;
	return INSN_GOOD;
	}

	const union decode_action kprobes_t16_actions[NUM_PROBES_T16_ACTIONS] = {
	[PROBES_T16_ADD_SP] = {.handler = t16_simulate_add_sp_imm},
	[PROBES_T16_CBZ] = {.handler = t16_simulate_cbz},
	[PROBES_T16_SIGN_EXTEND] = {.handler = t16_emulate_loregs_rwflags},
	[PROBES_T16_PUSH] = {.decoder = t16_decode_push},
	[PROBES_T16_POP] = {.decoder = t16_decode_pop},
	[PROBES_T16_SEV] = {.handler = probes_emulate_none},
	[PROBES_T16_WFE] = {.handler = probes_simulate_nop},
	[PROBES_T16_IT] = {.decoder = t16_decode_it},
	[PROBES_T16_CMP] = {.handler = t16_emulate_loregs_rwflags},
	[PROBES_T16_ADDSUB] = {.handler = t16_emulate_loregs_noitrwflags},
	[PROBES_T16_LOGICAL] = {.handler = t16_emulate_loregs_noitrwflags},
	[PROBES_T16_LDR_LIT] = {.handler = t16_simulate_ldr_literal},
	[PROBES_T16_BLX] = {.handler = t16_simulate_bxblx},
	[PROBES_T16_HIREGOPS] = {.decoder = t16_decode_hiregs},
	[PROBES_T16_LDRHSTRH] = {.handler = t16_emulate_loregs_rwflags},
	[PROBES_T16_LDRSTR] = {.handler = t16_simulate_ldrstr_sp_relative},
	[PROBES_T16_ADR] = {.handler = t16_simulate_reladr},
	[PROBES_T16_LDMSTM] = {.handler = t16_emulate_loregs_rwflags},
	[PROBES_T16_BRANCH_COND] = {.decoder = t16_decode_cond_branch},
	[PROBES_T16_BRANCH] = {.handler = t16_simulate_branch},
	};

	const union decode_action kprobes_t32_actions[NUM_PROBES_T32_ACTIONS] = {
	[PROBES_T32_LDMSTM] = {.decoder = t32_decode_ldmstm},
	[PROBES_T32_LDRDSTRD] = {.handler = t32_emulate_ldrdstrd},
	[PROBES_T32_TABLE_BRANCH] = {.handler = t32_simulate_table_branch},
	[PROBES_T32_TST] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
	[PROBES_T32_MOV] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
	[PROBES_T32_ADDSUB] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
	[PROBES_T32_LOGICAL] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
	[PROBES_T32_CMP] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
	[PROBES_T32_ADDWSUBW_PC] = {.handler = t32_emulate_rd8pc16_noflags,},
	[PROBES_T32_ADDWSUBW] = {.handler = t32_emulate_rd8rn16_noflags},
	[PROBES_T32_MOVW] = {.handler = t32_emulate_rd8rn16_noflags},
	[PROBES_T32_SAT] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
	[PROBES_T32_BITFIELD] = {.handler = t32_emulate_rd8rn16_noflags},
	[PROBES_T32_SEV] = {.handler = probes_emulate_none},
	[PROBES_T32_WFE] = {.handler = probes_simulate_nop},
	[PROBES_T32_MRS] = {.handler = t32_simulate_mrs},
	[PROBES_T32_BRANCH_COND] = {.decoder = t32_decode_cond_branch},
	[PROBES_T32_BRANCH] = {.handler = t32_simulate_branch},
	[PROBES_T32_PLDI] = {.handler = probes_simulate_nop},
	[PROBES_T32_LDR_LIT] = {.handler = t32_simulate_ldr_literal},
	[PROBES_T32_LDRSTR] = {.handler = t32_emulate_ldrstr},
	[PROBES_T32_SIGN_EXTEND] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
	[PROBES_T32_MEDIA] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
	[PROBES_T32_REVERSE] = {.handler = t32_emulate_rd8rn16_noflags},
	[PROBES_T32_MUL_ADD] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
	[PROBES_T32_MUL_ADD2] = {.handler = t32_emulate_rd8rn16rm0ra12_noflags},
	[PROBES_T32_MUL_ADD_LONG] = {
	.handler = t32_emulate_rdlo12rdhi8rn16rm0_noflags},
	};