2 * arch/arm/kernel/kprobes-thumb.c
4 * Copyright (C) 2011 Jon Medhurst <tixy@yxit.co.uk>.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
11 #include <linux/kernel.h>
12 #include <linux/kprobes.h>
18 * True if current instruction is in an IT block.
20 #define in_it_block(cpsr) ((cpsr & 0x06000c00) != 0x00000000)
23 * Return the condition code to check for the currently executing instruction.
24 * This is in ITSTATE<7:4> which is in CPSR<15:12> but is only valid if
25 * in_it_block returns true.
27 #define current_cond(cpsr) ((cpsr >> 12) & 0xf)
29 static const union decode_item t16_table_1011[] = {
30 /* Miscellaneous 16-bit instructions */
37 /* YIELD 1011 1111 0001 0000 */
38 DECODE_OR (0xffff, 0xbf10),
39 /* SEV 1011 1111 0100 0000 */
40 DECODE_EMULATE (0xffff, 0xbf40, kprobe_emulate_none),
41 /* NOP 1011 1111 0000 0000 */
42 /* WFE 1011 1111 0010 0000 */
43 /* WFI 1011 1111 0011 0000 */
44 DECODE_SIMULATE (0xffcf, 0xbf00, kprobe_simulate_nop),
45 /* Unassigned hints 1011 1111 xxxx 0000 */
46 DECODE_REJECT (0xff0f, 0xbf00),
51 const union decode_item kprobe_decode_thumb16_table[] = {
54 * Miscellaneous 16-bit instructions
57 DECODE_TABLE (0xf000, 0xb000, t16_table_1011),
62 static unsigned long __kprobes thumb_check_cc(unsigned long cpsr)
64 if (unlikely(in_it_block(cpsr)))
65 return kprobe_condition_checks[current_cond(cpsr)](cpsr);
69 static void __kprobes thumb16_singlestep(struct kprobe *p, struct pt_regs *regs)
72 p->ainsn.insn_handler(p, regs);
73 regs->ARM_cpsr = it_advance(regs->ARM_cpsr);
76 static void __kprobes thumb32_singlestep(struct kprobe *p, struct pt_regs *regs)
79 p->ainsn.insn_handler(p, regs);
80 regs->ARM_cpsr = it_advance(regs->ARM_cpsr);
83 enum kprobe_insn __kprobes
84 thumb16_kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi)
86 asi->insn_singlestep = thumb16_singlestep;
87 asi->insn_check_cc = thumb_check_cc;
88 return kprobe_decode_insn(insn, asi, kprobe_decode_thumb16_table, true);
91 enum kprobe_insn __kprobes
92 thumb32_kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi)
94 asi->insn_singlestep = thumb32_singlestep;
95 asi->insn_check_cc = thumb_check_cc;