2 * arch/arm/kernel/kprobes-common.c
4 * Copyright (C) 2011 Jon Medhurst <tixy@yxit.co.uk>.
6 * Some contents moved here from arch/arm/include/asm/kprobes-arm.c which is
7 * Copyright (C) 2006, 2007 Motorola Inc.
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
14 #include <linux/kernel.h>
15 #include <linux/kprobes.h>
20 static void __kprobes simulate_ldm1stm1(probes_opcode_t insn,
21 struct arch_probes_insn *asi,
24 int rn = (insn >> 16) & 0xf;
25 int lbit = insn & (1 << 20);
26 int wbit = insn & (1 << 21);
27 int ubit = insn & (1 << 23);
28 int pbit = insn & (1 << 24);
29 long *addr = (long *)regs->uregs[rn];
34 reg_bit_vector = insn & 0xffff;
35 while (reg_bit_vector) {
36 reg_bit_vector &= (reg_bit_vector - 1);
42 addr += (!pbit == !ubit);
44 reg_bit_vector = insn & 0xffff;
45 while (reg_bit_vector) {
46 int reg = __ffs(reg_bit_vector);
47 reg_bit_vector &= (reg_bit_vector - 1);
49 regs->uregs[reg] = *addr++;
51 *addr++ = regs->uregs[reg];
57 addr -= (!pbit == !ubit);
58 regs->uregs[rn] = (long)addr;
62 static void __kprobes simulate_stm1_pc(probes_opcode_t insn,
63 struct arch_probes_insn *asi,
66 unsigned long addr = regs->ARM_pc - 4;
68 regs->ARM_pc = (long)addr + str_pc_offset;
69 simulate_ldm1stm1(insn, asi, regs);
70 regs->ARM_pc = (long)addr + 4;
73 static void __kprobes simulate_ldm1_pc(probes_opcode_t insn,
74 struct arch_probes_insn *asi,
77 simulate_ldm1stm1(insn, asi, regs);
78 load_write_pc(regs->ARM_pc, regs);
82 emulate_generic_r0_12_noflags(probes_opcode_t insn,
83 struct arch_probes_insn *asi, struct pt_regs *regs)
85 register void *rregs asm("r1") = regs;
86 register void *rfn asm("lr") = asi->insn_fn;
88 __asm__ __volatile__ (
89 "stmdb sp!, {%[regs], r11} \n\t"
90 "ldmia %[regs], {r0-r12} \n\t"
91 #if __LINUX_ARM_ARCH__ >= 6
94 "str %[fn], [sp, #-4]! \n\t"
96 "ldr pc, [sp], #4 \n\t"
99 "ldr lr, [sp], #4 \n\t" /* lr = regs */
100 "stmia lr, {r0-r12} \n\t"
101 "ldr r11, [sp], #4 \n\t"
102 : [regs] "=r" (rregs), [fn] "=r" (rfn)
103 : "0" (rregs), "1" (rfn)
104 : "r0", "r2", "r3", "r4", "r5", "r6", "r7",
105 "r8", "r9", "r10", "r12", "memory", "cc"
109 static void __kprobes
110 emulate_generic_r2_14_noflags(probes_opcode_t insn,
111 struct arch_probes_insn *asi, struct pt_regs *regs)
113 emulate_generic_r0_12_noflags(insn, asi,
114 (struct pt_regs *)(regs->uregs+2));
117 static void __kprobes
118 emulate_ldm_r3_15(probes_opcode_t insn,
119 struct arch_probes_insn *asi, struct pt_regs *regs)
121 emulate_generic_r0_12_noflags(insn, asi,
122 (struct pt_regs *)(regs->uregs+3));
123 load_write_pc(regs->ARM_pc, regs);
126 enum probes_insn __kprobes
127 kprobe_decode_ldmstm(probes_opcode_t insn, struct arch_probes_insn *asi,
128 const struct decode_header *h)
130 probes_insn_handler_t *handler = 0;
131 unsigned reglist = insn & 0xffff;
132 int is_ldm = insn & 0x100000;
133 int rn = (insn >> 16) & 0xf;
135 if (rn <= 12 && (reglist & 0xe000) == 0) {
136 /* Instruction only uses registers in the range R0..R12 */
137 handler = emulate_generic_r0_12_noflags;
139 } else if (rn >= 2 && (reglist & 0x8003) == 0) {
140 /* Instruction only uses registers in the range R2..R14 */
143 handler = emulate_generic_r2_14_noflags;
145 } else if (rn >= 3 && (reglist & 0x0007) == 0) {
146 /* Instruction only uses registers in the range R3..R15 */
147 if (is_ldm && (reglist & 0x8000)) {
150 handler = emulate_ldm_r3_15;
155 /* We can emulate the instruction in (possibly) modified form */
156 asi->insn[0] = (insn & 0xfff00000) | (rn << 16) | reglist;
157 asi->insn_handler = handler;
161 /* Fallback to slower simulation... */
162 if (reglist & 0x8000)
163 handler = is_ldm ? simulate_ldm1_pc : simulate_stm1_pc;
165 handler = simulate_ldm1stm1;
166 asi->insn_handler = handler;
167 return INSN_GOOD_NO_SLOT;