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>
16 #include <asm/opcodes.h>
21 static void __kprobes simulate_ldm1stm1(probes_opcode_t insn,
22 struct arch_probes_insn *asi,
25 int rn = (insn >> 16) & 0xf;
26 int lbit = insn & (1 << 20);
27 int wbit = insn & (1 << 21);
28 int ubit = insn & (1 << 23);
29 int pbit = insn & (1 << 24);
30 long *addr = (long *)regs->uregs[rn];
35 reg_bit_vector = insn & 0xffff;
36 while (reg_bit_vector) {
37 reg_bit_vector &= (reg_bit_vector - 1);
43 addr += (!pbit == !ubit);
45 reg_bit_vector = insn & 0xffff;
46 while (reg_bit_vector) {
47 int reg = __ffs(reg_bit_vector);
48 reg_bit_vector &= (reg_bit_vector - 1);
50 regs->uregs[reg] = *addr++;
52 *addr++ = regs->uregs[reg];
58 addr -= (!pbit == !ubit);
59 regs->uregs[rn] = (long)addr;
63 static void __kprobes simulate_stm1_pc(probes_opcode_t insn,
64 struct arch_probes_insn *asi,
67 unsigned long addr = regs->ARM_pc - 4;
69 regs->ARM_pc = (long)addr + str_pc_offset;
70 simulate_ldm1stm1(insn, asi, regs);
71 regs->ARM_pc = (long)addr + 4;
74 static void __kprobes simulate_ldm1_pc(probes_opcode_t insn,
75 struct arch_probes_insn *asi,
78 simulate_ldm1stm1(insn, asi, regs);
79 load_write_pc(regs->ARM_pc, regs);
83 emulate_generic_r0_12_noflags(probes_opcode_t insn,
84 struct arch_probes_insn *asi, struct pt_regs *regs)
86 register void *rregs asm("r1") = regs;
87 register void *rfn asm("lr") = asi->insn_fn;
89 __asm__ __volatile__ (
90 "stmdb sp!, {%[regs], r11} \n\t"
91 "ldmia %[regs], {r0-r12} \n\t"
92 #if __LINUX_ARM_ARCH__ >= 6
95 "str %[fn], [sp, #-4]! \n\t"
97 "ldr pc, [sp], #4 \n\t"
100 "ldr lr, [sp], #4 \n\t" /* lr = regs */
101 "stmia lr, {r0-r12} \n\t"
102 "ldr r11, [sp], #4 \n\t"
103 : [regs] "=r" (rregs), [fn] "=r" (rfn)
104 : "0" (rregs), "1" (rfn)
105 : "r0", "r2", "r3", "r4", "r5", "r6", "r7",
106 "r8", "r9", "r10", "r12", "memory", "cc"
110 static void __kprobes
111 emulate_generic_r2_14_noflags(probes_opcode_t insn,
112 struct arch_probes_insn *asi, struct pt_regs *regs)
114 emulate_generic_r0_12_noflags(insn, asi,
115 (struct pt_regs *)(regs->uregs+2));
118 static void __kprobes
119 emulate_ldm_r3_15(probes_opcode_t insn,
120 struct arch_probes_insn *asi, struct pt_regs *regs)
122 emulate_generic_r0_12_noflags(insn, asi,
123 (struct pt_regs *)(regs->uregs+3));
124 load_write_pc(regs->ARM_pc, regs);
127 enum probes_insn __kprobes
128 kprobe_decode_ldmstm(probes_opcode_t insn, struct arch_probes_insn *asi,
129 const struct decode_header *h)
131 probes_insn_handler_t *handler = 0;
132 unsigned reglist = insn & 0xffff;
133 int is_ldm = insn & 0x100000;
134 int rn = (insn >> 16) & 0xf;
136 if (rn <= 12 && (reglist & 0xe000) == 0) {
137 /* Instruction only uses registers in the range R0..R12 */
138 handler = emulate_generic_r0_12_noflags;
140 } else if (rn >= 2 && (reglist & 0x8003) == 0) {
141 /* Instruction only uses registers in the range R2..R14 */
144 handler = emulate_generic_r2_14_noflags;
146 } else if (rn >= 3 && (reglist & 0x0007) == 0) {
147 /* Instruction only uses registers in the range R3..R15 */
148 if (is_ldm && (reglist & 0x8000)) {
151 handler = emulate_ldm_r3_15;
156 /* We can emulate the instruction in (possibly) modified form */
157 asi->insn[0] = __opcode_to_mem_arm((insn & 0xfff00000) |
158 (rn << 16) | reglist);
159 asi->insn_handler = handler;
163 /* Fallback to slower simulation... */
164 if (reglist & 0x8000)
165 handler = is_ldm ? simulate_ldm1_pc : simulate_stm1_pc;
167 handler = simulate_ldm1stm1;
168 asi->insn_handler = handler;
169 return INSN_GOOD_NO_SLOT;