2 * Copyright (C) 2012 Rabin Vincent <rabin at rab.in>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
9 #include <linux/kernel.h>
10 #include <linux/stddef.h>
11 #include <linux/errno.h>
12 #include <linux/highmem.h>
13 #include <linux/sched.h>
14 #include <linux/uprobes.h>
15 #include <linux/notifier.h>
17 #include <asm/opcodes.h>
18 #include <asm/traps.h>
21 #include "probes-arm.h"
24 #define UPROBE_TRAP_NR UINT_MAX
26 bool is_swbp_insn(uprobe_opcode_t *insn)
28 return (__mem_to_opcode_arm(*insn) & 0x0fffffff) ==
29 (UPROBE_SWBP_ARM_INSN & 0x0fffffff);
32 int set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm,
35 return uprobe_write_opcode(mm, vaddr,
36 __opcode_to_mem_arm(auprobe->bpinsn));
39 bool arch_uprobe_ignore(struct arch_uprobe *auprobe, struct pt_regs *regs)
41 if (!auprobe->asi.insn_check_cc(regs->ARM_cpsr)) {
49 bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
51 probes_opcode_t opcode;
53 if (!auprobe->simulate)
56 opcode = __mem_to_opcode_arm(*(unsigned int *) auprobe->insn);
58 auprobe->asi.insn_singlestep(opcode, &auprobe->asi, regs);
64 arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr,
67 unsigned long orig_ret_vaddr;
69 orig_ret_vaddr = regs->ARM_lr;
70 /* Replace the return addr with trampoline addr */
71 regs->ARM_lr = trampoline_vaddr;
72 return orig_ret_vaddr;
75 int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
82 /* Thumb not yet support */
86 insn = __mem_to_opcode_arm(*(unsigned int *)auprobe->insn);
87 auprobe->ixol[0] = __opcode_to_mem_arm(insn);
88 auprobe->ixol[1] = __opcode_to_mem_arm(UPROBE_SS_ARM_INSN);
90 ret = arm_probes_decode_insn(insn, &auprobe->asi, false,
91 uprobes_probes_actions);
96 case INSN_GOOD_NO_SLOT:
97 auprobe->simulate = true;
105 bpinsn = UPROBE_SWBP_ARM_INSN & 0x0fffffff;
106 if (insn >= 0xe0000000)
107 bpinsn |= 0xe0000000; /* Unconditional instruction */
109 bpinsn |= insn & 0xf0000000; /* Copy condition from insn */
111 auprobe->bpinsn = bpinsn;
116 int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
118 struct uprobe_task *utask = current->utask;
120 if (auprobe->prehandler)
121 auprobe->prehandler(auprobe, &utask->autask, regs);
123 utask->autask.saved_trap_no = current->thread.trap_no;
124 current->thread.trap_no = UPROBE_TRAP_NR;
125 regs->ARM_pc = utask->xol_vaddr;
130 int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
132 struct uprobe_task *utask = current->utask;
134 WARN_ON_ONCE(current->thread.trap_no != UPROBE_TRAP_NR);
136 current->thread.trap_no = utask->autask.saved_trap_no;
137 regs->ARM_pc = utask->vaddr + 4;
139 if (auprobe->posthandler)
140 auprobe->posthandler(auprobe, &utask->autask, regs);
145 bool arch_uprobe_xol_was_trapped(struct task_struct *t)
147 if (t->thread.trap_no != UPROBE_TRAP_NR)
153 void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
155 struct uprobe_task *utask = current->utask;
157 current->thread.trap_no = utask->autask.saved_trap_no;
158 instruction_pointer_set(regs, utask->vaddr);
161 int arch_uprobe_exception_notify(struct notifier_block *self,
162 unsigned long val, void *data)
167 static int uprobe_trap_handler(struct pt_regs *regs, unsigned int instr)
171 local_irq_save(flags);
173 if (instr == (UPROBE_SWBP_ARM_INSN & 0x0fffffff))
174 uprobe_pre_sstep_notifier(regs);
175 else if (instr == (UPROBE_SS_ARM_INSN & 0x0fffffff))
176 uprobe_post_sstep_notifier(regs);
177 local_irq_restore(flags);
182 unsigned long uprobe_get_swbp_addr(struct pt_regs *regs)
184 return instruction_pointer(regs);
187 static struct undef_hook uprobes_arm_break_hook = {
188 .instr_mask = 0x0fffffff,
189 .instr_val = (UPROBE_SWBP_ARM_INSN & 0x0fffffff),
190 .cpsr_mask = MODE_MASK,
191 .cpsr_val = USR_MODE,
192 .fn = uprobe_trap_handler,
195 static struct undef_hook uprobes_arm_ss_hook = {
196 .instr_mask = 0x0fffffff,
197 .instr_val = (UPROBE_SS_ARM_INSN & 0x0fffffff),
198 .cpsr_mask = MODE_MASK,
199 .cpsr_val = USR_MODE,
200 .fn = uprobe_trap_handler,
203 static int arch_uprobes_init(void)
205 register_undef_hook(&uprobes_arm_break_hook);
206 register_undef_hook(&uprobes_arm_ss_hook);
210 device_initcall(arch_uprobes_init);