diff options
author | David A. Long <dave.long@linaro.org> | 2014-03-07 11:23:04 -0500 |
---|---|---|
committer | David A. Long <dave.long@linaro.org> | 2014-03-18 16:39:40 -0400 |
commit | c7edc9e326d53ca5ef9bed82de0740c6b107d55b (patch) | |
tree | 262d901b5e4d61930d5bc8ff68b9ddd807e3f956 /arch/arm/kernel/uprobes.c | |
parent | b4cd605ca92d9a8a2f71355cb45dd943ebcb0c97 (diff) |
ARM: add uprobes support
Using Rabin Vincent's ARM uprobes patches as a base, enable uprobes
support on ARM.
Caveats:
- Thumb is not supported
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: David A. Long <dave.long@linaro.org>
Diffstat (limited to 'arch/arm/kernel/uprobes.c')
-rw-r--r-- | arch/arm/kernel/uprobes.c | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/arch/arm/kernel/uprobes.c b/arch/arm/kernel/uprobes.c new file mode 100644 index 000000000000..f9bacee973bf --- /dev/null +++ b/arch/arm/kernel/uprobes.c | |||
@@ -0,0 +1,210 @@ | |||
1 | /* | ||
2 | * Copyright (C) 2012 Rabin Vincent <rabin at rab.in> | ||
3 | * | ||
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. | ||
7 | */ | ||
8 | |||
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> | ||
16 | |||
17 | #include <asm/opcodes.h> | ||
18 | #include <asm/traps.h> | ||
19 | |||
20 | #include "probes.h" | ||
21 | #include "probes-arm.h" | ||
22 | #include "uprobes.h" | ||
23 | |||
24 | #define UPROBE_TRAP_NR UINT_MAX | ||
25 | |||
26 | bool is_swbp_insn(uprobe_opcode_t *insn) | ||
27 | { | ||
28 | return (__mem_to_opcode_arm(*insn) & 0x0fffffff) == | ||
29 | (UPROBE_SWBP_ARM_INSN & 0x0fffffff); | ||
30 | } | ||
31 | |||
32 | int set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, | ||
33 | unsigned long vaddr) | ||
34 | { | ||
35 | return uprobe_write_opcode(mm, vaddr, | ||
36 | __opcode_to_mem_arm(auprobe->bpinsn)); | ||
37 | } | ||
38 | |||
39 | bool arch_uprobe_ignore(struct arch_uprobe *auprobe, struct pt_regs *regs) | ||
40 | { | ||
41 | if (!auprobe->asi.insn_check_cc(regs->ARM_cpsr)) { | ||
42 | regs->ARM_pc += 4; | ||
43 | return true; | ||
44 | } | ||
45 | |||
46 | return false; | ||
47 | } | ||
48 | |||
49 | bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs) | ||
50 | { | ||
51 | probes_opcode_t opcode; | ||
52 | |||
53 | if (!auprobe->simulate) | ||
54 | return false; | ||
55 | |||
56 | opcode = __mem_to_opcode_arm(*(unsigned int *) auprobe->insn); | ||
57 | |||
58 | auprobe->asi.insn_singlestep(opcode, &auprobe->asi, regs); | ||
59 | |||
60 | return true; | ||
61 | } | ||
62 | |||
63 | unsigned long | ||
64 | arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, | ||
65 | struct pt_regs *regs) | ||
66 | { | ||
67 | unsigned long orig_ret_vaddr; | ||
68 | |||
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; | ||
73 | } | ||
74 | |||
75 | int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, | ||
76 | unsigned long addr) | ||
77 | { | ||
78 | unsigned int insn; | ||
79 | unsigned int bpinsn; | ||
80 | enum probes_insn ret; | ||
81 | |||
82 | /* Thumb not yet support */ | ||
83 | if (addr & 0x3) | ||
84 | return -EINVAL; | ||
85 | |||
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); | ||
89 | |||
90 | ret = arm_probes_decode_insn(insn, &auprobe->asi, false, | ||
91 | uprobes_probes_actions); | ||
92 | switch (ret) { | ||
93 | case INSN_REJECTED: | ||
94 | return -EINVAL; | ||
95 | |||
96 | case INSN_GOOD_NO_SLOT: | ||
97 | auprobe->simulate = true; | ||
98 | break; | ||
99 | |||
100 | case INSN_GOOD: | ||
101 | default: | ||
102 | break; | ||
103 | } | ||
104 | |||
105 | bpinsn = UPROBE_SWBP_ARM_INSN & 0x0fffffff; | ||
106 | if (insn >= 0xe0000000) | ||
107 | bpinsn |= 0xe0000000; /* Unconditional instruction */ | ||
108 | else | ||
109 | bpinsn |= insn & 0xf0000000; /* Copy condition from insn */ | ||
110 | |||
111 | auprobe->bpinsn = bpinsn; | ||
112 | |||
113 | return 0; | ||
114 | } | ||
115 | |||
116 | int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) | ||
117 | { | ||
118 | struct uprobe_task *utask = current->utask; | ||
119 | |||
120 | if (auprobe->prehandler) | ||
121 | auprobe->prehandler(auprobe, &utask->autask, regs); | ||
122 | |||
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; | ||
126 | |||
127 | return 0; | ||
128 | } | ||
129 | |||
130 | int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) | ||
131 | { | ||
132 | struct uprobe_task *utask = current->utask; | ||
133 | |||
134 | WARN_ON_ONCE(current->thread.trap_no != UPROBE_TRAP_NR); | ||
135 | |||
136 | current->thread.trap_no = utask->autask.saved_trap_no; | ||
137 | regs->ARM_pc = utask->vaddr + 4; | ||
138 | |||
139 | if (auprobe->posthandler) | ||
140 | auprobe->posthandler(auprobe, &utask->autask, regs); | ||
141 | |||
142 | return 0; | ||
143 | } | ||
144 | |||
145 | bool arch_uprobe_xol_was_trapped(struct task_struct *t) | ||
146 | { | ||
147 | if (t->thread.trap_no != UPROBE_TRAP_NR) | ||
148 | return true; | ||
149 | |||
150 | return false; | ||
151 | } | ||
152 | |||
153 | void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) | ||
154 | { | ||
155 | struct uprobe_task *utask = current->utask; | ||
156 | |||
157 | current->thread.trap_no = utask->autask.saved_trap_no; | ||
158 | instruction_pointer_set(regs, utask->vaddr); | ||
159 | } | ||
160 | |||
161 | int arch_uprobe_exception_notify(struct notifier_block *self, | ||
162 | unsigned long val, void *data) | ||
163 | { | ||
164 | return NOTIFY_DONE; | ||
165 | } | ||
166 | |||
167 | static int uprobe_trap_handler(struct pt_regs *regs, unsigned int instr) | ||
168 | { | ||
169 | unsigned long flags; | ||
170 | |||
171 | local_irq_save(flags); | ||
172 | instr &= 0x0fffffff; | ||
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); | ||
178 | |||
179 | return 0; | ||
180 | } | ||
181 | |||
182 | unsigned long uprobe_get_swbp_addr(struct pt_regs *regs) | ||
183 | { | ||
184 | return instruction_pointer(regs); | ||
185 | } | ||
186 | |||
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, | ||
193 | }; | ||
194 | |||
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, | ||
201 | }; | ||
202 | |||
203 | static int arch_uprobes_init(void) | ||
204 | { | ||
205 | register_undef_hook(&uprobes_arm_break_hook); | ||
206 | register_undef_hook(&uprobes_arm_ss_hook); | ||
207 | |||
208 | return 0; | ||
209 | } | ||
210 | device_initcall(arch_uprobes_init); | ||