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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 "../decode.h"
21#include "../decode-arm.h"
22#include "core.h"
23
24#define UPROBE_TRAP_NR UINT_MAX
25
26bool is_swbp_insn(uprobe_opcode_t *insn)
27{
28 return (__mem_to_opcode_arm(*insn) & 0x0fffffff) ==
29 (UPROBE_SWBP_ARM_INSN & 0x0fffffff);
30}
31
32int 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
39bool 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
49bool 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
63unsigned long
64arch_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
75int 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, NULL);
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
116void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,
117 void *src, unsigned long len)
118{
119 void *xol_page_kaddr = kmap_atomic(page);
120 void *dst = xol_page_kaddr + (vaddr & ~PAGE_MASK);
121
122 preempt_disable();
123
124 /* Initialize the slot */
125 memcpy(dst, src, len);
126
127 /* flush caches (dcache/icache) */
128 flush_uprobe_xol_access(page, vaddr, dst, len);
129
130 preempt_enable();
131
132 kunmap_atomic(xol_page_kaddr);
133}
134
135
136int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
137{
138 struct uprobe_task *utask = current->utask;
139
140 if (auprobe->prehandler)
141 auprobe->prehandler(auprobe, &utask->autask, regs);
142
143 utask->autask.saved_trap_no = current->thread.trap_no;
144 current->thread.trap_no = UPROBE_TRAP_NR;
145 regs->ARM_pc = utask->xol_vaddr;
146
147 return 0;
148}
149
150int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
151{
152 struct uprobe_task *utask = current->utask;
153
154 WARN_ON_ONCE(current->thread.trap_no != UPROBE_TRAP_NR);
155
156 current->thread.trap_no = utask->autask.saved_trap_no;
157 regs->ARM_pc = utask->vaddr + 4;
158
159 if (auprobe->posthandler)
160 auprobe->posthandler(auprobe, &utask->autask, regs);
161
162 return 0;
163}
164
165bool arch_uprobe_xol_was_trapped(struct task_struct *t)
166{
167 if (t->thread.trap_no != UPROBE_TRAP_NR)
168 return true;
169
170 return false;
171}
172
173void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
174{
175 struct uprobe_task *utask = current->utask;
176
177 current->thread.trap_no = utask->autask.saved_trap_no;
178 instruction_pointer_set(regs, utask->vaddr);
179}
180
181int arch_uprobe_exception_notify(struct notifier_block *self,
182 unsigned long val, void *data)
183{
184 return NOTIFY_DONE;
185}
186
187static int uprobe_trap_handler(struct pt_regs *regs, unsigned int instr)
188{
189 unsigned long flags;
190
191 local_irq_save(flags);
192 instr &= 0x0fffffff;
193 if (instr == (UPROBE_SWBP_ARM_INSN & 0x0fffffff))
194 uprobe_pre_sstep_notifier(regs);
195 else if (instr == (UPROBE_SS_ARM_INSN & 0x0fffffff))
196 uprobe_post_sstep_notifier(regs);
197 local_irq_restore(flags);
198
199 return 0;
200}
201
202unsigned long uprobe_get_swbp_addr(struct pt_regs *regs)
203{
204 return instruction_pointer(regs);
205}
206
207static struct undef_hook uprobes_arm_break_hook = {
208 .instr_mask = 0x0fffffff,
209 .instr_val = (UPROBE_SWBP_ARM_INSN & 0x0fffffff),
210 .cpsr_mask = MODE_MASK,
211 .cpsr_val = USR_MODE,
212 .fn = uprobe_trap_handler,
213};
214
215static struct undef_hook uprobes_arm_ss_hook = {
216 .instr_mask = 0x0fffffff,
217 .instr_val = (UPROBE_SS_ARM_INSN & 0x0fffffff),
218 .cpsr_mask = MODE_MASK,
219 .cpsr_val = USR_MODE,
220 .fn = uprobe_trap_handler,
221};
222
223static int arch_uprobes_init(void)
224{
225 register_undef_hook(&uprobes_arm_break_hook);
226 register_undef_hook(&uprobes_arm_ss_hook);
227
228 return 0;
229}
230device_initcall(arch_uprobes_init);
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 "../decode.h"
21#include "../decode-arm.h"
22#include "core.h"
23
24#define UPROBE_TRAP_NR UINT_MAX
25
26bool is_swbp_insn(uprobe_opcode_t *insn)
27{
28 return (__mem_to_opcode_arm(*insn) & 0x0fffffff) ==
29 (UPROBE_SWBP_ARM_INSN & 0x0fffffff);
30}
31
32int 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
39bool 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
49bool 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
63unsigned long
64arch_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
75int 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, NULL);
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
116void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,
117 void *src, unsigned long len)
118{
119 void *xol_page_kaddr = kmap_atomic(page);
120 void *dst = xol_page_kaddr + (vaddr & ~PAGE_MASK);
121
122 preempt_disable();
123
124 /* Initialize the slot */
125 memcpy(dst, src, len);
126
127 /* flush caches (dcache/icache) */
128 flush_uprobe_xol_access(page, vaddr, dst, len);
129
130 preempt_enable();
131
132 kunmap_atomic(xol_page_kaddr);
133}
134
135
136int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
137{
138 struct uprobe_task *utask = current->utask;
139
140 if (auprobe->prehandler)
141 auprobe->prehandler(auprobe, &utask->autask, regs);
142
143 utask->autask.saved_trap_no = current->thread.trap_no;
144 current->thread.trap_no = UPROBE_TRAP_NR;
145 regs->ARM_pc = utask->xol_vaddr;
146
147 return 0;
148}
149
150int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
151{
152 struct uprobe_task *utask = current->utask;
153
154 WARN_ON_ONCE(current->thread.trap_no != UPROBE_TRAP_NR);
155
156 current->thread.trap_no = utask->autask.saved_trap_no;
157 regs->ARM_pc = utask->vaddr + 4;
158
159 if (auprobe->posthandler)
160 auprobe->posthandler(auprobe, &utask->autask, regs);
161
162 return 0;
163}
164
165bool arch_uprobe_xol_was_trapped(struct task_struct *t)
166{
167 if (t->thread.trap_no != UPROBE_TRAP_NR)
168 return true;
169
170 return false;
171}
172
173void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
174{
175 struct uprobe_task *utask = current->utask;
176
177 current->thread.trap_no = utask->autask.saved_trap_no;
178 instruction_pointer_set(regs, utask->vaddr);
179}
180
181int arch_uprobe_exception_notify(struct notifier_block *self,
182 unsigned long val, void *data)
183{
184 return NOTIFY_DONE;
185}
186
187static int uprobe_trap_handler(struct pt_regs *regs, unsigned int instr)
188{
189 unsigned long flags;
190
191 local_irq_save(flags);
192 instr &= 0x0fffffff;
193 if (instr == (UPROBE_SWBP_ARM_INSN & 0x0fffffff))
194 uprobe_pre_sstep_notifier(regs);
195 else if (instr == (UPROBE_SS_ARM_INSN & 0x0fffffff))
196 uprobe_post_sstep_notifier(regs);
197 local_irq_restore(flags);
198
199 return 0;
200}
201
202unsigned long uprobe_get_swbp_addr(struct pt_regs *regs)
203{
204 return instruction_pointer(regs);
205}
206
207static struct undef_hook uprobes_arm_break_hook = {
208 .instr_mask = 0x0fffffff,
209 .instr_val = (UPROBE_SWBP_ARM_INSN & 0x0fffffff),
210 .cpsr_mask = MODE_MASK,
211 .cpsr_val = USR_MODE,
212 .fn = uprobe_trap_handler,
213};
214
215static struct undef_hook uprobes_arm_ss_hook = {
216 .instr_mask = 0x0fffffff,
217 .instr_val = (UPROBE_SS_ARM_INSN & 0x0fffffff),
218 .cpsr_mask = MODE_MASK,
219 .cpsr_val = USR_MODE,
220 .fn = uprobe_trap_handler,
221};
222
223static int arch_uprobes_init(void)
224{
225 register_undef_hook(&uprobes_arm_break_hook);
226 register_undef_hook(&uprobes_arm_ss_hook);
227
228 return 0;
229}
230device_initcall(arch_uprobes_init);