1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2014-2016 Pratyush Anand <panand@redhat.com>
4 */
5 #include <linux/highmem.h>
6 #include <linux/ptrace.h>
7 #include <linux/uprobes.h>
8 #include <asm/cacheflush.h>
9
10 #include "decode-insn.h"
11
12 #define UPROBE_TRAP_NR UINT_MAX
13
is_swbp_insn(uprobe_opcode_t * insn)14 bool is_swbp_insn(uprobe_opcode_t *insn)
15 {
16 return (*insn & 0xffff) == UPROBE_SWBP_INSN;
17 }
18
uprobe_get_swbp_addr(struct pt_regs * regs)19 unsigned long uprobe_get_swbp_addr(struct pt_regs *regs)
20 {
21 return instruction_pointer(regs);
22 }
23
arch_uprobe_analyze_insn(struct arch_uprobe * auprobe,struct mm_struct * mm,unsigned long addr)24 int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
25 unsigned long addr)
26 {
27 probe_opcode_t insn;
28
29 insn = *(probe_opcode_t *)(&auprobe->insn[0]);
30
31 auprobe->insn_size = is_insn32(insn) ? 4 : 2;
32
33 switch (csky_probe_decode_insn(&insn, &auprobe->api)) {
34 case INSN_REJECTED:
35 return -EINVAL;
36
37 case INSN_GOOD_NO_SLOT:
38 auprobe->simulate = true;
39 break;
40
41 default:
42 break;
43 }
44
45 return 0;
46 }
47
arch_uprobe_pre_xol(struct arch_uprobe * auprobe,struct pt_regs * regs)48 int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
49 {
50 struct uprobe_task *utask = current->utask;
51
52 utask->autask.saved_trap_no = current->thread.trap_no;
53 current->thread.trap_no = UPROBE_TRAP_NR;
54
55 instruction_pointer_set(regs, utask->xol_vaddr);
56
57 user_enable_single_step(current);
58
59 return 0;
60 }
61
arch_uprobe_post_xol(struct arch_uprobe * auprobe,struct pt_regs * regs)62 int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
63 {
64 struct uprobe_task *utask = current->utask;
65
66 WARN_ON_ONCE(current->thread.trap_no != UPROBE_TRAP_NR);
67
68 instruction_pointer_set(regs, utask->vaddr + auprobe->insn_size);
69
70 user_disable_single_step(current);
71
72 return 0;
73 }
74
arch_uprobe_xol_was_trapped(struct task_struct * t)75 bool arch_uprobe_xol_was_trapped(struct task_struct *t)
76 {
77 if (t->thread.trap_no != UPROBE_TRAP_NR)
78 return true;
79
80 return false;
81 }
82
arch_uprobe_skip_sstep(struct arch_uprobe * auprobe,struct pt_regs * regs)83 bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
84 {
85 probe_opcode_t insn;
86 unsigned long addr;
87
88 if (!auprobe->simulate)
89 return false;
90
91 insn = *(probe_opcode_t *)(&auprobe->insn[0]);
92 addr = instruction_pointer(regs);
93
94 if (auprobe->api.handler)
95 auprobe->api.handler(insn, addr, regs);
96
97 return true;
98 }
99
arch_uprobe_abort_xol(struct arch_uprobe * auprobe,struct pt_regs * regs)100 void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
101 {
102 struct uprobe_task *utask = current->utask;
103
104 /*
105 * Task has received a fatal signal, so reset back to probbed
106 * address.
107 */
108 instruction_pointer_set(regs, utask->vaddr);
109
110 user_disable_single_step(current);
111 }
112
arch_uretprobe_is_alive(struct return_instance * ret,enum rp_check ctx,struct pt_regs * regs)113 bool arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx,
114 struct pt_regs *regs)
115 {
116 if (ctx == RP_CHECK_CHAIN_CALL)
117 return regs->usp <= ret->stack;
118 else
119 return regs->usp < ret->stack;
120 }
121
122 unsigned long
arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr,struct pt_regs * regs)123 arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr,
124 struct pt_regs *regs)
125 {
126 unsigned long ra;
127
128 ra = regs->lr;
129
130 regs->lr = trampoline_vaddr;
131
132 return ra;
133 }
134
arch_uprobe_exception_notify(struct notifier_block * self,unsigned long val,void * data)135 int arch_uprobe_exception_notify(struct notifier_block *self,
136 unsigned long val, void *data)
137 {
138 return NOTIFY_DONE;
139 }
140
uprobe_breakpoint_handler(struct pt_regs * regs)141 int uprobe_breakpoint_handler(struct pt_regs *regs)
142 {
143 if (uprobe_pre_sstep_notifier(regs))
144 return 1;
145
146 return 0;
147 }
148
uprobe_single_step_handler(struct pt_regs * regs)149 int uprobe_single_step_handler(struct pt_regs *regs)
150 {
151 if (uprobe_post_sstep_notifier(regs))
152 return 1;
153
154 return 0;
155 }
156