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
14bool is_swbp_insn(uprobe_opcode_t *insn)
15{
16	return (*insn & 0xffff) == UPROBE_SWBP_INSN;
17}
18
19unsigned long uprobe_get_swbp_addr(struct pt_regs *regs)
20{
21	return instruction_pointer(regs);
22}
23
24int 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
48int 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
62int 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	current->thread.trap_no = utask->autask.saved_trap_no;
68
69	instruction_pointer_set(regs, utask->vaddr + auprobe->insn_size);
70
71	user_disable_single_step(current);
72
73	return 0;
74}
75
76bool arch_uprobe_xol_was_trapped(struct task_struct *t)
77{
78	if (t->thread.trap_no != UPROBE_TRAP_NR)
79		return true;
80
81	return false;
82}
83
84bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
85{
86	probe_opcode_t insn;
87	unsigned long addr;
88
89	if (!auprobe->simulate)
90		return false;
91
92	insn = *(probe_opcode_t *)(&auprobe->insn[0]);
93	addr = instruction_pointer(regs);
94
95	if (auprobe->api.handler)
96		auprobe->api.handler(insn, addr, regs);
97
98	return true;
99}
100
101void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
102{
103	struct uprobe_task *utask = current->utask;
104
105	current->thread.trap_no = utask->autask.saved_trap_no;
106
107	/*
108	 * Task has received a fatal signal, so reset back to probed
109	 * address.
110	 */
111	instruction_pointer_set(regs, utask->vaddr);
112
113	user_disable_single_step(current);
114}
115
116bool arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx,
117		struct pt_regs *regs)
118{
119	if (ctx == RP_CHECK_CHAIN_CALL)
120		return regs->usp <= ret->stack;
121	else
122		return regs->usp < ret->stack;
123}
124
125unsigned long
126arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr,
127				  struct pt_regs *regs)
128{
129	unsigned long ra;
130
131	ra = regs->lr;
132
133	regs->lr = trampoline_vaddr;
134
135	return ra;
136}
137
138int arch_uprobe_exception_notify(struct notifier_block *self,
139				 unsigned long val, void *data)
140{
141	return NOTIFY_DONE;
142}
143
144int uprobe_breakpoint_handler(struct pt_regs *regs)
145{
146	if (uprobe_pre_sstep_notifier(regs))
147		return 1;
148
149	return 0;
150}
151
152int uprobe_single_step_handler(struct pt_regs *regs)
153{
154	if (uprobe_post_sstep_notifier(regs))
155		return 1;
156
157	return 0;
158}
159