1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* kgdb support for ARC
*
* Copyright (C) 2012 Synopsys, Inc. (www.synopsys.com)
*/
#include <linux/kgdb.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <asm/disasm.h>
#include <asm/cacheflush.h>
static void to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs,
struct callee_regs *cregs)
{
int regno;
for (regno = 0; regno <= 26; regno++)
gdb_regs[_R0 + regno] = get_reg(regno, kernel_regs, cregs);
for (regno = 27; regno < GDB_MAX_REGS; regno++)
gdb_regs[regno] = 0;
gdb_regs[_FP] = kernel_regs->fp;
gdb_regs[__SP] = kernel_regs->sp;
gdb_regs[_BLINK] = kernel_regs->blink;
gdb_regs[_RET] = kernel_regs->ret;
gdb_regs[_STATUS32] = kernel_regs->status32;
gdb_regs[_LP_COUNT] = kernel_regs->lp_count;
gdb_regs[_LP_END] = kernel_regs->lp_end;
gdb_regs[_LP_START] = kernel_regs->lp_start;
gdb_regs[_BTA] = kernel_regs->bta;
gdb_regs[_STOP_PC] = kernel_regs->ret;
}
static void from_gdb_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs,
struct callee_regs *cregs)
{
int regno;
for (regno = 0; regno <= 26; regno++)
set_reg(regno, gdb_regs[regno + _R0], kernel_regs, cregs);
kernel_regs->fp = gdb_regs[_FP];
kernel_regs->sp = gdb_regs[__SP];
kernel_regs->blink = gdb_regs[_BLINK];
kernel_regs->ret = gdb_regs[_RET];
kernel_regs->status32 = gdb_regs[_STATUS32];
kernel_regs->lp_count = gdb_regs[_LP_COUNT];
kernel_regs->lp_end = gdb_regs[_LP_END];
kernel_regs->lp_start = gdb_regs[_LP_START];
kernel_regs->bta = gdb_regs[_BTA];
}
void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs)
{
to_gdb_regs(gdb_regs, kernel_regs, (struct callee_regs *)
current->thread.callee_reg);
}
void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs)
{
from_gdb_regs(gdb_regs, kernel_regs, (struct callee_regs *)
current->thread.callee_reg);
}
void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs,
struct task_struct *task)
{
if (task)
to_gdb_regs(gdb_regs, task_pt_regs(task),
(struct callee_regs *) task->thread.callee_reg);
}
struct single_step_data_t {
uint16_t opcode[2];
unsigned long address[2];
int is_branch;
int armed;
} single_step_data;
static void undo_single_step(struct pt_regs *regs)
{
if (single_step_data.armed) {
int i;
for (i = 0; i < (single_step_data.is_branch ? 2 : 1); i++) {
memcpy((void *) single_step_data.address[i],
&single_step_data.opcode[i],
BREAK_INSTR_SIZE);
flush_icache_range(single_step_data.address[i],
single_step_data.address[i] +
BREAK_INSTR_SIZE);
}
single_step_data.armed = 0;
}
}
static void place_trap(unsigned long address, void *save)
{
memcpy(save, (void *) address, BREAK_INSTR_SIZE);
memcpy((void *) address, &arch_kgdb_ops.gdb_bpt_instr,
BREAK_INSTR_SIZE);
flush_icache_range(address, address + BREAK_INSTR_SIZE);
}
static void do_single_step(struct pt_regs *regs)
{
single_step_data.is_branch = disasm_next_pc((unsigned long)
regs->ret, regs, (struct callee_regs *)
current->thread.callee_reg,
&single_step_data.address[0],
&single_step_data.address[1]);
place_trap(single_step_data.address[0], &single_step_data.opcode[0]);
if (single_step_data.is_branch) {
place_trap(single_step_data.address[1],
&single_step_data.opcode[1]);
}
single_step_data.armed++;
}
int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
char *remcomInBuffer, char *remcomOutBuffer,
struct pt_regs *regs)
{
unsigned long addr;
char *ptr;
undo_single_step(regs);
switch (remcomInBuffer[0]) {
case 's':
case 'c':
ptr = &remcomInBuffer[1];
if (kgdb_hex2long(&ptr, &addr))
regs->ret = addr;
fallthrough;
case 'D':
case 'k':
atomic_set(&kgdb_cpu_doing_single_step, -1);
if (remcomInBuffer[0] == 's') {
do_single_step(regs);
atomic_set(&kgdb_cpu_doing_single_step,
smp_processor_id());
}
return 0;
}
return -1;
}
int kgdb_arch_init(void)
{
single_step_data.armed = 0;
return 0;
}
void kgdb_trap(struct pt_regs *regs)
{
/* trap_s 3 is used for breakpoints that overwrite existing
* instructions, while trap_s 4 is used for compiled breakpoints.
*
* with trap_s 3 breakpoints the original instruction needs to be
* restored and continuation needs to start at the location of the
* breakpoint.
*
* with trap_s 4 (compiled) breakpoints, continuation needs to
* start after the breakpoint.
*/
if (regs->ecr_param == 3)
instruction_pointer(regs) -= BREAK_INSTR_SIZE;
kgdb_handle_exception(1, SIGTRAP, 0, regs);
}
void kgdb_arch_exit(void)
{
}
void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
{
instruction_pointer(regs) = ip;
}
void kgdb_call_nmi_hook(void *ignored)
{
/* Default implementation passes get_irq_regs() but we don't */
kgdb_nmicallback(raw_smp_processor_id(), NULL);
}
const struct kgdb_arch arch_kgdb_ops = {
/* breakpoint instruction: TRAP_S 0x3 */
#ifdef CONFIG_CPU_BIG_ENDIAN
.gdb_bpt_instr = {0x78, 0x7e},
#else
.gdb_bpt_instr = {0x7e, 0x78},
#endif
};
|
