1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * arch/hexagon/kernel/kgdb.c - Hexagon KGDB Support
4 *
5 * Copyright (c) 2011-2012, The Linux Foundation. All rights reserved.
6 */
7
8 #include <linux/irq.h>
9 #include <linux/sched.h>
10 #include <linux/sched/task_stack.h>
11 #include <linux/kdebug.h>
12 #include <linux/kgdb.h>
13
14 /* All registers are 4 bytes, for now */
15 #define GDB_SIZEOF_REG 4
16
17 /* The register names are used during printing of the regs;
18 * Keep these at three letters to pretty-print. */
19 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = {
20 { " r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, r00)},
21 { " r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, r01)},
22 { " r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, r02)},
23 { " r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, r03)},
24 { " r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, r04)},
25 { " r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, r05)},
26 { " r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, r06)},
27 { " r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, r07)},
28 { " r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, r08)},
29 { " r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, r09)},
30 { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, r10)},
31 { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, r11)},
32 { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, r12)},
33 { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, r13)},
34 { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, r14)},
35 { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, r15)},
36 { "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, r16)},
37 { "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, r17)},
38 { "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, r18)},
39 { "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, r19)},
40 { "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, r20)},
41 { "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, r21)},
42 { "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, r22)},
43 { "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, r23)},
44 { "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, r24)},
45 { "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, r25)},
46 { "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, r26)},
47 { "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, r27)},
48 { "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, r28)},
49 { "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, r29)},
50 { "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, r30)},
51 { "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, r31)},
52
53 { "usr", GDB_SIZEOF_REG, offsetof(struct pt_regs, usr)},
54 { "preds", GDB_SIZEOF_REG, offsetof(struct pt_regs, preds)},
55 { " m0", GDB_SIZEOF_REG, offsetof(struct pt_regs, m0)},
56 { " m1", GDB_SIZEOF_REG, offsetof(struct pt_regs, m1)},
57 { "sa0", GDB_SIZEOF_REG, offsetof(struct pt_regs, sa0)},
58 { "sa1", GDB_SIZEOF_REG, offsetof(struct pt_regs, sa1)},
59 { "lc0", GDB_SIZEOF_REG, offsetof(struct pt_regs, lc0)},
60 { "lc1", GDB_SIZEOF_REG, offsetof(struct pt_regs, lc1)},
61 { " gp", GDB_SIZEOF_REG, offsetof(struct pt_regs, gp)},
62 { "ugp", GDB_SIZEOF_REG, offsetof(struct pt_regs, ugp)},
63 { "cs0", GDB_SIZEOF_REG, offsetof(struct pt_regs, cs0)},
64 { "cs1", GDB_SIZEOF_REG, offsetof(struct pt_regs, cs1)},
65 { "psp", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmpsp)},
66 { "elr", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmel)},
67 { "est", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmest)},
68 { "badva", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmbadva)},
69 { "restart_r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, restart_r0)},
70 { "syscall_nr", GDB_SIZEOF_REG, offsetof(struct pt_regs, syscall_nr)},
71 };
72
73 const struct kgdb_arch arch_kgdb_ops = {
74 /* trap0(#0xDB) 0x0cdb0054 */
75 .gdb_bpt_instr = {0x54, 0x00, 0xdb, 0x0c},
76 };
77
78 char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
79 {
80 if (regno >= DBG_MAX_REG_NUM || regno < 0)
81 return NULL;
82
83 *((unsigned long *) mem) = *((unsigned long *) ((void *)regs +
84 dbg_reg_def[regno].offset));
85
86 return dbg_reg_def[regno].name;
87 }
88
89 int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
90 {
91 if (regno >= DBG_MAX_REG_NUM || regno < 0)
92 return -EINVAL;
93
94 *((unsigned long *) ((void *)regs + dbg_reg_def[regno].offset)) =
95 *((unsigned long *) mem);
96
97 return 0;
98 }
99
100 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
101 {
102 instruction_pointer(regs) = pc;
103 }
104
105
106 /* Not yet working */
107 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs,
108 struct task_struct *task)
109 {
110 struct pt_regs *thread_regs;
111
112 if (task == NULL)
113 return;
114
115 /* Initialize to zero */
116 memset(gdb_regs, 0, NUMREGBYTES);
117
118 /* Otherwise, we have only some registers from switch_to() */
119 thread_regs = task_pt_regs(task);
120 gdb_regs[0] = thread_regs->r00;
121 }
122
123 /**
124 * kgdb_arch_handle_exception - Handle architecture specific GDB packets.
125 * @vector: The error vector of the exception that happened.
126 * @signo: The signal number of the exception that happened.
127 * @err_code: The error code of the exception that happened.
128 * @remcom_in_buffer: The buffer of the packet we have read.
129 * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
130 * @regs: The &struct pt_regs of the current process.
131 *
132 * This function MUST handle the 'c' and 's' command packets,
133 * as well packets to set / remove a hardware breakpoint, if used.
134 * If there are additional packets which the hardware needs to handle,
135 * they are handled here. The code should return -1 if it wants to
136 * process more packets, and a %0 or %1 if it wants to exit from the
137 * kgdb callback.
138 *
139 * Not yet working.
140 */
141 int kgdb_arch_handle_exception(int vector, int signo, int err_code,
142 char *remcom_in_buffer, char *remcom_out_buffer,
143 struct pt_regs *linux_regs)
144 {
145 switch (remcom_in_buffer[0]) {
146 case 's':
147 case 'c':
148 return 0;
149 }
150 /* Stay in the debugger. */
151 return -1;
152 }
153
154 static int __kgdb_notify(struct die_args *args, unsigned long cmd)
155 {
156 /* cpu roundup */
157 if (atomic_read(&kgdb_active) != -1) {
158 kgdb_nmicallback(smp_processor_id(), args->regs);
159 return NOTIFY_STOP;
160 }
161
162 if (user_mode(args->regs))
163 return NOTIFY_DONE;
164
165 if (kgdb_handle_exception(args->trapnr & 0xff, args->signr, args->err,
166 args->regs))
167 return NOTIFY_DONE;
168
169 return NOTIFY_STOP;
170 }
171
172 static int
173 kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
174 {
175 unsigned long flags;
176 int ret;
177
178 local_irq_save(flags);
179 ret = __kgdb_notify(ptr, cmd);
180 local_irq_restore(flags);
181
182 return ret;
183 }
184
185 static struct notifier_block kgdb_notifier = {
186 .notifier_call = kgdb_notify,
187
188 /*
189 * Lowest-prio notifier priority, we want to be notified last:
190 */
191 .priority = -INT_MAX,
192 };
193
194 /**
195 * kgdb_arch_init - Perform any architecture specific initialization.
196 *
197 * This function will handle the initialization of any architecture
198 * specific callbacks.
199 */
200 int kgdb_arch_init(void)
201 {
202 return register_die_notifier(&kgdb_notifier);
203 }
204
205 /**
206 * kgdb_arch_exit - Perform any architecture specific uninitalization.
207 *
208 * This function will handle the uninitalization of any architecture
209 * specific callbacks, for dynamic registration and unregistration.
210 */
211 void kgdb_arch_exit(void)
212 {
213 unregister_die_notifier(&kgdb_notifier);
214 }
215
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