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6#include <linux/ptrace.h>
7#include <linux/kdebug.h>
8#include <linux/bug.h>
9#include <linux/kgdb.h>
10#include <linux/irqflags.h>
11#include <linux/string.h>
12#include <asm/cacheflush.h>
13#include <asm/gdb_xml.h>
14#include <asm/parse_asm.h>
15
16enum {
17 NOT_KGDB_BREAK = 0,
18 KGDB_SW_BREAK,
19 KGDB_COMPILED_BREAK,
20 KGDB_SW_SINGLE_STEP
21};
22
23static unsigned long stepped_address;
24static unsigned int stepped_opcode;
25
26#if __riscv_xlen == 32
27
28DECLARE_INSN(c_jal, MATCH_C_JAL, MASK_C_JAL)
29#else
30#define is_c_jal_insn(opcode) 0
31#endif
32DECLARE_INSN(jalr, MATCH_JALR, MASK_JALR)
33DECLARE_INSN(jal, MATCH_JAL, MASK_JAL)
34DECLARE_INSN(c_jr, MATCH_C_JR, MASK_C_JR)
35DECLARE_INSN(c_jalr, MATCH_C_JALR, MASK_C_JALR)
36DECLARE_INSN(c_j, MATCH_C_J, MASK_C_J)
37DECLARE_INSN(beq, MATCH_BEQ, MASK_BEQ)
38DECLARE_INSN(bne, MATCH_BNE, MASK_BNE)
39DECLARE_INSN(blt, MATCH_BLT, MASK_BLT)
40DECLARE_INSN(bge, MATCH_BGE, MASK_BGE)
41DECLARE_INSN(bltu, MATCH_BLTU, MASK_BLTU)
42DECLARE_INSN(bgeu, MATCH_BGEU, MASK_BGEU)
43DECLARE_INSN(c_beqz, MATCH_C_BEQZ, MASK_C_BEQZ)
44DECLARE_INSN(c_bnez, MATCH_C_BNEZ, MASK_C_BNEZ)
45DECLARE_INSN(sret, MATCH_SRET, MASK_SRET)
46
47static int decode_register_index(unsigned long opcode, int offset)
48{
49 return (opcode >> offset) & 0x1F;
50}
51
52static int decode_register_index_short(unsigned long opcode, int offset)
53{
54 return ((opcode >> offset) & 0x7) + 8;
55}
56
57
58static int get_step_address(struct pt_regs *regs, unsigned long *next_addr)
59{
60 unsigned long pc = regs->epc;
61 unsigned long *regs_ptr = (unsigned long *)regs;
62 unsigned int rs1_num, rs2_num;
63 int op_code;
64
65 if (get_kernel_nofault(op_code, (void *)pc))
66 return -EINVAL;
67 if ((op_code & __INSN_LENGTH_MASK) != __INSN_LENGTH_GE_32) {
68 if (is_c_jalr_insn(op_code) || is_c_jr_insn(op_code)) {
69 rs1_num = decode_register_index(op_code, RVC_C2_RS1_OPOFF);
70 *next_addr = regs_ptr[rs1_num];
71 } else if (is_c_j_insn(op_code) || is_c_jal_insn(op_code)) {
72 *next_addr = EXTRACT_RVC_J_IMM(op_code) + pc;
73 } else if (is_c_beqz_insn(op_code)) {
74 rs1_num = decode_register_index_short(op_code,
75 RVC_C1_RS1_OPOFF);
76 if (!rs1_num || regs_ptr[rs1_num] == 0)
77 *next_addr = EXTRACT_RVC_B_IMM(op_code) + pc;
78 else
79 *next_addr = pc + 2;
80 } else if (is_c_bnez_insn(op_code)) {
81 rs1_num =
82 decode_register_index_short(op_code, RVC_C1_RS1_OPOFF);
83 if (rs1_num && regs_ptr[rs1_num] != 0)
84 *next_addr = EXTRACT_RVC_B_IMM(op_code) + pc;
85 else
86 *next_addr = pc + 2;
87 } else {
88 *next_addr = pc + 2;
89 }
90 } else {
91 if ((op_code & __INSN_OPCODE_MASK) == __INSN_BRANCH_OPCODE) {
92 bool result = false;
93 long imm = EXTRACT_BTYPE_IMM(op_code);
94 unsigned long rs1_val = 0, rs2_val = 0;
95
96 rs1_num = decode_register_index(op_code, RVG_RS1_OPOFF);
97 rs2_num = decode_register_index(op_code, RVG_RS2_OPOFF);
98 if (rs1_num)
99 rs1_val = regs_ptr[rs1_num];
100 if (rs2_num)
101 rs2_val = regs_ptr[rs2_num];
102
103 if (is_beq_insn(op_code))
104 result = (rs1_val == rs2_val) ? true : false;
105 else if (is_bne_insn(op_code))
106 result = (rs1_val != rs2_val) ? true : false;
107 else if (is_blt_insn(op_code))
108 result =
109 ((long)rs1_val <
110 (long)rs2_val) ? true : false;
111 else if (is_bge_insn(op_code))
112 result =
113 ((long)rs1_val >=
114 (long)rs2_val) ? true : false;
115 else if (is_bltu_insn(op_code))
116 result = (rs1_val < rs2_val) ? true : false;
117 else if (is_bgeu_insn(op_code))
118 result = (rs1_val >= rs2_val) ? true : false;
119 if (result)
120 *next_addr = imm + pc;
121 else
122 *next_addr = pc + 4;
123 } else if (is_jal_insn(op_code)) {
124 *next_addr = EXTRACT_JTYPE_IMM(op_code) + pc;
125 } else if (is_jalr_insn(op_code)) {
126 rs1_num = decode_register_index(op_code, RVG_RS1_OPOFF);
127 if (rs1_num)
128 *next_addr = ((unsigned long *)regs)[rs1_num];
129 *next_addr += EXTRACT_ITYPE_IMM(op_code);
130 } else if (is_sret_insn(op_code)) {
131 *next_addr = pc;
132 } else {
133 *next_addr = pc + 4;
134 }
135 }
136 return 0;
137}
138
139static int do_single_step(struct pt_regs *regs)
140{
141
142 unsigned long addr = 0;
143 int error = get_step_address(regs, &addr);
144
145 if (error)
146 return error;
147
148
149 error = get_kernel_nofault(stepped_opcode, (void *)addr);
150 if (error)
151 return error;
152
153 stepped_address = addr;
154
155
156 error = copy_to_kernel_nofault((void *)stepped_address,
157 arch_kgdb_ops.gdb_bpt_instr,
158 BREAK_INSTR_SIZE);
159
160 if (!error) {
161 flush_icache_range(addr, addr + BREAK_INSTR_SIZE);
162 kgdb_single_step = 1;
163 atomic_set(&kgdb_cpu_doing_single_step,
164 raw_smp_processor_id());
165 } else {
166 stepped_address = 0;
167 stepped_opcode = 0;
168 }
169 return error;
170}
171
172
173static void undo_single_step(struct pt_regs *regs)
174{
175 if (stepped_opcode != 0) {
176 copy_to_kernel_nofault((void *)stepped_address,
177 (void *)&stepped_opcode, BREAK_INSTR_SIZE);
178 flush_icache_range(stepped_address,
179 stepped_address + BREAK_INSTR_SIZE);
180 }
181 stepped_address = 0;
182 stepped_opcode = 0;
183 kgdb_single_step = 0;
184 atomic_set(&kgdb_cpu_doing_single_step, -1);
185}
186
187struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = {
188 {DBG_REG_ZERO, GDB_SIZEOF_REG, -1},
189 {DBG_REG_RA, GDB_SIZEOF_REG, offsetof(struct pt_regs, ra)},
190 {DBG_REG_SP, GDB_SIZEOF_REG, offsetof(struct pt_regs, sp)},
191 {DBG_REG_GP, GDB_SIZEOF_REG, offsetof(struct pt_regs, gp)},
192 {DBG_REG_TP, GDB_SIZEOF_REG, offsetof(struct pt_regs, tp)},
193 {DBG_REG_T0, GDB_SIZEOF_REG, offsetof(struct pt_regs, t0)},
194 {DBG_REG_T1, GDB_SIZEOF_REG, offsetof(struct pt_regs, t1)},
195 {DBG_REG_T2, GDB_SIZEOF_REG, offsetof(struct pt_regs, t2)},
196 {DBG_REG_FP, GDB_SIZEOF_REG, offsetof(struct pt_regs, s0)},
197 {DBG_REG_S1, GDB_SIZEOF_REG, offsetof(struct pt_regs, a1)},
198 {DBG_REG_A0, GDB_SIZEOF_REG, offsetof(struct pt_regs, a0)},
199 {DBG_REG_A1, GDB_SIZEOF_REG, offsetof(struct pt_regs, a1)},
200 {DBG_REG_A2, GDB_SIZEOF_REG, offsetof(struct pt_regs, a2)},
201 {DBG_REG_A3, GDB_SIZEOF_REG, offsetof(struct pt_regs, a3)},
202 {DBG_REG_A4, GDB_SIZEOF_REG, offsetof(struct pt_regs, a4)},
203 {DBG_REG_A5, GDB_SIZEOF_REG, offsetof(struct pt_regs, a5)},
204 {DBG_REG_A6, GDB_SIZEOF_REG, offsetof(struct pt_regs, a6)},
205 {DBG_REG_A7, GDB_SIZEOF_REG, offsetof(struct pt_regs, a7)},
206 {DBG_REG_S2, GDB_SIZEOF_REG, offsetof(struct pt_regs, s2)},
207 {DBG_REG_S3, GDB_SIZEOF_REG, offsetof(struct pt_regs, s3)},
208 {DBG_REG_S4, GDB_SIZEOF_REG, offsetof(struct pt_regs, s4)},
209 {DBG_REG_S5, GDB_SIZEOF_REG, offsetof(struct pt_regs, s5)},
210 {DBG_REG_S6, GDB_SIZEOF_REG, offsetof(struct pt_regs, s6)},
211 {DBG_REG_S7, GDB_SIZEOF_REG, offsetof(struct pt_regs, s7)},
212 {DBG_REG_S8, GDB_SIZEOF_REG, offsetof(struct pt_regs, s8)},
213 {DBG_REG_S9, GDB_SIZEOF_REG, offsetof(struct pt_regs, s9)},
214 {DBG_REG_S10, GDB_SIZEOF_REG, offsetof(struct pt_regs, s10)},
215 {DBG_REG_S11, GDB_SIZEOF_REG, offsetof(struct pt_regs, s11)},
216 {DBG_REG_T3, GDB_SIZEOF_REG, offsetof(struct pt_regs, t3)},
217 {DBG_REG_T4, GDB_SIZEOF_REG, offsetof(struct pt_regs, t4)},
218 {DBG_REG_T5, GDB_SIZEOF_REG, offsetof(struct pt_regs, t5)},
219 {DBG_REG_T6, GDB_SIZEOF_REG, offsetof(struct pt_regs, t6)},
220 {DBG_REG_EPC, GDB_SIZEOF_REG, offsetof(struct pt_regs, epc)},
221 {DBG_REG_STATUS, GDB_SIZEOF_REG, offsetof(struct pt_regs, status)},
222 {DBG_REG_BADADDR, GDB_SIZEOF_REG, offsetof(struct pt_regs, badaddr)},
223 {DBG_REG_CAUSE, GDB_SIZEOF_REG, offsetof(struct pt_regs, cause)},
224};
225
226char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
227{
228 if (regno >= DBG_MAX_REG_NUM || regno < 0)
229 return NULL;
230
231 if (dbg_reg_def[regno].offset != -1)
232 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
233 dbg_reg_def[regno].size);
234 else
235 memset(mem, 0, dbg_reg_def[regno].size);
236 return dbg_reg_def[regno].name;
237}
238
239int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
240{
241 if (regno >= DBG_MAX_REG_NUM || regno < 0)
242 return -EINVAL;
243
244 if (dbg_reg_def[regno].offset != -1)
245 memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
246 dbg_reg_def[regno].size);
247 return 0;
248}
249
250void
251sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task)
252{
253
254 memset((char *)gdb_regs, 0, NUMREGBYTES);
255
256 gdb_regs[DBG_REG_SP_OFF] = task->thread.sp;
257 gdb_regs[DBG_REG_FP_OFF] = task->thread.s[0];
258 gdb_regs[DBG_REG_S1_OFF] = task->thread.s[1];
259 gdb_regs[DBG_REG_S2_OFF] = task->thread.s[2];
260 gdb_regs[DBG_REG_S3_OFF] = task->thread.s[3];
261 gdb_regs[DBG_REG_S4_OFF] = task->thread.s[4];
262 gdb_regs[DBG_REG_S5_OFF] = task->thread.s[5];
263 gdb_regs[DBG_REG_S6_OFF] = task->thread.s[6];
264 gdb_regs[DBG_REG_S7_OFF] = task->thread.s[7];
265 gdb_regs[DBG_REG_S8_OFF] = task->thread.s[8];
266 gdb_regs[DBG_REG_S9_OFF] = task->thread.s[10];
267 gdb_regs[DBG_REG_S10_OFF] = task->thread.s[11];
268 gdb_regs[DBG_REG_EPC_OFF] = task->thread.ra;
269}
270
271void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
272{
273 regs->epc = pc;
274}
275
276void kgdb_arch_handle_qxfer_pkt(char *remcom_in_buffer,
277 char *remcom_out_buffer)
278{
279 if (!strncmp(remcom_in_buffer, gdb_xfer_read_target,
280 sizeof(gdb_xfer_read_target)))
281 strcpy(remcom_out_buffer, riscv_gdb_stub_target_desc);
282 else if (!strncmp(remcom_in_buffer, gdb_xfer_read_cpuxml,
283 sizeof(gdb_xfer_read_cpuxml)))
284 strcpy(remcom_out_buffer, riscv_gdb_stub_cpuxml);
285}
286
287static inline void kgdb_arch_update_addr(struct pt_regs *regs,
288 char *remcom_in_buffer)
289{
290 unsigned long addr;
291 char *ptr;
292
293 ptr = &remcom_in_buffer[1];
294 if (kgdb_hex2long(&ptr, &addr))
295 regs->epc = addr;
296}
297
298int kgdb_arch_handle_exception(int vector, int signo, int err_code,
299 char *remcom_in_buffer, char *remcom_out_buffer,
300 struct pt_regs *regs)
301{
302 int err = 0;
303
304 undo_single_step(regs);
305
306 switch (remcom_in_buffer[0]) {
307 case 'c':
308 case 'D':
309 case 'k':
310 if (remcom_in_buffer[0] == 'c')
311 kgdb_arch_update_addr(regs, remcom_in_buffer);
312 break;
313 case 's':
314 kgdb_arch_update_addr(regs, remcom_in_buffer);
315 err = do_single_step(regs);
316 break;
317 default:
318 err = -1;
319 }
320 return err;
321}
322
323static int kgdb_riscv_kgdbbreak(unsigned long addr)
324{
325 if (stepped_address == addr)
326 return KGDB_SW_SINGLE_STEP;
327 if (atomic_read(&kgdb_setting_breakpoint))
328 if (addr == (unsigned long)&kgdb_compiled_break)
329 return KGDB_COMPILED_BREAK;
330
331 return kgdb_has_hit_break(addr);
332}
333
334static int kgdb_riscv_notify(struct notifier_block *self, unsigned long cmd,
335 void *ptr)
336{
337 struct die_args *args = (struct die_args *)ptr;
338 struct pt_regs *regs = args->regs;
339 unsigned long flags;
340 int type;
341
342 if (user_mode(regs))
343 return NOTIFY_DONE;
344
345 type = kgdb_riscv_kgdbbreak(regs->epc);
346 if (type == NOT_KGDB_BREAK && cmd == DIE_TRAP)
347 return NOTIFY_DONE;
348
349 local_irq_save(flags);
350
351 if (kgdb_handle_exception(type == KGDB_SW_SINGLE_STEP ? 0 : 1,
352 args->signr, cmd, regs))
353 return NOTIFY_DONE;
354
355 if (type == KGDB_COMPILED_BREAK)
356 regs->epc += 4;
357
358 local_irq_restore(flags);
359
360 return NOTIFY_STOP;
361}
362
363static struct notifier_block kgdb_notifier = {
364 .notifier_call = kgdb_riscv_notify,
365};
366
367int kgdb_arch_init(void)
368{
369 register_die_notifier(&kgdb_notifier);
370
371 return 0;
372}
373
374void kgdb_arch_exit(void)
375{
376 unregister_die_notifier(&kgdb_notifier);
377}
378
379
380
381
382#ifdef CONFIG_RISCV_ISA_C
383const struct kgdb_arch arch_kgdb_ops = {
384 .gdb_bpt_instr = {0x02, 0x90},
385};
386#else
387const struct kgdb_arch arch_kgdb_ops = {
388 .gdb_bpt_instr = {0x73, 0x00, 0x10, 0x00},
389};
390#endif
391
