kgdb.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * LoongArch KGDB support
  4 *
  5 * Copyright (C) 2023 Loongson Technology Corporation Limited
  6 */
  7
  8#include <linux/hw_breakpoint.h>
  9#include <linux/kdebug.h>
 10#include <linux/kgdb.h>
 11#include <linux/objtool.h>
 12#include <linux/processor.h>
 13#include <linux/ptrace.h>
 14#include <linux/sched.h>
 15#include <linux/smp.h>
 16
 17#include <asm/cacheflush.h>
 18#include <asm/fpu.h>
 19#include <asm/hw_breakpoint.h>
 20#include <asm/inst.h>
 21#include <asm/irq_regs.h>
 22#include <asm/ptrace.h>
 23#include <asm/sigcontext.h>
 24
 25int kgdb_watch_activated;
 26static unsigned int stepped_opcode;
 27static unsigned long stepped_address;
 28
 29struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = {
 30	{ "r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[0]) },
 31	{ "r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[1]) },
 32	{ "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[2]) },
 33	{ "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[3]) },
 34	{ "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[4]) },
 35	{ "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[5]) },
 36	{ "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[6]) },
 37	{ "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[7]) },
 38	{ "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[8]) },
 39	{ "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[9]) },
 40	{ "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[10]) },
 41	{ "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[11]) },
 42	{ "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[12]) },
 43	{ "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[13]) },
 44	{ "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[14]) },
 45	{ "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[15]) },
 46	{ "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[16]) },
 47	{ "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[17]) },
 48	{ "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[18]) },
 49	{ "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[19]) },
 50	{ "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[20]) },
 51	{ "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[21]) },
 52	{ "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[22]) },
 53	{ "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[23]) },
 54	{ "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[24]) },
 55	{ "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[25]) },
 56	{ "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[26]) },
 57	{ "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[27]) },
 58	{ "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[28]) },
 59	{ "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[29]) },
 60	{ "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[30]) },
 61	{ "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[31]) },
 62	{ "orig_a0", GDB_SIZEOF_REG, offsetof(struct pt_regs, orig_a0) },
 63	{ "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, csr_era) },
 64	{ "badv", GDB_SIZEOF_REG, offsetof(struct pt_regs, csr_badvaddr) },
 65	{ "f0", GDB_SIZEOF_REG, 0 },
 66	{ "f1", GDB_SIZEOF_REG, 1 },
 67	{ "f2", GDB_SIZEOF_REG, 2 },
 68	{ "f3", GDB_SIZEOF_REG, 3 },
 69	{ "f4", GDB_SIZEOF_REG, 4 },
 70	{ "f5", GDB_SIZEOF_REG, 5 },
 71	{ "f6", GDB_SIZEOF_REG, 6 },
 72	{ "f7", GDB_SIZEOF_REG, 7 },
 73	{ "f8", GDB_SIZEOF_REG, 8 },
 74	{ "f9", GDB_SIZEOF_REG, 9 },
 75	{ "f10", GDB_SIZEOF_REG, 10 },
 76	{ "f11", GDB_SIZEOF_REG, 11 },
 77	{ "f12", GDB_SIZEOF_REG, 12 },
 78	{ "f13", GDB_SIZEOF_REG, 13 },
 79	{ "f14", GDB_SIZEOF_REG, 14 },
 80	{ "f15", GDB_SIZEOF_REG, 15 },
 81	{ "f16", GDB_SIZEOF_REG, 16 },
 82	{ "f17", GDB_SIZEOF_REG, 17 },
 83	{ "f18", GDB_SIZEOF_REG, 18 },
 84	{ "f19", GDB_SIZEOF_REG, 19 },
 85	{ "f20", GDB_SIZEOF_REG, 20 },
 86	{ "f21", GDB_SIZEOF_REG, 21 },
 87	{ "f22", GDB_SIZEOF_REG, 22 },
 88	{ "f23", GDB_SIZEOF_REG, 23 },
 89	{ "f24", GDB_SIZEOF_REG, 24 },
 90	{ "f25", GDB_SIZEOF_REG, 25 },
 91	{ "f26", GDB_SIZEOF_REG, 26 },
 92	{ "f27", GDB_SIZEOF_REG, 27 },
 93	{ "f28", GDB_SIZEOF_REG, 28 },
 94	{ "f29", GDB_SIZEOF_REG, 29 },
 95	{ "f30", GDB_SIZEOF_REG, 30 },
 96	{ "f31", GDB_SIZEOF_REG, 31 },
 97	{ "fcc0", 1, 0 },
 98	{ "fcc1", 1, 1 },
 99	{ "fcc2", 1, 2 },
100	{ "fcc3", 1, 3 },
101	{ "fcc4", 1, 4 },
102	{ "fcc5", 1, 5 },
103	{ "fcc6", 1, 6 },
104	{ "fcc7", 1, 7 },
105	{ "fcsr", 4, 0 },
106};
107
108char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
109{
110	int reg_offset, reg_size;
111
112	if (regno < 0 || regno >= DBG_MAX_REG_NUM)
113		return NULL;
114
115	reg_offset = dbg_reg_def[regno].offset;
116	reg_size = dbg_reg_def[regno].size;
117
118	if (reg_offset == -1)
119		goto out;
120
121	/* Handle general-purpose/orig_a0/pc/badv registers */
122	if (regno <= DBG_PT_REGS_END) {
123		memcpy(mem, (void *)regs + reg_offset, reg_size);
124		goto out;
125	}
126
127	if (!(regs->csr_euen & CSR_EUEN_FPEN))
128		goto out;
129
130	save_fp(current);
131
132	/* Handle FP registers */
133	switch (regno) {
134	case DBG_FCSR:				/* Process the fcsr */
135		memcpy(mem, (void *)&current->thread.fpu.fcsr, reg_size);
136		break;
137	case DBG_FCC_BASE ... DBG_FCC_END:	/* Process the fcc */
138		memcpy(mem, (void *)&current->thread.fpu.fcc + reg_offset, reg_size);
139		break;
140	case DBG_FPR_BASE ... DBG_FPR_END:	/* Process the fpr */
141		memcpy(mem, (void *)&current->thread.fpu.fpr[reg_offset], reg_size);
142		break;
143	default:
144		break;
145	}
146
147out:
148	return dbg_reg_def[regno].name;
149}
150
151int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
152{
153	int reg_offset, reg_size;
154
155	if (regno < 0 || regno >= DBG_MAX_REG_NUM)
156		return -EINVAL;
157
158	reg_offset = dbg_reg_def[regno].offset;
159	reg_size = dbg_reg_def[regno].size;
160
161	if (reg_offset == -1)
162		return 0;
163
164	/* Handle general-purpose/orig_a0/pc/badv registers */
165	if (regno <= DBG_PT_REGS_END) {
166		memcpy((void *)regs + reg_offset, mem, reg_size);
167		return 0;
168	}
169
170	if (!(regs->csr_euen & CSR_EUEN_FPEN))
171		return 0;
172
173	/* Handle FP registers */
174	switch (regno) {
175	case DBG_FCSR:				/* Process the fcsr */
176		memcpy((void *)&current->thread.fpu.fcsr, mem, reg_size);
177		break;
178	case DBG_FCC_BASE ... DBG_FCC_END:	/* Process the fcc */
179		memcpy((void *)&current->thread.fpu.fcc + reg_offset, mem, reg_size);
180		break;
181	case DBG_FPR_BASE ... DBG_FPR_END:	/* Process the fpr */
182		memcpy((void *)&current->thread.fpu.fpr[reg_offset], mem, reg_size);
183		break;
184	default:
185		break;
186	}
187
188	restore_fp(current);
189
190	return 0;
191}
192
193/*
194 * Similar to regs_to_gdb_regs() except that process is sleeping and so
195 * we may not be able to get all the info.
196 */
197void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
198{
199	/* Initialize to zero */
200	memset((char *)gdb_regs, 0, NUMREGBYTES);
201
202	gdb_regs[DBG_LOONGARCH_RA] = p->thread.reg01;
203	gdb_regs[DBG_LOONGARCH_TP] = (long)p;
204	gdb_regs[DBG_LOONGARCH_SP] = p->thread.reg03;
205
206	/* S0 - S8 */
207	gdb_regs[DBG_LOONGARCH_S0] = p->thread.reg23;
208	gdb_regs[DBG_LOONGARCH_S1] = p->thread.reg24;
209	gdb_regs[DBG_LOONGARCH_S2] = p->thread.reg25;
210	gdb_regs[DBG_LOONGARCH_S3] = p->thread.reg26;
211	gdb_regs[DBG_LOONGARCH_S4] = p->thread.reg27;
212	gdb_regs[DBG_LOONGARCH_S5] = p->thread.reg28;
213	gdb_regs[DBG_LOONGARCH_S6] = p->thread.reg29;
214	gdb_regs[DBG_LOONGARCH_S7] = p->thread.reg30;
215	gdb_regs[DBG_LOONGARCH_S8] = p->thread.reg31;
216
217	/*
218	 * PC use return address (RA), i.e. the moment after return from __switch_to()
219	 */
220	gdb_regs[DBG_LOONGARCH_PC] = p->thread.reg01;
221}
222
223void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
224{
225	regs->csr_era = pc;
226}
227
228noinline void arch_kgdb_breakpoint(void)
229{
230	__asm__ __volatile__ (			\
231		".globl kgdb_breakinst\n\t"	\
232		"kgdb_breakinst:\tbreak 2\n\t"); /* BRK_KDB = 2 */
233}
234STACK_FRAME_NON_STANDARD(arch_kgdb_breakpoint);
235
236/*
237 * Calls linux_debug_hook before the kernel dies. If KGDB is enabled,
238 * then try to fall into the debugger
239 */
240static int kgdb_loongarch_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
241{
242	struct die_args *args = (struct die_args *)ptr;
243	struct pt_regs *regs = args->regs;
244
245	/* Userspace events, ignore. */
246	if (user_mode(regs))
247		return NOTIFY_DONE;
248
249	if (!kgdb_io_module_registered)
250		return NOTIFY_DONE;
251
252	if (atomic_read(&kgdb_active) != -1)
253		kgdb_nmicallback(smp_processor_id(), regs);
254
255	if (kgdb_handle_exception(args->trapnr, args->signr, cmd, regs))
256		return NOTIFY_DONE;
257
258	if (atomic_read(&kgdb_setting_breakpoint))
259		if (regs->csr_era == (unsigned long)&kgdb_breakinst)
260			regs->csr_era += LOONGARCH_INSN_SIZE;
261
262	return NOTIFY_STOP;
263}
264
265bool kgdb_breakpoint_handler(struct pt_regs *regs)
266{
267	struct die_args args = {
268		.regs	= regs,
269		.str	= "Break",
270		.err	= BRK_KDB,
271		.trapnr = read_csr_excode(),
272		.signr	= SIGTRAP,
273
274	};
275
276	return (kgdb_loongarch_notify(NULL, DIE_TRAP, &args) == NOTIFY_STOP) ? true : false;
277}
278
279static struct notifier_block kgdb_notifier = {
280	.notifier_call = kgdb_loongarch_notify,
281};
282
283static inline void kgdb_arch_update_addr(struct pt_regs *regs,
284					 char *remcom_in_buffer)
285{
286	unsigned long addr;
287	char *ptr;
288
289	ptr = &remcom_in_buffer[1];
290	if (kgdb_hex2long(&ptr, &addr))
291		regs->csr_era = addr;
292}
293
294/* Calculate the new address for after a step */
295static int get_step_address(struct pt_regs *regs, unsigned long *next_addr)
296{
297	char cj_val;
298	unsigned int si, si_l, si_h, rd, rj, cj;
299	unsigned long pc = instruction_pointer(regs);
300	union loongarch_instruction *ip = (union loongarch_instruction *)pc;
301
302	if (pc & 3) {
303		pr_warn("%s: invalid pc 0x%lx\n", __func__, pc);
304		return -EINVAL;
305	}
306
307	*next_addr = pc + LOONGARCH_INSN_SIZE;
308
309	si_h = ip->reg0i26_format.immediate_h;
310	si_l = ip->reg0i26_format.immediate_l;
311	switch (ip->reg0i26_format.opcode) {
312	case b_op:
313		*next_addr = pc + sign_extend64((si_h << 16 | si_l) << 2, 27);
314		return 0;
315	case bl_op:
316		*next_addr = pc + sign_extend64((si_h << 16 | si_l) << 2, 27);
317		regs->regs[1] = pc + LOONGARCH_INSN_SIZE;
318		return 0;
319	}
320
321	rj = ip->reg1i21_format.rj;
322	cj = (rj & 0x07) + DBG_FCC_BASE;
323	si_l = ip->reg1i21_format.immediate_l;
324	si_h = ip->reg1i21_format.immediate_h;
325	dbg_get_reg(cj, &cj_val, regs);
326	switch (ip->reg1i21_format.opcode) {
327	case beqz_op:
328		if (regs->regs[rj] == 0)
329			*next_addr = pc + sign_extend64((si_h << 16 | si_l) << 2, 22);
330		return 0;
331	case bnez_op:
332		if (regs->regs[rj] != 0)
333			*next_addr = pc + sign_extend64((si_h << 16 | si_l) << 2, 22);
334		return 0;
335	case bceqz_op: /* bceqz_op = bcnez_op */
336		if (((rj & 0x18) == 0x00) && !cj_val) /* bceqz */
337			*next_addr = pc + sign_extend64((si_h << 16 | si_l) << 2, 22);
338		if (((rj & 0x18) == 0x08) && cj_val) /* bcnez */
339			*next_addr = pc + sign_extend64((si_h << 16 | si_l) << 2, 22);
340		return 0;
341	}
342
343	rj = ip->reg2i16_format.rj;
344	rd = ip->reg2i16_format.rd;
345	si = ip->reg2i16_format.immediate;
346	switch (ip->reg2i16_format.opcode) {
347	case beq_op:
348		if (regs->regs[rj] == regs->regs[rd])
349			*next_addr = pc + sign_extend64(si << 2, 17);
350		return 0;
351	case bne_op:
352		if (regs->regs[rj] != regs->regs[rd])
353			*next_addr = pc + sign_extend64(si << 2, 17);
354		return 0;
355	case blt_op:
356		if ((long)regs->regs[rj] < (long)regs->regs[rd])
357			*next_addr = pc + sign_extend64(si << 2, 17);
358		return 0;
359	case bge_op:
360		if ((long)regs->regs[rj] >= (long)regs->regs[rd])
361			*next_addr = pc + sign_extend64(si << 2, 17);
362		return 0;
363	case bltu_op:
364		if (regs->regs[rj] < regs->regs[rd])
365			*next_addr = pc + sign_extend64(si << 2, 17);
366		return 0;
367	case bgeu_op:
368		if (regs->regs[rj] >= regs->regs[rd])
369			*next_addr = pc + sign_extend64(si << 2, 17);
370		return 0;
371	case jirl_op:
372		regs->regs[rd] = pc + LOONGARCH_INSN_SIZE;
373		*next_addr = regs->regs[rj] + sign_extend64(si << 2, 17);
374		return 0;
375	}
376
377	return 0;
378}
379
380static int do_single_step(struct pt_regs *regs)
381{
382	int error = 0;
383	unsigned long addr = 0; /* Determine where the target instruction will send us to */
384
385	error = get_step_address(regs, &addr);
386	if (error)
387		return error;
388
389	/* Store the opcode in the stepped address */
390	error = get_kernel_nofault(stepped_opcode, (void *)addr);
391	if (error)
392		return error;
393
394	stepped_address = addr;
395
396	/* Replace the opcode with the break instruction */
397	error = copy_to_kernel_nofault((void *)stepped_address,
398				       arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE);
399	flush_icache_range(addr, addr + BREAK_INSTR_SIZE);
400
401	if (error) {
402		stepped_opcode = 0;
403		stepped_address = 0;
404	} else {
405		kgdb_single_step = 1;
406		atomic_set(&kgdb_cpu_doing_single_step, raw_smp_processor_id());
407	}
408
409	return error;
410}
411
412/* Undo a single step */
413static void undo_single_step(struct pt_regs *regs)
414{
415	if (stepped_opcode) {
416		copy_to_kernel_nofault((void *)stepped_address,
417				       (void *)&stepped_opcode, BREAK_INSTR_SIZE);
418		flush_icache_range(stepped_address, stepped_address + BREAK_INSTR_SIZE);
419	}
420
421	stepped_opcode = 0;
422	stepped_address = 0;
423	kgdb_single_step = 0;
424	atomic_set(&kgdb_cpu_doing_single_step, -1);
425}
426
427int kgdb_arch_handle_exception(int vector, int signo, int err_code,
428			       char *remcom_in_buffer, char *remcom_out_buffer,
429			       struct pt_regs *regs)
430{
431	int ret = 0;
432
433	undo_single_step(regs);
434	regs->csr_prmd |= CSR_PRMD_PWE;
435
436	switch (remcom_in_buffer[0]) {
437	case 'D':
438	case 'k':
439		regs->csr_prmd &= ~CSR_PRMD_PWE;
440		fallthrough;
441	case 'c':
442		kgdb_arch_update_addr(regs, remcom_in_buffer);
443		break;
444	case 's':
445		kgdb_arch_update_addr(regs, remcom_in_buffer);
446		ret = do_single_step(regs);
447		break;
448	default:
449		ret = -1;
450	}
451
452	return ret;
453}
454
455static struct hw_breakpoint {
456	unsigned int		enabled;
457	unsigned long		addr;
458	int			len;
459	int			type;
460	struct perf_event	* __percpu *pev;
461} breakinfo[LOONGARCH_MAX_BRP];
462
463static int hw_break_reserve_slot(int breakno)
464{
465	int cpu, cnt = 0;
466	struct perf_event **pevent;
467
468	for_each_online_cpu(cpu) {
469		cnt++;
470		pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
471		if (dbg_reserve_bp_slot(*pevent))
472			goto fail;
473	}
474
475	return 0;
476
477fail:
478	for_each_online_cpu(cpu) {
479		cnt--;
480		if (!cnt)
481			break;
482		pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
483		dbg_release_bp_slot(*pevent);
484	}
485
486	return -1;
487}
488
489static int hw_break_release_slot(int breakno)
490{
491	int cpu;
492	struct perf_event **pevent;
493
494	if (dbg_is_early)
495		return 0;
496
497	for_each_online_cpu(cpu) {
498		pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
499		if (dbg_release_bp_slot(*pevent))
500			/*
501			 * The debugger is responsible for handing the retry on
502			 * remove failure.
503			 */
504			return -1;
505	}
506
507	return 0;
508}
509
510static int kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
511{
512	int i;
513
514	for (i = 0; i < LOONGARCH_MAX_BRP; i++)
515		if (!breakinfo[i].enabled)
516			break;
517
518	if (i == LOONGARCH_MAX_BRP)
519		return -1;
520
521	switch (bptype) {
522	case BP_HARDWARE_BREAKPOINT:
523		breakinfo[i].type = HW_BREAKPOINT_X;
524		break;
525	case BP_READ_WATCHPOINT:
526		breakinfo[i].type = HW_BREAKPOINT_R;
527		break;
528	case BP_WRITE_WATCHPOINT:
529		breakinfo[i].type = HW_BREAKPOINT_W;
530		break;
531	case BP_ACCESS_WATCHPOINT:
532		breakinfo[i].type = HW_BREAKPOINT_RW;
533		break;
534	default:
535		return -1;
536	}
537
538	switch (len) {
539	case 1:
540		breakinfo[i].len = HW_BREAKPOINT_LEN_1;
541		break;
542	case 2:
543		breakinfo[i].len = HW_BREAKPOINT_LEN_2;
544		break;
545	case 4:
546		breakinfo[i].len = HW_BREAKPOINT_LEN_4;
547		break;
548	case 8:
549		breakinfo[i].len = HW_BREAKPOINT_LEN_8;
550		break;
551	default:
552		return -1;
553	}
554
555	breakinfo[i].addr = addr;
556	if (hw_break_reserve_slot(i)) {
557		breakinfo[i].addr = 0;
558		return -1;
559	}
560	breakinfo[i].enabled = 1;
561
562	return 0;
563}
564
565static int kgdb_remove_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
566{
567	int i;
568
569	for (i = 0; i < LOONGARCH_MAX_BRP; i++)
570		if (breakinfo[i].addr == addr && breakinfo[i].enabled)
571			break;
572
573	if (i == LOONGARCH_MAX_BRP)
574		return -1;
575
576	if (hw_break_release_slot(i)) {
577		pr_err("Cannot remove hw breakpoint at %lx\n", addr);
578		return -1;
579	}
580	breakinfo[i].enabled = 0;
581
582	return 0;
583}
584
585static void kgdb_disable_hw_break(struct pt_regs *regs)
586{
587	int i;
588	int cpu = raw_smp_processor_id();
589	struct perf_event *bp;
590
591	for (i = 0; i < LOONGARCH_MAX_BRP; i++) {
592		if (!breakinfo[i].enabled)
593			continue;
594
595		bp = *per_cpu_ptr(breakinfo[i].pev, cpu);
596		if (bp->attr.disabled == 1)
597			continue;
598
599		arch_uninstall_hw_breakpoint(bp);
600		bp->attr.disabled = 1;
601	}
602
603	/* Disable hardware debugging while we are in kgdb */
604	csr_xchg32(0, CSR_CRMD_WE, LOONGARCH_CSR_CRMD);
605}
606
607static void kgdb_remove_all_hw_break(void)
608{
609	int i;
610	int cpu = raw_smp_processor_id();
611	struct perf_event *bp;
612
613	for (i = 0; i < LOONGARCH_MAX_BRP; i++) {
614		if (!breakinfo[i].enabled)
615			continue;
616
617		bp = *per_cpu_ptr(breakinfo[i].pev, cpu);
618		if (!bp->attr.disabled) {
619			arch_uninstall_hw_breakpoint(bp);
620			bp->attr.disabled = 1;
621			continue;
622		}
623
624		if (hw_break_release_slot(i))
625			pr_err("KGDB: hw bpt remove failed %lx\n", breakinfo[i].addr);
626		breakinfo[i].enabled = 0;
627	}
628
629	csr_xchg32(0, CSR_CRMD_WE, LOONGARCH_CSR_CRMD);
630	kgdb_watch_activated = 0;
631}
632
633static void kgdb_correct_hw_break(void)
634{
635	int i, activated = 0;
636
637	for (i = 0; i < LOONGARCH_MAX_BRP; i++) {
638		struct perf_event *bp;
639		int val;
640		int cpu = raw_smp_processor_id();
641
642		if (!breakinfo[i].enabled)
643			continue;
644
645		bp = *per_cpu_ptr(breakinfo[i].pev, cpu);
646		if (bp->attr.disabled != 1)
647			continue;
648
649		bp->attr.bp_addr = breakinfo[i].addr;
650		bp->attr.bp_len = breakinfo[i].len;
651		bp->attr.bp_type = breakinfo[i].type;
652
653		val = hw_breakpoint_arch_parse(bp, &bp->attr, counter_arch_bp(bp));
654		if (val)
655			return;
656
657		val = arch_install_hw_breakpoint(bp);
658		if (!val)
659			bp->attr.disabled = 0;
660		activated = 1;
661	}
662
663	csr_xchg32(activated ? CSR_CRMD_WE : 0, CSR_CRMD_WE, LOONGARCH_CSR_CRMD);
664	kgdb_watch_activated = activated;
665}
666
667const struct kgdb_arch arch_kgdb_ops = {
668	.gdb_bpt_instr		= {0x02, 0x00, break_op >> 1, 0x00}, /* BRK_KDB = 2 */
669	.flags			= KGDB_HW_BREAKPOINT,
670	.set_hw_breakpoint	= kgdb_set_hw_break,
671	.remove_hw_breakpoint	= kgdb_remove_hw_break,
672	.disable_hw_break	= kgdb_disable_hw_break,
673	.remove_all_hw_break	= kgdb_remove_all_hw_break,
674	.correct_hw_break	= kgdb_correct_hw_break,
675};
676
677int kgdb_arch_init(void)
678{
679	return register_die_notifier(&kgdb_notifier);
680}
681
682void kgdb_arch_late(void)
683{
684	int i, cpu;
685	struct perf_event_attr attr;
686	struct perf_event **pevent;
687
688	hw_breakpoint_init(&attr);
689
690	attr.bp_addr = (unsigned long)kgdb_arch_init;
691	attr.bp_len = HW_BREAKPOINT_LEN_4;
692	attr.bp_type = HW_BREAKPOINT_W;
693	attr.disabled = 1;
694
695	for (i = 0; i < LOONGARCH_MAX_BRP; i++) {
696		if (breakinfo[i].pev)
697			continue;
698
699		breakinfo[i].pev = register_wide_hw_breakpoint(&attr, NULL, NULL);
700		if (IS_ERR((void * __force)breakinfo[i].pev)) {
701			pr_err("kgdb: Could not allocate hw breakpoints.\n");
702			breakinfo[i].pev = NULL;
703			return;
704		}
705
706		for_each_online_cpu(cpu) {
707			pevent = per_cpu_ptr(breakinfo[i].pev, cpu);
708			if (pevent[0]->destroy) {
709				pevent[0]->destroy = NULL;
710				release_bp_slot(*pevent);
711			}
712		}
713	}
714}
715
716void kgdb_arch_exit(void)
717{
718	int i;
719
720	for (i = 0; i < LOONGARCH_MAX_BRP; i++) {
721		if (breakinfo[i].pev) {
722			unregister_wide_hw_breakpoint(breakinfo[i].pev);
723			breakinfo[i].pev = NULL;
724		}
725	}
726
727	unregister_die_notifier(&kgdb_notifier);
728}