1// SPDX-License-Identifier: GPL-2.0
2/*
3 * PA-RISC KGDB support
4 *
5 * Copyright (c) 2019 Sven Schnelle <svens@stackframe.org>
6 * Copyright (c) 2022 Helge Deller <deller@gmx.de>
7 *
8 */
9
10#include <linux/kgdb.h>
11#include <linux/string.h>
12#include <linux/sched.h>
13#include <linux/notifier.h>
14#include <linux/kdebug.h>
15#include <linux/uaccess.h>
16#include <asm/ptrace.h>
17#include <asm/traps.h>
18#include <asm/processor.h>
19#include <asm/patch.h>
20#include <asm/cacheflush.h>
21
22const struct kgdb_arch arch_kgdb_ops = {
23	.gdb_bpt_instr = { 0x03, 0xff, 0xa0, 0x1f }
24};
25
26static int __kgdb_notify(struct die_args *args, unsigned long cmd)
27{
28	struct pt_regs *regs = args->regs;
29
30	if (kgdb_handle_exception(1, args->signr, cmd, regs))
31		return NOTIFY_DONE;
32	return NOTIFY_STOP;
33}
34
35static int kgdb_notify(struct notifier_block *self,
36		       unsigned long cmd, void *ptr)
37{
38	unsigned long flags;
39	int ret;
40
41	local_irq_save(flags);
42	ret = __kgdb_notify(ptr, cmd);
43	local_irq_restore(flags);
44
45	return ret;
46}
47
48static struct notifier_block kgdb_notifier = {
49	.notifier_call	= kgdb_notify,
50	.priority	= -INT_MAX,
51};
52
53int kgdb_arch_init(void)
54{
55	return register_die_notifier(&kgdb_notifier);
56}
57
58void kgdb_arch_exit(void)
59{
60	unregister_die_notifier(&kgdb_notifier);
61}
62
63void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
64{
65	struct parisc_gdb_regs *gr = (struct parisc_gdb_regs *)gdb_regs;
66
67	memset(gr, 0, sizeof(struct parisc_gdb_regs));
68
69	memcpy(gr->gpr, regs->gr, sizeof(gr->gpr));
70	memcpy(gr->fr, regs->fr, sizeof(gr->fr));
71
72	gr->sr0 = regs->sr[0];
73	gr->sr1 = regs->sr[1];
74	gr->sr2 = regs->sr[2];
75	gr->sr3 = regs->sr[3];
76	gr->sr4 = regs->sr[4];
77	gr->sr5 = regs->sr[5];
78	gr->sr6 = regs->sr[6];
79	gr->sr7 = regs->sr[7];
80
81	gr->sar = regs->sar;
82	gr->iir = regs->iir;
83	gr->isr = regs->isr;
84	gr->ior = regs->ior;
85	gr->ipsw = regs->ipsw;
86	gr->cr27 = regs->cr27;
87
88	gr->iaoq_f = regs->iaoq[0];
89	gr->iasq_f = regs->iasq[0];
90
91	gr->iaoq_b = regs->iaoq[1];
92	gr->iasq_b = regs->iasq[1];
93}
94
95void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
96{
97	struct parisc_gdb_regs *gr = (struct parisc_gdb_regs *)gdb_regs;
98
99
100	memcpy(regs->gr, gr->gpr, sizeof(regs->gr));
101	memcpy(regs->fr, gr->fr, sizeof(regs->fr));
102
103	regs->sr[0] = gr->sr0;
104	regs->sr[1] = gr->sr1;
105	regs->sr[2] = gr->sr2;
106	regs->sr[3] = gr->sr3;
107	regs->sr[4] = gr->sr4;
108	regs->sr[5] = gr->sr5;
109	regs->sr[6] = gr->sr6;
110	regs->sr[7] = gr->sr7;
111
112	regs->sar = gr->sar;
113	regs->iir = gr->iir;
114	regs->isr = gr->isr;
115	regs->ior = gr->ior;
116	regs->ipsw = gr->ipsw;
117	regs->cr27 = gr->cr27;
118
119	regs->iaoq[0] = gr->iaoq_f;
120	regs->iasq[0] = gr->iasq_f;
121
122	regs->iaoq[1] = gr->iaoq_b;
123	regs->iasq[1] = gr->iasq_b;
124}
125
126void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs,
127				struct task_struct *task)
128{
129	struct pt_regs *regs = task_pt_regs(task);
130	unsigned long gr30, iaoq;
131
132	gr30 = regs->gr[30];
133	iaoq = regs->iaoq[0];
134
135	regs->gr[30] = regs->ksp;
136	regs->iaoq[0] = regs->kpc;
137	pt_regs_to_gdb_regs(gdb_regs, regs);
138
139	regs->gr[30] = gr30;
140	regs->iaoq[0] = iaoq;
141
142}
143
144static void step_instruction_queue(struct pt_regs *regs)
145{
146	regs->iaoq[0] = regs->iaoq[1];
147	regs->iaoq[1] += 4;
148}
149
150void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
151{
152	regs->iaoq[0] = ip;
153	regs->iaoq[1] = ip + 4;
154}
155
156int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
157{
158	int ret = copy_from_kernel_nofault(bpt->saved_instr,
159			(char *)bpt->bpt_addr, BREAK_INSTR_SIZE);
160	if (ret)
161		return ret;
162
163	__patch_text((void *)bpt->bpt_addr,
164			*(unsigned int *)&arch_kgdb_ops.gdb_bpt_instr);
165	return ret;
166}
167
168int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
169{
170	__patch_text((void *)bpt->bpt_addr, *(unsigned int *)&bpt->saved_instr);
171	return 0;
172}
173
174int kgdb_arch_handle_exception(int trap, int signo,
175		int err_code, char *inbuf, char *outbuf,
176		struct pt_regs *regs)
177{
178	unsigned long addr;
179	char *p = inbuf + 1;
180
181	switch (inbuf[0]) {
182	case 'D':
183	case 'c':
184	case 'k':
185		kgdb_contthread = NULL;
186		kgdb_single_step = 0;
187
188		if (kgdb_hex2long(&p, &addr))
189			kgdb_arch_set_pc(regs, addr);
190		else if (trap == 9 && regs->iir ==
191				PARISC_KGDB_COMPILED_BREAK_INSN)
192			step_instruction_queue(regs);
193		return 0;
194	case 's':
195		kgdb_single_step = 1;
196		if (kgdb_hex2long(&p, &addr)) {
197			kgdb_arch_set_pc(regs, addr);
198		} else if (trap == 9 && regs->iir ==
199				PARISC_KGDB_COMPILED_BREAK_INSN) {
200			step_instruction_queue(regs);
201			mtctl(-1, 0);
202		} else {
203			mtctl(0, 0);
204		}
205		regs->gr[0] |= PSW_R;
206		return 0;
207
208	}
209	return -1;
210}
211