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