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 | |
22 | const struct kgdb_arch arch_kgdb_ops = { |
23 | .gdb_bpt_instr = { 0x03, 0xff, 0xa0, 0x1f } |
24 | }; |
25 | |
26 | static int __kgdb_notify(struct die_args *args, unsigned long cmd) |
27 | { |
28 | struct pt_regs *regs = args->regs; |
29 | |
30 | if (kgdb_handle_exception(ex_vector: 1, signo: args->signr, err_code: cmd, regs)) |
31 | return NOTIFY_DONE; |
32 | return NOTIFY_STOP; |
33 | } |
34 | |
35 | static 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(args: ptr, cmd); |
43 | local_irq_restore(flags); |
44 | |
45 | return ret; |
46 | } |
47 | |
48 | static struct notifier_block kgdb_notifier = { |
49 | .notifier_call = kgdb_notify, |
50 | .priority = -INT_MAX, |
51 | }; |
52 | |
53 | int kgdb_arch_init(void) |
54 | { |
55 | return register_die_notifier(nb: &kgdb_notifier); |
56 | } |
57 | |
58 | void kgdb_arch_exit(void) |
59 | { |
60 | unregister_die_notifier(nb: &kgdb_notifier); |
61 | } |
62 | |
63 | void 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 | |
95 | void 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 | |
126 | void 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 | |
144 | static void step_instruction_queue(struct pt_regs *regs) |
145 | { |
146 | regs->iaoq[0] = regs->iaoq[1]; |
147 | regs->iaoq[1] += 4; |
148 | } |
149 | |
150 | void 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 | |
156 | int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) |
157 | { |
158 | int ret = copy_from_kernel_nofault(dst: bpt->saved_instr, |
159 | src: (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 | |
168 | int 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 | |
174 | int 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(ptr: &p, long_val: &addr)) |
189 | kgdb_arch_set_pc(regs, ip: 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(ptr: &p, long_val: &addr)) { |
197 | kgdb_arch_set_pc(regs, ip: 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 | |