1 // SPDX-License-Identifier: GPL-2.0
2 /* kgdb.c: KGDB support for 64-bit sparc.
3 *
4 * Copyright (C) 2008 David S. Miller <davem@davemloft.net>
5 */
6
7 #include <linux/kgdb.h>
8 #include <linux/kdebug.h>
9 #include <linux/ftrace.h>
10 #include <linux/context_tracking.h>
11
12 #include <asm/cacheflush.h>
13 #include <asm/kdebug.h>
14 #include <asm/ptrace.h>
15 #include <asm/irq.h>
16
17 #include "kernel.h"
18
19 void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
20 {
21 struct reg_window *win;
22 int i;
23
24 gdb_regs[GDB_G0] = 0;
25 for (i = 0; i < 15; i++)
26 gdb_regs[GDB_G1 + i] = regs->u_regs[UREG_G1 + i];
27
28 win = (struct reg_window *) (regs->u_regs[UREG_FP] + STACK_BIAS);
29 for (i = 0; i < 8; i++)
30 gdb_regs[GDB_L0 + i] = win->locals[i];
31 for (i = 0; i < 8; i++)
32 gdb_regs[GDB_I0 + i] = win->ins[i];
33
34 for (i = GDB_F0; i <= GDB_F62; i++)
35 gdb_regs[i] = 0;
36
37 gdb_regs[GDB_PC] = regs->tpc;
38 gdb_regs[GDB_NPC] = regs->tnpc;
39 gdb_regs[GDB_STATE] = regs->tstate;
40 gdb_regs[GDB_FSR] = 0;
41 gdb_regs[GDB_FPRS] = 0;
42 gdb_regs[GDB_Y] = regs->y;
43 }
44
45 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
46 {
47 struct thread_info *t = task_thread_info(p);
48 extern unsigned int switch_to_pc;
49 extern unsigned int ret_from_fork;
50 struct reg_window *win;
51 unsigned long pc, cwp;
52 int i;
53
54 for (i = GDB_G0; i < GDB_G6; i++)
55 gdb_regs[i] = 0;
56 gdb_regs[GDB_G6] = (unsigned long) t;
57 gdb_regs[GDB_G7] = (unsigned long) p;
58 for (i = GDB_O0; i < GDB_SP; i++)
59 gdb_regs[i] = 0;
60 gdb_regs[GDB_SP] = t->ksp;
61 gdb_regs[GDB_O7] = 0;
62
63 win = (struct reg_window *) (t->ksp + STACK_BIAS);
64 for (i = 0; i < 8; i++)
65 gdb_regs[GDB_L0 + i] = win->locals[i];
66 for (i = 0; i < 8; i++)
67 gdb_regs[GDB_I0 + i] = win->ins[i];
68
69 for (i = GDB_F0; i <= GDB_F62; i++)
70 gdb_regs[i] = 0;
71
72 if (t->new_child)
73 pc = (unsigned long) &ret_from_fork;
74 else
75 pc = (unsigned long) &switch_to_pc;
76
77 gdb_regs[GDB_PC] = pc;
78 gdb_regs[GDB_NPC] = pc + 4;
79
80 cwp = __thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP];
81
82 gdb_regs[GDB_STATE] = (TSTATE_PRIV | TSTATE_IE | cwp);
83 gdb_regs[GDB_FSR] = 0;
84 gdb_regs[GDB_FPRS] = 0;
85 gdb_regs[GDB_Y] = 0;
86 }
87
88 void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
89 {
90 struct reg_window *win;
91 int i;
92
93 for (i = 0; i < 15; i++)
94 regs->u_regs[UREG_G1 + i] = gdb_regs[GDB_G1 + i];
95
96 /* If the TSTATE register is changing, we have to preserve
97 * the CWP field, otherwise window save/restore explodes.
98 */
99 if (regs->tstate != gdb_regs[GDB_STATE]) {
100 unsigned long cwp = regs->tstate & TSTATE_CWP;
101
102 regs->tstate = (gdb_regs[GDB_STATE] & ~TSTATE_CWP) | cwp;
103 }
104
105 regs->tpc = gdb_regs[GDB_PC];
106 regs->tnpc = gdb_regs[GDB_NPC];
107 regs->y = gdb_regs[GDB_Y];
108
109 win = (struct reg_window *) (regs->u_regs[UREG_FP] + STACK_BIAS);
110 for (i = 0; i < 8; i++)
111 win->locals[i] = gdb_regs[GDB_L0 + i];
112 for (i = 0; i < 8; i++)
113 win->ins[i] = gdb_regs[GDB_I0 + i];
114 }
115
116 #ifdef CONFIG_SMP
117 void __irq_entry smp_kgdb_capture_client(int irq, struct pt_regs *regs)
118 {
119 unsigned long flags;
120
121 __asm__ __volatile__("rdpr %%pstate, %0\n\t"
122 "wrpr %0, %1, %%pstate"
123 : "=r" (flags)
124 : "i" (PSTATE_IE));
125
126 flushw_all();
127
128 if (atomic_read(&kgdb_active) != -1)
129 kgdb_nmicallback(raw_smp_processor_id(), regs);
130
131 __asm__ __volatile__("wrpr %0, 0, %%pstate"
132 : : "r" (flags));
133 }
134 #endif
135
136 int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
137 char *remcomInBuffer, char *remcomOutBuffer,
138 struct pt_regs *linux_regs)
139 {
140 unsigned long addr;
141 char *ptr;
142
143 switch (remcomInBuffer[0]) {
144 case 'c':
145 /* try to read optional parameter, pc unchanged if no parm */
146 ptr = &remcomInBuffer[1];
147 if (kgdb_hex2long(&ptr, &addr)) {
148 linux_regs->tpc = addr;
149 linux_regs->tnpc = addr + 4;
150 }
151 fallthrough;
152
153 case 'D':
154 case 'k':
155 if (linux_regs->tpc == (unsigned long) arch_kgdb_breakpoint) {
156 linux_regs->tpc = linux_regs->tnpc;
157 linux_regs->tnpc += 4;
158 }
159 return 0;
160 }
161 return -1;
162 }
163
164 asmlinkage void kgdb_trap(unsigned long trap_level, struct pt_regs *regs)
165 {
166 enum ctx_state prev_state = exception_enter();
167 unsigned long flags;
168
169 if (user_mode(regs)) {
170 bad_trap(regs, trap_level);
171 goto out;
172 }
173
174 flushw_all();
175
176 local_irq_save(flags);
177 kgdb_handle_exception(0x172, SIGTRAP, 0, regs);
178 local_irq_restore(flags);
179 out:
180 exception_exit(prev_state);
181 }
182
183 int kgdb_arch_init(void)
184 {
185 return 0;
186 }
187
188 void kgdb_arch_exit(void)
189 {
190 }
191
192 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
193 {
194 regs->tpc = ip;
195 regs->tnpc = regs->tpc + 4;
196 }
197
198 const struct kgdb_arch arch_kgdb_ops = {
199 /* Breakpoint instruction: ta 0x72 */
200 .gdb_bpt_instr = { 0x91, 0xd0, 0x20, 0x72 },
201 };
202
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