1 // SPDX-License-Identifier: GPL-2.0
2 /* kgdb.c: KGDB support for 32-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/sched.h>
10
11 #include <asm/kdebug.h>
12 #include <asm/ptrace.h>
13 #include <asm/irq.h>
14 #include <asm/cacheflush.h>
15
16 #include "kernel.h"
17 #include "entry.h"
18
19 void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
20 {
21 struct reg_window32 *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_window32 *) regs->u_regs[UREG_FP];
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_F31; i++)
35 gdb_regs[i] = 0;
36
37 gdb_regs[GDB_Y] = regs->y;
38 gdb_regs[GDB_PSR] = regs->psr;
39 gdb_regs[GDB_WIM] = 0;
40 gdb_regs[GDB_TBR] = (unsigned long) &trapbase[0];
41 gdb_regs[GDB_PC] = regs->pc;
42 gdb_regs[GDB_NPC] = regs->npc;
43 gdb_regs[GDB_FSR] = 0;
44 gdb_regs[GDB_CSR] = 0;
45 }
46
47 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
48 {
49 struct thread_info *t = task_thread_info(p);
50 struct reg_window32 *win;
51 int i;
52
53 for (i = GDB_G0; i < GDB_G6; i++)
54 gdb_regs[i] = 0;
55 gdb_regs[GDB_G6] = (unsigned long) t;
56 gdb_regs[GDB_G7] = 0;
57 for (i = GDB_O0; i < GDB_SP; i++)
58 gdb_regs[i] = 0;
59 gdb_regs[GDB_SP] = t->ksp;
60 gdb_regs[GDB_O7] = 0;
61
62 win = (struct reg_window32 *) t->ksp;
63 for (i = 0; i < 8; i++)
64 gdb_regs[GDB_L0 + i] = win->locals[i];
65 for (i = 0; i < 8; i++)
66 gdb_regs[GDB_I0 + i] = win->ins[i];
67
68 for (i = GDB_F0; i <= GDB_F31; i++)
69 gdb_regs[i] = 0;
70
71 gdb_regs[GDB_Y] = 0;
72
73 gdb_regs[GDB_PSR] = t->kpsr;
74 gdb_regs[GDB_WIM] = t->kwim;
75 gdb_regs[GDB_TBR] = (unsigned long) &trapbase[0];
76 gdb_regs[GDB_PC] = t->kpc;
77 gdb_regs[GDB_NPC] = t->kpc + 4;
78 gdb_regs[GDB_FSR] = 0;
79 gdb_regs[GDB_CSR] = 0;
80 }
81
82 void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
83 {
84 struct reg_window32 *win;
85 int i;
86
87 for (i = 0; i < 15; i++)
88 regs->u_regs[UREG_G1 + i] = gdb_regs[GDB_G1 + i];
89
90 /* If the PSR register is changing, we have to preserve
91 * the CWP field, otherwise window save/restore explodes.
92 */
93 if (regs->psr != gdb_regs[GDB_PSR]) {
94 unsigned long cwp = regs->psr & PSR_CWP;
95
96 regs->psr = (gdb_regs[GDB_PSR] & ~PSR_CWP) | cwp;
97 }
98
99 regs->pc = gdb_regs[GDB_PC];
100 regs->npc = gdb_regs[GDB_NPC];
101 regs->y = gdb_regs[GDB_Y];
102
103 win = (struct reg_window32 *) regs->u_regs[UREG_FP];
104 for (i = 0; i < 8; i++)
105 win->locals[i] = gdb_regs[GDB_L0 + i];
106 for (i = 0; i < 8; i++)
107 win->ins[i] = gdb_regs[GDB_I0 + i];
108 }
109
110 int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
111 char *remcomInBuffer, char *remcomOutBuffer,
112 struct pt_regs *linux_regs)
113 {
114 unsigned long addr;
115 char *ptr;
116
117 switch (remcomInBuffer[0]) {
118 case 'c':
119 /* try to read optional parameter, pc unchanged if no parm */
120 ptr = &remcomInBuffer[1];
121 if (kgdb_hex2long(&ptr, &addr)) {
122 linux_regs->pc = addr;
123 linux_regs->npc = addr + 4;
124 }
125 fallthrough;
126
127 case 'D':
128 case 'k':
129 if (linux_regs->pc == (unsigned long) arch_kgdb_breakpoint) {
130 linux_regs->pc = linux_regs->npc;
131 linux_regs->npc += 4;
132 }
133 return 0;
134 }
135 return -1;
136 }
137
138 asmlinkage void kgdb_trap(unsigned long trap_level, struct pt_regs *regs)
139 {
140 unsigned long flags;
141
142 if (user_mode(regs)) {
143 do_hw_interrupt(regs, trap_level);
144 return;
145 }
146
147 flushw_all();
148
149 local_irq_save(flags);
150 kgdb_handle_exception(trap_level, SIGTRAP, 0, regs);
151 local_irq_restore(flags);
152 }
153
154 int kgdb_arch_init(void)
155 {
156 return 0;
157 }
158
159 void kgdb_arch_exit(void)
160 {
161 }
162
163 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
164 {
165 regs->pc = ip;
166 regs->npc = regs->pc + 4;
167 }
168
169 const struct kgdb_arch arch_kgdb_ops = {
170 /* Breakpoint instruction: ta 0x7d */
171 .gdb_bpt_instr = { 0x91, 0xd0, 0x20, 0x7d },
172 };
173
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