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: &ptr, long_val: &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(ex_vector: 0x172, SIGTRAP, err_code: 0, regs); |
178 | local_irq_restore(flags); |
179 | out: |
180 | exception_exit(prev_ctx: 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 | |