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
19void 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
45void 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
88void 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
117void __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
136int 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
164asmlinkage 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);
179out:
180	exception_exit(prev_state);
181}
182
183int kgdb_arch_init(void)
184{
185	return 0;
186}
187
188void kgdb_arch_exit(void)
189{
190}
191
192void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
193{
194	regs->tpc = ip;
195	regs->tnpc = regs->tpc + 4;
196}
197
198const struct kgdb_arch arch_kgdb_ops = {
199	/* Breakpoint instruction: ta 0x72 */
200	.gdb_bpt_instr		= { 0x91, 0xd0, 0x20, 0x72 },
201};
202