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
19void 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
47void 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
82void 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
110int 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
138asmlinkage 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
154int kgdb_arch_init(void)
155{
156	return 0;
157}
158
159void kgdb_arch_exit(void)
160{
161}
162
163void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
164{
165	regs->pc = ip;
166	regs->npc = regs->pc + 4;
167}
168
169const struct kgdb_arch arch_kgdb_ops = {
170	/* Breakpoint instruction: ta 0x7d */
171	.gdb_bpt_instr		= { 0x91, 0xd0, 0x20, 0x7d },
172};
173