1/* kgdb.c: KGDB support for 32-bit sparc.
2 *
3 * Copyright (C) 2008 David S. Miller <davem@davemloft.net>
4 */
5
6#include <linux/kgdb.h>
7#include <linux/kdebug.h>
8#include <linux/sched.h>
9
10#include <asm/kdebug.h>
11#include <asm/ptrace.h>
12#include <asm/irq.h>
13#include <asm/cacheflush.h>
14
15extern unsigned long trapbase;
16
17void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
18{
19	struct reg_window32 *win;
20	int i;
21
22	gdb_regs[GDB_G0] = 0;
23	for (i = 0; i < 15; i++)
24		gdb_regs[GDB_G1 + i] = regs->u_regs[UREG_G1 + i];
25
26	win = (struct reg_window32 *) regs->u_regs[UREG_FP];
27	for (i = 0; i < 8; i++)
28		gdb_regs[GDB_L0 + i] = win->locals[i];
29	for (i = 0; i < 8; i++)
30		gdb_regs[GDB_I0 + i] = win->ins[i];
31
32	for (i = GDB_F0; i <= GDB_F31; i++)
33		gdb_regs[i] = 0;
34
35	gdb_regs[GDB_Y] = regs->y;
36	gdb_regs[GDB_PSR] = regs->psr;
37	gdb_regs[GDB_WIM] = 0;
38	gdb_regs[GDB_TBR] = (unsigned long) &trapbase;
39	gdb_regs[GDB_PC] = regs->pc;
40	gdb_regs[GDB_NPC] = regs->npc;
41	gdb_regs[GDB_FSR] = 0;
42	gdb_regs[GDB_CSR] = 0;
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	struct reg_window32 *win;
49	int i;
50
51	for (i = GDB_G0; i < GDB_G6; i++)
52		gdb_regs[i] = 0;
53	gdb_regs[GDB_G6] = (unsigned long) t;
54	gdb_regs[GDB_G7] = 0;
55	for (i = GDB_O0; i < GDB_SP; i++)
56		gdb_regs[i] = 0;
57	gdb_regs[GDB_SP] = t->ksp;
58	gdb_regs[GDB_O7] = 0;
59
60	win = (struct reg_window32 *) t->ksp;
61	for (i = 0; i < 8; i++)
62		gdb_regs[GDB_L0 + i] = win->locals[i];
63	for (i = 0; i < 8; i++)
64		gdb_regs[GDB_I0 + i] = win->ins[i];
65
66	for (i = GDB_F0; i <= GDB_F31; i++)
67		gdb_regs[i] = 0;
68
69	gdb_regs[GDB_Y] = 0;
70
71	gdb_regs[GDB_PSR] = t->kpsr;
72	gdb_regs[GDB_WIM] = t->kwim;
73	gdb_regs[GDB_TBR] = (unsigned long) &trapbase;
74	gdb_regs[GDB_PC] = t->kpc;
75	gdb_regs[GDB_NPC] = t->kpc + 4;
76	gdb_regs[GDB_FSR] = 0;
77	gdb_regs[GDB_CSR] = 0;
78}
79
80void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
81{
82	struct reg_window32 *win;
83	int i;
84
85	for (i = 0; i < 15; i++)
86		regs->u_regs[UREG_G1 + i] = gdb_regs[GDB_G1 + i];
87
88	/* If the PSR register is changing, we have to preserve
89	 * the CWP field, otherwise window save/restore explodes.
90	 */
91	if (regs->psr != gdb_regs[GDB_PSR]) {
92		unsigned long cwp = regs->psr & PSR_CWP;
93
94		regs->psr = (gdb_regs[GDB_PSR] & ~PSR_CWP) | cwp;
95	}
96
97	regs->pc = gdb_regs[GDB_PC];
98	regs->npc = gdb_regs[GDB_NPC];
99	regs->y = gdb_regs[GDB_Y];
100
101	win = (struct reg_window32 *) regs->u_regs[UREG_FP];
102	for (i = 0; i < 8; i++)
103		win->locals[i] = gdb_regs[GDB_L0 + i];
104	for (i = 0; i < 8; i++)
105		win->ins[i] = gdb_regs[GDB_I0 + i];
106}
107
108int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
109			       char *remcomInBuffer, char *remcomOutBuffer,
110			       struct pt_regs *linux_regs)
111{
112	unsigned long addr;
113	char *ptr;
114
115	switch (remcomInBuffer[0]) {
116	case 'c':
117		/* try to read optional parameter, pc unchanged if no parm */
118		ptr = &remcomInBuffer[1];
119		if (kgdb_hex2long(&ptr, &addr)) {
120			linux_regs->pc = addr;
121			linux_regs->npc = addr + 4;
122		}
123		/* fallthru */
124
125	case 'D':
126	case 'k':
127		if (linux_regs->pc == (unsigned long) arch_kgdb_breakpoint) {
128			linux_regs->pc = linux_regs->npc;
129			linux_regs->npc += 4;
130		}
131		return 0;
132	}
133	return -1;
134}
135
136extern void do_hw_interrupt(struct pt_regs *regs, unsigned long type);
137
138asmlinkage void kgdb_trap(struct pt_regs *regs)
139{
140	unsigned long flags;
141
142	if (user_mode(regs)) {
143		do_hw_interrupt(regs, 0xfd);
144		return;
145	}
146
147	flushw_all();
148
149	local_irq_save(flags);
150	kgdb_handle_exception(0x172, 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
169struct kgdb_arch arch_kgdb_ops = {
170	/* Breakpoint instruction: ta 0x7d */
171	.gdb_bpt_instr		= { 0x91, 0xd0, 0x20, 0x7d },
172};
173