1/* kgdb.c: KGDB support for 64-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/ftrace.h>
9#include <linux/context_tracking.h>
10
11#include <asm/cacheflush.h>
12#include <asm/kdebug.h>
13#include <asm/ptrace.h>
14#include <asm/irq.h>
15
16#include "kernel.h"
17
18void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
19{
20	struct reg_window *win;
21	int i;
22
23	gdb_regs[GDB_G0] = 0;
24	for (i = 0; i < 15; i++)
25		gdb_regs[GDB_G1 + i] = regs->u_regs[UREG_G1 + i];
26
27	win = (struct reg_window *) (regs->u_regs[UREG_FP] + STACK_BIAS);
28	for (i = 0; i < 8; i++)
29		gdb_regs[GDB_L0 + i] = win->locals[i];
30	for (i = 0; i < 8; i++)
31		gdb_regs[GDB_I0 + i] = win->ins[i];
32
33	for (i = GDB_F0; i <= GDB_F62; i++)
34		gdb_regs[i] = 0;
35
36	gdb_regs[GDB_PC] = regs->tpc;
37	gdb_regs[GDB_NPC] = regs->tnpc;
38	gdb_regs[GDB_STATE] = regs->tstate;
39	gdb_regs[GDB_FSR] = 0;
40	gdb_regs[GDB_FPRS] = 0;
41	gdb_regs[GDB_Y] = regs->y;
42}
43
44void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
45{
46	struct thread_info *t = task_thread_info(p);
47	extern unsigned int switch_to_pc;
48	extern unsigned int ret_from_fork;
49	struct reg_window *win;
50	unsigned long pc, cwp;
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] = (unsigned long) p;
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_window *) (t->ksp + STACK_BIAS);
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_F62; i++)
69		gdb_regs[i] = 0;
70
71	if (t->new_child)
72		pc = (unsigned long) &ret_from_fork;
73	else
74		pc = (unsigned long) &switch_to_pc;
75
76	gdb_regs[GDB_PC] = pc;
77	gdb_regs[GDB_NPC] = pc + 4;
78
79	cwp = __thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP];
80
81	gdb_regs[GDB_STATE] = (TSTATE_PRIV | TSTATE_IE | cwp);
82	gdb_regs[GDB_FSR] = 0;
83	gdb_regs[GDB_FPRS] = 0;
84	gdb_regs[GDB_Y] = 0;
85}
86
87void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
88{
89	struct reg_window *win;
90	int i;
91
92	for (i = 0; i < 15; i++)
93		regs->u_regs[UREG_G1 + i] = gdb_regs[GDB_G1 + i];
94
95	/* If the TSTATE register is changing, we have to preserve
96	 * the CWP field, otherwise window save/restore explodes.
97	 */
98	if (regs->tstate != gdb_regs[GDB_STATE]) {
99		unsigned long cwp = regs->tstate & TSTATE_CWP;
100
101		regs->tstate = (gdb_regs[GDB_STATE] & ~TSTATE_CWP) | cwp;
102	}
103
104	regs->tpc = gdb_regs[GDB_PC];
105	regs->tnpc = gdb_regs[GDB_NPC];
106	regs->y = gdb_regs[GDB_Y];
107
108	win = (struct reg_window *) (regs->u_regs[UREG_FP] + STACK_BIAS);
109	for (i = 0; i < 8; i++)
110		win->locals[i] = gdb_regs[GDB_L0 + i];
111	for (i = 0; i < 8; i++)
112		win->ins[i] = gdb_regs[GDB_I0 + i];
113}
114
115#ifdef CONFIG_SMP
116void __irq_entry smp_kgdb_capture_client(int irq, struct pt_regs *regs)
117{
118	unsigned long flags;
119
120	__asm__ __volatile__("rdpr      %%pstate, %0\n\t"
121			     "wrpr      %0, %1, %%pstate"
122			     : "=r" (flags)
123			     : "i" (PSTATE_IE));
124
125	flushw_all();
126
127	if (atomic_read(&kgdb_active) != -1)
128		kgdb_nmicallback(raw_smp_processor_id(), regs);
129
130	__asm__ __volatile__("wrpr	%0, 0, %%pstate"
131			     : : "r" (flags));
132}
133#endif
134
135int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
136			       char *remcomInBuffer, char *remcomOutBuffer,
137			       struct pt_regs *linux_regs)
138{
139	unsigned long addr;
140	char *ptr;
141
142	switch (remcomInBuffer[0]) {
143	case 'c':
144		/* try to read optional parameter, pc unchanged if no parm */
145		ptr = &remcomInBuffer[1];
146		if (kgdb_hex2long(&ptr, &addr)) {
147			linux_regs->tpc = addr;
148			linux_regs->tnpc = addr + 4;
149		}
150		/* fallthru */
151
152	case 'D':
153	case 'k':
154		if (linux_regs->tpc == (unsigned long) arch_kgdb_breakpoint) {
155			linux_regs->tpc = linux_regs->tnpc;
156			linux_regs->tnpc += 4;
157		}
158		return 0;
159	}
160	return -1;
161}
162
163asmlinkage void kgdb_trap(unsigned long trap_level, struct pt_regs *regs)
164{
165	enum ctx_state prev_state = exception_enter();
166	unsigned long flags;
167
168	if (user_mode(regs)) {
169		bad_trap(regs, trap_level);
170		goto out;
171	}
172
173	flushw_all();
174
175	local_irq_save(flags);
176	kgdb_handle_exception(0x172, SIGTRAP, 0, regs);
177	local_irq_restore(flags);
178out:
179	exception_exit(prev_state);
180}
181
182int kgdb_arch_init(void)
183{
184	return 0;
185}
186
187void kgdb_arch_exit(void)
188{
189}
190
191void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
192{
193	regs->tpc = ip;
194	regs->tnpc = regs->tpc + 4;
195}
196
197struct kgdb_arch arch_kgdb_ops = {
198	/* Breakpoint instruction: ta 0x72 */
199	.gdb_bpt_instr		= { 0x91, 0xd0, 0x20, 0x72 },
200};
201