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
 10#include <asm/kdebug.h>
 11#include <asm/ptrace.h>
 12#include <asm/irq.h>
 13
 14void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
 15{
 16	struct reg_window *win;
 17	int i;
 18
 19	gdb_regs[GDB_G0] = 0;
 20	for (i = 0; i < 15; i++)
 21		gdb_regs[GDB_G1 + i] = regs->u_regs[UREG_G1 + i];
 22
 23	win = (struct reg_window *) (regs->u_regs[UREG_FP] + STACK_BIAS);
 24	for (i = 0; i < 8; i++)
 25		gdb_regs[GDB_L0 + i] = win->locals[i];
 26	for (i = 0; i < 8; i++)
 27		gdb_regs[GDB_I0 + i] = win->ins[i];
 28
 29	for (i = GDB_F0; i <= GDB_F62; i++)
 30		gdb_regs[i] = 0;
 31
 32	gdb_regs[GDB_PC] = regs->tpc;
 33	gdb_regs[GDB_NPC] = regs->tnpc;
 34	gdb_regs[GDB_STATE] = regs->tstate;
 35	gdb_regs[GDB_FSR] = 0;
 36	gdb_regs[GDB_FPRS] = 0;
 37	gdb_regs[GDB_Y] = regs->y;
 38}
 39
 40void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
 41{
 42	struct thread_info *t = task_thread_info(p);
 43	extern unsigned int switch_to_pc;
 44	extern unsigned int ret_from_syscall;
 45	struct reg_window *win;
 46	unsigned long pc, cwp;
 47	int i;
 48
 49	for (i = GDB_G0; i < GDB_G6; i++)
 50		gdb_regs[i] = 0;
 51	gdb_regs[GDB_G6] = (unsigned long) t;
 52	gdb_regs[GDB_G7] = (unsigned long) p;
 53	for (i = GDB_O0; i < GDB_SP; i++)
 54		gdb_regs[i] = 0;
 55	gdb_regs[GDB_SP] = t->ksp;
 56	gdb_regs[GDB_O7] = 0;
 57
 58	win = (struct reg_window *) (t->ksp + STACK_BIAS);
 59	for (i = 0; i < 8; i++)
 60		gdb_regs[GDB_L0 + i] = win->locals[i];
 61	for (i = 0; i < 8; i++)
 62		gdb_regs[GDB_I0 + i] = win->ins[i];
 63
 64	for (i = GDB_F0; i <= GDB_F62; i++)
 65		gdb_regs[i] = 0;
 66
 67	if (t->new_child)
 68		pc = (unsigned long) &ret_from_syscall;
 69	else
 70		pc = (unsigned long) &switch_to_pc;
 71
 72	gdb_regs[GDB_PC] = pc;
 73	gdb_regs[GDB_NPC] = pc + 4;
 74
 75	cwp = __thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP];
 76
 77	gdb_regs[GDB_STATE] = (TSTATE_PRIV | TSTATE_IE | cwp);
 78	gdb_regs[GDB_FSR] = 0;
 79	gdb_regs[GDB_FPRS] = 0;
 80	gdb_regs[GDB_Y] = 0;
 81}
 82
 83void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
 84{
 85	struct reg_window *win;
 86	int i;
 87
 88	for (i = 0; i < 15; i++)
 89		regs->u_regs[UREG_G1 + i] = gdb_regs[GDB_G1 + i];
 90
 91	/* If the TSTATE register is changing, we have to preserve
 92	 * the CWP field, otherwise window save/restore explodes.
 93	 */
 94	if (regs->tstate != gdb_regs[GDB_STATE]) {
 95		unsigned long cwp = regs->tstate & TSTATE_CWP;
 96
 97		regs->tstate = (gdb_regs[GDB_STATE] & ~TSTATE_CWP) | cwp;
 98	}
 99
100	regs->tpc = gdb_regs[GDB_PC];
101	regs->tnpc = gdb_regs[GDB_NPC];
102	regs->y = gdb_regs[GDB_Y];
103
104	win = (struct reg_window *) (regs->u_regs[UREG_FP] + STACK_BIAS);
105	for (i = 0; i < 8; i++)
106		win->locals[i] = gdb_regs[GDB_L0 + i];
107	for (i = 0; i < 8; i++)
108		win->ins[i] = gdb_regs[GDB_I0 + i];
109}
110
111#ifdef CONFIG_SMP
112void __irq_entry smp_kgdb_capture_client(int irq, struct pt_regs *regs)
113{
114	unsigned long flags;
115
116	__asm__ __volatile__("rdpr      %%pstate, %0\n\t"
117			     "wrpr      %0, %1, %%pstate"
118			     : "=r" (flags)
119			     : "i" (PSTATE_IE));
120
121	flushw_all();
122
123	if (atomic_read(&kgdb_active) != -1)
124		kgdb_nmicallback(raw_smp_processor_id(), regs);
125
126	__asm__ __volatile__("wrpr	%0, 0, %%pstate"
127			     : : "r" (flags));
128}
129#endif
130
131int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
132			       char *remcomInBuffer, char *remcomOutBuffer,
133			       struct pt_regs *linux_regs)
134{
135	unsigned long addr;
136	char *ptr;
137
138	switch (remcomInBuffer[0]) {
139	case 'c':
140		/* try to read optional parameter, pc unchanged if no parm */
141		ptr = &remcomInBuffer[1];
142		if (kgdb_hex2long(&ptr, &addr)) {
143			linux_regs->tpc = addr;
144			linux_regs->tnpc = addr + 4;
145		}
146		/* fallthru */
147
148	case 'D':
149	case 'k':
150		if (linux_regs->tpc == (unsigned long) arch_kgdb_breakpoint) {
151			linux_regs->tpc = linux_regs->tnpc;
152			linux_regs->tnpc += 4;
153		}
154		return 0;
155	}
156	return -1;
157}
158
159asmlinkage void kgdb_trap(unsigned long trap_level, struct pt_regs *regs)
160{
161	unsigned long flags;
162
163	if (user_mode(regs)) {
164		bad_trap(regs, trap_level);
165		return;
166	}
167
168	flushw_all();
169
170	local_irq_save(flags);
171	kgdb_handle_exception(0x172, SIGTRAP, 0, regs);
172	local_irq_restore(flags);
173}
174
175int kgdb_arch_init(void)
176{
177	return 0;
178}
179
180void kgdb_arch_exit(void)
181{
182}
183
184void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
185{
186	regs->tpc = ip;
187	regs->tnpc = regs->tpc + 4;
188}
189
190struct kgdb_arch arch_kgdb_ops = {
191	/* Breakpoint instruction: ta 0x72 */
192	.gdb_bpt_instr		= { 0x91, 0xd0, 0x20, 0x72 },
193};