1/*
2 * arch/score/kernel/ptrace.c
3 *
4 * Score Processor version.
5 *
6 * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
7 *  Chen Liqin <liqin.chen@sunplusct.com>
8 *  Lennox Wu <lennox.wu@sunplusct.com>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, see the file COPYING, or write
22 * to the Free Software Foundation, Inc.,
23 * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
24 */
25
26#include <linux/elf.h>
27#include <linux/kernel.h>
28#include <linux/mm.h>
29#include <linux/ptrace.h>
30#include <linux/regset.h>
31
32#include <asm/uaccess.h>
33
34/*
35 * retrieve the contents of SCORE userspace general registers
36 */
37static int genregs_get(struct task_struct *target,
38		       const struct user_regset *regset,
39		       unsigned int pos, unsigned int count,
40		       void *kbuf, void __user *ubuf)
41{
42	const struct pt_regs *regs = task_pt_regs(target);
43	int ret;
44
45	/* skip 9 * sizeof(unsigned long) not use for pt_regs */
46	ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
47					0, offsetof(struct pt_regs, regs));
48
49	/* r0 - r31, cel, ceh, sr0, sr1, sr2, epc, ema, psr, ecr, condition */
50	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
51				  regs->regs,
52				  offsetof(struct pt_regs, regs),
53				  offsetof(struct pt_regs, cp0_condition));
54
55	if (!ret)
56		ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
57						sizeof(struct pt_regs), -1);
58
59	return ret;
60}
61
62/*
63 * update the contents of the SCORE userspace general registers
64 */
65static int genregs_set(struct task_struct *target,
66		       const struct user_regset *regset,
67		       unsigned int pos, unsigned int count,
68		       const void *kbuf, const void __user *ubuf)
69{
70	struct pt_regs *regs = task_pt_regs(target);
71	int ret;
72
73	/* skip 9 * sizeof(unsigned long) */
74	ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
75					0, offsetof(struct pt_regs, regs));
76
77	/* r0 - r31, cel, ceh, sr0, sr1, sr2, epc, ema, psr, ecr, condition */
78	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
79				  regs->regs,
80				  offsetof(struct pt_regs, regs),
81				  offsetof(struct pt_regs, cp0_condition));
82
83	if (!ret)
84		ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
85						sizeof(struct pt_regs), -1);
86
87	return ret;
88}
89
90/*
91 * Define the register sets available on the score7 under Linux
92 */
93enum score7_regset {
94	REGSET_GENERAL,
95};
96
97static const struct user_regset score7_regsets[] = {
98	[REGSET_GENERAL] = {
99		.core_note_type	= NT_PRSTATUS,
100		.n		= ELF_NGREG,
101		.size		= sizeof(long),
102		.align		= sizeof(long),
103		.get		= genregs_get,
104		.set		= genregs_set,
105	},
106};
107
108static const struct user_regset_view user_score_native_view = {
109	.name		= "score7",
110	.e_machine	= EM_SCORE7,
111	.regsets	= score7_regsets,
112	.n		= ARRAY_SIZE(score7_regsets),
113};
114
115const struct user_regset_view *task_user_regset_view(struct task_struct *task)
116{
117	return &user_score_native_view;
118}
119
120static int is_16bitinsn(unsigned long insn)
121{
122	if ((insn & INSN32_MASK) == INSN32_MASK)
123		return 0;
124	else
125		return 1;
126}
127
128int
129read_tsk_long(struct task_struct *child,
130		unsigned long addr, unsigned long *res)
131{
132	int copied;
133
134	copied = access_process_vm(child, addr, res, sizeof(*res), 0);
135
136	return copied != sizeof(*res) ? -EIO : 0;
137}
138
139int
140read_tsk_short(struct task_struct *child,
141		unsigned long addr, unsigned short *res)
142{
143	int copied;
144
145	copied = access_process_vm(child, addr, res, sizeof(*res), 0);
146
147	return copied != sizeof(*res) ? -EIO : 0;
148}
149
150static int
151write_tsk_short(struct task_struct *child,
152		unsigned long addr, unsigned short val)
153{
154	int copied;
155
156	copied = access_process_vm(child, addr, &val, sizeof(val), 1);
157
158	return copied != sizeof(val) ? -EIO : 0;
159}
160
161static int
162write_tsk_long(struct task_struct *child,
163		unsigned long addr, unsigned long val)
164{
165	int copied;
166
167	copied = access_process_vm(child, addr, &val, sizeof(val), 1);
168
169	return copied != sizeof(val) ? -EIO : 0;
170}
171
172void user_enable_single_step(struct task_struct *child)
173{
174	/* far_epc is the target of branch */
175	unsigned int epc, far_epc = 0;
176	unsigned long epc_insn, far_epc_insn;
177	int ninsn_type;			/* next insn type 0=16b, 1=32b */
178	unsigned int tmp, tmp2;
179	struct pt_regs *regs = task_pt_regs(child);
180	child->thread.single_step = 1;
181	child->thread.ss_nextcnt = 1;
182	epc = regs->cp0_epc;
183
184	read_tsk_long(child, epc, &epc_insn);
185
186	if (is_16bitinsn(epc_insn)) {
187		if ((epc_insn & J16M) == J16) {
188			tmp = epc_insn & 0xFFE;
189			epc = (epc & 0xFFFFF000) | tmp;
190		} else if ((epc_insn & B16M) == B16) {
191			child->thread.ss_nextcnt = 2;
192			tmp = (epc_insn & 0xFF) << 1;
193			tmp = tmp << 23;
194			tmp = (unsigned int)((int) tmp >> 23);
195			far_epc = epc + tmp;
196			epc += 2;
197		} else if ((epc_insn & BR16M) == BR16) {
198			child->thread.ss_nextcnt = 2;
199			tmp = (epc_insn >> 4) & 0xF;
200			far_epc = regs->regs[tmp];
201			epc += 2;
202		} else
203			epc += 2;
204	} else {
205		if ((epc_insn & J32M) == J32) {
206			tmp = epc_insn & 0x03FFFFFE;
207			tmp2 = tmp & 0x7FFF;
208			tmp = (((tmp >> 16) & 0x3FF) << 15) | tmp2;
209			epc = (epc & 0xFFC00000) | tmp;
210		} else if ((epc_insn & B32M) == B32) {
211			child->thread.ss_nextcnt = 2;
212			tmp = epc_insn & 0x03FFFFFE;	/* discard LK bit */
213			tmp2 = tmp & 0x3FF;
214			tmp = (((tmp >> 16) & 0x3FF) << 10) | tmp2; /* 20bit */
215			tmp = tmp << 12;
216			tmp = (unsigned int)((int) tmp >> 12);
217			far_epc = epc + tmp;
218			epc += 4;
219		} else if ((epc_insn & BR32M) == BR32) {
220			child->thread.ss_nextcnt = 2;
221			tmp = (epc_insn >> 16) & 0x1F;
222			far_epc = regs->regs[tmp];
223			epc += 4;
224		} else
225			epc += 4;
226	}
227
228	if (child->thread.ss_nextcnt == 1) {
229		read_tsk_long(child, epc, &epc_insn);
230
231		if (is_16bitinsn(epc_insn)) {
232			write_tsk_short(child, epc, SINGLESTEP16_INSN);
233			ninsn_type = 0;
234		} else {
235			write_tsk_long(child, epc, SINGLESTEP32_INSN);
236			ninsn_type = 1;
237		}
238
239		if (ninsn_type == 0) {  /* 16bits */
240			child->thread.insn1_type = 0;
241			child->thread.addr1 = epc;
242			 /* the insn may have 32bit data */
243			child->thread.insn1 = (short)epc_insn;
244		} else {
245			child->thread.insn1_type = 1;
246			child->thread.addr1 = epc;
247			child->thread.insn1 = epc_insn;
248		}
249	} else {
250		/* branch! have two target child->thread.ss_nextcnt=2 */
251		read_tsk_long(child, epc, &epc_insn);
252		read_tsk_long(child, far_epc, &far_epc_insn);
253		if (is_16bitinsn(epc_insn)) {
254			write_tsk_short(child, epc, SINGLESTEP16_INSN);
255			ninsn_type = 0;
256		} else {
257			write_tsk_long(child, epc, SINGLESTEP32_INSN);
258			ninsn_type = 1;
259		}
260
261		if (ninsn_type == 0) {  /* 16bits */
262			child->thread.insn1_type = 0;
263			child->thread.addr1 = epc;
264			 /* the insn may have 32bit data */
265			child->thread.insn1 = (short)epc_insn;
266		} else {
267			child->thread.insn1_type = 1;
268			child->thread.addr1 = epc;
269			child->thread.insn1 = epc_insn;
270		}
271
272		if (is_16bitinsn(far_epc_insn)) {
273			write_tsk_short(child, far_epc, SINGLESTEP16_INSN);
274			ninsn_type = 0;
275		} else {
276			write_tsk_long(child, far_epc, SINGLESTEP32_INSN);
277			ninsn_type = 1;
278		}
279
280		if (ninsn_type == 0) {  /* 16bits */
281			child->thread.insn2_type = 0;
282			child->thread.addr2 = far_epc;
283			 /* the insn may have 32bit data */
284			child->thread.insn2 = (short)far_epc_insn;
285		} else {
286			child->thread.insn2_type = 1;
287			child->thread.addr2 = far_epc;
288			child->thread.insn2 = far_epc_insn;
289		}
290	}
291}
292
293void user_disable_single_step(struct task_struct *child)
294{
295	if (child->thread.insn1_type == 0)
296		write_tsk_short(child, child->thread.addr1,
297				child->thread.insn1);
298
299	if (child->thread.insn1_type == 1)
300		write_tsk_long(child, child->thread.addr1,
301				child->thread.insn1);
302
303	if (child->thread.ss_nextcnt == 2) {	/* branch */
304		if (child->thread.insn1_type == 0)
305			write_tsk_short(child, child->thread.addr1,
306					child->thread.insn1);
307		if (child->thread.insn1_type == 1)
308			write_tsk_long(child, child->thread.addr1,
309					child->thread.insn1);
310		if (child->thread.insn2_type == 0)
311			write_tsk_short(child, child->thread.addr2,
312					child->thread.insn2);
313		if (child->thread.insn2_type == 1)
314			write_tsk_long(child, child->thread.addr2,
315					child->thread.insn2);
316	}
317
318	child->thread.single_step = 0;
319	child->thread.ss_nextcnt = 0;
320}
321
322void ptrace_disable(struct task_struct *child)
323{
324	user_disable_single_step(child);
325}
326
327long
328arch_ptrace(struct task_struct *child, long request,
329	    unsigned long addr, unsigned long data)
330{
331	int ret;
332	unsigned long __user *datap = (void __user *)data;
333
334	switch (request) {
335	case PTRACE_GETREGS:
336		ret = copy_regset_to_user(child, &user_score_native_view,
337						REGSET_GENERAL,
338						0, sizeof(struct pt_regs),
339						datap);
340		break;
341
342	case PTRACE_SETREGS:
343		ret = copy_regset_from_user(child, &user_score_native_view,
344						REGSET_GENERAL,
345						0, sizeof(struct pt_regs),
346						datap);
347		break;
348
349	default:
350		ret = ptrace_request(child, request, addr, data);
351		break;
352	}
353
354	return ret;
355}
356
357/*
358 * Notification of system call entry/exit
359 * - triggered by current->work.syscall_trace
360 */
361asmlinkage void do_syscall_trace(struct pt_regs *regs, int entryexit)
362{
363	if (!(current->ptrace & PT_PTRACED))
364		return;
365
366	if (!test_thread_flag(TIF_SYSCALL_TRACE))
367		return;
368
369	/* The 0x80 provides a way for the tracing parent to distinguish
370	   between a syscall stop and SIGTRAP delivery. */
371	ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ?
372			0x80 : 0));
373
374	/*
375	 * this isn't the same as continuing with a signal, but it will do
376	 * for normal use.  strace only continues with a signal if the
377	 * stopping signal is not SIGTRAP.  -brl
378	 */
379	if (current->exit_code) {
380		send_sig(current->exit_code, current, 1);
381		current->exit_code = 0;
382	}
383}
384