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/arch/m68k/kernel/ptrace.c

https://bitbucket.org/evzijst/gittest
C | 393 lines | 296 code | 39 blank | 58 comment | 65 complexity | a812cfa6ef06818fedadbd50cecfcb80 MD5 | raw file
  1/*
  2 *  linux/arch/m68k/kernel/ptrace.c
  3 *
  4 *  Copyright (C) 1994 by Hamish Macdonald
  5 *  Taken from linux/kernel/ptrace.c and modified for M680x0.
  6 *  linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
  7 *
  8 * This file is subject to the terms and conditions of the GNU General
  9 * Public License.  See the file COPYING in the main directory of
 10 * this archive for more details.
 11 */
 12
 13#include <linux/kernel.h>
 14#include <linux/sched.h>
 15#include <linux/mm.h>
 16#include <linux/smp.h>
 17#include <linux/smp_lock.h>
 18#include <linux/errno.h>
 19#include <linux/ptrace.h>
 20#include <linux/user.h>
 21#include <linux/config.h>
 22
 23#include <asm/uaccess.h>
 24#include <asm/page.h>
 25#include <asm/pgtable.h>
 26#include <asm/system.h>
 27#include <asm/processor.h>
 28
 29/*
 30 * does not yet catch signals sent when the child dies.
 31 * in exit.c or in signal.c.
 32 */
 33
 34/* determines which bits in the SR the user has access to. */
 35/* 1 = access 0 = no access */
 36#define SR_MASK 0x001f
 37
 38/* sets the trace bits. */
 39#define TRACE_BITS 0x8000
 40
 41/* Find the stack offset for a register, relative to thread.esp0. */
 42#define PT_REG(reg)	((long)&((struct pt_regs *)0)->reg)
 43#define SW_REG(reg)	((long)&((struct switch_stack *)0)->reg \
 44			 - sizeof(struct switch_stack))
 45/* Mapping from PT_xxx to the stack offset at which the register is
 46   saved.  Notice that usp has no stack-slot and needs to be treated
 47   specially (see get_reg/put_reg below). */
 48static int regoff[] = {
 49	[0]	= PT_REG(d1),
 50	[1]	= PT_REG(d2),
 51	[2]	= PT_REG(d3),
 52	[3]	= PT_REG(d4),
 53	[4]	= PT_REG(d5),
 54	[5]	= SW_REG(d6),
 55	[6]	= SW_REG(d7),
 56	[7]	= PT_REG(a0),
 57	[8]	= PT_REG(a1),
 58	[9]	= PT_REG(a2),
 59	[10]	= SW_REG(a3),
 60	[11]	= SW_REG(a4),
 61	[12]	= SW_REG(a5),
 62	[13]	= SW_REG(a6),
 63	[14]	= PT_REG(d0),
 64	[15]	= -1,
 65	[16]	= PT_REG(orig_d0),
 66	[17]	= PT_REG(sr),
 67	[18]	= PT_REG(pc),
 68};
 69
 70/*
 71 * Get contents of register REGNO in task TASK.
 72 */
 73static inline long get_reg(struct task_struct *task, int regno)
 74{
 75	unsigned long *addr;
 76
 77	if (regno == PT_USP)
 78		addr = &task->thread.usp;
 79	else if (regno < sizeof(regoff)/sizeof(regoff[0]))
 80		addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
 81	else
 82		return 0;
 83	return *addr;
 84}
 85
 86/*
 87 * Write contents of register REGNO in task TASK.
 88 */
 89static inline int put_reg(struct task_struct *task, int regno,
 90			  unsigned long data)
 91{
 92	unsigned long *addr;
 93
 94	if (regno == PT_USP)
 95		addr = &task->thread.usp;
 96	else if (regno < sizeof(regoff)/sizeof(regoff[0]))
 97		addr = (unsigned long *) (task->thread.esp0 + regoff[regno]);
 98	else
 99		return -1;
100	*addr = data;
101	return 0;
102}
103
104/*
105 * Called by kernel/ptrace.c when detaching..
106 *
107 * Make sure the single step bit is not set.
108 */
109void ptrace_disable(struct task_struct *child)
110{
111	unsigned long tmp;
112	/* make sure the single step bit is not set. */
113	tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
114	put_reg(child, PT_SR, tmp);
115	child->thread.work.delayed_trace = 0;
116	child->thread.work.syscall_trace = 0;
117}
118
119asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
120{
121	struct task_struct *child;
122	int ret;
123
124	lock_kernel();
125	ret = -EPERM;
126	if (request == PTRACE_TRACEME) {
127		/* are we already being traced? */
128		if (current->ptrace & PT_PTRACED)
129			goto out;
130		/* set the ptrace bit in the process flags. */
131		current->ptrace |= PT_PTRACED;
132		ret = 0;
133		goto out;
134	}
135	ret = -ESRCH;
136	read_lock(&tasklist_lock);
137	child = find_task_by_pid(pid);
138	if (child)
139		get_task_struct(child);
140	read_unlock(&tasklist_lock);
141	if (!child)
142		goto out;
143
144	ret = -EPERM;
145	if (pid == 1)		/* you may not mess with init */
146		goto out_tsk;
147
148	if (request == PTRACE_ATTACH) {
149		ret = ptrace_attach(child);
150		goto out_tsk;
151	}
152
153	ret = ptrace_check_attach(child, request == PTRACE_KILL);
154	if (ret < 0)
155		goto out_tsk;
156
157	switch (request) {
158	/* when I and D space are separate, these will need to be fixed. */
159		case PTRACE_PEEKTEXT: /* read word at location addr. */
160		case PTRACE_PEEKDATA: {
161			unsigned long tmp;
162			int copied;
163
164			copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
165			ret = -EIO;
166			if (copied != sizeof(tmp))
167				break;
168			ret = put_user(tmp,(unsigned long *) data);
169			break;
170		}
171
172	/* read the word at location addr in the USER area. */
173		case PTRACE_PEEKUSR: {
174			unsigned long tmp;
175
176			ret = -EIO;
177			if ((addr & 3) || addr < 0 ||
178			    addr > sizeof(struct user) - 3)
179				break;
180
181			tmp = 0;  /* Default return condition */
182			addr = addr >> 2; /* temporary hack. */
183			ret = -EIO;
184			if (addr < 19) {
185				tmp = get_reg(child, addr);
186				if (addr == PT_SR)
187					tmp >>= 16;
188			} else if (addr >= 21 && addr < 49) {
189				tmp = child->thread.fp[addr - 21];
190#ifdef CONFIG_M68KFPU_EMU
191				/* Convert internal fpu reg representation
192				 * into long double format
193				 */
194				if (FPU_IS_EMU && (addr < 45) && !(addr % 3))
195					tmp = ((tmp & 0xffff0000) << 15) |
196					      ((tmp & 0x0000ffff) << 16);
197#endif
198			} else
199				break;
200			ret = put_user(tmp,(unsigned long *) data);
201			break;
202		}
203
204      /* when I and D space are separate, this will have to be fixed. */
205		case PTRACE_POKETEXT: /* write the word at location addr. */
206		case PTRACE_POKEDATA:
207			ret = 0;
208			if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
209				break;
210			ret = -EIO;
211			break;
212
213		case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
214			ret = -EIO;
215			if ((addr & 3) || addr < 0 ||
216			    addr > sizeof(struct user) - 3)
217				break;
218
219			addr = addr >> 2; /* temporary hack. */
220
221			if (addr == PT_SR) {
222				data &= SR_MASK;
223				data <<= 16;
224				data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
225			}
226			if (addr < 19) {
227				if (put_reg(child, addr, data))
228					break;
229				ret = 0;
230				break;
231			}
232			if (addr >= 21 && addr < 48)
233			{
234#ifdef CONFIG_M68KFPU_EMU
235				/* Convert long double format
236				 * into internal fpu reg representation
237				 */
238				if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) {
239					data = (unsigned long)data << 15;
240					data = (data & 0xffff0000) |
241					       ((data & 0x0000ffff) >> 1);
242				}
243#endif
244				child->thread.fp[addr - 21] = data;
245				ret = 0;
246			}
247			break;
248
249		case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
250		case PTRACE_CONT: { /* restart after signal. */
251			long tmp;
252
253			ret = -EIO;
254			if ((unsigned long) data > _NSIG)
255				break;
256			if (request == PTRACE_SYSCALL) {
257					child->thread.work.syscall_trace = ~0;
258			} else {
259					child->thread.work.syscall_trace = 0;
260			}
261			child->exit_code = data;
262			/* make sure the single step bit is not set. */
263			tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
264			put_reg(child, PT_SR, tmp);
265			child->thread.work.delayed_trace = 0;
266			wake_up_process(child);
267			ret = 0;
268			break;
269		}
270
271/*
272 * make the child exit.  Best I can do is send it a sigkill.
273 * perhaps it should be put in the status that it wants to
274 * exit.
275 */
276		case PTRACE_KILL: {
277			long tmp;
278
279			ret = 0;
280			if (child->exit_state == EXIT_ZOMBIE) /* already dead */
281				break;
282			child->exit_code = SIGKILL;
283	/* make sure the single step bit is not set. */
284			tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
285			put_reg(child, PT_SR, tmp);
286			child->thread.work.delayed_trace = 0;
287			wake_up_process(child);
288			break;
289		}
290
291		case PTRACE_SINGLESTEP: {  /* set the trap flag. */
292			long tmp;
293
294			ret = -EIO;
295			if ((unsigned long) data > _NSIG)
296				break;
297			child->thread.work.syscall_trace = 0;
298			tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16);
299			put_reg(child, PT_SR, tmp);
300			child->thread.work.delayed_trace = 1;
301
302			child->exit_code = data;
303	/* give it a chance to run. */
304			wake_up_process(child);
305			ret = 0;
306			break;
307		}
308
309		case PTRACE_DETACH:	/* detach a process that was attached. */
310			ret = ptrace_detach(child, data);
311			break;
312
313		case PTRACE_GETREGS: { /* Get all gp regs from the child. */
314			int i;
315			unsigned long tmp;
316			for (i = 0; i < 19; i++) {
317			    tmp = get_reg(child, i);
318			    if (i == PT_SR)
319				tmp >>= 16;
320			    if (put_user(tmp, (unsigned long *) data)) {
321				ret = -EFAULT;
322				break;
323			    }
324			    data += sizeof(long);
325			}
326			ret = 0;
327			break;
328		}
329
330		case PTRACE_SETREGS: { /* Set all gp regs in the child. */
331			int i;
332			unsigned long tmp;
333			for (i = 0; i < 19; i++) {
334			    if (get_user(tmp, (unsigned long *) data)) {
335				ret = -EFAULT;
336				break;
337			    }
338			    if (i == PT_SR) {
339				tmp &= SR_MASK;
340				tmp <<= 16;
341				tmp |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
342			    }
343			    put_reg(child, i, tmp);
344			    data += sizeof(long);
345			}
346			ret = 0;
347			break;
348		}
349
350		case PTRACE_GETFPREGS: { /* Get the child FPU state. */
351			ret = 0;
352			if (copy_to_user((void *)data, &child->thread.fp,
353					 sizeof(struct user_m68kfp_struct)))
354				ret = -EFAULT;
355			break;
356		}
357
358		case PTRACE_SETFPREGS: { /* Set the child FPU state. */
359			ret = 0;
360			if (copy_from_user(&child->thread.fp, (void *)data,
361					   sizeof(struct user_m68kfp_struct)))
362				ret = -EFAULT;
363			break;
364		}
365
366		default:
367			ret = ptrace_request(child, request, addr, data);
368			break;
369	}
370out_tsk:
371	put_task_struct(child);
372out:
373	unlock_kernel();
374	return ret;
375}
376
377asmlinkage void syscall_trace(void)
378{
379	if (!current->thread.work.delayed_trace &&
380	    !current->thread.work.syscall_trace)
381		return;
382	ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
383				 ? 0x80 : 0));
384	/*
385	 * this isn't the same as continuing with a signal, but it will do
386	 * for normal use.  strace only continues with a signal if the
387	 * stopping signal is not SIGTRAP.  -brl
388	 */
389	if (current->exit_code) {
390		send_sig(current->exit_code, current, 1);
391		current->exit_code = 0;
392	}
393}