[mirror_ubuntu-hirsute-kernel.git] / arch / microblaze / kernel / ptrace.c

/*
 * `ptrace' system call
 *
 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
 * Copyright (C) 2007-2009 PetaLogix
 * Copyright (C) 2004-2007 John Williams <john.williams@petalogix.com>
 *
 * derived from arch/v850/kernel/ptrace.c
 *
 * Copyright (C) 2002,03 NEC Electronics Corporation
 * Copyright (C) 2002,03 Miles Bader <miles@gnu.org>
 *
 * Derived from arch/mips/kernel/ptrace.c:
 *
 * Copyright (C) 1992 Ross Biro
 * Copyright (C) Linus Torvalds
 * Copyright (C) 1994, 95, 96, 97, 98, 2000 Ralf Baechle
 * Copyright (C) 1996 David S. Miller
 * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
 * Copyright (C) 1999 MIPS Technologies, Inc.
 *
 * This file is subject to the terms and conditions of the GNU General
 * Public License. See the file COPYING in the main directory of this
 * archive for more details.
 */

#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/ptrace.h>
#include <linux/signal.h>

#include <linux/errno.h>
#include <asm/processor.h>
#include <linux/uaccess.h>
#include <asm/asm-offsets.h>

/* Returns the address where the register at REG_OFFS in P is stashed away. */
static microblaze_reg_t *reg_save_addr(unsigned reg_offs,
					struct task_struct *t)
{
	struct pt_regs *regs;

	/*
	 * Three basic cases:
	 *
	 * (1)	A register normally saved before calling the scheduler, is
	 *	available in the kernel entry pt_regs structure at the top
	 *	of the kernel stack. The kernel trap/irq exit path takes
	 *	care to save/restore almost all registers for ptrace'd
	 *	processes.
	 *
	 * (2)	A call-clobbered register, where the process P entered the
	 *	kernel via [syscall] trap, is not stored anywhere; that's
	 *	OK, because such registers are not expected to be preserved
	 *	when the trap returns anyway (so we don't actually bother to
	 *	test for this case).
	 *
	 * (3)	A few registers not used at all by the kernel, and so
	 *	normally never saved except by context-switches, are in the
	 *	context switch state.
	 */

	/* Register saved during kernel entry (or not available). */
	regs = task_pt_regs(t);

	return (microblaze_reg_t *)((char *)regs + reg_offs);
}

long arch_ptrace(struct task_struct *child, long request, long addr, long data)
{
	int rval;
	unsigned long val = 0;
	unsigned long copied;

	switch (request) {
	case PTRACE_PEEKTEXT: /* read word at location addr. */
	case PTRACE_PEEKDATA:
		pr_debug("PEEKTEXT/PEEKDATA at %08lX\n", addr);
		copied = access_process_vm(child, addr, &val, sizeof(val), 0);
		rval = -EIO;
		if (copied != sizeof(val))
			break;
		rval = put_user(val, (unsigned long *)data);
		break;

	case PTRACE_POKETEXT: /* write the word at location addr. */
	case PTRACE_POKEDATA:
		pr_debug("POKETEXT/POKEDATA to %08lX\n", addr);
		rval = 0;
		if (access_process_vm(child, addr, &data, sizeof(data), 1)
		    == sizeof(data))
			break;
		rval = -EIO;
		break;

	/* Read/write the word at location ADDR in the registers. */
	case PTRACE_PEEKUSR:
	case PTRACE_POKEUSR:
		pr_debug("PEEKUSR/POKEUSR : 0x%08lx\n", addr);
		rval = 0;
		if (addr >= PT_SIZE && request == PTRACE_PEEKUSR) {
			/*
			 * Special requests that don't actually correspond
			 * to offsets in struct pt_regs.
			 */
			if (addr == PT_TEXT_ADDR) {
				val = child->mm->start_code;
			} else if (addr == PT_DATA_ADDR) {
				val = child->mm->start_data;
			} else if (addr == PT_TEXT_LEN) {
				val = child->mm->end_code
					- child->mm->start_code;
			} else {
				rval = -EIO;
			}
		} else if (addr >= 0 && addr < PT_SIZE && (addr & 0x3) == 0) {
			microblaze_reg_t *reg_addr = reg_save_addr(addr, child);
			if (request == PTRACE_PEEKUSR)
				val = *reg_addr;
			else
				*reg_addr = data;
		} else
			rval = -EIO;

		if (rval == 0 && request == PTRACE_PEEKUSR)
			rval = put_user(val, (unsigned long *)data);
		break;
	/* Continue and stop at next (return from) syscall */
	case PTRACE_SYSCALL:
		pr_debug("PTRACE_SYSCALL\n");
	case PTRACE_SINGLESTEP:
		pr_debug("PTRACE_SINGLESTEP\n");
	/* Restart after a signal.  */
	case PTRACE_CONT:
		pr_debug("PTRACE_CONT\n");
		rval = -EIO;
		if (!valid_signal(data))
			break;

		if (request == PTRACE_SYSCALL)
			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
		else
			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);

		child->exit_code = data;
		pr_debug("wakeup_process\n");
		wake_up_process(child);
		rval = 0;
		break;

	/*
	 * make the child exit.  Best I can do is send it a sigkill.
	 * perhaps it should be put in the status that it wants to
	 * exit.
	 */
	case PTRACE_KILL:
		pr_debug("PTRACE_KILL\n");
		rval = 0;
		if (child->exit_state == EXIT_ZOMBIE)	/* already dead */
			break;
		child->exit_code = SIGKILL;
		wake_up_process(child);
		break;

	case PTRACE_DETACH: /* detach a process that was attached. */
		pr_debug("PTRACE_DETACH\n");
		rval = ptrace_detach(child, data);
		break;
	default:
		/* rval = ptrace_request(child, request, addr, data); noMMU */
		rval = -EIO;
	}
	return rval;
}

void ptrace_disable(struct task_struct *child)
{
	/* nothing to do */
}
Commit	Line	Data
2b438454 MS	1	/*
	2	* `ptrace' system call
	3	*
	4	* Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
	5	* Copyright (C) 2007-2009 PetaLogix
	6	* Copyright (C) 2004-2007 John Williams <john.williams@petalogix.com>
	7	*
	8	* derived from arch/v850/kernel/ptrace.c
	9	*
	10	* Copyright (C) 2002,03 NEC Electronics Corporation
	11	* Copyright (C) 2002,03 Miles Bader <miles@gnu.org>
	12	*
	13	* Derived from arch/mips/kernel/ptrace.c:
	14	*
	15	* Copyright (C) 1992 Ross Biro
	16	* Copyright (C) Linus Torvalds
	17	* Copyright (C) 1994, 95, 96, 97, 98, 2000 Ralf Baechle
	18	* Copyright (C) 1996 David S. Miller
	19	* Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
	20	* Copyright (C) 1999 MIPS Technologies, Inc.
	21	*
	22	* This file is subject to the terms and conditions of the GNU General
	23	* Public License. See the file COPYING in the main directory of this
	24	* archive for more details.
	25	*/
	26
	27	#include <linux/kernel.h>
	28	#include <linux/mm.h>
	29	#include <linux/sched.h>
2b438454 MS	30	#include <linux/ptrace.h>
	31	#include <linux/signal.h>
	32
	33	#include <linux/errno.h>
2b438454 MS	34	#include <asm/processor.h>
	35	#include <linux/uaccess.h>
	36	#include <asm/asm-offsets.h>
	37
	38	/* Returns the address where the register at REG_OFFS in P is stashed away. */
	39	static microblaze_reg_t *reg_save_addr(unsigned reg_offs,
	40	struct task_struct *t)
	41	{
	42	struct pt_regs *regs;
	43
	44	/*
	45	* Three basic cases:
	46	*
	47	* (1) A register normally saved before calling the scheduler, is
	48	* available in the kernel entry pt_regs structure at the top
	49	* of the kernel stack. The kernel trap/irq exit path takes
	50	* care to save/restore almost all registers for ptrace'd
	51	* processes.
	52	*
	53	* (2) A call-clobbered register, where the process P entered the
	54	* kernel via [syscall] trap, is not stored anywhere; that's
	55	* OK, because such registers are not expected to be preserved
	56	* when the trap returns anyway (so we don't actually bother to
	57	* test for this case).
	58	*
	59	* (3) A few registers not used at all by the kernel, and so
	60	* normally never saved except by context-switches, are in the
	61	* context switch state.
	62	*/
	63
	64	/* Register saved during kernel entry (or not available). */
	65	regs = task_pt_regs(t);
	66
	67	return (microblaze_reg_t )((char )regs + reg_offs);
	68	}
	69
	70	long arch_ptrace(struct task_struct *child, long request, long addr, long data)
	71	{
	72	int rval;
	73	unsigned long val = 0;
	74	unsigned long copied;
	75
	76	switch (request) {
	77	case PTRACE_PEEKTEXT: /* read word at location addr. */
	78	case PTRACE_PEEKDATA:
	79	pr_debug("PEEKTEXT/PEEKDATA at %08lX\n", addr);
	80	copied = access_process_vm(child, addr, &val, sizeof(val), 0);
	81	rval = -EIO;
	82	if (copied != sizeof(val))
	83	break;
	84	rval = put_user(val, (unsigned long *)data);
	85	break;
	86
	87	case PTRACE_POKETEXT: /* write the word at location addr. */
	88	case PTRACE_POKEDATA:
	89	pr_debug("POKETEXT/POKEDATA to %08lX\n", addr);
	90	rval = 0;
	91	if (access_process_vm(child, addr, &data, sizeof(data), 1)
	92	== sizeof(data))
	93	break;
	94	rval = -EIO;
	95	break;
	96
	97	/* Read/write the word at location ADDR in the registers. */
98	case PTRACE_PEEKUSR:
99	case PTRACE_POKEUSR:
100	pr_debug("PEEKUSR/POKEUSR : 0x%08lx\n", addr);
101	rval = 0;
102	if (addr >= PT_SIZE && request == PTRACE_PEEKUSR) {
103	/*
104	* Special requests that don't actually correspond
105	* to offsets in struct pt_regs.
106	*/
107	if (addr == PT_TEXT_ADDR) {
108	val = child->mm->start_code;
109	} else if (addr == PT_DATA_ADDR) {
110	val = child->mm->start_data;
111	} else if (addr == PT_TEXT_LEN) {
112	val = child->mm->end_code
113	- child->mm->start_code;
114	} else {
115	rval = -EIO;
116	}
117	} else if (addr >= 0 && addr < PT_SIZE && (addr & 0x3) == 0) {
118	microblaze_reg_t *reg_addr = reg_save_addr(addr, child);
119	if (request == PTRACE_PEEKUSR)
120	val = *reg_addr;
121	else
122	*reg_addr = data;
123	} else
124	rval = -EIO;
125
126	if (rval == 0 && request == PTRACE_PEEKUSR)
127	rval = put_user(val, (unsigned long *)data);
128	break;
129	/* Continue and stop at next (return from) syscall */
130	case PTRACE_SYSCALL:
131	pr_debug("PTRACE_SYSCALL\n");
132	case PTRACE_SINGLESTEP:
133	pr_debug("PTRACE_SINGLESTEP\n");
134	/* Restart after a signal. */
135	case PTRACE_CONT:
136	pr_debug("PTRACE_CONT\n");
137	rval = -EIO;
138	if (!valid_signal(data))
139	break;
140
141	if (request == PTRACE_SYSCALL)
142	set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
143	else
144	clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
145
146	child->exit_code = data;
147	pr_debug("wakeup_process\n");
148	wake_up_process(child);
149	rval = 0;
150	break;
151
152	/*
153	* make the child exit. Best I can do is send it a sigkill.
154	* perhaps it should be put in the status that it wants to
155	* exit.
156	*/
157	case PTRACE_KILL:
158	pr_debug("PTRACE_KILL\n");
159	rval = 0;
160	if (child->exit_state == EXIT_ZOMBIE) /* already dead */
161	break;
162	child->exit_code = SIGKILL;
163	wake_up_process(child);
164	break;
165
166	case PTRACE_DETACH: /* detach a process that was attached. */
167	pr_debug("PTRACE_DETACH\n");
168	rval = ptrace_detach(child, data);
169	break;
170	default:
171	/* rval = ptrace_request(child, request, addr, data); noMMU */
172	rval = -EIO;
173	}
174	return rval;
175	}
176
177	void ptrace_disable(struct task_struct *child)
178	{
179	/* nothing to do */
180	}