[deliverable/linux.git] / arch / v850 / kernel / ptrace.c

/*
 * arch/v850/kernel/ptrace.c -- `ptrace' system call
 *
 *  Copyright (C) 2002,03,04  NEC Electronics Corporation
 *  Copyright (C) 2002,03,04  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 <asm/errno.h>
#include <asm/ptrace.h>
#include <asm/processor.h>
#include <asm/uaccess.h>

/* Returns the address where the register at REG_OFFS in P is stashed away.  */
static v850_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.  */

	if (reg_offs == PT_CTPC || reg_offs == PT_CTPSW || reg_offs == PT_CTBP)
		/* Register saved during context switch.  */
		regs = thread_saved_regs (t);
	else
		/* Register saved during kernel entry (or not available).  */
		regs = task_pt_regs (t);

	return (v850_reg_t *)((char *)regs + reg_offs);
}

/* Set the bits SET and clear the bits CLEAR in the v850e DIR
   (`debug information register').  Returns the new value of DIR.  */
static inline v850_reg_t set_dir (v850_reg_t set, v850_reg_t clear)
{
	register v850_reg_t rval asm ("r10");
	register v850_reg_t arg0 asm ("r6") = set;
	register v850_reg_t arg1 asm ("r7") = clear;

	/* The dbtrap handler has exactly this functionality when called
	   from kernel mode.  0xf840 is a `dbtrap' insn.  */
	asm (".short 0xf840" : "=r" (rval) : "r" (arg0), "r" (arg1));

	return rval;
}

/* Makes sure hardware single-stepping is (globally) enabled.
   Returns true if successful.  */
static inline int enable_single_stepping (void)
{
	static int enabled = 0;	/* Remember whether we already did it.  */
	if (! enabled) {
		/* Turn on the SE (`single-step enable') bit, 0x100, in the
		   DIR (`debug information register').  This may fail if a
		   processor doesn't support it or something.  We also try
		   to clear bit 0x40 (`INI'), which is necessary to use the
		   debug stuff on the v850e2; on the v850e, clearing 0x40
		   shouldn't cause any problem.  */
		v850_reg_t dir = set_dir (0x100, 0x40);
		/* Make sure it really got set.  */
		if (dir & 0x100)
			enabled = 1;
	}
	return enabled;
}

/* Try to set CHILD's single-step flag to VAL.  Returns true if successful.  */
static int set_single_step (struct task_struct *t, int val)
{
	v850_reg_t *psw_addr = reg_save_addr(PT_PSW, t);
	if (val) {
		/* Make sure single-stepping is enabled.  */
		if (! enable_single_stepping ())
			return 0;
		/* Set T's single-step flag.  */
		*psw_addr |= 0x800;
	} else
		*psw_addr &= ~0x800;
	return 1;
}

long arch_ptrace(struct task_struct *child, long request, long addr, long data)
{
	int rval;

	switch (request) {
		unsigned long val;

	case PTRACE_PEEKTEXT: /* read word at location addr. */
	case PTRACE_PEEKDATA:
		rval = generic_ptrace_peekdata(child, addr, data);
		goto out;

	case PTRACE_POKETEXT: /* write the word at location addr. */
	case PTRACE_POKEDATA:
		rval = 0;
		if (access_process_vm(child, addr, &data, sizeof(data), 1)
		    == sizeof(data))
			break;
		rval = -EIO;
		goto out;

	/* Read/write the word at location ADDR in the registers.  */
	case PTRACE_PEEKUSR:
	case PTRACE_POKEUSR:
		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) {
			v850_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);
		goto out;

	/* Continue and stop at next (return from) syscall */
	case PTRACE_SYSCALL:
	/* Restart after a signal.  */
	case PTRACE_CONT:
	/* Execute a single instruction. */
	case PTRACE_SINGLESTEP:
		rval = -EIO;
		if (!valid_signal(data))
			break;

		/* Turn CHILD's single-step flag on or off.  */
		if (! set_single_step (child, request == PTRACE_SINGLESTEP))
			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;
		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:
		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. */
		set_single_step (child, 0);  /* Clear single-step flag */
		rval = ptrace_detach(child, data);
		break;

	default:
		rval = -EIO;
		goto out;
	}
 out:
	return rval;
}

asmlinkage void syscall_trace(void)
{
	if (!test_thread_flag(TIF_SYSCALL_TRACE))
		return;
	if (!(current->ptrace & PT_PTRACED))
		return;
	/* The 0x80 provides a way for the tracing parent to distinguish
	   between a syscall stop and SIGTRAP delivery */
	ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
				 ? 0x80 : 0));
	/*
	 * this isn't the same as continuing with a signal, but it will do
	 * for normal use.  strace only continues with a signal if the
	 * stopping signal is not SIGTRAP.  -brl
	 */
	if (current->exit_code) {
		send_sig(current->exit_code, current, 1);
		current->exit_code = 0;
	}
}

void ptrace_disable (struct task_struct *child)
{
	/* nothing to do */
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* arch/v850/kernel/ptrace.c -- `ptrace' system call
	3	*
	4	* Copyright (C) 2002,03,04 NEC Electronics Corporation
	5	* Copyright (C) 2002,03,04 Miles Bader <miles@gnu.org>
	6	*
	7	* Derived from arch/mips/kernel/ptrace.c:
	8	*
	9	* Copyright (C) 1992 Ross Biro
	10	* Copyright (C) Linus Torvalds
	11	* Copyright (C) 1994, 95, 96, 97, 98, 2000 Ralf Baechle
	12	* Copyright (C) 1996 David S. Miller
	13	* Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
	14	* Copyright (C) 1999 MIPS Technologies, Inc.
	15	*
	16	* This file is subject to the terms and conditions of the GNU General
	17	* Public License. See the file COPYING in the main directory of this
	18	* archive for more details.
	19	*/
	20
	21	#include <linux/kernel.h>
	22	#include <linux/mm.h>
	23	#include <linux/sched.h>
1da177e4	24	#include <linux/ptrace.h>
7ed20e1a	25	#include <linux/signal.h>
1da177e4 LT	26
	27	#include <asm/errno.h>
	28	#include <asm/ptrace.h>
	29	#include <asm/processor.h>
	30	#include <asm/uaccess.h>
	31
	32	/* Returns the address where the register at REG_OFFS in P is stashed away. */
	33	static v850_reg_t reg_save_addr (unsigned reg_offs, struct task_struct t)
	34	{
	35	struct pt_regs *regs;
	36
	37	/* Three basic cases:
	38
	39	(1) A register normally saved before calling the scheduler, is
	40	available in the kernel entry pt_regs structure at the top
	41	of the kernel stack. The kernel trap/irq exit path takes
	42	care to save/restore almost all registers for ptrace'd
	43	processes.
	44
	45	(2) A call-clobbered register, where the process P entered the
	46	kernel via [syscall] trap, is not stored anywhere; that's
	47	OK, because such registers are not expected to be preserved
	48	when the trap returns anyway (so we don't actually bother to
	49	test for this case).
	50
	51	(3) A few registers not used at all by the kernel, and so
	52	normally never saved except by context-switches, are in the
	53	context switch state. */
	54
	55	if (reg_offs == PT_CTPC \|\| reg_offs == PT_CTPSW \|\| reg_offs == PT_CTBP)
	56	/* Register saved during context switch. */
	57	regs = thread_saved_regs (t);
	58	else
	59	/* Register saved during kernel entry (or not available). */
b7f6961d	60	regs = task_pt_regs (t);
1da177e4 LT	61
	62	return (v850_reg_t )((char )regs + reg_offs);
	63	}
	64
	65	/* Set the bits SET and clear the bits CLEAR in the v850e DIR
	66	(`debug information register'). Returns the new value of DIR. */
	67	static inline v850_reg_t set_dir (v850_reg_t set, v850_reg_t clear)
	68	{
	69	register v850_reg_t rval asm ("r10");
	70	register v850_reg_t arg0 asm ("r6") = set;
	71	register v850_reg_t arg1 asm ("r7") = clear;
	72
	73	/* The dbtrap handler has exactly this functionality when called
	74	from kernel mode. 0xf840 is a `dbtrap' insn. */
	75	asm (".short 0xf840" : "=r" (rval) : "r" (arg0), "r" (arg1));
	76
	77	return rval;
	78	}
	79
	80	/* Makes sure hardware single-stepping is (globally) enabled.
	81	Returns true if successful. */
	82	static inline int enable_single_stepping (void)
	83	{
	84	static int enabled = 0; /* Remember whether we already did it. */
	85	if (! enabled) {
	86	/* Turn on the SE (`single-step enable') bit, 0x100, in the
	87	DIR (`debug information register'). This may fail if a
	88	processor doesn't support it or something. We also try
	89	to clear bit 0x40 (`INI'), which is necessary to use the
	90	debug stuff on the v850e2; on the v850e, clearing 0x40
	91	shouldn't cause any problem. */
	92	v850_reg_t dir = set_dir (0x100, 0x40);
	93	/* Make sure it really got set. */
	94	if (dir & 0x100)
	95	enabled = 1;
	96	}
	97	return enabled;
	98	}
	99
	100	/* Try to set CHILD's single-step flag to VAL. Returns true if successful. */
	101	static int set_single_step (struct task_struct *t, int val)
	102	{
	103	v850_reg_t *psw_addr = reg_save_addr(PT_PSW, t);
	104	if (val) {
	105	/* Make sure single-stepping is enabled. */
	106	if (! enable_single_stepping ())
	107	return 0;
	108	/* Set T's single-step flag. */
	109	*psw_addr \|= 0x800;
	110	} else
	111	*psw_addr &= ~0x800;
	112	return 1;
	113	}
	114
481bed45	115	long arch_ptrace(struct task_struct *child, long request, long addr, long data)
1da177e4	116	{
1da177e4 LT	117	int rval;
1da177e4 LT	118
1da177e4	119	switch (request) {
76647323	120	unsigned long val;
1da177e4 LT	121
	122	case PTRACE_PEEKTEXT: /* read word at location addr. */
	123	case PTRACE_PEEKDATA:
76647323	124	rval = generic_ptrace_peekdata(child, addr, data);
1da177e4 LT	125	goto out;
	126
	127	case PTRACE_POKETEXT: /* write the word at location addr. */
	128	case PTRACE_POKEDATA:
	129	rval = 0;
	130	if (access_process_vm(child, addr, &data, sizeof(data), 1)
	131	== sizeof(data))
	132	break;
	133	rval = -EIO;
	134	goto out;
	135
	136	/* Read/write the word at location ADDR in the registers. */
	137	case PTRACE_PEEKUSR:
	138	case PTRACE_POKEUSR:
	139	rval = 0;
	140	if (addr >= PT_SIZE && request == PTRACE_PEEKUSR) {
	141	/* Special requests that don't actually correspond
	142	to offsets in struct pt_regs. */
	143	if (addr == PT_TEXT_ADDR)
	144	val = child->mm->start_code;
	145	else if (addr == PT_DATA_ADDR)
	146	val = child->mm->start_data;
	147	else if (addr == PT_TEXT_LEN)
	148	val = child->mm->end_code
	149	- child->mm->start_code;
	150	else
	151	rval = -EIO;
	152	} else if (addr >= 0 && addr < PT_SIZE && (addr & 0x3) == 0) {
	153	v850_reg_t *reg_addr = reg_save_addr(addr, child);
	154	if (request == PTRACE_PEEKUSR)
	155	val = *reg_addr;
	156	else
	157	*reg_addr = data;
	158	} else
	159	rval = -EIO;
	160
	161	if (rval == 0 && request == PTRACE_PEEKUSR)
	162	rval = put_user (val, (unsigned long *)data);
	163	goto out;
	164
	165	/* Continue and stop at next (return from) syscall */
	166	case PTRACE_SYSCALL:
	167	/* Restart after a signal. */
	168	case PTRACE_CONT:
	169	/* Execute a single instruction. */
	170	case PTRACE_SINGLESTEP:
	171	rval = -EIO;
7ed20e1a	172	if (!valid_signal(data))
1da177e4 LT	173	break;
	174
	175	/* Turn CHILD's single-step flag on or off. */
	176	if (! set_single_step (child, request == PTRACE_SINGLESTEP))
	177	break;
	178
	179	if (request == PTRACE_SYSCALL)
	180	set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
	181	else
	182	clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
	183
	184	child->exit_code = data;
	185	wake_up_process(child);
	186	rval = 0;
	187	break;
	188
	189	/*
	190	* make the child exit. Best I can do is send it a sigkill.
	191	* perhaps it should be put in the status that it wants to
	192	* exit.
	193	*/
	194	case PTRACE_KILL:
	195	rval = 0;
	196	if (child->exit_state == EXIT_ZOMBIE) /* already dead */
	197	break;
	198	child->exit_code = SIGKILL;
	199	wake_up_process(child);
	200	break;
	201
	202	case PTRACE_DETACH: /* detach a process that was attached. */
	203	set_single_step (child, 0); /* Clear single-step flag */
	204	rval = ptrace_detach(child, data);
	205	break;
	206
	207	default:
	208	rval = -EIO;
	209	goto out;
	210	}
481bed45	211	out:
1da177e4 LT	212	return rval;
	213	}
	214
	215	asmlinkage void syscall_trace(void)
	216	{
	217	if (!test_thread_flag(TIF_SYSCALL_TRACE))
	218	return;
	219	if (!(current->ptrace & PT_PTRACED))
	220	return;
	221	/* The 0x80 provides a way for the tracing parent to distinguish
	222	between a syscall stop and SIGTRAP delivery */
	223	ptrace_notify(SIGTRAP \| ((current->ptrace & PT_TRACESYSGOOD)
	224	? 0x80 : 0));
	225	/*
	226	* this isn't the same as continuing with a signal, but it will do
	227	* for normal use. strace only continues with a signal if the
	228	* stopping signal is not SIGTRAP. -brl
	229	*/
	230	if (current->exit_code) {
	231	send_sig(current->exit_code, current, 1);
	232	current->exit_code = 0;
	233	}
	234	}
	235
	236	void ptrace_disable (struct task_struct *child)
	237	{
	238	/* nothing to do */
	239	}