arch/v850/kernel/ptrace.c - maze/linux - Git at Google

 /*
  * 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 = generic_ptrace_pokedata(child, addr, data);
 		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 */
 }
	/*
	* 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 = generic_ptrace_pokedata(child, addr, data);
	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 */
	}