arch/sh/kernel/ptrace_64.c - linux - Git at Google

 /*
  * 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.
  *
  * arch/sh64/kernel/ptrace.c
  *
  * Copyright (C) 2000, 2001  Paolo Alberelli
  * Copyright (C) 2003  Paul Mundt
  *
  * Started from SH3/4 version:
  *   SuperH version:   Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
  *
  *   Original x86 implementation:
  *	By Ross Biro 1/23/92
  *	edited by Linus Torvalds
  *
  */

 #include <linux/kernel.h>
 #include <linux/rwsem.h>
 #include <linux/sched.h>
 #include <linux/mm.h>
 #include <linux/smp.h>
 #include <linux/smp_lock.h>
 #include <linux/errno.h>
 #include <linux/ptrace.h>
 #include <linux/user.h>
 #include <linux/signal.h>
 #include <linux/syscalls.h>

 #include <asm/io.h>
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
 #include <asm/system.h>
 #include <asm/processor.h>
 #include <asm/mmu_context.h>

 /* This mask defines the bits of the SR which the user is not allowed to
    change, which are everything except S, Q, M, PR, SZ, FR. */
 #define SR_MASK      (0xffff8cfd)

 /*
  * does not yet catch signals sent when the child dies.
  * in exit.c or in signal.c.
  */

 /*
  * This routine will get a word from the user area in the process kernel stack.
  */
 static inline int get_stack_long(struct task_struct *task, int offset)
 {
 	unsigned char *stack;

 	stack = (unsigned char *)(task->thread.uregs);
 	stack += offset;
 	return (*((int *)stack));
 }

 static inline unsigned long
 get_fpu_long(struct task_struct *task, unsigned long addr)
 {
 	unsigned long tmp;
 	struct pt_regs *regs;
 	regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;

 	if (!tsk_used_math(task)) {
 		if (addr == offsetof(struct user_fpu_struct, fpscr)) {
 			tmp = FPSCR_INIT;
 		} else {
 			tmp = 0xffffffffUL; /* matches initial value in fpu.c */
 		}
 		return tmp;
 	}

 	if (last_task_used_math == task) {
 		enable_fpu();
 		save_fpu(task, regs);
 		disable_fpu();
 		last_task_used_math = 0;
 		regs->sr |= SR_FD;
 	}

 	tmp = ((long *)&task->thread.fpu)[addr / sizeof(unsigned long)];
 	return tmp;
 }

 /*
  * This routine will put a word into the user area in the process kernel stack.
  */
 static inline int put_stack_long(struct task_struct *task, int offset,
 				 unsigned long data)
 {
 	unsigned char *stack;

 	stack = (unsigned char *)(task->thread.uregs);
 	stack += offset;
 	*(unsigned long *) stack = data;
 	return 0;
 }

 static inline int
 put_fpu_long(struct task_struct *task, unsigned long addr, unsigned long data)
 {
 	struct pt_regs *regs;

 	regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;

 	if (!tsk_used_math(task)) {
 		fpinit(&task->thread.fpu.hard);
 		set_stopped_child_used_math(task);
 	} else if (last_task_used_math == task) {
 		enable_fpu();
 		save_fpu(task, regs);
 		disable_fpu();
 		last_task_used_math = 0;
 		regs->sr |= SR_FD;
 	}

 	((long *)&task->thread.fpu)[addr / sizeof(unsigned long)] = data;
 	return 0;
 }


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

 	switch (request) {
 	/* when I and D space are separate, these will need to be fixed. */
 	case PTRACE_PEEKTEXT: /* read word at location addr. */
 	case PTRACE_PEEKDATA:
 		ret = generic_ptrace_peekdata(child, addr, data);
 		break;

 	/* read the word at location addr in the USER area. */
 	case PTRACE_PEEKUSR: {
 		unsigned long tmp;

 		ret = -EIO;
 		if ((addr & 3) || addr < 0)
 			break;

 		if (addr < sizeof(struct pt_regs))
 			tmp = get_stack_long(child, addr);
 		else if ((addr >= offsetof(struct user, fpu)) &&
 			 (addr <  offsetof(struct user, u_fpvalid))) {
 			tmp = get_fpu_long(child, addr - offsetof(struct user, fpu));
 		} else if (addr == offsetof(struct user, u_fpvalid)) {
 			tmp = !!tsk_used_math(child);
 		} else {
 			break;
 		}
 		ret = put_user(tmp, (unsigned long *)data);
 		break;
 	}

 	/* when I and D space are separate, this will have to be fixed. */
 	case PTRACE_POKETEXT: /* write the word at location addr. */
 	case PTRACE_POKEDATA:
 		ret = generic_ptrace_pokedata(child, addr, data);
 		break;

 	case PTRACE_POKEUSR:
                 /* write the word at location addr in the USER area. We must
                    disallow any changes to certain SR bits or u_fpvalid, since
                    this could crash the kernel or result in a security
                    loophole. */
 		ret = -EIO;
 		if ((addr & 3) || addr < 0)
 			break;

 		if (addr < sizeof(struct pt_regs)) {
 			/* Ignore change of top 32 bits of SR */
 			if (addr == offsetof (struct pt_regs, sr)+4)
 			{
 				ret = 0;
 				break;
 			}
 			/* If lower 32 bits of SR, ignore non-user bits */
 			if (addr == offsetof (struct pt_regs, sr))
 			{
 				long cursr = get_stack_long(child, addr);
 				data &= ~(SR_MASK);
 				data |= (cursr & SR_MASK);
 			}
 			ret = put_stack_long(child, addr, data);
 		}
 		else if ((addr >= offsetof(struct user, fpu)) &&
 			 (addr <  offsetof(struct user, u_fpvalid))) {
 			ret = put_fpu_long(child, addr - offsetof(struct user, fpu), data);
 		}
 		break;

 	case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 	case PTRACE_CONT: { /* restart after signal. */
 		ret = -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;
 		wake_up_process(child);
 		ret = 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: {
 		ret = 0;
 		if (child->exit_state == EXIT_ZOMBIE)	/* already dead */
 			break;
 		child->exit_code = SIGKILL;
 		wake_up_process(child);
 		break;
 	}

 	case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 		struct pt_regs *regs;

 		ret = -EIO;
 		if (!valid_signal(data))
 			break;
 		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 		if ((child->ptrace & PT_DTRACE) == 0) {
 			/* Spurious delayed TF traps may occur */
 			child->ptrace |= PT_DTRACE;
 		}

 		regs = child->thread.uregs;

 		regs->sr |= SR_SSTEP;	/* auto-resetting upon exception */

 		child->exit_code = data;
 		/* give it a chance to run. */
 		wake_up_process(child);
 		ret = 0;
 		break;
 	}

 	default:
 		ret = ptrace_request(child, request, addr, data);
 		break;
 	}
 	return ret;
 }

 asmlinkage int sh64_ptrace(long request, long pid, long addr, long data)
 {
 #define WPC_DBRMODE 0x0d104008
 	static int first_call = 1;

 	lock_kernel();
 	if (first_call) {
 		/* Set WPC.DBRMODE to 0.  This makes all debug events get
 		 * delivered through RESVEC, i.e. into the handlers in entry.S.
 		 * (If the kernel was downloaded using a remote gdb, WPC.DBRMODE
 		 * would normally be left set to 1, which makes debug events get
 		 * delivered through DBRVEC, i.e. into the remote gdb's
 		 * handlers.  This prevents ptrace getting them, and confuses
 		 * the remote gdb.) */
 		printk("DBRMODE set to 0 to permit native debugging\n");
 		poke_real_address_q(WPC_DBRMODE, 0);
 		first_call = 0;
 	}
 	unlock_kernel();

 	return sys_ptrace(request, pid, addr, data);
 }

 asmlinkage void syscall_trace(void)
 {
 	struct task_struct *tsk = current;

 	if (!test_thread_flag(TIF_SYSCALL_TRACE))
 		return;
 	if (!(tsk->ptrace & PT_PTRACED))
 		return;

 	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 (tsk->exit_code) {
 		send_sig(tsk->exit_code, tsk, 1);
 		tsk->exit_code = 0;
 	}
 }

 /* Called with interrupts disabled */
 asmlinkage void do_single_step(unsigned long long vec, struct pt_regs *regs)
 {
 	/* This is called after a single step exception (DEBUGSS).
 	   There is no need to change the PC, as it is a post-execution
 	   exception, as entry.S does not do anything to the PC for DEBUGSS.
 	   We need to clear the Single Step setting in SR to avoid
 	   continually stepping. */
 	local_irq_enable();
 	regs->sr &= ~SR_SSTEP;
 	force_sig(SIGTRAP, current);
 }

 /* Called with interrupts disabled */
 asmlinkage void do_software_break_point(unsigned long long vec,
 					struct pt_regs *regs)
 {
 	/* We need to forward step the PC, to counteract the backstep done
 	   in signal.c. */
 	local_irq_enable();
 	force_sig(SIGTRAP, current);
 	regs->pc += 4;
 }

 /*
  * Called by kernel/ptrace.c when detaching..
  *
  * Make sure single step bits etc are not set.
  */
 void ptrace_disable(struct task_struct *child)
 {
         /* nothing to do.. */
 }
	/*
	* 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.
	*
	* arch/sh64/kernel/ptrace.c
	*
	* Copyright (C) 2000, 2001 Paolo Alberelli
	* Copyright (C) 2003 Paul Mundt
	*
	* Started from SH3/4 version:
	* SuperH version: Copyright (C) 1999, 2000 Kaz Kojima & Niibe Yutaka
	*
	* Original x86 implementation:
	* By Ross Biro 1/23/92
	* edited by Linus Torvalds
	*
	*/

	#include <linux/kernel.h>
	#include <linux/rwsem.h>
	#include <linux/sched.h>
	#include <linux/mm.h>
	#include <linux/smp.h>
	#include <linux/smp_lock.h>
	#include <linux/errno.h>
	#include <linux/ptrace.h>
	#include <linux/user.h>
	#include <linux/signal.h>
	#include <linux/syscalls.h>

	#include <asm/io.h>
	#include <asm/uaccess.h>
	#include <asm/pgtable.h>
	#include <asm/system.h>
	#include <asm/processor.h>
	#include <asm/mmu_context.h>

	/* This mask defines the bits of the SR which the user is not allowed to
	change, which are everything except S, Q, M, PR, SZ, FR. */
	#define SR_MASK (0xffff8cfd)

	/*
	* does not yet catch signals sent when the child dies.
	* in exit.c or in signal.c.
	*/

	/*
	* This routine will get a word from the user area in the process kernel stack.
	*/
	static inline int get_stack_long(struct task_struct *task, int offset)
	{
	unsigned char *stack;

	stack = (unsigned char *)(task->thread.uregs);
	stack += offset;
	return (((int )stack));
	}

	static inline unsigned long
	get_fpu_long(struct task_struct *task, unsigned long addr)
	{
	unsigned long tmp;
	struct pt_regs *regs;
	regs = (struct pt_regs)((unsigned char )task + THREAD_SIZE) - 1;

	if (!tsk_used_math(task)) {
	if (addr == offsetof(struct user_fpu_struct, fpscr)) {
	tmp = FPSCR_INIT;
	} else {
	tmp = 0xffffffffUL; /* matches initial value in fpu.c */
	}
	return tmp;
	}

	if (last_task_used_math == task) {
	enable_fpu();
	save_fpu(task, regs);
	disable_fpu();
	last_task_used_math = 0;
	regs->sr \|= SR_FD;
	}

	tmp = ((long *)&task->thread.fpu)[addr / sizeof(unsigned long)];
	return tmp;
	}

	/*
	* This routine will put a word into the user area in the process kernel stack.
	*/
	static inline int put_stack_long(struct task_struct *task, int offset,
	unsigned long data)
	{
	unsigned char *stack;

	stack = (unsigned char *)(task->thread.uregs);
	stack += offset;
	(unsigned long ) stack = data;
	return 0;
	}

	static inline int
	put_fpu_long(struct task_struct *task, unsigned long addr, unsigned long data)
	{
	struct pt_regs *regs;

	regs = (struct pt_regs)((unsigned char )task + THREAD_SIZE) - 1;

	if (!tsk_used_math(task)) {
	fpinit(&task->thread.fpu.hard);
	set_stopped_child_used_math(task);
	} else if (last_task_used_math == task) {
	enable_fpu();
	save_fpu(task, regs);
	disable_fpu();
	last_task_used_math = 0;
	regs->sr \|= SR_FD;
	}

	((long *)&task->thread.fpu)[addr / sizeof(unsigned long)] = data;
	return 0;
	}


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

	switch (request) {
	/* when I and D space are separate, these will need to be fixed. */
	case PTRACE_PEEKTEXT: /* read word at location addr. */
	case PTRACE_PEEKDATA:
	ret = generic_ptrace_peekdata(child, addr, data);
	break;

	/* read the word at location addr in the USER area. */
	case PTRACE_PEEKUSR: {
	unsigned long tmp;

	ret = -EIO;
	if ((addr & 3) \|\| addr < 0)
	break;

	if (addr < sizeof(struct pt_regs))
	tmp = get_stack_long(child, addr);
	else if ((addr >= offsetof(struct user, fpu)) &&
	(addr < offsetof(struct user, u_fpvalid))) {
	tmp = get_fpu_long(child, addr - offsetof(struct user, fpu));
	} else if (addr == offsetof(struct user, u_fpvalid)) {
	tmp = !!tsk_used_math(child);
	} else {
	break;
	}
	ret = put_user(tmp, (unsigned long *)data);
	break;
	}

	/* when I and D space are separate, this will have to be fixed. */
	case PTRACE_POKETEXT: /* write the word at location addr. */
	case PTRACE_POKEDATA:
	ret = generic_ptrace_pokedata(child, addr, data);
	break;

	case PTRACE_POKEUSR:
	/* write the word at location addr in the USER area. We must
	disallow any changes to certain SR bits or u_fpvalid, since
	this could crash the kernel or result in a security
	loophole. */
	ret = -EIO;
	if ((addr & 3) \|\| addr < 0)
	break;

	if (addr < sizeof(struct pt_regs)) {
	/* Ignore change of top 32 bits of SR */
	if (addr == offsetof (struct pt_regs, sr)+4)
	{
	ret = 0;
	break;
	}
	/* If lower 32 bits of SR, ignore non-user bits */
	if (addr == offsetof (struct pt_regs, sr))
	{
	long cursr = get_stack_long(child, addr);
	data &= ~(SR_MASK);
	data \|= (cursr & SR_MASK);
	}
	ret = put_stack_long(child, addr, data);
	}
	else if ((addr >= offsetof(struct user, fpu)) &&
	(addr < offsetof(struct user, u_fpvalid))) {
	ret = put_fpu_long(child, addr - offsetof(struct user, fpu), data);
	}
	break;

	case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
	case PTRACE_CONT: { /* restart after signal. */
	ret = -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;
	wake_up_process(child);
	ret = 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: {
	ret = 0;
	if (child->exit_state == EXIT_ZOMBIE) /* already dead */
	break;
	child->exit_code = SIGKILL;
	wake_up_process(child);
	break;
	}

	case PTRACE_SINGLESTEP: { /* set the trap flag. */
	struct pt_regs *regs;

	ret = -EIO;
	if (!valid_signal(data))
	break;
	clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
	if ((child->ptrace & PT_DTRACE) == 0) {
	/* Spurious delayed TF traps may occur */
	child->ptrace \|= PT_DTRACE;
	}

	regs = child->thread.uregs;

	regs->sr \|= SR_SSTEP; /* auto-resetting upon exception */

	child->exit_code = data;
	/* give it a chance to run. */
	wake_up_process(child);
	ret = 0;
	break;
	}

	default:
	ret = ptrace_request(child, request, addr, data);
	break;
	}
	return ret;
	}

	asmlinkage int sh64_ptrace(long request, long pid, long addr, long data)
	{
	#define WPC_DBRMODE 0x0d104008
	static int first_call = 1;

	lock_kernel();
	if (first_call) {
	/* Set WPC.DBRMODE to 0. This makes all debug events get
	* delivered through RESVEC, i.e. into the handlers in entry.S.
	* (If the kernel was downloaded using a remote gdb, WPC.DBRMODE
	* would normally be left set to 1, which makes debug events get
	* delivered through DBRVEC, i.e. into the remote gdb's
	* handlers. This prevents ptrace getting them, and confuses
	* the remote gdb.) */
	printk("DBRMODE set to 0 to permit native debugging\n");
	poke_real_address_q(WPC_DBRMODE, 0);
	first_call = 0;
	}
	unlock_kernel();

	return sys_ptrace(request, pid, addr, data);
	}

	asmlinkage void syscall_trace(void)
	{
	struct task_struct *tsk = current;

	if (!test_thread_flag(TIF_SYSCALL_TRACE))
	return;
	if (!(tsk->ptrace & PT_PTRACED))
	return;

	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 (tsk->exit_code) {
	send_sig(tsk->exit_code, tsk, 1);
	tsk->exit_code = 0;
	}
	}

	/* Called with interrupts disabled */
	asmlinkage void do_single_step(unsigned long long vec, struct pt_regs *regs)
	{
	/* This is called after a single step exception (DEBUGSS).
	There is no need to change the PC, as it is a post-execution
	exception, as entry.S does not do anything to the PC for DEBUGSS.
	We need to clear the Single Step setting in SR to avoid
	continually stepping. */
	local_irq_enable();
	regs->sr &= ~SR_SSTEP;
	force_sig(SIGTRAP, current);
	}

	/* Called with interrupts disabled */
	asmlinkage void do_software_break_point(unsigned long long vec,
	struct pt_regs *regs)
	{
	/* We need to forward step the PC, to counteract the backstep done
	in signal.c. */
	local_irq_enable();
	force_sig(SIGTRAP, current);
	regs->pc += 4;
	}

	/*
	* Called by kernel/ptrace.c when detaching..
	*
	* Make sure single step bits etc are not set.
	*/
	void ptrace_disable(struct task_struct *child)
	{
	/* nothing to do.. */
	}