arch/avr32/kernel/ptrace.c - maze/linux - Git at Google

 /*
  * Copyright (C) 2004-2006 Atmel Corporation
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */
 #undef DEBUG
 #include <linux/kernel.h>
 #include <linux/sched.h>
 #include <linux/mm.h>
 #include <linux/ptrace.h>
 #include <linux/errno.h>
 #include <linux/user.h>
 #include <linux/security.h>
 #include <linux/unistd.h>
 #include <linux/notifier.h>

 #include <asm/traps.h>
 #include <asm/uaccess.h>
 #include <asm/ocd.h>
 #include <asm/mmu_context.h>
 #include <linux/kdebug.h>

 static struct pt_regs *get_user_regs(struct task_struct *tsk)
 {
 	return (struct pt_regs *)((unsigned long)task_stack_page(tsk) +
 				  THREAD_SIZE - sizeof(struct pt_regs));
 }

 static void ptrace_single_step(struct task_struct *tsk)
 {
 	pr_debug("ptrace_single_step: pid=%u, SR=0x%08lx\n",
 		 tsk->pid, tsk->thread.cpu_context.sr);
 	if (!(tsk->thread.cpu_context.sr & SR_D)) {
 		/*
 		 * Set a breakpoint at the current pc to force the
 		 * process into debug mode.  The syscall/exception
 		 * exit code will set a breakpoint at the return
 		 * address when this flag is set.
 		 */
 		pr_debug("ptrace_single_step: Setting TIF_BREAKPOINT\n");
 		set_tsk_thread_flag(tsk, TIF_BREAKPOINT);
 	}

 	/* The monitor code will do the actual step for us */
 	set_tsk_thread_flag(tsk, TIF_SINGLE_STEP);
 }

 /*
  * Called by kernel/ptrace.c when detaching
  *
  * Make sure any single step bits, etc. are not set
  */
 void ptrace_disable(struct task_struct *child)
 {
 	clear_tsk_thread_flag(child, TIF_SINGLE_STEP);
 }

 /*
  * Handle hitting a breakpoint
  */
 static void ptrace_break(struct task_struct *tsk, struct pt_regs *regs)
 {
 	siginfo_t info;

 	info.si_signo = SIGTRAP;
 	info.si_errno = 0;
 	info.si_code  = TRAP_BRKPT;
 	info.si_addr  = (void __user *)instruction_pointer(regs);

 	pr_debug("ptrace_break: Sending SIGTRAP to PID %u (pc = 0x%p)\n",
 		 tsk->pid, info.si_addr);
 	force_sig_info(SIGTRAP, &info, tsk);
 }

 /*
  * Read the word at offset "offset" into the task's "struct user". We
  * actually access the pt_regs struct stored on the kernel stack.
  */
 static int ptrace_read_user(struct task_struct *tsk, unsigned long offset,
 			    unsigned long __user *data)
 {
 	unsigned long *regs;
 	unsigned long value;

 	pr_debug("ptrace_read_user(%p, %#lx, %p)\n",
 		 tsk, offset, data);

 	if (offset & 3 || offset >= sizeof(struct user)) {
 		printk("ptrace_read_user: invalid offset 0x%08lx\n", offset);
 		return -EIO;
 	}

 	regs = (unsigned long *)get_user_regs(tsk);

 	value = 0;
 	if (offset < sizeof(struct pt_regs))
 		value = regs[offset / sizeof(regs[0])];

 	return put_user(value, data);
 }

 /*
  * Write the word "value" to offset "offset" into the task's "struct
  * user". We actually access the pt_regs struct stored on the kernel
  * stack.
  */
 static int ptrace_write_user(struct task_struct *tsk, unsigned long offset,
 			     unsigned long value)
 {
 	unsigned long *regs;

 	if (offset & 3 || offset >= sizeof(struct user)) {
 		printk("ptrace_write_user: invalid offset 0x%08lx\n", offset);
 		return -EIO;
 	}

 	if (offset >= sizeof(struct pt_regs))
 		return 0;

 	regs = (unsigned long *)get_user_regs(tsk);
 	regs[offset / sizeof(regs[0])] = value;

 	return 0;
 }

 static int ptrace_getregs(struct task_struct *tsk, void __user *uregs)
 {
 	struct pt_regs *regs = get_user_regs(tsk);

 	return copy_to_user(uregs, regs, sizeof(*regs)) ? -EFAULT : 0;
 }

 static int ptrace_setregs(struct task_struct *tsk, const void __user *uregs)
 {
 	struct pt_regs newregs;
 	int ret;

 	ret = -EFAULT;
 	if (copy_from_user(&newregs, uregs, sizeof(newregs)) == 0) {
 		struct pt_regs *regs = get_user_regs(tsk);

 		ret = -EINVAL;
 		if (valid_user_regs(&newregs)) {
 			*regs = newregs;
 			ret = 0;
 		}
 	}

 	return ret;
 }

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

 	pr_debug("arch_ptrace(%ld, %d, %#lx, %#lx)\n",
 		 request, child->pid, addr, data);

 	pr_debug("ptrace: Enabling monitor mode...\n");
 	__mtdr(DBGREG_DC, __mfdr(DBGREG_DC) | DC_MM | DC_DBE);

 	switch (request) {
 	/* Read the word at location addr in the child process */
 	case PTRACE_PEEKTEXT:
 	case PTRACE_PEEKDATA:
 		ret = generic_ptrace_peekdata(child, addr, data);
 		break;

 	case PTRACE_PEEKUSR:
 		ret = ptrace_read_user(child, addr,
 				       (unsigned long __user *)data);
 		break;

 	/* Write the word in data at location addr */
 	case PTRACE_POKETEXT:
 	case PTRACE_POKEDATA:
 		ret = generic_ptrace_pokedata(child, addr, data);
 		break;

 	case PTRACE_POKEUSR:
 		ret = ptrace_write_user(child, addr, data);
 		break;

 	/* continue and stop at next (return from) syscall */
 	case PTRACE_SYSCALL:
 	/* restart after signal */
 	case PTRACE_CONT:
 		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;
 		/* XXX: Are we sure no breakpoints are active here? */
 		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)
 			break;
 		child->exit_code = SIGKILL;
 		wake_up_process(child);
 		break;

 	/*
 	 * execute single instruction.
 	 */
 	case PTRACE_SINGLESTEP:
 		ret = -EIO;
 		if (!valid_signal(data))
 			break;
 		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 		ptrace_single_step(child);
 		child->exit_code = data;
 		wake_up_process(child);
 		ret = 0;
 		break;

 	/* Detach a process that was attached */
 	case PTRACE_DETACH:
 		ret = ptrace_detach(child, data);
 		break;

 	case PTRACE_GETREGS:
 		ret = ptrace_getregs(child, (void __user *)data);
 		break;

 	case PTRACE_SETREGS:
 		ret = ptrace_setregs(child, (const void __user *)data);
 		break;

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

 	pr_debug("sys_ptrace returning %d (DC = 0x%08lx)\n", ret, __mfdr(DBGREG_DC));
 	return ret;
 }

 asmlinkage void syscall_trace(void)
 {
 	pr_debug("syscall_trace called\n");
 	if (!test_thread_flag(TIF_SYSCALL_TRACE))
 		return;
 	if (!(current->ptrace & PT_PTRACED))
 		return;

 	pr_debug("syscall_trace: notifying parent\n");
 	/* 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) {
 		pr_debug("syscall_trace: sending signal %d to PID %u\n",
 			 current->exit_code, current->pid);
 		send_sig(current->exit_code, current, 1);
 		current->exit_code = 0;
 	}
 }

 asmlinkage void do_debug_priv(struct pt_regs *regs)
 {
 	unsigned long dc, ds;
 	unsigned long die_val;

 	ds = __mfdr(DBGREG_DS);

 	pr_debug("do_debug_priv: pc = %08lx, ds = %08lx\n", regs->pc, ds);

 	if (ds & DS_SSS)
 		die_val = DIE_SSTEP;
 	else
 		die_val = DIE_BREAKPOINT;

 	if (notify_die(die_val, "ptrace", regs, 0, 0, SIGTRAP) == NOTIFY_STOP)
 		return;

 	if (likely(ds & DS_SSS)) {
 		extern void itlb_miss(void);
 		extern void tlb_miss_common(void);
 		struct thread_info *ti;

 		dc = __mfdr(DBGREG_DC);
 		dc &= ~DC_SS;
 		__mtdr(DBGREG_DC, dc);

 		ti = current_thread_info();
 		set_ti_thread_flag(ti, TIF_BREAKPOINT);

 		/* The TLB miss handlers don't check thread flags */
 		if ((regs->pc >= (unsigned long)&itlb_miss)
 		    && (regs->pc <= (unsigned long)&tlb_miss_common)) {
 			__mtdr(DBGREG_BWA2A, sysreg_read(RAR_EX));
 			__mtdr(DBGREG_BWC2A, 0x40000001 | (get_asid() << 1));
 		}

 		/*
 		 * If we're running in supervisor mode, the breakpoint
 		 * will take us where we want directly, no need to
 		 * single step.
 		 */
 		if ((regs->sr & MODE_MASK) != MODE_SUPERVISOR)
 			set_ti_thread_flag(ti, TIF_SINGLE_STEP);
 	} else {
 		panic("Unable to handle debug trap at pc = %08lx\n",
 		      regs->pc);
 	}
 }

 /*
  * Handle breakpoints, single steps and other debuggy things. To keep
  * things simple initially, we run with interrupts and exceptions
  * disabled all the time.
  */
 asmlinkage void do_debug(struct pt_regs *regs)
 {
 	unsigned long dc, ds;

 	ds = __mfdr(DBGREG_DS);
 	pr_debug("do_debug: pc = %08lx, ds = %08lx\n", regs->pc, ds);

 	if (test_thread_flag(TIF_BREAKPOINT)) {
 		pr_debug("TIF_BREAKPOINT set\n");
 		/* We're taking care of it */
 		clear_thread_flag(TIF_BREAKPOINT);
 		__mtdr(DBGREG_BWC2A, 0);
 	}

 	if (test_thread_flag(TIF_SINGLE_STEP)) {
 		pr_debug("TIF_SINGLE_STEP set, ds = 0x%08lx\n", ds);
 		if (ds & DS_SSS) {
 			dc = __mfdr(DBGREG_DC);
 			dc &= ~DC_SS;
 			__mtdr(DBGREG_DC, dc);

 			clear_thread_flag(TIF_SINGLE_STEP);
 			ptrace_break(current, regs);
 		}
 	} else {
 		/* regular breakpoint */
 		ptrace_break(current, regs);
 	}
 }
	/*
	* Copyright (C) 2004-2006 Atmel Corporation
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*/
	#undef DEBUG
	#include <linux/kernel.h>
	#include <linux/sched.h>
	#include <linux/mm.h>
	#include <linux/ptrace.h>
	#include <linux/errno.h>
	#include <linux/user.h>
	#include <linux/security.h>
	#include <linux/unistd.h>
	#include <linux/notifier.h>

	#include <asm/traps.h>
	#include <asm/uaccess.h>
	#include <asm/ocd.h>
	#include <asm/mmu_context.h>
	#include <linux/kdebug.h>

	static struct pt_regs get_user_regs(struct task_struct tsk)
	{
	return (struct pt_regs *)((unsigned long)task_stack_page(tsk) +
	THREAD_SIZE - sizeof(struct pt_regs));
	}

	static void ptrace_single_step(struct task_struct *tsk)
	{
	pr_debug("ptrace_single_step: pid=%u, SR=0x%08lx\n",
	tsk->pid, tsk->thread.cpu_context.sr);
	if (!(tsk->thread.cpu_context.sr & SR_D)) {
	/*
	* Set a breakpoint at the current pc to force the
	* process into debug mode. The syscall/exception
	* exit code will set a breakpoint at the return
	* address when this flag is set.
	*/
	pr_debug("ptrace_single_step: Setting TIF_BREAKPOINT\n");
	set_tsk_thread_flag(tsk, TIF_BREAKPOINT);
	}

	/* The monitor code will do the actual step for us */
	set_tsk_thread_flag(tsk, TIF_SINGLE_STEP);
	}

	/*
	* Called by kernel/ptrace.c when detaching
	*
	* Make sure any single step bits, etc. are not set
	*/
	void ptrace_disable(struct task_struct *child)
	{
	clear_tsk_thread_flag(child, TIF_SINGLE_STEP);
	}

	/*
	* Handle hitting a breakpoint
	*/
	static void ptrace_break(struct task_struct tsk, struct pt_regs regs)
	{
	siginfo_t info;

	info.si_signo = SIGTRAP;
	info.si_errno = 0;
	info.si_code = TRAP_BRKPT;
	info.si_addr = (void __user *)instruction_pointer(regs);

	pr_debug("ptrace_break: Sending SIGTRAP to PID %u (pc = 0x%p)\n",
	tsk->pid, info.si_addr);
	force_sig_info(SIGTRAP, &info, tsk);
	}

	/*
	* Read the word at offset "offset" into the task's "struct user". We
	* actually access the pt_regs struct stored on the kernel stack.
	*/
	static int ptrace_read_user(struct task_struct *tsk, unsigned long offset,
	unsigned long __user *data)
	{
	unsigned long *regs;
	unsigned long value;

	pr_debug("ptrace_read_user(%p, %#lx, %p)\n",
	tsk, offset, data);

	if (offset & 3 \|\| offset >= sizeof(struct user)) {
	printk("ptrace_read_user: invalid offset 0x%08lx\n", offset);
	return -EIO;
	}

	regs = (unsigned long *)get_user_regs(tsk);

	value = 0;
	if (offset < sizeof(struct pt_regs))
	value = regs[offset / sizeof(regs[0])];

	return put_user(value, data);
	}

	/*
	* Write the word "value" to offset "offset" into the task's "struct
	* user". We actually access the pt_regs struct stored on the kernel
	* stack.
	*/
	static int ptrace_write_user(struct task_struct *tsk, unsigned long offset,
	unsigned long value)
	{
	unsigned long *regs;

	if (offset & 3 \|\| offset >= sizeof(struct user)) {
	printk("ptrace_write_user: invalid offset 0x%08lx\n", offset);
	return -EIO;
	}

	if (offset >= sizeof(struct pt_regs))
	return 0;

	regs = (unsigned long *)get_user_regs(tsk);
	regs[offset / sizeof(regs[0])] = value;

	return 0;
	}

	static int ptrace_getregs(struct task_struct tsk, void __user uregs)
	{
	struct pt_regs *regs = get_user_regs(tsk);

	return copy_to_user(uregs, regs, sizeof(*regs)) ? -EFAULT : 0;
	}

	static int ptrace_setregs(struct task_struct tsk, const void __user uregs)
	{
	struct pt_regs newregs;
	int ret;

	ret = -EFAULT;
	if (copy_from_user(&newregs, uregs, sizeof(newregs)) == 0) {
	struct pt_regs *regs = get_user_regs(tsk);

	ret = -EINVAL;
	if (valid_user_regs(&newregs)) {
	*regs = newregs;
	ret = 0;
	}
	}

	return ret;
	}

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

	pr_debug("arch_ptrace(%ld, %d, %#lx, %#lx)\n",
	request, child->pid, addr, data);

	pr_debug("ptrace: Enabling monitor mode...\n");
	__mtdr(DBGREG_DC, __mfdr(DBGREG_DC) \| DC_MM \| DC_DBE);

	switch (request) {
	/* Read the word at location addr in the child process */
	case PTRACE_PEEKTEXT:
	case PTRACE_PEEKDATA:
	ret = generic_ptrace_peekdata(child, addr, data);
	break;

	case PTRACE_PEEKUSR:
	ret = ptrace_read_user(child, addr,
	(unsigned long __user *)data);
	break;

	/* Write the word in data at location addr */
	case PTRACE_POKETEXT:
	case PTRACE_POKEDATA:
	ret = generic_ptrace_pokedata(child, addr, data);
	break;

	case PTRACE_POKEUSR:
	ret = ptrace_write_user(child, addr, data);
	break;

	/* continue and stop at next (return from) syscall */
	case PTRACE_SYSCALL:
	/* restart after signal */
	case PTRACE_CONT:
	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;
	/* XXX: Are we sure no breakpoints are active here? */
	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)
	break;
	child->exit_code = SIGKILL;
	wake_up_process(child);
	break;

	/*
	* execute single instruction.
	*/
	case PTRACE_SINGLESTEP:
	ret = -EIO;
	if (!valid_signal(data))
	break;
	clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
	ptrace_single_step(child);
	child->exit_code = data;
	wake_up_process(child);
	ret = 0;
	break;

	/* Detach a process that was attached */
	case PTRACE_DETACH:
	ret = ptrace_detach(child, data);
	break;

	case PTRACE_GETREGS:
	ret = ptrace_getregs(child, (void __user *)data);
	break;

	case PTRACE_SETREGS:
	ret = ptrace_setregs(child, (const void __user *)data);
	break;

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

	pr_debug("sys_ptrace returning %d (DC = 0x%08lx)\n", ret, __mfdr(DBGREG_DC));
	return ret;
	}

	asmlinkage void syscall_trace(void)
	{
	pr_debug("syscall_trace called\n");
	if (!test_thread_flag(TIF_SYSCALL_TRACE))
	return;
	if (!(current->ptrace & PT_PTRACED))
	return;

	pr_debug("syscall_trace: notifying parent\n");
	/* 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) {
	pr_debug("syscall_trace: sending signal %d to PID %u\n",
	current->exit_code, current->pid);
	send_sig(current->exit_code, current, 1);
	current->exit_code = 0;
	}
	}

	asmlinkage void do_debug_priv(struct pt_regs *regs)
	{
	unsigned long dc, ds;
	unsigned long die_val;

	ds = __mfdr(DBGREG_DS);

	pr_debug("do_debug_priv: pc = %08lx, ds = %08lx\n", regs->pc, ds);

	if (ds & DS_SSS)
	die_val = DIE_SSTEP;
	else
	die_val = DIE_BREAKPOINT;

	if (notify_die(die_val, "ptrace", regs, 0, 0, SIGTRAP) == NOTIFY_STOP)
	return;

	if (likely(ds & DS_SSS)) {
	extern void itlb_miss(void);
	extern void tlb_miss_common(void);
	struct thread_info *ti;

	dc = __mfdr(DBGREG_DC);
	dc &= ~DC_SS;
	__mtdr(DBGREG_DC, dc);

	ti = current_thread_info();
	set_ti_thread_flag(ti, TIF_BREAKPOINT);

	/* The TLB miss handlers don't check thread flags */
	if ((regs->pc >= (unsigned long)&itlb_miss)
	&& (regs->pc <= (unsigned long)&tlb_miss_common)) {
	__mtdr(DBGREG_BWA2A, sysreg_read(RAR_EX));
	__mtdr(DBGREG_BWC2A, 0x40000001 \| (get_asid() << 1));
	}

	/*
	* If we're running in supervisor mode, the breakpoint
	* will take us where we want directly, no need to
	* single step.
	*/
	if ((regs->sr & MODE_MASK) != MODE_SUPERVISOR)
	set_ti_thread_flag(ti, TIF_SINGLE_STEP);
	} else {
	panic("Unable to handle debug trap at pc = %08lx\n",
	regs->pc);
	}
	}

	/*
	* Handle breakpoints, single steps and other debuggy things. To keep
	* things simple initially, we run with interrupts and exceptions
	* disabled all the time.
	*/
	asmlinkage void do_debug(struct pt_regs *regs)
	{
	unsigned long dc, ds;

	ds = __mfdr(DBGREG_DS);
	pr_debug("do_debug: pc = %08lx, ds = %08lx\n", regs->pc, ds);

	if (test_thread_flag(TIF_BREAKPOINT)) {
	pr_debug("TIF_BREAKPOINT set\n");
	/* We're taking care of it */
	clear_thread_flag(TIF_BREAKPOINT);
	__mtdr(DBGREG_BWC2A, 0);
	}

	if (test_thread_flag(TIF_SINGLE_STEP)) {
	pr_debug("TIF_SINGLE_STEP set, ds = 0x%08lx\n", ds);
	if (ds & DS_SSS) {
	dc = __mfdr(DBGREG_DC);
	dc &= ~DC_SS;
	__mtdr(DBGREG_DC, dc);

	clear_thread_flag(TIF_SINGLE_STEP);
	ptrace_break(current, regs);
	}
	} else {
	/* regular breakpoint */
	ptrace_break(current, regs);
	}
	}