[deliverable/linux.git] / include / linux / ptrace.h

#ifndef _LINUX_PTRACE_H
#define _LINUX_PTRACE_H
/* ptrace.h */
/* structs and defines to help the user use the ptrace system call. */

/* has the defines to get at the registers. */

#define PTRACE_TRACEME		   0
#define PTRACE_PEEKTEXT		   1
#define PTRACE_PEEKDATA		   2
#define PTRACE_PEEKUSR		   3
#define PTRACE_POKETEXT		   4
#define PTRACE_POKEDATA		   5
#define PTRACE_POKEUSR		   6
#define PTRACE_CONT		   7
#define PTRACE_KILL		   8
#define PTRACE_SINGLESTEP	   9

#define PTRACE_ATTACH		  16
#define PTRACE_DETACH		  17

#define PTRACE_SYSCALL		  24

/* 0x4200-0x4300 are reserved for architecture-independent additions.  */
#define PTRACE_SETOPTIONS	0x4200
#define PTRACE_GETEVENTMSG	0x4201
#define PTRACE_GETSIGINFO	0x4202
#define PTRACE_SETSIGINFO	0x4203

/*
 * Generic ptrace interface that exports the architecture specific regsets
 * using the corresponding NT_* types (which are also used in the core dump).
 * Please note that the NT_PRSTATUS note type in a core dump contains a full
 * 'struct elf_prstatus'. But the user_regset for NT_PRSTATUS contains just the
 * elf_gregset_t that is the pr_reg field of 'struct elf_prstatus'. For all the
 * other user_regset flavors, the user_regset layout and the ELF core dump note
 * payload are exactly the same layout.
 *
 * This interface usage is as follows:
 *	struct iovec iov = { buf, len};
 *
 *	ret = ptrace(PTRACE_GETREGSET/PTRACE_SETREGSET, pid, NT_XXX_TYPE, &iov);
 *
 * On the successful completion, iov.len will be updated by the kernel,
 * specifying how much the kernel has written/read to/from the user's iov.buf.
 */
#define PTRACE_GETREGSET	0x4204
#define PTRACE_SETREGSET	0x4205

#define PTRACE_SEIZE		0x4206
#define PTRACE_INTERRUPT	0x4207
#define PTRACE_LISTEN		0x4208

/* flags in @data for PTRACE_SEIZE */
#define PTRACE_SEIZE_DEVEL	0x80000000 /* temp flag for development */

/* options set using PTRACE_SETOPTIONS */
#define PTRACE_O_TRACESYSGOOD	0x00000001
#define PTRACE_O_TRACEFORK	0x00000002
#define PTRACE_O_TRACEVFORK	0x00000004
#define PTRACE_O_TRACECLONE	0x00000008
#define PTRACE_O_TRACEEXEC	0x00000010
#define PTRACE_O_TRACEVFORKDONE	0x00000020
#define PTRACE_O_TRACEEXIT	0x00000040

#define PTRACE_O_MASK		0x0000007f

/* Wait extended result codes for the above trace options.  */
#define PTRACE_EVENT_FORK	1
#define PTRACE_EVENT_VFORK	2
#define PTRACE_EVENT_CLONE	3
#define PTRACE_EVENT_EXEC	4
#define PTRACE_EVENT_VFORK_DONE	5
#define PTRACE_EVENT_EXIT	6
#define PTRACE_EVENT_STOP	7

#include <asm/ptrace.h>

#ifdef __KERNEL__
/*
 * Ptrace flags
 *
 * The owner ship rules for task->ptrace which holds the ptrace
 * flags is simple.  When a task is running it owns it's task->ptrace
 * flags.  When the a task is stopped the ptracer owns task->ptrace.
 */

#define PT_SEIZED	0x00010000	/* SEIZE used, enable new behavior */
#define PT_PTRACED	0x00000001
#define PT_DTRACE	0x00000002	/* delayed trace (used on m68k, i386) */
#define PT_TRACESYSGOOD	0x00000004
#define PT_PTRACE_CAP	0x00000008	/* ptracer can follow suid-exec */

/* PT_TRACE_* event enable flags */
#define PT_EVENT_FLAG_SHIFT	4
#define PT_EVENT_FLAG(event)	(1 << (PT_EVENT_FLAG_SHIFT + (event) - 1))

#define PT_TRACE_FORK		PT_EVENT_FLAG(PTRACE_EVENT_FORK)
#define PT_TRACE_VFORK		PT_EVENT_FLAG(PTRACE_EVENT_VFORK)
#define PT_TRACE_CLONE		PT_EVENT_FLAG(PTRACE_EVENT_CLONE)
#define PT_TRACE_EXEC		PT_EVENT_FLAG(PTRACE_EVENT_EXEC)
#define PT_TRACE_VFORK_DONE	PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE)
#define PT_TRACE_EXIT		PT_EVENT_FLAG(PTRACE_EVENT_EXIT)

#define PT_TRACE_MASK	0x000003f4

/* single stepping state bits (used on ARM and PA-RISC) */
#define PT_SINGLESTEP_BIT	31
#define PT_SINGLESTEP		(1<<PT_SINGLESTEP_BIT)
#define PT_BLOCKSTEP_BIT	30
#define PT_BLOCKSTEP		(1<<PT_BLOCKSTEP_BIT)

#include <linux/compiler.h>		/* For unlikely.  */
#include <linux/sched.h>		/* For struct task_struct.  */


extern long arch_ptrace(struct task_struct *child, long request,
			unsigned long addr, unsigned long data);
extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
extern void ptrace_disable(struct task_struct *);
extern int ptrace_check_attach(struct task_struct *task, bool ignore_state);
extern int ptrace_request(struct task_struct *child, long request,
			  unsigned long addr, unsigned long data);
extern void ptrace_notify(int exit_code);
extern void __ptrace_link(struct task_struct *child,
			  struct task_struct *new_parent);
extern void __ptrace_unlink(struct task_struct *child);
extern void exit_ptrace(struct task_struct *tracer);
#define PTRACE_MODE_READ   1
#define PTRACE_MODE_ATTACH 2
/* Returns 0 on success, -errno on denial. */
extern int __ptrace_may_access(struct task_struct *task, unsigned int mode);
/* Returns true on success, false on denial. */
extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);

static inline int ptrace_reparented(struct task_struct *child)
{
	return !same_thread_group(child->real_parent, child->parent);
}

static inline void ptrace_unlink(struct task_struct *child)
{
	if (unlikely(child->ptrace))
		__ptrace_unlink(child);
}

int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
			    unsigned long data);
int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
			    unsigned long data);

/**
 * ptrace_parent - return the task that is tracing the given task
 * @task: task to consider
 *
 * Returns %NULL if no one is tracing @task, or the &struct task_struct
 * pointer to its tracer.
 *
 * Must called under rcu_read_lock().  The pointer returned might be kept
 * live only by RCU.  During exec, this may be called with task_lock() held
 * on @task, still held from when check_unsafe_exec() was called.
 */
static inline struct task_struct *ptrace_parent(struct task_struct *task)
{
	if (unlikely(task->ptrace))
		return rcu_dereference(task->parent);
	return NULL;
}

/**
 * ptrace_event_enabled - test whether a ptrace event is enabled
 * @task: ptracee of interest
 * @event: %PTRACE_EVENT_* to test
 *
 * Test whether @event is enabled for ptracee @task.
 *
 * Returns %true if @event is enabled, %false otherwise.
 */
static inline bool ptrace_event_enabled(struct task_struct *task, int event)
{
	return task->ptrace & PT_EVENT_FLAG(event);
}

/**
 * ptrace_event - possibly stop for a ptrace event notification
 * @event:	%PTRACE_EVENT_* value to report
 * @message:	value for %PTRACE_GETEVENTMSG to return
 *
 * Check whether @event is enabled and, if so, report @event and @message
 * to the ptrace parent.
 *
 * Called without locks.
 */
static inline void ptrace_event(int event, unsigned long message)
{
	if (unlikely(ptrace_event_enabled(current, event))) {
		current->ptrace_message = message;
		ptrace_notify((event << 8) | SIGTRAP);
	} else if (event == PTRACE_EVENT_EXEC && unlikely(current->ptrace)) {
		/* legacy EXEC report via SIGTRAP */
		send_sig(SIGTRAP, current, 0);
	}
}

/**
 * ptrace_init_task - initialize ptrace state for a new child
 * @child:		new child task
 * @ptrace:		true if child should be ptrace'd by parent's tracer
 *
 * This is called immediately after adding @child to its parent's children
 * list.  @ptrace is false in the normal case, and true to ptrace @child.
 *
 * Called with current's siglock and write_lock_irq(&tasklist_lock) held.
 */
static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
{
	INIT_LIST_HEAD(&child->ptrace_entry);
	INIT_LIST_HEAD(&child->ptraced);
#ifdef CONFIG_HAVE_HW_BREAKPOINT
	atomic_set(&child->ptrace_bp_refcnt, 1);
#endif
	child->jobctl = 0;
	child->ptrace = 0;
	child->parent = child->real_parent;

	if (unlikely(ptrace) && current->ptrace) {
		child->ptrace = current->ptrace;
		__ptrace_link(child, current->parent);
	}
}

/**
 * ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
 * @task:	task in %EXIT_DEAD state
 *
 * Called with write_lock(&tasklist_lock) held.
 */
static inline void ptrace_release_task(struct task_struct *task)
{
	BUG_ON(!list_empty(&task->ptraced));
	ptrace_unlink(task);
	BUG_ON(!list_empty(&task->ptrace_entry));
}

#ifndef force_successful_syscall_return
/*
 * System call handlers that, upon successful completion, need to return a
 * negative value should call force_successful_syscall_return() right before
 * returning.  On architectures where the syscall convention provides for a
 * separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
 * others), this macro can be used to ensure that the error flag will not get
 * set.  On architectures which do not support a separate error flag, the macro
 * is a no-op and the spurious error condition needs to be filtered out by some
 * other means (e.g., in user-level, by passing an extra argument to the
 * syscall handler, or something along those lines).
 */
#define force_successful_syscall_return() do { } while (0)
#endif

/*
 * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
 *
 * These do-nothing inlines are used when the arch does not
 * implement single-step.  The kerneldoc comments are here
 * to document the interface for all arch definitions.
 */

#ifndef arch_has_single_step
/**
 * arch_has_single_step - does this CPU support user-mode single-step?
 *
 * If this is defined, then there must be function declarations or
 * inlines for user_enable_single_step() and user_disable_single_step().
 * arch_has_single_step() should evaluate to nonzero iff the machine
 * supports instruction single-step for user mode.
 * It can be a constant or it can test a CPU feature bit.
 */
#define arch_has_single_step()		(0)

/**
 * user_enable_single_step - single-step in user-mode task
 * @task: either current or a task stopped in %TASK_TRACED
 *
 * This can only be called when arch_has_single_step() has returned nonzero.
 * Set @task so that when it returns to user mode, it will trap after the
 * next single instruction executes.  If arch_has_block_step() is defined,
 * this must clear the effects of user_enable_block_step() too.
 */
static inline void user_enable_single_step(struct task_struct *task)
{
	BUG();			/* This can never be called.  */
}

/**
 * user_disable_single_step - cancel user-mode single-step
 * @task: either current or a task stopped in %TASK_TRACED
 *
 * Clear @task of the effects of user_enable_single_step() and
 * user_enable_block_step().  This can be called whether or not either
 * of those was ever called on @task, and even if arch_has_single_step()
 * returned zero.
 */
static inline void user_disable_single_step(struct task_struct *task)
{
}
#else
extern void user_enable_single_step(struct task_struct *);
extern void user_disable_single_step(struct task_struct *);
#endif	/* arch_has_single_step */

#ifndef arch_has_block_step
/**
 * arch_has_block_step - does this CPU support user-mode block-step?
 *
 * If this is defined, then there must be a function declaration or inline
 * for user_enable_block_step(), and arch_has_single_step() must be defined
 * too.  arch_has_block_step() should evaluate to nonzero iff the machine
 * supports step-until-branch for user mode.  It can be a constant or it
 * can test a CPU feature bit.
 */
#define arch_has_block_step()		(0)

/**
 * user_enable_block_step - step until branch in user-mode task
 * @task: either current or a task stopped in %TASK_TRACED
 *
 * This can only be called when arch_has_block_step() has returned nonzero,
 * and will never be called when single-instruction stepping is being used.
 * Set @task so that when it returns to user mode, it will trap after the
 * next branch or trap taken.
 */
static inline void user_enable_block_step(struct task_struct *task)
{
	BUG();			/* This can never be called.  */
}
#else
extern void user_enable_block_step(struct task_struct *);
#endif	/* arch_has_block_step */

#ifdef ARCH_HAS_USER_SINGLE_STEP_INFO
extern void user_single_step_siginfo(struct task_struct *tsk,
				struct pt_regs *regs, siginfo_t *info);
#else
static inline void user_single_step_siginfo(struct task_struct *tsk,
				struct pt_regs *regs, siginfo_t *info)
{
	memset(info, 0, sizeof(*info));
	info->si_signo = SIGTRAP;
}
#endif

#ifndef arch_ptrace_stop_needed
/**
 * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
 * @code:	current->exit_code value ptrace will stop with
 * @info:	siginfo_t pointer (or %NULL) for signal ptrace will stop with
 *
 * This is called with the siglock held, to decide whether or not it's
 * necessary to release the siglock and call arch_ptrace_stop() with the
 * same @code and @info arguments.  It can be defined to a constant if
 * arch_ptrace_stop() is never required, or always is.  On machines where
 * this makes sense, it should be defined to a quick test to optimize out
 * calling arch_ptrace_stop() when it would be superfluous.  For example,
 * if the thread has not been back to user mode since the last stop, the
 * thread state might indicate that nothing needs to be done.
 */
#define arch_ptrace_stop_needed(code, info)	(0)
#endif

#ifndef arch_ptrace_stop
/**
 * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
 * @code:	current->exit_code value ptrace will stop with
 * @info:	siginfo_t pointer (or %NULL) for signal ptrace will stop with
 *
 * This is called with no locks held when arch_ptrace_stop_needed() has
 * just returned nonzero.  It is allowed to block, e.g. for user memory
 * access.  The arch can have machine-specific work to be done before
 * ptrace stops.  On ia64, register backing store gets written back to user
 * memory here.  Since this can be costly (requires dropping the siglock),
 * we only do it when the arch requires it for this particular stop, as
 * indicated by arch_ptrace_stop_needed().
 */
#define arch_ptrace_stop(code, info)		do { } while (0)
#endif

extern int task_current_syscall(struct task_struct *target, long *callno,
				unsigned long args[6], unsigned int maxargs,
				unsigned long *sp, unsigned long *pc);

#ifdef CONFIG_HAVE_HW_BREAKPOINT
extern int ptrace_get_breakpoints(struct task_struct *tsk);
extern void ptrace_put_breakpoints(struct task_struct *tsk);
#else
static inline void ptrace_put_breakpoints(struct task_struct *tsk) { }
#endif /* CONFIG_HAVE_HW_BREAKPOINT */

#endif /* __KERNEL */

#endif
Commit	Line	Data
1da177e4 LT	1	#ifndef _LINUX_PTRACE_H
	2	#define _LINUX_PTRACE_H
	3	/* ptrace.h */
	4	/* structs and defines to help the user use the ptrace system call. */
	5
	6	/* has the defines to get at the registers. */
	7
	8	#define PTRACE_TRACEME 0
	9	#define PTRACE_PEEKTEXT 1
	10	#define PTRACE_PEEKDATA 2
	11	#define PTRACE_PEEKUSR 3
	12	#define PTRACE_POKETEXT 4
	13	#define PTRACE_POKEDATA 5
	14	#define PTRACE_POKEUSR 6
	15	#define PTRACE_CONT 7
	16	#define PTRACE_KILL 8
	17	#define PTRACE_SINGLESTEP 9
	18
416bc512 RM	19	#define PTRACE_ATTACH 16
416bc512 RM	20	#define PTRACE_DETACH 17
1da177e4 LT	21
	22	#define PTRACE_SYSCALL 24
	23
	24	/* 0x4200-0x4300 are reserved for architecture-independent additions. */
	25	#define PTRACE_SETOPTIONS 0x4200
	26	#define PTRACE_GETEVENTMSG 0x4201
	27	#define PTRACE_GETSIGINFO 0x4202
	28	#define PTRACE_SETSIGINFO 0x4203
	29
2225a122 SS	30	/*
	31	* Generic ptrace interface that exports the architecture specific regsets
	32	* using the corresponding NT_* types (which are also used in the core dump).
c6a0dd7e SS	33	* Please note that the NT_PRSTATUS note type in a core dump contains a full
	34	* 'struct elf_prstatus'. But the user_regset for NT_PRSTATUS contains just the
	35	* elf_gregset_t that is the pr_reg field of 'struct elf_prstatus'. For all the
	36	* other user_regset flavors, the user_regset layout and the ELF core dump note
	37	* payload are exactly the same layout.
2225a122 SS	38	*
	39	* This interface usage is as follows:
	40	* struct iovec iov = { buf, len};
	41	*
	42	* ret = ptrace(PTRACE_GETREGSET/PTRACE_SETREGSET, pid, NT_XXX_TYPE, &iov);
	43	*
	44	* On the successful completion, iov.len will be updated by the kernel,
	45	* specifying how much the kernel has written/read to/from the user's iov.buf.
	46	*/
	47	#define PTRACE_GETREGSET 0x4204
	48	#define PTRACE_SETREGSET 0x4205
	49
3544d72a	50	#define PTRACE_SEIZE 0x4206
fca26f26	51	#define PTRACE_INTERRUPT 0x4207
544b2c91	52	#define PTRACE_LISTEN 0x4208
3544d72a TH	53
	54	/* flags in @data for PTRACE_SEIZE */
	55	#define PTRACE_SEIZE_DEVEL 0x80000000 /* temp flag for development */
	56
1da177e4 LT	57	/* options set using PTRACE_SETOPTIONS */
	58	#define PTRACE_O_TRACESYSGOOD 0x00000001
	59	#define PTRACE_O_TRACEFORK 0x00000002
	60	#define PTRACE_O_TRACEVFORK 0x00000004
	61	#define PTRACE_O_TRACECLONE 0x00000008
	62	#define PTRACE_O_TRACEEXEC 0x00000010
	63	#define PTRACE_O_TRACEVFORKDONE 0x00000020
	64	#define PTRACE_O_TRACEEXIT 0x00000040
	65
	66	#define PTRACE_O_MASK 0x0000007f
	67
	68	/* Wait extended result codes for the above trace options. */
	69	#define PTRACE_EVENT_FORK 1
	70	#define PTRACE_EVENT_VFORK 2
	71	#define PTRACE_EVENT_CLONE 3
	72	#define PTRACE_EVENT_EXEC 4
	73	#define PTRACE_EVENT_VFORK_DONE 5
	74	#define PTRACE_EVENT_EXIT 6
3544d72a	75	#define PTRACE_EVENT_STOP 7
1da177e4 LT	76
	77	#include <asm/ptrace.h>
	78
	79	#ifdef __KERNEL__
	80	/*
	81	* Ptrace flags
260ea101 EB	82	*
	83	* The owner ship rules for task->ptrace which holds the ptrace
	84	* flags is simple. When a task is running it owns it's task->ptrace
	85	* flags. When the a task is stopped the ptracer owns task->ptrace.
1da177e4 LT	86	*/
1da177e4 LT	87
3544d72a	88	#define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */
1da177e4 LT	89	#define PT_PTRACED 0x00000001
	90	#define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */
	91	#define PT_TRACESYSGOOD 0x00000004
	92	#define PT_PTRACE_CAP 0x00000008 /* ptracer can follow suid-exec */
643ad838 TH	93
	94	/* PT_TRACE_* event enable flags */
	95	#define PT_EVENT_FLAG_SHIFT 4
	96	#define PT_EVENT_FLAG(event) (1 << (PT_EVENT_FLAG_SHIFT + (event) - 1))
	97
	98	#define PT_TRACE_FORK PT_EVENT_FLAG(PTRACE_EVENT_FORK)
	99	#define PT_TRACE_VFORK PT_EVENT_FLAG(PTRACE_EVENT_VFORK)
	100	#define PT_TRACE_CLONE PT_EVENT_FLAG(PTRACE_EVENT_CLONE)
	101	#define PT_TRACE_EXEC PT_EVENT_FLAG(PTRACE_EVENT_EXEC)
	102	#define PT_TRACE_VFORK_DONE PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE)
	103	#define PT_TRACE_EXIT PT_EVENT_FLAG(PTRACE_EVENT_EXIT)
1da177e4 LT	104
	105	#define PT_TRACE_MASK 0x000003f4
	106
	107	/* single stepping state bits (used on ARM and PA-RISC) */
	108	#define PT_SINGLESTEP_BIT 31
	109	#define PT_SINGLESTEP (1<<PT_SINGLESTEP_BIT)
	110	#define PT_BLOCKSTEP_BIT 30
	111	#define PT_BLOCKSTEP (1<<PT_BLOCKSTEP_BIT)
	112
	113	#include <linux/compiler.h> /* For unlikely. */
	114	#include <linux/sched.h> /* For struct task_struct. */
	115
481bed45	116
9b05a69e NK	117	extern long arch_ptrace(struct task_struct *child, long request,
9b05a69e NK	118	unsigned long addr, unsigned long data);
1da177e4 LT	119	extern int ptrace_readdata(struct task_struct tsk, unsigned long src, char __user dst, int len);
1da177e4 LT	120	extern int ptrace_writedata(struct task_struct tsk, char __user src, unsigned long dst, int len);
1da177e4	121	extern void ptrace_disable(struct task_struct *);
755e276b	122	extern int ptrace_check_attach(struct task_struct *task, bool ignore_state);
4abf9869 NK	123	extern int ptrace_request(struct task_struct *child, long request,
4abf9869 NK	124	unsigned long addr, unsigned long data);
1da177e4 LT	125	extern void ptrace_notify(int exit_code);
	126	extern void __ptrace_link(struct task_struct *child,
	127	struct task_struct *new_parent);
	128	extern void __ptrace_unlink(struct task_struct *child);
39c626ae	129	extern void exit_ptrace(struct task_struct *tracer);
006ebb40 SS	130	#define PTRACE_MODE_READ 1
	131	#define PTRACE_MODE_ATTACH 2
	132	/* Returns 0 on success, -errno on denial. */
	133	extern int __ptrace_may_access(struct task_struct *task, unsigned int mode);
	134	/* Returns true on success, false on denial. */
	135	extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
1da177e4	136
53b6f9fb ON	137	static inline int ptrace_reparented(struct task_struct *child)
53b6f9fb ON	138	{
0347e177	139	return !same_thread_group(child->real_parent, child->parent);
53b6f9fb	140	}
c6a47cc2	141
1da177e4 LT	142	static inline void ptrace_unlink(struct task_struct *child)
	143	{
	144	if (unlikely(child->ptrace))
	145	__ptrace_unlink(child);
	146	}
	147
4abf9869 NK	148	int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
	149	unsigned long data);
	150	int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
	151	unsigned long data);
1da177e4	152
06d98473 TH	153	/**
	154	* ptrace_parent - return the task that is tracing the given task
	155	* @task: task to consider
	156	*
	157	* Returns %NULL if no one is tracing @task, or the &struct task_struct
	158	* pointer to its tracer.
	159	*
	160	* Must called under rcu_read_lock(). The pointer returned might be kept
	161	* live only by RCU. During exec, this may be called with task_lock() held
	162	* on @task, still held from when check_unsafe_exec() was called.
	163	*/
	164	static inline struct task_struct ptrace_parent(struct task_struct task)
	165	{
	166	if (unlikely(task->ptrace))
	167	return rcu_dereference(task->parent);
	168	return NULL;
	169	}
	170
643ad838 TH	171	/**
	172	* ptrace_event_enabled - test whether a ptrace event is enabled
	173	* @task: ptracee of interest
	174	* @event: %PTRACE_EVENT_* to test
	175	*
	176	* Test whether @event is enabled for ptracee @task.
	177	*
	178	* Returns %true if @event is enabled, %false otherwise.
	179	*/
	180	static inline bool ptrace_event_enabled(struct task_struct *task, int event)
	181	{
	182	return task->ptrace & PT_EVENT_FLAG(event);
	183	}
	184
88ac2921 RM	185	/**
88ac2921 RM	186	* ptrace_event - possibly stop for a ptrace event notification
643ad838	187	* @event: %PTRACE_EVENT_* value to report
88ac2921 RM	188	* @message: value for %PTRACE_GETEVENTMSG to return
88ac2921 RM	189	*
643ad838 TH	190	* Check whether @event is enabled and, if so, report @event and @message
643ad838 TH	191	* to the ptrace parent.
88ac2921	192	*
88ac2921 RM	193	* Called without locks.
88ac2921 RM	194	*/
f3c04b93	195	static inline void ptrace_event(int event, unsigned long message)
88ac2921	196	{
f3c04b93 TH	197	if (unlikely(ptrace_event_enabled(current, event))) {
	198	current->ptrace_message = message;
	199	ptrace_notify((event << 8) \| SIGTRAP);
	200	} else if (event == PTRACE_EVENT_EXEC && unlikely(current->ptrace)) {
	201	/* legacy EXEC report via SIGTRAP */
	202	send_sig(SIGTRAP, current, 0);
	203	}
88ac2921 RM	204	}
88ac2921 RM	205
09a05394 RM	206	/**
	207	* ptrace_init_task - initialize ptrace state for a new child
	208	* @child: new child task
	209	* @ptrace: true if child should be ptrace'd by parent's tracer
	210	*
	211	* This is called immediately after adding @child to its parent's children
	212	* list. @ptrace is false in the normal case, and true to ptrace @child.
	213	*
	214	* Called with current's siglock and write_lock_irq(&tasklist_lock) held.
	215	*/
	216	static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
	217	{
	218	INIT_LIST_HEAD(&child->ptrace_entry);
	219	INIT_LIST_HEAD(&child->ptraced);
6634ae10 ON	220	#ifdef CONFIG_HAVE_HW_BREAKPOINT
	221	atomic_set(&child->ptrace_bp_refcnt, 1);
	222	#endif
	223	child->jobctl = 0;
09a05394	224	child->ptrace = 0;
6634ae10 ON	225	child->parent = child->real_parent;
	226
	227	if (unlikely(ptrace) && current->ptrace) {
09a05394	228	child->ptrace = current->ptrace;
c6a47cc2	229	__ptrace_link(child, current->parent);
09a05394 RM	230	}
	231	}
	232
dae33574 RM	233	/**
	234	* ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
	235	* @task: task in %EXIT_DEAD state
	236	*
	237	* Called with write_lock(&tasklist_lock) held.
	238	*/
	239	static inline void ptrace_release_task(struct task_struct *task)
	240	{
	241	BUG_ON(!list_empty(&task->ptraced));
	242	ptrace_unlink(task);
	243	BUG_ON(!list_empty(&task->ptrace_entry));
	244	}
	245
1da177e4 LT	246	#ifndef force_successful_syscall_return
	247	/*
	248	* System call handlers that, upon successful completion, need to return a
	249	* negative value should call force_successful_syscall_return() right before
	250	* returning. On architectures where the syscall convention provides for a
	251	* separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
	252	* others), this macro can be used to ensure that the error flag will not get
	253	* set. On architectures which do not support a separate error flag, the macro
	254	* is a no-op and the spurious error condition needs to be filtered out by some
	255	* other means (e.g., in user-level, by passing an extra argument to the
	256	* syscall handler, or something along those lines).
	257	*/
	258	#define force_successful_syscall_return() do { } while (0)
	259	#endif
	260
fb7fa8f1 RM	261	/*
	262	* <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
	263	*
	264	* These do-nothing inlines are used when the arch does not
	265	* implement single-step. The kerneldoc comments are here
	266	* to document the interface for all arch definitions.
	267	*/
	268
	269	#ifndef arch_has_single_step
	270	/**
	271	* arch_has_single_step - does this CPU support user-mode single-step?
	272	*
	273	* If this is defined, then there must be function declarations or
	274	* inlines for user_enable_single_step() and user_disable_single_step().
	275	* arch_has_single_step() should evaluate to nonzero iff the machine
	276	* supports instruction single-step for user mode.
	277	* It can be a constant or it can test a CPU feature bit.
	278	*/
	279	#define arch_has_single_step() (0)
	280
	281	/**
	282	* user_enable_single_step - single-step in user-mode task
	283	* @task: either current or a task stopped in %TASK_TRACED
	284	*
	285	* This can only be called when arch_has_single_step() has returned nonzero.
	286	* Set @task so that when it returns to user mode, it will trap after the
dc802c2d RM	287	* next single instruction executes. If arch_has_block_step() is defined,
dc802c2d RM	288	* this must clear the effects of user_enable_block_step() too.
fb7fa8f1 RM	289	*/
	290	static inline void user_enable_single_step(struct task_struct *task)
	291	{
	292	BUG(); /* This can never be called. */
	293	}
	294
	295	/**
	296	* user_disable_single_step - cancel user-mode single-step
	297	* @task: either current or a task stopped in %TASK_TRACED
	298	*
dc802c2d RM	299	* Clear @task of the effects of user_enable_single_step() and
	300	* user_enable_block_step(). This can be called whether or not either
	301	* of those was ever called on @task, and even if arch_has_single_step()
	302	* returned zero.
fb7fa8f1 RM	303	*/
	304	static inline void user_disable_single_step(struct task_struct *task)
	305	{
	306	}
dacbe41f CH	307	#else
	308	extern void user_enable_single_step(struct task_struct *);
	309	extern void user_disable_single_step(struct task_struct *);
fb7fa8f1 RM	310	#endif /* arch_has_single_step */
fb7fa8f1 RM	311
dc802c2d RM	312	#ifndef arch_has_block_step
	313	/**
	314	* arch_has_block_step - does this CPU support user-mode block-step?
	315	*
	316	* If this is defined, then there must be a function declaration or inline
	317	* for user_enable_block_step(), and arch_has_single_step() must be defined
	318	* too. arch_has_block_step() should evaluate to nonzero iff the machine
	319	* supports step-until-branch for user mode. It can be a constant or it
	320	* can test a CPU feature bit.
	321	*/
5b88abbf	322	#define arch_has_block_step() (0)
dc802c2d RM	323
	324	/**
	325	* user_enable_block_step - step until branch in user-mode task
	326	* @task: either current or a task stopped in %TASK_TRACED
	327	*
	328	* This can only be called when arch_has_block_step() has returned nonzero,
	329	* and will never be called when single-instruction stepping is being used.
	330	* Set @task so that when it returns to user mode, it will trap after the
	331	* next branch or trap taken.
	332	*/
	333	static inline void user_enable_block_step(struct task_struct *task)
	334	{
	335	BUG(); /* This can never be called. */
	336	}
dacbe41f CH	337	#else
dacbe41f CH	338	extern void user_enable_block_step(struct task_struct *);
dc802c2d RM	339	#endif /* arch_has_block_step */
dc802c2d RM	340
85ec7fd9 ON	341	#ifdef ARCH_HAS_USER_SINGLE_STEP_INFO
	342	extern void user_single_step_siginfo(struct task_struct *tsk,
	343	struct pt_regs regs, siginfo_t info);
	344	#else
	345	static inline void user_single_step_siginfo(struct task_struct *tsk,
	346	struct pt_regs regs, siginfo_t info)
	347	{
	348	memset(info, 0, sizeof(*info));
	349	info->si_signo = SIGTRAP;
	350	}
	351	#endif
	352
1a669c2f RM	353	#ifndef arch_ptrace_stop_needed
	354	/**
	355	* arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
	356	* @code: current->exit_code value ptrace will stop with
	357	* @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
	358	*
	359	* This is called with the siglock held, to decide whether or not it's
	360	* necessary to release the siglock and call arch_ptrace_stop() with the
	361	* same @code and @info arguments. It can be defined to a constant if
	362	* arch_ptrace_stop() is never required, or always is. On machines where
	363	* this makes sense, it should be defined to a quick test to optimize out
	364	* calling arch_ptrace_stop() when it would be superfluous. For example,
	365	* if the thread has not been back to user mode since the last stop, the
	366	* thread state might indicate that nothing needs to be done.
	367	*/
	368	#define arch_ptrace_stop_needed(code, info) (0)
	369	#endif
	370
	371	#ifndef arch_ptrace_stop
	372	/**
	373	* arch_ptrace_stop - Do machine-specific work before stopping for ptrace
	374	* @code: current->exit_code value ptrace will stop with
	375	* @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
	376	*
	377	* This is called with no locks held when arch_ptrace_stop_needed() has
	378	* just returned nonzero. It is allowed to block, e.g. for user memory
	379	* access. The arch can have machine-specific work to be done before
	380	* ptrace stops. On ia64, register backing store gets written back to user
	381	* memory here. Since this can be costly (requires dropping the siglock),
	382	* we only do it when the arch requires it for this particular stop, as
	383	* indicated by arch_ptrace_stop_needed().
	384	*/
	385	#define arch_ptrace_stop(code, info) do { } while (0)
	386	#endif
	387
bbc69863 RM	388	extern int task_current_syscall(struct task_struct target, long callno,
	389	unsigned long args[6], unsigned int maxargs,
	390	unsigned long sp, unsigned long pc);
	391
bf26c018 FW	392	#ifdef CONFIG_HAVE_HW_BREAKPOINT
	393	extern int ptrace_get_breakpoints(struct task_struct *tsk);
	394	extern void ptrace_put_breakpoints(struct task_struct *tsk);
	395	#else
	396	static inline void ptrace_put_breakpoints(struct task_struct *tsk) { }
	397	#endif /* CONFIG_HAVE_HW_BREAKPOINT */
	398
	399	#endif /* __KERNEL */
1da177e4 LT	400
1da177e4 LT	401	#endif