Merge branch 'akpm'

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.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.  */
#include <linux/err.h>                  /* for IS_ERR_VALUE */


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        0x01
#define PTRACE_MODE_ATTACH      0x02
#define PTRACE_MODE_NOAUDIT     0x04
/* 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);

                if (child->ptrace & PT_SEIZED)
                        task_set_jobctl_pending(child, JOBCTL_TRAP_STOP);
                else
                        sigaddset(&child->pending.signal, SIGSTOP);

                set_tsk_thread_flag(child, TIF_SIGPENDING);
        }
}

/**
 * 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

#ifndef is_syscall_success
/*
 * On most systems we can tell if a syscall is a success based on if the retval
 * is an error value.  On some systems like ia64 and powerpc they have different
 * indicators of success/failure and must define their own.
 */
#define is_syscall_success(regs) (!IS_ERR_VALUE((unsigned long)(regs_return_value(regs))))
#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